Chapter NR 504

NR 504.075(7)(c) (c) An isopach map showing the thickness of acceptable soil.

NR 504.075(7)(d) (d) A description of the methods to be used for separating the acceptable soil from any unacceptable soil.

NR 504.075(7)(e) (e) A proposal for maintaining drainage and sedimentation control.

NR 504.075(7)(f) (f) All data obtained from the testing program.

NR 504.075(8) (8) Data presentation for other borrow sources. Submittals for soil borrow sources other than those used for clay and soil barrier layers shall include all of the following:

NR 504.075(8)(a) (a) Property boundaries shown on a topographic map with a scale of 1 inch = 500 feet and provided in a digital format acceptable to the department. The mapped area shall extend a minimum of 500 feet beyond the proposed borrow source.

NR 504.075(8)(b) (b) A proposal for maintaining drainage and sedimentation control.

NR 504.075(9) (9) Stormwater management. Submittals for soil borrow sources shall include a stormwater management plan that complies with the requirements of s. NR 504.09 (1) (a) to (f) and (h) to (j), unless the borrow source is subject to other permits with equivalent authority and requirements, such as a stormwater discharge permit or non-metallic mining reclamation permit.

NR 504.075(10) (10) Reclamation of borrow sites. Submittals for soil borrow sources shall include a reclamation plan detailing the actions to be taken to achieve successful reclamation of the borrow source.

NR 504.075(10)(a) (a) Reclamation plans for borrow sources on the property where the landfill is located shall specify a post-mining land use that is integrated with the existing and proposed drainage, surface water discharge requirements, grades and final use of the landfill. The reclamation plan shall be prepared consistent with the applicable standards in ss. NR 135.06 to 135.12.

NR 504.075(10)(b) (b) Soil borrow areas that are not on the landfill property are subject to the provisions of ch. NR 135 and, if required, shall submit a reclamation plan and obtain a nonmetallic mining reclamation permit from the appropriate regulatory authority.

NR 504.075(11) (11) Other requirements.

NR 504.075(11)(a) (a) Clay borrow sources and soil barrier layer sources proposed for a liner or final cover that have less than a 5 foot but greater than 2 foot uniform thickness may be approved if the applicant demonstrates an excavation methodology and a documentation procedure to ensure that all soil used meets soil index properties required by this chapter.

NR 504.075(11)(b) (b) Submittals for soil borrow sources shall include a description of any necessary measures to be taken to comply with wetlands protection requirements, runoff and sediment controls and surface water discharge permit requirements and to minimize effects on areas of special natural resource interest and historical or archaeological areas within and adjacent to the proposed limits of excavation.

NR 504.075 Note Note: It may be necessary to obtain federal, state or local permits prior to excavating soil from a borrow source near surface waters or wetlands. For example, s. 30.19 (1g) (c), Stats., requires a permit for grading or removing top soil from the bank of any navigable stream, lake or body of navigable water where the area exposed by such grading or removal will exceed 10,000 square feet. It is the responsibility of the applicant or property owner to obtain any federal, state or local permits that are required and to provide reference to those other permit applications in the submittals for soil borrow sources.

NR 504.075 History History: CR 05-020: cr. Register January 2006 No. 601, eff. 2-1-06.

NR 504.08 NR 504.08 Minimum design and construction criteria for landfill gas extraction systems.

NR 504.08(1) (1) General. All landfills accepting wastes with the potential to generate gas shall be designed to prevent the migration of explosive gases generated by the waste fill.

NR 504.08(2) (2) Active gas extraction and treatment. In order to efficiently collect and combust hazardous air contaminants, all landfills which accept municipal solid waste shall be designed with an active gas recovery system. All gas recovery systems shall include the following design features, unless otherwise approved by the department:

NR 504.08(2)(a) (a) Vertical gas extraction wells shall be proposed throughout the entire landfill with a maximum radius of influence of 150 feet per well and lesser radii proposed for wells located near the perimeter of the landfill. The radii of influence of adjacent wells shall overlap. Alternate well spacings may be proposed if site specific data is obtained through performance of pump tests.

NR 504.08(2)(b) (b) All vertical gas extraction wells shall extend to 10 feet above the leachate collection system and shall be placed in 36 inch diameter boreholes. An exemption may be proposed to allow for placement of gas extraction wells closer to the leachate collection system.

