section 11330 secondary clarifier equipment secondary clarifier tank dimensions, piping, ancillary...

Southwest Regional WRF: Biological Nutrient Removal Improvements – Project Manual 11330 - 1

January 21, 2016 Secondary Clarifier Equipment

SECTION 11330

SECONDARY CLARIFIER EQUIPMENT

1. GENERAL

1.01 Description

A. Furnish all labor, materials, tools, equipment and incidentals required to install, test,start-up and operate three (3) “new”, hot-dip galvanized steel, clarifier mechanismswith spiral raking blades suitable for installation in the “new” cast-in-place concretesecondary clarifiers (No. 1, No. 2 and No. 3).

B. The work included in this section of the specifications consists of three (3) “new” piersupported spiral style scraper type sludge collector mechanisms with separate scumremoval detailed to fit the “new” cast-in-place circular secondary clarifiers (60 footdiameter) as shown on the Contract Drawings. This equipment shall be constructedsuch that all rotating elements of the mechanisms shall be supported above thewater surface. The equipment furnished for each secondary clarifier shall include,but is not limited to, the following:

1. A stationary center pier column supporting a turntable gear drive, access beambridge with drive service platform, a rotating drive cage frame, rake arm frames,spiral rake blades, RAS manifold troughs, separate skimming trough, inlet feedwell and flocculation baffle.

2. Access bridges

a. Clarifier No. 1: One (1) half diameter access bridge (3'-6" wide) with grating,handrails and kickplate.

b. Clarifiers No. 2 and 3:Two (2) half diameter access bridges on each clarifier,with grating, handrails and kickplate.

3. Center column/influent feed pipe.

4. Fixed spray header.

5. Submersible scum pumping system.

6. Foam suppressing ring.

ADDED VIA ADDENDUM NO. 7



7. Local control panel and controls.

8. Two (2) full radius spiral raking blades and associated appurtenances.

9. Effluent Launders and weirs

10. Scum baffles.

11. Effluent drop box.

C. The secondary clarifier manufacturer shall provide the following:

1. One (1) access walkway connecting the half-bridges from Secondary Clarifiers No. 1 and 2, and therefore providing full walking access from centerline to centerline of the secondary clarifiers.

2. One (1) access walkway from Secondary Clarifier No. 2 to the Reaeration Basin,

and therefore providing full walking access from clarifier centerline to the Reaeration Basin.

3. One (1) access walkway from Secondary Clarifier No. 3 to the Reaeration Basin,

and therefore providing full walking access from clarifier centerline to the Reaeration Basin.

4. The walkway and bridge systems shall include grating, handrails, kickplate and a

walkway support system. D. Related Work Specified Elsewhere

1. Systems Start-Up and Demonstration: Section 01650

2. Site Work: Division 2

3. Concrete: Division 3

4. Handrails and Accessories: Section 05520

5. Grating, Plates and Frames: Section 05530

6. Painting: Section 09900

7. Mechanical: Division 15

8. Electrical: Division 16




E. Coordination

1. The Contractor shall be responsible for coordinating all activities between the

construction of the “new” secondary clarifier concrete tanks and the clarifier equipment manufacturer required for a complete installation. Activities requiring extensive coordination would include, but not be limited to, shop drawing submittals, dimensions, elevations, embedded items required to be installed, and fabrication and installation of the clarifier equipment.

2. Fabrication of the clarifier equipment shall not commence until all key

dimensions, equipment and pipe locations, and any other interdependent items are field verified by the Contractor and the clarifier equipment manufacturer, approved by the Engineer and any conflicts or ambiguities are resolved.

3. It shall remain the Contractor's sole responsibility to resolve any errors or

conflicts arising during construction due to improper coordination between the secondary clarifier tank dimensions, piping, ancillary equipment, appurtenances, etc. and the clarifier equipment manufacturer and installer.

F. Detailed Requirements

1. The basin dimensions of the major items of equipment shall be as follows:

BASIN (SECONDARY CLARIFIER) DIMENSIONS

Process Parameter Value

No. of Secondary Clarifiers 3

Clarifier Construction Cast-in-Place Concrete

Internal Diameter 60 feet

Side Water Depth 14 feet

Total Wall Height 16 feet

Floor Slope 1:12

Influent Pipe 24 inches

Return Sludge Pipe 14 inches

Sludge Pump-Out Line 8 inches

Bridge/Walkway Total Width 3.5 feet

Bridge/Walkway Width (between handrails) 3.0 feet




Effluent Troughs Cantilevered into Clarifier 3.0 feet (from inside wall)

2. The equipment dimensions of the major items of equipment shall be as follows:

EQUIPMENT DIMENSIONS

Process Parameter Value

Diameter of Center Pier Column Diameter 24 inches

Inlet Feed Well Diameter 10.0 feet

Inlet Feed Well Depth 5.5 feet

Scum Troughs 12" (w) x 10" stepped to 14" (d)

Number of Scum Troughs 2 (Galv. Mild Steel)

Effluent Troughs, Weirs, Scum Baffles Galvanized Mild Steel

Effluent Trough Width 24 inches

-Notch Weir Spacing 1½ inches deep on 4-inch centers

Scum Baffles ¼-inch x 12" plates x 10' long

Spiral Scrapers to be Utilized Yes Blade Tapered from 6” to 18”

1.02 Quality Assurance

A. Qualifications

1. The secondary clarifier equipment specified under this Section shall be furnished by a manufacturer who is fully experienced, reputable, and qualified in the manufacture of wastewater process equipment with at least twenty-five (25) years of successful experience building high quality sludge collecting equipment with at least forty (40) installations that may be inspected by the Engineer.

2. Each component and ancillary equipment item furnished under this

specification shall be “new” and “unused”, of the type, size, design, and efficiency installed in previous projects.

B. All electrical equipment and control shall be Underwriters' Laboratories (UL) listed.

C. The equipment specified in this Section shall be furnished, coordinated, serviced and

guaranteed by one manufacturer who shall be experienced in the design, manufacture, coordination, installation, and servicing of equipment of the type, size,




and complexity specified in this Section. The supplier shall have a permanent organization of office and field technical personnel and facilities necessary for fulfilling all requirements of this Specification. The supplier shall have an established service organization in the State of Florida capable of providing fully knowledgeable, experienced service personnel and replacement parts at the Project site not later than twenty-four (24) hours after telephone notification by the Owner. If such a service facility does not exist for the supplier, then the supplier shall guarantee by written notice with their submittal that they shall provide service personnel to the job site upon notification from the Owner within forty-eight (48) hours and shall provide spare parts within twenty-four (24) hours after notification by Owner.

D. Referenced Standards

1. The equipment shall comply with these referenced standards:

a. Anti-Friction Bearing Manufacturer's Association (AFBMA)

b. American Gear Manufacturer's Association (AGMA)

c. American National Standards Institute (ANSI)

d. American Society for Testing and Materials (ASTM)

e. National Electrical Manufacturer's Association (NEMA)

f. American Welding Society (AWS)

E. Standardization

1. All mechanism components, including the center pier column, access beam bridge, drive service platform, spur gear drive assembly, drive cage frame, return sludge/ skimming troughs, suction pipes, influent feed well, drive/pump controls and effluent troughs, weirs and baffles are to be the product of one manufacturing organization.

