SECTION RETRIEVABLE FINE BUBBLE DIFFUSER SYSTEMS

Transcription

1 SECTION RETRIEVABLE FINE BUBBLE DIFFUSER SYSTEMS PART 1 GENERAL 1.1 SECTION INCLUDES This section includes the design, manufacture, installation and start-up requirements for the fine bubble diffuser systems to be installed at the three wastewater treatment plants 0fVWTPs) in the project, as shown on the Drawings and as specified herein. A. Scope of Work under this section: The principal components of the diffuser systems shall include, but not be limited to, the following: 1. Removal of obsolete components of existing aeration system, 2. Replacement Air Header Piping, Header Stubs and Air Lateral Piping, 3. Isolation/Balancing valves in Header Stubs, 4. Retrievable in-basin Aeration Grids with ballasts, 5. Flexible membrane fine bubble tube style Diffuser Assemblies, 6. Connection devices, hardware, and all appurtenances, 7. Installation, including minor modifications of existing plant components to facilitate installation, 8. Startup of the system, 9. Provide waste management records for any sanitary or hazardous waste. All aeration system equipment furnished shall be of the same manufacturer, except that the ballasts may be provided by a separate supplier. All components, with the exception of the diffuser membranes, shall be consistent with a 20-year service life for the installation. The new Air Header Piping shall be connected to and compatible with the existing Blower Manifold Piping and the Header Stubs shall be connected to and compatible with the Air Lateral Piping. 1.2 RELATED SECTIONS A. Section Submittals B. Section Quality Control C. Section Materials and Equipment D. Section Contract Closeout 1.3 REFERENCES: Publications by the following agencies or associations form a part of these specifications to the extent indicated by references thereto. The latest revisions of these publications in effect at the time of bid opening shall be applicable. BCRSD Energy Efficiency Improvements at Three WWTPs SKW

2 A. American Iron and Steel Institute (AISI) 1. AISI AISI304L Stainless Steel Stainless Steel B. American National Standards Institute (ANSI): 1. B B17.1 Cast Iron Pipe Flanges and Flanged Fittings Keys and Keyseats C. American Society for Testing and Materials (ASTM): 1. A48 Gray Iron Castings 2. A240 Stainless Steel 3. A307 Carbon Steel Externally and Internally Threaded Standard Fasteners 4. D3350 Polyethylene Plastics Pipe and Fittings Materials 5. F714 Polyethylene (PE) Plastic Pipe D. Hydraulic Institute Standards (HIS) 1.4 DEFINITIONS: A. Aeration Grid: Associated piping and diffuser components connected to a single Air Drop Pipe. Includes Air Manifold Piping, Air Header Distribution Piping and Diffuser Assemblies. B. Air Distribution Uniformity: Variation in air distribution between Diffuser Assemblies. C. Air Drop Pipe: Vertical piping section from out-of-basin Header Stub to inbasin aeration system. D. Air Header Distribution Piping: Air distribution piping from Air Manifold Piping to Diffuser Assemblies. E. Air Header Piping: Out-of-basin air distribution piping from the Blower Manifold Piping to the Header Stubs. F. Air Lateral Piping: Air distribution piping from the Header Stub to the Diffuser Assembly. Includes Air Drop Pipe, Air Manifold Piping and Air Header Distribution Piping. G. Air Manifold Piping: Air distribution piping from the Air Drop Pipe to the Air Header Distribution Piping. H. Blower Manifold Piping: Air distribution piping between the blower discharge and Air Header Piping. I. Diffuser Assembly: Fabricated assembly including multiple Diffuser Units, hub assembly, and assembly mounting components. Also includes ballast components, where applicable. J. Diffuser Unit: Fabricated unit including diffuser support frame and flexible membrane which releases air into the water. BCRSD- Energy Efficiency Improvements at Three WWTPs SKW

3 K. Header Stub: Air distribution piping from the Air Header Piping to the Air Lateral Piping. Header Stub shall extend into the tank, above the water surface, and terminate with a vertical face, full diameter, flanged connection. L. Isolation/Balancing Valve: Manual ball valve located between the Air Header Piping and Air Lateral Piping. Valve provides control of air release to the Air Lateral Piping for system balancing as well as isolation capability for maintenance operations. M. Maximum Pressure: Pressure in Blower Manifold Piping at the specified airflow rate. N. Oxygen Transfer Efficiency: Percent of oxygen in the air stream that is dissolved to the wastewater under specified conditions of temperature, barometric pressure, airflow rate, and dissolved oxygen concentration. 0. Standard Cubic Feet per Minute (scfm): Air at 68 F, 14.7 psia and 36% relative humidity. P. Standard Oxygen Transfer Efficiency (SOTE): Percent of oxygen in the air stream that is dissolved to clean water under conditions of 68 F, 14.7 psia, and zero dissolved oxygen. Q. Tank: Vertical walled reactor within which aeration occurs. 1.5 COMMON DESIGN PARAMETERS: This paragraph is applicable to all WWTPs - in addition to the requirements of Paragraph 1.6. A. BODs in wastewater inflow to treatment tank: 250 mg/1 B. Ammonia in wastewater inflow to treatment tank: 35.0 mg/1 C. Design BODs removal: 100% D. Minimum dissolved oxygen level in treatment tank: 2.00 mg/1 E. Temperature of wastewater, winter: 10.0 C F. Temperature of wastewater, summer: 25.0 C G. Site elevation above sea level: 700ft H. Alpha, ratio of oxygen transfer in wastewater to transfer in tap water: 0.60 Alpha I. Beta, ratio of solubility of oxygen in wastewater to solubility in tap water: 0.95 Beta J. Theta, temperature correction factor: K. Design diffuser air fluxrate for aeration tanks shall be based on the larger of the oxygenation and mixing requirements. 1.6 INDIVIDUAL DESIGN PARAMETERS: This paragraph is applicable to individual WWTPs - in addition to the requirements of Paragraph 1.5. A. For drawings of existing systems refer to the plans. B. All parameters are to be Contractor verified for each proposed aeration system. C. Design parameters for individual WWTPs: BCRSD -Energy Efficiency Improvements at Three WWTPs SKW

