DIVISION 13. - PUMPING STATIONS, OIL AND GREASE SEPARATORS, AND OTHER APPURTENANCES
Part of the Code of Ordinances of Warren, RI.
The text
Footnotes:
--- (12) --- Editor's note— Ord. of 3-9-2010 renumbered Div. 12, §§ 21-186—21-195, as Div. 13, §§ 21-186—21-195.
Sec. 21-186. - Interceptors—Grease.#
(a)
All institutions including schools or commercial establishments in which grease, fats, or oils, are waste products of food cooking or processing or in which grease, fats or oils are wasted, in connection with utensils, vat, dish or floor cleaning processes, that may be detrimental to the building sewer, the public or private sewer or sewage treatment plant and any receiving watercourse, shall install grease interceptors of an approved type. Typical applications are: restaurants - pot and pan sinks, dishwashers; and, food and meat packing and processing establishments.
(b)
Construction. Grease interceptors shall be made of durable corrosion resistant materials. They shall have a double wall trap partition, and a gas and watertight cover securely fastened in place with easy means of manual or automatic removal of grease.
(c)
Capacity. Grease interceptors shall have the grease retention capacity for the specified flow through rate as indicated in tables IV and V unless they are of the automatic draw off type, where sizing shall be according to flow rates as stated by manufacturer subject to acceptance by the town.
(d)
Installation. Where practical and feasible, one (1) grease interceptor shall be provided for each fixture or unit of equipment that discharge grease, fat and/or emulsified grease laden waste. However, where necessary, the plumbing inspector may approve grouping of two (2) or more fixtures or units on a single grease interceptor, subject to approval of the grease interceptor size and proper installation of flow control as stated herein. The grease interceptor shall in all instances be installed as close as possible to the fixture or unit served and located where it will be readily accessible for maintenance and inspection. Plans showing location shall be submitted for approval prior to construction.
(e)
Flow control. A device, which controls the rate of flow through a grease interceptor, shall be installed in accordance with the manufacturer's recommendation. On multiple discharges to a common grease interceptor, a flow control shall be installed in the waste branch leading from each fixture and shall be so rated that the combined flow from all discharges will not develop sufficient head so the established flow rate of the grease interceptor can be exceeded.
(f)
Servicing. Grease interceptors shall be of the type that can be cleaned of grease in a short period of time. Interceptors shall be easily accessible for cleaning and the accumulated materials shall be removed at such intervals as may be necessary to insure exclusion of these materials from the sewage system.
(g)
Water-cooled grease interceptors shall not be installed. Grease interceptor shall not be installed where surrounding temperatures under operating conditions are less than forty (40) degrees Fahrenheit. Grease interceptor shall not receive the discharge from a food waste grinder.
Equivalent Flow Rates Fixture-Equipment Drain Outlet or Trap Size (inches) Drainage Fixture-Unit Value Equivalent
Flow Rate
(gallons per minute)
1¼ 1 7.5
1½ 2 15.0
2 3 22.5
2½ 4 30.0
3 5 37.5
4 6 45.0
References:
1. State of Rhode Island Plumbing Code
2. National Plumbing Code
Capacity Of Grease Interceptor Total Flow-Through
Rating
(gallons per minute) Grease
Retention Capacity
(pounds)
4 8
7 14
10 20
15 30
20 40
25 50
35 70
50 100
(Ord. of 1-2002, Art. XII, § 1)
Sec. 21-187. - Interceptors/separators—Oil.#
(a)
At all commercial establishments, storage or repair garages, gasoline stations with grease and service facilities, factories, processing plants, etc., where oil laden wastes are produced, oil interceptors/separators shall be installed to intercept and separate oils from wastewater entering the building drainage system, public sewer or other point of disposal.
(b)
Construction. Oil interceptors/separators shall be made of durable corrosion resistant materials. They shall have a means of retaining solids, be fitted with a gas tight cover, have a double wall deep seal trap partition, an automatic means of diverting intercepted oils to a storage tank, and a minimum two-inch size dual vent connection in the main separating chamber.
(c)
Capacity. Oil interceptors/separators shall be sized in accordance with manufacturer's gallon per minute (gpm) rating, subject to approval by the sewer superintendent, to handle the anticipated maximum gpm flow rate of oil laden water that will be discharged from all drains served.
(d)
Installation. Oil interceptors/separators of size and type described shall be installed, subject to approval of the plumbing inspector in the building sewer and be equipped with a flow control and shall be vented to the atmosphere. Installation of a sediment interceptor shall preclude the introduction of any sanitary wastein separation.
