Report Sewerage Submission MX-1.doc

MX-1 Development Sewerage Report 1.0

Introduction The proposed development indentified as MX-1 is part of the new Kwasa Damansara Township which cover a total area of 64.30 acres located in Sg. Buloh, Selangor Darul Ehsan . The proposed development area is located near of Rubber Research Institute Malaysia Malaysia (RRIM) as shown in Figure 1.0 below. Project MX-1 is an integrated residential and commercial development that will be the town centre of the proposed Kwasa. MX-1 location is extremely strategic with the advantage of a main road frontage and two MRT stations traversing the area. Overall, the development would gain from the socio-economic benefits that include commercial, retail and residential developments that make the location a thriving hub of activity.

64.30 Acres

Institut Piawaian Getah Malaysia, Rrim

Boundary Proposed Development Area MX-1

Figure 1.0: Layout Plan

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MX-1 Development Sewerage Report

2.0

Proposed Sewerage System There are 10 plots of proposed area development as shown in figure 2.0 below with estimated demand of 42,192 P.E. For this development we proposed sewer pipes reticulation connecting from the development manhole that collect all the sewage and then planned to discharge to the nearest external sewer main manhole. All the sewage discharge using is using gravity system.

Figure 2.0: Plot Area

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MX-1 Development Sewerage Report

The proposed development area is fall under Commercial and Residential usage and the waste water demand computed for this usage is mainly for household, commercial area, and office use. The estimated Population Equivalent (P.E) calculated for this development is 42,192 P.E. The detail of the estimated PE is shown in Appendix A. The summary of the above is as follows:

Description

3.0

Population Equivalent (P.E)

Plot A & B

3,544

Plot C

8,503

Plot D

1,254

Plot E

6,215

Plot G

5,225

Plot H

9,241

Plot I

3,850

Plot J

4,360

Total

42,192

Design Criteria & Standards for Sewerage System Primary objectives in the design of the sewerage system are to optimize sewerage flow by gravity and the length of sewer required while satisfying current and future demands of the proposed development. Hence, the concept of the proposed sewerage system is largely governed by the proposed platform levels and existing ground to topography. The following guidelines have been adopted for the design stage of the sewerage system. i)

MS 1228: 1991 Code of Practice for Design and Installation of Sewerage System.

ii)

Guidelines for Developers on the design and installation of sewerage system issued by Director General, Sewerage Services Department, Ministry of Housing and Local Government.

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MX-1 Development Sewerage Report iii)

Malaysia Sewerage Industry Guidelines issued by Suruhanjaya Perkhidmatan Air Negara (SPAN)

Where the above guidelines do not adequately cover certain aspects of the design, reference was made to both British and American Standard and Guidelines. 4.0

Design of Gravity Sewer Systems The sewers reticulation systems for Sub-Catchments are generally defined by the natural landform catchment area and to be served by a network of lateral sewer, which are connected at the down street and to a collector sewer. This in turn will be connected to the trunk sewer system for the sewer catchment. The sewers have been designed for gravity flow in such as not only to reduce the capital cost of construction but also the operations and maintenance cost of having a pumping station. Further more, the design of sewers also taken into consideration the follows: 

Carrying capacity: the design flow and organic loading should include infiltration flow allowances.



Infiltration: Infiltration shall be minimized by the proper selection of construction technology and materials, proper supervision of construction and field testing of the components for water-tightness.



Economy: Sewer length shall be kept as short as possible but taken into account allowance for future development.



Hydraulics: the most economical design for sewer gradients is obtained when they follow natural falls of the ground, which would also take into account the possibility for future development.



Depth: the nature of the ground, presence of ground water, proximity of foundations and services shall be taken into account.



Size: The size shall be planned to meet the planned carrying capacity of the locality.



As far as possible sewers are designed to follow the natural topography of the land. They will be laid at such gradients to that velocities in the sewers will keep the solids

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MX-1 Development Sewerage Report in the sewage in suspension or at least in traction and also to prevent scouring of sewers by the erosive action of suspended matter. 