2. The equipment sizes listed in Article 1.01(F) are estimated minimums. Actual

sizes will be determined by the manufacturer, based on field verification of the dimensions, elevations, piping and appurtenances associated with the two (2) secondary clarifier tanks, and guaranteed to give hydraulic performance of sludge removal without RAS tubes plugging or trough and sight well solids settling at the design loadings.

3. The manufacturer shall design and guarantee the secondary effluent discharge

hydraulics from the effluent launders to the effluent drop box and discharge pipe. The conveyance mechanism (channel and piping) shall be sufficiently sized to ensure that the secondary clarifier shall not backwater outside of the effluent launders.




F. Coordination

1. The Contract Documents provide details of a complete equipment installation for the purpose specified. It shall be the Contractor's responsibility to coordinate all the details required for a complete operating system such as protective coatings and electrical requirements as well as provide all work needed to properly install, adjust, and place in operation a complete working system.

2. Field verification of all tankage dimensions and elevations shall be required prior

to fabrication of the secondary clarifier equipment.

G. Manufacturer’s Quality Control

1. All fabrication shall be carefully inspected at the site of fabrication by factory inspectors who shall use whatever means necessary to assure the proper fit of all field connections and compliance with all material and fabrication requirements of the specifications.

H. Additional Description of Standards

1. All fabricated structural steel shall conform to the requirements of "Standard Specification for Steel for Bridges and Buildings", ASTM Designation A-36. All shop welding shall conform to the latest standards of the American Welding Society.

2. Except where specifically indicated otherwise, all plates and structural members

designated for submerged and non-submerged service shall have a minimum thickness of ¼-inch. All erection and mounting hardware required for the installation of the clarifier shall be corrosion resistant and compatible with the hot-dip galvanized clarifier materials.

3. Fabricated assemblies shall be shipped in the largest sections permitted by

carrier regulations, properly match-marked for ease of field erection. The units shall be erected and lubricated in strict accordance with the instructions of the manufacturer's field engineer.

4. All fabricated steel components of the clarifier shall be hot-dip galvanized unless

otherwise noted on the Contract Drawings or specified herein. Shop drawing submittals shall verify that hot-dip galvanizing is in accordance with the requirements of ASTM A-123.

5. The complete machine shall be of sufficient strength to sweep in cement for the

tank grouted bottom under its own power, if needed. Grouting shall be done in strict accordance with the manufacturer's instructions.




6. Welding

a. The equipment manufacturer's shop welding procedures, welders and welding operators shall be qualified and certified in accordance with the requirements of AWS D1.1, "Welding in Building Construction" of the American Welding Society.

b. Clearly show complete information regarding location, type, size, and length

of all field welds in accordance with "Standard Welding Symbols" AWS A2.0 of the American Welding Society, and fully explain special conditions by notes or details on the equipment manufacturer's shop drawings.

c. The Contractor's welding procedures, welders and welding operators shall be

qualified and certified in accordance with the requirements of AWS D1.1 "Welding in Building Construction" of the American Welding Society.

d. Perform all field welding in conformance with the information shown on the

equipment manufacturer's drawings regarding location, type, size and length of all welds in accordance with "Standard Welding Symbols" AWS 12.0 of the American Welding Society, and special conditions as shown by notes and details.

e. All welding for mild steel components of the clarifier mechanism shall be

continuous and seal welded throughout shop fabrication and field erection. All welds shall be ground to remove all weld spatter and slag. All sharp edges and corners shall be rounded to a smooth contour by grinding.

f. Only minimal field welding of the galvanized steel will be allowed.

g. The manufacturer shall provide a zinc-based cold galvanizing compound to

coat field welds and to repair damage to the hot-dip galvanization.

I. Equipment Manufacturer

1. The clarifier equipment shall be designed, fabricated and installed in accordance with the manufacturer’s recommendations and shall be as manufactured by Ovivo USA, LLC

2. All equipment furnished under this section shall be the product of a single

manufacturer.




1.03 Submittals

A. All material required to establish compliance with the Specifications shall be submitted in accordance with the General Conditions, Supplementary Conditions and Section 13 , “Shop Drawings, Submittals and Samples”. B. All equipment and materials shall be “new”, “unused” and shall be specially

designed or selected for the function and service specified for this facility. No equipment or materials may be used in the Project that has not been approved by the Engineer.

C. Submittals shall include, but are not limited to, the following:

1. Shop drawings complete with equipment catalog cut sheets, all dimensions,

anchor locations, openings required in structures, details of connecting piping and the size and location of any required electrical conduits and conduit openings.

2. Cross-sectional drawings of all equipment with parts identification and materials

specifications.

3. Fabrication and erection drawings.

4. Specifications for the main spur gear drive, the torque monitor, all mechanical and electrical components; and complete wiring diagrams for all electrical equipment.

5. Details of the major fabricated components showing the arrangement of devices

and labeled with member sizes and materials of construction.

6. AGMA torque and strength calculations for the main spur gear drive bearing.

7. Structural calculations for the access beam bridge, center pier column, drive cage frame, return sludge trough and rake arm frames.

8. Structural calculations for the access walkway between the secondary clarifiers

and details of the supporting and mounting system.

9. Manufacturer's recommended procedures for jobsite storage of equipment, handling and erection.

10. An installation list of facility’s, contact names, phone numbers to verify the

experience requirement as required by Article 1.02(A)(1).

11. Total Weight of all equipment and the single largest item or component.

12. Bill of Material.




13. Piping details of connections to existing piping.

14. Galvanizing specification(s) for ferrous surfaces.

15. Electrical schematics and interconnecting wiring diagrams showing the extent of factory pre-wiring and details of control panels.

16. Special tools to be supplied.

17. A list of manufacturer’s recommended spare parts to be supplied with the

manufacturer’s SKU number and current price for each item.

18. List of local facilities to obtain parts for all equipment.

19. Test data for equipment as specified herein.

20. List of manufacturer approved service organizations for all equipment.

21. List of recommended grades of lubricants with at least two (2) alternate references.

22. Operation and Maintenance Manuals in accordance with Section 01730,

“Operation and Maintenance Data”.

23. Separate AWS certificates (certification required within the past year) for all fabrication shop and field welders performing welds on the equipment.

24. All shop drawings and calculations shall be certified and sealed by a registered

Professional Engineer if deemed necessary by the Engineer.

D. Operation and Maintenance (O&M) Manuals

1. Operation and Maintenance Manuals shall be furnished for this Project in accordance with Section 173 , “Operation and Maintenance Data” and shall be submitted in accordance with Section 13 , “Shop Drawings, Submittals and Samples”.

2. The O&M Manuals shall be prepared specifically for this installation and shall

include all detailed operating and maintenance instructions (normal, shut-down, start-up and emergency) and specifications relative to the assembly, alignment, checking, lubrication, placing in operation, adjustment, and maintenance of equipment and auxiliaries furnished under this Contract, together with its complete parts lists therefore, and copies of shop drawings, certified dimensions drawings and design calculations, required cut sheets, drawings, equipment lists,




descriptions, etc. that are required to instruct operation and maintenance personnel unfamiliar with such equipment.

