NR 110.14(3)(j)4.4. Friction losses through force mains shall be based on the Hazen and Williams formula or other acceptable method. The roughness coefficient “C” value used for design shall be noted on the design report. NR 110.14 NoteNote: When the Hazen and Williams formula is used, the department recommends a “C” value between 100 and 125 be used for all pipe except plastic pipe. A “C” value between 120 and 140 is recommended for plastic pipe. When initially installed, force mains may have a significantly higher “C” value. The lower “C” value (higher coefficient of friction) should be considered when calculating the head at design conditions. The higher “C” value should be considered when calculating the minimum head in the pump operating range power requirements.
NR 110.14(4)(4) Suction lift pumps or wet well mounted lift stations. NR 110.14(4)(a)(a) Priming. Suction lift pumps shall be of the self-priming or vacuum primed type and shall comply with applicable requirements of sub. (3), except as modified in this subsection. NR 110.14(4)(b)(b) Lift. The total dynamic suction lift may not exceed 6.0 meters (20 feet), unless the department approves pumps which exceed this specified limit based on certified pump performance curves and detailed calculations which justify the higher heads. NR 110.14(4)(c)(c) Compartment separation. The pump equipment compartment shall be above grade, partially recessed in the ground or offset and shall be isolated from the wet well in a manner which will prevent the humid and corrosive sewer atmosphere from entering the equipment compartment. Wet well access may not be through the equipment compartment and shall be at least 61 centimeters (24 inches) in diameter or equivalent area. NR 110.14(4)(d)(d) Electrical. Float type displacement switches and electronic transducers which are used in wet wells shall comply with the applicable requirements of sub. (5). NR 110.14(5)(a)(a) Construction. Submersible pumps and motors shall be designed specifically for raw sewage use, and for total submergence during operation, and shall comply with the applicable requirements of sub. (3), except as modified in this subsection. NR 110.14(5)(b)(b) Pump removal. Submersible pumps shall be readily removable and replaceable without dewatering the wet well or disconnecting any piping in the wet well. Removal of one submersible pump from the lift station may not interrupt the operation of other pumps in the station. NR 110.14(5)(c)1.1. Electrical supply, control, and alarm circuits shall be designed to provide strain relief appurtenances. All junction boxes containing terminals and connectors shall be protected from corrosion by being located outside the wet well or through the use of a watertight seal. Junction boxes for motor power cable connections and for intrinsically safe control circuits shall meet the requirements of weatherproof equipment. NR 110.14(5)(c)2.2. The motor control center shall be located outside the wet well and be protected by conduit seals or other appropriate measures meeting the requirements of the NEC to prevent the atmosphere of the wet well from gaining access to the control center. The explosion proof seals shall be located so the pump motor and the level control float switches or transducers can be removed and electrically disconnected at the respective junction box without destroying the seal. NR 110.14(5)(c)3.3. Pump motor power cables shall be designed for flexibility and serviceability. Ground fault interruption protection shall be provided in accordance with the NEC requirements. Power cord terminal fittings shall be corrosion-resistant and constructed in a manner to prevent the entry of moisture into the cable, shall be provided with strain relief appurtenances, and shall be designed to facilitate field connecting. NR 110.14(5)(d)(d) Explosion prevention. In order to minimize the potential for ignition of explosive gases in submersible lift stations, one of the following requirements shall be met: NR 110.14(5)(d)1.1. Low water level controls may be set such that the pump motor will remain totally submerged at all times. The lift station shall be equipped with a low water alarm in addition to meeting the requirements of sub. (3) (i) 4., and which is distinguishable from the high water alarm. NR 110.14(5)(d)2.2. The pump motor may be rated for compliance with the NEC explosion proof requirements of Class 1, Group D, Division 1 locations. NR 110.14(6)(a)(a) Construction. The wet well and dry well lift stations shall be designed specifically for raw sewage use and shall comply with applicable requirements of sub. (3), except as otherwise