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)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 under s. NR 670.002.

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(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 664.0222(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 664.0223(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)(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)(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.