3. A troubleshooting guide shall be provided that identifies all potential equipment problems and potential solutions or corrective actions.

4. All required maintenance instructions (routine and preventive) including

schedules shall be provided.

5. The name, address, phone and FAX numbers, and e-mail address of the nearest competent service organization who can supply parts and service. If this is not the manufacturer’s own service department, then furnish letters confirming the named organization has been factory authorized to represent the manufacturer of the equipment furnished.

6. Complete “As-built” erection drawings and wiring diagrams providing up-to-date

information on the actual construction of the equipment furnished and any field modifications made during installation or start-up.

7. All such material shall be in addition to any instructions or parts lists packaged

with or attached to the equipment when delivered.

8. A list of all spare parts to be provided to ensure proper operation of the equipment for a period of two (2) years from the date of Final Project Acceptance by the Owner.

9. The “final” O&M Manuals shall contain plastic laminated pull-out lubrication

and maintenance cards detailing all lubrication points, lubricant type, and frequency of lubrications and all additional required maintenance and frequency intervals.

10. In addition to standard O&M Manuals, all manufacturers supplying

equipment and products specified herein shall also submit their operation and maintenance manuals and data to the SCADA System Integrator (Krüger, Inc., Cary, NC) for this Project on CD/DVD/BD’s in Corel WordPerfect (latest version), Microsoft Word (latest version), or text, "txt", formats. All graphic files shall be in BMP, PCX, CDR, JPEG, DWG or DXF formats (integrators preference for the system shall be required). All O&M Manual files shall also be submitted electronically on CD/DVD/BD’s to the Engineer in both PDF and JPEG formats, no exceptions.

11. The SCADA System Integrator (Krüger, Inc., Cary, NC) shall be responsible

to configure and compile the O&M Manuals into “hypertext” window help files for use as computer “on-line” help screens for equipment operation and maintenance. The SCADA System Integrator shall return all hypertext files to the equipment and product manufacturer’s for review and approval prior to introducing them into the SCADA System at the treatment facility.




1.04 Product Delivery, Storage and Handling

A. Preparation for Shipment

1. All pieces shall he delivered in the largest pieces practical for field assembly by the Contractor. Individual pieces shall be tagged with erection marks or tags cross referenced with information on the manufacturer's erection and assembly drawings.

2. Gear boxes, mechanical and electrical components shall be protected from the

weather and suitably packaged to facilitate handling and storage.

3. Special lubricating and rust preventative oils shall be provided to prevent internal corrosion of gear assemblies.

4. All mechanical equipment shall be kept thoroughly dry at all times and

shall be stored indoors.

B. Storage of Equipment

1. All equipment stored on the job shall be protected and maintained in accordance

with the manufacturer's recommendations.

2. Electrical equipment must be stored in weatherproof, ventilated enclosures.

3. Structural materials may be stored outdoors on pallets or other wooden supports providing for the proper support and drainage. Equipment shall not be allowed to contact the ground directly.

C. Shipment

1. The equipment manufacturer shall maintain storage facilities for completed

equipment such that in the event that proper storage facilities are not available on the jobsite that the manufacturer and Contractor will have the option of storing finished goods off site for delivery to the project within two (2) weeks notice from the Contractor.

D. Equipment shall be transported, stored and handled on-site in accordance with

Section 16 , “Materials and Equipment”.

E. All equipment shall be delivered in suitable packages, cases or crates, and stored

and placed as directed. Each package shall have an identifying mark or a complete list showing contents.




1.05 Warranty

A. The Contractor shall furnish the Owner with a full two (2) year service/parts warranty as specified in Section 174 , “Warranties and Bonds”.

B. The clarifier equipment shall be unconditionally warranted by the manufacturer

for a period of two (2) years from the date of Final Project Acceptance by the Owner.

C. The equipment manufacturer shall guarantee that the equipment furnished is suitable

for the purpose intended and free from defects of design, material and workmanship. D. In the event that any equipment fails to perform as specified, the equipment

manufacturer shall promptly repair or replace the defective equipment at no additional cost to the Owner.

E. This warranty is in addition to any other warranty required by the Contract

Documents.

1.06 Manufacturer’s Services

A. Prior to equipment delivery, the manufacturer shall furnish jointly to the Engineer and Contractor a minimum of three (3) sets of complete installation, operation and maintenance manuals which shall include assembly/erection drawings, as-built drawings of electrical equipment, assembly details, parts lists, and detailed written instructions for the installation, operation and maintenance of the equipment furnished.

B. The Contractor shall provide the services of a competent and experienced

equipment manufacturers factory field engineer to supervise start-up and provide training to the Owner's personnel.

C. The manufacturer’s field factory engineer shall be available for one (1) trip consisting

of two (2), eight (8) hour days, to inspect and supervise the installation of the equipment in accordance with Section 143 , “Manufacturer’s Services”.

D. The Contractor shall install all equipment in exact accordance with the

manufacturer's written instructions and as directed on the jobsite during inspection visits by the manufacturer's technical representative.

E. Deviations from the manufacturer's written or verbal instructions shall be subject to

approval by the Engineer and discrepancies or unsatisfactory work shall be reported in writing by the equipment manufacturer's representative jointly to the Engineer and Contractor.




F. Within ten (10) days after the final inspection of the completed installation, the manufacturer's representative shall furnish a detailed report jointly to the Engineer and Contractor which shall list any deficiencies found in the work and which shall recommend corrective action for each deficiency. Upon completion of any corrective action required, the manufacturer shall furnish a letter certifying that the equipment is properly installed and ready for the operation and beneficial use by the Owner.

G. The manufacturer’s field factory engineer shall be available for one (1) trip consisting

of two (2), eight (8) hour days for inspection of final leveling, alignment, tensioning and lubrication of the installed equipment and a detailed check of the completed work and supervise the start-up demonstration and testing as specified in Section 165 , “Systems Start-up and Demonstration”.

H. Upon completion of installation by the Contractor and startup of the equipment by the

manufacturer's field service representative, the equipment shall be operated under the supervision of the Contractor for a minimum of eight (8) hours to ensure that all clearances, vibrations, tracking and motor operating characteristics are within acceptable limits.

I. Operation and Maintenance Training

1. The factory field engineer shall provide training to the Owner's personnel on all

operations and maintenance associated with the Secondary Clarification System equipment. Training of the Owner's personnel will only be considered valid for approval by the Engineer if it takes place after the successful Start-up and Demonstration Test.

J. The costs associated with the manufacturer’s services stated herein shall be

incorporated into the Contractor’s Bid Price for this Project. K. The Contractor shall provide HD recordings (audio-visual) of the training and

maintenance sessions as part of this Contract and provide three (3) copies of the HD recording, on DVD/BD, to the Engineer for distribution.

2. PRODUCT'S 2.01 General

A. The clarifier mechanism shall be of the center drive type, supported on a stationary center pier column, with the influent flow entering at the bottom of the influent column and flowing upward to the inlet openings near the water level. The clarifier shall be designed to remove sludge uniformly from the bottom of the secondary clarifier basin using a spiral raking blades system.




