11360 Sludge Dewatering System

TECHNICAL SPECIFICATIONS WASTEWATER TREATMENT PLANT UPGRADE AND EXPANSION PROJECT NEW BERLIN MUNICIPAL AUTHORITY

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SECTION 11360

SLUDGE DEWATERING SYSTEM

PART 1 GENERAL

1.01 DESCRIPTION

A. The Contractor shall furnish, install, and make ready to operate, a complete sludge dewatering system. The sludge dewatering system shall consist of one (1) belt filter press, two (2) digested sludge pumps, one (1) polymer feed system, one (1) wash water booster pump, one (1) hydraulic system or air compressor depending on the press furnished, and all necessary accessories in compliance with the following specifications and as shown on the Contract Drawings.

B. The hydraulic system (if so equipped) shall include pump, motor, valves, storage reservoir, and piping as necessary to provide a complete and operating system.

1.02 GENERAL REQUIREMENTS

A. All sludge dewatering equipment specified in this Section shall be supplied by the belt filter press manufacturer. The manufacturer shall provide a complete and operable system. The belt filter press and hydraulic system are specified herein.

B. The following equipment associated with the belt filter press is supplied by others. The digested sludge pumps are specified in Section 11301. The sludge grinder is specified in 11304. The polymer feed system is specified in Section 11347.

1.03 RELATED SECTIONS

A. The specifications listed below are an integral part of this equipment specification. The Contractor shall provide all of the listed sections to the belt filter press manufacturer.

1. Section 01300 - SUBMITTALS

2. Section 01400 - QUALITY CONTROL

3. Section 01600 - MATERIALS AND EQUIPMENT

4. Section 01640 - EQUIPMENT-GENERAL

5. Section 01660 - PLANT STARTUP AND INITIAL OPERATION

6. Section 09900 - FACILITIES PAINTING

7. Section 11080 - VALVES AND PIPING SPECIALTIES

8. Section 11300 - PUMPING EQUIPMENT-GENERAL

9. Section 11305 - DIGESTED SLUDGE FEED PUMPS

10. Section 11353 - POLYMER FEED SYSTEM

11. Section 11304 - SLUDGE GRINDER

12. Section 15170 - MOTORS

13. Section 17100 - MOTOR CONTROL CENTER

14. Section 17500 - DESCRIPTION OF OPERATION

B. All electrical equipment and wiring shall be in full conformance with Division 16, Electrical Specifications.


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1.04 PERFORMANCE REQUIREMENTS

A. General - The sludge dewatering system shall be capable of continuously dewatering an aerobically digested sludge (a combination of waste activated secondary and primary sludge). Sludge shall be fed onto the belt filter press from the aerobic digesters. The wastewater includes both municipal flows and landfill leachate.

B. The belt filter press shall also be capable of continuously dewatering scum from the clarifiers, which will be blended with the aerobically digested sludge. The maximum ratio of scum will be no greater than 1/3 scum to 2/3 digested sludge.

C. The press shall effectively accomplish solids-liquid separation to produce a dewatered sludge cake. Dewatered sludge shall be continuously discharged from the belt filter press to a conveyor. Filtrate and wash water drainage shall be collected and routed to a sump below the belt filter press.

D. Performance Criteria - The belt filter press shall be capable of operation under the following conditions:

1. Hydraulic Loading

- 100 gpm at 1.0 percent solids feed.

- 50 gpm at 2.0 percent solids feed.

2. Solids Loading - 200-500 lbs. dry solids/hour (combined).

3. Solids Capture - The minimum solids capture shall be 93 percent (%DS) under all conditions.

4. Sludge Output Solids Concentration - Sludge Dewatering Operation - Minimum 18 percent.

5. Sludge Conditioning - The maximum chemical usage to achieve the performance requirements shall be 10 pounds of polymer per ton of dry sludge solids (ODS). Polymer dosage rate based on pounds of active polymer.

E. Compliance with the performance requirements of this specification will not relieve the Contractor from his responsibilities to supply a belt filter press which has the structural, mechanical, and operational features specified herein.

1.05 SUBMITTALS

A. Shop Drawings - Shop drawings for all equipment supplied under this section shall be furnished in accordance with Section 01300 and Section 01660. A block diagram showing all electrical connections between system components (belt filter press, polymer system, diaphragm pump, booster pump, hydraulic system, and remote lights) shall be furnished with the shop drawings.

