NR 664.0220NR 664.0220 Applicability. This subchapter applies to owners and operators of facilities that use surface impoundments to treat, store or dispose of hazardous waste except as s. NR 664.0001 provides otherwise.

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(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)(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(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)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)(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)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)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.