B. Equipment furnished and installed under this Section shall be fabricated, assembled, erected and placed into service in proper operating condition in full conformity with the Contract Drawings, specifications, engineering data, field obtained data on the “new” clarifier basins, instructions and recommendations of the equipment manufacturer unless exceptions are noted by the Engineer.

C. Structural Design

1. The design loading for the clarifier drive unit and for the structural analysis of the

drive cage, rake arms, and center pier shall be taken as all dead loading resulting from the weight of all rotating equipment, plus a live load equal to 2.25 times the continuous output torque rating of the spur gear drive as described in Article 2.02(A)(10).

2. The maximum allowable combined stress in any member at this loading

shall not exceed 20,000 psi.

3. The structural design of the mechanisms and access bridges, including allowable stresses and slenderness ratios, where applicable, shall be in accordance with the American Institute of Steel Construction Specification for Steel Bldgs (latest edition).

4. Design of clarifier components shall prevent any unusual warpage that is

functionally and aesthetically unappealing during the fabrication process.

5. Design calculations verifying these conditions are to be submitted in accordance with Article 1.03(C)(7-8).

D. Carbon Steel Fabrication

1. All submerged components of the collector mechanism including the center pier,

drive cage, collector arms, flights, squeegees, influent well and supports, scum trough, scum skimmer arm and scum wiper, and scum beach shall be fabricated from a minimum of ¼-inch thick A-36 carbon steel.

2. All welding techniques and sizes shall conform to the latest AWS Standards and

shall be performed by qualified welders. All welding shall be a minimum of 3/16-inch fillets, and shall be the full length on all mating surfaces. Welds shall be free of porosity and cleaned for removal of weld flux and impurities that would prevent adhesion of the molten zinc during the hot-dip galvanizing process.

3. All field connections shall be bolted connections designed to resist all static, live

and erection loads. Field welded assembly will not be allowed. All bolted structural connections shall be gusseted as required to prevent deflection with a minimum 3/16-inch thick steel plate. Main structural connections shall use a minimum of ¾-inch diameter bolts. Secondary structural connections shall use a minimum of two (2) ⅝-inch diameter bolts.




E. Stainless Steel Fabrication - NOT USED

F. Hot-Dip Galvanizing

1. All fabricated carbon steel components of the access bridge, drive service platform, slide plates, scum piping and supports and all wetted components of the mechanism shall be manufactured of A-36 carbon steel (¼-inch minimum thickness) and hot-dip galvanized (HDG) after fabrication in accordance with ASTM A-123.

2. Pieces shall be fabricated in maximum sizes suitable for shipping and

galvanizing. The clarifier equipment and components shall be designed and fabricated per ASTM A-143, A-384, and A-385 for bolt together field assembly. No field welding on hot-dip galvanized equipment will be permitted.

3. All welding techniques and sizes shall conform to the latest AWS Standards and

shall be performed by qualified welders. All welding shall be a minimum of 3/16-inch fillets, and shall be the full length on all mating surfaces. Welds shall be free of porosity and cleaned for removal of weld flux and impurities that would prevent adhesion of the molten zinc during the hot-dip galvanizing process.

4. Minor defects in the hot-dip galvanizing coating caused by shipping, handling or

installation shall be repaired after equipment installation. The defects shall be thoroughly cleaned and wire brushed to remove all foreign substances, wiped clean with a suitable solvent, thoroughly dried, and coated with at least three (3) mils of a zinc-rich compound (supplied by the Contractor) specifically formulated for touch-up of galvanizing and conforming to USN Specification MIL-P-21035 or USAF Specification MIL-P-26915A.

5. All galvanized members delivered to the Project Site shall be stored by the

Contractor in a position where they are raised off of the ground and well separated to provide ventilation and drainage.

G. Structural Connections

1. All field connections shall be bolted connections designed to resist all static, live, and erection loads. Field welded assembly will not be allowed.

2. All bolted structural connections shall be gusseted as required to prevent

deflection with minimum 3/16-inch thick steel plate. Main structural connections shall use a minimum of two (2) 5/8-inch diameter bolts.

3. Secondary structural connections shall use a minimum of two (2) 1/2-inch

diameter bolts.




4. Galvanized fasteners shall be used to attach hot-dip galvanized equipment

items.

H. Anchorage and Fasteners

1. All structural fasteners, including the tie-rods, shall be hot-dip galvanized.

2. All cast-in-place equipment anchorage, including nuts and washers shall be of AISI Type 18-8 (300 series) stainless steel. The minimum size of any cast-in-place anchor shall be ¾-inch diameter.

3. All installed anchors shall be of the drop-in style (hole size equals bolt size), and

shall conform to Federal Specifications GSA FF-S-325, Group II, Type 4, Class 1. Anchor bolts shall be Type 18-8 (300 series) stainless steel with clips, nuts and washers to be Type 18-8 (300 series) stainless steel. The minimum size of any drop-in anchor shall be ½-inch diameter.

2.02 Construction and Materials

A. Gear Drive Mechanism

1. The center drive assembly shall consist of an integral motor and primary speed reducer coupled through roller chain and sprockets to a secondary worm/worm gear reducer driving the main gear through a pinion and shall have an integral overload protection system.

2 All gears and bearings shall be oil bath lubricated with the main bearing totally

submerged in oil and the teeth of the main spur gear submerged at least 70 per cent in the oil bath. Oil pumps for lubrication or grease lubricated bearings are not considered appropriate for this application and will not be allowed. The oil reservoir for the main bearing and gear shall have a section of minimum depth 5 inches below the main bearing to positively prevent contamination of the main bearing and gears with condensate or other contaminants. Gear and bearing housings must also be fitted with oil level sight glasses and condensate drains. Condensate must be allowed to drain from a low point of the housing. Condensate and contaminants will not be allowed to drain through the lower pinion bearing.

3. Drive components will be located via a machined, registered fit to preserve the

alignment of key drive components under all load conditions. Inspection of the completed drive unit shall be accomplished at the clarifier manufacturer's shop, with reports of all tests and certifications of material hardness being made available for review at the Engineer's request prior to shipment to the job site.




4. Major drive components, main gears and bearings must be designed to allow for

separate and individual replacement by plant personnel to facilitate quick and economical repairs.

5. The complete center drive assembly, including the overload protection device,

shall be a regularly manufactured in-house product of the clarifier manufacturer. The center drive assembly is a key element in a successful clarifier installation, therefore drive assemblies purchased from third party vendors will not be accepted.

6. The drive motor shall be minimum 3/4 horsepower and shall be totally enclosed,

fan cooled, with a 1.15 service factor, and have bearings with a minimum B10 rating of 50,000 hours. Operating electric current will be 230/460 volt, 3 phase, and 60 hertz. Each motor will be NEMA Design B employing Class F insulation designed for an ambient temperature of 40 degree. C.