(e)
Flow control. A device, which controls the rate of flow through an oil interceptor/separator, shall be installed ahead of the interceptor/separator in an accessible location for inspection and service. It shall be installed in accordance with the manufacturer's recommendations.
(f)
Servicing. Oil interceptors/separators shall be installed in a location readily accessible for servicing, maintenance and removal of accumulated oil and sediment at such intervals as necessary to insure exclusion of these materials from the sewage system and to insure efficient operation of the interceptor/separator.
(Ord. of 1-2002, Art. XII, § 2; Ord. of 3-9-2010)
Sec. 21-188. - Interceptors—Sediment (solids).#
(a)
All bottling establishments, slaughter houses, barber shops, car washes and other similar locations, as required by the town, where wastes bearing plaster, hair, lint, entrails, broken glass, and, strings and other solids are produced, shall install sediment interceptors as described to separate solids from wastewater entering the building drainage system, public sewer or other point of disposal.
(b)
Construction. Sediment interceptors shall be made of durable corrosion-resistant materials, and shall be equipped with a basket, screens or similar intercepting device, which is removable for cleaning.
(c)
Installation. Sediment interceptors shall be installed where required and located accessible for easy cleaning, and subject to approval of the plumbing inspector. On lavatories and sinks, the sediment interceptor shall provide a trap seal within the body to serve as the fixture trap. Installation of a sediment interceptor shall preclude the introduction of sanitary wastes into separation.
(Ord. of 1-2002, Art. XII, § 3; Ord. of 3-9-2010)
Sec. 21-189. - Roof drains.#
General purpose, parapet, gutter, cornice, deck or control flow roof drains shall not be connected directly or indirectly to the wastewater collection system.
(Ord. of 1-2002, Art. XII, § 4)
Sec. 21-190. - Floor drains.#
(a)
All areas, which are subject to water spillage, overflow of washing equipment or cleaning water shall have an approved floor drain installed. Every public rest room shall have not less than one (1) approved floor drain connected to the sanitary system. One (1) floor drain shall be installed for each four hundred (400) square feet of floor areas or major fraction thereof. All areas where food is either handled or processed shall have sanitary type of floor drains installed.
(b)
Construction.
(1)
Floor drains shall be constructed of cast iron, bronze or other durable corrosion resistant materials. All internal surfaces shall be sloped to outlet to facilitate drainage. Floor drains installed in rooms which are required to have waterproof floors shall have an integral flange, seepage openings and clamping device which will securely clamp the waterproof membrane. Each floor drain grate must be load rated to safely bear the maximum anticipated load, which will pass over it. Floor drains, which receive debris laden wastewater, shall have a suitable sediment bucket in the drain body, which will intercept and retain this debris.
(2)
In food handling/processing areas, sanitary floor drains shall have an acid resistant porcelain enamel interior (or equivalent, as approved by the plumbing inspector), and either a bronze or nickel bronze top rim and grate. Food scraps, peelings and miscellaneous kitchen debris shall be intercepted by a sediment bucket inserted in drain body. Sediment bucket shall be easily removable to permit frequent cleaning.
(c)
Installation. Floor drains shall be installed at the low points of the area to be drained, with tops of drains set flush with finished floor. Drains shall be easily accessible for maintenance.
(Ord. of 1-2002, Art. XII, § 5; Ord. of 3-9-2010)
Sec. 21-191. - Sumps and ejectors (internal plumbing only).#
(a)
Portions of building drains which cannot be discharged to the building sewer by gravity flow shall be discharged into a tightly covered and vented sump from which the contents shall be lifted (pumped) and discharged into the building gravity drainage system by automatic pumping equipment or by any equally efficient method approved by the plumbing inspector. Only such drains that must be lifted for discharge shall be discharged into sumps. All other drains shall be discharged by gravity.
(b)
Design. Sump and pumping equipment shall be so designed as to discharge all contents accumulated in the sump during operation of the emptying cycle. The storage of drainage in a sump or ejector shall not exceed a period of twelve (12) hours.
(c)
Venting.
(1)
The system of drainage piping below the sewer level shall be installed and vented in a manner similar to that of the gravity system.
(2)
Building sump vents shall be sized in accordance with the State of Rhode Island Plumbing Code.
(3)
Vents from pneumatic ejectors or similar equipment shall be carried separately to the open air as a vent terminal.
(d)
Duplex equipment. Sumps receiving the discharge from six (6) or more water closets shall be provided with duplex pumping equipment. The sump vent shall be of proper size to meet the venting requirements based on the discharge rate of the sump pump.