4 ! WWTP Design Flow Current Flow Tank Depth Side Water Tank floor (mgd) (mgd) (ft) Depth (ft) Area (fe) Midway Crossings- Treatment Tank Midway Crossings- Sludge Holding Tank! , Prairie Meadows South Rt K i ,980! 1.7 SUBMITTALS: The Contractor shall submit the following in accordance with Section Submittals and Section Contract Closeout. The submittal package shall be provided in sufficient detail and scope to confirm compliance with the requirements of this section. Submittals shall be complete for all required components. Partial submittals will not be accepted. A complete and separate submittal package shall be provided for each WWTP in the project. A. Product Data for Review: 1. Diffuser system material specifications and weights. 2. Diffuser system dimensional data. 3. Diffuser system support dimensions and material specifications. 4. Diffuser system ballast specifications, weights, and dimensions, including attachments. B. System Design Data for Review: 1. Provide data for design flows and current flows. 2. Certified Oxygen Transfer Performance Curve, prepared and sealed by a professional engineer: Oxygen transfer efficiency in percent versus air fluxrate defined as psia, 20 C and zero dissolved oxygen at each specified submergence. 3. Oxygen transfer performance in wastewater at design conditions. 4. Complete air headless calculations for the aeration equipment from the top of the Air Drop Pipe to the farthest diffuser bubble release point. 5. Manufacturer's design calculations showing uniform air distribution (+1 0% maximum variation) through Air Lateral Piping and diffuser element orifice system, including operating pressure (psi) as a function of airflow rate (scfm/ft 2 ) and required blower brake horsepower. 6. Design calculations for piping and support components. C. System Performance Data for Review: 1. Quality Assurance Testing: a. The membrane diffusers shall be sampled and tested for air distribution uniformity, dynamic wet pressure, and dimensional tolerances. BCRSD- Energy Efficiency Improvements at Three WWTPs SKW

5 b. Test samples shall be selected from the membrane lots to be used on the project. A minimum of 1% random samples shall be selected from each lot. c. Sampling and testing information shall be supplied by the manufacturer. d. Dynamic wet pressure and dimensional tolerance test samples shall be drawn from the sample lot selected for uniformity testing. e. Test diffuser elements for dynamic wet pressure (DWP) by submerging a diffuser unit at least two inches in tap water and operate at an air rate of 5 scfm per square foot ±1 0%. DWP values shall be within ±1 0% of average value. DWP is defined as the pressure to operate at the specified conditions minus submergence and flow control losses. f. Dimensional Tolerances, divergence from design value: i. Membrane Thickness: 2 mm ±0.2 mm ii. Membrane Inside Design Diameter: ±1.0 mm iii. Membrane Design Length: ±5 mm 2. Endurance Testing: Certified endurance test data shall be supplied for the diffuser units proposed in accordance with the following test conditions: a. Operate diffuser unit while submerged 12 inches in clean water through at least 1 million on/off cycles. b. Cycles shall be at least 10 second duration. c. Membranes shall retain initial headless, dimensional tolerances, SOTE, and visual characteristics. D. Shop Drawings for Review: Detailed layout drawings for aeration system components shall include: 1. Layout and configuration of aeration system. 2. Detail drawings of Diffuser Assemblies showing components, method of construction and attachment mechanism to Air Header Distribution Piping. 3. Detail drawings of Air Lateral Piping showing inlet, outlet, and terminal end connections. 4. Detail drawings of Header Stub components. 5. Detail drawings of Isolation/Balancing valves 6. Detail drawings of all inter-piping and valve connections and inline connections for all piping. 7. Detail drawings of piping restraint components. 8. Detail drawings of pipe support components. 9. Detail drawings of ballasts and their attachments to Air Header Distribution Piping. BCRSD Energy Efficiency Improvements at Three WWTPs SKW

6 E. Installation Instructions: 1. Manufacturer's Instructions for installation and guidelines for all proposed diffuser system components. 2. Information on the aeration system shall include, but not be limited to: a. Diffuser unit assembly. b. Diffuser Assembly attachment. c. Piping components and assembly. d. Piping support components. e. Air Lateral restraint components. f. Retrieval components. g. Fusion welding guidelines, where applicable. F. Operation and Maintenance Data: Submit Operation and Maintenance Instructions providing complete information on operation and maintenance for the diffuser systems, as specified herein. 1. The Contractor shall provide at least three (3) copies of instruction books for all aeration equipment and accessories furnished. ALL INSTRUCTION BOOKS MUST BE DELIVERED TO THE OWNER AT LEAST TWO WEEKS PRIOR TO THE SERVICE TRAINING. Instruction books shall be prepared by the equipment supplier with loose-leaf pages mounted in durable covers and include the following: 2. Operations and maintenance data for all proposed equipment. 3. Information on the system shall include, but not be limited to: a. Index and tabs. b. Data sheets showing model numbers of equipment and additional data as required to identify equipment used. c. Instructions for storage, handling, installation, startup, operation, inspection, and maintenance, including Diffuser Assembly maintenance and membrane replacement. d. Applicable drawings, corrected to shown field changes. Drawings indicating field changes to be provided after installation is complete, including Lateral restraint system. e. Air flow balancing. f. Troubleshooting guide. g. Parts list and recommended spare parts. h. Address and contact information of nearest manufacturerauthorized service facility. i. All additional data specified. G. Supplier's written warranty: Warranty shall not be prorated. The membranes shall have a minimum warranty period of five (5) years. All equipment and workmanship furnished under this section shall be guaranteed to be free of defects in materials and workmanship for a period of twelve (12) months from the date of each installed system SKW