B. Performance Affidavit - A performance affidavit is required for all equipment specified in this section in accordance with Section 01660.

C. Operation and Maintenance Instructions - Complete operation and maintenance instructions shall be supplied in accordance with Section 01660.


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1.06 SPARE PARTS: The following spare parts which are identical to and interchangeable with the original parts shall be furnished in clearly identified containers.

A. Two (2) sets of seals for each inlet distributor, belt wash station, and wedge section;

B. One (1) set of hydraulic filters and seals for hydraulic system if used;

C. One (1) set of filter belts;

D. One (1) set of scraper blades;

E. One (1) bearing of each type and size;

F. Five (5) sets of fuses, light bulbs, limit switches and push buttons; and

G. One (1) complete set of gaskets for the wash water booster pump.

1.07 EXPERIENCE AND QUALIFICATION REQUIREMENTS

A. Due to the special importance of proper functioning of the equipment specified in this section to the satisfactory operation of the entire treatment system, the Contractor shall demonstrate in writing, to the satisfaction of the Owner at the time of the shop drawing submittal that the manufacturer has produced the specified type and size of equipment for sanitary wastewater service that has been in successful operation for a minimum period of five years prior to the bid date.

B. In the event the Contractor elects to install equipment whose manufacturer cannot comply with the above experience requirement, then the Contractor shall submit with shop drawings, appropriate bonds or deposits guaranteeing replacement of the equipment in event of failure for a period of three years after warranty. Such three year period shall start upon the termination of the Contractor’s basic warranty and guarantee obligations under the Contract.

C. During such three year period the Contractor shall repair, modify, or replace the equipment in a manner acceptable to the Owner, if in the opinion of the Owner, the operation of the equipment is unsatisfactory. Normal wear or malfunctions due to neglect or abuse will not be considered justifiable reasons for unsatisfactory operation. In the event the Owner determines the operation of the equipment to be unsatisfactory during this three year period and the Contractor fails to correct the deficiencies within six months from the time the Contractor is first notified in writing that such deficiencies exist, the Owner will make the necessary repair or replacement and deduct such costs from the aforementioned bonds or deposits of the Contractor.

PART 2 MATERIALS

2.01 MANUFACTURERS

A. The belt filter press manufacturer and model shall be the following or approved equal: Ashbrook-Simon-Hartley – Klampress 05.

B. The belt filter press shall be the models listed with the options and features specified herein.


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2.02 EQUIPMENT DESIGN

A. General

1. The belt filter press shall be a complete manufacturer-integrated high-efficiency system consisting of a fabricated structural frame, in-line static mixer, distribution chamber, gravity drainage section, wedge section, pressure section, belt wash stations, drainage system, belt tracking and tensioning system, complete with hydraulic system with associated booster pump.

2. Overall dimensions of the belt filter press including frame, rolls, drives, distribution chambers, valves, flanges, and all equipment and appurtenances attached to belt press frame shall not exceed 15’-0” long by 5-6” wide by 7’ high.

3. No disassembled component, excluding the belt filter frame, shall weigh more than 1,000 pounds. Lifting lugs shall be provided as necessary to afford convenient access to maintenance points throughout the belt filter. All wiring on the press shall be contained in PVC-coated galvanized steel conduit, fittings and enclosures.

B. Delivery, Storage, Handling: All equipment and components shall be furnished as complete assemblies with all internal wiring, piping, valving, and control devices. Items shall be delivered as complete assemblies except where partial disassembly is required by transportation regulations or for protection of components. Dewatering belts shall be shipped separately in suitable containers to protect them from accidental damage.

C. Materials

1. All components of the belt filter press shall be engineered for long, continuous, and uninterrupted service. Provisions shall be made for easy lubrication, adjustment, or replacement of all parts.

2. All structural steel shall conform to the ASTM Standard Specifications for Structural Steel, Designation A36-84a. All iron castings shall conform to the ASTM Standard Specification for Gray Iron Castings, Designation A48-76. All welding shall be in accordance with the latest applicable codes of the American Welding Society.

3. All materials in contact with polyelectrolyte or sludge shall be of stainless steel. All fasteners, pins, and anchor bolts shall be Type 316 stainless steel. All other stainless steel materials shall be Type 304. Except as otherwise specified, steel plates and shapes shall have a minimum thickness of 1/4-inch and bolts a minimum diameter of 1/2-inch.

