SECTION WASTEWATER TREATMENT SYSTEM

Transcription

1 SECTION WASTEWATER TREATMENT SYSTEM PART 1 GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this Section. 1.2 SUMMARY A. The contractor shall furnish all labor, materials, tools, equipment to perform all work and services necessary for and incidental to the furnishing and installation of a complete Wastewater Treatment System, complete and ready for operation in accordance with the provisions of the contract documents. B. This Section includes the following: 1.3 SUBMITTALS a. Materials of Construction b. Primary Clarifier/Sludge Holding c. Flow Equalization d. Two Stage Moving Bed Biological Reactor (MBBR) e. Secondary Clarifier f. Ultraviolet Disinfection g. Master Control Panel System A. The following, at a minimum, shall be submitted for the various equipment items and systems included in these specifications: a. Prior to fabrication, manufacturer shall prepare shop drawings for the complete Prefabricated WWTP including structural and opening details, equipment mounting and location details, and manufacturer s cut sheets for each item of equipment in the system. The main component of the submittals shall be an 11 x17 drawing of the complete prefabricated system prepared by the manufacturer. Manufacturer s cut sheets shall provide 3-D modeling of the complete system and indicate capacities, dimensions, and materials of construction for all equipment in the prefabricated SRTP system. b. Drawings shall show assembly, accessories, installation details/specifications and electrical requirements. c. Biological process design calculations for the wastewater treatment system. Wastewater Treatment System

2 d. Manufacturer s product data for all aeration blowers, including blower curves and calculations showing how discharge conditions were determined for each blower. e. Control panel schematics, control panel and field wiring diagrams and manufacturer s catalog information for each panel component. f. The manufacturer shall prepare a complete operations and maintenance (O&M) manual for the complete Prefabricated SRTP WWTP. The O&M manual shall include routine maintenance requirements and spare parts lists for each major item of equipment in the lift station. The names and telephone numbers of companies where spare parts and/or trained service technicians are available shall also be included for each item of equipment. B. The Engineer shall review and return a copy of the submittals. The returned copy shall be marked Approved, Approved as Noted, or Revise and resubmit. 1.4 QUALITY ASSURANCE A. The Drawings and Specifications are based on a factory assembled Prefabricated Wastewater Treatment System as designed, assembled, manufactured, and integrated by AppTech Solutions, LLC, 3993 Daugherty Rd., Salem, Virginia 24153, (540) B. The manufacturer shall be regularly engaged in the design, manufacture, assembly, and production of equipment of the type specified and shall have complete responsibility for the final design and furnishing of all components in the system. C. The manufacturer shall be in the business of designing and manufacturing Structurally Reinforced Thermoplastic (SRTP) vessels of eight (8) foot diameter of greater. Manufacturer shall demonstrate experience with electrofusion and thermoplastic welding with materials conforming to the requirements of ASTM F- 1055, F and F894 13, as those sections that pertain to the fabrication of SRTP vessels. 1.5 DELIVERY, STORAGE, AND HANDLING A. Deliver, store, and handle all equipment to prevent bending and damage in accordance with the manufacturer s published unit handling and installation specifications. Transport trailer beds shall be fitted with dunnage support during shipment. Fabric straps shall be used for tie down B. All fittings and openings shall be covered to exclude road splash, precipitation, and other avoidable internal contamination. C. All Equipment shall be stored on clean, level and dry ground to prevent undue damage. Wastewater Treatment System

3 D. Store all electrical equipment off the ground in a dry location until it is mounted and supplied with electrical service. The contractor shall also insure that all pump power and control cables, as well as float cables are protected from submergence until they are properly installed and sealed. 1.6 TREATMENT SYSTEM PERFORMANCE REQUIREMENTS A. The treatment system shall be designed to treat the following maximum influent flow rates: Average Daily Flow = Peak Hourly Flow Rate = GPD GPD B. The treatment system components shall collectively be designed to treat the maximum influent concentrations to the required effluent concentrations as noted on the Construction Documents: C. The wastewater treatment system is designed on the assumption that the wastewater does not contain any threshold concentration of inorganic pollutants or other such materials, solutions, or products that are inhibitory to biological treatment processes. Wastewater Treatment System