7 passing acceptance testing, with a passing test being determined by the sole opinion of the Owner's Representative. Any such defects which occur within the stipulated guarantee period, shall be repaired, replaced or made good at no cost to the Owner. The occurrence of any such defects within the warranty period shall restart the warranty period with the new period start date being the date of such resolution of the defect to the Owner's satisfaction. PART2 PRODUCTS 2.1 GENERAL A. In-basin air p1p1ng and diffusers to diffuse air throughout the aeration tank(s) in accordance with the specifications. B. Each diffuser assembly shall provide uniform air release over the specified airflow range. C. The aeration system shall provide at least the minimum specified oxygen transfer efficiency at the specified airflow and operating pressure. D. The aeration system shall be fully retrievable without the need to take the basin off-line. 2.2 ACCEPTABLE MANUFACTURERS: A. Environmental Dynamics Inc., Columbia, Missouri. B. Red Valve Company, Inc. C. Engineer approved equal. 2.3 MATERIALS: Materials for all parts of the diffuser system shall conform to the publications and other requirements referenced in the specifications and called out on the drawings. A. Welded Stainless Steel Components: 1. Sheets and plates of Type 304L stainless steel with 2D finish conforming to AISI 304L and ASTM A Limit carbon content to 0.30% maximum. B. Non-welded Stainless Steel Components: Sheets and plates of Type 304 stainless steel conforming to AISI 304 and ASTM A240. C Fasteners and Anchorage Components: 18-8 series stainless steel. D. PVC Pipe and Fittings (Schedule 40 and 80): 1. Base material shall be ASTM D SKW

8 2. Pipe shall be manufactured in accordance with ASTM D-1785 and ASTM D E. PE Pipe and Fittings: 1. Base material shall be PE 3408, ASTM D-3350, PE C. 2. Pipe shall be manufactured in accordance with ASTM F AERATION EQUIPMENT: - This paragraph is applicable to all WWTPs - in addition to the requirements of Paragraph 2.5. A Flexible Membrane Fine Pore Diffusers: 1. The diffuser membrane shall be held in place by two crimp type 304 stainless retainer clamps. Worm gear type clamps are not acceptable. 2. Installation of the diffuser membrane shall be accomplished with the removal and installation of the membrane clamps. Disassembly of Diffuser Assembly to remove and install membranes is not acceptable. 3. Individual Diffuser Units shall be provided with an internal end cap. 4. The diffuser unit shall be fully capable of operating under continuous or intermittent conditions and shall be designed with check valve capabilities to prevent entry of mixed liquor into the Diffuser Unit or air piping on air shutdown or interruption of air supply. A minimum of three (3) check valve features shall be provided, including, but not limited to the following: a. Membrane shall be elastic and allow openings to close when the air supply is interrupted. b. Membrane shall contract and close around full diameter support frame. c. Membrane shall employ a non-perforated section that is aligned with and seals against the support frame air distribution orifices. d. Use of independent or internal check valve in lieu of any of the above components is not acceptable. 5. Diffuser Assemblies shall be completely factory assembled with Diffuser units, membranes and mounting saddle factory installed. Field solvent welding or assembly of diffuser is not acceptable. 6. Diffuser assemblies shall be shipped to the jobsite properly crated and protected for shipment and handling. 7. All metal components used in the aeration-mixing assemblies or accessories shall be 304 stainless steel. a. Stainless steel components shall include anchor bolts, straps, eye anchors, membrane retainer clamps, fasteners, and miscellaneous components. b. Galvanized metal or carbon steel is not acceptable, including use for ballast or ballast components. SKW

9 B. Flexible Membrane Material: 1. Membrane material for the diffuser unit shall be polyurethane. Alternate membrane materials are only acceptable with Engineer's prior approval. 2. Membrane shall be extruded in a single piece with the following characteristics. a. Membrane shall have an inside diameter and overall length as sized by the manufacturer for most economical, efficient and serviceable performance of the wastewater treatment system. b. Perforated length on diffuser membrane shall extend over at least 95% of the length of the membrane. c. Membrane shall be perforated on the top of the sleeve. d. Non-perforated membrane section shall be provided to seal off air distribution orifices on the diffuser support structure. C. The aeration system components following the Header Stubs, including the Air Drop Pipes and Aeration Grids, shall be sized by the system manufacturer in compliance with the requirements of this Section. D. Aeration System Piping: 1. Out-of-basin air piping, including Air Header Piping and Header Stubs are required and are to be supplied by the Contractor. 2. Air Header Piping shall be sized to match existing and connected to the Blower Manifold Piping. 3. Header Stubs shall extend to the inside top of the wall and terminate near the waterline with a full diameter vertical face flange. 4. Out-of-basin piping may be unlined ductile iron, galvanized steel, stainless steel, or painted carbon steel. 5. The Contractor shall provide an isolating/balancing valve on each Header Stub for control and distribution of air to the aeration grid and to allow isolation of the grid for inspection and/or maintenance. 6. Isolation/balancing valve shall be positioned for accessibility from the top of the tank and be located above the waterline. E. Isolation/Balancing Valves: 100% full port quarter-turn ball valve to turn air on/off or adjust airflow. Valve shall have two NPT female threaded connections. Handle shall be steel with vinyl covering. Valves shall have brass body, brass stem and chrome-plated brass ball. Seats and seal shall be Teflon. High capacity airflow design shall reduce pressure drop. Valve shall be designed for water and air in commercial and light industrial use. 1. Tested to MIL-STD-105E. 2. UL listed 3. Blow-out proof, 4. Maximum pressure rating: 600WOG. SKW