D. Design Load Definition: The design load mentioned throughout this specification shall be based on the summation of all forces applied to the particular belt filter press component under discussion. These forces shall include, but not be limited to, roller weight, belt tension and shear forces, and friction forces. The design load shall occur under maximum loading conditions at the maximum belt speed. Load calculations shall be submitted to the Engineer upon request.


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E. Structural Frame

1. The belt filter press frame shall be made of structural steel “I” beam or channel members. Frame members shall be welded or bolted together to form an integral unit. Frame steel shall conform with ASTM Standard Specification for Structural Steel, A36/A36M-77. The frame shall be rigid and adequately braced to prevent deflection and vibration.

2. All frame steel shall have a minimum thickness of 0.375 inches. The maximum loading on any frame member shall be less than one-fifth of the yield strength of the steel. The frame shall provide support for press bearings and insure absolute plane parallelism of all rolling elements.

3. The frame shall be designed to be installed on a concrete foundation. The frame shall be secured to the foundation with anchor bolts. Frame construction shall allow for easy access and visual contact with all internal components of the belt filter press.

F. In-Line Static Mixer

1. The belt filter press shall be supplied with an in-line static mixer to blend the sludge with polymer. The static mixer shall be located on the sludge feed line leading into the belt press. The static mixer shall consist of a polymer injection ring, Venturi, mixing valve, polymer injection manifold complete with tubing and fittings for distributing polymer to the injection points on the ring, and transition pieces for connection to the sludge feed line. The injection ring shall include four injectors arranged tangentially around the sludge feed line. The mixing valve shall consist of an internal flap connected to an external adjustable, weighted arm or a pneumatically controlled pinch valve with panel mounted controller. The arm setting shall determine the amount of flow area through the mixer Venturi.

2. The sludge feed line and polymer feed line into the static mixer shall be provided with shut-off valves.

3. A minimum of three alternate points for polymer injection shall be provided.

G. Distribution Chamber

1. The belt filter press shall contain an inlet distribution chamber. The chamber shall have sufficient capacity for all sludge conditioning to be completed before any sludge is fed onto the belt filter press. From the distribution chamber, sludge shall be evenly distributed across the gravity drainage section of the press. The distribution chamber shall be made of AISI Type 304 stainless steel.

2. The distribution chamber shall have a drainage valve similar to the type used to shut-off the sludge and polymer feed lines. Minimum valve diameter shall be two inches.

H. Gravity Drainage Section

1. The belt filter press shall have a gravity drainage section with a minimum effective area 45 square feet. Belt speed and tension through the gravity drainage section shall be adjustable (see Motors and Drives). Rotary drums for gravity drainage are not acceptable.


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2. The filter belt in the gravity drainage section shall be supported by a system of bars across the belt width. The bars shall be spaced at a minimum of 2.5-inches apart along the entire length of the gravity drainage section. The bars shall be made of HDMW Polyethylene. The bars shall be supported by a stainless steel frame or grid plate.

3. The belt filter press shall have a minimum of six rows of plows in the gravity drainage section for directing sludge flow onto the filter belt. The vertical and horizontal position of each plow shall be individually adjustable. Each row shall include a lifting handle capable of lifting the row of plows out of the sludge flow at one time. The plows shall be made of HDMW Polyethylene. All plow mounting and lifting handle equipment shall be made of hot dip galvanized or stainless steel.

4. The gravity drainage section shall include stainless steel side barriers with replaceable rubber or fabric seals to contain sludge flow on the filter belt.

I. Wedge Section

1. The belt filter press shall have a separate and distinct wedge section with a minimum effective area of 8 square feet. The wedge section shall accept thickened sludge from the gravity drainage section and direct it into the -pressure section. the wedge zone shall be provided in order to gently apply and gradually increase the pressure on the thickened sludge. The wedge zone is formed by the convergence of both filter belts coming oft of their respective tensioning rollers and gradually forming a cloth/cake sandwich prior to contacting the perforated roll in the pressure section. The pressure shall be gradually increased by a grid of UHMW supports beneath the bottom cloth. The effective dewatering area of the wedge zone shall be a minimum 5.66 sq.ft. The wedge section shall accept thickened sludge from the gravity drainage section and direct it into the pressure section.

