Chapter NR 664

NR 664.0221(1) (1) Any surface impoundment that is not covered by sub. (3) or s. NR 665.0221 shall have a liner for all portions of the impoundment (except for existing portions of the impoundment). The liner shall be designed, constructed and installed to prevent any migration of wastes out of the impoundment to the adjacent subsurface soil or groundwater or surface water at any time during the active life (including the closure period) of the impoundment. The liner may be constructed of materials that may allow wastes to migrate into the liner (but not into the adjacent subsurface soil or groundwater or surface water) during the active life of the facility, provided that the impoundment is closed in accordance with s. NR 664.0228 (1) (a). For impoundments that will be closed in accordance with s. NR 664.0228 (1) (b), the liner shall be constructed of materials that can prevent wastes from migrating into the liner during the active life of the facility. The liner shall be all of the following:

NR 664.0221(1)(a) (a) Constructed of materials that have appropriate chemical properties and sufficient strength and thickness to prevent failure due to pressure gradients (including static head and external hydrogeologic forces), physical contact with the waste or leachate to which they are exposed, climatic conditions, the stress of installation and the stress of daily operation.

NR 664.0221(1)(b) (b) Placed upon a foundation or base capable of providing support to the liner and resistance to pressure gradients above and below the liner to prevent failure of the liner due to settlement, compression or uplift.

NR 664.0221(1)(c) (c) Installed to cover all surrounding earth likely to be in contact with the waste or leachate.

NR 664.0221(2) (2) The owner or operator will be exempted from the requirements of sub. (1) if the department finds, based on a demonstration by the owner or operator, that alternate design and operating practices, together with location characteristics, will prevent the migration of any hazardous constituents (see s. NR 664.0093) into the groundwater or surface water at any future time. In deciding whether to grant an exemption, the department will consider all of the following:

NR 664.0221(2)(a) (a) The nature and quantity of the wastes.

NR 664.0221(2)(b) (b) The proposed alternate design and operation.

NR 664.0221(2)(c) (c) The hydrogeologic setting of the facility, including the attenuative capacity and thickness of the liners and soils present between the impoundment and groundwater or surface water.

NR 664.0221(2)(d) (d) All other factors which would influence the quality and mobility of the leachate produced and the potential for it to migrate to groundwater or surface water.

NR 664.0221(3) (3) The owner or operator of each new surface impoundment unit on which construction commences after June 1, 1995, each lateral expansion of a surface impoundment unit on which construction commences after June 1, 1995 and each replacement of an existing surface impoundment unit that is to commence reuse after June 1, 1995 shall install 2 or more liners and a leachate collection and removal system between the liners. “Construction commences” is as defined in s. NR 660.10 under “existing facility”.

NR 664.0221(3)(a) (a)

NR 664.0221(3)(a)1. 1. The liner system shall include both of the following:

NR 664.0221(3)(a)1.a. a. A top liner designed and constructed of materials (e.g., a geomembrane) to prevent the migration of hazardous constituents into the liner during the active life and long-term care period.

NR 664.0221(3)(a)1.b. b. A composite bottom liner, consisting of at least 2 components. The upper component shall be designed and constructed of materials (e.g., a geomembrane) to prevent the migration of hazardous constituents into this component during the active life and long-term care period. The lower component shall be designed and constructed of materials to minimize the migration of hazardous constituents if a breach in the upper component were to occur. The lower component shall be constructed of at least 3 feet (91 cm) of compacted soil material with a hydraulic conductivity of no more than 1x10-7 cm/sec.

NR 664.0221(3)(a)2. 2. The liners shall comply with sub. (1) (a), (b) and (c).

NR 664.0221(3)(b) (b) The leachate collection and removal system between the liners, and immediately above the bottom composite liner in the case of multiple leachate collection and removal systems, is also a leak detection system. This leak detection system shall be capable of detecting, collecting and removing leaks of hazardous constituents at the earliest practicable time through all areas of the top liner likely to be exposed to waste or leachate during the active life and long-term care period. The requirements for a leak detection system in this subsection are satisfied by installation of a system that is, at a minimum, all of the following:

NR 664.0221(3)(b)1. 1. Constructed with a bottom slope of 1% or more.

