FLSmidthGravityBeltThickener Brochure

FLSmidth EIMCO® Belt Concentrator Sludge Thickener

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FLSmidth EIMCO® Concentrators Compression Filtration Zone After the gravity zone, a mild compression zone squeezes additional liquid from the filter cake prior to discharge. The compression blanket consists of an adjustable plate that presses against the cake, retarding the sludge, creating a mild pressure zone prior to discharge. This compression zone substantially increases dewatering efficiency.

Operating Principle The EIMCO® Gravity Belt Concentrator is based on the principle of solids-liquid separation enhanced by chemical conditioning of the solid particles by either agglomeration of flocculation. Three sequential unit operations are included: 1) conditioning of the slurry, 2) gravity drainage of the liquid from the solid particles, and 3) a mild pressure filtration zone to enhance cake solids discharge. Chemical Conditioning Conditioning chemicals are injected into the slurry through a four tangential inlet injection ring followed by a variable orifice venturi type mixer. The tangential inlet ring and variable orifice venturi provide even distribution and allow variable mixing intensity to ensure optimum utilization of conditioning chemicals. Efficient chemical utilization provides low conditioning costs per ton of dry solids. Conditioning and Distribution of the Slurry onto the Gravity Drainage Zone Following polymer/chemical injection, the slurry is conditioned in the feed

distribution box. Retention time of the slurry is approximately 30 seconds in a quiescent flow regime to allow further enhancement of the floc size and structure. The smooth weir overflow feed box evenly and uniformly distributes the slurry across the full width of the gravity drainage zone.

Gravity Dewatering Zone Two gravity dewatering options are available; 1(a single horizontal belt gravity zone, or 2) a drum concentrator followed by a horizontal belt gravity zone. The horizontal dewatering zone supports a filter belt media on transverse polyethylene slide strips. Rigid structural support of the polyethylene slide strips is provided by a stainless steel grid assembly. The polyethylene grid support allows filtrate to drain through the media into collection troughs. Furoughing devices in the gravity drainage zone plow deposited solid particles from the filter fabric, allowing liquid to pass through the media without the added resistance of deposited solids. Multiple rows of plows are provided, and each plow can be raised for cleaning and filter media replacement.

Filter Belt Cleaning Assembly After the filter cake is removed from the media, the filter belt passes through a totally enclosed spray wash assembly. High-pressure self-cleaning nozzles blast entrained solids from the filter media.

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Applications

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FLSmidth concentrators can be installed in new or existing plants to thicken sludge prior to digestion equipment. Influent to the plant and digester can be increased without having to enlarge the digesters. With digestion becoming a necessity, effective thickening ahead of digestion will become critical. FLSmidth concentrators are a cost- effective alternative to reduce the pathogen levels of sludge. FLSmidth concentrators can be installed in new or existing processing plants to economically dewater aggregate slimes. Where solids content of the cake needs to be dewatered to 55-60%, the EIMCO Concentrator has been proven to be an economical solution.

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Recovery of aggregate and sand from spent concrete truck washings.

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Waste sludge dewatering in Pulp and Paper mills and foundries.

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Metal filings removal from re-circulating cooling oil in Metal Finishing plants

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As a thickening stage in Metal Plating.

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Thickening sludges prior to ponding.

Typical Performance Results Feed WT% T.S.

Thickened Sludge WT% T.S.

Sludge Volume Reduction %

Pulp and Paper Fiber

1-5

7-15

70-95

Aggregate Concrete Slimes

8-20

30-55

50-60

Type of Sludge

Alternatives of FLSmidth’s EIMCO Concentrator DAF

Clarifier Thickener

Concentrator

Solids Capture

Good

Excellent

Excellent

Sensitivity to Septicity

Good

Poor

Excellent

Ease of Operation and Control

Poor

Excellent

Excellent

Capital Cost

Good

Excellent

Excellent

Energy Consumption

Poor

Fair

Excellent

Operating and Chemical Cost

Fair

Excellent

Fair

Maintenance

Fair

Good

Excellent

Land Required

Good

Fair

Excellent

Function

Alternatives to FLSmidth’s EIMCO Concentrator include Dissolved Air Flotation (DAF) and conventional clarifiers/thickeners. In many cases, neither of these alternatives can provide the economics of an FLSmidth concentrator, as shown in the following table.