4 PART 2 PRODUCTS 2.1 MATERIALS OF CONSTRUCTION A. The SRTP Vessel and shall be profile wall cylindrical HDPE material with steel reinforcing or profile wall structural cross sections. Steel Reinforced SRTP shall meet ASTM F Standard Specification for Steel Reinforced Polyethylene (PE) Corrugated Pipe. Profile Wall SRTP shall meet F Standard Specification for Polyethylene (PE) Large Diameter Profile Wall Sewer and Drain Pipe. B. All HDPE Materials supplied under this specification shall be high density, high molecular weight PE 3408 polyethylene compound that meets or exceeds ASTM D3350. C. High density polyethylene (HDPE) pipe and fittings, joined together with heat fusion, shall be used for all penetrations. All HDPE pipe shall adhere to Section 2.3.B and as listed by the Plastic Pipe Institute in PPI TR-4 with HDB ratings of 1600 psi (11.04 MPa) at 73 F (23 C) and 800 psi (5.52 MPa) at 140 F (60 C) D. All external bulkheads shall be fabricated of structurally reinforced high density polyethylene (HDPE) materials designed to support a fully saturated soil hydraulic load. Bulkhead shall be reinforced with HDPE or steel stiffeners where required. Bulkheads shall be designed to a 2% maximum deflection while subjected to a maximum loaded condition. E. All internal walls, baffles and hopper bottoms shall be fabricated of high density polyethylene (HDPE) materials designed to support a short term hydraulic loading condition due to periodic chamber pump outs. Baffles shall be designed to a 2% maximum deflection while subjected to a maximum loaded condition. F. Vessels shall have access hatches as shown on the drawings. Access risers and hatches shall be watertight to prevent infiltration of ground water into the wastewater treatment system. G. All inlets and outlets shall be HDPE flat flanged type. Flanges shall be standard 150# rated with standard bolt patterns. H. All aeration piping within the wastewater treatment plant shall be Schedule 80 PVC pipe and fittings except as may be noted otherwise in other sections of the specifications or called for on the plans. I. All fluid piping within the wastewater treatment plant shall be Schedule 40 PVC or HDPE pipe and fittings except as may be noted otherwise in other sections of the specifications or called for on the plans. J. Stainless Steel fittings and pieces may be utilized as specified or otherwise noted in the construction drawings. The use of cast iron, ductile iron, steel, or copper fittings, pipe, or equipment is strictly prohibited. Wastewater Treatment System

5 K. The system shall be factory assembled, so far as possible, with all piping and controls. 2.2 PRIMARY CLARIFIER/SLUDGE HOLDING A. A primary clarification/sludge holding chamber shall be provided that shall be sized with a minimum volume of gallons to handle % of the daily design flow. B. The primary clarifier will provide pretreatment of the wastewater prior to conveyance to the Flow Equalization chamber. In this manner, solids settling will permit pretreatment that will remove up to 65% of incoming Suspended Solids and up to 35% of the incoming BOD due to gravity clarification and anaerobic digestion of settled solids that will collect in the tank. The primary clarifier also serves as a waste sludge holding tank in that the wastewater operator can pump excess waste biomass from the Secondary Clarifier or other such unit process to the sludge holding tank. When this is performed, waste biomass will settle from suspension and combine with settled solids already contained within the primary clarifier. The combined Primary Clarifier/Sludge Holding chamber will further promote enhanced nutrient removal based on the readily understood concept that when an activated sludge/nitrified biomass is pumped to an anaerobic or anoxic chamber, the biomass can alter its facultative metabolism to process available nitrites and nitrates for each compound s oxygen components thereby freeing the nitrogen gas to effervesce into the atmosphere. C. Chamber shall include an internal stilling baffle as specified in the construction documents. D. Flow into the chamber shall be via a standard tee with downpipe as shown on the drawings. E. Flow from the chamber shall be via a gravity effluent filter assembly configured to facilitate the design influent flow rate. Each effluent filter shall be installed level, and shall be positioned under the access hatch as required to permit the filter cartridge(s) to be withdrawn vertically through the hatch. F. Provide an integral high water alarm float with the effluent filter assembly if so equipped. G. Provide an emergency gravity overflow to the flow equalization chamber. H. Provide access and maintenance ports along the Primary Clarifier for sludge pumping at a maximum spacing of ten feet. 2.3 FLOW EQUALIZATION A. A Flow Equalization chamber shall be provided and shall be sized with a minimum volume of gallons. The flow equalization tank shall allow for a constant flow through the plant by equalizing flow surges that may occur during peak flow periods. Wastewater Treatment System

