Technical Design Savina Stena_final
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Technical Design Savina Stena_final...
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Ad-Hoc Report No. 1: Solid Waste Management in North Kosovo
Support Waste Management in Kosovo EuropeAid/133800/C/SER/XK
Design of “Savina Stena” Sanitary Landfill “Solid Waste Management in North Kosovo” Contract Number: CRIS 2013/335 128
JUNE 2014 AN EU FUNDED PROJECT Managed by the European Union Office in Kosovo
A project implemented by:
Europe Aid / 133800 / C / S E R / XK Thisproject is financedbytheEuropeanUnion. This document hasbeen p roduced with thefinancial assistance of the EuropeanUnion
DESIGN OF SAVINA STENA SANITARY LANDFILL
Table of Content 1
PROJECT BACKGROUND ............................................................................................................ 1
2
GENERAL INFORMATION .......................................................................................................... 2
3
4
2.1
LOCATION - TOPOGRAPHY ....................................................................... 2
2.2
GEOLOGY - HYDROGEOLOGY ..................................................................... 3
2.3
CLIMATIC DATA .................................................................................... 4
2.3.1
CLIMATIC CONDITIONS IN NORTHERN KOSOVO ........................................... 4
2.3.2
Air temperature ................................................................................. 5
2.3.3
Precipitation& Humidity ....................................................................... 8
2.3.4
Solar radiation................................................................................. 10
2.3.5
Wind ............................................................................................ 11
GENERAL REQUIREMENTS ...................................................................................................... 13 3.1
SCOPE OF THE WORKS .......................................................................... 13
3.2
INTERFACES AND LIMITS OF SUPPLY......................................................... 14
3.2.1
Access Road.................................................................................... 14
3.2.2
Power supply .................................................................................. 14
3.2.3
Potable Water ................................................................................. 14
3.2.4
Phone Line ..................................................................................... 14
LANDFILL ................................................................................................................................... 15 4.1
GENERAL DESIGN PLAN ........................................................................ 15 Design parameters and assumptions ....................................................... 15
4.1.1 4.1.1.1
Basin configuration ........................................................................ 15
4.1.1.2
Quantity and composition of waste to be deposited ..................................... 16 Design philosophy ............................................................................ 17
4.1.2 4.1.2.1
Basin configuration ........................................................................ 17
4.1.2.2
Lining System ............................................................................... 18
4.1.2.3
Leachate Collection System ................................................................ 20
4.1.2.4
Leachate treatment ........................................................................ 21
4.1.2.5
Biogas management........................................................................ 22
4.1.2.6
Environmental monitoring ................................................................ 23
4.1.2.7
Utilities and structures ..................................................................... 23
4.2 4.2.1
EARTH WORKS ................................................................................... 25 Excavations and filling works................................................................ 25
DESIGN OF SAVINA STENA SANITARY LANDFILL
Cell A construction ............................................................................ 26
4.2.2 4.3
CALCULATION OF CELL LIFETIME ............................................................ 26
4.4
BOTTOM LINING CONSTRUCTION ............................................................. 27
4.4.1
Introduction ................................................................................... 27
4.4.2
Compacted Clay liner ......................................................................... 27
4.4.3
Geosynthetic liner – polymer membrane .................................................. 30
4.4.4
Geotextile ...................................................................................... 33
4.4.5
Sand layer ...................................................................................... 34
4.4.6
Drainage layer ................................................................................. 34
4.5
LEACHATE MANAGEMENT ..................................................................... 36
4.5.1
Leachate generation - composition ......................................................... 36
4.5.2
Leachate production .......................................................................... 37
4.5.3
Leachate collection ........................................................................... 44
4.6
LEACHATE TREATMENT ........................................................................ 48
4.6.1
Introduction ................................................................................... 48
4.6.2
Leachate treatment plant of Savina Stena Landfill ........................................ 50
4.6.3
Recirculation .................................................................................. 62
4.7
BIOGAS MANAGEMENT ......................................................................... 64
4.7.1
Introduction ................................................................................... 64
4.7.2
Estimation of landfillgasproduction ........................................................ 65
4.7.3
Biogas management system – Technical specifications .................................. 68
4.8
FLOOD PROTECTION ............................................................................ 73 Hydrology ...................................................................................... 74
4.8.1 4.9
LANDFILL MONITORING ........................................................................ 84
4.9.1
Introduction ................................................................................... 84
4.9.2
Leachate monitoring system ................................................................. 84
4.9.3
Groundwater monitoring system ........................................................... 87
4.9.4
Surface water monitoring system ........................................................... 89
4.9.5
Biogas monitoring system ................................................................... 89
4.9.6
Settlements monitoring system ............................................................. 91
4.9.7
Monitoring of water conditions – Recording of data ...................................... 91
4.9.8
Volume and composition of incoming waste and soil material .......................... 92
4.10
GENERAL INFRASTRUCTURES - UTILITIES................................................... 93
4.10.1
Introduction ................................................................................ 93
4.10.2
Main entrance - fencing ................................................................... 93
DESIGN OF SAVINA STENA SANITARY LANDFILL
4.10.3
Weighbridge building ..................................................................... 94
4.10.4
Weighbridge ................................................................................ 94
4.10.5
Sampling area .............................................................................. 94
4.10.6
Administration building ................................................................... 94
4.10.7
Maintenance building...................................................................... 95
4.10.8
Water tank .................................................................................. 95
4.10.9
Parking for personnel and visitors ....................................................... 96
4.10.10
Tire washing system ....................................................................... 96
4.10.11
Fire Protection zone: ...................................................................... 96
4.10.12
Green areas ................................................................................. 97
4.10.13
Fire fighting system ........................................................................ 97
4.10.14
General formulation of the area .......................................................... 97
4.11
5
6
ROAD WORKS .................................................................................... 98
4.11.1
Introduction ................................................................................ 98
4.11.2
Temporary roads .......................................................................... 98
4.11.3
Internal road................................................................................ 99
4.11.3.1
Horizontal and Vertical Alignment – Typical Cross-Section ............................ 99
4.11.3.2
Road layers .................................................................................. 99
4.11.3.3
Internal Road Layers ..................................................................... 100
4.11.3.4
Embankments construction ............................................................. 100
4.11.4
Access Road............................................................................... 100
LANDFILL CLOSURE AND AFTERCARE................................................................................ 104 5.1
INTRODUCTION ................................................................................ 104
5.2
LANDFILL CLOSURE ........................................................................... 104
5.2.1
Landfill capping ............................................................................. 104
5.2.2
Cap stability.................................................................................. 109
5.2.3
Settlement ................................................................................... 109
5.2.4
Land Use Options ........................................................................... 110
LANDFILL OPERATION .......................................................................................................... 112 6.1
ESTIMATION OF THE QUANTITY OF PRODUCED WASTE ................................ 112
6.2
FILL SEQUENCE PLAN ......................................................................... 112
6.3
DESCRIPTION OF THE SANITARY LANDFILLING PROCESS .............................. 113
6.3.1
Cell geometrical Characteristics ........................................................... 113
6.3.2
Direction and schedule of fulfilling the landfill .......................................... 113
DESIGN OF SAVINA STENA SANITARY LANDFILL
6.3.3
Daily Cover – Intermediate Cover ......................................................... 114
6.3.4
Compaction of the Waste ................................................................... 115
6.3.5
Truck movement and unloading .......................................................... 116
6.3.6
Disposal of difficult waste .................................................................. 117
6.3.7
Keep area Well-Drained .................................................................... 118
6.4
CONTROL MEASURES ......................................................................... 118
6.4.1
Incoming Waste Control.................................................................... 118
6.4.2
Odours Control .............................................................................. 118
6.4.3
Odours from Incoming Waste ............................................................. 119
6.4.4
Odours from In-Place Waste ............................................................... 119
6.4.5
Odours from a Leachate evaporation pond .............................................. 119
6.4.6
Odours from Landfill Gas ................................................................... 119
6.4.7
Dust Control ................................................................................. 119
6.4.8
Vector Control ............................................................................... 120
6.4.9
Litter Control ................................................................................ 120
6.4.10 6.5
7
8
Working Hours ........................................................................... 120
EMPLOYEE ASSIGNMENTS AND RESPONSIBILITIES ...................................... 121
6.5.1
Senior Engineer ............................................................................. 121
6.5.2
Disposal Site Supervisor ................................................................... 122
6.5.3
Utility worker................................................................................ 123
6.5.4
Landfill Equipment Operator .............................................................. 123
6.5.5
Equipment Mechanic ....................................................................... 124
6.5.6
Labourer ..................................................................................... 124
6.5.7
Senior Management Analyst/Fee Booth Supervisor .................................... 125
6.5.8
Fee Booth Operator ......................................................................... 126
6.5.9
Security Personnel .......................................................................... 127
MOBILE EQUIPMENT.............................................................................................................. 128 7.1
MAIN TECHNICAL SPECIFICATIONS OF MOBILE EQUIPMENT ........................ 128
7.1.1
Front end loader ............................................................................ 128
7.1.2
Landfill compactor .......................................................................... 130
AFTERCARE PROCEDURES .................................................................................................... 132 8.1
POST CLOSURE-MAINTENANCE PLAN ................................................... 132
DESIGN OF SAVINA STENA SANITARY LANDFILL
1
PROJECT BACKGROUND
The project refers to the development of one sanitary landfill in North Kosovo.The new landfill will serve the Municipalities of Leposaviq / Leposavić, Mitrovicë / Mitrovica (north), Zveçan / Zvečane, and Zubin Potok. The construction of the landfill, will be based on the detailed design that will be submitted by the Contractor and will be evaluated. It is noted that the technical solution described in these terms of reference is indicative. The tenderers should provide their own calculations and design. However the tenderers should be in line with the specifications presented. This project falls under the European Union’s (EU) “Instrument for Pre-Accession Assistance” (IPA) programme, replaces a series of European Union programmes and financial instruments for candidate countries or potential candidate countries. The overall project concept is, for the North Kosovo region, to reduce gaps in quality and service level between the present waste management system and the requirements of EU legislation and standards. The proposed project is meeting the general strategy of environmental protection adopted by National Strategy Plan referring to environmental protection, providing the improvement of waste management. The Plan stipulates the priority of measures aiming the reducing of severe local pollution or of those ones which may affect the human health, e.g. the existent landfill leachate percolating into the groundwater, uncontrolled waste landfilling or uncontrolled emissions of air pollutants resulted from waste decay. This study has been elaborated from the Consortium EPEM – SLR – ISPE.
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DESIGN OF SAVINA STENA SANITARY LANDFILL
2 2.1
GENERAL INFORMATION LOCATION - TOPOGRAPHY
The new landfill will serve the Municipalities of Leposaviq / Leposavić, Mitrovicë / Mitrovica (north), Zveçan / Zvečane, and Zubin Potok. The served population is estimated to app. 60.000 inhabitants in the year of 2015. The New Sanitary Landfill (SL), will be located in ZvecanMunicipalitythe latitude and longitude of the site is 42o 58’12.99’’, 20o 49’35’’.
Figure 2-1: Location of Savina Stena Sanitary Landfill
The site of the SL is public property, except the access road, app. 2,5km, which is private property and expropriation will take place. The distances from the settlements are:
Mitrovica 8,2km
Viahinje 3,6 km
Zobin Potok 12,1 km
Banjska 3,1 km
Zvecan 6,2 km
Saljska Bistrica 5,1km
Srbovac 1,6 km
Josevic 1,3 km
Valac 2,1 km
Lokva 4,8 km
Zhazhe 3,3 km
It has a total area of 26,6 ha while the area allocated for the landfill (cellΑ) is app. 3 ha (2,92ha). 2| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
The proposed site is on the highway Raska- Mitrovica with the toponym “Savina Stena”. More specifically, it concerns an area that extends in a natural thalweg above the river Iber / Ibar. The site is a public property. The area is characterized by relatively strong relief. In fact, it is a basin bounded by the hills slopes of which have gradients of approximately 35-40 %. Downstream of the proposed site there is Iber / Ibar river, therefore extensive flood works should take place in order to protect it.
2.2
GEOLOGY - HYDROGEOLOGY
The area where landfill is planned to be built is mainly composed from ultramafic rocks. These formations stretch in the northern and south-eastern part, and they meet with the boundary of serpentinite massif of the river Iber. Most of these rocks belong to serpentinisedharzburgite. With intense serpentinisation of ultramafics they are transformed into serpentinite. These are serpentinisedharzburgite in which the primary minerals we find remains of olivine, piroksen rhombic and chrome-spinel as an accessory. In the hydrogeological aspect study area consists from fissured aquifers with medium to low fracture permeability (10-5 m/s to 10-9 m/s) are mainly Neogene, Palaeogene, Jurassic and Palaeozoic consolidated sedimentary, igneous and metamorphic rocks. Beside these, Oligocene fractured pyroclastites in the north-eastern part of Mitrovica can be considered as local productive aquifers. In the northern part Mitrovica, fractured Jurassic (serpentinised) peridotites and sericiteschists are characterised by local ground water flow through fractures. The volcanic-sedimentary series has a large spreading and lies in the south-western part of the studied area. This melange belongs to the lower senonian, the genesis of which is connected with the movements of the crease phase. This mélange is developed in the Mitrovica-Banjska direction, and has the general stretch NW-SE, while the width varies. Composition of lower session of the melange, and areas where it is formed, indicates the existence of a graben which was partially below sea surface. This mélange consists of: limestone, marlstone, mudstone, Sandstone, conglomerate etc. In the valley of Iber river are clearly expressed two levels of river terrace: the old (t2) and new (t1), immediately above the river flow. The older terraces have a greater variety of lithological structure. Alluvial deposits build large areas around the Iber River. They appear with gravel and sand, with rare layers of clay. In the area being studied, due to the configuration of the terrain, alluvial deposits have limited stretch. As far as the hydrogeology is concerned, the basic element responsible for the water-bearing capacity of the rocks is their hydraulic type: this may result in intergranular aquifers, fissured aquifers, Fissured and karstified aquifers, mixed porosity and porous and fissured rocks with low productivity or rocks practically without groundwater. Area where is planned to build the landfill is mostly construction from fissured aquifers. Those aquifers are with medium to low fracture permeability (10-5 m/s to 10-9 m/s) is mainly Neogene, Palaeogene, Jurassic and Palaeozoic consolidated sedimentary, igneous and metamorphic rocks. Among the Miocene sedimentary rocks, fissured conglomerates, sandstones, mudstones, marlstones and marlyclaystones in the eastern part of Kosovo are considered as aquifers. 3| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Regarding the soil the area of study is built from the soil of typical rendzina on serpentinite. The characteristic of these soils is that they are thick layers and they are without forestry. The area where the landfill is planned to be built, belongs to the Internal Vardar subzone. In this area are separate the Ibar syncline, Sitinica and Kacandoli faults. Possibility of earthquake strikes in Mitrovica, more precisely in this study area, which theoretically as per available data (from Seismological Report of Kosova), can be with intensity of seven (MSK64).
2.3
CLIMATIC DATA
Kosovo’s climate is influenced by its proximity to the Adriatic and Aegean Seas as well as the continental European landmass to the north. The overall climate is a modified continental type, with some elements of a sub-Mediterranean climate in the extreme south and an alpine regime in the higher mountains. Winters are cold with an average temperature in January and February of 0 degrees centigrade and with significant accumulation of snow, especially in the mountains. Summers are hot, with extremes of up to 40 degrees. The average annual rainfall in Kosovo is 720 mm but can reach more than 1,000 mm in the mountains. Summer droughts are not uncommon. The varied elevations, climatic influences, and soils within Kosovo provide a wide diversity of microhabitats to which plant and animal species are adapted.
2.3.1 CLIMATIC CONDITIONS IN NORTHERN KOSOVO The morphological, i.e. hypsometric characteristics of the terrain have impacted Northern Kosovo climate characteristics. The Climate is temperate-continental to mountain climate. The mountain ranges of Mokra Gora, Rogozna, Suva Planina and southern and south-western slopes of Kopaonik have their specific impacts in climate characteristics. For the parameters analysis the data of precipitations, temperatures, sunshine, wind and humidity are obtained from the climatology stations Kopaonik, Novi Pazar, Mitrovica and Pec, surrounding the terrain. These parameters are used for the analyzed period from 1961-1999. From 1999 until 2014 the data were obtained from the meteorological stations presented in the table below. Table 2-1: Meteorological Stations surrounding research terrain Longitude [°]
Latitude [°]
Altitude [m]
Distance [km]
Direction [Ο/degree s]
Directi on
Station Name
Country Name
20.7
43.7
217
91,1
351
N
KRALJEVO
SERBIA
2
21.9
43.33
202
96,9
59
NE
NIS
SERBIA
3
21.65
41.96
239
121,6
148
SE
SKOPJE-PETROVAC
FYRΟΜ
4
22.28
42.51
1176
122,7
110
E
5
19.28
42.43
52
139,7
249
W
6
19.25
42.36
33
145,1
247
SW
7
20.7
41.53
1321
151,9
185
S
SKOPJE PODGORICA (TITOGRAD) PODGORICAGOLUBOVCI LAZAROPOLE
FYRΟΜ MONTENEG RO MONTENEG RO FYRΟΜ
8
22.18
41.75
327
166,3
139
SE
STIP
FYRΟΜ
9
23.38
42.65
595
206,6
97
E
SOFIA-(OBSERV.)
BULGARIA
1
21.36
41.05
589
208,6
169
S
BITOLA
FYRΟΜ
1
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DESIGN OF SAVINA STENA SANITARY LANDFILL
Longitude [°]
Latitude [°]
Altitude [m]
Distance [km]
Direction [Ο/degree s]
Directi on
Station Name
Country Name
0
Also, for the precipitation analysis there are used the data from Climatic Atlas, for the period 1930 – 1960. In that time the precipitations stations were numerous in this region (Ribarići, Brnjak, Režala, Kosovska Mitrovica, Banjska, Vlahinje, Leposavic and Lesak).
2.3.2 Air temperature The influence of the mountain range is obvious in the analysis of the temperature regime. The air temperature in the highest parts are reaching –30oC, during the winters. So, the average temperature in the research area varies from 3,7 (CS Kopaonik) to 11,4oC (CS Peć). The coldest month is January, with mean temperature from –4oC CKS Kopaonik) to1oC (CS Peć). August is the hottest with mean temperature varying from 13oC (CS Kopaonik) to 22,1oC (CS Peć). The altitude, micro-climate and spatial distribution of the relevant climate stations reflects the conditions on the site, so the data are valid for this research terrain. In the Tables 2-2, 2-3 and 2-4, the average air temperature is presented at the Climatology stations of Novi Pazar, Kopaonik and Pec, respectively. Table 2-2: Average monthly air temperatures at the CS Novi Pazar for the period of 1991-2001 Year
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
-1,9
-1,2
7,7
8,1
10,9
18
19,2
17,9
16,1
9,6
6,0
-3,1
8,9
1992
-1,6
0,6
4,4
9,6
13,8
17,1
18,8
21,4
16,1
11,9
5,8
-0,6
9,7
1993
-2,3
-2,2
2,9
9,9
14,7
17,8
19,4
20,1
15,0
12,4
3,4
2,3
9,5
1994
1,1
1,3
7,7
10,3
15,1
17,7
19,7
20,4
18,9
10,0
5,9
0,8
10,7
1995
-2,2
4,3
4,8
8,8
13,5
17,8
20,6
17,9
13,9
9,7
2,2
2,8
9,5
1996
0,3
-0,9
1,9
9,3
15,7
18,7
19,1
19,5
12,9
10,4
6,2
-0,8
9,4
1997
0,9
2,6
4,5
5,4
15,3
20,0
19,7
18,1
14,7
7,6
6,4
1,7
9,7
1998
1,4
2,6
3,0
11,9
14,1
19,5
21,2
20,9
15,4
11,3
3,5
-3,2
10,2
1999
0,1
0,3
5,8
8,7
14,0
18,2
19,9
20,6
17,0
10,8
5,2
0,5
10,1
2000
-3,0
1,5
5,5
13,1
17,2
19,3
21,4
21,4
15,1
12,0
8,3
1,7
11,2
2001
2,8
2,9
10,3
9,3
16,1
17,7
20,9
21,9
14,9
12,6
3,9
-3,9
10,8
min.