10 5. Temperature range: -20oF to +300oF 6. Large raised wrench flats 7. Rugged forged construction F. Spare Parts: 1. The Contractor shall furnish the following spare parts for each WWTP and store as directed by the Owner: a. Five (5) completely factory assembled Diffuser Assemblies, including membrane sleeves and stainless steel membrane clamps of the same model as installed at the WWTP. G. Aeration System Definitions: 1. Active Surface Area: Is defined as the net perforated area of the media or membrane. The term reflects only that portion of the membrane which can be demonstrated to produce uniform air discharge under the full operating range proposed for the diffuser. 2. AOR: Actual oxygen requirement needed to meet field conditions. 3. DWP: Dynamic wet pressure, pressure to operate at the specified conditions minus submergence and flow control losses. 4. SCFM: Standard cubic feet per minute. 5. SOR: Standard oxygen requirements for clean water at 20 C and sea level air pressures. 2.5 AERATION EQUIPMENT: - This paragraph is applicable to individual WWTPs - in addition to the requirements of Paragraph 2.4. A. All parameters are to be verified by manufacturer of diffuser system and adjusted as needed. Any adjustments are to be submitted to Engineer for approval. B. System Performance for Midway Crossings WWTP - Treatment Tank: 1. The aeration-mixing system shall be designed to meet the following: a. AOR: 26.6 lb/0 2 /hr b. SOTE: 24.1 % c. Airflow: 241 scfm d. Blower discharge Pressure: 9.6 psig e. Diffuser Unit DWP: 10.0 in H 2 0 maximum f. Design Diffuser Submergence: 11.5 ft maximum 2. The diffusers shall be designed to meet the following: a. Air Fluxrate for active diffuser surface area at the design airflow: 1.09 scfm/ft2. b. Total Active Surface Area: 222 ft2 minimum BCRSD Energy Efficiency Improvements at Three WWTPs SKW

11 C. System Performance for Midway Crossings WWTP - Sludge Holding Tank: 1. The aeration-mixing system shall be designed to meet the following mixing requirements: a. Airflow: 210 scfm minimum, as required for mixing b. Blower discharge Pressure: 9.6 psig c. Design Diffuser Submergence: variable, 11.5 ft maximum 2. The diffusers shall be designed to meet the following: a. Air Fluxrate for active diffuser surface area at the design airflow (scfm!ft 2 >. Per manufacturer b. Total Active Surface Area: Per manufacturer D. System Performance for Prairie Meadows WWTP: 1. The aeration-mixing system shall be designed to meet the following: a. AOR: 14.2 lb/oz/hr b. SOTE: 16.7% c. Airflow: 188 scfm d. Blower discharge Pressure: 6.2 psig e. Diffuser Unit DWP: 12.0 in H 2 0 maximum f. Design Diffuser Submergence: 8.50 feet maximum 2. The diffusers shall be designed to meet the following: a. Air Fluxrate for active diffuser surface area at the design airflow: 2.37 scfm/ft2. b. Total Active Surface Area: 79 ft2 minimum E. System Performance for South Route K WWTP: 1. The aeration-mixing system shall be designed to meet the following: a. AOR: 24.8 lb/oz/hr b. SOTE: 19.0% c. Airflow: 288 scfm d. Blower discharge Pressure: 9.8 psig e. Diffuser Unit DWP: 10.5 in H 2 0 maximum f. Design Diffuser Submergence: 9.00 feet maximum 2. The diffusers shall be designed to meet the following: a. Air Fluxrate for active diffuser surface area at the design airflow: 1.21 scfm/ft2. b. Total Active Surface Area: 238 ft 2 minimum F. Flexible Membrane Fine Pore Diffusers for Midway Crossings WWTP Treatment Tank: 1. The Diffuser Assemblies shall be sized, furnished and installed. BCRSD Energy Efficiency Improvements at Three WWTPs SKW

12 2. Each Diffuser Assembly shall be factory assembled and include two diffuser units and mounting saddle. 3. Diffusers Unit shall have nominal dimensions of 4.5 inches in diameter and 53.5 inches long. 4. The diffuser membrane shall be fully supported over the full length and circumference with a 4.5 inch PVC membrane support frame. Use of a non-fully supported diffuser membrane is not acceptable. 5. The diffuser support frame shall be approximately 53.5 inches long and have a full diameter mbunting connection. Use of non-full diameter mechanical connections, including threaded connections, is not acceptable. 6. Diffuser saddle mount shall be schedule 80 PVC construction and shall be capable of withstanding an external force of 4,800 inchpounds without structural failure of the air distribution piping, diffuser unit connections or mounting saddle. a. Small diameter threaded connections to attach diffusers to the air distribution header are not acceptable. 7. Saddle mount shall fully encompass the Air Distribution Header and reinforce the pipe section at the Diffuser Assembly connection. 8. An 0-ring gasket shall be provided to ensure an air tight seal between the mounting saddle and Air Distribution Header. 9. A minimum 3 inch diameter connection shall be provided between the saddle mount and Diffuser Assembly. 10. The Diffuser Assembly shall mount below the Air Distribution Header piping and provide full evacuation of entrapped water from the header through the Diffuser Assemblies. Systems that do not automatically purge entrapped water are not acceptable. G. Flexible Membrane Fine Pore Diffusers for Midway Crossings WWTP Sludge Holding Tank: 1. The Diffuser Assembly shall be sized, furnished and installed. 2. Each Diffuser Assembly shall be factory assembled and include two diffuser units and mounting saddle. 3. Diffusers unit shall have nominal dimensions of 3.5 inches in diameter and be 20 inches long. 4. The diffuser membrane shall be fully supported over the full length and circumference with a 3.5 inch PVC membrane support frame. Use of a non-fully supported diffuser membrane is not acceptable. 5. The diffuser support frame shall be approximately 20 inches long and have a full diameter mounting connection. Use of non-full diameter mechanical connections including threaded connections is not acceptable. 6. Diffuser saddle mount shall be schedule 80 PVC construction and shall be capable of withstanding an external force of 4,800 inchpounds without structural failure of the air distribution piping, diffuser unit connections or mounting saddle. a. Small diameter threaded connections to attach diffusers to the air distribution header are not acceptable. SKW