(e)
Sewage ejectors or sewage pumps. A sewage ejector or sewage pump receiving discharge from water closets or urinals shall have a minimum discharge capacity of twenty (20) gallons per minute. In one-family dwellings, the ejector or pump shall be capable of passing a one and one-half-inch diameter solid ball and the discharge piping of each ejector or pump shall have a backwater valve and be a minimum of two (2) inches. In other than one-family dwellings, the ejector or pump shall be capable of passing a two-inch diameter solid ball and the discharge piping of each ejector or pump shall have a backwater valve and be a minimum of three (3) inches.
(f)
Sumps for floor foundations and french drains for conveyance of ground water shall not be connected to the building drain or to the wastewater collection system. Discharge of storm waters to the sanitary sewer is forbidden.
(g)
System shall have audible alarm in a location suitable to warn the building occupants.
(Ord. of 1-2002, Art. XII, § 6; Ord. of 3-9-2010)
Sec. 21-192. - Grinder pump systems (building sewer drains).#
(a)
Individual building drains which cannot be discharged to the sewer by gravity flow due to elevation or excessive distance shall be discharged into a tightly covered and vented pump chamber, basin or station, from which the contents shall be lifted (pumped) by automatic, grinder type pumping equipment or by any equally efficient method approved by the town, and discharged into the gravity sewer system or to a low pressure sewer system which shall be discharged to a gravity sewer system.
(b)
Grinder pump stations shall be of the wet pit/dry pit type and shall consist of a grinder pump suitably mounted in a basin having minimum capacity of sixty (60) gallons and constructed of fiberglass reinforced polyester (FRP) resin or corrugated high density polyethylene (CHDPE) with a smooth inner surface. Each basin shall be furnished with an EPDM grommet or PVC closet flange to accept a minimum 4.5-inch O.D. DWV pipe. Discharge piping shall be 304 stainless steel and terminate outside the pump chamber with one and one-quarter-inch NPT fitting. All penetrations in the tank to be factory installed and sealed.
(c)
All outside installations shall be provided with a poured in place, concrete anti-floatation collar of sufficient size and weight to overcome buoyancy forces. Inlet and discharge piping shall be installed at a minimum depth of four (4) feet to assure maximum frost protection.
(d)
The grinder pump system shall be provided with a NEMA 4X electrical quick disconnect, pump removal system, shut-off valve, anti-siphon valve, and full-ported check valve assembled within the basin, with remote NEMA 3R, UL listed electrical alarm/disconnect panel with all necessary internal wiring and controls. Pumps are to have alarm light and bell with external silence push-button switch, push-to-run switch, and be capable of connection to emergency power source. Duplex units shall have alarm lights, which shall indicate which pump requires service. Pump systems must be capable of either inside or outside installation. For ease of serviceability, all pump systems shall be of like type and horsepower as manufactured by Environment One Corporation or equivalent.
(e)
The grinder pumping equipment must include an integral grinder capable of handling any reasonable quantity of "foreign objects" such as plastic, wood, paper, glass, rubber and the like which find their way into a building sewer drain as a result of carelessness or accident on the part of the building occupants. The grinder pump must be capable of processing such foreign objects without jamming, stalling, overloading or undue noise. Grinder shall process these materials to particles, which will freely pass through the pump and one and one-quarter-inch pipe system. The grinder shall be of a configuration to provide a positive flow of solids into the grinding zone with sufficient action to scour the tank free of deposits or sludge banks, which could otherwise accumulate and dislodge and impair the operation of the pump.
(f)
The grinder shall be direct driven by a single, one (1) piece stainless steel motor shaft. The grinder impeller assembly shall be securely fastened to the pump motor shaft. The grinder will be of the rotating type with a stationary hardened and ground chrome steel shredding ring spaced in accurate close annual alignment with the driven impeller assembly, which shall carry two (2) hardened type four hundred (400) series stainless steel cutter bars.
(g)
Pumps for low pressure sewer systems shall be semi-positive displacement, progressing cavity, type rated at eleven (11) gpm against a total dynamic head of ninety-two (92) feet (40 psig) and nine (9) gpm at one hundred thirty-eight (138) feet (60 psig.). The pump(s) shall be capable of operating at negative heads without overloading the motor(s). Motor shall be a minimum of 1 HP, 1725 RPM, 240 volt, 60 Hertz, 1 Phase with a minimum starting torque of 8.4 foot pounds. Pump shall have U.L. certification and be provided with motor protection sized for locked rotor and overload conditions.