6 B. The Flow Equalization chamber shall be aerated utilizing stainless steel coarse air diffusers to prevent wastewater septicity and to reduce odors. Provide a minimum of CFM of air per 1000 cubic feet of influent wastewater. C. Discharge from the equalization chamber shall be via a duplex alternating submersible electric sewage pumping system. Pumps shall be sized to match the flow ADF flow rate of the treatment unit and shall be equipped with base elbows and slide rails to permit easy removal and replacement. The pumps shall be timedosed using a low, medium, and high volume dosing method to provide influent to downstream processes D. Mercury float switches are provided as shown on the drawings. Low, middle, and high floats operate the pumps at predetermined, adjustable dosing times. E. A duplex set of flow equalization pumps shall be provided within the flow equalization chamber. The pumps shall be of the submersible sewage type; each pump shall be furnished with a slide rail system for ease of removal from the flow equalization chamber. The slide rail system shall be complete with rail base and upper guide assembly. A stainless steel lifting cable shall be provided for each pump to aid in pump removal. F. The pump motors shall be of the submersible type, oil filled, hermetically sealed and shall be thermally protected. The overload element shall automatically reset when motor cools. Motor windings shall be of the Class B insulation rating. The rotor shaft shall be made of 416 stainless steel and shall be supported by lower and upper ball bearings. G. A simplex blower/motor unit mounted in a weather-proof housing, if specified, or a linear air pump shall be supplied to meet the air requirements of the mixing diffuser(s). Blowers shall be the manufacturer s standard package as specified on the drawings or equal. Each blower motor unit shall be complete with an inlet filter silencer, check valve, gate valve, pressure relief valve and pressure gauge. 2.4 ANOXIC BIOREACTOR (ABR) A. An Anoxic Bioreactor (ABR) shall be included to provide denitrification and shall be sized with a minimum volume of gallons. B. The minimum required retention time for design shall not be less than hours. C. Provide a mixing system consisting of an airlift pumping device or electric mixer as specified on the drawings. The mixing device will be a positive displacement airlift pump type, located in a position to keep the media in suspension. The airline supplying air to the mixing device will be equipped with a valve to regulate the rate of mixing. D. A ph probe shall be provided as noted in section 2.8, this division. Wastewater Treatment System

7 2.5 MOVING BED BIOLOGICAL REACTOR (MBBR) A. A Moving Bed Biological Reactor (MBBR) shall be provided to achieve nitrification that shall be sized with a minimum volume of gallons. B. The minimum required aeration retention time for aeration chamber shall not be less than hours. C. Provide a properly sized stainless steel or PVC coarse bubble aeration diffuser system to mix the incoming wastewater and fixed film media and to transfer atmospheric oxygen to the biomass. To ensure maximum retention, enhance spiral rotation and eliminate short-circuiting of raw sewage, the aeration diffusers shall be placed longitudinally along the center of the entire chamber. Each air diffuser will be constructed with an integral air check diaphragm designed to handle a wide range of airflow. The oxygen transfer capacity of each diffuser will be such that an adequate supply of oxygen will be maintained in the chamber to meet treatment requirements of the design sewage load. D. Provide a mixing system consisting of an airlift pumping device or electric mixer as specified on the drawings. The mixing device will be a positive displacement airlift pump type, located in a position to keep the media in suspension. The airline supplying air to the mixing device will be equipped with a valve to regulate the rate of mixing. E. Provide neutrally buoyant dynamic HDPE media to provide a protected surface for the growth of a diverse biofilm community. The media shall have a minimum surface area of 152 ft 2 /ft 3 and a minimum protected surface area of 113 ft 2 /ft 3 that shall allow for a high concentration of microorganisms to thrive within the internally protected areas and significant void space to eliminate biomass plugging and allow for transfer of oxygen and nutrients to the biofilm. The approximate dimensions of the media shall be 0.80 inches in diameter and inches long. The media shall be resistant to a wide range of aqueous solutions, acids, alkalis, oxidizing agents, oils, fats and alcohols. F. Provide appropriately sized plastic media retention screens at both ends of the chamber to retain the HDPE media in the MBBR chamber. The screens shall provide adequate flow through capacity and shall be manufactured from HDPE, PP, or PVC. Provide hydraulic performance data substantiating the media screen hydraulic conveyance capacity. G. Provide blower/motor unit(s) mounted in a weather-proof housing, if specified, to provide air to the coarse air diffusers and the RAS/WAS Pump(s) in the Secondary Clarifier as shown on the drawings. The blower(s) shall be the manufacturer s standard ALITA Linear Air Blowers as specified on the drawings or equal. Each blower motor unit shall be complete with an inlet filter silencer, check valve, gate valve, pressure relief valve and pressure gauge. H. An ORP and Temperature probe shall be provided as noted in section 2.8, this division. Wastewater Treatment System

