NR 811.862(2)(2) The settled filtered backwash wastewater shall be returned to the head end of the plant at a maximum rate of 10% of the instantaneous flow rate at which raw water is entering the plant. All of the following requirements shall be met: NR 811.862(2)(a)(a) The point of recycle shall be prior to all treatment and chemical addition except chemical treatment for zebra mussel control at the intake. NR 811.862(2)(c)(c) A means shall be provided for controlling the rate at which the settled backwash wastewater is returned. NR 811.862(3)(3) For systems treating groundwater, the settled filtered backwash wastewater shall be disinfected prior to or at the time that it is returned to the head end of the plant. NR 811.862(4)(4) Reservoirs to be used to settle backwash wastewater for plants treating potable groundwater shall be constructed to potable reservoir construction standards as required by subch. IX. The discharge of any wastewater or sludge, or both, from such a reservoir to a sanitary or storm sewer main, manhole, or other collection structure, whether by pump or by gravity, shall not be made through a direct connection. The discharge piping shall terminate downward with a one-foot free air break over the receiving structure as required in s. NR 811.64 (4). NR 811.862(5)(5) For surface water systems that recycle their backwash wastewater, all of the following reporting and record keeping requirements apply: NR 811.862(5)(a)(a) A current plant schematic showing the origin of all recycle streams, how any recycle streams are transported, and where the recycle streams enter the treatment process shall be maintained on file with the department. NR 811.862(5)(b)(b) Information on the typical recycle flow rate, the highest observed plant flow rate each year, and the design flow rate of the plant shall be available to the department upon request. NR 811.862(5)(c)(c) The information in pars. (a) and (b) along with all of the following information shall be maintained on file for a minimum of 10 years: dates when recycle flow rate has exceeded 10 percent of raw water flow rate entering the plant; how recycle flow rate is controlled; dimension and volume of backwash equalization basin; typical detention time in equalization basin; type of coagulant fed prior to equalization basin; and means of sludge removal from the equalization basin. NR 811.862 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (1) (b) Register January 2024 No. 187, eff. 2-1-24. NR 811.87(1)(1) Approval of the department is required prior to the construction of any aquifer storage recovery well or the conversion of any previously constructed well for use as an aquifer storage recovery well. NR 811.87 NoteNote: Approval to construct or develop an aquifer storage recovery well is not an approval to operate an ASR system.
NR 811.87(2)(2) Approval of the department is required prior to the operation of any aquifer storage recovery system. NR 811.87 NoteNote: The department will not issue an approval to operate an ASR system until after it has reviewed and evaluated the results of an approved ASR pilot study.
NR 811.87(3)(3) Only treated drinking water may be placed underground through an ASR system well. NR 811.87(4)(4) Only a municipal water system may construct an aquifer storage recovery well or operate an ASR system. NR 811.87(5)(5) The displacement zone around an ASR well may extend no further than 1,200 feet from that ASR well. NR 811.87 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10. NR 811.88NR 811.88 ASR well performance requirements. NR 811.88(1)(1) Unless the department determines that it is not technically or economically feasible, the quality of the treated drinking water to be placed underground through an aquifer storage recovery well shall comply with the preventive action limits contained in ch. NR 140 prior to underground injection. In all cases, the quality of the treated drinking water to be placed underground through an aquifer storage recovery well shall meet the primary drinking water standards contained in ch. NR 809 and may not contain any substance at a concentration that exceeds a state or federal health advisory prior to underground injection. NR 811.88 NoteNote: Pursuant to s. 160.19 (2) (b), Stats., the department finds that treated drinking water in a municipal water system may at times exceed preventive action limits established for iron, manganese, nitrate, nitrite, copper, lead, fluoride, asbestos, chloroform, bromoform, bromodichloromethane, and dibromochloromethane. Such exceedances may occur at the point of underground injection and within the displacement zone surrounding an aquifer storage recovery well even though the treated water being injected would remain in compliance with federal and state water quality standards for drinking water. The maximum allowable concentration of a primary drinking water contaminant in treated drinking water has been set by the United States Environmental Protection Agency at the lowest level that is considered to be technically and economically achievable at this time. The department also finds that it is not technically or economically feasible to require that residual concentrations of chloroform, bromoform, bromodichloromethane, and dibromochloromethane be removed from the injected water when a disinfection residual is desired at the wellhead to provide additional protection to the water system from potential biological contamination. NR 811.88(2)(2) All water that is retrieved through an aquifer storage recovery well shall comply with the primary drinking water standards contained in ch. NR 809 and shall be treated to provide a disinfectant residual prior to recovery into any municipal water distribution system. NR 811.88(3)(3) The quality of treated drinking water stored in a displacement zone shall at all times comply with the primary drinking water standards contained in ch. NR 809. ASR systems shall be designed and operated to maintain compliance with the groundwater standards contained in ch. NR 140, as required by s. NR 140.22. Therefore, treated drinking water stored underground in an ASR system shall comply with the applicable enforcement standards established in ch. NR 140 prior to movement beyond the property boundary of the ASR well site. NR 811.88 NoteNote: An ASR well site is considered to include lands adjacent to the ASR wellhead that are directly owned by the municipal water system and any contiguous properties that are directly owned by the local unit of government of which the water system is a subunit.
NR 811.88(4)(4) At the completion of each aquifer storage recovery cycle, the subsurface water in any portion of a displacement zone may not attain or exceed ch. NR 140 enforcement standards for iron, manganese, nitrate, nitrite, copper, lead, fluoride, asbestos, chloroform, bromoform, bromodichloromethane or dibromochloromethane or ch. NR 140 preventive action limits established for any other substance. The department may grant an exemption from this requirement, in accordance with s. NR 140.28, when an ASR well or ASR system is located in an area where the background concentration of a substance attains or exceeds the groundwater preventive action limit or enforcement standard established for that substance. NR 811.88 NoteNote: Pursuant to s. 160.19 (2) (b), Stats., the department finds that routine operation of an ASR system may result in an exceedance of the preventive action limits established for iron, manganese, nitrate, nitrite, copper, lead, fluoride, asbestos chloroform, bromoform, bromodichloromethane, and dibromochloromethane in a displacement zone. An ASR cycle is normally completed when the volume of water recovered equals the volume of water that was originally injected; however, the department recognizes that some of the treated drinking water injected during an aquifer storage recovery cycle may remain in an aquifer at the completion of the cycle and that substances present in this residual treated drinking water may result in ch. NR 140 preventive action limits being exceeded in an aquifer at the completion of an aquifer storage recovery cycle.