-3,0
-2,2
1,9
5,4
10,9
17,1
18,8
17,9
12,9
7,6
2,2
-3,9
8,9
max
2,8
4,3
10,3
13,1
17,2
20,0
21,4
21,9
18,9
12,6
8,3
2,8
11,2
mean
-0,4
1,1
5,3
9,5
14,6
18,3
20,0
20,0
15,5
10,8
5,2
-0,2
10,0
Table 2-3: Average monthly air temperatures at the CS Novi Pazar for the period of 1991-2002 Year
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
-5,0
-6,3
1,3
-0,4
2,4
11,0
12,2
10,5
9,7
3,2
0,2
-7,9
2,6
1992
-3,9
-6,1
-3,1
1,0
6,3
9,6
11,5
16,1
9,0
5,7
0,7
-4,5
3,6
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DESIGN OF SAVINA STENA SANITARY LANDFILL
Year
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1993
-3,8
-7,1
-4,1
2,0
7,8
10,6
12,5
13,9
9,1
8,2
-0,2
-1,4
4,0
1994
-2,6
-4,1
0,6
2,3
7,8
10,6
12,8
14,2
12,4
4,6
0,4
-2,8
4,7
1995
-6,3
-1,6
-3,3
1,0
6,0
10,3
13,6
10,7
7,0
5,2
-3,7
-1,6
3,1
1996
-4,4
-5,8
-6,3
1,2
8,3
11,4
12
12,3
4,8
3,1
2,0
-2,2
3,0
1997
-1,4
-4,1
-3,7
-3,7
7,2
12,0
11,4
10,3
7,9
1,7
1,2
-3,5
2,9
1998
-3,2
-1,8
-5,8
3,3
6,0
11,9
13,7
13,9
8,3
5,3
-2,4
-5,6
3,7
1999
-2,8
-6,9
-1,8
2,4
8,3
11,3
12,6
13,8
10,3
5,5
0,1
-3,3
4,2
2000
-8,3
-5,1
-3,0
4,6
9,0
11,4
13,3
14,6
8,3
6,3
3,7
-1,3
4,5
2001
-2,3
-4,3
2,5
1,4
8,1
9,3
13,2
14,2
7,8
7,3
-2,1
-8,9
3,9
2002
-4,0
-0,6
0,1
2,1
8,5
11,5
13,9
11,6
6,9
9,8
2,7
-3,0
4,6
min.
-8,3
-7,1
-6,3
-3,7
2,4
9,3
11,4
10,3
4,8
1,7
-3,7
-8,9
2,6
max
-1,4
-0,6
2,5
4,6
9,0
12,0
13,9
16,1
12,4
9,8
3,7
-1,3
4,7
mean
-4,0
-4,5
-2,2
1,4
7,1
10,9
12,7
13,0
8,5
5,5
0,2
-3,8
3,7
Table 2-4: Average monthly air temperatures at the CS Pec for the period of 1991-1998 Year
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
-1,0
2,0
9,0
9,0
11,9
20,1
20,6
20,3
18,0
11,3
6,8
2,0
10,8
1992
-0,1
2,2
6,6
11,4
15,0
16,7
21,2
24,9
15,4
13,0
7,1
0,6
11,7
1993
0,1
-0,5
4,9
11,7
17,1
20,1
22,0
23,3
17,4
13,6
4,2
4,1
11,5
1994
3,0
2,5
9,5
10,9
17,2
20,1
21,9
23,3
20,7
11,6
7,4
1,8
12,5
1995
-0,2
5,8
5,5
10,5
15,2
19,6
22,7
19,5
15,2
12,1
3,5
3,8
11,1
1996
1,2
0,3
2,5
10,8
17,1
21,5
21,9
21,9
14,0
11,2
7,6
2,0
11,0
1997
1,5
3,8
6,3
6,6
16,7
21,1
21,6
20,1
17,3
9,1
6,5
2,5
11,1
1998
3,4
4,7
4,4
12,6
15,0
21,2
23,2
23,3
16,5
12,4
4,0
-2,0
11,6
min.
-1,0
-0,5
2,5
6,6
11,9
16,7
20,6
19,5
14,0
9,1
3,5
-2,0
10,8
max
3,4
5,8
9,5
12,6
17,2
21,5
23,2
24,9
20,7
13,6
7,6
4,1
12,5
mean
1,0
2,6
6,1
10,4
15,7
20,1
21,9
22,1
16,8
11,8
5,9
1,9
11,4
Table 2-5: Temperature data from the surrounding meteorological stations as listed in the Table 2-1 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Year
Mean Temperature 1
0,4
3,0
6,5
11,1
15,6
19,3
21,2
21,1
17,6
12,3
7,6
2,7
11,5
2
0,4
3,0
6,0
9,6
14,8
18,5
20,2
19,8
16,0
10,8
6,0
1,6
10,5
3
0,5
3,0
6,1
10,8
15,3
19,1
21,2
21,5
17,3
12,0
7,1
2,7
11,4
4
-0,4
2,0
5,5
10,1
14,8
18,7
20,3
20,6
16,7
11,3
6,5
1,7
10,7
5
0,6
3,7
6,5
10,6
15,8
19,1
21,0
20,6
17,0
11,8
7,0
11,8
12,1
6
-0,5
1,2
5,0
11,3
15,8
19,2
21,5
21,2
17,8
12,1
7,0
3,0
11,2
7
-0,7
2,2
5,6
10,1
15,0
18,3
20,2
20,0
16,6
11,5
7,1
1,6
10,6
6| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Year
8
0,4
3,0
7,5
11,6
16,2
19,3
21,2
21,6
18,2
12,8
6,3
2,5
11,7
9
-1,8
0,1
-3,3
5,9
10,0
15,0
19,3
15,8
17,5
9,0
4,5
0,8
7,7
10
1,5
4,3
7,0
11,0
16,2
19,8
21,6
21,2
17,6
12,1
7,8
2,7
11,9
0,04
2,55
5,24
10,21
14,95
18,63
20,77
20,34
17,23
11,57
6,69
3,11
10,93
Maximum Temperature 1
3,4
6,0
9,8
17,1
21,7
25,3
28,2
28,5
25,1
18,0
11,1
6,5
16,7
2
4,0
7,1
12,8
17,7
22,7
26,0
28,3
28,7
25,3
19,2
10,8
6,0
17,4
3
4,3
8,3
13,8
18,5
23,7
27,5
30,0
30,0
26,0
19,2
10,1
5,0
18,0
4
4,6
8,3
11,8
19,2
23,2
28,0
30,7
31,1
26,0
18,5
11,6
7,4
18,4
5
9,1
10,6
14,3
19,2
24,2
29,0
32,5
32,5
27,5
21,0
15,0
11,8
20,5
6
9,5
11,3
15,1
19,1
24,2
28,2
31,7
31,7
27,2
21,7
15,3
11,1
20,5
7
2,2
3,0
6,0
10,6
15,5
18,8
22,2
22,2
18,7
13,3
8,0
4,0
12,0
8
4,5
8,1
12,6
18,1
23,2
27,2
30,1
30,0
26,2
19,5
11,8
6,0
18,1
9
2,2
5,0
9,8
15,3
20,1
23,5
25,8
25,7
22,6
16,6
9,6
4,0
15,0
10
3,2
6,5
11,3
16,5
21,7
25,8
28,6
28,5
24,7
18,2
11,5
5,3
16,8
4,7
7,42
11,73
17,13
22,02
25,93
28,81
28,89
24,93
18,52
11,48
6,71
17,34
Minimum Temperature 1
-4,2
-3,6
0,2
5,5
10,0
13,1
14,8
14,0
10,6
6,4
2,9
-0,7
5,7
2
-3,0
-1,3
2,4
6,0
10,1
13,3
14,6
14,6
11,5
7,0
2,2
-0,9
6,4
3
-3,5
-1,3
1,8
5,4
9,8
13,1
14,8
14,6
11,3
6,3
1,2
-2,5
5,9
4
-3,0
-2,5
0,6
5,3
10,1
13,3
15,1
14,3
11,1
5,9
2,9
-1,2
6,0
5
2,2
2,5
5,4
9,3
13,6
17,7
20,7
20,6
17,0
11,6
7,5
4,4
11,0
6
1,3
3,0
5,8
9,1
13,5
17,2
20,2
20,2
16,5
11,6
6,8
2,9
10,7
7
-6,0
-5,0
-2,8
1,1
5,0
7,8
9,3
9,3
7,0
3,5
0,0
-4,0
2,1
8
-2,8
-0,9
2,5
6,5
11,0
14,3
16,1
15,8
12,3
7,6
3,0
-1,2
7,0
9
-5,0
-3,0
0,3
4,6
9,3
12,3
13,8
14,3
10,6
5,6
1,2
-2,8
5,1
10
-4,5
-2,3
1,2
5,0
8,6
11,6
13,1
12,8
9,8
5,5
1,7
-2,6
5,0
-2,85
-1,44
1,74
5,78
10,1
13,37
15,25
15,05
11,77
7,1
2,94
-0,86
6,49
7| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Month
Figure 2-2: Graphic presentation of the temperature regime in North Kosovo, minimum (green), Maximum (blue) and Mean (red)
2.3.3 Precipitation& Humidity Based on the available data, it can be seen that there are relatively small oscillations of precipitations during the year, or that the precipitations are evenly distributed throughout the year. That is very good from the hydrology point of view, as that stable regime enables stabile regime of the ground waters. The average precipitations for the region are 600–855 mm on the mountain slopes Kopaonik, Mokragora and Suva planina, in strong winters the number of days with snow is up to 180, effecting significantly the ground waters. The most of the precipitations are recorded in April, May and October. Table 2-6: Monthly precipitations distribution throughout measured at the CS Kopaonik Month
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
24,5
46,5
74
118,5
127,8
62,1
187,8
88
43,8
102,7
85,5
66,0
1027,2
1992
26,5
116,6
62,3
86,6
17,2
318,7
71,7
32,2
10,3
86,2
133,2
60,7
1000,2
1993
33,3
31,7
96,2
65,9
96,3
64,2
45,9
24,9
92,3
30,3
52,5
103,4
736,9
1994
75,2
29,1
55,5
110.7
66,9
107,6
128,6
48,2
77,4
75,5
31,6
51,4
857,7
1995
128,9
58,9
102,4
118,4
169
96,2
76,4
120,1
139,2
2,5
94,9
77,8
1184,7
1996
19,5
52,4
81,9
104,6
122,6
59,2
26,2
99,3
237,9
91,4
118,2
88,9
1102,1
1997
17,2
43,8
82
140,8
108,7
37,7
114
174,5
31.9
97,8
19,4
69,1
936,9
1998
32,3
30,3
76,4
78,8
98,3
86,6
50,2
68,0
148,8
115,8
69,9
57,7
913,1
1999
41,4
95,8
31,10
114
85,7
128,5
187,4
28,6
67,7
52,7
102,6
107,6
1043,1
2000
80,2
80,6
101,0
85,0
70,5
68,3
54.7
10,5
129,5
32,9
38,4
55,1
806,7
2001
31,5
67,4
52,3
152,7
151,9
200,3
84,3
84,4
232,3
17,9
115,7
39,7
1230,4
min.
17,2
29,1
31,1
65,9
17,2
37,7
26,2
10,5
10,3
2,5
19,4
39,7
736,9
max
128,9
116,6
102,4
152,7
169,0
318,7
187,8
174,5
237,9
115,8
133,2
107,6
1230,4
Year
8| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
mean
46,4
59,4
74,1
106,5
101,4
111,8
97,3
70,8
117,9
64,2
78,4
70,7
985,4
Table 2-7: Monthly precipitations distribution throughout measured at the CS Novi Pazar Month
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
12,9
42,4
44,8
81,2
45,3
30,3
97,5
65,0
36,4
71,0
55,3
38,3
620,4
1992
13,0
22,9
24,4
76,5
28,5
73,5
65,5
13,9
25,7
68,3
78,1
20,8
511,1
1993
91,1
14,0
73,7
31,2
35,3
Z7,6
39,7
25,9
65
29,6
56,0
54,1
515,4
1994
35,5
24,6
15,5
31,4
53,9
91,9
169,0
50,5
36,8
33,0
13,7
56,2
612,0
1995
94,5
50,8
56,6
29,0
60,8
30,7
62,1
42,3
91,5
0,0
48,0
58,5
624,8
1996
9,3
59,2
56,0
58,3
106,9
26,0
30,3
39,6
178,2
53,1
121,9
110,9
849,7
1997
14,8
24,4
55,5
83,8
64,7
9,3
39,0
81,9
13,2
100,5
23,1
57,2
567,4
1998
13,9
51,5
21,4
57,1
60,8
109,1
47,4
41,8
89,7
74,7
98,1
49,5
715,0
1999
22,6
70,8
17,6
80,1
61,6
44,7
132,6
37,2
81,2
85,0
56,0
92,6
782,0
2000
37,5
38,4
31,2
27,5
41,2
44,2
65,1
14,6
62,8
35,7
43,0
43,1
474,3
2001
23,1
54,0
16,5
145,0
85,3
77,8
88,4
14,2
111,5
40,8
55,6
29,9
742,1
min.
9,3
14,0
15,5
27,5
28,5
9,3
30,3
13,9
13,2
0,0
13,7
20,8
474,3
max
94,5
70,8
73,7
145
106,9
109,1
169,0
81,9
178,2
100,5
121,9
110,9
849,7
mean
33,5
41,2
37,6
63,7
58,6
53,8
76,1
38,8
72,0
53,8
59,0
55,6
637,7
Year
Table 2-8: Monthly precipitations distribution throughout measured at the CS Pec Month
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
18,5
41,7
46,2
107,9
64,8
28,3
110,2
33,2
38,9
87,5
136,7
10,9
724,8
1992
18,5
27,6
15,0
149,0
22,7
116,2
14,0
46,4
13,2
77,9
94,7
89,9
685,1
1993
17,6
10,0
128,1
54,0
40,2
66,0
19,6
9,3
81,9
92,1
123,2
109,4
751,4
1994
92,3
84,8
10,8
126,8
24,7
25,2
198,3
25,1
38,4
45,3
20,5
61,7
753,9
1995
87,4
40,6
92,1
67,0
68,5
37,8
122,8
101,6
97,5
0,3
38,0
115,5
869,1
1996
62,5
68,5
72,7
73,4
49,9
4,7
11,2
33,8
146,7
52,6
162,1
110,7
848,8
1997
40,2
43.6
55,7
69,6
35,6
14,8
25,5
31,6
15,7
128,8
49,9
99,7
610,7
1998
33,0
55,3
25,1
93,5
88,6
22,2
35,8
28,6
145,0
91,3
135,9
87,2
841,5
1999
17,6
10,0
10,8
54,0
22,7
4,7
11,2
9,3
13,2
0,3
20,5
10,9
610,7
2000
92,3
84,8
128,1
149,0
88,6
116,2
198,3
101,6
146,7
128,8
162,1
115,5
869,1
2001
46,3
46,9
55,7
92,7
49,4
39,4
67,2
38,7
72,2
72,0
95,1
85,6
760,7
min.
18,5
41,7
46,2
107,9
64,8
28,3
110,2
33,2
38,9
87,5
136,7
10,9
724,8
max
18,5
27,6
15,0
149,0
22,7
116,2
14,0
46,4
13,2
77,9
94,7
89,9
685,1
mean
17,6
10,0
128,1
54,0
40,2
66,0
19,6
9,3
81,9
92,1
123,2
109,4
751,4
Year
Table 2-9: Statistic data for daily precipitation and evapotranspiration in Northern Kosovo Region Prec.
Prec.
Prec.
PET
PET
PET
Best [mm]
Low [mm]
High [mm]
Best [mm]
Low [mm]
High [mm]
Mean
8,35
5,54
13,48
1,92
1,63
2,21
Min
10,00
0,00
2,25
0,35
0,01
0,66
Day
9| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Max
42,40
31,95
66,56
3,99
3,59
4,48
The results from Table 2-9 are presented in the graphic presentation in the figure below while Kosovo’s precipitation map is presented in Figure 2-3.
Figure 2-3: Average daily precipitation (red) & evapotranspiration (green) in the North Kosovo
Project area
Figure 2-4: Precipitation distribution of Kosovo
2.3.4 Solar radiation Kosovo has on average 2.066 hours with sun per year or approximately 5,7 hours per day. The highest insolation value is in Pristina with 2.140 hours for 1 year, while Peć with the smallest insolation value of 1.958 hours, Uroševac with 2.067 hours and Prizren with 2.099 hours. The maximum insolation in Kosovo occurs during July, while the lowest insolation occurs in December. 10| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Distribution of general solar radiation for Northern Kosovo is given below. Table 2-10: Sunshine Fractions and Sunny hours in North Kosovo Region Sun Fr.
Sun Fr.
Sun Fr.
Day Len.
Day Len.
Day Len.
Sun Hrs.
Sun Hrs.
Sun Hrs.
Best [%]
Low [%]
High [%]
Best [h]
Low [h]
High [h]
Best [h]
Low [h]
High [h]
Mean
30.333
22.273
38.923
2:09
3:57
3:01
4:55
Min
9.35
0
21.74
8:56
0:50
0:00
1:57
Max
54.5
50.05
60.9
5:15
7:45
7:07
8:30
Day
Throughout the year the sunshine hours are presented in the Figure 2-5.
Figure 2-5: Annual Sunshine Cycle in Northern Kosovo
2.3.5 Wind In Kosovo, the winds are blowing from all directions, but in different frequencies. In the Mitrovica region, there are 50-60 windy days per year. The most frequent winds are winds coming from the north and blowing to the southern quadrants. Even the region is protected by mountain range from the north, the Ibar valley withdraws large air mass from the north, rather than from the south where is open path for the air movements. Maximum wind velocity was recorded to be from the south-west, but the most of the winds were the second class winds. Table 2-11: Wind velocity distribution in m/s throughout the year in Zvecan Municipality Vapor
Vapor
Vapor
Wind
Wind
Wind
Best [hPa]
Low [hPa]
High [hPa]
Best [km/h]
Low [km/h]
High [km/h]
Mean
10,617
9,068
12,165
3,42
1,01
6,14
Min
4,98
4,01
5,84
2,25
0
4,53
Max
16,9
14,82
19,09
5,55
3,52
7,92
Day
Data collected on daily basis are presented in the graphic presentation in Figure 2-6. 11| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Figure 2-6: Wind velocity in Zvecan municipality (red) and water vapour pressure (green)
Based on the collected data some wind rose is presented in Figure 2-7.
Figure 2-7: Wind rose graph in Zvecan municipality (Orientation: vector Blowing to)
12| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
3
GENERAL REQUIREMENTS
3.1 SCOPE OF THE WORKS The table below summarizes the key requirements for the different facilities and for the appurtenant facilities: Table 3-1: General Scope of the Works Facilities
Key requirements
Remark
New landfill Savina Stena Cell A
Excavation and filling works Lining system Leachate collection system Landfill monitoring system Access road
Infrastructure
Fencing Entrance gate Internal roads Landscaping Supply lines, external and internal Monitoring system Fire fighting system Other auxiliary plants
Design + Construction
for the entire landfill up to the end of cell A for the entire landfill entrance area + cell A
Buildings
Reception building + weighbridge Administrativebuilding.Maintenace building
Auxiliary structures
Wheel washing unit Sampling area
Additional plants
Leachate treatment plant Emergency generator
Equipment
Front end loader Compactor
13| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
3.2 INTERFACES AND LIMITS OF SUPPLY The boundaries concerning utilities, access and disposal to Landfill Site are as follows:
3.2.1 Access Road A new access road will be constructed from the existing road to the entrance area of the new landfill The Contractor should follow the road line as shown in the drawings as for the road expropriation has taken place.
3.2.2 Power supply Network for electrical power supply exists in the existing road Raska- Mitrovica. The necessary extension of the network and the construction of a transformer station (if necessary), is not part of the works contract. It will be carried out by the Municipality of Zvecan.
3.2.3 Potable Water There will be no potable water on site. The water needs will be covered from the reservoir tank. As far as the water needsof the personnel concerns these will be covered by portable water bottles.
3.2.4 Phone Line The connection point for the telephone line is approx. 1.3 km away from the construction site.
14| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
4 4.1
LANDFILL GENERAL DESIGN PLAN
4.1.1 Design parameters and assumptions 4.1.1.1
Basin configuration
The landfill basin has been designed taking into consideration all the parameters regarding the legislation (EU and Kosovo) and also the particularities of the field. In that sense: Regarding the morphology, the field can be characterized by relatively strong relief with elevations from 500,00m to 660,00m. This is an advantage and disadvantage simultaneously. Advantage because there are grades that can be utilized for the development of the body of the waste and disadvantage because the existing slopes are steep and therefore extensive excavation are needed. Therefore, the main issue is to maximize the exploitation of the morphology of the field The natural grade of the field is 30-35% with direction from north to south to and 23% from east to west The excavations of the terrain should be carefully designed, so not to create problems with the underground waters if any. Given the morphology, of the field it is absolutely necessary to create perimetric slopes that: o
Maximize the value for money of the construction
o
Maximize the life time of the landfill
o
Give the opportunity to the operator to develop the landfill in stages
The grade of that slopes will not exceed the 2:3 for embankments and 1:1 for excavations Given the morphology of the field it is absolutely necessary to create a “basin” with perimetric slopes that will service the operation, and facilitate the “building - up” of the waste in a manner that the overall waste body is stable, with mild slopes and relatively low height The grade of the bottom of the basin, will be at least 5% and an effective leachate collection system is obtained The design of the waste anaglyph should be such that could be adjusted to the surrounding environment. The grade of the waste relief does not exceed the 1:3.