8 2.6 SECONDARY CLARIFIER A. Provide Secondary Clarifier chamber(s) with hopper bottom to collect concentrated biomass or waste sludge as shown on the Drawings. The minimum required retention time for design shall not be less than hours. B. The bottom of the chamber(s) will be formed into an inverted pyramidal hopper, as shown on the drawings. The slope of the hopper walls will not be less than 1.7 vertical to 1.0 horizontal. C. Gravity Flow into the chamber shall be via a standard tee(s) with downpipe and energy dissipater(s) as shown on the drawings. D. Gravity Flow from the chamber shall be via a gravity effluent filter assembly, as shown on the drawings, designed and configured to facilitate the design influent flow rate. E. Each effluent filter, if specified, shall be installed level, and shall be positioned under the access hatch as required to permit the filter cartridge(s) to be withdrawn vertically through the hatch. F. Sludge shall be removed from the clarifier(s) using a positive displacement air lift pump, Geyser Pump or equal, with unions as specified on the drawings. When specified, the Pump shall be utilized as both a Return Activated Sludge (RAS) pump to return sludge to the upstream bioreactor and/or a Waste Activated Sludge (WAS) pump to periodically pump sludge to the Sludge Holding Chamber. The pump shall have a recirculation capacity ranging from 0% to 150% of the design flow. The airline supplying air to the pump will be equipped with a ball valve to vary the amount of air supplied to each pump, thus varying the capacity of the pump. G. Provide a positive scum and skimming recirculation system consisting of an airlift skimming device as specified on the drawings. The skimming device will be a positive displacement airlift pump type, located in a position to skim and return floating material to the MBBR chamber. The airline supplying air to the skimming device will be equipped with a valve to regulate the rate of return. The scum intake will have a telescoping adjustment assembly that will enable exact positioning of the skimmer at or immediately below water level. 2.7 SUPPLEMENTAL CHEMICAL FEED SYSTEM (if required) A. A chemical metering pump shall be included with the wastewater treatment system to provide supplemental as needed. The metering pump shall sit atop the chemical storage tank. The metering pumps shall be model as manufactured by LMI or approved equal. B. Provide a gallon chemical storage tank for. 2.8 INSTRUMENTATION Wastewater Treatment System

9 A. A water-tight (meeting the NEMA 6P, IP68 Protection Rating requirements) resistance temperature detector (RTD) with measurement range of -60 to 320ºF shall be provided. Temperature sensor shall include a transmitter equipped with a 2-wire, 4-20 ma output. B. A ph probe, capable of submersion, with an operating range between 0-14 ph shall be provided and installed. The probe shall operate within 14 F to 185 F. C. An oxidation-reduction potential (ORP) probe, capable of submersion, with a ±2000 mv output shall be provided. The probe shall operate within 14 F to 185 F. D. ph and ORP probes shall be provided with submersible preamps that provide watertight connections between the preamp and electrode. Transmitter shall be equipped with a 2 wire, 4-20 ma output. 2.9 MISCELANOUS EQUIPMENT A. A properly sized effluent filter with 1/16 inch or 1/32 inch filtration slots shall be provided by manufacturer. The filter shall have an automatic shutoff valve for cleaning the filter. B. Float switch assemblies shall be narrow angle, control duty mercury float switches unless otherwise noted. Switches shall be normally open and contacts become closed when the switch lifts from the hanging position. C. Duplex UV disinfection units shall be provided. Each unit shall be capable of 3 GPM flow wastewater effluents with BOD and TSS less than 30 mg/l. Lamp shall provide 99.9% Fecal coliform reduction at end-of-life (2 years). Lamp output shall rated for continuous operation and 90% output shall be at nanometers with dose greater than 55,000 microwatt-seconds/cm MASTER CONTROL PANEL SYSTEM A. Provide Master Control Panel System installed within a NEMA rated weatherproof enclosure that receives inputs from all sensors and controls outputs to all blowers and linear air pumps that control influent pumping, influent aeration, anoxic mixing, bioreactor aeration and mixing, return activated sludge (RAS) pumping and waste activated sludge (WAS) pumping as specified. The electrical controls shall consist of magnetic starters, program timers and switches necessary to automatically control all electrical devices and/or motors on the wastewater treatment system. An integral Programmable Logic Controller (PLC) shall be provided as indicated in the construction documents and housed within the control panel enclosure. B. The PLC shall receive signaling from the field sensors and devices to provide automatic operation of the treatment plant. The PLC shall provide operator programming capability such that various set points can be adjusted to suit treatment system requirements. PLC shall include a Human Machine Interface (HMI) device (touchscreen display panel) to facilitate system operations and improve operator functionality. The PLC shall include manufacturer specific Wastewater Treatment System