Manholes will be provided at changes in sewer diameter, directions, gradients at bends and junctions.



Drop manholes shall generally be avoided but where required, the structure shall be provided with means to clean out materials that might lodge in the drop pipe.



Within the CUT, all pipeline, bend etc shall be made by Ductile iron pipes (D.I) with proper plint to ensure pipeline can be installed to the gradient required. For external pipeline outside of the building, Clay pipes or and Concrete pipes to be adopted

4.1

Hydraulic Design of Sewers (a)

The hydraulic design of sewer shall be based on the daily sewage production value of 225 liter/PE.

(b)

The recommended minimum values of population equivalents (P.E.) are given as Table 3.

(c)

The determination of discharge capacity of gravity pipelines shall be made either using the Manning’s formula or Colebrook & White formula. However the discharge capacity calculation in this submission is based on Colebrook and White method.

By using Manning’s formula: V

=

1/n R2/3 S1/2

Where, V

=

mean velocity, m/s

N

=

Roughness Coefficient (Refer table C1 – 0.017 for VCP & 0.016 for RCP(without PVC lining))

S

=

Slope of total energy line

R

=

Hydraulic radius (m/m)

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MX-1 Development Sewerage Report By using Colebrook & White formula: V

=

-2 (2gD) Log [(ks/3.7D) + [(2.51/D(2gDi))]

Where, D

=

diameter of pipe (m)

g

=

gravitational acceleration = 9.81 m/s2

I

=

Hydraulic gradient (%)

ks

=

Linear measure of roughness (m)

V

=

mean velocity of flow (m/s)



=

Kinematics viscosity (1.4 x 10-6 m2/s for water at 15C)

Assumptions used ks

=

0.6mm when velocity is greater than 1 m/s (conservative design)

V

=

Minimum / maximum velocity at full flow (m/s)

Hence, Q

=

AV x 103

A

=

Cross sectional area of flow

V

=

Mean velocity of pipe (m/s)

Q

=

Discharge (l/s)

and

4.2

Minimum Velocity at full flow

=

0.8 m/s

Maximum Velocity at full flow

=

4.0 m/s

Peak Flow Factor Peak flow factor (PFF) = 4.7 x p-0.11, where p is estimated PE in thousand

4.3

Flow Peak Flow

4.4

= (PFF x P.E. x 225 l/c/day) l/d

Example of Calculation

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MX-1 Development Sewerage Report Pipe size

=

225mm dia. VCP

Pipe Gradient

=

1: 250

Colebrook - White Equation

V

=

-2

=

0.6mm

g

=

9.81 m/s2

i

=

1/250

V

=

-2

=

0.82 m/s

=

AV x 103

Q

Log

“Conservative Design”

Log

*(0.82)*103

= =

32.70 L/s

Manning’s Equation Manning Equation,

V=

R 2/3 S ½ n

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MX-1 Development Sewerage Report

where, V = velocity (m/sec) S = hydraulic gradient R = hydraulic radius n = Manning coefficient

Typical ‘n’ values for various types of sewer pipes are presented in Table 1 below: Table 1: Typical Manning Coefficient, ‘n’ Manning Coefficient, n Good Condition Bad Condition 0.012 0.015 0.011 0.013 0.012 0.015 0.010 0.017 0.012 0.016

Material Uncoated cast-iron Coated cast iron Ductile iron Vitrified clay pipe Concrete Example,

D = 225mm, J = 0.1125m, n = 0.010 (Good Condition) V

= (A/P) 2/3 (1/250)1/2 0.01 2

= (ЛJ /2ЛJ)2/3(1/250)1/2 0.01 = 0.93 m/s Hence,

0.8 m/s < V < 4.0 m/s

OK

Table 3 – Recommended Population Equivalent Type of Premises / Establishment Residential Commercial

Population Equivalent (Recommended) 5 per house 3 per 100m2 gross area

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MX-1 Development Sewerage Report Entertainment/recreational centers, Restaurants, cafeteria, theatres Schools / Education Institutions: -