Flood works will be extensive in order to protect the cells from the run off and the river below For the calculation of the landfill capacity a compaction coefficient equal to 0.6 tn/m3 and percentage of the cover material equal to 15%
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4.1.1.2
Quantity and composition of waste to be deposited
The Sanitary Landfill (SL) will receive the followings according to Administrative Instruction no 10/2007 Article 8: i. ii.
Public wastes; Commercial and industrial, relevant with industrial housing waste which are known as nonhazardous waste;
For the study area there are not any data regarding the waste composition. Therefore we are going to use the results from the Report “Analysis of Municipal Solid Waste – Prishtina” March/April 2011 elaborated by GIZ.
Figure 4-1: Composition of the household waste in Prishtina, March 2011
In order to decide on the area required for a sanitary landfill lifetime of 20 years, the quantity of disposed waste needs to be calculated through these years. For the design, year 2015 has been selected as the starting year and year 2035 as the final year of the landfill’s operation. For the dimensioning of the landfill, a calculation scenario has been performed. The scenario is based on data given from the representatives of the Municipalities. The population of the severed area is app. 60.000 inhabitants (year 2015) the growth rate is 3%. The following table predicts the waste disposal and the actual volume required annually. For the preparation of this table, the following assumption has been accepted:
Average compaction rate in the landfill: 0,6 tn/m3 Percentage of the cover material in the waste volume: 15%
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Table 4-1: Quantity and volume of disposed waste, for the years 2015-2035
Waste production (tn/y) 13.140 13.534 13.940 14.358 14.789 15.233 15.690 16.161 16.645 17.145 17.659 18.189 18.734 19.297 19.875 20.472 21.086 21.718 22.370 23.041 23.732
Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035
Waste to landfill (m3/y) 21.900 22.557 23.234 23.931 24.649 25.388 26.150 26.934 27.742 28.575 29.432 30.315 31.224 32.161 33.126 34.119 35.143 36.197 37.283 38.402 39.554
SL volume/year (m3) 25.185,00 25.940,55 26.718,77 27.520,33 28.345,94 29.196,32 30.072,21 30.974,37 31.903,60 32.860,71 33.846,53 34.861,93 35.907,79 36.985,02 38.094,57 39.237,41 40.414,53 41.626,97 42.875,78 44.162,05 45.486,91
Total SL volume (m3) 25.185,00 51.125,55 77.844,32 105.364,65 133.710,59 162.906,90 192.979,11 223.953,48 255.857,09 288.717,80 322.564,33 357.426,26 393.334,05 430.319,07 468.413,65 507.651,06 548.065,59 589.692,55 632.568,33 676.730,38 722.217,29
The design should be able to handle the real maximum anticipated waste production, without overestimations. Therefore, the landfill’s maximum capacity must be over 288.717 m3 for the 10 year (Cell A) period and over 676.217,29 m3 for the 20 year period (Cell A+ Cell B) The construction refers in a cell with 10 years lifetime, but the infrastructures will be for the entire lifetime of the site i.e more than 20 years.
4.1.2 Design philosophy 4.1.2.1
Basin configuration
In order to achieve the above mentioned, an effort should be made to exploit the morphology of the field. The following should be combined:
The basin topography. Three elements are included within the term ‘basin topography’: elevation, basin grades and grade direction. o
Elevation: Several factors affect the elevation of the basin:
The depth of the groundwater table limits the basin elevation (in other 17| P a g e
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words the depth of the excavation works)
The excavation depth has to be great enough to a) achieve the desirable capacity and b) generate adequate cover material for avoiding excess soil quantities (if the excavated soil is suitable).
o
Basin grades: One of the main goals of the basin grades is to prevent leachate accumulation at any point of the landfill. To accomplish this, basin grades should be such so that leachate flows freely inside the collection pipes, to some collection points. Therefore, these grades must be high enough to prevent leachate accumulation, yet they cannot be too steep as a stability problem may be created, especially when there is a composite liner consisting of compacted clay and an HDPE geomembrane. The basin grades, finally, should be such so that leachate drains properly throughout the lifetime of the landfill. Consolidation, which occurs as water is squeezed from between soil particles, can occur as landfill is filled. As the site fills up with waste and cover material, the underlying soils may consolidate, disrupting the basin slope element. It should also be noted that base grades affect the volume that will be excavated and the average base elevation
o
Grades direction: The grades direction of the basin depends on where the leachate can be most effectively collected. Two main options exist. First, to collect the leachate at the perimeter of the landfill and second to establish collection points at the internal area of the landfill. The first option seems to be more appropriate on a long - term basis, due to better utilization of available volume, while the second option seems easier and less expensive (at least during construction phase).
The depth of the groundwater table. Based on the literature search that has conducted it appears to be no problem with any groundwater table in the study area. In any case the excavations will be of minimum so to avoid any adverse situations and to eliminate the cost excavations also.
The first cell of the new landfill will be developed in one phase. In the future (after 7-8 years) a second cell will be constructed and the landfill will have a total capacity of more than 20 years. With this design every cell has the potentiality: To work discernible, in terms of the waste deposition To reduce the amount of the produced leachate i.e every cell / subcell after the end of its operation will be temporarily closed, so the rain fall cannot enter the waste body The basin of the landfill it is proposed to be allocated in the south-western part of the site.
4.1.2.2
Lining System
The liner system must restrict leakage to acceptable limits through a combination of an effective leachate collection and removal system and a suitably impervious seepage barrier. To assure
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proper performance over the long life of the landfill, a chemical, biological and mechanical compatibility between the several components is required. The selection of the appropriate type of liners is based on: o
The type of waste to be disposed of
o
The availability of materials in the area
o
The requirements of the legislation
According to the National legislation Administrative Instruction (AI) No. 01/2009 on Conditions for selecting the location of the waste storage construction, the landfill base and the sideslopes will consist of a mineral layer, which satisfies permeability and thickness requirements with a combined effect in terms of protection of groundwater and surface water at least equivalent with k ≤ 1.0 x 10-9 m/s, thickness ≥ 1.0 m. In case that the above conditions are not fulfilled in the natural situation, an artificial soil barrier shall be constructed. This barrier consists of clay-sized soil and shall have a thickness of at least 0.5 m thickness and a minimum coefficient of permeability of 10-9m/sec, as required by Kosovar regulation for non-hazardous waste landfilling. According to Article 16 of the AI No. 01/2009: geomembranes for drainage isolation should be sustainable and should fulfil the following conditions: o
Minimal thickness 2.5mm, 310g/m2 geotextile 2.5 mm HDPE,
o
Extension force (elasticity) in temperatures until 230oC,>=400N,
o
Maximal extension during allurement loading till 5%,
o
Selvage strength between welding belts should be at least 90 % of strengths base material;
o
To interrupt the process of plant implantation and to resist against gnawers.
from
The drainage coverings with minimal thickness of 0.50m,with stone metric-granule comprises and with dimensions of 16-32mm; o
The drainage covering surfaces should be designed and constructed with a slope of l%.
The following table presents the basic requirements for bottom lining as well as the basin design as they are included in the relevant Kosovar legislation and according to the experience of the experts. Table 4-2: Main specifications used for bottom lining – basin design
Lining specifications Natural geological barrier – permeability Natural geological barrier – layer thickness Artificial geological barrier – permeability
< 10-9 m/s > 1.00m < 10-9m/s 19| P a g e
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Lining specifications Artificial geological barrier – layer thickness Drainage layer – permeability Drainage layer – layer thickness Geomembrane – permeability Geomembrane – layer thickness Basin design Basin grade (longitudinal) Basin grade (transversal)
4.1.2.3
> 0,50m < 10-3m/s > 0.50m < 10-9m/s > 2,5mm >1% >3%
Leachate Collection System
For the calculation of the leachate drainage, collection and treatment system, the official meteorological data, time series of 10 years will be used. When it comes to the design of the leachate collection system (LCS) the simpler is the better. The LCS can be designed either as passive or active. Passive systems work by themselves. Gravity causes any leachate generated in the landfill to flow downward, out of the landfill and direct it to a collection point. There are no valves to open or pumps to fail. On the other hand, active systems have advantages like: a) controlled leachate supply to the wastewater treatment plant, b) integrated maintenance of the entire system because it can be controlled outside the waste body. The principles of leachate collection system that rule the proposed design are: The input amount of rainwater should be reduced as much as possible. Leachate collection system is designed in accordance with the surface water management, as the correlation between them is strong. Trenches parallel with the footprint of the landfill will be developed in order to prohibit the runoff into the landfill’s body. The collection and drainage system should ensure long-term collection of the total quantity of leachate and exclude any admixture with rainwater. The system for leachate management was chosen upon the following requirements:
not to cause damage, deformities or shifts in the isolation system during its placement
the pipes should be hydraulically efficient and should withstand chemical, industrial and physical burdens, not only during the phase of operation, but at the phase of the landfill aftercare, as well
the hydraulic height of leachate should not exceed 50 cm above the geomembrane.
In the proposed design, leachate flows due to gravity from the various points of the landfill basin and slopes to the collection pipes. According to AI No. 01/2009 Article 17 the min. diameter of the pipe is 300mm.
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4.1.2.4
Leachate treatment
Leachate contains: Suspended solids Soluble waste components Soluble decomposition products Microbes Discharge of this liquid to surface and underground water is prohibited by legislation. Most of leachate components have the potential to be toxic and: Cause death of river life directly (toxins, BOD5) Cause death of river life indirectly (eutrophication) Contaminate drinking water Fe(OH)3 precipitates and clogs river Kills vegetation Pathogens According to the Administrative Instruction 10/2007 on waste landfills management in ANNEX I it is mentioned:
Maximal allowed concentration on discharging filtration from landfill Parameter Value of pH
Allowed norms 4-13
Organic components of carbon
up 200 mg/l
Arsenic
up 1.0 mg/l
Lead
up 2.0 mg/l
Cadmium
up 0.5 mg/l
Chrome
up 0.5 mg/l
Copper
up 10.0 mg/l
Nickel
up 2.0 mg/l
Zinc
up 10.0 mg/l
Mercury
up 0.1 mg/l
Phenol
up 10.0 mg/l
Ammonia
up 1.0 mg/l
Fluorine
up 50 mg/l
Chlorine
up 10000.0 mg/l
Cyanic
up 1.0 mg/l
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Parameter
Allowed norms
Nitrates
up 30.0 mg/l
Sulfates
up 5000.0 mg/l
Haloids
up 3.0 mg/l
Residue after evaporation Electricity conductive
up to 6% mass Up to 500000ms/cm (micro second)
In this respect a leachate treatment plant that assures the reaching of the aforementioned limit values is designed. 4.1.2.5
Biogas management
Biogas production and especially methane (CH4) is a result of the biodegradation procedure. Comparing the environmental impacts of the landfill, methane represents a source of environmental impact off-site that could, during the restoration period, cause many problems, similar to the operation period. There are a lot of Gaussian models that could describe the impacts of methane in the surrounding area. Therefore the biogas generation depends on the ratio of the different waste types entering into the landfill. In this respect a methane management system has to minimize the environmental impacts. The maximum biogas quantity from cell A is observed in year 2025 as it presented further down in this study. For the collection of biogas vertical collection wells (boreholes) will be constructed at the end of the operation time of the Cell A, when waste has reached final height. The system of vertical boreholes is proposed for the following reasons: It is easier to construct and presents the less chances of damages during operation It is a system that ensures low levels of oxygen penetration, thus methane concentrations are high (required in case a future utilization unit is installed) It gives the opportunity of gradual construction, each time to the parts of the landfill that reach final waste heights It allows for local adjustments and control of the system, as well as of monitoring of biogas quantity and quality The landfill gas management system shall consist out of the following:
Vertical collection wells (boreholes) Horizontal piping network Biogas Collection Stations Condensate traps system Blower and flare unit 22| P a g e
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According to AI No. 01/2009 Article 18 the min. diameter of the pipe is 300mm. 4.1.2.6
Environmental monitoring
The monitoring system, based on the requirements of the Kosovar and EU legislation, will consist of: Leachate monitoring system Groundwater monitoring system Surface water monitoring system Biogas monitoring system Settlements monitoring system Part of the overall monitoring system is also a series of parameters, which have a significant role in organizing and monitoring the various processes and operations of the landfill. These parameters are the following: Meteorological data Volume and composition of the incoming waste Volume and composition of the incoming soil material Monitoring of all the supportive works and registering of all their problems that affect the proper operation of the total plant. All the data collected from the monitoring systems should be kept on-site in appropriately organized records. 4.1.2.7
Utilities and structures
The proper operation of the SL depends on the right installation of utilities and structures. The entire necessary infrastructure for the appropriate operation of the SL has been included, namely: Main entrance - fencing Weighbridge building Weighbridge Sampling area Administration building
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Maintenance building Open parking for personnel and visitors Tire washing system Internal Roads Flood protection works Fire Protection zone in the perimeter of the landfill Fire fighting system Electrical system Green area Access Road
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4.2
EARTH WORKS
Setting up the Savina Stena organized sanitary landfill (SL), includes the construction of a series of infrastructure that is required for the proper operation of the landfill. All the configurations have been decided based on the following principles (having in mind the slopes of the terrain): Easy leachate collection, avoiding mixture with the rain water Easy accessibility of the garbage trucks to the bottom of the basin Construction of a perimeter trench for runoff of the rain water Technical works for flood protection The height of the final waste volume should not exceed by far the existing topography According to the landfill capacity mentioned in the previous section the net landfill disposal capacity for the first cell is at least 290.000 m3. According to the waste quantity that will be disposed in the landfill as presented in Table 3-1, the landfill capacity is sufficient for more than 10 years. The SL design is based on the Landfill Directive 99/31/EC and the respective Kosovar legislation.
4.2.1 Excavations and filling works Top soil The top soil shall be stripped in working area including but not limited to buildings, landfill area, LTP, etc. according to the requirements and specifications provided in related sections of this Volume. Excavation Only Cell A shall be excavated in the scope of this contract. Clay/sand When the excavation has reached the designed base level, all excavated surfaces shall be compacted to the required density and inspected. In case any sub-standard materials are detected, these materials shall be replaced with suitable non-settling materials installed and compacted according to the requirements for filling. Filling Excavated material shall be stockpiled at a storage area or near the site as appointed by the Engineer /Employer. The material if is appropriate shall be utilized as non-settling fill in fillings under the bottom of the landfill lots or for construction of embankments and dikes.
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Filling in sub-soil for construction purposes (elevation of the lot bottom to designed base for polymer membrane or construction of dikes) must be performed by building in layers of maximum 0.25 m thickness. Storage of Excess Materials
Excess materials shall be stockpiled at a storage area at or near the site as appointed by the Engineer /Employer.
4.2.2 Cell A construction The existing the field~26ha, is enough for the development of the landfill for 20 years. In full development the landfill will consists of two cells, cell A and cell B. The bottom of the cell A has been configured in the shape of V. The side slopes inside the cell will be at least. 1:3. The grade of the basin is app. 4%-5% and it is uniform for the entire surface of the 1st cell. It is noted that in the future the 2nd phase of the landfill will be developed beside to the first cell in order to be able to receive wastes for an additional 10 years (overall the landfill lifetime will be approx 20 years). The surface of the second phase of the landfill will be approx 3 ha and the total capacity of both cells will be approx. 680.000 m3. For the cell A, which is under examination, app. 268.000m3 excavations and app.93.500 m3 banking up, will be required for the configuration of the area of the landfill and the utilities connected to it. The surface of the cell A will be about 3ha (2,92ha) and it will have a total capacity of approximately 350.000 m3, including the sealing and final cover volume, of which at least 290.000 m3 will be the disposal capacity. The lowest altitude of the cell (in absolute units) in the proposed design is +578m, while the highest altitude will be +606m.
4.3
CALCULATION OF CELL LIFETIME
According to the landfill capacity mentioned in the previous section the net landfill disposal capacity for the first cell is at least 290.000 m3. According to the waste quantity that will be disposed in the landfill as presented in Table 3-1, the landfill capacity is sufficient for more than 10 years.
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4.4
BOTTOM LINING CONSTRUCTION
4.4.1 Introduction The selection of the appropriate type of liners is based on: The type of waste to be disposed (municipal solid waste) The availability of materials in the area The hydrogeological conditions of the site. The liners were selected upon the following requirements: to keep the cells sealed from precipitation and surface water to be resistant to temperature of at least 70oC to seal the produced gas and leachate to be resistant to any sedimentations and erosions to be resistant to the effect of the microorganisms to be easy to install to be easy to check during both the construction and the operation to be easy to mend not to be of high expenditure The lining system of the new landfill includes (from the bottom to the top):
Compacted Clay liner
Geomembrane
Geotextile
Sand layer
Drainage layer (or equivalent)
4.4.2 Compacted Clay liner According to the legislation, the landfill base and the sideslopes will consist of a mineral layer, which satisfies permeability and thickness requirements with a combined effect in terms of protection of groundwater and surface water at least equivalent with k ≤ 1.0 x 10 -9 m/s, thickness ≥ 1.0 m. 27| P a g e
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In case that the above conditions are not fulfilled in the natural situation, an artificial soil barrier shall be constructed. This barrier consists of clay-sized soil and shall have a thickness of at least 0.5 m thickness and a minimum coefficient of permeability of 10-9m/sec, as required by Kosovar regulation for non-hazardous waste landfilling. In any case the bottom of the barrier system should also have a minimum distance of 1m to the ground water table position if such water table found. The permeability and thickness requirements are checked through the following equation:
H CC H NC 1m / 1x10 9 m / s 1x109 s k CC k NC
[1]
where ΗCC = thickness of compacted clay liner (m) kCC = permeability of compacted clay liner (m/sec) ΗNC = thickness of the natural clayey barrier up to groundwater surface (m) και kNC = permeability of the natural clayey barrier (m/sec). If these conditions are not fulfilled in the natural situation, an artificial hydrogeological barrier shall be constructed. This barrier can consist of clay or another material with equivalent properties and shall have a thickness of at least 0,5 m thickness as required by Kosovar regulation. The clay liner will be constructed as a compacted layer. To function as a liner, the clay must be kept moist. However, the following possible problems should be taken into consideration:
Clay liners are difficult to compact properly on a soft foundation (i.e. waste).
Compacted clay will tend to desiccate from above and/or below and crack unless protected adequately.
Differential settlement of underlying compressible waste will cause cracking in the compacted clay if tensile strains in the clay become excessive.
Compacted clay liners are difficult to repair if they are damaged.
Technical Specifications A geological barrier constructed as a built-in compacted clay layer consists of minimum 0.50 m thick compacted clay layer with a permeability coefficient of less than k = 1.0 x 10-9 m/s. The barrier may be constructed of clay or clayey soils excavated on the site or of suitable soils imported to the site from a borrow area not containing stones or rock fragments larger than 0.03 m. No new layer may be installed over an installed clay layer before the latter has been checked and approved by the supervising authority.
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All surfaces will be finalized at designed level for the base of the polymer membrane. The compaction shall be concluded using a smooth vibratory roller or equivalent plant, which ensures a smooth surface of the clay layer. The filling works shall be performed in such a manner, that the base-materials is not unacceptably hydrated from rain or surface water or dehydrated from evaporation. In any areas where claymaterials are unacceptably hydrated or dehydrated or otherwise do not comply with requirements, the materials shall be replaced with suitable materials. Visible stones or other particles larger than 0.10 m shall be removed from the surfaces during the works - if necessary manually. Immediately upon inspection, check and acceptance of the finished surface the surface shall be covered by the polymer-membrane. The minimum values f physical properties of clay material in order to achieve the permeability requirements, after the standard Proctor compaction are summarized in the following table: Table 4-3: Clay liner specifications Property Liquid limit, LL (%) Plasticity Index, PI (%) Clay content (particle diameter < 0,074 mm) (%) Clay content (particle diameter < 2 μm ) (%) Content of swelling clays (i.e. smectite, illite) (%) Sand content (%) Organic content (% κ.β.) Carbonate content (% κ.β.) Max diameter of gravel or cluster (mm)
Value 20 - 40, preferred 25 - 30 10 - 25 > 30, preferred 40 - 50 ≥20, preferred 20 - 25 >10 < 40 10-3 m/s. Execution of the works Before any installation of drainage materials on top of the polymer liner is commenced the Contractor shall set up a plan for the execution of the works to be approved by the Supervision Authority. The plan shall describe which plant and methodology the Contractor intends to utilize, ensuring that no damage is done to the liner system. No equipment is allowed to enter on top of the polymer liner without adequate protection of the liner against mechanical damage. Protection can be ensured by:
permitting the trucks bringing drainage material in to the cells at all times drive on a "dike" with a thickness no less than 1,0m between the wheels and the liner, or at protective plates of concrete or steel.
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permitting only vehicles and other machinery with belt-drive or low wheel pressure enter onto the installed drainage layer.
