Rake Bottom – Specifications

INCLINED PLATE CLARIFIER WITH SLUDGE THICKENING BOTTOM PART 1 – GENERAL

1.1 Scope: The work covered in this section includes furnishing all labor, material, equipment and incidents to install complete and ready for operation, an inclined plate clarification device as shown on drawings and as specified herein.

1.2 APPLICABLE PUBLICATIONS: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

American National Standards Institute (ANSI) Publication:

B16.1 Cast Iron Pipe Flanges and Flanged Fittings, Class 25, 125, 250 and 800

American Society for Testing and Materials (ASTM) Publications:

A-36 Structural Steel
A-53 Pipe, Steel, Black and Hot Dipped, Zinc Coated, Welded Seamless
A283 Low and Intermediate Steel Plate of Structural Quality

American Welding Society (AWS) Publications:

D1.1-84 Structural Welding Code, Steel
A5.1 Mild Steel Arc-Welding Electrodes

Standard Welding Terms and Definitions

Standard Welding Symbols

Steel Structures Painting Council (SSPC) Publication:

SSPC-SP-10 Near White Blast Cleaning

American Institute of Steel Construction (AISC) Steel Construction Manual, 8th Edition

1.3 SUBMITTALS:

1.3.1 Contracting officer will review and approve all submittals.

1.3.2. Submit the following before fabrication

1.3.2.1 Shop Drawings: Shop drawings for clarification and accessory equipment including principle dimensions and location of fittings. Data shall include weight and distribution of weight with the unit empty and filled with water.

1.3.2.2 Test results, signed by the manufacturer, which indicate the clarifier is capable of handling specified effluent concentration, pH, fluid temperature and concentration of suspended solids. Tests on this model shall have been done within the last 3 years.

1.3.2.3 Provide calculations of clarifier loading rate at the design flow rate.

1.3.3 Submit the following after fabrication:

1.3.3.1 Verification:

  1. Written verification on the fabricator’s letterhead that surface preparation and coating application were performed in accordance with the specification and coating specification and system manufacturer’s printed recommendations;
  2. That the unit was hydraulically leak tested for a period of at least 4 hours before further surface preparation and coating;
  3. That the surface preparation and coating process was performed at a facility owned and operated by the manufacturer;

1.4 MANUFACTURER’S SERVICE REPRESENTATIVE’S REPORT AND CERTIFICATE: Submit service representative’s complete signed report of results of the inspection, operation, adjustment, and tests. Report shall include detailed descriptions of points inspected, tests and adjustments made, quantitative results obtained if such are specified, and suggestions for precautions to be taken to ensure proper maintenance. Include the manufacturer’s certificate that equipment conforms to specified requirements and is ready for permanent operation and that nothing in installation will render manufacturer’s warranty null and void.

1.5 DELIVERY, STORAGE, AND HANDLING MATERIALS:

1.5.1 Delivery and Storage: Inspect materials delivered to site for damage; unload and store with minimum handling. Store materials on site in enclosures or under protective coverings. Protect materials not suitable for outdoor storage to prevent damage during periods of inclement weather, including subfreezing temperatures, precipitation, and high winds. Store materials susceptible to deterioration by direct sunlight under cover and avoid damage due to high temperatures. Do not store materials on ground. Store and protect materials according to manufacturer recommendations.

1.5.2 Handling: Handle inclined plate clarifier in such a manner as to ensure delivery to final location in sound, undamaged condition. Take special care not to damage interior and exterior surfaces of the inclined plate clarifier. Make satisfactory repairs to damaged material(s) at no cost. Carry and do not drag materials. Handle inclined plate clarifier according to manufacturers information.

1.6 QUALITY ASSURANCE:

1.6.1 Inspection: Examine each component of clarifier for compliance with requirements specified. Redesign or modification of equipment to comply with specified requirements, or necessary redesign or modification following failure to meet specified requirements, shall receive particular attention for adequacy and suitability. This element of inspection shall encompass visual examinations and dimensional measurements. Noncompliance with specified requirements, or presence of one or more defects preventing or lessening maximum efficiency of clarifier operation, shall constitute cause for rejection.

1.7 WELDER QUALIFICATIONS:

1.7.1 Welders shall be previously qualified by passing the tests prescribed in the AWS Standard Qualification Procedure, or by passing such other tests as the Engineer may accept.

1.7.2 Welders shall have been tested within the past twenty four months and their qualifications shall be considered as remaining in effect unless the welder is not engaged in a given process of welding for a period exceeding six months.