7. The gearmotor primary speed reducer shall drive a secondary worm gear

reducer through a #60 roller chain and steel sprockets enclosed in a galvanized 22 gauge steel guard. A constant speed motor shall drive the speed reducer. Sprockets and chain shall be designed for the connected horsepower of the drive with a minimum service factor of 4.0. Provision shall be made for adjustment of chain tension.

8. The main drive unit shall consist of a worm gear secondary reduction unit, pinion

and main spur gear assembly. The secondary reducer shall be a worm/worm gear reducer specifically designed for this application. The worm gear shall be centrifugally cast high strength manganese bronze. The worm shall be hardened alloy steel. A single piece pinion shall be keyed to the worm gear to transmit power from the worm gear to the spur gear. In order to maintain proper alignment between the pinion and the spur gear, the pinion will be supported by bearings both above and below the spur gear. The bearings shall be fitted into precision machined bearing pilots to positively insure bearing and gear alignment.

9. The main spur gear material shall be high strength ductile iron per ASTM A536

grade 80-55-06 or equal. The gear shall have a nominal pitch diameter of 30 inches with a 4.75 inch face width or the equivalent nominal spur gear surface area of 447 square inches. Spur gear surface area is defined as the spur gear pitch diameter multiplied by the spur gear face width multiplied by 3.14.

10. The main gear shall rotate and be supported on a ball bearing assembly provided

with four replaceable liner strips fitted into the main gear and turntable base. Liner strips shall be special vacuum degassed carbon corrected alloy steel hardened to a Rockwell hardness of at least 43 to 46 RC. The turntable base shall be a minimum 1 inch thick to insure adequate structural rigidity to properly support the drive bearing and gear.




11. The main gear and bearing shall be completely enclosed in an ASTM A-48 Class 30A cast iron housing provided with neoprene dust seals. In order to ensure the maximum possible base rigidity and vibration dampening, the gear housing shall be of full sidewall construction, integral with the base. Prior to assembly, the base shall be thoroughly inspected for seep holes or inclusions and given a hydrostatic test to insure no leaks are in the oil containment area. Shop inspection reports must be made available for review.

12. The drive unit shall be equipped with an electro-mechanical overload control

device actuated by thrust from the worm shaft. The pointer shall provide a visual reading of the relative main gear output torque on a 0 to 100 percent graduated scale. The 100 percent reading shall equal the 100 percent drive rating as specified in section 1.03. The control device shall also activate an alarm switch for warning of impending overload, a motor cutout switch for overload protection and a back-up safety motor cutout switch for back up overload protection. In lieu of a back-up safety motor cutout switch a slip clutch assembly will be acceptable upon review by the Engineer. The respective switches in the overload control device shall be factory calibrated and set to the following settings:

a. Alarm - 40% of scale b. Motor cutout - 85% of scale c. Back-up motor cutout or slip clutch - 100% of scale.

All drive control components shall be mounted in a weatherproof enclosure of either epoxy coated aluminum construction or stainless steel with a gasket-sealed, removable cover. The pointer shall be covered with a clear plastic enclosure and shall be above the walkway surface for visibility from the walkway. Amperage sensing devices are not acceptable for torque overload protection due to their inability to react quickly enough to prevent damage to the drive. Overload devices with exposed linkage connections will not be accepted due to possible corrosion problems. Devices which react to rotational movement of the secondary reduction unit will not be allowed due to possible misalignment of gearing created by the movement of the reduction unit.

13. The center drive unit shall be designed for the continuous torque rating as

specified in section 1.03. The continuous torque shall be defined as the minimum torque at which the drive mechanism may operate continuously 24 hours per day, 365 days per year, for 20 years, at the specified sludge collector arm speed. Main gear and pinion calculations shall be based upon ANSI/AGMA 2001-C95 standards for rating the pitting resistance and bending strength of involute spur and helical gear teeth. Calculations shall clearly present the values used for the following design parameters:

1. Number of pinions 2. Actual face width 3. Tooth geometry (I and J factors) 4. Load distribution factor 5. Allowable contact stress




6. Allowable bending stress 7. Pinion pitch diameter 8. Hardness ratio factor 9. Elastic coefficient 10. Life factor

The load distribution factor shall be determined by the empirical method. For

parameters which are material dependent, such as allowable contact stress, the calculations shall include a complete description of material and heat treatment used.

Worm gearing shall be designed and rated to equal or exceed the specified

continuous torque and life. The basis for rating shall be ANSI/AGMA 6034-B92 standards for durability rating and design of worm gear reducers.

The continuous torque rating for the drive unit shall be the lowest value

determined for the gearing.

B. Drive Control Panel

1. The manufacturer of the sludge collector equipment shall provide a local drive control panel mounted to the drive service platform handrail of the mechanism. The interconnecting wiring and conduit shall be provided by the Contractor.

2. The drive control panel shall be a NEMA Size 1 combination starter with 3 leg

thermal overload protection and external reset, including a circuit breaker with flange mounted visible disconnect switch, all in a NEMA 4X stainless steel oversized enclosure. Additional devices mounted within the enclosure shall include:

a. A fused 0.5 kVA control power transformer.

b. Overload relay, pending overload relay, and alarm silence relay.

c. Terminal strips for connecting the overload and alarm contacts located in the

drive torque monitor.

3. External controls shall be weatherproof NEMA 4X corrosion resistant and shall include:

a. A pull-to-start, push-to-stop, illuminated run switch.

b. Alarm silence push-button.

c. An overload reset push-buttons.




4. A weatherproof combination horn and light fixture with 100 watt bulb shall be mounted to the top of the enclosure. Provide dry contacts in the control panel for both the clarifier drive motor, scum pump motor, and pending and final overloads signals back to the SCADA system.

5. The Contractor shall provide 460 volt, 3-phase, 60 Hz electrical power to the

control panel and all interconnecting wire and rigid conduit between the control panel and the torque monitor mounted to the spur gear drive.

C. Center Pier Column

1. The manufacturer shall provide a circular steel center pier. The top of the center pier shall provide a stable and accurate surface upon which the main gear may be mounted. The center pier shall support the main gear, access truss bridge, drive service platform and the entire weight of the rotating mechanism.

2. The center pier shall be sized as indicated in Article 1.01(F)(2) and shall be constructed of a minimum ¼-inch thick carbon steel plate or steel pipe. The pier shall be provided with minimum one (1) inch thick steel plate top and bottom flanges. The top flange shall have mounting holes matching the main spur gear drive. The bottom flange shall be provided for mounting to the center pier anchorage. The equipment manufacturer shall provide eight (8) 1-inch diameter by 12-inch long, Type 304 stainless steel hookbolts with nuts/washers and epoxy capsules for center column anchorage.

3. A minimum of four (4) outlet ports shall be provided at the upper end of the pier

with the top edge of the port opening at least three (3) inches above the liquid level. The total clear open area of these ports shall be determined by the equipment manufacturer; but as a minimum, shall be greater than or equal to the area of the clarifier influent feed pipe.