Day schools / Institution

0.2 per student

-

Fully residential

1 per student

-

Partial residential

0.2 per non-residential student

Hospital Hotels with dining and laundry facilities Factories, excluding process water Market (wet type) Market (dry type) Petrol kiosks / Service stations Bus terminal Taxi terminal Mosque Church / Temple Stadium Swimming pool / Sports complex Public toilet Airport

1 per residential student 4 per bed 4 per room 0.3 per staff 3 per stall 1 per stall 15 per toilet 4 per bus bay 4 per taxi bay 0.2 per person 0.2 per person 0.2 per person 0.5 per person 15 per toilet 0.2 per passenger bay

Laundry Prison Golf Course

0.3 per employee 10 per machine 1 per person 20 per hole

Source:

Guidelines for Developers on the Design and Installation of Sewerage Systems, Ministry of Housing and Local Government

Table C1: ‘n’ Value Surface Uncoated cast-iron pipe Coated cast-iron pipe Commercial wrought-iron pipe, black Commercial wrought-iron pipe, galvanized Smooth brass and glass pipe Smooth loch bar and welded "OD" pipe Riveted and spiral steel pipe Vitrified sewer pipe Common clay drainage tile Glazed brickwork Brick in cement mortar; brick sewer Neat cement surfaces Cement mortar surfaces Concrete pipe Wood stave pipe Palnk flumes Planed

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Best

Good

Fair

Bad

0.012 0.011 0.012 0.013 0.009 0.010 0.013 (0.010) (0.011) 0.011 0.011 0.012 0.010 0.011 0.012 0.010

0.013 0.012a 0.013 0.014 0.01 0.011a 0.015a 0.013a

0.014 0.013a 0.014 0.015 0.011 0.013a 0.017a 0.015

0.015

0.012a 0.012 0.013 0.011 0.012 0.013 0.011

0.014a 0.013a 0.015a 0.012 0.013a 0.015a 0.012

0.017 0.015 0.017 0.013 0.015 0.016 0.013

0.010

0.012a

0.013

0.014

0.015 0.017 0.013

0.017

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MX-1 Development Sewerage Report Unplanned With battens Concrete-lined channels Cement-rubble surface Dry-rubble surface Dresses-ashlars surface Semicircular metal flumes, smooth Semicircular metal flumes, corrugated Canals and ditches Earth, straight and uniform Rock cuts, smooth and uniform Rock cuts, jagged and irregular Winding sluggish canals Dredged-earth channels Canals with rough stony beds, weeds on earth banks Earth bottom, rubble sides Natural-stream channels 1. Clean, straight bank, full stage, no rifts or deep poles 2. Same as (1), but some weeds and stones 3. Winding, some pools and shoals, clean 4. Same as (3), lower stages, more ineffective slope and sections 5. Same as (3), some weeds and stones 6. Same as (4), stony sections 7. Sluggish river, reaches, rather weedy or with very deep pools 8. Very weedy reaches

0.011 0.012 0.012 0.017 0.025 0.013 0.011 0.0225

0.013a 0.015a 0.014a 0.020 0.030 0.014 0.012 0.025

0.014 0.016 0.016a 0.025 0.033 0.015 0.013 0.0275

0.015

0.017 0.025 0.035 0.0225 0.025

0.020 0.030 0.040 0.025a 0.0275a

0.0225a 0.033a 0.045 0.0275 0.030

0.025 0.035

0.025 0.028

0.030 0.03a

0.035a 0.033a

0.040 0.035

0.025 0.030 0.033

0.0275 0.033 0.035

0.030 0.035 0.040

0.033 0.040 0.045

0.040 0.035 0.045

0.045 0.040 0.050

0.050 0.045 0.055

0.055 0.050 0.060

0.050 0.075

0.060 0.100

0.070 0.125

0.080 0.150

0.018 0.030 0.035 0.017 0.015 0.030

0.030 0.033

* Values commonly used in designing

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