13 7. Saddle mount shall fully encompass the Air Distribution Header and reinforce the pipe section at the Diffuser Assembly connection. 8. An 0-ring gasket shall be provided to ensure an air tight seal between the mounting saddle and Air Distribution Header. 9. A minimum 3 inch diameter connection shall be provided between the saddle mount and Diffuser Assembly. 10. The Diffuser Assembly shall mount below the Air Distribution Header piping and provide full evacuation of entrapped water from the header through the Diffuser Assemblies. Systems that do not automatically purge entrapped water are not acceptable. H. Flexible Membrane Fine Pore Diffusers for Prairie Meadows and South Route K WWTPs: 1. Diffusers Units shall have nominal dimensions of 4.5 inches in diameter and 40 inches long. 2. Diffuser Assembly with two Diffuser Units per assembly shall be employed over the flat floor area of the reactor. 3. The diffuser membrane shall be fully supported over full length and circumference with a 4 inch PVC membrane support frame. Use of a non-fully supported diffuser membrane is not acceptable. 4. The diffuser support frame shall be approximately 40 inches long and have a full diameter mounting connection. Use of non-full diameter mechanical connections, including threaded connections, is not acceptable. 5. Diffuser Assemblies shall be configured such that the assembly contacts the basin floor and shall allow individual assemblies to be retrieved and raised to the tank surface for inspection and/or maintenance. a. Assembly retrieval shall be possible without lowering the liquid level of the basin, without taking the basin out of service, and without disturbing or impairing operation of other aspects of the treatment process or other diffuser units. b. Assembly shall be retrievable by a single retrieval harness. A requirement for multiple harnesses shall not be acceptable. 6. Each Diffuser Assemblies shall be ballasted using submerged concrete supplied by the Contractor in the field. The ballast units shall have a submerged weight sufficient to offset any buoyant forces under all conditions of operation. a. Concrete ballast shall be furnished and installed in accordance with the aerator unit manufacturer's instructions using maximum aggregate size of 3/4 inch. b. Ballast forms provided by the manufacturer shall be of proper geometry to assure stability of the assembly when in operation. c. The ballast form shall be designed to protect fabric or plastic liner. SKW

14 d. Embedded ballast anchor components shall be unitized as a single assembly. Anchorage assembly shall be fabricated with spacers to properly position the assembly in the ballast form. e. Requirement for more than one ballast assembly per diffuser assembly is not acceptable. I. Flexible Membrane for Midway Crossings WWTP Treatment Tank: 1. Membrane shall be 117 mm inside diameter with an overall length of 1,359 mm. 2. Perforated length on diffuser membrane shall be 1,308 mm. 3. Membrane shall be perforated on the top half of the sleeve. J. Flexible Membrane for Midway Crossings WWTP Sludge Holding Tank: 1. Membrane shall be 94 mm inside diameter with an overall length of 500 mm. 2. Perforated length on diffuser membrane shall be 462 mm. 3. Membrane shall have a 20 mm perforated strip at the top and bottom of the diffuser to reduce bubble coalescence. K. Flexible Membrane for Prairie Meadows and South Route K WWTPs: 1. Membrane shall be 117 mm inside diameter with an overall length of 1,000 mm. 2. Perforated length on diffuser membrane shall be 924 mm. 3. Membrane shall be perforated on the top half of the sleeve. L. Aeration System Out-of-Basin Piping for Midway Crossings WWTP: 1. Material of Air Header Piping, Header Stub and Fittings: Hot-dipped galvanized steel, except that Air Header tees may be coated steel. Connections shall be Victaulic style couplings. 2. Number of Header Stubs for aeration tank: three (3) 3. Number of Header Stubs for sludge tank: one (1) 4. Location of Header Stubs: Centered between crossbeams. M. Aeration System Out-of-Basin Piping for Prairie Meadows WWTP: 1. Material of Air Header Piping, Header Stub and Fittings: Hot-dipped galvanized steel, except that Air Header tees may be coated steel. Connections shall be Victaulic style couplings. 2. Air Header shall be routed under walkway to longitudinal centerline of treatment tank and mounted to underside of each crossbeam. 3. Air Header mounts shall consist of galvanized steel pipe hangers. 4. Number of Header Stubs: ten (1 0) 5. Location of Header Stubs: Centered between crossbeams. BCRSD- Energy Efficiency Improvements at Three WWTPs SKW

15 N. Aeration System Piping Out-of-Basin for South Route K WWTP: 1. Material of Air Header Piping, Header Stub and Fittings: Hot-dipped galvanized steel, except that Air Header tees may be coated steel. Connections shall be Victaulic style couplings. 2. One Air Header shall be installed for each aeration tank. 3. Air Headers shall be routed along the outside of each treatment tank and mounted six (6) inches above finished ground. 4. Air Header mounts shall consist of galvanized pipe stands which are mounted into the soil adjacent to each tank. 5. Number of Header Stubs for each tank: fifteen (15) 6. Location of Header Stubs: Centered between crossbeams. 0. Submerged Air Lateral Piping and Support Structure for Midway Crossings WWTP, Both Tanks: 1. A complete retrievable fine bubble diffused aeration system shall be furnished and installed by the Contractor. 2. The Diffuser Assemblies shall be mounted directly on the Air Manifold Piping. Air Distribution Piping shall not be required. 3. The aeration equipment manufacturer shall size the Header Stubs. 4. The aeration equipment manufacturer shall size and furnish the equipment in each aeration basin beginning with the Air Drop Pipes. a. The Air Drop Pipes shall consist of flexible discharge hose with tube and cover comprised of black EPDM. The flexible hose shall have a minimum temperature rating of 170 F and a maximum pressure rating of at least 70 psig. Multiple textile plies shall be provided for hose reinforcement. b. Flanged insert fittings shall be used to connect the flexible inlet hose to the metal Header Stub. Fittings shall be made of 304 stainless steel and shall have a standard 150# flange connection. c. Flexible hose shall be attached to stainless steel insert fittings via double bolt clamps or stainless steel retainer clamps. d. Standard 18-8 stainless steel flange bolts and fasteners shall be used for the flexible inlet hose connections. e. The flexible inlet hose shall be factory assembled and supplied for installation onto the Aeration Grid assembly. 5. The Air Manifold Piping shall be 304 stainless steel schedule 40, sized by the manufacturer. At the inlet end of the manifold pipe there shall be a factory welded stainless steel hose insert. The hose insert shall incorporate three factory welded hose retainer rings. The EPDM flexible inlet hose shall be fitted over the hose insert and secured with three double bolt clamps. At the opposite end of the Air Manifold Pipe there shall be a welded stainless steel end cap. SKW