4. The mechanism shall be provided with components to remove surface scum from

the inner annular space between the scum ring and the feedwell and between the feedwell and the scum baffle as detailed in the drawings and described in this section. Two rotating scum troughs located 180 degrees apart shall be provided for the inner and outer annular space. The troughs shall collect and remove surface scum from the entire surface of both the inner and outer annular space. The troughs shall be equipped with continuous approach beach. The design shall allow the supports for the scum trough to be adjusted 2 inches vertically to account for possible settlement of secondary sedimentation tank.

5. A scum blade shall be supported from the access bridge. The blade shall consist of a backing plate and a flexible blade. The stationary scum blade shall be designed to push surface scum from the flocculation zone by the blade scraping the scum troughs as they rotate past the scum beach. The blade shall extend above and for the full horizontal distance between the diffuser tub and the




secondary baffle. Provisions shall be made in the design of the scum blade support to permit 2 inches vertical adjustment to account for possible settlement of the secondary sedimentation tank.

6. A scum collection sump shall be provided for scum discharge from the scum troughs. The scum collection sump shall be located concentrically around the center column and supported from the center cage. The scum collection sump shall have dimensions as shown on the drawings. A stationary scum pump shall be supported from the platform above and extend to the bottom of the scum collection sump. The pumps shall collect and discharge scum into the scum box of outer annular ring near the perimeter of the tank. The scum force main shall be supported by the walkway.

7. Structural calculations confirming that the center pier is of adequate size to

support the weight of the mechanism and stall torque of the drive shall be submitted to the Engineer in accordance with Section 13 , “Shop Drawings, Submittals and Samples” and this specification section.

D. Drive Cage Frame

1. A center rotating drive cage frame shall be furnished to provide an attachment structure for the sludge collector arms, scum troughs and influent well. The drive cage shall be completely supported and stabilized by the main gear bearing. No below water supports, bearings or bumpers will be allowed.

2. The 2'- 10" square drive cage shall be fabricated from minimum ¼-inch thick

carbon steel plate and shapes, be shop welded and for field bolted connections. All carbon steel shall be hot-dip galvanized.

3. The drive cage shall be designed as a box truss for the load conditions described

in Article 2.01©. Calculations confirming that the cage details meet these requirements shall be submitted for approval by the Engineer in accordance with Section 13 , “Shop Drawings, Submittals and Samples” and this specification section.

E. Scum Collection Trough/Box

1. One (1) 12-inch wide tapered scum collection trough with approach ramp shall be mounted to the supports extending from the rake arms and influent feed well wall. This trough shall be on the inside of the influent well and trap and remove scum at this location. There shall be a pivoting scum wiper mounted from the bridge to pull the scum up the inclined beach and deposit it into the scum trough.

2. A 1'-6" deep x 5’-0" ID scum collection sight well surrounding the center cage

shall be provided to collect scum into the scum ports located at the top of the pier.




F. Scum Removal Pump

1. The clarifier manufacturer shall furnish a submersible scum removal pump for

mounting in the scum collection chamber .

2. The scum removal pump will be a Wemco Hidrostal submersible pump for handling the scum and scum water collected to the scum box inside the inlet feed well. The pump shall be designed to remove the types of solids collected in a normal municipal scum removal system at a rate of 80 to 100 GPM.

3. A 3-inch diameter galvanized carbon steel scum discharge pipe will be provided

extending from the submersible scum pump to the end of the clarifier access bridge and terminate plain end at the edge of the concrete wall. The Contractor shall connect to this pipe and convey the scum to the location indicated on the Contract Drawings.

4. Pump controls (combined with the drive control panel) shall be provided for

automatic timed operation of the scum pump. Pump shut-off will be by an adjustable timed delay to create scum pumping times of 30 seconds to 5 minutes at a pumping rate of 80 to 100 GPM. The pre-wired control panel will include all necessary starters, disconnects, controls for the intended pump operation and meet NEMA and local electrical codes.

G. Rake Arm Frames and Sludge Return Troughs

1. The sludge collector mechanism shall have two (2) collector rake arm frames with spiral flights arranged to sweep the floor twice each revolution with concurrent supports for the rotating scum trough skimming the clarifier surface between the influent well and the scum baffle.

2. The center cage shall be of steel box truss construction, with connections for the two (2) sludge removal arms, rotating sludge collection drum and feedwell supports. The top of the cage shall be bolted to the main gear which shall rotate the cage with the attached arms and feedwell. The minimum angle size used for construction of the cage and rake arms shall be 2 inch x 2 inch x 1/4 inch members.

3. The clarifier mechanism shall include two (2) sludge removal arms of steel truss construction, with steel spiral rake blades and adjustable 20 gauge 304 stainless steel squeegees. The rake blades shall provide complete raking of the basin floor twice per revolution.

4. The rake blades shall consist of a minimum 3/16 inch thick steel plate. The blades shall be constructed to a logarithmic spiral curve with a constant 30 degree angle of attack. Blade depth shall vary for 6” at the tank wall to 18” in the tank center. Each rake truss support arm shall be provided with the necessary outrigger bracing and




other blade support structures, to ensure that the complete blade can be properly located and adjusted in the field.

5. The rake blades shall terminate in the center to within 1 inch of the rotating sludge collection drum. The 1 inch space shall be sealed with a neoprene seal.

H. Rotating Sludge Collection Drum 1. A rotating sludge collection drum shall be provided to collect settled solids raked to

the center by the rotating spiral blades. The collected sludge shall be discharged from the tank by way of the RAS sludge pipe as shown on the contract drawings.

2. The sludge collection drum shall rotate with the center cage and shall be provided with sludge collection ports located directly in front of each rotating spiral rake blade. The ports shall be sized to collect thickened sludge from the bottom most dense sludge layer to maximize underflow solids concentration.

3. The rotating sludge drum shall be constructed of ¼ inch steel plate. A neoprene seal shall be provided to seal against the center column. A stainless steel seal shall be provided to seal against the tank floor.

4. Calculations confirming that the flight arm meets these requirements shall be

submitted for approval at the Engineer’s request.

I. Access Bridge and Service Platform

1. Access Bridges

a. A 3'-6" foot wide (3'-0" foot clear opening between handrails) fixed access bridge, walkway and drive service platform shall be furnished to provide access to the center drive assembly. The bridge shall span one-half of the secondary clarifier tank as indicated on the Contract Drawings, and shall be supported at the tank walls and the main spur gear drive assembly. The following access bridges shall provided by the clarifier manufacturer, as shown on the Contract Drawings, and indicated below:

Clarifier No. Access Bridge Requirement*

1 One (1) access bridge, running east-west from the service platform at center of clarifier to outer wall.

2 Two (2) access bridges, one running east-west from the service platform at center of clarifier to outer wall and the other running north-south from the service platform at center of clarifier to outer wall.

3 Two (2) access bridges, one running east-west from the service platform at center of clarifier to outer wall and the other running north-south from the service platform at center of clarifier to outer wall.