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Features

Belt Drive All components of the drive assembly are sized to provide an AGMA rating of at least 1.25. Speed is controlled by a variable frequency controller mounted in the system control panel. The standard drive uses an electric motor and right angle gear reducer, which drives the discharge pulley of the unit through a chain and sprocket assembly. An optional drive consists of a hydraulic motor powered by the system hydraulic package. This option requires a slightly larger system hydraulic package but uses fewer components than the electrical drive. In applications requiring explosion proof motors, the hydraulic drive is less expensive.

Benefits: Standard Electric Drive • 10 to 1 variable speed range • Low maintenance costs • Fewer mechanical components • Proven reliability Bearings Self-aligning, spherical roller bearings with seals and end caps have an L10 rating, which exceeds 3,500,000 hours. Bearings are split-case pillow block design, bolted to the frame. An optional lubrication manifold can be supplied Benefits • Minimum maintenance • Long Life • Quick, easy replacement • Standard off-the-shelf bearing, anchor bolts, nuts and components

Frame The frame of FLSmidth’s EIMCO concentrator is constructed of 8 x 4 x 1/4 inch structural tubing with a structural moment of inertia of 44.5 inches, which provides an extremely rigid unit. Professionally certified finite element analysis and strain gauge tests demonstrate a safety factor of over 10 at 50 pli belt tension. Benefits • Accurate roll alignment for excellent bearing and filter belt life • No worry of frame damage during shipping, installation, operation, or maintenance • No concern with operational loads being transmitted to support structure and building Optional Hydraulic Drive Benefits: • 0-100% infinite variable speed range • Low installation cost • Low maintenance Costs • Proven reliability • Inherently safer

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Features (cont.)

Feedbox Heavy gauge stainless steel is used for the construction of the feedbox, which has a smooth overflow weir. The large volume, baffled bottom compartment provides a quiescent flow regime. Transition from the inlet pipe to the full width of the unit is smooth, while providing for sludge conditioning in the feedbox. Feedbox volume provides for .25 to .5 minutes retention time for sludge conditioning. Benefits • Excellent sludge distribution • Maximum utilization of gravity drainage • Retention time allows for sludge conditioning • No feedbox plugging problems • No moving components, less maintenance • Excellent corrosion resistance Plows Multiple rows of plows are provided. The plow assembly pivots to allow the plows to be rotated up out of the way during belt changing or to facilitate cleaning of the plows. Plow angle can easily by adjusted to maximize the furrowing action. Benefits • Maximize furrowing action and hydraulic throughput • Simplifies maintenance and cleaning • Eliminates potential damage of the filter belt from the plows

Gravity drainage Zone Effective filtration area is the key factor in maximizing hydraulic throughput capacity. More filtration area is provided by the 17-foot long EIMCO gravity drainage zone than by any other current design. The filter belt runs over polyethylene slide strips, mounted on stainless steel supports. Individual slide strips can be easily replaced and are adjustable to maintain a uniform level slide surface. Over 100 pounds per square foot of slurry can be carried on the stainless steel supports with only a 0.05 inch center span deflection. Benefits • High throughput • Maximum solids concentration • Rigid heavy-duty support structure and slide strips • Long wear life • Easy replacement • Low maintenance costs • Easy cleanup to reduce sludge build-up and odors

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Features (cont.)

Sludge Compression Zone A compression zone consisting of a plate assembly mounted ahead of the discharge roll compresses the sludge to express additional liquid prior to discharge. Benefits • Maximum sludge thickening • Simple adjustment • Increased effectiveness • Prevents upsets Proportional Belt Tracking Belts are maintained in proper alignment by a hydraulic sensor. An optional pneumatic system is available, which operates the same as the hydraulic design. When lateral belt movement occurs, a hydraulic cylinder is proportionally actuated to extend or retract one end of a pitch roll. Movement of the pitch roll changes the alignment of the roll, causing the belt to shift to the proper position. The servo-control valves provide continuous smooth, proportional control of the alignment roll, providing trouble-free belt alignment. All components are easily accessible for maintenance. A separate alarm system also senses extreme mis-alignment, which shuts down the concentrator. Benefits • Accurate alignment • Long belt life

Belt Tensioning The belt is adjustable by the hydraulic system to automatically maintain proper tension (a pneumatic system is available as an option). A hydraulic cylinder pivots on the rigid frame, which assure alignment on the tensioning roll. Controls are located on the frame for ease of operation. Benefits • Off shelf replacement parts • Easy access for maintenance • Long belt life • Low operating cost • Low maintenance

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Features (cont.)