(h)
All maintenance functions for the grinder pump station must be possible without entry of the grinder pump station under "OSHA 1910.146 Permit Required Confined Spaces." Therefore each pump and motor unit shall be provided with double lifting hooks with nylon lift out-harness to facilitate pump removal. Outside or underground installations shall provide access through an integral extension of the wet well assembly and shall be provided with a lockable fiberglass cover. All electrical and mechanical connections must be provided with easy accessibility and disconnecting means.
(i)
Low pressure sewer systems shall have redundant check valves and anti-siphon valves. Multiple connections to a low pressure sewer system may be permitted if designed by a qualified professional engineer and approved by the town.
(j)
No more than one (1) single family home may be connected to a single pump unit.
Recommended Grinder Pump Design Table Occupancy Type Flow Pump Units Storage
Gallons
Single-family 0—500 gpd 1 60
Duplex 500—1200 gpd 1 120
Multi-family (3-6 units) 1200—1500 gpd 2 120
Applications with greater than six (6) units shall be subject to review on a case by case basis.
(k)
Low pressure sewers shall have pressure sewer cleanouts provided if in excess of between four hundred (400) and six hundred (600) feet or at junctions of one (1) or more low pressure lines.
(Ord. of 1-2002, Art. XII, § 7; Ord. of 3-9-2010)
Sec. 21-193. - Wastewater pumping stations.#
(a)
Wastewater pumping stations shall be protected from physical damage by the one hundred-year flood and shall remain fully operational and accessible during the twenty-five-year flood. A suitable superstructure, preferably located off the right-of-way of streets and alley, shall be provided. The station shall be readily accessible during all weather conditions.
(b)
Pumping stations shall be located on a separate parcel deeded to the town. Each parcel and pump station shall conform to local zoning and building codes.
(c)
Where it may be necessary to pump wastewater prior to grit removal, the design of the wet well shall receive special attention and the discharge piping shall be designed to prevent grit settling in pump discharge lines of pumps not in operation. Vertical runs of discharge piping shall be kept to a minimum.
(d)
Wastewater pumping stations shall be submersible type. Other types as described herein may be approved where circumstances justify their use. Design considerations shall include, at a minimum, the following items:
(1)
Pump station requirements.
a.
Duplicate pumping equipment shall be provided. If only two (2) pumps are provided, either shall be capable of handling peak design flows. Where three (3) or more pumps are provided, they shall be designed to fit actual flow conditions and must be so designed that with any one (1) pump out of service the remaining pumps will have capacity to pump peak design flow.
b.
Pumps shall be capable of passing spheres of at least three (3) inches (7.6 cm) in diameter. Pump suction and discharge openings shall be at least four (4) inches (10.2 cm) in diameter.
c.
Pumps shall be designed for the specific application. Designer shall submit for review, factory certification of pump performance under the proposed operating conditions. Such information shall include static suction lift as measured from "lead pump off" elevation to center line of pump suction, friction and other hydraulic losses of the suction piping, vapor pressure of the liquid, and altitude corrections, required net positive suction head, and a safety factor of at least six (6) feet.
d.
Submersible pumps shall be provided with an effective method of removal for maintenance and replacement without dewatering the wet well or disconnection of any piping in the wet well. Pumps shall be provided with shaft seal failure alarms. All wiring shall meet National Electrical Code for class I, division 2 locations. Ground fault interruption protection shall be provided to de-energize the circuit in the event of failure of the power cable or motor housing. Cables shall be provided with strain relief appurtenances. Level sensing devices shall be removable from the surface for cleaning and maintenance.
e.
Motors shall be premium efficiency type. If variable speed motors are used, they shall be controlled by variable frequency drives and shall reliably recover from losses of system power.
f.
Provisions shall be made in the piping system for the installation of in line sewage grinders and odor control devices. Flow measurement devices shall be installed in stations. Run time meters shall be provided for each pump.
g.
Pumping station wet well shall be reinforced concrete precast or cast-in-place and designed for the structural and buoyant uplift loads. The wet well, or dry well if applicable, shall be thoroughly water proofed with high build epoxy or equal. The effective capacity of the wet well should provide a holding period not to exceed ten (10) minutes for the design average flow. Pump cycle times should be large enough to prevent motor damage. Motor starts should be limited to six (6) per hour under average design conditions. Alternating pump cycles shall not be considered as a means to reach the motor start criteria. Floor slope shall have a minimum slope of one (1) to one (1) to the hopper bottom. The horizontal area of the hopper bottom shall be no greater than necessary for proper installation and function of the inlet. Suction inlet shall be of the bellmouth type. Minimum clearance from suction inlet to bottom of wet well floor shall be d/3 where d is the suction pipe diameter in inches.
h.