provided in this subsection. NR 110.14(6)(b)(b) Electrical. When float type displacement switches or electronic transducers are used to control the liquid level in the wet well, they shall comply with the applicable requirements of sub. (5). NR 110.14(7)(a)(a) Applicability. Screw pumps may be approved by the department on a case-by-case basis upon submission of appropriate manufacturer’s data and the detailed design calculations. NR 110.14(7)(b)(b) Construction. Screw pumps and motors shall be designed specifically for raw sewage use, and shall comply with applicable requirements of sub. (3). NR 110.14(8)(a)(a) Applicability. Pneumatic ejectors may be approved by the department on a case-by-case basis upon submission of appropriate manufacturer’s data and the detailed design calculations. NR 110.14(8)(b)(b) Construction. Pneumatic ejectors shall be designed specifically for raw sewage use, and shall comply with the applicable requirements of sub. (3). NR 110.14(8)(c)(c) Compressors. Multiple compressors shall be provided. The compressors shall be sized to handle the maximum hour design flow with the largest compressor out of service. NR 110.14(9)(9) Grinder pump lift stations — duplex. The department may approve duplex grinder pump lift stations. All duplex grinder pump lift stations shall be designed specifically for raw sewage use. Submersible duplex grinder pump lift stations shall meet the submersible pump requirements of sub. (5), and the non-submersible type duplex grinder pump lift stations shall comply with applicable requirements of sub. (6), except that each grinder pump shall have a minimum 1¼-inch pump opening and discharge piping. The total motor horsepower requirement for each pump shall be 5 horsepower or less. NR 110.14(10)(a)(a) Applicability. The department may approve simplex or individual grinder pump lift stations if no more than 3 residential units are ultimately served by 1 pump. NR 110.14(10)(b)(b) Construction. All simplex grinder pump lift stations shall be designed specifically for raw sewage use. The submersible grinder pump shall be designed for total submergence during operation. Both the submersible and the non-submersible type simplex grinder pump stations shall comply with all of the following requirements: NR 110.14(10)(b)1.1. ‘Location.’ The location of the grinder pump stations and pressure service laterals shall be shown on the plans. NR 110.14(10)(b)2.2. ‘Flood proofing.’ Grinder pump stations located in the floodplain shall be flood proofed by constructing 2 feet above the 100 year flood elevation or by providing watertight covers. NR 110.14(10)(b)3.3. ‘Pump removal.’ Grinder pumps shall be readily removable without entry into the wet well or dewatering the wet well. NR 110.14(10)(b)4.a.a. All valving shall be accessible without entry into the wet well or dewatering the wet well. NR 110.14(10)(b)4.b.b. If a grinder pump station discharges to a common pressurized sewer, a redundant check valve shall be provided. All valves including redundant check valves shall be installed at the grinder pump station. If a grinder pump station discharges to a gravity sewer, the redundant check valve is not required. NR 110.14(10)(b)5.5. ‘Ventilation.’ All grinder pump stations shall be vented to the atmosphere either from the wet well or from the service lateral. NR 110.14(10)(b)6.6. ‘Accessibility.’ No permanent ladders or steps shall be provided in the wet wells. NR 110.14(10)(b)7.7. ‘Pump size.’ All grinder pumps shall have a minimum 1¼-inch pump inlet opening and discharge piping. NR 110.14(10)(b)8.8. ‘Velocity.’ A minimum velocity of 61 centimeters (2 feet) per second shall be maintained in the discharge piping during pump operation. NR 110.14(10)(b)9.9. ‘Separation.’ A minimum separation distance of 25 feet shall be maintained between the grinder pump lift station and a private well or any other well subject to ch. NR 812. A minimum separation of 200 feet shall be maintained between the grinder pump station and a community water system well in accordance with ch. NR 811. NR 110.14(10)(b)11.b.b. All junction boxes shall be located outside the wet well, and shall meet the requirements of weather proof equipment. Electrical supply, control and alarm circuits shall be designed to allow disconnection at the junction box, without destroying the conduit-seal. NR 110.14(10)(b)11.c.c. Level controls using float type displacement switches shall be suspended in the wet well to facilitate maintenance. NR 110.14(10)(b)12.a.a. In order to reduce the potential for ignition of explosive gases in submersible grinder pump lift stations, one of the following conditions