Chapter NR 504

NR 504.095 NR 504.095 Design criteria for landfills that recirculate leachate.

NR 504.095(1) (1) General. Leachate recirculation systems shall be designed to meet the following requirements:

NR 504.095(1)(a) (a) Leachate recirculation shall be limited to municipal solid waste landfills that are designed with a composite liner and leachate collection system meeting the minimum requirements of s. NR 504.06.

NR 504.095(1)(b) (b) Leachate recirculation shall be limited to areas of the landfill where the leachate collection drainage blanket has a hydraulic conductivity of 1 cm/sec or greater. The department may approve leachate recirculation in existing cells with lower permeability leachate collection blankets, provided that the operator can demonstrate that the maximum leachate head on the liner can be maintained at less than 12 inches and that the recorded leachate head has not exceeded 12 inches in the past.

NR 504.095(1)(c) (c) Leachate shall be recirculated only in areas of the landfill which are connected to the active gas extraction systems and are capable of collecting the additional gas expected to be generated. Active gas extraction shall commence in those areas no later than the initiation of leachate recirculation.

NR 504.095(1)(d) (d) Leachate recirculation distribution systems may not discharge leachate within 100 lateral feet of the exterior sideslope final grades unless otherwise approved by the department in writing.

NR 504.095(1)(e) (e) A minimum depth of 20 feet of waste shall be maintained between the landfill base and lowest point of leachate distribution.

NR 504.095(1)(f) (f) Operating controls and instructions for leachate recirculation distribution systems shall be prepared to apply to operations expected to be encountered in all weather and seasons. Instructions shall include cessation of leachate recirculation upon discovery of seeps and other surface expressions of recirculated leachate, excessive pressures within the waste mass, saturated conditions in the waste mass, inadequate shear strength of the waste mass or other conditions indicative of instability.

NR 504.095(2) (2) Surface application. In addition to the general requirements, surface application systems for leachate recirculation shall meet the following requirements:

NR 504.095(2)(a) (a) The leachate distribution system shall be designed so that leachate is not introduced into the waste in a manner that causes ponding or surface runoff of leachate. Open surface trenches or ponds shall not be utilized.

NR 504.095(2)(b) (b) The leachate distribution system shall be designed to minimize evaporation of the leachate and volatilization of compounds in leachate. The leachate distribution system shall be designed to distribute the leachate in a manner that results in its absorption into the waste mass after application. Spray irrigation systems that are designed to promote evaporation may not be utilized.

NR 504.095(3) (3) Vertical distribution systems. Vertical distribution systems for leachate recirculation shall meet the following requirements:

NR 504.095(3)(a) (a) Wells designed solely for the gas extraction system shall not be used for leachate recirculation.

NR 504.095(3)(b) (b) Vertical distribution systems shall utilize vertical wells placed into the waste mass. Distribution well design need not comply with the requirements of s. NR 504.08 (1) or ch. NR 141 or 812. Well spacing shall be determined based on leachate flow rates, pumping characteristics, permeability of the waste mass, and ability of the waste to accept liquid without being pressurized.

NR 504.095(3)(c) (c) Leachate distribution wells shall be designed with a surface seal to control odors and landfill gas.

NR 504.095(3)(d) (d) Pumping pressures and pumping intervals for distribution wells shall be designed to prevent surface emergence of leachate. Pumping pressures and hydrostatic pressures shall be limited to prevent excessive pressures to prevent separation of waste layers or short-circuiting of leachate to the leachate collection system.

NR 504.095(3)(e) (e) The leachate distribution system shall be designed to achieve a uniform distribution of leachate throughout the zone of influence of the wells.

NR 504.095(3)(f) (f) Leachate distribution wells may be designed to also extract landfill gas.

NR 504.095(4) (4) Horizontal distribution systems. Horizontal distribution systems shall meet the following requirements:

NR 504.095(4)(a) (a) The leachate distribution piping shall be designed to distribute the leachate consistently along its length.

NR 504.095(4)(b) (b) Distribution systems shall be designed with a permeable bedding material that is capable of rapidly dissipating recirculated leachate into the waste mass.