16 6. At each end of each Air Manifold Pipe, there shall be a W-type galvanized support beam/concrete ballast beam. Each support beam shall be secured to the manifold using 304 stainless steel straps that utilize dielectric isolation in order to prevent galvanic corrosion between dissimilar materials. The manifold and two support beams shall be designed to deliver a net negative buoyancy of twice (2x) the operating buoyancy under normal operating conditions. 7. The 304 stainless steel retrieval cable shall be attached to each support beam and at an easily accessible location near the top of the tank. The aeration equipment manufacturer shall supply cable, thimbles and wire rope nuts. 8. Items provided by the equipment manufacturer shall include, but not be limited to: Inlet flange, EPDM flexible hose, inlet hose insert, stainless steel Air Manifold Piping and supports, retrieval cable, Diffuser Assemblies and airflow control orifices. a. Use of non-reinforced diffuser connections, such as threaded diffuser mounts and/or outlets, are not acceptable. b. The saddle outlet and diffusers shall be located at the bottom of the Air Manifold Piping to allow full drainage of liquid and solids for automatic purge without the need or use of independent water purge assemblies. P. Floating Laterals Aeration System Piping for Prairie Meadows and South Route K WWTPs: 1. In-basin air p1p1ng consisting of floating Air Lateral Piping shall transition from the Header Stub and extend across the aerated portion of the reactor. a. Lateral piping shall be heavy-walled, high density polyethylene (HOPE). b. Lateral piping shall be sized to allow a normal airflow variation of 0 to 200% of the designed airflow. c. Inlet connection shall be a full diameter flange fitting. d. Six (6) inch laterals shall be provided. i. SDR-21 minimum shall be used for the lateral piping. ii. All fittings, flange adapters and the initial 10 feet of the lateral run shall be SDR-11 minimum. iii. Lateral piping shall be butt fusion welded in the field by the Contractor to assure maximum strength and structural integrity, except that fusion welds between pipe sections with different wall thickness shall be completed at the factory. Field fusion welding of these sections shall not be allowed. iv. Lateral piping shall be shipped to the jobsite in up to 40 feet lengths. v. Lateral sections with a diffuser assembly spacing less than 20 feet shall be shipped with outlet tees factory SKW

17 installed. Installation of these sections requires butt fusion welding adjoining sections. vi. Laterals sections with a Diffuser Assembly spacing greater than 20 feet shall be shipped in straight lengths. Outlet tees shall be side fusion welded to a 2 foot section of lateral pipe and shipped loose. Installation requires butt fusion welding outlet tee lateral sections into the lateral piping at the required locations. e. Each diffuser assembly shall receive air from the floating polyethylene lateral from a flexible EPDM airline, sized by the manufacturer. i. This EPDM airline shall be sized to provide complete coverage of the aeration system and sized by the manufacturer. ii. Airline shall be reinforced with a minimum of four (4) spirals of polyester cord. iii. Minimum working pressure for the airline shall be 150 psig. f. An outlet tee shall be provided on the lateral section to transition to the Diffuser Assembly airline. i. Outlet tee shall be HOPE construction and shall be an ii. equivalent diameter to the airline. Outlet tee shall be side fusion welded to the lateral pipe section. A weld contact area equal to 4 square inches minimum is required. g. All side fusion welding shall be completed in the factory. Field side fusion welding is not acceptable. h. The use of mechanical fittings in lieu of a fusion-welded outlet is not acceptable. 2. Floating laterals shall be restrained in place by means of an end tether. a. Lateral piping shall terminate with a HOPE end cap, welded at the factory. b. Tether rope shall be attached to the lateral via stainless steel compression clamp and wire rope nuts. c. Tether rope shall be UV resistant, double-braid polyester. d. Tether rope shall be anchored to the side of the tank. 3. Systems that are not fully restrained and allow random movement of laterals are not acceptable. 2.5 PAINTING: All stainless steel, aluminum and hot-dipped galvanized surfaces shall be left unpainted unless specified otherwise. All iron or steel surfaces shall be painted and prepared first by removing all mill scale, rust or other deleterious material and thoroughly cleaning with solvent. The coating system shall be of a lead free epoxy type and shall consist of prime coat plus at least one top coat. Total thickness of coating system shall be 10 mils minimum unless otherwise recommended by the coating manufacturer. Machined surfaces which are not to BCRSD- Energy Efficiency Improvements at Three WWTPs SKW