PART 2 – INCLINED PLATE CLARIFIER DESIGN CRITERIA AND MANUFACTURING SPECIFICATIONS

2.1 INCLINED PLATE CLARIFIER – APPLICATIONS & PERFORMANCE

2.1.1 Applications: The inclined plate clarifier shall be used to separate entrained suspended solids from a wastewater stream having a flow rate of * gallons per minute. Water entering the flash mix section has previously been conditioned to destabilize micro colloidal suspended solids. Two additional compartmental tanks with mixers are provided to flash mix an activated polyelectrolyte with the conditioned wastewater and then slowly flocculate the suspended solids into easily settleable masses.


*COMPLETE BLANKS FROM ATTACHED CHART

The flocculated suspended solids precipitate from entrainment as the hydraulic flows moves through the clarifier’s inclined plates, collect and slide down the incline, falling into the clarifier sludge hopper. The settled sludges collect on the bottom of the sludge hopper and are mechanically raked to the center of the tank and discharged on an as needed basis to a filter press or sludge thickener via air diaphragm pumps. The clarified water gravity flows from the top of the clarifier to a sand filter or discharge.

2.1.2 Performance: The clarifier shall remove the at least 98% of the destabilized and conditioned micro colloidal suspended solids from * gallons per minute flow and be designed with a flat bottom center outlet to thicken the collected solids to 3-5 percent by weight.

2.2 Inclined Plate Clarifier – Manufacturing specification

2.2.1 The manufacturer of the inclined plate clarifier and related components shall have been manufacturing clarifiers of the following specified design for at least five years. The clarifier and components shall be fabricated and assembled at the steel fabrication facility owned and operated by the manufacturer. Sandblasting and coating operations shall also be performed at the manufacturers’ facility. The manufacturer shall maintain a quality control staff to perform quality assurance checks during fabrication and assembly.

2.2.2 Inclined plates shall be set at a minimum of 60 degrees above the horizontal plane.

2.2.3 The maximum flow rate through the inclined plate clarifier shall not exceed 0.25 gallons per minute per square foot of horizontal projected area. (Horizontal projected area of an inclined plate set at 60° is 50% of the total surface are).

2.2.4 Forced uniform flow throughout the inclined plate section shall be created to assure that each plate received an equal amount of flow and that the flow is distributed over the entire effective width of each plate without short circuiting by the incorporation of an adjustable stainless steel V-Notch overflow panel located at least 6″ above and on both sides of the plate sections. The manufacturer shall supply data of a installation with at least five years operating experience that demonstrates this method of flow equalization. Center mounted effluent collection structures do not provide uniform flow across the plate section and are not acceptable.

2.2.5 To ensure full utilization of all plate areas and to prevent the shearing of floc particles, Velocities through the unit shall be kept below 1 FPS. Flow velocity calculation shall be submitted for feed ducts, feed bay and plate separators.

2.2.6 The clarifier shall be provided with minimum 4 inch freeboard at design flow rate.

2.2.7 The minimum plate spacing shall be 2 inches. Plates shall be fabricated of fiber reinforced plastic. The plates shall be supported by dividers constructed of stainless steel, Teflon or molded plastic inserts and shall be individually removable.

2.2.8 The settling plates shall have a length to width ratio of * to 1. The plates shall be a minimum of 0.09 inches thick FRP. The plates shall have a resin rich surface to prevent fiber show. The plates shall be produced by contact molding or machine extrusion, “hand or spray lay-up fabrication” will not be acceptable.

2.2.9 The plates shall be 24″ wide supported on the sides and center, such that unsupported distances shall not exceed 12″. Settling plates wider than 24″ shall be supported on 12″ center or provide documentation and test results that the plates will withstand a load of 100% filled with sludge, specific gravity 1.4 or above, with all water drained from the clarifier, without plate collapsing. Manufacturer shall provide a minimum of five installation references with at least five years service without failure.

2.2.10 Gasket materials utilized in the plate construction shall be Viton or Teflon. All assembly clips shall be constructed of Teflon.

2.2.11 Inlet and outlet shall be flanged connections drilled to ANSI B16.1.

2.3 MANUFACTURING SPECIFICATIONS – INTEGRAL SLUDGE HOPPER

2.3.1 The inclined plate clarifier shall have an integral sludge hopper located below the plate zone. The sludge compartment shall be supplied with a flat bottom and have a top driven motorized rake to break up and direct sludge to a central discharge compartment.

2.3.2 The sludge hopper shall have three (3) sludge samples 3/4″ NPT nipples and a 20 inch manway.


*COMPLETE BLANKS FROM ATTACHED CHART

2.3.3 The rake shall be a cantilevered design with the motorized drive, supported above the solution to eliminate submerged rotating seals. The rake drive shaft shall have a bottom mounted steady rest support. All seals and bearings shall be above the water surface. The high efficiency cyclical gear motor shall have at least * inch pounds of torque and be driven by a 440V, 3 phase, TEFC motor. The horsepower shall not exceed * .