During installation works, it is not allowed to push the drainage using bulldozers or equivalent machinery that may cause tension in the polymer membrane. Drainage material shall be "rolled" or "laid" out using e.g. excavation machinery on belts or equivalent. When the drainage material has been installed excavations for e.g. installation of drainage pipes and filter material around the pipes may only be done manually, and all excavated trenches shall be visually inspected and approved by the Engineer before drain pipes are installed. The installation of filter material around drain pipes shall ensure the designed dimensions of the filter material.
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4.5
LEACHATE MANAGEMENT
4.5.1 Leachate generation - composition Leachate is produced in landfills, as water enters the waste volume, due to humidity, precipitation and/or rising groundwater level. Leachate contains suspended solids, soluble waste components, soluble decomposition products and microbes. The most of leachate components have the potential to be toxic and could cause the death of river life, directly (through toxins and BOD5) or indirectly (via eutrophication). They can also contaminate drinking water. Therefore, under no circumstances should the leachate be discharged to surface and underground water. Besides, the legislation is very strict concerning this matter. The composition of the leachate produced in a landfill, depends on the type, composition and age of waste, the degree of compression in landfills, etc. A typical composition of the leachates produced from domestic waste landfills are given in the table below. Table 4-6: Composition of produced leachates
Parameter BOD5 TOC COD Total Suspended Solids Organic nitrogen Ammonia nitrogen Nitrates Total phosphorus Orthophosphoric Alkalinity (CaCO3) pH Totalhardness(CaCO3) Calcium Magnesium Potassium Sodium Chlorine Sulphur Total iron
Concentration limits (mg/l) 2.000 – 30.000 15.000 – 20.000 3.000 – 45.000 200 – 1.000 10 – 600 10 – 800 5 – 40 1 – 70 1 – 50 1.000 – 10.000 5,3 – 8,5 300 – 10.000 200 – 3.000 50 – 1.500 200 – 2.000 200 – 2.000 100 – 3.000 100 – 3.000 50 – 600
Typical concentration (mg/l) 10.000 6.000 18.000 500 200 200 25 30 20 3.000 6 3.500 1.000 250 300 500 500 500 60
Experience has shown that the isolation of the base itself, without collection and removal of leachate, can ultimately cause more harm than good. Therefore, a collection and drainage system is essential, and is one of the most important stages in the construction of a landfill, as the lifetime of the isolation is largely dependent on this. The principles of leachate collection system that rule the proposed design are:
The input amount of rainwater should be reduced as much as possible. Leachate collection system is designed in accordance with the surface water management, as the correlation 36| P a g e
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between them is strong. Trenches parallel with the footprint of the landfill will be developed in order to prohibit the runoff into the landfill’s body.
The collection and drainage system should ensure long-term collection of the total quantity of leachate and exclude any admixture with rainwater.
The system for leachate management should be chosen upon the following requirements: not to cause damage, deformities or shifts in the isolation system during its placement the pipes should be hydraulically efficient and should withstand chemical, industrial and physical burdens, not only during the phase of operation, but at the phase of the landfill aftercare, as well (50 years, 40oC, waste density: 1,5 Mg/m3) free flow of leachate towards its collection tank should be enabled and leachate should be treated in a rather easy way the hydraulic height of leachate should not exceed 50 cm above the geomembrane. The selection of the most appropriate scheme should be based on the expected quantities of the produced leachate, which must be collected, removed and finally treated according to the suggested technique. For the determination of the volume, the rate of production and the qualitative composition of leachate, the following information were required:
the climatic conditions of the region (height and distribution of precipitation. temperature)
the qualitative composition of waste
the way of the sanitary landfill operation
the age of layers
4.5.2 Leachate production In this study, the quantity of leachate has been estimated for the following operation phases: Cell A in operation (10 years operation) Cell A filled To estimate the leachate production, initially the evapotranspiration had to be determined. The evapotranspiration (ET) presents the sum of the real water losses through the evaporation of soil and mold and the transpiration of the flora. Dynamic (potential) evapotranspiration (ETP) presents the evapotranspiration that could have occurred, if there was an excess of moisture on the relevant surfaces. For the calculation of the hydrological balance, the dynamic evapotranspiration is used.
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In this study, the determination of the potential evapotranspiration has been conducted using the Thornthwaite equation: ETP PE ( PE ) x x
DT 360
where: ETP = PE = corrected potential evapotranspiration (mm /month) (PE)x = average potential evapotranspiration (mm/month) ( PE ) 16 x( x
10 xTi a ) J
where: Ti = mean monthly air temperature J = annual heat index a = surface flow coefficient
J
J
i
where: Ji = monthly heat index Ji 0,09 x Ti
3
a 0,016 J 0.5
DT 0.1217 P 360 where: P = the average percentage of hours of daylight for each month of the year. For latitudes between 33o and 47o north of Equator. The average hours of daytime for each month of the year were calculated using linear interpolation, based on the relevant hydrological table. The mean monthly precipitation and the mean monthly temperature were calculated, given data for from the nearest Meteorological Station. Having calculated the evapotranspiration, produced leachate is easy to estimate upon the hydrological balance.
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L P R E (axW )
Where: L = leachate P = precipitation R = surface flow E = real evapotransporation a = absorbability of waste (defined as the quantity of water the waste can withhold reduced by the quantity of water produced during biodegradation reactions) W = weight of waste entering the landfill For the hydrological balance implementation, the following assumptions have been made. There is no leakage towards the groundwater table, due to the isolation of the bottom of the active basin. There is no rainwater inflow from the wider basin, due to the construction of suitable ditches for the rainwater outflow, which direct the surface flow away from the waste body. The climatic data used for the estimation of leachate quantities are shown in the following table. Table 4-7: Climatic data (Monthly precipitations distribution throughout measured at the CS Kopaonik) Month
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
annual
1991
24,5
46,5
74
118,5
127,8
62,1
187,8
88
43,8
102,7
85,5
66
1027,2
1992
26,5
116,6
62,3
86,6
17,2
318,7
71,7
32,2
10,3
86,2
133,2
60,7
1000,2
1993
33,3
31,7
96,2
65,9
96,3
64,2
45,9
24,9
92,3
30,3
52,5
103,4
736,9
1994
75,2
29,1
55,5
110.7
66,9
107,6
128,6
48,2
77,4
75,5
31,6
51,4
857,7
1995
128,9
58,9
102,4
118,4
169
96,2
76,4
120,1
139,2
2,5
94,9
77,8
1184,7
1996
19,5
52,4
81,9
104,6
122,6
59,2
26,2
99,3
237,9
91,4
118,2
88,9
1102,1
1997
17,2
43,8
82
140,8
108,7
37,7
114
174,5
31.9
97,8
19,4
69,1
936,9
1998
32,3
30,3
76,4
78,8
98,3
86,6
50,2
68
148,8
115,8
69,9
57,7
913,1
1999
41,4
95,8
31,1
114
85,7
128,5
187,4
28,6
67,7
52,7
102,6
107,6
1043,1
2000
80,2
80,6
101
85
70,5
68,3
54.7
10,5
129,5
32,9
38,4
55,1
806,7
2001
31,5
67,4
52,3
152,7
151,9
200,3
84,3
84,4
232,3
17,9
115,7
39,7
1230,4
min.
17,2
29,1
31,1
65,9
17,2
37,7
26,2
10,5
10,3
2,5
19,4
39,7
736,9
max
128,9
116,6
102,4
152,7
169
318,7
187,8
174,5
237,9
115,8
133,2
107,6
1230,4
mean
46,4
59,4
74,1
106,5
101,4
111,8
97,3
70,8
117,9
64,2
78,4
70,7
985,4
Year
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DESIGN OF SAVINA STENA SANITARY LANDFILL
Table 4-8: Temperature data from the surrounding meteorological stations in the area Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Year
Mean Temperature 1
0,4
3
6,5
11,1
15,6
19,3
21,2
21,1
17,6
12,3
7,6
2,7
11,5
2
0,4
3
6
9,6
14,8
18,5
20,2
19,8
16
10,8
6
1,6
10,5
3
0,5
3
6,1
10,8
15,3
19,1
21,2
21,5
17,3
12
7,1
2,7
11,4
4
-0,4
2
5,5
10,1
14,8
18,7
20,3
20,6
16,7
11,3
6,5
1,7
10,7
5
0,6
3,7
6,5
10,6
15,8
19,1
21
20,6
17
11,8
7
11,8
12,1
6
-0,5
1,2
5
11,3
15,8
19,2
21,5
21,2
17,8
12,1
7
3
11,2
7
-0,7
2,2
5,6
10,1
15
18,3
20,2
20
16,6
11,5
7,1
1,6
10,6
8
0,4
3
7,5
11,6
16,2
19,3
21,2
21,6
18,2
12,8
6,3
2,5
11,7
9
-1,8
0,1
-3,3
5,9
10
15
19,3
15,8
17,5
9
4,5
0,8
7,7
10
1,5
4,3
7
11
16,2
19,8
21,6
21,2
17,6
12,1
7,8
2,7
11,9
AVER
0,04
2,55
5,24
10,21
14,95
18,63
20,77
20,34
17,23
11,57
6,69
3,11
10,93
The results of the leachate estimation are shown in following tables and figure.
40| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL Table 4-9: Leachate production when cell is in operation (mm/month) J
F
M
A
M
J
J
A
S
O
N
D
Annual
46,40
59,40
74,10
106,50
101,40
111,80
97,30
70,80
117,90
64,20
78,40
70,70
998,90
Temperature ( C)
0,04
2,55
5,24
10,21
14,95
18,63
20,77
20,34
17,23
11,57
6,69
3,11
10,94
Monthly heat index (Ji)
0,00
0,37
1,08
2,94
5,20
7,24
8,52
8,26
6,44
3,54
1,56
0,49
Annually heat index (J)
45,63
Precipitation (mm/month) o
Surface flow coefficient (a)
1,23
Average potential evapotranspiration (PE)x (mm/month) Adjusted potential evapotranspiration (ETP)(mm /month) Surface runoff coefficiency (%)
0,05
7,82
18,97
43,09
68,88
90,29
103,22
100,59
82,02
50,26
25,62
9,99
600,79
0,04
6,31
19,18
47,26
85,29
112,77
130,52
118,05
54,90
46,99
20,51
7,69
649,52
53,09
54,92
59,24
16,11
0,00
0,00
0,00
63,00
17,21
57,89
63,01
430,82
Infiltration (mm/month)
0,00 46,36
Table 4-10: Leachate production when cell is under rehabilitation (mm/month) J
F
M
A
M
J
J
A
S
O
N
D
Annual
46,40
59,40
74,10
106,50
101,40
111,80
97,30
70,80
117,90
64,20
78,40
70,70
998,90
Temperature ( C)
0,04
2,55
5,24
10,21
14,95
18,63
20,77
20,34
17,23
11,57
6,69
3,11
10,94
Monthly heat index (Ji)
0,00
0,37
1,08
2,94
5,20
7,24
8,52
8,26
6,44
3,54
1,56
0,49
0,05
7,82
18,97
43,09
68,88
90,29
103,22
100,59
82,02
50,26
25,62
9,99
600,79
0,04
6,31
19,18
47,26
85,29
112,77
130,52
118,05
54,90
46,99
20,51
7,69
649,52
15,93
16,47
17,77
4,83
0,00
0,00
0,00
18,90
5,16
17,37
18,90
129,25
Precipitation (mm/month) o
Annually heat index (J)
45,63
Surface flow coefficient (a)
1,23
Average potential evapotranspiration (PE)x (mm/month) Adjusted potential evapotranspiration (ETP)(mm /month) Surface runoff coefficiency (%)
Infiltration (mm/month)
70,00 13,91
41| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL Table 4-11: Monthly average leachate production (m3/month)
Cell A in operation Cell A filled
JAN 1.390,87
FEB 1.592,59
MAR 1.647,47
APR 1.777,24
MAY 483,18
JUN 289,91
JUL 173,95
AUG 104,37
SEP 1.889,97
OCT 516,36
NOV 1.736,61
DEC 1.890,31
417,26
477,78
494,24
533,17
144,96
86,97
52,18
31,31
566,99
154,91
520,98
567,09
Table 4-12: Daily average leachate production (m3/day)
Cell A in operation Cell A filled
JAN 46,36
FEB 53,09
MAR 54,92
APR 59,24
MAY 16,11
JUN 9,66
JUL 5,80
AUG 3,48
SEP 63,00
OCT 17,21
NOV 57,89
DEC 63,01
13,91
15,93
16,47
17,77
4,83
2,90
1,74
1,04
18,90
5,16
17,37
18,90
Table 4-13: Hourly average leachate production (m3/hour)
Cell A in operation Cell A filled
JAN 1,93
FEB 2,21
MAR 2,29
APR 2,47
MAY 0,67
JUN 0,40
JUL 0,24
AUG 0,14
SEP 2,62
OCT 0,72
NOV 2,41
DEC 2,63
0,58
0,66
0,69
0,74
0,20
0,12
0,07
0,04
0,79
0,22
0,72
0,79
42| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Cell A in operation
Cell A filled
Daily production of leachate
43| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
From the above, the following can be concluded: The leachate production during the operation cell A is expected to be between 3,48 and 63,01 m3/day The leachate production when cell A is filled is expected to be between 1,04 and 18.9 m3/day
4.5.3 Leachate collection The leachate collection system can be either passive or active. In passive systems, the produces leachate flow downward (due to gravity), out of the landfill and direct it to a collection point. There are no valves to open or pumps to fail. On the other hand, active systems have advantages like: a) controlled leachate supply to the wastewater treatment plant, b) integrated maintenance of the entire system because it can be controlled outside the waste body. The principles of leachate collection system that rule the proposed design are:
The input amount of rainwater should be reduced as much as possible. Leachate collection system is designed in accordance with the surface water management, as the correlation between them is strong. In order to prohibit the runoff into landfill’s body a number of works will take place (see par. 4.8).
The collection and drainage system should ensure long-term collection of the total quantity of leachate and exclude any admixture with rainwater.
The system for leachate management was chosen upon the following requirements: o
not to cause damage, deformities or shifts in the isolation system during its placement
o
the pipes should be hydraulically efficient and should withstand chemical, industrial and physical burdens, not only during the phase of operation, but at the phase of the landfill aftercare, as well
o
the hydraulic height of leachate should not exceed 50 cm above the geomembrane.
In the proposed design, leachate flows due to gravity from the various points of the landfill basin and slopes to the collection pipes. In the basin one deep point is designed in the south part of the cell, from which a non-perforatedpipe pierces the bounding embankment and leads the leachate through gravity to the LTP. The basin of the landfill is shaped to have slopes at least 33% transversal on the drainage pipe network and about 4-5% longitudinal. Highest depth points are placed outside sealed area. Each collection pipe, again by the use of gravity, leads collected leachate outside of the landfill to the corresponding collection sump.
44| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
The collection of leachate shall be facilitated by pipes, which will be positioned having an adequate inclination to achieve effective flow of leachate to the lower level of the basin, installed within the drainage layer in a special surface formation of the deposition basin. The collection pipes shall be made of HDPE perforate by 2/3 of their diameter and shall have a nominal diameter D = 315 mm. The diameter has been selected taking into consideration precipitation data of the area, as well as the basin of the landfill.The pipes installed into the gravel zone. For the installation of the leachate collection pipes a special topical formation of the basin is constructed. The pipes will be placed in the bottom of the basin, according to the proposed design. At the bottom of cell four (4) pipes will be placed. The produced leachate will be collected from the respective pipes. In the basin one deep point is designed in the south part of the cell, from whicha non-perforated pipe pierces the bounding embankment and leads the leachate through gravity to the LTP. The non-perforated pipe shall be made of HDPE and shall have a nominal diameter D = 315 mm, and will lead the collected leachate through the embankment to the collection sump. Uphill the collection sump there will be a gate-valve sump in order to cut off flow when the pipe cleaning is taking place. The collection sump are made of concrete. The dimensions of the sump will be 1,5x1,5m. 4.5.3.1 I.
Dimensioning of leachate drainage pipes Discharge estimation method
The hydrological calculations are made for a return period of 10 years. The calculation of the maximum leachate production has to be made for the correct dimensioning of the leachate collection system. The calculation of the maximum leachate production is made by using the rational method: Q= c x i x Α Where:
II.
c: runoff coefficient
i: rainfall intensity in the time of concentration (m/s)
Α: area of catchment’s basin (m2) Concentration time
The rainfall duration used for the calculation of critical intensity corresponds to the concentration time of the catchment basin. For the calculation of the concentration time the Kirpich equation is used: 45| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
t c = 0,1947 x L0,77 x S (−0,385) Where: Tc: time of concentration (min) L: longest watercourse length (m) S: slope between the highest point in the catchment and the catchment
III.
Collection system design – Hydraulic calculations
For the dimensioning of the pipes the Manning formula was used assuming that the continuity assumption is valid. Q=AxV
V
1 3 2 R S n
Where:
Q
= discharge (m3/s)
A
= “wet” area (m2)
V
= velocity (m/s)
n
= Manning coefficient
R
= hydraulic radius (m)
S
= slope
According to the proposed design, at the bottom of cell A four pipes (P1,P2,P3,P4) will be placed. The sizing of pipes is shown in the table below. Table 4-14: Sizing of leachate collection pipes
Characteristics Outer Diameter (mm Inner Diameter (mm) )@10Atm Starting Height (m) Finishing Height (m) Length (m)
Pipes
Ρ1
Ρ2
Ρ3
Ρ4
315 255.6 585,00
315 255.6 579,00
315 255.6 585,00
315 255.6 579,00
579,00 157,00
577,80 22,00
579,00 157,00
577,80 22,00 46| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Characteristics Inclination (%) Flow (m3/sec) Velocity (m/sec) Wetted Perimeter (m) Wetted Radius (m) Perforation Safe factor
Pipes
Ρ1
Ρ2
Ρ3
Ρ4
3,8217% 0,6044 4,4577 0,948 0,1431 2/3 9,59
5,4545% 0,7220 5,3255 0,948 0,1431 2/3 15,92
3,8217% 0,6044 4,4577 0,948 0,1431 2/3 10,17
5,4545% 0,7220 5,3555 0,948 0,1431 2/3 16,00
As shown in the above calculations, the velocity within the pipes is much bigger than 0.4 m/sec which is the down limit so that no deposit of sediments within the pipelines occurs. In addition all the pipes have a safety factor ranging from 9,59 up to 16,00.
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DESIGN OF SAVINA STENA SANITARY LANDFILL
4.6
LEACHATE TREATMENT
4.6.1 Introduction For an integrated leachate management, normally more than one treatment methods are required. These methods aim at achieving the demanded final effluent quality. Combined systems are the most commendable methodology for leachate treatment. As main treatment methods, biological methods and/or physicochemical methods are used, such as: Aerobic biological treatment Anaerobic treatment systems Chemical oxidation Membrane aided treatment (reverse osmosis) Evaporation (closed or open system). Complementary, and if required by the effluent requirements, purification systems can be used as a first or final stage of treatment (before the final disposal), such as: Physical sedimentation Chemical flocculation / sedimentation and infiltration in a sand filter Adsorption in an active carbon filter Oxidation with ozone (ozonosis) Ammonia removal in an absorption column Generally, for leachate treatment, a main method (from the ones previously mentioned) is always selected, depending on the age of leachate (if it is “fresh” or “old”). Additionally, a secondary method can be selected if required. In rare cases, two main treatment methods can be combined, but this involves high cost, and is implemented only when it comes to leachate of specific characteristics. The selection criteria for the treatment system are: 1. the characteristics of leachate to be treated 2. the characteristics of the treated leachate based on the final recipient 3. progress of the landfill operation through the years 4. costs of investment and operation 48| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Concerning the 1st criterion, the basic characteristics of the leachate to be treated are approximately anticipated to be: BOD5 = 13.000 mg/l COD = 22.000 mg/l SS = 1.200 mg/l TN = 2.000 mg/l TP = 6 mg/l These characteristics represent the worst possible case, where mixed waste will be disposed to the landfill. Additionally, the wastewater from the material recycling facility, the composting plant, the staff from this facility as well as the wastewater from the tier washing, will be led to the leachate treatment plant. Concerning the 2nd criterion, the final recipient of the treated leachate will be the waste anaglyph or in natural recipients. Therefore, the quality of the treated leachate is what it refers to the national legislation and additional. For the Savina Stena SL the effluent characteristics are as follow :
COD 250 mg/l
ΒΟD5 50 mg/l
Concerning the 3rd criterion, there are two basic parameters that fluctuate during the operation of the landfill: the quantity and composition of the incoming solid waste the quantity and quality of the produced leachate The incoming quantity of waste will be changing over time, because of the implementation of the solid waste management plan, which foresees the treatment of waste. This will lead not only to a gradual reduction of the quantity of waste entering the landfill, but also to a drastic change in the waste composition. Basic characteristic of the last one is the decrease in the organic load as well as its stabilization or its inactivation. As a result, the quality of the produced leachate is expected to change, provided that the residues from treatment processes have a different behaviour in their burying and their interaction with the incoming water. Also, the sequential design of the landfill, using different cells, implies a big range in leachate production. It is obvious that the selection of the treatment system for the landfill must be characterized by a big “elasticity” concerning the quantities and the quality of leachate. 49| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Finally, concerning the 4th criterion, the capital and operational cost is a parameter to be examined in any plant. The selection of the management system should be a combination of the maximum environmental efficiency with the minimum economic cost. According to the previous criteria, further down a leachate treatment plant is proposed for the Savina Stena Landfill
4.6.2 Leachate treatment plant of Savina Stena Landfill The proposed leachate treatment plant has to ensure that the effluent will have the quality to be discharged in natural recipients according to the requirement of the legislation and the reduction of the concentration values for the following indices:
solid materials in suspension
oxygen chemical consumption
oxygen biochemical consumption
ammonia
nitrates
sulphurs
chlorates
heavy metals.
