(A) System description. Provide packaged sewer lift station system, shop assembled with basin, submersible, non-clog grinder pumps and single automatic control for in ground installation. Provide duplex system (one operating pump and one installed spare pump).
(B) General requirements. General requirements include the following:
(1) Plans and specifications for lift stations shall be prepared by a state registered professional engineer and submitted to the District for review and approval;
(2) Materials shall be corrosion resistant and rated for sewage service. Metal exposed to sewage environment must be stainless steel;
(3) Manufacturer: company specializing in manufacturing of packaged lift stations with minimum three years of experience;
(4) Environmental: comply with State Department of Public Health Water Main Separation Criteria (Title 22); and
(5) Provide and install an approved reduced pressure (RP) backflow assembly for potable water service line to lot.
(D) Product requirements.
(1) General. General product requirements include the following:
(a) Station must have a cartridge type, easily removable core assembly containing: pump, motor, grinder, motor controls, check valve, anti-siphon valve, electrical quick disconnect and wiring. Provide lifting hooks, mechanical and electrical disconnects with easy disconnect accessibility;
(b) Station must be maintainable without entry. Entry is not permitted without appropriate OSHA confined space permits;
(c) Station shall be free from electrical and fire hazards;
(d) Station shall be free from noise, odor or health hazards and shall have been tested by an independent laboratory to certify its capability to perform in sewer system applications; and
(e) Provide NSF International seal on product as evidence of compliance.
(2) Pump. Pump requirements include the following:
(a) Provide identical, submersible, non-clog grinder pumps with stainless steel impellers, shredding rings, cutters, shafts and hardware; and
(b) Pump capable of delivering negative total dynamic head without overloading the motor. Use of in-line piping or valves to create false apparent head is not permitted.
(3) Motor. Motor requirements include the following:
(a) 120/240V, 60Hz, single phase, 1800rpm max, non-overloading;
(b) Service factor: 1.15; and
(c) Provide thermal overload protection.
(4) Basin. Basin requirements include the following:
(a) Working capacity of the basin is defined as the volume between the maximum and minimum normal operating levels;
(b) Basin shall have enough working capacity to prevent pumps from starting more than four times per hour;
(c) Basin shall have capacity for emergency storage to accommodate a one-day (24-hour) lift station outage during maximum day demand;
(d) Design basin to counteract the effects of buoyancy due to high groundwater conditions. The groundwater elevation used for design shall be determined by a licensed geotechnical engineer. Ground surface may be used as groundwater level in lieu of a geotechnical report;
(e) Basin shall be suitable to prevent damage from sulfides, and use custom molded HDPE or fiberglass reinforced polyester resin;
(f) Penetrations into the basin shall resist infiltration and exfiltration;
(g) Basin shall be dual contained with a smooth internal wall to promote scouring;
(h) Basin seams shall be thermally welded, factory tested and leak-proof;
(I) Basin shall withstand saturated soil loads at maximum burial depth;
(j) Basin cover must be lockable and sufficient to withstand live load of 150 psf minimum. If basin cover is potentially accessible to vehicular traffic, provide HS20 rated cover; and
(k) Basin shall have integral bug-free vent, an inlet piping connection and a discharge piping connection.
(5) Packaged lift station piping and valves. Packaged lift station piping and valves include the following:
(a) Provide stainless steel discharge piping and hardware;
(b) Provide non-clog check valve;
(c) Provide anti-siphon valve; and
(d) Provide full port, stainless steel isolation valve.
(6) Site piping and valves. Site piping and valves include the following:
(a) Force main piping: HDPE (SDR 11) or PVC (schedule 80) with a minimum depth of cover of three feet;
(b) Provide plug-style isolation valves for buried service with corrosion resistant valve stem extension, riser and cover plate labeled “SEWER” for basin inlet and force main to permit isolation of the basin;
(c) Provide non-clog check valve immediately upstream of force main plug valve;
(d) Connect inlet and force main piping to basin with flexible connector;
(e) Valves and appurtenances shall use either of the following bolts and nuts:
1. Fluoropolymer coated carbon steel: bolts (ASTM A307, Grade B) and nuts (ASTM A563, Gr. A); and
2. 304 stainless steel: bolts (ASTM A193 Gr. B8M) and nuts (ASTM A194 Grade 8).
(f) Refer to standard plans for force main discharge.
(7) Operations. Operations include the following:
(a) Level control: non-fouling level detection with no moving parts in direct contact with wastewater;
(b) Level control points: “pump on”, “pump off” and “high level” in basin. Start pump automatically when “pump on” set-point is activated. Stop pump automatically when “pump off” set-point is activated. Signal alarm condition automatically when “high level” set-point is activated;
(c) Provide alarm dry contacts for “high level”, “low level” and “power failure”; and
(d) Sound, vibration and thermal control: dampen or suppress noise, absorb vibration, accommodate thermal expansion and stresses and adjust or correct for misalignment in piping systems.
(8) Electrical. Electrical requirements include the following:
(a) Power/alarm cable requires the following:
1. Provide NEMA 6P MELTRIC brand quick disconnect;
2. Provide cable shroud and strain relief cord connector; and
3. Provide cable for direct burial use.
(b) Back-up power: as an alternate to providing emergency storage within the basin, provide back-up power source to ensure continuous operations in the event of a power outage;
(c) Alarm/disconnect panel:
1. Corrosion resistant NEMA 4X rating; and
2. UL listed.
(d) Wiring: in accordance with requirements of National Electrical Code; and
(e) Provide local operator interface (LOI) for the District’s SCADA system. Coordinate screen development with District Engineer.
(E) Installation requirements. Installation requirements include the following:
(1) Install per manufacturer’s standard printed instructions if acceptable to the District Engineer;
(2) Seal cover penetrations with manufacturer’s recommended sealant;
(3) Set cover frames and covers level to correct elevations without tipping; and
(4) Provide basin anchorage.
(F) Startup, initial testing and operations. Startup, initial testing and operations includes the following:
(1) Notify the District three days prior to testing. Coordinate and operate pumps in conjunction with District;
(2) Provide startup and initial testing of system. District must be present to observe testing (including retests);
(3) Hydraulically test station to performance requirements by receiving, pumping and discharging 500 gallons of water to/from basin;
(4) Correct failures during test by repairing or replacing malfunctioning parts or equipment or faulty workmanship;
(5) After correcting failures, re-test. Repeat until failures are eliminated;
(6) Confirm that general sequencing of pump and level control operations at basin and control panel are in accordance with performance requirements; and
(7) Document and certify lift station system startup and initial testing results in startup report. Submit startup report to the District for review and permitting approval. Do not operate lift station without a District-approved permit.
(G) Protection of finished work. Do not allow access to general public. Provide secure, lockable access.
(H) Details required on improvement plans. Details required on improvement plans includes the following:
(1) Site plan: location of packaged sewer lift station, driveway, fencing, water services within 120 feet. Please see County Health Department specifications for additional details required on improvement plans. Provide site grading and drainage; and
(2) Basin inlet piping and force main discharge details.
(I) Record drawings. Provide three copies of approved record drawings and electronic scan of the drawings in *.TIF or *.PDF format with a minimum 200 dpi resolution, and an electronic copy in AutoCAD latest version.
(Ord. 2019-02, passed 4-25-2019)