shall be met: the low water level alarm shall be set such that the pump motor will remain totally submerged at all times; the pump motor shall be rated explosion proof in accordance with NEC requirements of Class I, Group D, Division 1 locations; or the motor shall be listed as safe and appropriate for residential use by the Underwriters Laboratories, Inc. NR 110.14(10)(b)12.b.b. In order to reduce the potential for ignition of explosive gases in non-submersible grinder pump lift stations with non-explosion proof pump motors, the pump motor shall be completely isolated from the wet well atmosphere in a separate gas tight housing. NR 110.14(11)(11) Effluent pumps. The department may approve the duplex and simplex effluent pump lift stations for septic tank effluent in accordance with the applicable requirements of subs. (9) and (10), respectively. NR 110.14(12)(a)(a) General. Provisions for emergency operation of lift stations shall be provided to prevent the discharge of raw or partially treated sewage to a surface water or to a ground surface and to prevent sewage backups into basements. NR 110.14(12)(b)(b) Lift station requirements. One of the following provisions shall be made to insure continued operation of each lift station: NR 110.14(12)(b)1.1. An on-site generator, with automatic switching and starting equipment may be installed. The generator shall have sufficient capacity to meet the total electrical demands of the pumps, controls, and auxiliary equipment. NR 110.14(12)(b)2.2. An on-site gasoline or diesel engine driven pump, with automatic switching and starting equipment may be installed. The pump shall have a capacity equal to or greater than the lift station peak design pumping rate. NR 110.14(12)(b)3.3. A portable generator may be available for use at the lift station. The generator shall have sufficient capacity to meet the total electrical demands of the pumps, controls, and auxiliary equipment. Electrical connections shall be accessible without maintenance personnel having to enter the lift station. NR 110.14(12)(b)4.4. A portable pump with a pumping capacity equal to or greater than the lift station peak design pumping rate may be available for use at the lift station. Quick disconnect fittings shall be used to connect the portable pump to the suction and the discharge line, and shall be accessible without maintenance personnel having to enter the lift station. NR 110.14(12)(b)5.5. The lift station electrical system may be connected to 2 independent electrical transmission routes which receive power from the same electrical grid network which supplies power to the lift station service area. NR 110.14(12)(b)6.6. The lift station may be equipped with a holding facility which has a capacity to hold the average design flow for a minimum period of 24 hours. NR 110.14(12)(c)1.1. Emergency operation of duplex grinder pump and effluent pump lift stations which serve more than 3 residential units shall be provided by one of the methods described in par. (b). NR 110.14(12)(c)2.2. Emergency operation provisions for duplex grinder pump and effluent pump lift stations may be waived for those stations which serve homes with private water supply systems provided it is demonstrated to the department that the lift station wet well has the capacity to hold the residual water volume of the private water system. NR 110.14 HistoryHistory: Cr. Register, November, 1974, No. 227, eff. 12-1-74; r. and recr. Register, February, 1983, No. 326, eff. 3-1-83; correction in (2) (a) 3. made under s. 13.93 (2m) (b) 7., Stats., Register, September, 1995, No. 477; correction in (2) (a) 3. was made under s. 13.93 (2m) (b) 7., Stats., Register, May, 2001, No. 545; CR 09-123: am. (1) (b) and (2) (b) 3., r. and recr. (2) (a) 3. and (3) to (5), renum. (6) and (7) to be (9) and (12) and am., cr. (6) to (8), (10) and (11) Register July 2010 No. 655, eff. 8-1-10. NR 110.15NR 110.15 General requirements for sewage treatment facilities. NR 110.15(1)(1) Design report. A design report shall be submitted with plans and specifications for all sewage treatment facilities. This report shall summarize the design hydraulic loading, design biochemical oxygen demand (BOD), suspended solids and other appropriate pollutant loading, the sizing of treatment units, pump capacities, design calculations for major treatment units, and explain any deviations from the preliminary facilities planning design information which is required by s. NR 110.09 (1) (b). NR 110.15(2)(a)(a) Design. Sewage treatment facilities shall be designed to achieve compliance with the monthly and weekly average effluent limitations for biochemical