2. The wedge section shall consist of a belt support system, side barriers, a convergence roller, and a filtrate collection pan. The belt support system, side barriers, and filtrate collection shall be similar in design to those used in the gravity drainage section.

3. As sludge moves through the wedge section it shall be compressed by the pressure section belts. The closure angle of the wedge section shall be determined by the horizontal position of the convergence roller.

J. Pressure Section

1. The belt filter press shall have a separate and distinct pressure section with a minimum effective area of 24 square feet. Sludge dewatering in the pressure section shall be the result of shear and compression forces acting on internal sludge water. The pressure section shall consist of a minimum of five rollers and two belts.

2. Sludge in the pressure section shall travel in an “S” shaped pattern, over and under the rollers. As the sludge moves through the rollers, it shall alternately be compressed and then allowed to expand.


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3. Belt speed and tension through the pressure section shall be adjustable (see Motors and Drives). A low volume, high pressure, self-contained wash station shall be included after the pressure section for each of the filter belts. Rollers in the pressure section shall be accessible from outside of the press frame for repair and maintenance purposes.

K. Discharge Blades: Discharge blades shall be provided to separate the dewatered sludge from the discharge rollers. Blades shall be adjustable and beveled at each end. Each discharge blade shall be easily removable for replacement when required and fully accessible. Discharge blades shall be of high density polyethylene or polypropylene.

L. Belt Tracking System

1. Each belt shall be provided with a manual tracking system. The tracking system shall provide adjustment of belt position on press rollers in order to maintain correct belt alignment. Each belt tracking system shall include a sensing arm and adjustable steering roller.

2. The sensing arm of the tracking system shall be in continuous contact with the belt edge. When a belt becomes misaligned, the sensing arm shall send a signal to a light. The adjustment wheel shall cause the steering roller to change position until the belt is correctly aligned.

3. All belt tracking system components shall operate with smooth and slow motions resulting in a minimum of belt travel from side to side. Limit switches shall be included in the belt tracking systems to protect against gross belt misalignment. Each tracking system shall contain two switches. One limit switch shall be placed on each side of a belt. The limit switches shall cause automatic and instantaneous shutdown of belt drives and sound an alarm upon tracking system failure.

M. Belt Tensioning Systems

1. Each belt shall be provided with an automatic belt tensioning system. The belt tensioning system shall be either hydraulically or pneumatically driven. The system design shall be such that the dewatering pressure on the sludge is directly proportional to belt tension. Belt tension adjustment shall result in an immediate change in dewatering pressure.

2. Each belt tensioning system shall be furnished with a control station for adjustment of belt tension. Belt tension shall be adjustable from 0 to 50 pounds per linear inch.

3. Each control station shall have a belt tension indicator meter. The meter shall correlate belt tension with hydraulic or pneumatic pressure. The meter shall be calibrated in units of pounds of belt tension per linear inch. Normal tension operating limits shall be indicated on the meter.

4. Each belt shall have one tension roller. The roller shall be positioned by hydraulic or pneumatic cylinders to maintain the desired belt tension. Belt tension shall be maintained at a constant level regardless of process changes.

5. The belt tensioning system shall include sensing devices that shall cause automatic and instantaneous shutdown of belt drives and sound an alarm in the case of belt tensioning system failure.


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N. Belts

1. The belt filter press belts shall be made of wear-resistant monofilament polyester. Belt ends shall be joined with an ANSI 316 stainless steel clipper seam. A polyurethane or plastic coating shall be applied on belt seam to provide a smooth seam surface. Belt edges shall be heat sealed and bonded to protect against belt wear.

2. All belts shall have drive, tensioning, and tracking rollers. The minimum effective width of all belts shall be 0.6 meter. Minimum belt life shall be 2000 hours of continuous operation at design conditions. The minimum tensile strength of all belts and seams shall be five times the maximum dynamic tension to which a belt shall be exposed. The belt seam shall be designed to fail before belt material when under tension.

3. Belt porosity and mesh design shall allow for optimum sludge dewatering and to prevent belt blinding. Pressure belts shall be of low porosity, designed for compression dewatering.

4. Belt selection shall be based on the manufacturer’s experience. All belts shall have been used successfully by the manufacturer on similar sludges using similar polyelectrolyte conditioning chemicals. The manufacturer shall submit evidence of belt suitability with the Shop Drawings.