NR 504.08(2)(c) (c) The pipe in the borehole shall be a minimum 6 inch diameter, Schedule 80 polyvinylchloride or an approved alternate.

NR 504.08(2)(d) (d) The lower 2/3 to 3/4 of the pipe in the borehole shall be slotted or perforated pipe.

NR 504.08(2)(e) (e) The backfill around the slotted or perforated pipe in the borehole shall be one to one and 1/2 inch washed stone. The top 10 feet of the borehole shall be sealed.

NR 504.08(2)(f) (f) Each gas extraction well shall have a flow control valve and sampling access port.

NR 504.08(2)(g) (g) The gas header system shall be looped to allow alternative flow paths for the gas.

NR 504.08(2)(h) (h) The minimum slope on the header pipe shall be 2% for pipes over the waste mass.

NR 504.08(2)(i) (i) Polyethylene pipe shall be used for header and lateral pipes.

NR 504.08(2)(j) (j) The sizing of the blower, header and laterals shall ensure that a minimum vacuum of 10 inches water column is available in the header adjacent to those wells located furthest from the blower.

NR 504.08(2)(k) (k) A drip leg or equivalent shall be installed immediately before the blower to separate condensate from gas while preserving the suction at the wells while under maximum operating vacuum.

NR 504.08(2)(L) (L) All condensate transfer piping and gas transfer piping located outside of the limits of waste shall be designed to be fully encased in at least 2 feet of clay, double-cased pipe or by using another approved secondary containment method except for systems with multiple drip legs within the landfill where the bulk of the condensate has been removed.

NR 504.08(2)(m) (m) The system shall be designed to have the ability to collect and treat all condensate, measure volumes and collect samples.

NR 504.08(2)(n) (n) A flare shall be designed to meet the requirements of ch. NR 445.

NR 504.08(3) (3) Gas monitoring wells. A minimum of one gas monitoring well shall be located on each side of the landfill. The wells shall be constructed according to s. NR 507.11.

NR 504.08(4) (4) Passive gas extraction systems. Landfills which accept only industrial waste or other nonmunicipal solid waste with the potential to generate gas and which do not utilize an active gas extraction system shall be designed with a system which allows gas venting from the entire landfill surface. An analysis shall be performed to determine the spacing needed between gas venting trenches for an effective system and also to ensure that ch. NR 445 limits for hazardous air contaminants will not be exceeded. The system shall be designed with a continuous layer below the capping layer which allows surficial venting from the waste final surface. This layer may be part of the support layer required in s. NR 504.07 (3). This layer shall consist of a minimum of one foot of granular soil with a minimum hydraulic conductivity of 1x10-3 cm/sec and a series of flexible, perforated pipes connected to a series of outlets.

NR 504.08 History History: Cr. Register, May, 1992, No. 437, eff. 6-1-92, r. and recr., Register, June, 1996, No. 486, eff. 7-1-96; CR 05-020: r. (2) (e) Register January 2006 No. 601, eff. 2-1-06.

NR 504.09 NR 504.09 Storm water management and miscellaneous design and construction criteria for landfills.

NR 504.09(1) (1) Storm water management.

NR 504.09(1)(a) (a) Storm water drainage ditches, structures and sedimentation basins shall be designed such that the construction of these items shall occur during the initial stage of construction to control rainfall runoff and limit entrained sediment from reaching surface water bodies.

NR 504.09(1)(b) (b) All landfills shall incorporate the following concepts in the design of both temporary and permanent erosion and sediment control measures:

NR 504.09(1)(b)1. 1. Grading and construction shall be scheduled to minimize soil exposure.

NR 504.09(1)(b)2. 2. Existing vegetation shall be retained whenever feasible.

NR 504.09(1)(b)3. 3. Disturbed areas shall be vegetated and mulched.

NR 504.09(1)(b)4. 4. Runoff shall be diverted away from disturbed areas and active fill areas.

NR 504.09(1)(b)5. 5. Runoff velocities shall be minimized.

NR 504.09(1)(b)6. 6. Drainageways and outlets shall be prepared to handle concentrated or increased runoff.

NR 504.09(1)(b)7. 7. Sediment shall be trapped on site.

NR 504.09(1)(b)8. 8. Runoff control structures shall be inspected and maintained.

NR 504.09(1)(c) (c) The design calculations required in pars. (d), (e) and (f) shall each be performed for the period in the landfill’s development where the combination of surface conditions and contributing acreage would result in the greatest runoff volume.