oxygen demand (BOD) and total suspended solids contained in ch. NR 210, or other WPDES permit requirements, as appropriate, or with any more stringent water quality related effluent limitations required to achieve appropriate water quality standards derived from chs. NR 102 to 106, or from any federally promulgated water quality standard for any waters of the state. NR 110.15(2)(b)(b) Treatment during construction. During construction of new facilities, treatment shall be maintained at a level not less than that which existed prior to the start of construction. NR 110.15(3)(a)1.1. All sewage treatment facilities shall be located such that they are not subject to flooding. NR 110.15(3)(a)2.2. Any sewage treatment facility located in a floodplain, or suspected to be in a floodplain, will not be approved until the flood analysis requirements of s. NR 110.09 (2) (n) are met. NR 110.15(3)(a)4.4. All sewage treatment facilities which are located in a floodplain shall be floodproofed to an elevation of at least 2 feet above the regional flood elevation. NR 110.15(3)(a)5.5. Location of a land disposal system in a floodplain will be evaluated on a case-by-case basis. NR 110.15(3)(b)1.1. No new sewage treatment facility shall be located in a floodway as defined in ss. NR 116.03 and 116.11. A change in the zoning classification of a treatment facility site from floodway to flood fringe in accordance with the procedures specified in s. NR 116.21 (6), will be acceptable only if the rezoning is complemented by the construction of a dry land access as defined in par. (c). When the facility site is rezoned from floodway to flood fringe, the dry land access requirement will not be waived. NR 110.15(3)(b)2.2. Any existing sewage treatment facility which is located in a floodway shall meet the requirements of subd. 1. if the expansion or upgrading of the facility is greater than 50% of the value of the facility. Value is defined in par. (c). NR 110.15(3)(b)3.3. Any existing sewage treatment facility which is located in a floodway will not have to comply with the requirements of subd. 1. if the expansion or upgrading of the facility is less than 50% of the value of the facility. In this instance, the dry land access requirements of par. (c) will not apply. NR 110.15(3)(c)1.1. Sewage treatment facilities shall be accessible at all times. Sewage treatment facilities located in a flood fringe shall be accessible by dry land access. Dry land access is defined as a service road which has a minimum elevation of at least one foot above the regional flood elevation. NR 110.15(3)(c)2.2. The dry land access requirement may be waived by the department if one of the following criteria is met: NR 110.15(3)(c)2.a.a. The physical characteristics of the treatment site and the surrounding area pose practical difficulties for construction of dry land access, and the isolation of the sewage treatment facility during the regional flood is less than 24 hours for mechanical treatment facilities, or 5 days for lagoon systems. The duration of the regional flood shall be calculated using the methods described in s. NR 116.07; or NR 110.15(3)(c)2.b.b. The physical characteristics of the treatment site and the surrounding area pose practical difficulties for construction of dry land access, and the treatment facility access is inundated by less than one foot of water during the regional flood. In these instances, the access roads shall be stabilized and delineated; or NR 110.15(3)(c)2.c.c. The construction costs of the expansion or upgrading of an existing treatment facility are less than 50% of the value of the existing facility. The value of the existing facility shall be calculated by subtracting the 20-year total present worth of expanding or upgrading the existing facility from the 20-year total present worth of the most cost-effective treatment alternative located at another site which is not in a floodplain. NR 110.15(3)(d)1.1. In order to minimize any potential odor, noise, and nuisances caused by sewage treatment facilities, and to enhance plant security and reliability, sewage treatment facilities shall be isolated from commercial establishments and from buildings occupied or intended for residential use, and from land which is actively being developed for commercial or residential use. The following separation distances shall be maintained: NR 110.15(3)(d)1.a.a. 150 meters (500 feet) for mechanical treatment facilities, effluent holding and polishing ponds;
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Chs. NR 100-199; Environmental Protection – General
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