5. All belts shall be designed for ease of replacement with a minimum of press downtime. Belt replacement shall not require disassembly of the filter press.

O. Rollers

1. All rollers shall be made of carbon steel or stainless steel. Rollers shall have either double plate stub end or through shafts. Stub end shafts shall be welded to the roller end plates. The minimum wall thickness of a roller body shall be 1/2-inch. The minimum end plate thickness shall be 1/2-inch.

2. Deflection over the full length of a roller shall not exceed 0.05 inches when the roller is under maximum design load of 50 ph. Rollers shall be designed to handle stresses in excess of seven times the endurance limit of roller materials and welded connections when subject to belt tension of 50 ph.

3. All rollers shall be designed for a maximum deflection of less than 0.05”at mid span under maximum loading conditions. Maximum loading shall be defined as the sum of the belt tension load at 50 pli; friction loads; equipment and sludge loads; any loads induced by the elasticity of the belts; and any loads induced by the torque of the drive. Rollers shall be designed to handle stresses in excess of five times the endurance limit of roller materials and welded connections when subject to belt tension of 50.

4. All calculations for roller deflection and bearing load shall be calculated using a belt tension of 50 psi.

5. Carbon steel rollers shall be covered with vulcanized Buna-N-rubber or heat-setting, thermoplastic nylon for corrosion protection. The minimum Buna-N-rubber coating thickness shall be 1/4-inch. The minimum nylon coating shall be 30 mil. All coatings shall have a minimum Shore “A” hardness rating of between 55 and 65.


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P. Bearings

1. All rollers shall be equipped with industrial, continuous duty, spherical double row roller bearings. All bearings shall be self-aligning and mounted in cast iron, split case, pillow block housings with a cast water trough.

2. The design load on a bearing shall not exceed 25 percent of the bearing’s ultimate rating. All bearings shall have a minimum L-l0 life of 100,000 hours based on ANSI/AFEMA STD 11-1978. Maximum roller shaft speed and design loading shall be used in the calculation of the minimum L-l0 life.

3. All bearings shall be designed for use in a “wet” environment. Bearings shall incorporate lip contact seals, labyrinth seals, and other devices to prevent dirt and water intrusion into a bearing. All bearings shall be provided with a water “flinger.”

4. All rollers shall be provided with one fixed and one floating bearing to allow for shaft expansion and contraction. All bearings shall be outboard (externally mounted) bearings and shall be greaseable while the filter press is in full operation. All grease fittings shall be extended to the outside edge of the frame.

5. All bearing housings shall be mounted on the press frame with a minimum of two bolts. All roller bearings and housings shall be U.S. manufactured in the FMC Corporation, Link Belt Division, Indianapolis, IN; SKF Industries, Philadelphia, PA; Rexnord, Downer’s Grove, IL; or equal.

Q. Belt Wash System

1. A belt wash system shall be furnished within each belt loop. The belt wash station shall consist of a minimum of one spray pipe fitted with non-clog nozzles. Nozzle spacing and spray pattern shall be such that the sprays from adjacent nozzles overlap one another at the belt surface. The spray pipe and nozzles shall be of stainless steel construction. Individual nozzles shall be removable.

2. The wash water supply pipe and nozzle assembly shall be housed in a manner that limits the spray pattern to within the wash station. The housing and nozzle assembly shall be readily removable. The housing shall be fabricated from stainless steel and include replaceable seals above and below the belt at both the exit and entrance to prevent the escape of spray mist.

3. The belt wash station shall be positioned such that the washing is performed after the cake has been discharged from the belt. The belt wash station shall extend over the full width of the filter belt by a minimum of two inches. No blinding shall occur when the belt is cleaned at the wash station. Each belt wash station shall be furnished with a rotometer and manual globe valve for throttling. The rotometer shall be furnished with shutoff valve and bypass piping to isolate the wash station from the general washwater system.


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4. The belt wash system shall use non-potable water and be designed to operate at a maximum flow of 15 gpm. The belt wash system shall include electrically-operated solenoid valves to control wash water flow to the filter press. The solenoid valves shall be supplied with a manual override. The manual valves, rotometers, and solenoid valves shall be mounted on the belt filter frame. The belt filter press shall be provided with a separate discharge connection and piping for wash water and filtrate discharge. Solenoid valve controls shall be part of the filter press control panel.