Proper ventilation shall be provided for all pumping stations. There shall be no interconnection between the wet well and dry well or pump house ventilation. Adequate ventilation shall be provided for all wet wells where the pump pit is below ground, or equipment requiring maintenance and inspection are located within the wet well. For continuous operation, at least twelve (12) air changes per hour shall be provided. For intermittent operation, at least thirty (30) air changes per hour shall be provided.
i.
Access to pumps and wet well shall be sufficiently sized for the proper and safe removal of pumps and equipment or access for cleaning. All routine maintenance functions for the pump station must be possible without entry of the pump station under "OSHA 1910.146 Permit Required Confined Spaces."
j.
Level sensing devices shall be designed for pump control and high and low level alarms. Sensing devices shall be accessible for inspection and maintenance from the surface of the wet well. Fixed bubbler piping or fixed floats shall be designed to prevent clogging, fouling, or solids collection which would prevent or inhibit their proper operation.
k.
Design shall provide for emergency operations such as: power loss, phase power loss, pump failure, motor high temperature, seal leak, high and low wet well. All pumping stations shall be provided with an independent engine-generator sized so that it can handle peak flows under extended power failure conditions. Generator shall be capable of operating all pumps needed for peak flow periods, lighting, pump controls, alarm controls, heating ventilation and sump pumps. Generator shall be provided with automatic and manual start-up and automatic cut-in capability during loss of normal power or loss of any phase, and automatic exerciser, which may be set on any selected schedule to run generator through a full test cycle on a routine basis. Generator shall be provided with natural gas or diesel when utility connection is not available in street. Alarms shall be monitored by pump controller and indicate by light and horn: power failure, phase loss, pump failure, high wet well, low wet well. Alarms shall be sent from the controller to an independent programmable alarm phone dialer, which shall notify operations personnel of alarm conditions.
l.
Pump station building may be required to enclose pumps, controls, and monitoring and generator equipment. Building to provide protection from the weather and shall be heated to prevent freezing and protect equipment from vandalism. Building shall provide access to equipment for maintenance and removal of equipment. The building shall be durable masonry designed to blend into the neighborhood with consideration for appearance, noise and odor control. Screening may be required and will be subject to review by the [town]. The building shall also be subject to local building codes and zoning limitations.
m.
Safety concerns shall be addressed by the designer. When chemical oxidizing agents are used for odor control or pretreatment, appropriate safety and storage facilities shall be provided. Operator emergency eye wash stations and showers are among considerations. Local power lock-out controls shall be provided for all pumps and chemical feed systems. Adequate lighting shall be provided with proper ventilation as defined in this regulation. Lift hooks for pump removal shall be placed over the equipment in a workable location, when possible. Any special tools, lifting devices or equipment needed for service of proposed equipment shall be provided. Safety nets at hatches over pumps or over wetwells are to be provided for protection from falls or to catch failing tools.
(2)
Optional pump station requirements.
a.
Optional pump station types include dry well type, self priming suction-lift and vacuum assist. These stations may be approved where circumstances justify their use. Applicable design considerations in [this section] are to be met.
b.
Dry well stations shall provide a separate dry well and wet well with separate access and ventilation. Access to the dry well shall be by stairways for operations personnel. Access for equipment removal shall be through hatches with lift hooks to be provided. Dry wells shall be provided with dewatering sump pump(s) to remove leakage or drainage to a point of discharge above the wet well high water alarm. Floors shall be sloped at 0.02 feet per feet to the sump drain.
c.
Self-priming, suction-lift stations are not desirable due to energy requirements during priming.
d.
Self-priming, flooded suction pumps may be used in a dry well type station.
e.
Additional requirements may be made on the design of pumping stations, as required by the town. Additional requirements may also be made as stated in these regulations.
(Ord. of 1-2002, Art. XII, § 8; Ord. of 3-9-2010)
Sec. 21-194. - Equipment inside buildings.#
All interceptors (grease, oil and solids) and appurtenant works and equipment installed inside buildings shall be in compliance with the Rhode Island Plumbing Code and the installation shall be inspected by a plumbing inspector.
(Ord. of 1-2002, Art. XII, § 9)
Sec. 21-195. - Low pressure sewer systems.#
(a)
Low pressure sewer systems serving more than one (1) low pressure sewer service shall meet all conditions of these regulations.
(b)
Low pressure sewer systems shall be designed for a flushing velocity of two (2) feet per second based on the design flow, discharge head, friction loss, accumulative head loss, pipe size, number of grinder pumps connected to each branch.
(c)
Design to be certified by a registered professional engineer.
(Ord. of 1-2002, Art. XII, § 10)