NR 504.095(4)(c) (c) Distributions systems shall be designed with bedding material which is capable of maintaining its structure and characteristics during the expected operational life of the system.

NR 504.095(4)(d) (d) Distribution systems shall be designed to operate with specific distribution periods with landfill gas extracted in the interval between those distribution periods, unless otherwise approved by the department in writing. The length of the leachate distribution periods and the intervals of gas extraction shall be determined in a manner that minimizes uncontrolled landfill gas emissions.

NR 504.095(4)(e) (e) Pumping pressures and pumping intervals shall be designed to prevent surface emergence of leachate. Pumping pressures shall be limited to prevent excessive pressures to prevent separation of waste layers or seeps or other leachate discharges.

NR 504.095 History History: CR 04-077: cr. Register November 2005 No. 599, eff. 12-1-05; CR 06-026: am. (1) (d) and (2) (b), Register December 2006 No. 612, eff. 1-1-07.

NR 504.10 NR 504.10 Alternative design criteria for landfills accepting high volume industrial wastes. This section applies to landfills designed principally for high volume industrial waste, wood residue and minor amounts of other wastes as approved by the department. This section applies to all new landfills and to the expansion of existing landfills for which the plan of operation was approved after February 1, 1988. This section also applies to new and existing CCR landfills and lateral expansions of a CCR landfill.

NR 504.10(1) (1) General.

NR 504.10(1)(a) (a) An applicant may design a high volume industrial waste landfill to meet the standards contained in ss. NR 504.05 to 504.09 or may propose an alternative design in accordance with the provisions of this section.

NR 504.10(1)(b) (b) If the applicant does not complete construction of the first major phase of the landfill within 2 years from the date of the plan of operation approval, the applicant shall reapply to the department for approval to construct the landfill. This application does not constitute a feasibility report as defined in s. 289.24, Stats. The department may require additional conditions of approval and require redesign of the landfill in accordance with state-of-the-art design criteria.

NR 504.10(1)(c) (c) An owner or operator of a landfill which is designed primarily for disposal of high volume industrial waste may accept up to 10% by weight of municipal waste such as packaging which is generated in conjunction with the manufacturing process, and not be subject to the design requirements of s. NR 504.05 (1). Household and plant waste not generated as a direct result of the manufacturing process such as office and cafeteria waste, may not be disposed of in a landfill which does not meet the requirements of s. NR 504.05 (1).

NR 504.10(2) (2) Design capacity. Design capacity shall be in accordance with s. NR 504.05 (3).

NR 504.10(3) (3) Design criteria. An applicant seeking approval of an alternative design under this section shall demonstrate in the feasibility report required in ch. NR 512 that the alternative design adequately protects public health, welfare and the environment and meets or exceeds the location and performance standards of s. NR 504.04. The applicant may include the following types of information as a part of such a demonstration:

NR 504.10(3)(a) (a) Landfill characteristics including regional and specific information on land use, geology, hydrology, hydrogeology and soils.

NR 504.10(3)(b) (b) Waste characteristics including quantity and physical and chemical analyses of the waste and its leachate.

NR 504.10(3)(c) (c) An analysis of any design to control geologic or hydrogeologic conditions of the site.

NR 504.10(3)(d) (d) Field demonstration data.

NR 504.10(3)(e) (e) Design and performance data for other similarly designed and constructed landfills.

NR 504.10(3)(f) (f) Accepted scientific or engineering analyses or field studies, field plots, research, manufacturer’s data or demonstrations.

NR 504.10(3)(g) (g) For new and existing CCR landfills and any lateral expansion of a CCR landfill, a demonstration that the alternative design meets the federal requirements located under 40 CFR part 257, Subpart D dated April 17, 2015 (80 FR 21468), as amended at 83 FR 36451, July 30, 2018.

NR 504.10 Note Note: The code of federal regulations may be obtained at www.ecfr.gov. Copies of 40 CFR part 257, Subpart D dated April 17, 2015 (80 FR 21468), as amended at 83 FR 36451, July 30, 2018 are available for inspection at the legislative reference bureau.