5. The spray headers shall be piped to a common washwater inlet connection on the press. A NEMA 4X solenoid valve and NEMA 4X pressure switch shall be provided in the water inlet manifold, both for on-off control and to provide an alarm signal in the event of low washwater pressure.

6. The belt wash station shall be furnished with an external handwheel that, when rotated, shall cause the brush bristles to enter each spray nozzle and clean-out any solid particles which have accumulated.

7. Belt wash station shall be the type manufactured by Appleton Manufacturing, Sprayco, or equal. All wash station components shall be made of AISI Type 304 stainless steel, brass or bronze.

R. Wash Water Booster Pump

1. One in-line wash water booster pump shall be provided by the belt filter press manufacturer.

2. The booster pump shall be rated at sufficient capacity and discharge head to meet the wash water requirements of the belt filter press.

3. The suction line of the booster pump shall be connected to the utility water system which will operate at a minimum water pressure of 50 psig.

4. The equipment supplier shall verify operating pressures of water system with Contractor.

5. The booster pump motor shall be sized to meet the requirements specified herein and shall be suitable for 480 volt, 3 phase, 60 Hertz power.

6. The booster pump shall meet the requirements of Section 11300.

S. Drainage Pans: Drainage pans shall be supplied to contain all filtrate and wash water within the belt filter press and to prevent rewetting of downstream cake. Filtrate and wash water pans shall be constructed of AISI Type 304 stainless steel or 1/4-inch thick FRP and shall be piped separately to the drainage basin. All drainage piping shall be Schedule 40 PVC, adequately sized for the intended service and rigidly attached to the press frame. Drain connections shall be self venting to prevent overflow. Flushing connections or similar provisions shall be provided for easy access during cleaning. Drainage pans shall be located such that the moving belts do not come into contact with the pans under any conditions.

T. Anchor Bolts: All anchor bolts and nuts and other fasteners furnished for the connection of the equipment, and other miscellaneous items to the concrete structure of concrete base pads shall be of AISI Type 316 stainless steel furnished by the equipment manufacturer, and shall be of ample size and strength for the purpose intended.


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U. Hydraulic System (if so equipped)

1. The belt press shall have a separate hydraulic system. The system shall include an electric motor, pump, reservoir, filter, directional and flow control valves, pressure gauges, and all necessary piping and fittings. The hydraulic system shall operate on 460 volt, 60 Hertz, 3-phase power supplied from the belt filter press control panel. The electric motor shall be 3 HP maximum.

2. All piping shall lead to a manifold located on the hydraulic pump. A low hydraulic pressure switch shall shut down the belt press and activate an alarm on the belt press control panel upon loss of hydraulic pressure.

3. The manufacturer shall provide all equipment necessary to make the hydraulic system complete and operable. All hydraulic lines shall be rigidly supported on the structural frame and be properly sized for the intended use with adequate factors of safety for the pressure rating. All hydraulic piping shall terminate at a single inlet connection mounted on the press frame.

2.03 ACCESSORIES

A. Pressure Gauges - Pressure gauges shall be furnished and installed on the washwater booster pump and on the hydraulic unit (if supplied), in accordance with Specification Section 11300. Gauges shall be installed with a manufacturer’s standard pulsation dampener and shutoff valve. The ranges of the gauges shall be suitable for any range of pressure that can occur during operation.

B. Solenoid Valves - Solenoid valves shall be furnished and installed on the washwater supply in accordance with Specification Section 11080. Valves shall be suitable for operation on 120-volt, single phase, 60 Hertz current, and designed to open when energized.

C. Connections - All connections 3 inches or greater shall have flanged ends faced and drilled in accordance with 125-lb. ANSI standards. All connections less than 3 inches shall be threaded in accordance with NPT Standards.

2.04 MOTORS AND DRIVES

A. All belt drives shall be one of the following drive types:

1. Hydraulic drive motors with hydraulic power pack.

2. Alternating current (A.C.) motor with a variable frequency drive (VFD).

B. Each press drive shall be adequately sized for its intended purpose under maximum conditions. Maximum conditions shall be based on the maximum belt speed and maximum sludge loading of the press and the summation of all forces applied to the press.