18 be painted and which are shipped unassembled to a mating surface shall be coated with rust preventive compounds: PART3 EXECUTION 3.1 INSTALLATION: A. Contractor shall save all obsolete diffusers, piping, valves, couplings, etc. that are practical to salvage and store on site for the Owner. B. Contractor shall furnish, inspect, store, and install aeration system and ancillary components in accordance with manufacturer's written instructions and approved submittals. C. Air Header Piping shall be replaced along current alignment and use existing mounts where practical, unless otherwise specified. Any airlifts shall be reconnected and tested for functionality all necessary adjustments shall be made to restore functionality of airlifts. D. Isolation/Balancing valves shall be installed in the Header Stubs, near the tee connection to the Air Header Piping. The valves shall be installed above the waterline with the handle pointing upwards in the fully open position. Valves shall be easily accessible for adjustments and maintenance, without the removal of any grating or other treatment system components. E. Cutting of any grating to facilitate aeration system installation shall be kept to a minimum and coordinated with the Owner's representative. In no case shall any modification to any grating compromise any safety requirements or features, including those related to load capacity and stability of the walking and working surface. Any cut surfaces in galvanized grating shall be re-galvanized for lasting corrosion protection. F. Diffuser Assemblies on a common grid shall be installed within an elevation tolerance of ±1/2 inches. G. All floor supports shall be fully supported by the floor of the tank, rather than any foreign substances or objects, including but not limited to grit or sludge. H. Contractor shall provide and adjust all valves, piping, wall sleeves with seals, wall pipes, pipe supports, and concrete ballasts as necessary to complete the system as sp~cified and shown on the plans. I. All air piping and Diffuser Assemblies must be completely clean internally prior to delivering air to the diffusers. SKW

19 J. Contractor shall be responsible for cleanliness of piping and diffusers and may be required to manually clean pipe or air or water flush piping, as required. 3.2 STARTUP A. After installation is completed, the Contractor shall perform the following field tests in the presence of the Engineer, manufacturer's field representative and the Owner. Any water, air, power, and labor associated with testing and adjustment of diffuser assemblies are to be supplied by Contractor. The field test shall be modified, as required, if dewatering was not performed. 1. Fill the reactor to the bottom of the diffuser assemblies. 2. Adjust the pipe supports and diffuser assemblies such that all diffuser units are installed within ±1/2 inches of the design diffuser elevation. 3. Fill the reactor to a level of 2 feet above the top of the diffusers. 4. Release air to the system and inspect the system for air leaks at all piping or diffuser connections. 5. Check all membranes for cuts and/or tears, including those that may have occurred during the installation. 6. Adjust any piping or diffusers that show leaks or disproportionate amount of airflow. 7. Repeat any steps, as needed, to ensure performance as designed and complete functionality of the diffuser grit. 8. The above steps constitute Preliminary Testing. 9. Fill the tank to the normal operating water level. 10. Operate the blowers at the design air rate and observe air release and air distribution patterns. 11. Repeat any steps, as needed, to ensure performance as designed and complete functionality of the system. 12. In order for the fine bubble system to pass field testing, all air leaks or blockages must be eliminated and a uniform distribution pattern must be achieved over the entire tank volume for the range of conditions expected under normal operation and for the various flows normally found in each system. 3.3 MANUFACTURER'S FIELD SERVICES A. Either the manufacturer shall perform the installation or a manufacturer's representative shall be present at the job site to continuously supervise and inspect the installation of the equipment. B. A manufacturer's representative shall start up the system in the presence of the Owner's representative. C. The Contractor shall provide a qualified manufacturer's service person for complete instructional training for the Owner's operating and maintenance BCRSD -Energy Efficiency Improvements at Three WWTPs SKW

20 personnel after the system is fully operational. Training shall include onsite instruction and demonstration of detailed procedures for the assembly and disassembly of aeration system components, trouble shooting procedures, recommendations for routine inspections, and preventive maintenance procedures. D. Manufacturer's startup and training services shall including a minimum of one (1) trip to the job site with a total of one (1) eight (8)-hour working day on site. Additional trips and time shall be provided, as needed, to provide a fully functional system meeting the design requirements. Additional trips shall be provided by the manufacturer and Contractor at no additional cost to the Owner. E. A manufacturer's representative shall be available for on-site service calls within a 24-hour notification period. END OF SECTION BCRSD- Energy Efficiency Improvements at Three WWTPs SKW

21 H. BLOWER MANIFOLD PIPING /~~~~w~~>y>k/. v y' K. HEADER STUB $' X X (, ~ X 'v <:) 0-0<:) c,v ~ ~' ~ - ~~~ /~.:«'< 0>:)j ' 0~ ' ~~): ;>~~ ~ ~%~ «:~'\ :;:;~'\. ' '?-"" & >,y_),)%'\, ~«<~ V:~'\ I> w ~~~ ~~ ~ '?-' -~~ )>~);:; o._ ~%~ ~~ «:~'\ g, ~* ~~ ~'%. ~ )-~~ >%» ~)$);' ~«<-( ~ I> ~~ ~~ <( ~~ $-~~ ~;>$;' '««<~ ~«< %~ ~~ ~~~ ~~ ~~'\" ~0 A.);%~"- v. >,_">%"'>? {;:$(-. C. + D. + G. = F. AIR LATERAL PIPING ~~ ~,«,«< I> /,«,~ ;;>;:y~j0 ~~,; «_~~-(. I> t>... Q TANK. :, t>... ~«f:; /,;:;v,;:;v,;:;'>.... -v,;:;v,;:; -~~%~"0~0~~~~~~%~"0~~~~%%%~~~~~~~~~~~~0~~%%~~~~~~~~~ 2)-j j j: j$-}: j: >~:J/2)-}: j~/!:)-i); ~%}); ~%)'y}$)-} } %~~.:$5~,~~%50~0»>»>~'~'~''\<"~'~0S»-;0-; j } j25~->.,/'/.,//.-,%<0~'0.'<.~'0..~«(«:(~~~%~<:<00,».,/::(,/'/.,/'/,/'a/a />. /, /, /, /, //, //,//,/'/.' SECTION PIPING DEFINITIONS