NR 664.0221(3)(b)2. 2. Constructed of granular drainage materials with a hydraulic conductivity of 1x10-1 cm/sec or more and a thickness of 12 inches (30.5 cm) or more; or constructed of synthetic or geonet drainage materials with a transmissivity of 3x10-4 m2/sec or more.

NR 664.0221(3)(b)3. 3. Constructed of materials that are chemically resistant to the waste managed in the surface impoundment and the leachate expected to be generated, and of sufficient strength and thickness to prevent collapse under the pressures exerted by overlying wastes and any waste cover materials or equipment used at the surface impoundment.

NR 664.0221(3)(b)4. 4. Designed and operated to minimize clogging during the active life and long-term care period.

NR 664.0221(3)(b)5. 5. Constructed with sumps and liquid removal methods (e.g., pumps) of sufficient size to collect and remove liquids from the sump and prevent liquids from backing up into the drainage layer. Each unit shall have its own sump. The design of each sump and removal system shall provide a method for measuring and recording the volume of liquids present in the sump and of liquids removed.

NR 664.0221(3)(c) (c) The owner or operator shall collect and remove pumpable liquids in the sumps to minimize the head on the bottom liner.

NR 664.0221(3)(d) (d) The owner or operator of a leak detection system that is not located completely above the seasonal high water table shall demonstrate that the operation of the leak detection system will not be adversely affected by the presence of groundwater.

NR 664.0221(4) (4) The department may approve alternative design or operating practices to those specified in sub. (3) if the owner or operator demonstrates to the department that the design and operating practices, together with location characteristics, will do both of the following:

NR 664.0221(4)(a) (a) Prevent the migration of any hazardous constituent into the groundwater or surface water at least as effectively as the liners and leachate collection and removal system specified in sub. (3).

NR 664.0221(4)(b) (b) Allow detection of leaks of hazardous constituents through the top liner at least as effectively.

NR 664.0221(5) (5) The double liner requirement in sub. (3) may be waived by the department for any monofill, if the requirements of pars. (a) and (b) 1. or 2. are met:

NR 664.0221(5)(a) (a) The monofill contains only hazardous wastes from foundry furnace emission controls or metal casting molding sand, and the wastes do not contain constituents which would render the wastes hazardous for reasons other than the toxicity characteristic in s. NR 661.0024.

NR 664.0221(5)(b) (b)

NR 664.0221(5)(b)1. 1. All of the following:

NR 664.0221(5)(b)1.a. a. The monofill has at least one liner for which there is no evidence that the liner is leaking. For the purposes of this subsection, the term “liner” means a liner designed, constructed, installed and operated to prevent hazardous waste from passing into the liner at any time during the active life of the facility, or a liner designed, constructed, installed and operated to prevent hazardous waste from migrating beyond the liner to adjacent subsurface soil, groundwater or surface water at any time during the active life of the facility. In the case of any surface impoundment which has been exempted from the requirements of sub. (3) on the basis of a liner designed, constructed, installed and operated to prevent hazardous waste from passing beyond the liner, at the closure of the impoundment, the owner or operator shall remove or decontaminate all waste residues, all contaminated liner material and contaminated soil to the extent practicable. If all contaminated soil is not removed or decontaminated, the owner or operator of the impoundment will comply with appropriate long-term care requirements, including but not limited to groundwater monitoring and corrective action.

NR 664.0221(5)(b)1.b. b. The monofill is located more than one-quarter mile from an underground source of drinking water (as that term is defined in 40 CFR 144.3).

NR 664.0221(5)(b)1.c. c. The monofill is in compliance with generally applicable groundwater monitoring requirements for facilities with operating licenses under s. 291.25, Stats.

NR 664.0221(5)(b)2. 2. The owner or operator demonstrates that the monofill is located, designed and operated so as to assure that there will be no migration of any hazardous constituent into groundwater or surface water at any future time.

NR 664.0221(6) (6) The owner or operator of any replacement surface impoundment unit is exempt from sub. (3) if both of the following apply:

NR 664.0221(6)(a) (a) The existing unit was constructed in compliance with the design standards of 42 USC 6924(o)(1)(A)(i) and (5).

NR 664.0221(6)(b) (b) There is no reason to believe that the liner is not functioning as designed.

NR 664.0221(7) (7) A surface impoundment shall be designed, constructed, maintained and operated to prevent overtopping resulting from normal or abnormal operations; overfilling; wind and wave action; rainfall; run-on; malfunctions of level controllers, alarms and other equipment and human error.