C. A.C. Motors / VFDs

1. The belt press shall have an A.C. gear motor with a variable frequency drive. The gear motor and VFD controls shall work on 460 volt, 60 Hertz, 3-phase power. The gear motor shall be TEFC with a service factor of 1.15. The gear motor shall be NEMA B design with Class F insulation.


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2. VFD controls for the gear motor shall be mounted on the belt press control panel and provided by the belt press manufacturer. All A.C. motors, VFD controls, and other electrical equipment shall be in full compliance with division 16, Electrical Specifications.

2.05 CONTROLS

A. Controls will be provided by the Process Control System (PCS) supplier. Refer to Section 17500 - Description of Operation for a description of the controls.

B. An emergency trip cord which activates a switch when pulled shall be located on each side of the press. The switch shall be a maintained contact closure with reset. The control wiring shall be such that in the event the emergency trip cord is pulled, power to the belt filter press and appurtenant equipment can be reset only at the belt filter press control panel.

2.06 PAINTING

A. The frame shall be stainless steel or hot-dipped galvanized in accordance with ASTM Specification A123 to a thickness of 4 to 7 mils.

B. Shop preparation and shop and field coats of paint shall be applied in accordance with Specification Section 09900, and as specified herein.

2.07 STANDARDIZATION OF GREASE FITTINGS: All grease fittings shall be supplied in accordance with Specification Section 01660.

PART 3 EXECUTION

3.01 EQUIPMENT INSTALLATION: The equipment shall be installed by the Contractor in accordance with the instructions of the manufacturer and Specification Section 01400, and Section 01660, including furnishing oil and grease for initial operation.

3.02 FIELD TESTING AND INITIAL OPERATION A. Tests, trials, and initial operation shall be performed on the sludge dewatering

system in accordance with this specification and Specification Section 01660.

B. Contractor shall furnish all oil and grease for initial operation. The belt press manufacturer shall provide a minimum of two 20 gallon carboys of liquid polymer to perform all field tests and trials for the period of initial operation.

C. Preliminary Field Test - The following preliminary field test shall be conducted:

1. Verify that the belt filter press, hydraulic pump, and control panels are installed in accordance with the Contract Specifications and Drawings and with the manufacturer’s recommendations.

2. Verify that the belt filter press and hydraulic pump have been properly lubricated, aligned, and adjusted in accordance with the manufacturer’s instructions and are ready for operation.

D. Final Acceptance Test - The following final acceptance test shall be conducted:

1. Demonstrate that the hydraulic pump delivers the pressure needed for proper system operation.

2. Demonstrate that each belt drive operates properly through the entire specified belt speed range.


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3. Demonstrate that each belt tensioning mechanism will provide the specified range of belt tension.

4. Demonstrate that the belt filter press system will meet the specified performance requirements. The polymer feed system, sludge grinder, scum, and digested sludge feed pumps shall be fully installed and operational before this test is run.

5. Feed sludge for this test shall be from the existing Wastewater Treatment Plant. Contractor will transfer the sludge to the aerobic digester.

6. The dewatering test shall be run for a minimum of four hours. Sludge feed, filtrate, and cake discharge samples shall be taken at the start of the test and every 20 minutes thereafter (for a total of 7 samples at each sampling location) At no time during the test shall cake solids fall below the specified percent solids, solids capture, nor polymer usage exceed the specified pounds dry polymer per dry ton of sludge solids.

7. Demonstrate that all controls at the belt press control panel, the belt press, and hydraulic pump, or air compressor operate properly.

3.03 SERVICES OF MANUFACTURER’S REPRESENTATIVE: Provide manufacturer’s (or supplier’s) services according to Specification Section 01660.

3.04 GUARANTEE A. In addition to the general guarantee in Article 13 of the General Conditions, the

Contractor shall provide the Owner with a guarantee from the belt press manufacturer. This maintenance guarantee shall be in force for a period of three years from the date of initial startup of the belt filter press.

B. This shall guarantee the mechanical performance of the frame, frame coatings, rollers, roller coatings, bearing and bearing coatings. It shall further guarantee repair (parts and labor) and correction or replacement of any defect in these components which may become evident at any time during the five-year period, at no cost to the Owner. This guarantee specifically excludes normal wear items such as belts and seals.

END OF SECTION

11360 Sludge Dewatering System

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