Current through Register Vol. 48, No. 38, September 20, 2024
a) All units
shall be equipped with a leachate drainage and collection system and a
compacted earth liner designed as an integrated system in compliance with the
requirements of this Section and of Sections
811.307
and
811.308.
b) The liner and leachate collection system
shall be stable during all phases of construction and operation. The side
slopes shall achieve a minimum static safety factor of 1.3 and a minimum
seismic safety factor of 1.0 at all times.
c) The liner shall be designed to function
for the entire design period.
d)
Compacted Earth Liner Standards
1) The
minimum allowable thickness shall be 1.52 meters (5 feet).
2) The liner shall be compacted to achieve a
maximum hydraulic conductivity of 1 X 10-7
centimeters per second.
3) The
construction and compaction of the liner shall be carried out in accordance
with the construction quality assurance procedures of Subpart E so as to reduce
void spaces and allow the liner to support the loadings imposed by the waste
disposal operation without settling that causes or contributes to the failure
of the leachate collection system.
4) The liner shall be constructed from
materials whose properties are not affected by contact with the constituents of
the leachate expected to be produced.
5) Alternative specifications, using standard
construction techniques, for hydraulic conductivity and liner thickness may be
utilized under the following conditions:
A)
The liner thickness shall be no less than 1.52 meter (5 feet) unless a
composite liner consisting of a geomembrane immediately overlying a compacted
earth liner is installed. The following minimum standards shall apply for a
composite liner:
i) the geomembrane shall be
no less than 60 mils in thickness and meet the requirements of subsection (e);
and
ii) the compacted earth liner
shall be no less than 0.91 meter in thickness (3 feet) and meet the
requirements of subsection (d)(2) through (d)(4).
B) The modified liner shall operate in
conjunction with a leachate drainage and collection system to achieve
equivalent or superior performance to the requirements of this subsection.
Equivalent performance shall be evaluated at maximum annual leachate flow
conditions.
e) Geomembrane Liners
1) Geomembranes may be used only in
conjunction with a compacted earth liner system meeting the requirements of
subsection (d) and a leachate drainage and collection system meeting the
requirements of Sections
811.307
and 811.308.
2) The geomembrane
shall be supported by a compacted base free from sharp objects. The geomembrane
shall be chemically compatible with the supporting soil materials.
3) The geomembrane material shall be
compatible with the leachate expected to be generated.
4) Geomembranes shall have sufficient
strength and durability to function at the site for the design period under the
maximum expected loadings imposed by the waste and equipment and stresses
imposed by settlement, temperature, construction and operation.
5) Seams shall be made in the field according
to the manufacturer's specifications. All sections shall be arranged so that
the use of field seams is minimized and seams are oriented in the direction
subject to the least amount of stress.
6) The leachate collection system shall be
designed to avoid loss of leachate through openings in the
geomembrane.
f) Slurry
Trenches and Cutoff Walls Used to Prevent Migration of Leachate
1) Slurry trenches and cutoff walls built to
contain leachate migration shall be used only in conjunction with a compacted
earth liner and a leachate drainage system meeting the requirements of
subsection (d) and Section
811.307
or as part of a remedial action required by Section
811.319.
2) Slurry trenches and cutoff walls shall
extend into the bottom confining layer to a depth that will establish and
maintain a continuous hydraulic connection and prevent seepage.
3) Exploration borings shall be drilled along
the route of the slurry trench or cutoff wall to confirm the depth to the
confining layer. In situ tests shall be conducted to determine the hydraulic
conductivity of the confining layer.
4) Slurry trenches and cutoff walls shall be
stable under all conditions during the design period of the facility. They
shall not be susceptible to displacement or erosion under stress or hydraulic
gradient.
5) Slurry trenches and
cutoff walls shall be constructed in conformance to a construction quality
assurance plan, pursuant to Subpart E, that insures that all material and
construction methods meet design specifications.
g) The owner or operator may utilize liner
configurations other than those specified in this Section, special construction
techniques and admixtures provided that:
1)
The alternative technology or material provides equivalent, or superior,
performance to the requirements of this Section;
2) The technology or material has been
successfully utilized in at least one application similar to the proposed
application; and
3) Methods for
manufacturing quality control and construction quality assurance can be
implemented.