NR 504.10(4) (4) Approval criteria. The department shall approve the alternative design proposed by the applicant if the department determines to a reasonable degree of certainty that the alternative design adequately protects public health, welfare and the environment and meets or exceeds the location and performance standards of s. NR 504.04.

NR 504.10 History History: Cr. Register, June, 1996, No. 486, eff. 7-1-96; CR 21-076: am. (intro.), cr. (3) (g) Register July 2022 No. 799, eff. 8-1-22.

NR 504.11 NR 504.11 Minimum design and construction criteria for landfills accepting residue produced by burning municipal solid waste.

NR 504.11(1) (1) Applicability. This section applies to landfills designed for residue produced by the burning of municipal solid waste as approved by the department. This section applies to all new and existing landfills.

NR 504.11(2) (2) Landfill design criteria for residue produced by burning municipal solid waste.

NR 504.11(2)(a) (a) All landfills that accept municipal solid waste combustor residue that tests below the limits specified in s. NR 502.13 (6) (g) shall be designed as composite lined monofill cells according to the following criteria:

NR 504.11(2)(a)1. 1. The composite liner shall consist of a minimum 60 mil geomembrane overlying a minimum thickness of 4 feet of compacted clay meeting the specifications of s. NR 504.06.

NR 504.11(2)(a)2. 2. The leachate collection system shall be designed such that the leachate from the residue monofill cell can be sampled and collected separately from non-residue disposal areas.

NR 504.11(2)(a)3. 3. The department may approve alternate designs such as double liners if it finds that the design provides equivalent protection.

NR 504.11(2)(b) (b) All landfills that accept municipal solid waste combustor residue that exceeds the limits specified in s. NR 502.13 (6) (g) shall be designed as a double composite lined monofill cell according to the following criteria. The department may approve alternate designs if it finds that the design provides equivalent protection.

NR 504.11(2)(b)1. 1. The double composite liner shall be designed with 2 separate composite liners with each liner consisting of a minimum 60 mil geomembrane overlying a minimum thickness of 4 feet of compacted clay meeting the specifications of s. NR 504.06.

NR 504.11(2)(b)2. 2. The composite liners shall be separated by a leachate detection layer consisting of a minimum one foot layer of granular material.

NR 504.11(2)(b)3. 3. Separate leachate collection systems shall be designed above and between the composite liners. The leachate collection system shall be designed such that the leachate from the leachate detection layer can be sampled and collected separately from the upper leachate collection system and from the non-residue disposal areas.

NR 504.11(2)(c) (c) All landfills which accept municipal solid waste combustor residue shall be approved by the department in accordance with s. NR 514.07 (5) prior to accepting each specific residue waste stream.

NR 504.11 History History: Cr. Register, June, 1996, No. 486, eff. 7-1-96.

NR 504.12 NR 504.12 Minimum design and construction criteria for CCR landfills.

NR 504.12(1) (1) Applicability. In addition to ss. NR 504.04 to 504.10, applicable to all landfills or landfills accepting high volume industrial waste, this section includes design criteria that are applicable to the construction of a new or existing CCR landfill or a lateral expansion of a CCR landfill.

NR 504.12(2) (2) Run-on and run-off controls. An existing or new CCR landfill or any lateral expansion of a CCR landfill shall be designed, constructed, operated, and maintained with a run-off and run-on control system in accordance with the requirements under s. NR 504.09 (1) (f) and (g) and all of the following:

NR 504.12(2)(a) (a) A run-on control system shall prevent flow onto the active portion of the CCR landfill during the peak discharge from a 24-hour, 25-year storm.

NR 504.12(2)(b) (b) A run-off control system from the active portion of the CCR landfill shall collect and control, at a minimum, the water volume resulting from a 24-hour, 25-year storm.

NR 504.12(3) (3) Liner design.