NR 504.09(1)(d) (d) All temporary and permanent storm water drainage ditches, swales, conveyance channels, channel linings, outlet protection, culverts and other storm water control structures handling flow onto or off the landfill shall be designed to accommodate peak flow rates from a 25 year, time of concentration storm event.

NR 504.09(1)(e) (e) Temporary and permanent sediment control measures shall be designed to settle 0.015 mm size particles for all storms up to and including the 25 year, 6-hour storm. The surface area for sediment basins shall be calculated using the rainfall intensity over the 25 year, 6-hour storm event for the landfill. Principal spillways, and outlet protection for sediment basins shall be designed to pass a 25 year, time of concentration storm event. Emergency spillways for sedimentation basins shall be designed to pass a 100 year, time of concentration storm event. The design of the dewatering structures for sediment basins shall be selected such that the basin is dewatered in no less than 3 days. An analysis shall be performed to document compliance with this requirement.

NR 504.09(1)(f) (f) Storm water shall be diverted away from the active fill area of the landfill and any borrow areas to a sedimentation control structure.

NR 504.09(1)(g) (g) Containment berms placed around active fill areas shall be designed to control and collect the liquid volume resulting from the 25 year, 24-hour storm event. The design shall consider the volume of liquid generated from active fill areas which shall include areas with exposed solid waste or areas with waste covered by daily cover. Storm water in contact with active fill areas shall be handled and treated as leachate in accordance with ch. NR 506.

NR 504.09(1)(h) (h) Storm water drainage ditches, structures and sedimentation basins shall discharge along existing drainage patterns capable of accepting the anticipated flow volume. An analysis shall be performed to determine the amount and velocity of runoff prior to landfill development and to document compliance with this requirement.

NR 504.09(1)(i) (i) Storm water diversion and construction at a landfill shall be designed to minimize impacts on adjacent property, such as erosion, sedimentation and flooding.

NR 504.09(1)(j) (j) Design of all storm water management features shall comply with other applicable requirements of the department. Such requirements include, but are not limited to, ch. NR 103, and permits required by ch. 30, Stats.

NR 504.09(2) (2) Miscellaneous. All landfills shall be designed to meet the following requirements:

NR 504.09(2)(a) (a) A method of controlling any dust or windblown debris shall be included in the landfill design. The factors which will be considered by the department when evaluating alternative provisions for controlling dust and windblown debris includes the remoteness of the landfill, natural screening, windbreaks and waste types.

NR 504.09(2)(b) (b) Access to the landfill shall be restricted through the use of fencing, natural barriers or other methods approved in writing by the department.

NR 504.09(2)(c) (c) All access roads for the landfill, including those leading to the active area, shall be designed for all weather operation.

NR 504.09(2)(d) (d) All access roads which are used by over the highway vehicles shall be designed with a maximum grade no greater than 10%. The intersection of the landfill access road with an existing highway shall be designed to provide sufficient sight distance and minimum interference with traffic on the highway.

NR 504.09(2)(f) (f) A minimum separation distance of 100 feet shall be maintained between the limits of filling and adjacent property line. A minimum distance of 50 feet shall be maintained between any permanent berms or excavations associated with the landfill, excluding storm water diversion structures and the adjacent property line.

NR 504.09(2)(g) (g) The landfill shall be designed so that final grades in each phase are reached as soon as possible, and the open area used for refuse filling is minimized.

NR 504.09(2)(h) (h) The final slopes of all landfills shall be equal to or greater than 5%, but may not exceed 4 horizontal to one vertical. Landfills primarily designed for the acceptance of papermill or wastewater treatment plant sludge shall have final slopes no greater than 6 horizontal to one vertical.

NR 504.09(2)(i) (i) A minimum of 2 leachate head wells shall be proposed for each major horizontal phase of the landfill unless otherwise approved by the department.

NR 504.09(2)(j) (j) All landfills which accept municipal solid waste shall be supplied with a weight scale.

NR 504.09(2)(k) (k) All landfills shall be designed with properly protected permanent benchmarks for horizontal and vertical control. Elevations shall be tied to USGS datum and horizontal control shall be referenced to the property boundary.

NR 504.09 History History: Cr. Register, June, 1996, No. 486, eff. 7-1-96; am. (1) (e), Register, September, 1998, No. 513, eff. 10-1-98; CR 05-020: r. (2) (e) Register January 2006 No. 601, eff. 2-1-06.

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.