NR 664.0221(8) (8) A surface impoundment shall have dikes that are designed, constructed and maintained with sufficient structural integrity to prevent massive failure of the dikes. In ensuring structural integrity, it may not be presumed that the liner system will function without leakage during the active life of the unit.

NR 664.0221(9) (9) The department shall specify in the operating license all design and operating practices that are necessary to ensure that the requirements of this section are satisfied.

NR 664.0221 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06; CR 19-082: am. (5) (a) Register August 2020 No 776, eff. 9-1-20.

NR 664.0222 NR 664.0222 Action leakage rate.

NR 664.0222(1) (1) The department shall approve an action leakage rate for surface impoundment units subject to s. NR 664.0221 (3) or (4). The action leakage rate is the maximum design flow rate that the leak detection system can remove without the fluid head on the bottom liner exceeding one foot. The action leakage rate shall include an adequate safety margin to allow for uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of drainage material), construction, operation and location of the leak detection system, waste and leachate characteristics, likelihood and amounts of other sources of liquids in the leak detection system and proposed response actions (e.g., the action leakage rate shall consider decreases in the flow capacity of the system over time resulting from siltation and clogging, rib layover and creep of synthetic components of the system, overburden pressures, etc.).

NR 664.0222(2) (2) To determine if the action leakage rate has been exceeded, the owner or operator shall convert the weekly or monthly flow rate from the monitoring data obtained under s. NR 664.0226 (4) to an average daily flow rate (gallons per acre per day) for each sump. Unless the department approves a different calculation, the average daily flow rate for each sump shall be calculated weekly during the active life and closure period, and if the unit is closed in accordance with s. NR 664.0228 (2), monthly during the long-term care period when monthly monitoring is required under s. NR 664.0226 (4).

NR 664.0222 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06.

NR 664.0223 NR 664.0223 Response actions.

NR 664.0223(1) (1) The owner or operator of surface impoundment units subject to s. NR 664.0221 (3) or (4) shall have an approved response action plan before receipt of waste. The response action plan shall set forth the actions to be taken if the action leakage rate has been exceeded. At a minimum, the response action plan shall describe the actions specified in sub. (2).

NR 664.0223(2) (2) If the flow rate into the leak detection system exceeds the action leakage rate for any sump, the owner or operator shall do all of the following:

NR 664.0223(2)(a) (a) Notify the department in writing of the exceedence within 7 days of the determination.

NR 664.0223(2)(b) (b) Submit a preliminary written assessment to the department within 14 days of the determination, as to the amount of liquids, likely sources of liquids, possible location, size and cause of any leaks and short-term actions taken and planned.

NR 664.0223(2)(c) (c) Determine to the extent practicable the location, size and cause of any leak.

NR 664.0223(2)(d) (d) Determine whether waste receipt should cease or be curtailed, whether any waste should be removed from the unit for inspection, repairs or controls and whether or not the unit should be closed.

NR 664.0223(2)(e) (e) Determine any other short-term and longer-term actions to be taken to mitigate or stop any leaks.

NR 664.0223(2)(f) (f) Within 30 days after the notification that the action leakage rate has been exceeded, submit to the department the results of the analyses specified in pars. (c), (d) and (e), the results of actions taken and actions planned. Monthly thereafter, as long as the flow rate in the leak detection system exceeds the action leakage rate, the owner or operator shall submit to the department a report summarizing the results of any remedial actions taken and actions planned.

NR 664.0223(3) (3) To make the leak and remediation determinations in sub. (2) (c), (d) and (e), the owner or operator shall comply with par. (a) or (b):

NR 664.0223(3)(a) (a) Do all of the following:

NR 664.0223(3)(a)1. 1. Assess the source of liquids and amounts of liquids by source.

NR 664.0223(3)(a)2. 2. Conduct a fingerprint, hazardous constituent or other analyses of the liquids in the leak detection system to identify the source of liquids and possible location of any leaks, and the hazard and mobility of the liquid.

NR 664.0223(3)(a)3. 3. Assess the seriousness of any leaks in terms of potential for escaping into the environment.

NR 664.0223(3)(b) (b) Document why the assessments are not needed.

NR 664.0223 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06.