NR 504.12(3)(a) (a) A new CCR landfill or a lateral expansion of a CCR landfill shall be designed, constructed, operated, and maintained with a composite liner that meets the requirements under s. NR 504.06 (2) and (3) and a leachate collection and removal system that meets the requirements under s. NR 504.06 (5). The composite liner shall consist of 2 components; the upper component shall consist of a nominal 60-mil or thicker geomembrane liner, and the lower component shall consist of a minimum 4-foot-thick layer of compacted clay. A GCL and soil barrier may be used in place of the clay layer of a composite liner in accordance with s. NR 504.06 (7). In addition to the minimum design and construction criteria for landfill liners and leachate collection systems under s. NR 504.06, the liner and leachate collection system shall meet all of the following:

NR 504.12(3)(a)1. 1. The leachate collection and removal system shall be designed, constructed, operated, and maintained to limit the leachate head level on the liner to one foot or less.

NR 504.12(3)(a)2. 2. The leachate collection and removal system shall be constructed of materials that exhibit all of the following properties:

NR 504.12(3)(a)2.a. a. Chemically resistant to the CCR and any non-CCR waste managed in the CCR landfill and the leachate expected to be generated.

NR 504.12(3)(a)2.b. b. Of sufficient strength and thickness to prevent collapse under the pressures exerted by overlying waste, waste cover materials, and equipment used at the CCR landfill.

NR 504.12(3)(a)3. 3. The leachate collection and removal system shall be designed and operated to minimize clogging during the active life and during the long-term care of the landfill.

NR 504.12(3)(a)4. 4. The geomembrane component of the liner shall be installed in direct and uniform contact with the compacted clay soil component.

NR 504.12(3)(a)5. 5. A liner that utilizes a GCL and soil barrier layer in accordance with s. NR 504.06 (7) shall be designed to have a liquid flow rate no greater than the liquid flow rate through 2 feet of compacted soil with a hydraulic conductivity of 1 x 10-7 cm/sec. The liquid flow rate comparison shall be made using the following equation, which is derived from Darcy’s Law for gravity flow through porous media:

Q/A = q = k (h/t + 1)

Where:

Q = flow rate (cubic centimeters / second).

A = surface area of the liner (squared centimeters).

q = flow rate per unit area (cubic centimeters / second / squared centimeter).

k = hydraulic conductivity of the liner (centimeters / second).

h = hydraulic head above the liner (centimeters).

t = thickness of the liner (centimeters).

NR 504.12(3)(b) (b) A new CCR landfill or a lateral expansion of a CCR landfill shall be designed and constructed with a subbase grade that is located no less than 5 feet above the upper limit of the uppermost aquifer, or shall demonstrate that there will not be an intermittent recurring or sustained hydraulic connection between any portion of the base of the CCR landfill and the uppermost aquifer due to normal fluctuations in groundwater elevations, including the seasonal high water table.

NR 504.12 Note Note: A new CCR landfill or lateral expansion of a CCR landfill is also required to comply with s. NR 504.06 (2) (b) or (4) for zone-of-saturation landfills. The definition of an uppermost aquifer can be found under s. NR 500.03 (246m).

NR 504.12(3)(c) (c) A new CCR landfill or a lateral expansion of a CCR landfill may not be constructed over a closed CCR surface impoundment.

NR 504.12(4) (4) Final cover system.

NR 504.12(4)(a) (a) A new or existing CCR landfill or a lateral expansion of a CCR landfill shall be designed and constructed with a final cover system that meets the requirements under s. NR 504.07.

NR 504.12(4)(b) (b) The owner or operator of a new or existing CCR landfill or a lateral expansion of a CCR landfill may propose an alternative final cover system design within a written closure plan in accordance with s. NR 504.10 and all of the following:

NR 504.12(4)(b)1. 1. The permeability of the final cover system shall be less than or equal to the permeability of any bottom liner system or natural subsoils present or shall be no greater than 1 x 10-5 cm/sec, whichever is less.

NR 504.12(4)(b)2. 2. The design of the final cover system shall include an infiltration layer that achieves an equivalent reduction in infiltration as the layers specified under s. NR 504.07 (4).

NR 504.12(4)(b)3. 3. The design of the final cover system shall include an erosion layer that provides equivalent protection from wind or water erosion as the topsoil layer specified under s. NR 504.07 (7).

NR 504.12(4)(b)4. 4. The disruption of the integrity of the final cover system shall be minimized through a design that accommodates settling and subsidence.

NR 504.12 History History: CR 21-076: cr. Register July 2022 No. 799, eff. 8-1-22.