2.3.4 The sludge hopper shall have a volume of at least * gallons.

2.3.5 Two (2) zinc anodes mounted to 3/4″ male pipe plugs shall be mounted in the hopper above the rake for galvanic protection.

2.4 Manufacturing Specifications – Flash Mix and Flocculate Section

2.4.1 Rapid mix tank shall have a minimum detention time of 30 seconds at design flow rate.

2.4.2 Rapid mixer to be a single speed (maximum output speed 120 rpm) mixer comprised of vertical shafted mixer with at least 75% length of the mix chamber height, gear reducer and motor. The mixer shall have a rigidly mounted bottom steady rest support. The gear motor shall provide at least 300 inch pounds of torque and be driven by a 440V, 3 phase TEFC motor. All seals and bearings shall be above the water surface.

2.4.3 Flocculating tank shall have a minimum detention time of 2 minutes at design flow rate with a motorized vertical shaft mixer, variable speed, that supplies low turbulent motion to build the floc.

2.4.4 Flocculate mixer shall be a fixed speed with a maximum speed not to exceed 40 rpm’s comprised of mixer paddles, variable gear reducer and TEFC motor. The gear motor shall provide at least 300 inch pound of torque at maximum speed and shall be driven by a 440V, 3 phase motor. The mixer shaft shall have a rigidly mounted bottom steady rest support. All seals and bearings shall be above the water surface.

2.4.5 Rapid mix tank and flocculating tank to have a minimum 4 inch freeboard at the design flow rate.

2.4.6 Rapid mix tank shall have a chemical injection pipe connection for injection of polymer directly below flash mixer.


*COMPLETE BLANKS FROM ATTACHED CHART

2.4.7 The rapid mix and flocculate tank shall be equipped with at least 3 integral anti-vortexing baffles.

2.5 MANUFACTURING SPECIFICATIONS – PLATFORM

2.5.1 A platform shall be included for the inspection of the rapid mix, flocculating and clarifier compartment.

2.5.2 Access to the platform shall be provided by ladder. A cage shall be included if the ladder exceeds 20 feet.

2.5.3 Platform floor grating shall be coated for corrosion resistance.

2.5.4 The platform shall have a handrail to protect personnel. The opening between the rails shall be in compliance with OSHA and UBC standards and shall not exceed 12 inches.

2.6 STRUCTURAL

2.6.1 All structural and tank steel stresses shall be within the allowable limits shown in the Steel Construction Manual of the American Institute of Steel Construction, Eighth Edition.

2.6.2 The unit to be structurally designed for installation in Seismic Zone * in accordance with 1985 Uniform Building Code.

2.6.3 Clarifier shall be fabricated from ASTM A-36 steel.

2.6.4 All exterior welds shall be continuous seal weld or the weld must be caulked before surface coating.

2.7 ELECTRICAL:

2.7.1 Rapid mixer, flocculate drive and sludge drive unit shall have 440V, 60 Hz, 3 phase TEFC or TENV motors, maximum 1 HP.

2.8 TESTING:

2.8.1 All seal welds shall be visually checked for continuity, pinholes, and voids.

2.8.2 The entire unit shall be shop-hydrostatically tested. Documentation of hydrostatic test shall be provided.


*COMPLETE BLANKS FROM ATTACHED CHART

2.9 SURFACE PREPARATION AND COATING

2.9.1 Surface Preparation: The steel surfaces must be dry and clean in accordance with the following requirements. Remove all grease, oils and contaminants as outlined in SSPC SP1. Remove all weld splatter and grind burrs on cut edges and rough welds smooth. Blast clean all surfaces after fabrication in accordance with SSPC SP10 with profile depth of 1.5-2.0 mils. Apply first primer before any rust bloom forms.

2.9.2 Caulking: All exterior non-seal welding joints shall be filled with rubber caulking before painting.

2.9.3 Exterior Surfaces:

Shop First Coat: Apply one coat average dry film thickness of two mils minimum, of a high-build catalyzed epoxy. Apply to all steel surfaces except the areas within 2 inches adjacent to field welds and surfaces specified to be hot-dip galvanized. The paint shall be Hempel 4563U.

Shop Finish Coat: Apply one coat average dry film thickness of 1.0 mils minimum, of a polyurethane paint. Recoat at time interval recommended by the manufacturer, the final coat shall be Hempel 5595U.

Third Coat: Field touch-up of damaged and unpainted areas shall be the same as specified first and second coats at the same film thickness.

The total dry film thickness shall be a minimum of at least 4 mils.