22

23 SECTION BLOWER SHEAVE REPLACEMENT PART 1 GENERAL 1.1 SECTION INCLUDES: This section includes the design, manufacture, installation and start-up requirements for sheave replacement at the existing rotary positive displacement blowers at the three wastewater treatment plants (WWTPs) in the project, as shown on the Drawings and as specified. A. Scope of Work: The principal components of the blower sheave replacement shall include, but not be limited to the following: 1. Removal of obsolete components of existing blower system and delivery of salvageable parts to the Owner. 2. Sizing and identification of blower sheaves and ancillary components so that the rotational speed of the blower is reduced to provide the specified airflow at the operating discharge pressure of the aeration system installed as part of this project. 3. Ancillary components shall include, but not be limited to belts, shafts and drive guards, as required for each blower, hardware, connection devices, and all appurtenances. 4. Installation of blower sheaves and ancillary components, including minor modifications of existing plant components to facilitate installation. 5. Startup of the system. 6. Provide waste management records for any sanitary or hazardous waste. Where available, all blower system equipment shall be obtained from the manufacturer of the blower at the particular WWTP. Any equipment not available from the blower manufacturer shall be of the same manufacturer for all three WWTPs. All components shall be consistent with a 20-year service life for the installation. 1.2 RELATED SECTIONS A. Section Submittals B. Section Quality Control C. Section Materials and Equipment D. Section Contract Closeout E. Section Retrievable Fine Bubble Diffuser System F. Section Basic Electrical SKW

24 1.3 REFERENCES: Industry standard publications, including those by the following agencies or associations form a part of these specifications. The latest revisions of these publications in effect at the time of Bid opening shall be applicable. A. Anti-Friction Bearing Manufacturers Association (AFBMA). B. American Iron and Steel Institute (AISI) C. American National Standards Institute (ANSI): B16.1 B17.1 Cast Iron Pipe Flanges and Flanged Fittings Keys and Keyseats D. American Society for Testing and Materials (ASTM): A48 A240 A307 Gray Iron Castings Stainless Steel Carbon Steel Externally and Internally Threaded Standard Fasteners E. National Electric Manufacturer's Association (NEMA) 1.4 DEFINITIONS: 1. MG1 Motors and Generators A. Blower Manifold Piping: Air distribution piping between the blower discharge and Air Header Piping. 1.5 COMMON DESIGN PARAMETERS: This paragraph is applicable to all WWTPs - in addition to the requirements of Paragraph 1.6. A. Sizing and identification of blower sheaves and ancillary components shall be coordinated with the manufacturer of each blower. B. Blower operation must remain within the manufacturer specified boundary conditions for inlet airflow, blower speed, horsepower, temperature rise, belt pull, shaft moment, gear tip speed, clearances, and other manufacturer specified parameters. C. Blower rotational speed must remain within manufacturer specified boundary conditions for cooling and bearing lubrication, and other manufacturer specified parameters. D. Refer to Appendix B for information on existing blowers. 1.6 INDIVIDUAL DESIGN PARAMETERS: This paragraph is applicable to individual WWTPs - in addition to the requirements of Paragraph 1.5. SKW

25 A. All parameters are to be field-verified by the Contractor for each system. B. Only the listed blower systems are to be modified. C. For drawings of existing systems refer to the plans. D. For detailed information on existing blowers and motors refer to the manual excerpts in the appendix. Complete manuals will be provided to the Contractor upon request following award of the Contract: E. Nameplate ratings for individual WWTPs are as follows. 1. Midway Crossings WWTP: a. Number of Motors/Blowers: b. Motor Manufacturer: c: Motor Horsepower (HP): d. Motor Phase (0): e: Motor Voltage (V): (Current Operating Voltage: f. Motor Current (amps): g: Motor Speed (rpm): h: Blower Manufacturer: i: Blower Model: j. Blower Speed (rpm): 2 Baldor Electric Company/ Kaeser Compressors / ) 108/ Baldor Electric Company/ Kaeser Compressors OMEGA 53 PLUS Prairie Meadows WWTP: a. Number of Motors/Blowers: b. Motor Manufacturer: c: Motor Horsepower (HP): d. Motor Phase (0): e: Motor Voltage (V): (Current Operating Voltage: f. Motor Current (amps): g: Motor Speed (rpm): h: Blower Manufacturer: i: Blower Model: j. Blower Speed (rpm): 2 Toshiba / ) 49.2/ Gardner Denver/Sutorbilt GAELBRA 5LP South Route K WWTP: a. Number of Motors/Blowers: b. Motor Manufacturer: c: Motor Horsepower (HP): d. Motor Phase (0): 3 Marathon Electric 20 3 SKW

26 e: Motor Voltage (V): 230/460 (Current Operating Voltage: 460) f. Motor Current (amps): 48.2/24.1 g: Motor Speed (rpm): 1775 h: Blower Manufacturer: Dresser/Roots i: Blower Model: 59 URAl j. Blower Speed (rpm): SUBMITTALS: The Contractor shall submit the following in accordance with Section Submittals and Section Contract Closeout. The submittal package shall be provided in sufficient detail and scope to confirm compliance with the requirements of this section. Submittals shall be complete for all required components. Partial submittals will not be accepted. A complete separate submittal package shall be provided for each WWTP in the project A. Product Data for Review for all Blower System Replacement Components: 1. Material specifications 2. Dimensional data. B. System Design and Performance Data for Review: 1. Provide data for design flows and current flows. 2. Engineering calculations as detailed below shall be provided for the blowers to show compliance with the specifications: a. Blower system calculations shall include clearances, blower temperature, inlet airflow, blower speed, temperature rise, belt pull, shaft moment, gear tip speed, and horsepower draw on motors at current and design airflow in addition to any other manufacturer specified parameters. b. Calculations for sheave sizing, overhung load on blowers and critical velocity of blower timing gear are also required. C. Shop Drawings for Review: Detailed layout drawings for blower upgrades shall include: 1. Layout and configuration of all replacement blower components. 2. Details for replacement sheaves. 3. Details for replacement shafts, if any. D. Installation Instructions: 1. Manufacturer's Instructions for installation and guidelines for all proposed components. 2. Information on the blower system shall include, but not be limited to: a. Blower sheaves b. Blower shafts, if any. c. Ancillary components. SKW