Belt Washing Continuous washing of the belt is by high-pressure spray nozzles and stainless steel manifold. Overspray is contained inside the wash box by rubber seals. Self-cleaning shower spray nozzles with internal wire brushes are provided. By using filtrate from the gravity drain zone, wash water consumption can almost be eliminated. Benefits • Low operating costs • Maximum performance • Reduced maintenance • Maximum media life • Low water consumption Rotary Drum ConcentratorEfficient Dewatering of Dilute Slurries Prior to feeding the slurry to the gravity belt concentrator, a five compartment dewatering drum can be provided. Composed of five stainless steel, 4-foot diameter discs, the drum is supported by a center shaft with externally mounted bearings to prevent contamination from the slurry. Each disc has an opening offset from proceeding disc openings to permit thickening sludge to be retained prior to flowing into the next disc section. Rotational speed of the drum determines the amount of time the thickening sludge is retained in each section. Filter media attached to the drum by retaining clamps permit liquid to pass while retaining solids. The

thickened sludge is discharged form the fifth disc section to a chute and into the feed box of the lower gravity belt concentrator. On dilute slurries furloughing plows are ineffective because the slurry lacks sufficient body to furough. With the rotary dewatering drum, deposited solids are removed from the media by the rotating action. Free liquid passes through the media without resistance of the deposited solids. A rotary dewatering drum is more effective at initial thickening on dilute slurries than a furoughed horizontal drainage zone. A tighter filter media can be used on the drum to avoid solids loss that can occur with initial dewatering. A more open filter media can therefore be used on the gravity drainage dewatering belt for enhanced liquid discharge after the material has been pre-thickened in the rotary drum.

Benefits • Handles dilute feeds at maximum throughput • Optimizes initial dewater • Increases efficiency • 20% increase in hydraulic capacity per square foot of filtration area • Two independent dewatering zones provide additional freedom

Belt Thickener-Filter Press Package Slashes Dewatering Costs A new flow sheet for alum-treated water and wastewater sludge dewatering that combines an FLSmidth EIMCO® Gravity Belt thickener and Shriver® Filter Press can reduce the capital cost of dewatering hardware by as much as 50% with no reduction in final cake solids concentration. This opportunity exists because filter press filtration rates are very sensitive to feed slurry solids concentration. Because cake forms first along the media lining, each plate chambe, filtrate must be forced through a growing layer of existing cake. With dilute slurries, the production of a thick enough cake to ensure trouble-free discharge is a slow process. For example, the filtration rate of typical alum sludge with 2 wt% feed solids is 0.08-0.14 lbs./hr/ft.sq. This slow rate combined with heavy hydraulic loading translates into very large, heavy,

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Size

A

B

C

D

E

F

G

1.0 M

19’-6”

4’-8”

6’-2”

5’-0”

15’-6”

4’-4”

1’-4.5”

2.0 M

19’-6”

4’-8”

9’-6”

8’-4”

15’-6”

4’-4”

1’’-4.5”

3.0 M

19’-6”

4’-8”

12’-10”

11’-8”

15’-6”

4’-4”

1’-4.5”

complex and expensive filter presses. When feed solids are increased to the range of 6-8 wt% with a Gravity Belt Thickener, filtration rates increase by 300-400% allowing a proportional reduction in filter press sizing and expense. Further savings can be realized in the downsizing of feed tanks and pumps, and in the lighter structures required to support smaller equipment. An additional advantage of this arrangement is that the effects of polymer flocculants added to the belt thickener feed can be visually observed and immediately adjusted. This allows much more effective and economical chemical treatment than is possible when polymer is added to the filter press feed.

Operators of this small wastewater plant opted for pre-thickening industrial sludge on an FLSmidth EIMCO Gravity Belt Thickener prior to dewatering in a Shriver Filter Press. This resulted in a 50% reduction in filter press size, and $30,000 net capital savings on the equipment package. In plants with larger sludge flows, much greater savings may be expected.

Minerals Processing Technology Center FLSmidth Salt Lake City, Inc. 2850 S. Decker Lake Dr. Salt Lake City, UT 84119 Tel: +1 801 526 2103 E-mail: [email protected] Our brochure makes no offers, representations or warranties (express or implied), and information and data contained in this brochure are for general reference only and may change any time. Please contact us for specific information or data that may relate to your interest.

Rev. 06/2010 al-us

Performance, Sizes and Dimensions