* See Contract Drawings for location and alignment of the access bridges. The access bridge systems

shall include grating, handrails, kickplate and a walkway support system.

b. The bridge shall consist of two (2) structural steel wide flange beams interlaced with cross angles and diagonal angles for rigidity. Structurally, the bridge shall be designed such that the maximum deflection shall be limited to 1/800 of the span, with all dead loads plus a live load of 100 lb/ft2 on the walkway. The manufacturer shall be responsible for sizing the bridge members to meet these requirements; except, that the members specified are the minimum acceptable.

c. Two (2) slide plates shall be provided at the clarifier side walls to allow for

thermal expansion. The slide plates shall be a minimum of ½-inch thick steel plate (hot-dip galvanized).

d. The bridge shall be provided with a minimum 3.5 foot wide walkway (3.0

foot from inside of handrail to inside of handrail) designed to allow for an uninterrupted passage along its entire length across the clarifier basin. The access walkway shall consist of removable hot-dip galvanized carbon steel grating sections, 1½" x 3/16" x 1" clear openings and ¼-inch thick by 4-inch high aluminum kickplate. No individual removal grating section shall weigh more than 80 lb.

e. A drive service platform shall be provided to allow easy maintenance of the

gear drive assembly. The platform shall be a minimum of eight (8) foot square fabricated from 6-inch deep (minimum) channel shapes and angles. The platform shall be covered with removable ¼-inch thick aluminum checkered floor plate and shall include aluminum handrails and 4-inch high anodized aluminum kickplate.

f. Anodized aluminum handrails shall be assembled from 1½-inch Schedule 40 aluminum pipe shall be provided for both sides of the access bridges, service platforms and access walkway. The railing shall be a two rail system with the top rail located at forty-two (42) inches above the deck and include a 4-inch wide anodized aluminum kickplate. Sections shall be field assembled with cast aluminum fittings. The handrail system shall be a product of Golden Rail, or approved equal, and comply with all current OSHA standards.

2. Access Walkways

a. The secondary clarifier manufacturer shall provide three (3) access walkways connecting the following:




1. One (1) access walkway connecting the half-bridges from Secondary Clarifiers No. 1 and 2, and therefore providing full walking access from centerline to centerline of the secondary clarifiers.

2. One (1) access walkway from Secondary Clarifier No. 2 to the Reaeration

Basin, and therefore providing full walking access from clarifier centerline to the Reaeration Basin.

3. One (1) access walkway from Secondary Clarifier No. 3 to the Reaeration

Basin, and therefore providing full walking access from clarifier centerline to the Reaeration Basin.

b. The access walkway systems, identified above, shall be the same width as

the access bridges and include grating, handrails, kickplate and a walkway support system (to be designed by the clarifier manufacturer). An aluminum stairway, from the ground surface to the top of the Reaeration Basin, shall be provided by the Contractor and shall provide “total” access between all Secondary Clarifiers and the Reaeration Basin as indicated on the Contract Drawings.

c. Structurally, the access walkways shall be designed such that the maximum

deflection shall be limited to 1/800 of the span, with all dead loads plus a live load of 100 lb/ft2 on the walkway. The manufacturer shall be responsible for sizing the bridge members to meet these requirements; except, that the members specified are the minimum acceptable. The Contractor and clarifier manufacturer are responsible for accurate measurements of the cast-in-place concrete structures to ensure the walkways are fabricated and constructed to the correct elevations indicated on the Contract Drawings (cast-in-place concrete pedestals shall be constructed to ensure the proper walkways elevations to allow for vehicular traffic below the walkways).

J. Scum Collection System

1. A scum holding curtain shall be mounted from the bottom of the bridge to stop the rotation of the scum and to help push it into the scum trough. The curtain shall span the area between the influent well and the drive cage.

2. A galvanized steel spray header shall be installed that spans one-half the

clarifier, supported beneath the access bridge, with multiple nozzles to form a curtain forcing the scum on the water surface outside the influent well and inside the scum baffle into the RAS trough scum ports.

3. One (1) foam suppressant spray assembly shall be installed to provide water

around the center column just below the gear drive. The foam suppressant assembly to be field assembled from 1-inch galvanized steel pipe and fittings and include five (5) PVC cone shape nozzles, solenoid valve, and 1-inch true-union




plug valve for flow control and throttling. A 1-inch galvanized steel water supply pipe shall be supported from the walkway handrail near the mid-rail handrail with a cast iron Y-strainer with blow-off valve. The Y-strainer shall be located near one end for easy access from the walkway.

4. This inner spray system shall be supplied for both “manual” and “automated”

operation. Automated operation shall coincide with the scum pump operating cycle.

K. Octagonal Flocculation Baffle

1. The clarifier influent shall exit the influent ports in the center pier and be directed toward the water surface while velocities are being reduced and diffused and scum directed to the water surface inside the octagonal flocculation baffle.

2. The flocculation baffle shall be fabricated from 3/16-inch thick steel plate and

transition from the square shape of the drive cage to an octagonal shape at the top, terminating 20 inches below the water surface.

3. The flocculation baffle shall have a split floor plate that bolts to the drive cage

and comes to within 1-inch of the outside diameter of the center pier.

4. All materials shall be hot-dip galvanized.

L. Influent Upward Feed and Diffusion Well

1. The clarifier influent shall pass through an influent feed well sized as indicated in Article 1.01(F).

2. The influent well shall be fabricated from 3/16-inch thick steel sheet, supported by

structural channels attached to the drive cage using minimum ¾-inch diameter fasteners.

3. The influent well shall be supported by and rotate with the drive cage frame.

Four (4) 10-inch deep steel channels shall be provided to support the inlet well.


M. Effluent Troughs/Launders

1. Galvanized steel inboard effluent weir troughs shall be furnished as shown on the Contract Drawings. The troughs shall be furnished in individual segments approximately ten (10) feet in length. One trough segment shall have a drop box with a plain end ductile iron pipe for connection to the effluent discharge box just




outside the clarifier tank wall. Connection shall be by means of a sleeve type pipe coupling or wall pipe. The effluent troughs shall be individually supported by heavy fabricated knee braces (hot-dip galvanized) anchored to the concrete wall. The effluent troughs will be sized by the clarifier manufacturer for 3Q peak flow with three (3) inch minimum free fall.

2. The individual trough sections shall be adequately braced and supported so that

a deflection of less than ⅛-inch shall occur under the assumption that the tank is full and the troughs are empty. The individual trough sections shall be formed of a minimum ¼-inch thick steel plate.

3. The individual trough sections shall be spliced over the knee braces with a bolted

splice that is sealed by a continuous neoprene gasket backed by three sides of splice bars, fabricated of a minimum ¼-inch thick steel plate. A minimum of eleven (11) bolts shall be used at each splice, three (3) of which shall be a minimum of ⅝-inch in diameter to be used to secure the trough to the knee brace. The remaining splice bolts shall be minimum of ½-inch in diameter.

4. The knee braces shall be fabricated of minimum 4" x 4" x ¼-inch steel angle

vertical and horizontal members with a minimum 3" x 3" x ¼-inch diagonal brace. The knee braces shall be anchored to the wall with a minimum of three (3) ⅝-inch diameter drop-in anchor bolts. All welding on the knee braces shall continuously seal lapped or joining surfaces.


6. The effluent troughs/launders shall be installed three (3) feet inward from the

interior wall of the clarifier.