The applied treatment technique combination has to ensure the removal of the following pollutants:
ammoniac nitrogen
bio-degradable and non-degradable organic compounds
chlorinate organic compounds
mineral salts.
Leachate treatment is attained with the help of special equipment, modular, which are selected as a function of the each case specific. The typical characteristics of the input of the leachate treatment plant are:
50| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL Table 4-15: Typical characteristics of leachate input to treatment plant
Landfill Leachates Q BOD5 COD SS TN TP Landfill Staff Q BOD5 SS TN TP Tire washing wastewater Q BOD5 COD SS TN TP
= = = = = =
63,01 m3/d 13.000 mg/l 22.000 mg/l 1.200 mg/l 2.000 mg/l 6 mg/l
= = = = =
1,00 m3/d 280,00 mg/l 240,00 mg/l 25,00 mg/l 5,00 mg/l
= = = = = =
1,00 m3/d 2.000,00 mg/l 4.000,00 mg/l 500,00 mg/l 150,00 mg/l 1,00 mg/l
The requirements for the quality of the effluent are:
COD 250 mg/l
ΒΟD5 50 mg/l
A system based on Sequence Batch Reactors (SBR) is selected. SBR systems have been systematically used for leachate treatment and they offer various benefits such as minimal space requirements, ease of management and possibility of modifications during trial phases through on-line control of the treatment strategy. Main advantages of SBR process are: 1) Simple construction, 2) Plant can fit into almost any shape, 3) Flow through plants requires regular shaped sites, 4) Fewer channels and pipe work, 5) Easily scalable, and 6) Can be adapted to both nitrification and denitrification. However, there are some disadvantages which are considered minor like a higher level of sophistication is required (compared to conventional systems) and a higher level of preservation (compared to conventional systems) associated with more sophisticated controls, automated switches, and automated valves. Finally, sometimes there is potential requirement for equalization after the SBR, depending on the downstream processes. The proposed leachate treatment plant is presented below.
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DESIGN OF SAVINA STENA SANITARY LANDFILL
Figure 4-1: Leachate treatment flowchart
The leachate collected at the equalization tank will be pumped to the entrance of the SBR well. In this point, the necessary quantity of nutrients is added in order to facilitate the biological process. The enriched leachate will overflow towards the SBR1 where the biological reactions and transformations will take place. More specifically, with the support of aeration and stirring, biodegradation phenomena (nitrification / denitrification of organic fraction) will take place inside the SBR1 unit. At the same time, sedimentation of suspended solids will also take place creating a sludge layer at the bottom of the SBR1. The output of SBR1 is driven to SBR2 for further treatment. Similar phenomena take place in SBR2 (biodegradation, sedimentation). The output of SBR2 is collected to a well and form there it is sent for disinfection. From both SBRs the biological sludge created is moved to another well where sludge pumps will transfer it to the sludge thickener. With this treatment the required effluent characteristics will be achieved. 4.6.2.1
Design parameters
The main design characteristics are presented in Table below: Table 4-16: Quantity& Quality of effluent leachate
A.
Quantity
B.
Quality
unit
Value
M3/d
65
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DESIGN OF SAVINA STENA SANITARY LANDFILL
4.6.2.2
unit
Value
°C
12-20
1
Temperature
2
pH
3
BOD5
mg/l
13.000
4
COD
mg/l
22.000
5
SS
mg/l
1.200
6
ΤΚΝ
mg/l
2.000
7
ΤP
mg/l
6
6,5-8,5
SBR Process description
The operation of an SBR is based on a fill-and-draw principle, which consists of five steps—fill, react, settle, decant, and idle. These steps can be altered for different operational applications and they are presented at Figure 4-2. Fill During the fill phase, the basin receives influent wastewater. The influent brings food to the microbes in the activated sludge, creating an environment for biochemical reactions to take place. Mixing and aeration can be varied during the fill phase to create the following three different scenarios: Static Fill – Under a static-fill scenario, there is no mixing or aeration while the influent wastewater is entering the tank. Static fill is used during the initial start-up phase of a facility, at plants that do not need to nitrify or denitrify, and during low- flow periods to save power. Because the mixers and aerators remain off, this scenario has an energy-savings component. Mixed Fill – Under a mixed-fill scenario, mechanical mixers are active, but the aerators remain off. The mixing action produces a uniform blend of influent wastewater and biomass. Because there is no aeration, an anoxic condition is present, which promotes denitrification. Anaerobic conditions can also be achieved during the mixed-fill phase. Under anaerobic conditions the biomass undergoes a release of phosphorous. This release is reabsorbed by the biomass once aerobic conditions are reestablished. This phosphorous release will not happen with anoxic conditions. Aerated Fill – Under an aerated-fill scenario, both the aerators and the mechanical- mixing unit are activated. The contents of the basin are aerated to convert the anoxic or anaerobic zone over to an aerobic zone. No adjustments to the aerated-fill cycle are needed to reduce organics and achieve nitrification. However, to achieve denitrification, it is necessary to switch the oxygen off to promote anoxic conditions for denitrification. By switching the oxygen on and off during this phase with the blowers, oxic and anoxic conditions are created, allowing for nitrification and denitrification. Dissolved oxygen (DO) should be monitored during this phase so it does not go over 0.2 mg/L. This ensures that an anoxic condition will occur during the idle phase 53| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
Figure 4-2: SBR cycles
React This phase allows for further reduction or "polishing" of wastewater parameters. During this phase, no wastewater enters the basin and the mechanical mixing and aeration units are on. Because there are no additional volume and organic loadings, the rate of organic removal increases dramatically. Most of the carbonaceous BOD removal occurs in the react phase. Further nitrification occurs by allowing the mixing and aeration to continue—the majority of denitrification takes place in the mixed-fill phase. The phosphorus released during mixed fill, plus some additional phosphorus, is taken up during the react phase. Settle During this phase, activated sludge is allowed to settle under quiescent conditions—no flow enters the basin and no aeration and mixing takes place. The activated sludge tends to settle as a flocculent mass, forming a distinctive interface with the clear supernatant. The sludge mass is called the sludge blanket. This phase is a critical part of the cycle, because if the solids do not settle rapidly, some sludge can be drawn off during the subsequent decant phase and thereby degrade effluent quality. Decant During this phase, a decanter is used to remove the clear supernatant effluent. Once the settle phase is complete, a signal is sent to the decanter to initiate the opening of an effluentdischarge valve. There are floating and fixed-arm decanters. Floating decanters maintain the inlet orifice slightly below the water surface to minimize the removal of solids in the effluent removed during the decant phase. Floating decanters offer the operator flexibility to vary fill 54| P a g e
DESIGN OF SAVINA STENA SANITARY LANDFILL
and draw volumes. Fixed-arm decanters are less expensive and can be designed to allow the operator to lower or raise the level of the decanter. It is optimal that the decanted volume is the same as the volume that enters the basin during the fill phase. It is also important that no surface foam or scum is decanted. The vertical distance from the decanter to the bottom of the tank should be maximized to avoid disturbing the settled biomass. Idle This step occurs between the decant and the fill phases. The time varies, based on the influent flow rate and the operating strategy. During this phase, a small amount of activated sludge at the bottom of the SBR basin is pumped out—a process called wasting. 4.6.2.3
Major Calculations
The following major calculations are necessary for the design of an SBR system The F/M Ratio The F/M ratio would simply be the digester loading divided by the concentration of volatile suspended solid (biomass) in the digester (kg-COD/kg-VSS.day). For any given loading, efficiency can be improved by lowering the F/M ratio and increasing the concentration of biomass in the digester. Also for given biomass concentration within the digester, the efficiency can be improved by decreasing the loading. The F/M can be calculated as follows: F/M = Organic Loading rate / Volatile Solid where,
Organic loading rate= COD of the influent stream (kg-COD/L.day)
Volatile solid= Volatile suspended solid concentration in the reactor (kg-VSS/L) F/M= kg-COD/kg-VSS.day
The hydraulic retention time (HRT) The hydraulic retention time calculation before proceeding experiments is also an important process control parameters. It shows the total time required by the liquid to degrade. The HRT plays an important role while anaerobic digestion of which the liquid has to stay within the digester until degradation. The HRT can be calculated as follows: HRT = CODin / OLR Where
HRT= Hydraulic retention time (days) OLR= Organic loading rate (kg-COD/L.day) CODin= Influent COD (kg-COD/L)
The flow rate 55| P a g e
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The HRT and flow rate examine the exact influent stream from feed inlet to the outlet. Normally, flow rate is controlled by means of a peristaltic pump with corresponding tube hosing of different diameter. The flow rate is designed according to the working volume of the reactor. The flow rate can be calculated as follows: Q = Vw/HRT Where,
Q= Flow rate of influence stream (L/day) Vw= Working volume of the reactor (L) HRT= Hydraulic retention time (days)
The organic loading rate Organic loading rate is presented as the weight of organic matter per day applied over a surface area, such as kg of BOD5 per day per square meter. The BOD5 is a measure of the oxygen needed to degrade organic matter dissolved in the wastewater over 5 days. It is reported as mg/l of oxygen consumed to degrade the wastewater in 5 days. BOD5 is one way to measure the amount of easily degradable organic matter in sewage. Organic loading rate is calculated as follows: OLR = BOD x Design flow / Area 4.6.2.4
SBR Unit
Pre-treatment To calibrate the C:N:P ratio since we have high N concentration, it is necessary to introduce C to the system (methanol) and P (H3PO4). Pump station feeding SBR unit Through a pumping station, equalized and homogenized leachate shall be pumped from the equalization tank to the entrance well of SBR 1. Inside the well, the appropriate quantity of nutrients is added, to facilitate the biological process. From the entrance well, the enriched leachate shall overflow towards the biological reaction tank SBR 1. Pumps shall be capable to feed the daily leachate flow to the SBR 1 within 1h. Two pumps shall be installed (one as spare), capacity of each pump shall be 65 m3/h. 4.6.2.5
The reactors
Description Provided the dosing of nutrients at the upstream well, leachate is introduced (manual weir) into the first sequential batch reactor where under aeration and stirring, biodegradation
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(nitrification/ denitrification) of organic load takes place. Sedimentation of suspended solids will also take place inside the SBR unit. Consecutively with SBR 1, the second biological reactor shall be located. Treated leachate from SBR 1 shall overflow to SBR 2 undertaking further treatment. Treated leachate from SBR 2 shall be collected at a well, upstream to the disinfection facility. Biological sludge from SBR 1 and 2 shall be collected at a second well prior its introduction to the sludge thickener. To achieve effluent requirements, SBR is aiming on the reduction of the pollutant load (BOD5, COD, SS, ΤΚΝ). Both tanks shall be rectangular, made of reinforced concrete and equipped with surface aerators (for the nitrification process) and agitators (for the denitrification process). Both tanks (SBR 1 and 2) shall be designed for a residence time of 18 days, for a volumetric loading of 0,16 – 0,40 kg BOD5/m3/d and for a solid loading of 0,05 – 0,15 kg BOD5/ kg MLVSS/d. Based on the design calculations SBR 1 shall have an effective volume of about 1.500 m3 while SBR 2 approximately 300 m3. More detailed sizing is provided in a later paragraph. Figure 4-3 presents an indicative arrangement
SBR 2 SBR 1 Effluent tank
sludge pump station Figure 4-3:SBR unit
SBR1 tank shall be served by two surface aerators, installed on a concrete bridge, of capacity 50 kg O2 / h. Sludge shall be collected through the bottom to the excess sludge pump sludge station. SBR1 shall communicate with SBR2 through a submerged opening. SBR2 tank shall be served by one surface aerator, installed on a concrete bridge, of capacity 15 kg O2 / h. SBR2 shall be of effective dimensions 4x4x3,5m. One agitator shall be installed at each tank for the denitrification phase.
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The total area required for the SBR tanks shall be approximately 620m2. 4.6.2.6
The process
The steps of operation are presented below. Step 1: Filling Filling period allows leachate to enter the SBR tank and rise its level from 75% to 100% of its capacity. Basic characteristics of the filling phase are: Volume of operation: 75% to 100% Additional characteristics:
on / off air supply
Undergoing processes: Food supply Incoming leachate is treated under specific processes and at the end of a full cycle of operation 90% of its flow is supplied as treated effluent, while the rest 10% is the collected waste sludge. Step 2: Aeration phase During this step the introduction of oxygen into the mixed liquid is performed. The aeration process refers to the biological degradation of the organic load and the nitrification of the NH4+. Basic characteristics of this phase are: Volume of operation: 100% Additional characteristics:
Air supply
Undergoing processes: substrate growth Step 3: Settlement During settlement period the separation of solids through their sedimentation from the supernatant cleaned effluent takes place. Settlement under SBR process is considered to be more effective in comparison to continuous flow systems, since this period no interference or turbulence is effected and are under complete still condition. Settlement period is approximately 1-2 h. Basic characteristics of this phase are: Volume of operation: 100% Additional characteristics:
no air supply
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Undergoing processes: settlement This period has a variable time schedule since it depends on how easily or not the sludge settles. If this period exceeds 3 hours then anaerobic organisms start to grow resulting to the production of N2, and reversing the settling process (N2 bubbles carry solids towards the surface and the escape of solids to the effluent). Step 4: Decant – Sludge removal The purpose of this step is the removal of clean effluent (supernatant liquid) from the batch reactor as well as the removal of waste sludge for controlling sludge retention time and concentration within the reactor. The removal of the clean effluent is performed under mild flow conditions in order to avoid sludge turbulence and minimizing solids concentration within the effluent. Several mechanisms of mild removal of the supernatant liquid has been developed and applied, like grated weirs, adjustable overflows etc. The most popular method is the adjustable overflows. The step-by-step detention of the overflows achieves low velocities and complete stillness within the tank. Typical decant time is about 45 minutes to 1 hour. Basic characteristics of this phase are: Volume of operation: 100% to 85% Additional characteristics:
no air supply
Undergoing processes: removal of clean effluent Step 5: Idle An idle period is used in a multi-tank system to provide time for one reactor to complete its fill phase before switching to another unit. Basic characteristics of this phase are: Volume of operation: 85% to 75% Additional characteristics:
no air supply
Undergoing processes: removal of excess sludge 4.6.2.7
Dimensioning
SBR 1 – Dimensions (effective) Length
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Width
14 m
Effective height
3,5 m
Surface
392 m2
Volume
1.370 m3
SBR 1 – Operation schedule Filling – Discharge
1,0 h
Nitrification
14,0 h
Denitrification
5,5 h
Sedimentation
2,0 h
Sludge removal
1,5 h
Total
24,0 h
SBR 2 – Dimensions (effective) Length
7,0 m
Width
7,0 m
Effective height
3,5 m
Surface
49,0 m2
Volume
171 m3
SBR 2 – Operation schedule Filling – Discharge
1,0 h
Nitrification
4,5 h
Denitrification
15,0 h
Sedimentation
2,0 h
Sludge removal
1,5 h
Total
24,0 h
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4.6.2.8
Effluent collection tank
Effluent from the SBR2 tank overflows to the effluent collection tank. Through there the treated effluent shall be send for recirculation. The tank is dimensioned to be sufficient to collect effluent for at least 3 days.
4.6.2.9
Sludge tank (thickener)
Next to the influent equalization tank the sludge thickener is situated. Biological sludge from SBR 1 and SBR 2 shall be collected to this tank and been subject of mechanical thickening with minimum retention time of 1-2 d, meaning a minimum effective volume of 30-60 m3. Daily sludge production is expected to be around 25,0 m3/d with 12,5 kg SS /m3. A sludge thickening tank shall be required, of capacity approximately 40 m 3. The area required is 30m2. Figure 4-4 shows the sludge thickener.
Figure 4-4 : Sludge Thickener layout
Thickened sludge produced: 9 m3/d, approximately 3% solids. Liquor return to equalization tank: 16,0 m3/d. Thickener – Dimensions (effective) Length
4,0 m
Width
4,0 m
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Inclined height 1,0 m Surface
16,0 m2
Volume
40,0 m3
Disposal of final effluent The treated leachates will be collected in the effluent collection tank. From the effluent collection tank a part of the treated leachates will be recirculated to the landfill body and the rest will be discharged to an applicable receiver according to the quality of the effluent
4.6.3 Recirculation 4.6.3.1
Introduction
A common practice for treated leachate is to be recirculated within the waste body. This practice incorporates significant advantages: Acceleration of waste biodegradation and increased production of biogas; Equalization of fluctuations in the chemical and biological concentrations of the leachate; Simultaneous recirculation of nutrients and microorganisms; Increase of humidity in the waste body. Apart from an easy-to-do and of lower cost methodology for leachate management, recirculation has been proved to enhance biological decomposition. 4.6.3.2
Process – Operational Principles About Recirculation
Leachate recirculation was traditionally considered as a methodology to increase leachate evapotranspiration and thus reduce the generated leachate volume. It is crucial to mention that recirculation results in a steadily increasing reservoir of leachate, if percolation of water into the landfill is greater than evaporation of collected leachate. Thus, in locations with low or insufficient rates of evaporation, the building up of leachate as a consequence of recirculation will be the norm and will require the eventual removal and treatment of excess leachate. Leachate recirculation may evoke increased landfill gas production, due to the raise of moisture level within the landfill body. Leachate recirculation could also be considered as a method to equalize leachate flow, using the landfill body as a leachate storage facility. 62| P a g e
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When applying leachate recirculation as a leachate treatment method, it is usually the degradable organic pollutants of the leachate that are targeted. Methanogenic waste can have a good treatment effect on easily degradable organic materials. A major pollutant in municipal solid waste (MSW) leachate is nitrogen, so another use of recirculation is denitrification. Acidogenic and methanogenic MSW have a good denitrifying effect. 4.6.3.3
Limitations In Use
In order to make recirculation work, it is necessary to remove substances from leachate that could cause clogging. Leachate should also be free from excessive concentrations of iron (Fe) and manganese (Mn), which may rapidly form poorly permeable incrustations on the landfill cover. Another necessity for a successful recirculation lies in the use of permeable daily cover materials. Materials finer than sand should be avoided. Adopting recirculation as a strategy to manage leachate should be handled really carefully. Firstly, intentional introduction of moisture into the landfill may lead to pollution of the surroundings by leachate migration, either from the bottom or the sides of the landfill. In addition, continuous recirculation will lead to the build-up of significant concentrations of salts, metals and other undesirable compounds in the leachate. Furthermore, in case of intermediate coverage of the landfill area, the recirculation of leachate may lead to the formation of perched or ponded (accumulated) water within the landfill, which may also eventually leak through the sides of the landfill. The following table summarizes the main advantages and disadvantages of the method. Table 4-17: Advantages and disadvantages of recirculation
Advantages Low cost Simple installation Leachate volume losses due to evaporation Raises biogas production rate if it has dropped due to humidity absence in landfill body
Disadvantages Not enough in humid areas to solve the problem of leachate production Steadily increasing reservoir of leachate if Rainfall > Evaporation Leachate migration through the sides of landfill may happen Continuous recirculation leads to build-up of salts, metals and other undesirable compounds in leachate
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4.7
BIOGAS MANAGEMENT
4.7.1 Introduction A sanitary landfill can be defined as the biochemical reactor of the anaerobic fermentation of organic and other biodegradable fractions included within disposed municipal solid waste (MSW). Landfill control systems are employed to prevent unwanted movement of landfill gas into the atmosphere or the surrounding soil. Recovered landfill gas can be used to produce energy or to be flared under controlled conditions to eliminate the discharge of greenhouse gases to the atmosphere. Landfill gas is composed of a number of gases, but mainly methane (CH4) and carbon dioxide (CO2) at a ratio of 50:50. The rest gases represent no more than 3-5% of the total landfill gas volume. The principal gases are produced from the decomposition of the organic fraction of MSW. Landfill gases occur in five or less sequential phases: i. Aerobic phase: in the 1st phase organic biodegradable components undergo microbial decomposition as they are placed in the landfill and soon after under aerobic conditions until entrapped O2 is consumed. This may last for a few weeks up to several months. The predominant gases synthesized during this stage are carbon dioxide (CO2) and water vapour (H2O). ii. Transition phase: The second phase begins as conditions shift from aerobic to anaerobic as a result of oxygen depletion. The principal gases produced are CO2 – and – to a lesser extent – hydrogen (H2) iii. Acid phase: The microbial activity initiated during phase II accelerates with the production of significant amounts of organic acids and lesser amounts of hydrogen gas. This three steps phase includes:
iv.
v.