10 computer programs developed to operate the treatment system. The PLC shall include Ethernet capability with local Cat-5 terminal connection at the panel or a wireless network card. C. Provide soft H-O-A selector switches and magnetic starters in conjunction with the program timer will control the blower/motor. The program timers will have the capability to operate the treatment system when required as determined by the variation in the daily flow rate. Properly sized circuit breakers and fuses will protect all electrical equipment and circuitry. The control system will be designed to operate all duplex or standby equipment. D. The enclosure will be wired for volt, phase, wire, incoming power. E. The panel shall be equipped with a safety handle breaker main disconnect switch that will deactivate incoming power when the panel is opened. F. Provide a red flashing strobe light and alarm horn. Light and horn attached to the exterior of the panel. Horn shall have an external silence button and an alarm test button. G. Control Panel shall be manufactured in conformance with the Functional Description, Process of Operation, and Process and Instrumentation Diagram provided in the Construction Documents. Wastewater Treatment System

11 PART 3 EXECUTION 3.1 INSTALLATION A. Installation of the treatment system shall be in strict conformance with the manufacturer s installation guide and manual as supplied with the treatment unit. Deviation from the installation guide shall not be permitted unless authorized by the manufacturer in writing. B. The wastewater treatment plant shall be constructed to the lines and grades as shown on the Drawings. C. Install the wastewater treatment vessels in accordance with the manufacturer s specifications. D. Piping shall be bedded in accordance with the requirements of Division 2. E. Connect all electrical components to the package wastewater treatment plant in accordance with the requirements of Division 16. F. Contractor shall be responsible for preventing any and all units from flotation. Flotation resistance shall be provided in accordance with the manufacturer s specifications. G. Manufacturer shall provide the remote services of a field representative to advise on the wastewater treatment plant field installation. The services of the field representative shall include at least four hours of available time including participation in a preconstruction conference call with the Contractor. The Contractor shall notify the manufacturer a minimum of ten (10) working days prior to the time that the field services are desired. 3.2 START-UP AND TRAINING SERVICES A. The Contractor shall notify manufacturer when the installation of the wastewater treatment plant equipment has been completed. A representative of the supplier shall inspect the installation. Manufacturer shall advise the Contractor, Owner, and Engineer in writing of any corrections or adjustments that are required for the wastewater treatment plant equipment installation. After the wastewater treatment plant installation has been completed to the supplier's satisfaction, manufacturer shall furnish to the Contractor, Owner, and Engineer a letter of certification that all equipment is installed in accordance with its instructions and that the wastewater treatment plant is ready for operation. B. Upon receipt of a letter from the Contractor certifying that the wastewater treatment plant installation is ready for start-up, manufacturer shall provide the services of a field person for a total of one eight (8) hour day. Time of trip shall be coordinated with Owner. The field person shall do a functional check of each item furnished by the manufacturer, and start-up of the process. During this time, the field representative will provide not less than four (4) hours of operation training for Owner's personnel, which shall include familiarization with the wastewater Wastewater Treatment System

12 treatment plant process, its requirements, and review of the Operation and Maintenance manuals. 3.3 START-UP AND TRAINING SERVICES A. Contractor shall perform a clean water test on the installed system prior to final inspection in the presence of the Owner and the Engineer. It will be the Contractor s responsibility to provide the water. 3.4 WARRANTY A. The Contractor shall provide a one (1) year warranty to warranty the equipment and labor for the wastewater treatment plant. 3.5 OPERATION AND MAINTENANCE MANUAL A. Contractor shall provide Owner with three (3) copies of an Operation and Maintenance Manual for proper operation and maintenance of the wastewater treatment plant. The manual shall include description of treatment process and equipment operation; shop drawings, field reports, operation and maintenance procedures, process control guidelines, equipment specifications, schedules, and spare parts information. A recommended list of spare parts shall be provided. END OF SECTION Wastewater Treatment System