N. Effluent Weirs

1. Weir plates shall be furnished for mounting to both sides of the effluent troughs. Oversized holes shall be provided in both the trough and the weir plate to provide vertical and horizontal adjustment. The weir plates shall have -notches, 1½ inches deep and installed on four (4) inch centers.

2. The weir plates shall be fabricated from ¼-inch thick galvanized steel, minimum,

and shall be no less than six (6) inches tall.

3. The weir plates shall attach to the trough sections with a minimum of ½-inch diameter, corrosion resistant fasteners furnished with oversized washers and located at no greater than eighteen (18) inches on center. A 2½” x 2" x 3/16" stiffener angle shall be bolted against the weir plate and through the trough to straighten and stiffen the trough edge.




O. Scum Baffles

1. A circular scum baffle shall be furnished and shall be supported at the knee braces and at the mid-section of the trough segments.

2. The scum baffles shall be fabricated of ¼-inch thick steel plate by a minimum of

twelve (12) inches deep. The scum baffle shall be positioned for a minimum of three (3) inches of freeboard from the design water surface.

3. The scum baffle shall be furnished in individual sections that are spliced by

vertical supports fabricated of steel and mounted to the ends of the knee braces. An adjustable Z-shaped brace fabricated of steel shapes shall support the mid-section of the baffle from the trough. Scum baffle supports shall be on a maximum five (5) foot centers and adjustable with a minimum ½-inch diameter fasteners. Each scum baffle section shall be attached to the supports with a minimum of six (6) ½-inch diameter round head carriage bolts providing a smooth surface for uninterrupted passage of the skimmer wiper.


P. Corrosion Protection

1. All fabricated steel components, hardware and items including the knee braces, trough sections, weir plates, splice bars, baffle supports, scum baffle sections and stiffening angles, etc., shall be hot-dip galvanized after fabrication. All items comprising the effluent trough assembly shall be detailed for field bolted assembly. No field welding will be allowed on hot-dip galvanized equipment.

2. All anchorage will be Type 304 stainless steel (if recommended by the

manufacturer for the clarifier materials of construction) and assembly fasteners used to assemble the effluent weir trough and baffle system shall be of Type A-325 carbon structural steel hot-dip galvanized and shall be a minimum of ½-inch diameter.

3. Anchors shall be of the drop-in type with one piece Type 304 stainless steel clip

or epoxy capsules.

Q. Lubrication

1. Lubricants of the type recommended by the equipment manufacturer shall be furnished and applied by the General Contractor.

2. The Contractor shall certify that the collector drive system has received the

proper amount of recommended lubricant.




3. EXECUTION 3.01 General

A. The clarifier equipment shall be furnished complete by the manufacturer and shall be assembled, erected and installed by the General Contractor as directed by the manufacturer in his working drawings and written instructions. The installation, alignment, testing and grouping shall be checked and approved by a factory representative before acceptance.

B. Installation shall include furnishing the required oil and grease for initial operation.

The grades of oil and grease shall be in accordance with the manufacturer's recommendations. Anchor bolts shall be set by the Contractor in accordance with the manufacturer's recommendations.

C. Supply all anchor bolts, temporary lift equipment, power, water, labor and all other

incidentals required for the proposed installation of the sump pump. D. The Contractor shall provide all required conduit and wire in support of the full and

complete installation of the secondary clarifiers including the lighting system. 3.02 Installation

A. The secondary clarification system shall be furnished complete by the manufacturer and shall be assembled, erected and installed by the Contractor in strict accordance with the manufacturer's written instructions, recommendations and erection drawings, by mechanics skilled in the installation of this type of work, in the location(s) shown on the Contract Drawings.

B. Erection drawings shall be submitted and approved prior to shipment of the

equipment. Mechanism parts shall be securely anchored to the concrete by stainless steel anchor bolts furnished by the manufacturer.

C. All necessary bolts, nuts, washers, hanger rods, clips, leveling nuts, tie-down nuts

and washers and other hardware items for anchoring and erection of the clarifier equipment shall be included in the Contractor’s Bid for this Project. The manufacturer shall ship anchor bolts, bolting template drawings, and accurate bolt setting pattern to the Contractor in advance of shipping fabricated items and other equipment. The Contractor shall not proceed with construction of the reactor-clarifier foundations and floor slabs until all anchor bolting materials, templates and patterns are received. The Contractor shall place all anchorage in exact accordance with the manufacturer’s certified dimension prints and as directed by the manufacturer.




D. Fabrication

1. All welds shall be continuous seal welds and shall be in accordance with current AWS Standards.

E. Clarifier Basin Flat Floor

1. The Contractor shall install a “flat” secondary clarifier floor to a tolerance of ±

1/16-inch of level from side to side and to ± 1/16-inch of flat across the surface with a smooth finish and no grouting will be required.

F. Lubrication

1. Lubricants of the type recommended and supplied by the equipment

manufacturer shall be furnished and applied by the Contractor.

2. The Contractor shall certify that the collector drive system has received the proper amount of recommended lubricant.

3.03 Torque Test

A. A torque test shall be conducted on the clarifier mechanism if deemed necessary by the Engineer.

B. The torque test shall be carried out by the Contractor under the supervision of the

field factory engineer employed by the manufacturer, before the mechanism is approved and placed into operation. The purpose of the test shall be to verify the structural integrity of the mechanism and sludge collector drive.

C. The torque test shall consist of securing the rake arms by cables to anchor bolts

installed by the Contractor in the tank floor at locations recommended by the clarifier equipment manufacturer. Readings shall be taken at fifty percent (50%), ninety percent (90%) and one hundred percent (100%) of design torque value.

D. The test load shall be applied such that the torque overload device can be used to

indicate and signal the alarm and motor cut-out torque values of the drives. A load shall be applied to the rake arm by means of a rachet lever and cylinder connected to the cable assembly. Loads shall not be applied by turning on the drive motor.

E. The field service representative shall certify that the alarm torques and motor cutout

torques of the overload control device, as calibrated, are proper to meet the requirements of this specification section.

F. All equipment required for the torque test shall be provided by the equipment

manufacturer. Upon completion of a successful torque test, the equipment shall be returned to the equipment manufacturer. The manufacturer shall, within five (5)




calendar days, provide the Engineer with a report documenting the torque test and the results.

3.04 Inspection and Testing

A. Manufacturer’s Services are presented in Article 1. 6 of this specification section. B. The field factory engineer shall inspect the completed installation for soundness,

completeness, correctness, alignment, arrangement, control settings and operation. C. Training of the Owner's personnel shall include instruction in proper operations and

maintenance procedures, start-up/shutdown procedures, response to emergency conditions, and troubleshooting.

D. The Contractor shall operate the clarifier mechanism for a minimum of seven

(7) consecutive days with the basins filled with water and check for binding, sticking or overloading of the motors and gear boxes. Continue restricting the collector arm movement until the shear pin overload device is sheared. Replace the shear pin. Operate the alarm system by restricting the collector arm movement. Test the motor according to Division 16, “Electrical”.

E. The Contractor shall ensure that all secondary clarifier functions (alarms, etc.) are

operating properly and being picked up by the facility-side SCADA system.

END OF SECTION