The hydrolysis of higher-molecular mass compounds into compounds suitable for use by microorganisms as source of energy and cell carbon.
The microbial conversion of the compounds resulting from step a, into lower molecular mass intermediate compounds (CH3COOH).
The last step involves the conversion of the intermediate compounds produced in phase b into carbon dioxide and lesser amounts of hydrogen gas.
Methane fermentation phase: another group of microorganisms convert the acetic acid and hydrogen gas into CH4 and CO2. Microorganisms responsible for this conversion are strictly anaerobic and are called methanogenic. Maturation phase: the maturation phase occurs after the readily available biodegradable organic material has been converted to CH4 and CO2 in phase IV. The rate of landfill gas generation diminishes significantly since most of the available nutrients have been removed with leachate.
During the anaerobic phases, production of sulfur and carbon compounds in trace concentrations (sulfides and volatile organic acids) is observed. 64| P a g e
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4.7.2 Estimation of landfillgasproduction In literature, several approaches have been published with regards to the chemical equation (kinetics) that best represents landfill gas formation within a landfill. The most widely used is the 1st order equation, which is adopted by US EPA and many researchers, especially when field data are limited (i.e. recording of methane production of an existing landfill in order to determine the equation parameters). The US EPA has produced a mathematical model that is called LANDGEM, which provides a relatively simple, but yet strong approach to predict landfill gas emissions. LANDGEM is based on a first-order decomposition equation for quantifying emissions from the biodegradation of landfilled waste in municipal solid waste (MSW) landfills: n
QCH 4
1
M
k Lo 10i e
i 1 j 0.1
k tij
Whereas:
QCH4
i
= 1-year time increment
n
= (year of the calculation) - (initial year of waste acceptance)
j
= 0.1-year time increment
k
= methane generation rate (year-1)
= annual methane generation in the year of the calculation (m3/year)
k=– ln(0,5)/t1/2
t 1/2 = “half life” time, thus the time necessary to reduce the initial concentration of the organic matter by 50%
Lo
= potential methane generation capacity (m3/Mg)
Mi
= mass of waste accepted in the ith year (Mg)
tij = age of the jth section of waste mass Mi accepted in the ith year (decimal years, e.g., 3,2 years)
In order to estimate parameters Lo and k, literature is used since there is no field data to create specific values for the landfill in study. In particular, Lo is estimated by using the methodology suggested by Andreottola G., Cossu R., 1988, in “Modellomatematico di produzione del biogas in unoscaricocontrollato, RS - Rifiuti solidi, 2(6), 473 – 483” and by adopting the waste composition as presented in Figure 3-1: Composition of the household waste in Prishtina, March 2011. According to this methodology, Lo is estimated equal to 74.41 m3 CH4/ton of waste input. 65| P a g e
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Lastly, the parameter k, is estimated with the use of the following table Table 4-18: k values used in the estimations 1 Methane generation rate constant (k) (years-1) Foodwaste Garden Paper Wood and straw Textiles
Range
Default
0.1–0.2 0.06–0.1 0.05–0.07 0.02–0.04 0.05–0.07
0.185 0.1 0.06 0.03 0.06
Based on this table and on the composition of waste, the k value is estimated equal to 0.081 y-1. As presented below, the maximum biogas quantity from cell A is observed in year 2025and reaches 149,34 m3/h.Considering 30% landfill gas losses and having a safety factor (S.F) of 1.5, the maximum recoverable amount of landfill gas shall be app. 157 m3/hr. This value will be used as the nominal capacity of the flare unit and as the design parameter for the dimensioning of the pipingnetwork. Table 4-19: Production and recovery of biogas from cell A in m3/h Year
ProductionRate
RecoveryRate
Design capacity (Recovery Rate multiplied by S.F=1.5)
(m3/year)
(m3/hr)
(m3/hr)
(m3/hr)
2015
0,00
0,00
0,00
0,00
2016
156.872,95
17,91
12,54
18,80
2017
306.244,01
34,96
24,47
36,71
2018
448.840,11
51,24
35,87
53,80
2019
585.331,66
66,82
46,77
70,16
2020
716.348,84
81,77
57,24
85,86
2021
842.472,79
96,17
67,32
100,98
2022
964.239,43
110,07
77,05
115,58
2023
1.082.154,93
123,53
86,47
129,71
2024
1.196.674,13
136,61
95,62
143,44
2025
1.308.252,30
149,34
104,54
156,81
2026
1.206.462,02
137,72
96,41
144,61
2027
1.112.591,66
127,01
88,91
133,36
2028
1.026.025,01
117,13
81,99
122,98
2029
946.193,79
108,01
75,61
113,41
2030
872.573,95
99,61
69,73
104,59
2031
804.682,19
91,86
64,30
96,45
1
Values for k constant can be found at theIPCC Waste Model Spreadsheet, included in the IPCC Guidelines for National Greenhouse Gas Inventories 2006.
These k values are for Eastern European countries with wet temperate. The “wet temperate” choice is based on Figure 3A.5.1 as included in Volume 4: Agriculture, Forestry and Other Land Use, Chapter 3 of the IPCC Guidelines, where the area of Kosovo is presented as an area with cold and moist climate
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Year
ProductionRate
RecoveryRate
Design capacity (Recovery Rate multiplied by S.F=1.5)
(m3/year)
(m3/hr)
(m3/hr)
(m3/hr)
2032
742.072,84
84,71
59,30
88,95
2033
684.334,89
78,12
54,68
82,03
2034
631.089,32
72,04
50,43
75,64
2035
581.986,59
66,44
46,51
69,76
2036
536.704,36
61,27
42,89
64,33
2037
494.945,38
56,50
39,55
59,33
2038
456.435,50
52,10
36,47
54,71
2039
420.921,94
48,05
33,64
50,45
2040
388.171,56
44,31
31,02
46,53
2041
357.969,36
40,86
28,60
42,91
2042
330.117,09
37,68
26,38
39,57
2043
304.431,90
34,75
24,33
36,49
2044
280.745,17
32,05
22,43
33,65
2045
258.901,43
29,55
20,69
31,03
2046
238.757,26
27,26
19,08
28,62
2047
220.180,44
25,13
17,59
26,39
2048
203.049,02
23,18
16,23
24,34
2049
187.250,52
21,38
14,96
22,44
2050
172.681,25
19,71
13,80
20,70
2051
159.245,56
18,18
12,73
19,09
2052
146.855,25
16,76
11,74
17,60
2053
135.428,98
15,46
10,82
16,23
2054
124.891,76
14,26
9,98
14,97
2055
115.174,39
13,15
9,20
13,81
2056
106.213,09
12,12
8,49
12,73
2057
97.949,05
11,18
7,83
11,74
2058
90.327,99
10,31
7,22
10,83
2059
83.299,90
9,51
6,66
9,98
2060
76.818,65
8,77
6,14
9,21
2061
70.841,67
8,09
5,66
8,49
2062
65.329,74
7,46
5,22
7,83
2063
60.246,68
6,88
4,81
7,22
2064
55.559,10
6,34
4,44
6,66
The landfill gas management system shall consist out of the following:
Vertical collection wells (boreholes) 67| P a g e
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Horizontal piping network Biogas Collection Stations Condensate traps system Blower and flare unit
4.7.3 Biogas management system – Technical specifications The landfill gas management system shall consist out of the following: Collection wells (boreholes) For the collection of biogas vertical collection wells (boreholes) will be constructed at the end of the operation time of the Cell A, when waste has reached final height. The boreholes will have a diameter of 1000mm and will be filled with a material with permeability of at least 1x10-3 m/s and d = 16-32 mm (gravel or crashed stone). In this filter, the drainage pipe (screen pipe) with an internal diameter of 300 mm will be immersed. The screen pipe will lie on a bed of gravel or crashed stone placed at the bottom of the borehole, with a thickness no less than 30cm. This ensures a uniform extraction of the gas generated inside the deposit’s body, with a supra pressure of about 40 hPa. To cover enough volume of the deposit body and to be able to drive the collected gas toward the desired direction, it is necessary to generate an effective sub pressure of 30 hPa at the top of the gas well. These wells (boreholes) should have a depth that will reach 2m above the bottom drainage layer.For the construction of the wells a drilling machine will be utilised. It is proposed that screen pipes are made of HDPE, which is an erosion resistant material, with a pressure resistance no less than 6 atm.The walls of the screen pipes will be perforated and the diameter of the holes (according to the granulation of the gravel or crashed stone filters) will be smaller than 0.5 xd, which means 8-12 mm. Pipes with circular perforations are preferred because of their higher strain and shear resistances, and their higher stability against the loads resulted in compaction of the waste body procedure. The upper part of the pipe shall be sealed, meaning that the pipe will have no holes for at least 1m before reaching the top layer of the landfill. At their final height, all pipes from the vertical wells shall end up to a well head. The well- head shall be made of HDPE and shall be equipped with a press relief valve as well as flow, temperature and sampling access points. The well –head will be connected to the horizontal transfer pipe with the use of a side branch, (special fitting), made of flexible HDPE. At the branch of the well - head a butterfly valve shall be positioned assisting the landfill gas control from the specific well. In order to protect the well head a prefabricated concrete pipe (approximately 1m high and 2m diameter) shall be positioned on top of each well with a metal cap for protection and easy access.
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A total of 13 wells shall be constructed for the biogas collection of cell A. The distance between two biogas wells shall be 50 m the most, considering an effective radius of approx. 30 m around each well. The relative positioning of the wells is represented in the following figure.
Figure 4-5: Landfill gas well positioning
Biogas transfer piping network Each gas collection well will be connected to the gas collection station(s) through a gas collection pipe. Gas collection pipes shall be installed with a slope of at least 5% accountable to the gas collection station, to evacuate the water condensed inside the pipe. These pipes shall be provided with flexible devices that allow the connection to the gas collection stations in a way that damage from tamping, pressure forces, transversal forces and torsion forces is minimized. The pipes and the flexible connections shall be of HDPE with a pressure resistance ≥ PN 6. The collection pipe diameter will be ≥ 300 mm. The gas collection pipes will bear butterfly valves at their connection to the collection station, assisting the landfill gas control from the specific pipe and allowing to stop the gas flow. The pipes shall be placed in a trenchto protect them against damage and freezing at the surface with a layer of soil or waste of at least 30 cm thick. Biogas collection stations Within the gas collection stations, the individual collection pipes are connected to the main discharge pipe. The number of the gas collection stations is determined accounting the landfill dimensions, number of gas collection wells and their distribution within the deposit. Based on the proposed design one (1) collection station is necessary for cell A. Within the gas collection station, each collecting pipe is fitted with a specific portion provided with a sampling device. This device is made of a pipe fragment with a diameter of 50mm to ensure a constant gas flow > 2 m/s; optimum gas flow is about 6-8 m/s. The pipe length has to be 10 x ND ahead the measuring nozzle and respectively 5 x ND beyond. Between the measuring area and the collecting cylinder (where the collection pipes end), a butterfly valve for closing and adjusting
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is placed. A butterfly valve is placed between the collection cylinder and the main discharge pipe, as well. The infrastructures containing the gas collection stations shall be completely sealed and provided with ventilation systems (at least two ventilation grated windows of 50 x 50 cm) and non-authorized personnel access will be strictly forbidden. Warning signs on the potential risks related to biogas presence shall be located within the gas collection stations area, no smoking and no fire signs included. The stations shall be placed outside the sealed base area and deposit surface respectively, and should be accessible directly from the perimetric road. Biogas discharge main pipe (perimetric biogas pipe) The biogas collection stations are connected through a main pipe (perimetric biogas pipe) that leads biogas to the blower. Biogas discharge main pipe shall allow access and adjustment from the water collection tanks containing the condensate separators, if damaged. Its slope shall be at least 0.5%, in order to evacuate particles contained within condensate. The nominal diameter of the pipe has to be at least 400 mm. Such pipes will be installed in a trench in a depth not less than 30 cm and will be located outside the sealing surface area, and by no means below the storm water collection equipments (ditches) and below the access roads. Condensate traps system Since the maximum biogas collected quantity is approx.. 150 m3/h and 100ml of condensate are produced per cubic meter of biogas thus, the maximum quantity of condensate is expected to be 15lt/h or approximately 0,15 m3/d. Condense is discharged into through a siphon type device back to the waste body. Such devices are placed at the lower points of the pipe collection network, connecting the wells with the collection station. The collection station is equipped with a reservoir from which condense is transferred to the leachate treatment plant. Flare unit In order to actively pump the landfill gas out of the deposit a flare shall be installed. Based on the biogas production calculation presented above, the flare unit shall have a total capacity of more than 150 m3/h. The landfill gas flare will be of compact design and will mainly consist of the blower unit and the controlled combustion unit.
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The flare will be closed-type flare, allowing high efficiency with combustion taking place at temperatures above 850°C, ensuring compliance with the emission regulations. The combustion plant shall be installed on a concrete base. The flare unit shall be equipped with:
Blower unit with EEx-proof motor
Ignition burner
Combustion chamber
Pressure, temperature control and monitoring
Electrical control weather proof cabinet
Portable CH4, O2, CO2 analyzer
Ability to operate at 1/5 of nominal capacity.
The compact plant shall also be equipped with all necessary safety features for the safe handling and combustion of the landfill gas (guideline EN60079-ff for explosion protection). The flare unit will be installed at the end of the operation of cell A.
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4.8
FLOOD PROTECTION
The main aims of the construction of flood protection works are the following: To avoid the inflow of storm water in the landfill and in this way reduce the leachate production To avoid the inflow of storm water in the site and in this way protect its structural stability To protect the buildings and the roads of the site from storm water erosion. This text is accompanied by the overall design of the general layout of the flood protection works. The flood protection works of the site consist of the following: Circumferential ditches (ditches A and B) which are lined with armed concrete (15-20 cm thick). These ditches are perpendicular and stretch around the landfill to prevent storm water from entering in it, as well as, to collect the stormwater from the surface of the final cap. A concrete well will be situated among these ditches (ditches A and B) and a circular concrete pipe (D1200mm diameter) will originate. This pipe will lead to a secondconcrete well and to another concrete pipe (D1200mm diameter), which, finally, discharge the watertowards the final receptor. Circumferential earthen ditches (ditches C, D, E, F and G). These ditches are trapezoid and stretch around the perimeter of the area where the facilities of the sanitary landfill are situated in order to protect them from the stormwater. Triangular gutters, which collect the runoff from the parts outside the landfill (mostly roads) before they reach the slopes of the embankments or the buldings.This flood protection system of the existing road network outside the perimeter of the landfill lead the storm water safely to nearby natural receptors. Circular culverts, of diameter D400 and D500, for the crossing of road. Concrete wells where there is confluence of ditches or there is a connection between a ditch and a pipe. All the wells are covered with grate for the prevention of accident occurrence and debris entering the culverts. In some places where the circular pipes and the ditches discharge the water towards the final receptor, the natural soil will be covered with stepped slope gutter and with riprap (consisting of gravel with weight 5-20kg) in order to protect the soil near the embankments from erosion, as well as lead the storm water safely away from them. 73| P a g e
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For the protection of the embankments from erosion, the foot of each embankment will be lined with shotcrete in the places where stormwater may gather. The lining will be implemented as it is shown in the relevant detail plan (0.50m along the surface). Finally, the flood protection works should be completed by a perpendicular culvert which passes underneath the road Raska -Mitrovica about 250m away of the landfill site. It should be noted here that crucial element of the flood protection system is the slope free surfaces of the ground inside the site: all the surfaces must be sloped towards the nearest culvert in order to prevent the retention of water in hollows of the ground. The slope of the free surfaces must be at least 0.5% with the directions shown in the general layouts of flood protection works.
4.8.1 Hydrology Runoff estimation method The hydrological calculations were made for a return period of 50 years. A safety factor was also adopted for the maximum discharge that the ditches can convey. The calculation of the runoff was made using the rational method: Q= 0.278 x c x i x Α (lt/sec) where: c: runoff coefficient i: rainfall intensity in the time of concentration (mm/hr) Α: area of catchment basin (1000m2) The hydrologic calculations are presented in the calculations appendix. IDF curve (ombrian curve) – Critical rainfall intensity The rainfall data derived from the daily maximum samples constituted from observed data in the Drini River, in Kosovo2. For durations shorter than 24 hours, some statistic data exist in Master Plan. For a given duration t (in this study, t=10min), the rainfall can be estimated from the 24-hour rainfall by the following relationship:
2 Technical Report on the Hydrology o fthe Drini River Basin. GFA, International Office for Water, BRL. Institutional support to the Ministry of Environment and Spatial Planning (MESP) and River Basin Authorities. An EU funded project managed by the European Commission Liaison Office (ECLO).
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t Pt P24 24
0.21
where: P24: maximum 24-hour annual rainfalls (mm), for return period T=50 years t: duration (h) In this study, t=10min, and P24=88mmfor Prishtina Concentration time The rainfall duration used for the calculation of critical intensity corresponds to the concentration time of the catchment basin. For the calculation of the concentration time the Giandotti equation is used:
(Giandotti)
tc
4 A 1,5 L 0,8 Δz
where: tc = time of concentration (min) A = area of basin (km2) L = longest watercourse length (km) Δz = Hm – H0, where Hm the mean altitude of the basin and H0 the altitude in the exit of the basin. In this case, we accept the concentration time equal to 10 minutes, because of the small size of the basins. Runoff coefficient For the runoff estimation of the final cover of the landfill a runoff coefficient of 0.90 was used. For the runoff estimation of external basin, the runoff coefficient is equal to 0.50. For the runoff estimation of the roads, the runoff coefficient is equal to 0.90 All the coefficients are based on the international literature on the particular subject.
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Ditch and culvert design – Hydraulic calculations For the dimensioning of the ditches and the culverts the Manning formula was used assuming that the continuity assumption is valid: Q = A x V (m3/s) V = (1/n) x R2/3 x S1/2 where: Q = discharge (m3/s) A = “wet” area (m2) V = velocity (m/s) (n) = manning coefficient R = hydraulic radius (m) S = slope More specifically the calculations were made with the use of FLOWMASTER software of HAESTAD METHODS, for pipes and open channels. The mathematical model of this program is based on the continuity equation and on Manning formula. The dimensioning of the ditches was made in order the height y of the flow during the design storm divided by the total height of the ditch h to be below 0.70, i.e. y/h < 0.70 for a design storm of 50years return period. The velocity in the ditches and the pipes is everywhere below 6 m/s. The Manning coefficient is n=0.016 for concrete surfacesand n=0.025 for earthen surfaces. The hydraulic calculations and the dimensions of the ditches and the culverts are shown in the hydraulic calculations appendix.
