Wisconsin Administrative Code
Department of Natural Resources
NR 500-599 - Environmental Protection - Solid Waste Management
Chapter NR 504 - Landfill Location, Performance, Design And Construction Criteria
Section NR 504.095 - Design criteria for landfills that recirculate leachate
Universal Citation: WI Admin Code ยง NR 504.095
Current through August 26, 2024
(1) GENERAL. Leachate recirculation systems shall be designed to meet the following requirements:
(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.
(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.
(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.
(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.
(e) A minimum depth of 20
feet of waste shall be maintained between the landfill base and lowest point of
leachate distribution.
(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.
(2) SURFACE APPLICATION. In addition to the general requirements, surface application systems for leachate recirculation shall meet the following requirements:
(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.
(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.
(3) VERTICAL DISTRIBUTION SYSTEMS. Vertical distribution systems for leachate recirculation shall meet the following requirements:
(a) Wells designed solely for
the gas extraction system shall not be used for leachate
recirculation.
(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.
(c) Leachate distribution wells shall be
designed with a surface seal to control odors and landfill gas.
(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.
(e) The leachate distribution system shall be
designed to achieve a uniform distribution of leachate throughout the zone of
influence of the wells.
(f)
Leachate distribution wells may be designed to also extract landfill
gas.
(4) HORIZONTAL DISTRIBUTION SYSTEMS. Horizontal distribution systems shall meet the following requirements:
(a) The leachate distribution
piping shall be designed to distribute the leachate consistently along its
length.
(b) Distribution systems
shall be designed with a permeable bedding material that is capable of rapidly
dissipating recirculated leachate into the waste mass.
(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.
(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.
(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.
Disclaimer: These regulations may not be the most recent version. Wisconsin may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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