NR 664.0226 NR 664.0226 Monitoring and inspection.

NR 664.0226(1) (1) During construction and installation, liners (except in the case of existing portions of surface impoundments exempt from s. NR 664.0221 (1)) and cover systems (e.g., membranes, sheets or coatings) shall be inspected for uniformity, damage and imperfections (e.g., holes, cracks, thin spots or foreign materials). Both of the following inspections are required immediately after construction or installation:

NR 664.0226(1)(a) (a) Synthetic liners and covers shall be inspected, to ensure tight seams and joints and the absence of tears, punctures or blisters.

NR 664.0226(1)(b) (b) Soil-based and admixed liners and covers shall be inspected for imperfections including lenses, cracks, channels, root holes or other structural non-uniformities that may cause an increase in the permeability of the liner or cover.

NR 664.0226(2) (2) While a surface impoundment is in operation, it shall be inspected weekly and after storms to detect evidence of any of the following:

NR 664.0226(2)(a) (a) Deterioration, malfunctions or improper operation of overtopping control systems.

NR 664.0226(2)(b) (b) Sudden drops in the level of the impoundment’s contents.

NR 664.0226(2)(c) (c) Severe erosion or other signs of deterioration in dikes or other containment devices.

NR 664.0226(3) (3) Prior to the issuance of an operating license, and after any extended period of time (at least 6 months) during which the impoundment was not in service, the owner or operator shall obtain a certification from a qualified engineer that the impoundment’s dike, including that portion of any dike which provides freeboard, has structural integrity. The certification shall establish, in particular, that the dike will do both of the following:

NR 664.0226(3)(a) (a) Withstand the stress of the pressure exerted by the types and amounts of wastes to be placed in the impoundment.

NR 664.0226(3)(b) (b) Not fail due to scouring or piping, without dependence on any liner system included in the surface impoundment construction.

NR 664.0226(4) (4) 

NR 664.0226(4)(a) (a) An owner or operator required to have a leak detection system under s. NR 664.0221 (3) or (4) shall record the amount of liquids removed from each leak detection system sump at least once each week during the active life and closure period.

NR 664.0226(4)(b) (b) After the final cover is installed, the amount of liquids removed from each leak detection system sump shall be recorded at least monthly. If the liquid level in the sump stays below the pump operating level for 2 consecutive months, the amount of liquids in the sumps shall be recorded at least quarterly. If the liquid level in the sump stays below the pump operating level for 2 consecutive quarters, the amount of liquids in the sumps shall be recorded at least semi-annually. If at any time during the long-term care period the pump operating level is exceeded at units on quarterly or semi- annual recording schedules, the owner or operator shall return to monthly recording of amounts of liquids removed from each sump until the liquid level again stays below the pump operating level for 2 consecutive months.

NR 664.0226(4)(c) (c) “Pump operating level” is a liquid level proposed by the owner or operator and approved by the department based on pump activation level, sump dimensions and level that avoids backup into the drainage layer and minimizes head in the sump.

NR 664.0226 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06.

NR 664.0227 NR 664.0227 Emergency repairs; contingency plans.

NR 664.0227(1) (1) A surface impoundment shall be removed from service in accordance with sub. (2) when either of the following occurs:

NR 664.0227(1)(a) (a) The level of liquids in the impoundment suddenly drops and the drop is not known to be caused by changes in the flows into or out of the impoundment.

NR 664.0227(1)(b) (b) The dike leaks.

NR 664.0227(2) (2) When a surface impoundment must be removed from service as required by sub. (1), the owner or operator shall do all of the following:

NR 664.0227(2)(a) (a) Immediately shut off the flow or stop the addition of wastes into the impoundment.

NR 664.0227(2)(b) (b) Immediately contain any surface leakage which has occurred or is occurring.

NR 664.0227(2)(c) (c) Immediately stop the leak.

NR 664.0227(2)(d) (d) Take any other necessary steps to stop or prevent catastrophic failure.

NR 664.0227(2)(e) (e) If a leak cannot be stopped by any other means, empty the impoundment.

NR 664.0227(2)(f) (f) Notify the department of the problem in writing within 7 days after detecting the problem.

NR 664.0227(3) (3) As part of the contingency plan required in subch. D, the owner or operator shall specify a procedure for complying with the requirements of sub. (2).