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ΗΥDROLOGIC CALCULATIONS OF DITCHES, GUTTERS, CULVERTS
Crosssection of ditch
Length (m)
A1
Distance from start (m)
Elevati on (m)
0,00
580,85
Area of external basin (1000m2)
Total area of external basin (1000m2)
Area of landfill basin (1000 m2)
Total area of landfill basin (1000m2)
Area of roads (1000m2)
Total area of roads (1000 m2 )
Runoff coeffici ent c1 (extern al basin)
Runoff coefficie nt c2 (internal basin)
Runoff coefficient c3 (roads)
Conc entra tion time t (h)
Return period Τ (yr)
Rainfall max 24h (mm)
Critical rainfall i (mm/h)
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
A2
55,08
55,08
585,10
0,000
107,197
1,338
14,946
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,577
0,866
A3
102,88
157,96
598,50
0,000
107,197
5,044
13,608
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,567
0,850
A4
89,55
247,51
605,60
0,000
107,197
4,896
8,564
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,528
0,792
A5
97,40
344,91
607,80
107,197
107,197
3,668
3,668
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,490
0,735
0,00
580,85
0,000
0,000
B1 B2
41,90
41,90
585,90
0,000
163,952
0,999
14,150
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,815
1,223
B3
101,73
143,64
598,50
45,607
163,952
4,915
13,151
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,808
1,211
B4
100,62
244,26
606,00
35,493
118,345
4,960
8,236
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,573
0,860
B5
86,72
330,98
607,80
82,852
82,852
3,276
3,276
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
0,382
0,573
0,000
0,000
0,000
0,000
0,181
0,181
0,50
0,90
0,90
0,17
50
88,00
30,99
0,001
0,002
1,310
1,310
0,000
0,000
0,679
0,679
0,50
0,90
0,90
0,17
50
88,00
30,99
0,011
0,016
4,518
4,518
0,000
0,000
2,258
2,258
0,50
0,90
0,90
0,17
50
88,00
30,99
0,037
0,055
0,000
0,000
0,000
0,000
0,446
0,446
0,50
0,90
0,90
0,17
50
88,00
30,99
0,003
0,005
590,80 R1
60,82
60,82
595,20 585,00
R2
130,07
130,07
594,80 580,80
R3
109,41
109,41
584,09 577,50
R4
34,10
34,10
579,75 568,90
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Crosssection of ditch
R5
Length (m)
Distance from start (m)
190,52
190,52
Elevati on (m)
Area of external basin (1000m2)
Total area of external basin (1000m2)
Area of landfill basin (1000 m2)
Total area of landfill basin (1000m2)
Area of roads (1000m2)
Total area of roads (1000 m2 )
Runoff coeffici ent c1 (extern al basin)
Runoff coefficie nt c2 (internal basin)
Runoff coefficient c3 (roads)
Conc entra tion time t (h)
Return period Τ (yr)
Rainfall max 24h (mm)
Critical rainfall i (mm/h)
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
580,80
18,769
18,769
0,000
0,000
0,353
0,353
0,50
0,90
0,90
0,17
50
88,00
30,99
0,084
0,125
0,000
0,000
0,000
0,000
0,705
0,705
0,50
0,90
0,90
0,17
50
88,00
30,99
0,005
0,008
27,876
27,876
0,000
0,000
1,993
1,993
0,50
0,90
0,90
0,17
50
88,00
30,99
0,135
0,203
1,219
1,219
0,000
0,000
0,220
0,220
0,50
0,90
0,90
0,17
50
88,00
30,99
0,007
0,010
0,000
0,000
0,000
0,000
0,399
0,399
0,50
0,90
0,90
0,17
50
88,00
30,99
0,003
0,005
0,000
0,000
0,000
0,000
0,799
0,799
0,50
0,90
0,90
0,17
50
88,00
30,99
0,006
0,009
0,000
0,000
0,000
0,000
0,543
0,543
0,50
0,90
0,90
0,17
50
88,00
30,99
0,004
0,006
9,107
9,107
0,000
0,000
0,899
0,899
0,50
0,90
0,90
0,17
50
88,00
30,99
0,046
0,069
3,527
3,527
0,000
0,000
0,220
0,220
0,50
0,90
0,90
0,17
50
88,00
30,99
0,017
0,025
1,310
1,310
0,000
0,000
1,078
1,078
0,50
0,90
0,90
0,17
50
88,00
30,99
0,014
0,021
271,149
271,149
29,096
29,096
0,000
0,000
0,50
0,90
0,90
0,17
50
88,00
30,99
1,393
2,089
275,667
275,667
29,096
29,096
2,258
2,258
0,50
0,90
0,90
0,17
50
88,00
30,99
1,429
2,144
568,88 R6
51,42
51,42
572,20 568,40
R7
9,50
9,50
568,88 562,00
R8
79,56
79,56
568,40 585,00
C
20,19
20,19
585,14 584,09
D
105,89
105,89
585,14 572,20
E
68,78
68,78
577,50 568,88
F
90,77
90,77
569,35 561,66
G
67,80
67,80
562,00 584,09
Pipe 1
12,37
12,37
585,00 580,80
Pipe 2
5,69
5,69
580,85 580,70
Pipe 3
4,85
4,85
580,80
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DESIGN OF SAVINA STENA SANITARY LANDFILL
Crosssection of ditch
Length (m)
Distance from start (m)
Elevati on (m)
Area of external basin (1000m2)
Total area of external basin (1000m2)
Area of landfill basin (1000 m2)
Total area of landfill basin (1000m2)
Area of roads (1000m2)
Total area of roads (1000 m2 )
Runoff coeffici ent c1 (extern al basin)
Runoff coefficie nt c2 (internal basin)
Runoff coefficient c3 (roads)
Conc entra tion time t (h)
Return period Τ (yr)
Rainfall max 24h (mm)
Critical rainfall i (mm/h)
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
27,876
27,876
0,000
0,000
1,252
1,252
0,50
0,90
0,90
0,17
50
88,00
30,99
0,130
0,195
27,876
27,876
0,000
0,000
1,993
1,993
0,50
0,90
0,90
0,17
50
88,00
30,99
0,135
0,203
568,88 Pipe 4
4,02
4,02
568,90 568,38
Pipe 5
5,01
5,01
568,40
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DESIGN OF SAVINA STENA SANITARY LANDFILL
HYDRAULIC CALCULATIONS OF DITCHES, GUTTERS, CULVERTS
Crosssection of ditch
Length (m)
A1
Distance from start (m)
Elevation (m)
0,00
580,85
Slope of ground
Design slope
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
Distance of ditches (m*m)
perpendicular b=0,50m h=0,60m perpendicular b=0,50m h=0,60m perpendicular b=0,50m h=0,60m perpendicular b=0,50m h=0,60m
A2
55,08
55,08
585,10
0,0772
0,0772
0,577
0,866
A3
102,88
157,96
598,50
0,1302
0,1302
0,567
0,850
A4
89,55
247,51
605,60
0,0793
0,0793
0,528
0,792
A5
97,40
344,91
607,80
0,0226
0,0226
0,490
0,735
perpendicular b=0,50m h=0,60m
B1
0,00
0,00
580,85
B2
41,90
41,90
585,90
0,1205
0,1205
0,815
1,223
B3
101,73
143,64
598,50
0,1239
0,1239
0,808
1,211
perpendicular b=0,50m h=0,50m perpendicular b=0,50m h=0,50m perpendicular b=0,50m h=0,50m
Flow depth y (m)
Velocity (m/sec)
y/h
Maximum capacity (m3/sec)
Safety factor (max capacity/1,5*Q)
0,26
4,41
0,433
1,639
1,89
0,21
5,33
0,350
2,129
2,50
0,24
4,36
0,400
1,661
2,10
0,37
2,64
0,617
0,887
1,21
0,000
0,59
5,67
1,180
1,643
1,34
0,28
5,72
0,560
1,666
1,38
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DESIGN OF SAVINA STENA SANITARY LANDFILL Crosssection of ditch
Length (m)
Distance from start (m)
Elevation (m)
Slope of ground
Design slope
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
B4
100,62
244,26
606,00
0,0745
0,0745
0,573
0,860
B5
86,72
330,98
607,80
0,0208
0,0208
0,382
0,573
0,00 R1
60,82
130,07
60,82
109,41
130,07
34,10
109,41
190,52 0,00
Maximum capacity (m3/sec)
Safety factor (max capacity/1,5*Q)
0,26
4,34
0,520
1,292
1,50
0,32
2,42
0,640
0,682
1,19
0,002
triangular Η:V=1:3, Η:V=1:1, h=0,30m
0,04
0,85
0,133
0,188
89,66
0,016
triangular Η:V=1:3, Η:V=1:1, h=0,30m
0,10
1,57
0,333
0,192
11,74
0,055
triangular Η:V=1:3, Η:V=1:1, h=0,40m
0,19
1,55
0,475
0,261
4,72
0,005
triangular Η:V=1:3, Η:V=1:1, h=0,30m
0,06
1,08
0,200
0,180
34,67
0,125
triangular Η:V=1:3, Η:V=1:1, h=0,50m
0,23
2,43
0,460
0,682
5,45
perpendicular b=0,50m h=0,50m perpendicular b=0,50m h=0,50m
595,20
0,0723
0,0723
0,001
594,80
0,0753
0,0753
0,011
584,09
0,0301
0,0301
0,037
577,50 34,10
0,00 R5
y/h
580,80
0,00 R4
Velocity (m/sec)
585,00
0,00 R3
Flow depth y (m)
590,80
0,00 R2
Distance of ditches (m*m)
579,75
0,0660
0,0660
0,003
568,90 190,52
580,80
0,0624
0,0624
0,084
568,88
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DESIGN OF SAVINA STENA SANITARY LANDFILL Crosssection of ditch R6
Length (m)
51,42
Distance from start (m)
51,42
0,00 R7
9,50
79,56
9,50
20,19
79,56
105,89
20,19
68,78 0,00
1,5 Χ discharge 50years Q (m3/sec)
Distance of ditches (m*m)
Flow depth y (m)
Velocity (m/sec)
y/h
Maximum capacity (m3/sec)
Safety factor (max capacity/1,5*Q)
0,08
1,22
0,267
0,178
21,71
0,0646
0,0646
0,005
0,008
triangular Η:V=1:3, Η:V=1:1, h=0,30m
568,88
0,0505
0,0505
0,135
0,203
triangular Η:V=1:3, Η:V=1:1, h=0,50m
0,28
2,53
0,560
0,614
3,02
0,010
triangular Η:V=1:3, Η:V=1:1, h=0,30m
568,40
0,09
1,44
0,300
0,198
19,03
0,005
trapezoid Η:V=1:1, h=0,30m, b=0,30m
0,03
0,30
0,100
0,175
37,73
0,009
trapezoid Η:V=1:1, h=0,30m, b=0,30m
0,04
0,42
0,133
0,209
22,55
0,006
trapezoid Η:V=1:1, h=0,30m, b=0,30m
0,02
0,71
0,067
0,581
92,09
0,0804
0,0804
0,007
585,14
0,0070
0,0070
0,003
584,09 105,89
0,00 E
Discharge Q (m3/sec)
585,00
0,00 D
Design slope
562,00
0,00 C
572,20
Slope of ground
568,40
0,00 R8
Elevation (m)
585,14
0,0100
0,0100
0,006
572,20 68,78
577,50
0,0771
0,0771
0,004
568,88
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DESIGN OF SAVINA STENA SANITARY LANDFILL Crosssection of ditch F
Length (m)
90,77
Distance from start (m)
90,77
0,00
Elevation (m)
569,35
Slope of ground
Design slope
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
Distance of ditches (m*m)
Flow depth y (m)
Velocity (m/sec)
y/h
Maximum capacity (m3/sec)
Safety factor (max capacity/1,5*Q)
0,16
0,62
0,320
0,219
3,16
5,84
0,0052
0,0052
0,046
0,069
trapezoid Η:V=1:1, h=0,30m, b=0,50m
561,66
G
67,80
67,80
562,00
0,0050
0,0050
0,017
0,025
trapezoid Η:V=1:1, h=0,30m, b=0,30m
0,09
0,46
0,300
0,148
Crosssection of ditch
Length (m)
Distance from start (m)
Elevation (m)
Slope of ground
Design slope
Discharge Q (m3/sec)
1,5 Χ discharge 50years Q (m3/sec)
Pipe diameter
Flow depth y (m)
Percent full
Velocity (m/sec)
Velocity 10% (m/sec)
0,0738
0,0738
0,014
0,021
D400
0,05
0,12
1,64
2,39
0,0093
0,0093
1,393
2,089
D1200
0,57
0,47
2,64
1,76
0,0200
0,0200
1,429
2,144
D1200
0,47
0,39
3,52
2,59
0,0050
0,0050
0,130
0,195
D500
0,28
0,56
1,15
0,72
0,0050
0,0050
0,135
0,203
D500
0,29
0,57
1,16
0,72
0,00 Pipe 1
12,37
584,09 12,37
0,00 Pipe 2
5,69
580,80 5,69
0,00 Pipe 3
4,85 4,02
4,85
5,01
580,80 568,88
4,02
0,00 Pipe 5
580,85 580,70
0,00 Pipe 4
585,00
568,90 568,38
5,01
568,40
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4.9
LANDFILL MONITORING
4.9.1 Introduction Environmental monitoring refers to periodic inspections and testing performed to assess the impacts of the landfill on its surrounding environment. The overall monitoring system of the landfill will consist of the following parts:
Leachate monitoring system
Groundwater monitoring system
Surface water monitoring system
Biogas monitoring system
Settlements monitoring system.
Part of the overall monitoring system is also a series of parameters, which have a significant role in organizing and monitoring the various processes and operations of the landfill. These parameters are the following:
Meteorological data
Volume and composition of the incoming waste
Volume and composition of the incoming soil material
Monitoring of all the supportive works and registering of all their problems that affect the proper operation of the total plant.
All the data collected from the monitoring systems should be kept on-site in appropriately organized records.
4.9.2 Leachate monitoring system Since the landfill is equipped with a leachate treatment plant, leachate sampling and testing is considered to be of vital importance. Slight changes in Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD) or heavy metals concentration, can affect the efficiency of the treatment system used. The operator of the treatment plant should also be able to have an estimation of the produced quantities of leachate, while he must be able to check the effectiveness of the leachate treatment plant. The parameters measured as well as the frequency of sampling are shown in the following table:
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Table 4-20: Parameters and Frequency for Leachate Monitoring
PARAMETERS Leachate volume Leachate composition Treated leachate composition
FREQUENCY Operational Aftercare Period period Monthly Every 6 months Every 3 Every 6 Months months Monthly Monthly
The volume of the produced leachate can be estimated from the operational hours of the pump installed in the landfill feeding the equalization tank. If you multiply the operational hours of the pump, which can be registered from the automation system of the plant, with its known capacity, then you can get a close estimation of the produced quantities of leachate. Leachate samples will be taken from the discharge pipe of the leachate pump and from the equalization tank of the leachate treatment plant, while treated leachate samples will be taken from the effluent tank of the leachate treatment plant. The parameters to be measured are:
•
pH
•
Conductivity
•
Odours
•
Temperature
•
BOD5
•
COD
•
TOC
•
SO-4
•
Ammonium (NH4-N)
•
Organic N
•
Cl
•
Zn
•
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•
Cd
•
Cu
•
Ni
•
Phenoles
•
Phosphate
•
Total Solids (TS)
•
Volatile Solids (VS)
•
Suspended solids (SS)
•
Disolved Solids (DS)
The sampling must be done according to the ISO 5667-11 while the chemical analysis should be according to the “Standard methods for the examination of water and wastewater” by AWWA, APHA, WEF, as shown in the following table: Table 4-21: Standard methods for the examination of water and wastewater
No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
PARAMETER pH Conductivity Odours B.O.D. C.O.D. T.O.C SO-4 Ammonium (NH4-N) Organic N Cl Zn As Cd Cu Ni Phenols Phosphate Total Solids (TS) Volatile Solids (VS) Suspended solids (SS) Dissolved Solids (DS)
Standard Method 4500 – H B. 2520 B. 2150 B. 5210 D. 5220 B. 5310 C. 4500 – SO4 – E. 4500 – NH3 C. 4500 – Norg. B. 4500 – Cl B. 3111 Β. 3111 Β. 3111 Β. 3111 Β. 3111 Β. 5530 D. 4500 – P D. 2540 B. 2540 E. 2540 D. 2540 C.
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4.9.3 Groundwater monitoring system The groundwater monitoring system serves two purposes:
to demonstrate that the landfill is not causing significant degradation of groundwater
if groundwater composition has been degraded, to evaluate the character, magnitude and extent of contamination of the groundwater resource.
There will be two types of groundwater monitoring wells:
down-gradient wells
up-gradient wells
Up-gradient wells will show the pre-existing condition of the groundwater prior to any effect of the landfill. Down-gradient wells will be located downstream in order to detect any sign of leachate leaking out of the landfill. The up-gradient wells will be sampled along with the downgradient wells. This will provide information on seasonal or long-term trends in the groundwater. Even though the condition of the groundwater may change over time as a result of natural or other (not related to the landfill) affects, however by monitoring both the upgradient and down-gradient wells, any landfill related change can be identified. The parameters measured as well as the frequency of sampling are shown in the following table: Table 4-22: Parameters and frequency of measurements for groundwater monitoring
PARAMETERS Level of groundwater Groundwater composition
FREQUENCY Operational Period Every 3 Months Every 3 Months
Aftercare period Every 6 months Every 6 months
A system of monitoring boreholes will be installed (one (1) up-gradient and two (2) downgradient) as shown in the relevant drawing. The sampling must be done according to the ISO 5667-11 while the chemical analysis should be according to the “Standard methods for the examination of water and wastewater” by AWWA, APHA, WEF, as shown in the following table: Table 4-23:Standard methods for the examination of water and wastewater
No 1 2 3 4 5
PARAMETER pH Conductivity Odours B.O.D. C.O.D.
Standard Method 4500 – H B. 2520 B. 2150 B. 5210 D. 5220 B. 87| P a g e
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No 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
PARAMETER T.O.C SO-4 Ammonium (NH4-N) Organic N Cl Zn As Cd Cu Ni Phenols Phosphate Total Solids (TS) Volatile Solids (VS) Suspended solids (SS) Dissolved Solids (DS)
Standard Method 5310 C. 4500 – SO4 – E. 4500 – NH3 C. 4500 – Norg. B. 4500 – Cl B. 3111 Β. 3111 Β. 3111 Β. 3111 Β. 3111 Β. 5530 D. 4500 – P D. 2540 B. 2540 E. 2540 D. 2540 C.
Technical specifications for the Groundwater monitoring wells Groundwater monitoring wells will be constructed via drilling. The drilling diameter will be no less than 8.5 inches. After drilling the borehole will be broadened and be equipped with a pipe of hot dip galvanized steel. This pipe will bear holes from the borehole bottom up until 2m before the surface. The last 2m will have no holes. Inside the galvanized steel pipe, a stainless steel pipe (piezometric pipe) will be placed. The piezometric pipe shall consist of a sedimentation pipe, a filter, over filter full pipe with protective cap and a protective concrete block. The sedimentation pipe is part of the piezometric pipe that is placed to collect all tiny fractions coming into the construction. It is a full pipe, plugged from underside and located at the bottom of the piezometric construction. The filter is the perforated part of the piezometric construction, with holes of at least 10 mm of diameter. The part of the construction above the filter to the ground surface is a full pipe closed on the top with a standard metal cap and secured with a protective cover. In order to make piezometers visible, so as not be damaged at the ground planning and the deposits compaction processes, the piezometric constructions stick out at least 1.0 m from the ground, and are painted in vivid colours. In order to protect piezometric constructions from damages, a concrete block is founded around them. The interspaces between the drilling walls and the galvanized steel pipe are filled with gravel.
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The interspaces between the galvanized steel pipe and the piezometric pipe, in the zone of the sedimentation pipe, the filter and the pipe above the filter, are filled with quartz granular material, while the other part towards the ground surface is buffered with fragmented, dusty and clay material.
4.9.4 Surface water monitoring system Frequent visual inspections will be made in the site and in the river. Evidence of degradation may include obvious signs, such as dead or unhealthy flora and fauna, visible leachate pools or streams, unnatural water clarity or colour and unusual odours. Besides the visual inspections, surface water should be checked quarterly in the operating phase and every six months in the aftercare phase. During those sampling rounds, field measurements at representative surface water locations should be taken, measuring the parameters. The suggested sampling points are two for the ditch of the drainage collection system of the cell The first sampling point will be in the higher point of the ditch while the second one will be at its discharge point. This way it will be easy to monitor possible leachate leakages. Morover in accordance with the monitoring programme of the Ibar river it is suggested to monitor the river below the landfill. In order to do this the operator has to identify the existing parameters within the river.
4.9.5 Biogas monitoring system Monitoring of biogas is a twofold procedure that involves:
Knowledge of the produced biogas volume and composition
Monitoring of possible biogas migration
The first goal of biogas monitoring will be achieved via a portable landfill gas measurement device (landfill gas analyser). This device shall be equipped with gas probes and a data logger (for data storage and uploading to a PC). Measurements will take place at landfill gas wells and will at least include: pressure, methane content, carbon dioxide content and oxygen content. The amount of produced biogas can be recorded via the flare. Other constituents of biogas may also be monitored by adding probes to the analyser such as hydrogen sulphide (indicative also of odors), hydrogen, nitrate, etc. For further analysis of compounds such as hydrocarbons, non methane organics, etc., sampling and use of air chromatography is required. The second goal regarding landfill gas migration requires specific procedures to be established for its assessment. The need for gas migration monitoring comes from its flammability and explosive potential. The purpose of gas migration monitoring is to ensure that the biogas does 89| P a g e
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not migrate and accumulates in on-site structures or to off-site locations, in concentrations that could be hazard for humans or property. The concentration of methane gas should not exceed 25% of the Lower Explosive Limit (LEL) in the landfill structures and 100% of the LEL at the property boundary. The LEL for methane is 5% (methane/air) For inspection of possible migration, boreholes of small depth (not exceeding 6 m) are drilled around the landfill basin. The distance between boreholes is about 150m. Each borehole will have a diameter of 6’’ and will be piped with a hot dip galvanised steel perforated pipe of 2’’ diameter. A drawing shows the detailed construction and installation of the biogas monitoring wells. Samples will also be taken with the use of the gas analyser from these monitoring wells to assure that landfill gas does not migrate from the sides of the landfill basin. There will be constructed 10 biogas-monitoring wells around cell. Flare unit To protect the operative personnel and the equipment related to the gas flare unit, warning systems regarding gas presence have to be placed. The warning system will command the shutdown of the gas feeding system, which will shut off the exhaustion, in case critical values of the methane and/or oxygen content are reached, as presented below. Gas critical value Shut down value
Methane (%) < 30 < 25
Oxygen (%) >3 >6
Maximum gas concentration at work place Before and during the operation of the degasification system, in closed spaces (manholes, collection stations), the concentration of methane, oxygen and carbon dioxide have to be measured. All closed spaces have to be equipped with natural ventilation devices and the enforced legislation regarding the operation procedures in this type of working spaces has to be strictly respected. Precaution measures for personnel The concentration of methane gas should not exceed 25% of the Lower Explosive Limit (LEL) in the landfill structures and 100% of the LEL at the property boundary. The LEL for methane is 5% (methane/air). For that reason, gas control units for inspecting explosive methane concentrations will be installed in buildings where personnel work. Such a unit is equipped with detectors transmitters connected to a system of alarm signaling that is activated, when the methane concentration exceeds the LEL. 90| P a g e
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4.9.6 Settlements monitoring system The behaviour of the waste body is a critical parameter for the restoration/rehabilitation of the landfill areas that have reached their final height. Therefore, the amount of settlements (waste “pile” height reduction, due to decomposition) is an important parameter and record keeping regarding this phenomenon is essential, especially if light constructions are to be placed on the site after rehabilitation. In order to measure settlements, the so-called “settlement plates” are installed on the waste surface (in the areas where final waste height has been reached). These plates include a steel plate (4 mm thickness) where a steel pipe (2’’ diameter) is welded. The base of the settlement plates is installed 0.5 m underneath the final surface of the cell, secured in its position by a layer of concrete (thickness 20 cm). The iron pipe is used to measure height reduction. The elevation of the pipes is measured and compared with the elevation of stable points of the plant (reperes). The measurements should be done every month at the beginning of the rehabilitation works and till their completion, every 3 months the next year and every 6 months till the expiration of the aftercare period of the landfill.
