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.
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.
The pipe in the borehole shall be a minimum 6 inch diameter, Schedule 80 polyvinylchloride or an approved alternate.
The lower 2/3 to 3/4 of the pipe in the borehole shall be slotted or perforated pipe.
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.
Each gas extraction well shall have a flow control valve and sampling access port.
The gas header system shall be looped to allow alternative flow paths for the gas.
The minimum slope on the header pipe shall be 2% for pipes over the waste mass.
Polyethylene pipe shall be used for header and lateral pipes.
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.
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.
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.
The system shall be designed to have the ability to collect and treat all condensate, measure volumes and collect samples.
(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
(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
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.
Storm water management and miscellaneous design and construction criteria for landfills. 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.
All landfills shall incorporate the following concepts in the design of both temporary and permanent erosion and sediment control measures:
Grading and construction shall be scheduled to minimize soil exposure.
Runoff shall be diverted away from disturbed areas and active fill areas.
Drainageways and outlets shall be prepared to handle concentrated or increased runoff.
The design calculations required in pars. (d)
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.
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.
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.
Storm water shall be diverted away from the active fill area of the landfill and any borrow areas to a sedimentation control structure.
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
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.
Storm water diversion and construction at a landfill shall be designed to minimize impacts on adjacent property, such as erosion, sedimentation and flooding.
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.
All landfills shall be designed to meet the following requirements:
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.
Access to the landfill shall be restricted through the use of fencing, natural barriers or other methods approved in writing by the department.
All access roads for the landfill, including those leading to the active area, shall be designed for all weather operation.
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.
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.
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.
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.
A minimum of 2 leachate head wells shall be proposed for each major horizontal phase of the landfill unless otherwise approved by the department.
All landfills which accept municipal solid waste shall be supplied with a weight scale.
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
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.
Design criteria for landfills that recirculate leachate. NR 504.095(1)(1)
Leachate recirculation systems shall be designed to meet the following requirements:
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
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.
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.
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.
A minimum depth of 20 feet of waste shall be maintained between the landfill base and lowest point of leachate distribution.
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.
(2) Surface application.
In addition to the general requirements, surface application systems for leachate recirculation shall meet the following requirements:
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.
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.
(3) Vertical distribution systems.
Vertical distribution systems for leachate recirculation shall meet the following requirements:
Wells designed solely for the gas extraction system shall not be used for leachate recirculation.
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
. 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.
Leachate distribution wells shall be designed with a surface seal to control odors and landfill gas.
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.
The leachate distribution system shall be designed to achieve a uniform distribution of leachate throughout the zone of influence of the wells.
Leachate distribution wells may be designed to also extract landfill gas.
(4) Horizontal distribution systems.
Horizontal distribution systems shall meet the following requirements:
The leachate distribution piping shall be designed to distribute the leachate consistently along its length.
Distribution systems shall be designed with a permeable bedding material that is capable of rapidly dissipating recirculated leachate into the waste mass.
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.
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.
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.
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.
An applicant may design a high volume industrial waste landfill to meet the standards contained in ss. NR 504.05
or may propose an alternative design in accordance with the provisions of this section.
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.
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)
(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:
Landfill characteristics including regional and specific information on land use, geology, hydrology, hydrogeology and soils.
Waste characteristics including quantity and physical and chemical analyses of the waste and its leachate.
An analysis of any design to control geologic or hydrogeologic conditions of the site.
Design and performance data for other similarly designed and constructed landfills.
Accepted scientific or engineering analyses or field studies, field plots, research, manufacturer's data or demonstrations.
(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
Cr. Register, June, 1996, No. 486
, eff. 7-1-96.