2.9.4 Interior Surfaces:

Shop First Coat: Apply one coat average, dry film thickness of four mils, of an immersion grade high-build catalyzed epoxy. Apply to all steel surfaces except the areas within 2 inches adjacent to field welds and surfaces specified to be hot-dip galvanized. The paint shall be Hempel 15409.

Shop Finish Coat: Apply one coat average, dry film thickness of 4 mils, of an immersion grade high-build catalyzed epoxy. Recoat at time interval recommended by the manufacturer, the final coat shall be Hempel 15409.

Third Coat: Field touch-up of damaged and unpainted areas shall be the same as specified first and second coats at the same film thickness. (Liquid Contact).

The dry film thickness shall be an average of 6 mils.

PART 3 – DELIVERY, STORAGE AND HANDLING MATERIALS

3.1 Delivery and Storage: Inspect materials delivered to site for damage; unload and store with minimum handling. Store materials on-site in enclosures or under protective coverings. Protect materials not suitable for outdoor storage to prevent damage during periods of inclement weather, including subfreezing temperatures, precipitation and high winds. Store material susceptible to deterioration by direct sunlight under cover and avoid damage due to high temperatures. Do not store materials directly on ground. If special precautions are required, prominently and legibly stencil instruction for such precautions on outside of equipment or its crating. Store and protect materials according to manufacturers recommendations.

3.2 Handling: Handle sludge thickener tank in such a manner as to ensure delivery to final location in sound, undamaged condition. Take special care not to damage interior and exterior surfaces of sludge thickener tank and associated supports and pipe coatings or linings. Make satisfactory repairs to damaged material(s) at no cost. Carry and do not drag materials. Handle sludge thickener tank according to manufacturers information.

PART 4 – EXECUTION

4.1 Installation: Inclined plate clarifier tanks to be installed as indicated and as recommended by the manufacturer. Equipment delivered to the site in advance of installation to be stored per the manufacturer’s requirements. Make all connections as required to make inclined plate clarifier fully operational. Do not weld tank surfaces, interior or exterior, it will permanently damage the interior lining. If welding has inadvertently occurred, the interior surface affected shall be abrasively ground to white metal and two coats of Hempel 15409 applied, with air dry between coatings.

4.2 Field Inspection Services: Examine each component of inclined plate clarifier for compliance with requirements specified. Redesign or modification of equipment to comply with specified requirements, or necessary redesign or modification following failure to meet specified requirements, shall receive particular attention for adequacy and suitability. This element of inspection shall encompass visual examinations and dimensional measurements. Noncompliance with specified requirements, or presence of one or more defects preventing or lessening maximum efficiency of inclined plate clarifier operation, shall constitute cause for rejection.

4.3 Start-Up Testing: Manufacturer’s field representative shall inspect and test unit and certify that the installation has been performed in accordance with manufacturer’s recommendations and that the system is ready for operation by others. Inspection shall consider, but not be limited to, the following:

  1. Soundness (without cracked or otherwise damaged parts).
  2. Completeness in all details, as specified.
  3. Correctness of settling alignment, set points and relative arrangement of each component.
  4. Confirm that the unit is level within ¼” side to side and end to end.
  5. Inspect unit for leakage and that all mixers are operating as specified.
  6. Inspect coating integrity to insure installation contractor has applied touch-up paint to all scratches, blemishes and/or coating discontinuity that occurred during shipping and installation.

PART 5 – SUGGESTED MANUFACTURER:

The inclined plate clarifier shall be model number # * manufactured by:

Hoffland Environmental, Inc.
10391 Silver Springs Road
Conroe, Texas 77303

(936) 856-4515 phone / (936) 856-4589 fax
e-mail: [email protected]

*Model Number *
*Check following page for alternates.


*COMPLETE BLANKS FROM ATTACHED CHART

HOFFLAND ENVIRONMENTAL, INC.
MOTORIZED RAKE SLUDGE THICKENING BOTTOM SLUDGE HOPPER

MODEL NUMBER
SECTION VARIABLE
2.1.1/2.1.2
2.2.8
2.3.3TORQUE HP
2.3.4
2.6.2
110/60/MA150/60/MA250/60/MA220/60/MB

300/60/MB

500/60/MB

1000/60/MB

440/60/MC

600/60/MC

1000/60/MC

2000/60/MC

2800/60/MC

4100/60/MC

25356055

75

125

250

110

150

250

500

700

1000

1 to 11 to 11 to 12 to 1

2 to 1

2 to 1

2 to 1

5 to 1

5 to 1

5 to 1

5 to 1

5 to 1

5 to 1

2000200052002000

2000

5200

7810

2000

2000

5200

7810

15600

23400

0.120.120.120.12

0.12

0.12

0.25

0.12

0.12

0.12

0.25

0.50

0.50

 4768001500476

800

1500

2300

476

1000

1800

3500

5000

9000

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