4.9.7 Monitoring of water conditions – Recording of data The meteorological parameters, will be based on the data from the nearest meteorological station. The parameters to be recorded during the operation lifetime of the SL are:
Volume of Precipitation:
daily
Temperature (min, max, 14.00 h CET):
daily
Direction and force of prevailing wind:
daily
Evaporation
daily
Atmospheric Humidity (14.00 h CET)
daily
At the aftercare stage, the frequency of the above mentioned recordings could be reduced for all the parameters, according to the following:
Volume of Precipitation:
daily (added to monthly values)
Temperature (min, max, 14.00 h CET):
monthly average
Direction and force of prevailing wind:
not required
Evaporation:
daily (added to monthly values) 91| P a g e
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Atmospheric Humidity (14.00 h CET):
monthly average
4.9.8 Volume and composition of incoming waste and soil material The operator of the plant must keep records for a series of information collected during the weighing of the collection vehicles in the entrance of the landfill. This information is:
Title and address of the owner of the vehicle, full name and telephone number of the responsible.
Title and address of the producer of the waste, full name and telephone number of the responsible.
Source of waste
Type of waste
Weight of waste
That means that statistical records will be kept for the volume and the type of the incoming waste according to their source for the whole period of operation of the landfill. In order to avoid the reception in the landfill of non-acceptable waste and for statistical reasons as well, two sampling inspections of incoming waste must be executed every day. In every inspection the following information will be registered:
Date and time of inspection
Source of incoming waste
Vehicle and driver’s necessary data.
Observations of the inspector
The above-mentioned inspections will give information for the composition of the incoming waste and its variation through the year and according their source. Finally, during the entrance of the transportation vehicles, the volume the composition and the source of the incoming soil material will be registered as well.
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4.10 GENERAL INFRASTRUCTURES - UTILITIES 4.10.1 Introduction The proper operation of the SL depends on the right installation of utilities and structures. All the necessary infrastructure for the appropriate operation of the SL have been included, namely:
•
Main entrance - fencing
•
Weighbridge building
•
Weighbridge
•
Sampling area
•
Administration building
•
Maintenance building
•
Open parking for personnel and visitors
•
Tire washing system
•
Internal Roads
•
Fire Protection zone in the perimeter of the landfill
•
Fire fighting system
•
Electrical system
•
Green area
4.10.2 Main entrance - fencing The fence will cover the whole perimeter of the facility. It will be made of steel net (the length of the net rings > 40x40 mm) or similar. The height of the fence will be at least of 2,5 m above the ground. As long as the conditions of soil allow, the fence will be dug in approximately 20 cm in the ground in order to restrict animals from trespassing. The entrance gate will be of the same height as the fence, equipped with closing system, the length of the door will be 7 m. The entrance gate will be consisting of two doors. At the gate a sign with the main information of the site will be placed (operator, type of facility, working hours, phone, etc.). The fence will be supplemented with a green zone of at least the same height. 93| P a g e
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4.10.3 Weighbridge building The weighing building is located next to the weighbridge of the facility. Weighbridge Building has dimensions 5x2,45 m and a surface of 11.62 m2. The building will have office premises and WC. The structure is one fabricated container which is fixed above the ground where as main support are metal columns. Concrete elements should be made with concrete class C30/37 or as per structural analysis which will be made. Also the concrete slab should have the thickness not less than 20 cm. Quality of rebar should be S 400/500. Doors and windows are made with PVC materials The building shall be equipped with a desk where the necessary equipment (for weighing of the incoming vehicles and recording of data) is to be installed.
4.10.4 Weighbridge It will be installed at the entrance gate. The indicative capacity will be 60 tn and its size approximately 55 m2. It will be equipped with external weighing terminal for registration of all necessary data and information. The supply must include a fully operational weigh bridge with equipment and registration system, installed and calibrated. The supply must also include all necessary signal and power supply cables between the weighbridge and the operator's office.
4.10.5 Sampling area It is located after the weighbridge and is used for taking waste samples in order to identify whether they should enter the central waste management facility. Its surface is approximately 80 m2.The sampling area will be fenced and covered by shed. The floor of the area will be made of asphalt.
4.10.6 Administration building Administrative building has a surface of 51.94 m2. The building indicatively will consist of the following areas:
Control Room Utilities area-Generator Reservoir area Warehouse WC
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The structure is one floor building where the structure is build using concrete columns as main structure supporter. Inner walls are constructed using gypsum plates with thermo insulation. Outer walls are made with metal sheet sandwiches so called polyurethane side panels. Also the roof is covered with the same materials. Internal walls will be painted after rendering with two layers of colour. Foundations are made with reinforced concrete slab with thickness more that 15cm with concrete class of C25/30. The columns are with dimensions 150 x 10mm and concrete class C30/37 or as per structural analysis which will take place. Qwualitry of rebar should be S 400/500. Doors and windows are made with aluminium material.
4.10.7 Maintenance building The facility is planned for regular functioning of the landfill it is located close to the administrative building. The maintenance building covers surface of approximately 105 m2916,010x6,52 m). The building will include facilities such as workspace, garage, warehouse, cart washing plateau, etc. The structure is one floor building where the structure is build using steel structure. The main colums are SHS 250 x 6,5mm and the beams are square steel profiles with dimensions RHS 250 x 150 x6,3 mm. free height is 6,5m. Outer walls are made with reinforced concrete strips with concrete class C25/30 with dimensions 110x50cm. Above the foundation strips and compacted gravel layer an reinforced concrete slab will be fixed with thickness 20cm of C25/30. Quality of rebar should be S 400/500. The structure will also have a ramp for easy access.
4.10.8 Water tank Water tank has dimensions 8.15x6,75 m and a surface of 55.01 m2. The water reservoir has two chambers:
Fire Water Tank with capacity of 51.45 m3 and Water irrigation chamber with volume 31.55 m3.
At one side of building a space with dimensions 2.52x6,75 cm designed for installations of the equipment. The structure is one floor building from concrete walls. Bottom slab is 30cm thick, side walls of 25cm and top slab of 20cm thick. Inner walls will be constructed using high quality concrete and high waterproof component. Outer walls should be plastered and painted. Also top slab need to be waterproofed with all the necessary layers. Doors and windows are mad with metal materials. 95| P a g e
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4.10.9 Parking for personnel and visitors The vehicles of the visitors and works of the landfill area (including the administration building and the maintenance building) will be parked in an open parking next to the administration building. The capacity of the parking should be at least 10 vehicles.
4.10.10
Tire washing system
The purpose of the tire washing system is to wash out the tires of the waste collection vehicles from the mud of the landfill. It is located in a widening of the internal road, just before the entrance area in the exit direction, and consists of two subsystems: washing subsystem equipped with: o
movement monitoring system which starts the operation of the system
o
washing water nozzles
o
heavy duty grating for the collection of wastewater
o
feeding pump for the washing water
o
filter
o
piping with necessary valves
water recycling and sludge removal subsystem equipped with: o
separation of solids – clean water tank. The separation is accelerated through a PVC pipe, which leads the wastewater to the bottom of the separation tank.
o
weir of clean water overflowing into the clean water tank
o
excess sludge removal piping with isolation valve and hydraulic equipment
The tire washing system is equipped with water nozzles, which create water pressure jets with appropriate pressure for the washing of the tires. The wastewater generated from the tire washing will collected in a tank (which is part of the equipment) and it will be regularly transferred to the wastewater collection tank in order to be treated in the leachate treatment plant. The structure itself is concrete made with concrete clas C30/37 and rebar S400/500. Concrete thickness for slabs and walls is 20 cm.
4.10.11
Fire Protection zone:
It will be located in the perimeter of the landfill having a width of 8 meters. In this zone no vegetation or infrastructure is allowed in order to avoid the expansion of a possible fire inside the landfill. 96| P a g e
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4.10.12
Green areas
Inside the fencing and perimetric to the facility tree plantation is foreseen for the visual isolation of the site (average width of the plantation 3 m). An appropriate irrigation system will be developed, which if allowed will utilize the treated water exiting from the wastewater treatment plant.
4.10.13
Fire fighting system
A fire fighting network will be developed, which shall cover the whole area of the facility. The system will be connected with appropriate water tank, of sufficient volume, which will be monitored in order to always be full of water
4.10.14
General formulation of the area
For the communication among the infrastructure and their protection from corrosion of the soil from the rainfall the area will be formulated and a corridor of at least 1 m wide will be constructed perimetrically to the buildings. The corridor is made of concrete armoured with wire grid with no coating. Moreover the run off of the rainwater from inclined green areas from the buildings is foreseen. The general formulation include also footpath connecting the buildings and the infrastructure.. The paths are constructed according to the ground slopes and the rainwater is drained. Steps are also constructed according to the height differences.
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4.11 ROAD WORKS 4.11.1 Introduction Road design is important for the vehicles access to the cells and all the landfill site’s facilities. The internal roadways circulation is used mostly from heavy vehicles so the roadway must be built in a way that can ensure the easy movement.
4.11.2 Temporary roads No traffic is allowed directly on top of drainage layer in the landfill cells or on the intermediate dikes. The landfill staff shall establish and maintain access ramps and temporary roads over the dikes and the drainage layer with a min. thickness of 0.5 m ensuring a min. distance from wheelbase to the polymer liner of min. 1.0 m Temporary access ramp over lined areas,
Leachate Drainage layer Polymer Liner Geological Barrier (Clay liner)
The landfill staff shall establish and maintain access ramps and temporary roads over the already deposited waste inside the landfill cells, securing the safe access of waste delivery trucks for unloading in the cells. The roads can be established using gravel and/or stone, crushed mineral debris from construction and demolition waste or moveable plates of concrete or steel. The thickness of compacted waste below the temporary roads shall be at between 22.5 m
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4.11.3 Internal road Internal road is the road beginning from the entrance of the central waste management facility, and is built at first to reach the landfill’s cells and at the same time to provide access to the main facilities areas. The road will be constructed with 6m, one lane in each direction. The road can be extended to provide access to the waste treatment facilities that will be developed on site . The design speed of the road is 30km/h. 4.11.3.1 Horizontal and Vertical Alignment – Typical Cross-Section The proposed cross slope at straight sections of roads is 2.5% and for curved sections 5.0%. The maximum radius of horizontal curves, used on the internal road, is 40.0 meters and the minimum radius is 30.0 meters which are acceptable due to low travelling speeds. The maximum vertical slope that is proposed is 8% and both sag and crest vertical curves have a proposed radius of 800m. 4.11.3.2 Road layers Pavement of roads and other areas of heavy traffic are proposed to be constructed by laying and compacting of the following layers:
ballast foundation (30 cm)
crush stone foundation (15 cm)
asphalt concrete BA16 – wear layer (4cm)
asphalt mixture AB2 – base layer (6cm) 99| P a g e
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4.11.3.3 Internal Road Layers The road construction includes the following works according to standards:
Sub-base construction: Technical Specification Ο150
Base construction: Technical Specification Ο155
Shoulders construction: Technical Specification Ο155
Asphalt greasing: Technical Specification A-201
Asphalt base layer: Technical Specification Α-260
High-density asphalt layer: Technical Specification Α265
4.11.3.4 Embankments construction The material to be used for the construction of the road embankments should meet the requirements for excellent to good soil material, according to AASHTO. In order to achieve the shear strength parameters of c = 5KPa and φ = 35o, the granular material should follow in the A-1-a (materials consisting predominantly of stone fragments or gravel, either with or without a well graded soil binder) or A-1-b (materials consisting predominantly of coarse sand either with or without a of well- graded soil binder) classification. The material should be well graded with maximum size fragment of 15cm.
4.11.4 Access Road The road connecting the main road and new designed Landfill passes through open hill terrain which limits us the possibility to have the shortest path. Due to this the length of the road is increased in order to maintain the minimum slope possible. The length of the road is 2+180.00 m. The width of the road is 3.5 m and the road will be used only in one direction alternatively. At every app. 200 m we have designed a wider road which will allow the tract to move alternatively. On both sides of the road shoulders are 1 m wide for safety reasons. Steel barriers are foreseen on most dangerous part which will protect trucks during winter season. The road dimensions are designed as this due to budget limitation and cost construction due to stone area.
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Technical elements taken into consideration during design:
Moving Speed Width of the road Longitudinal minimum road slope Longitudinal maximum road slope Cross section slope Cross section slope crossing curves Minimal passing curve Minimal radius Maximum radius
V=10-35 km/h B=1x1.75=3.50 m 7.48 % 0.22 % 2.5 % 2.0-8 % 10 m 15 m 200 m
Road cross section is 1+3.5+1+widening
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Since the terrain is mostly rock material, this material can be crushed and used for construction. The road construction will be made as per layer bellow: Filling of sub-base with selected material from excavation with thickness as per design and compaction of layers at each 30 cm. Compaction module should be 80MN/m2 After cut and fill is finished the terrain should be compacted. Compaction of sub-base with compactor until module of compaction achieves the 80 MN/m2. When compaction module is achieved than the first layer with crushed stones with grain fraction 0-64 mm thickness should be fixed. The thickness of this layer after compaction should be not less than 200 mm.Compaction has to be done with 12tones compacter to reach the compaction of the layer up to 100 Mpa. Above first layer with crushed stones with grain fraction 0-64 mm thickness than a new layer of crushed stone should be fixed with dimensions 0-31.5 mm. The thickness of this layer after compaction should be not less than 150 mm. Compaction has to be done with 12tones compacter to reach the compaction of the layer up to 120 Mpa. Material to be used for the road layers cannot consist organic subjects, soil or sufficient quantity of slime. Quantity of particles smaller than 0.02mm in the mixture max 0.8%. If particles smaller than 0.02mm are up to the mentioned percentage they can be tolerated because it does not influent on caring capacity of the road base which is going to be influenced by frost, underground water, humidity change of climate. Crushed stone can consist max 7% of the grains which are produced from soft stones. Size of the grains should not be reduced with the compaction. Humidity of material should be regulated in that way to reach the maximum compaction. All parts of the base, i.e. up to 0.50 m from the edge of the shoulder must have at least 102% proctor density. The surface of the base is to be specially compacted. Weather conditions are to be taken into consideration when testing the load bearing capacity of the gravelled surface. The compulsory values must be attained within one or two days of drying, depending on the air temperature.
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Road side slopes towards the open ditches should be 1:1.5 in all cases. In cases when we have fill the slope remains the same. At terrain cutting the slope ratio should be 1:1 if not other slope ratio will be required by supervisor during construction. At station where are shown in design the concrete tube should be fixed with diameter d=500 mm. The required concrete class should be C-25/30. The pipes should be laid over compacted terrain which is laid with gravel 0-31.5 and thickness 20 cm. Compaction of this layer should be Mn=40 Mpa. Outlet and inlet should be done with reinforced concrete. Bitumengravel layer should be laid above bituminous layer as per technical specification. Thickness of base course should be 8 cm. Final layer of asphalt should be minimum 4 cm after compaction. All specifics of construction should be done according to Technical Specifications.
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5
LANDFILL CLOSURE AND AFTERCARE
5.1
INTRODUCTION
The closure of a solid waste landfill has a significant impact on the county's solid waste management plan. Alternative disposal facilities must be in place and operational when a landfill is closed. This requires close cooperation between the landfill owner and the region. The development of alternative disposal facilities can require a long-term effort, and requires that closure of existing facilities be foreseen and planned several years in advance. This section includes the description of the closure, capping and aftercare of the new landfill in Savina Stena, according to the specifications of the Kosovar legislation. Moreover the section addresses also the issues of future land use.
5.2
LANDFILL CLOSURE
The date of closure is based on an estimate of the waste stream volume and remaining available capacity in the landfill. However, the uncertain nature of the waste stream and remaining capacity make closure date estimates very approximate until the landfill approaches the end of its active life. Then the closure date can be estimated accurately enough to allow the owner to estimate the date of closure several months in advance. At closure, the owner should post a sign that indicates the site is closed and list alternative disposal facilities. Records and plans specifying solid waste quantities, location and periods of operation will be submitted to the local land use/zoning authority and be made available for inspection. According to Administrative Instruction no.10/2007 (Article 18): Landfill will be considered as closed, when the Ministry think that accomplished all obligations and requests of this instruction by the landfill operator, and the ministry will issue the writing decision to close this landfill; Landfill operator, even after the closing procedure, he is responsible for maintain, supervising and controlling the landfill according to the determinate period on article 21, ofthis instruction
5.2.1 Landfill capping Objectives of capping The main objectives in designing a capping system are to:
Minimize infiltration of water into the waste;
Promote surface drainage and maximize run off;
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Control gas migration; and
Provide a physical separation between waste and plant and animal life.
The capping system normally includes a number of components which are selected to meet the above objectives. The principal function of the capping system is to minimize infiltration into the waste and consequently reduce the amount of leachate being generated. According to Administrative Instruction no.10/2007 (Article 19): Last cover of landfill involve the following levels: 1. First level, mean soil level with minimal layer thicknessl0 cm, which is using for covering, flatting and landfill form; 2. Second level is content from geo- membrane, minimal layer thickness 2.5 mm; 3. Third level is content from two sub levels of compacted clay, minimal layer thickness from 25 cm (both levels 50 cm) and; 4. Fourth level and the last one content adequate soil (it is preferred humus soil) for recultivation which can have the minimal layer thickness 40 cm. At the same Article it is mentioned that “Landfill operator during the closing process must demount all equipment and objects which will not be in function of landfill” In Article 20 it is mentioned that: 1) Re-cultivation process starts after the last soil level over the landfill wastes. 2) Re-cultivation should be in harmonization with spatial landscape where is located the landfill, and its adaptation in order of using it for recreation, foresting and agriculture. 3) On the closed landfill its not allowed the constructions of the inhabitation objects Finally in Article 21 it is mentioned that: 1) The period of monitoring, after closing andre-cultivationof landfill,mustcarryout until it is considering that the negative impact on environment will be the less 2) The period of monitoring must carry out in duration from 30 years after the landfill close; Components of the capping The surface sealing of the Savina Stena SL, will consist of the following layers (from bottom to top):
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Support layer (Levelling layer)
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Gas drainage layer (Collecting the landfill gas)
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Mineral lining layer 105| P a g e
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Protection Geotextile
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Rainwater Drainage layer (The lining layer for the drainage water)
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Separation Geotextiles as protective layers
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Top soil cover (vegetal and subsoil)
The proposed specifications regarding the capping layers have been modified slightly, but on the side of safety. The above-mentioned layers are described in the following paragraphs. 5.2.1.1
Support layer
A support layer shall be constructed in top of the final waste terrain, in order to flatten the top layer of the landfill and prepare the terrain for the installation of the following surface sealing layers. The support layer thickness will be 0.3m. The temporary cover of the landfill will be used as the lower part of the support layer. The soil allows the gas to move and takes over the static and dynamic charges that appear with the lining system. The support layer must not contain organic components (wood), plastic materials and concrete with tar content, iron/steel and metals. The support layer must be homogenous and have endurance at constant efforts. At the top of the layer the surface must be flat and levelled. Attention should be paid at the content of calcium carbonate which must not exceed 10% of the mass as well as at the mass of the maximum length particles, which must not exceed 10%. Table 5-1:Technical Specifications of support layer
CHARACTERICS Type of material Thickness Elasticity Module Permeability coefficient
REQUIREMENT Soil 0.3 m 40 MN/m2 1x10-4 m/s
Restrictions
5.2.1.2
Calcium Carbonate
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