Alabama Administrative Code › Title 335 - ALABAMA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT › LAND DIVISION - SOLID WASTE PROGRAM › Chapter 335-13-4 - PERMIT REQUIREMENTS › Section 335-13-4-.18 - Liners and Leachate Collection

Current through Register Vol. 42, No. 9, June 28, 2024
(1)
Liners
. Where
				natural hydrogeologic conditions may be determined by the Department to be
				insufficient to minimize the impact of leachate on waters, the use of an
				appropriate liner(s) shall be used as approved by the Department. New MSWLF
				units and lateral expansions, at a minimum, shall be constructed with a
				composite liner, as defined in
				335-13-1-.03, or an alternate
				design as specified in
				335-13-4-.18(3)(h).
				Multiple liners, including composite liners, may be required if determined
				necessary by the Department.
(2)
Leachate Collection System
. A leachate collection
				system shall be required that is designed and constructed to maintain less than
				a 30 cm depth of leachate over the liner.
(3)
Specifications
.
				The composite liner(s) shall comply with the following minimum standards:
(a) The permeability shall be
				1x10-7 cm/sec or less for soil liners.
(b) The synthetic liner(s) shall be resistant
				to physical and chemical attack by leachate.
(c) The liner system shall be capable of
				maintaining integrity for the design life which must be determined on a site
				specific basis.
(d) The minimum
				allowable thickness of each layer of the composite liner shall be:
1. 40 mil for the flexible membrane liner
				component unless flexible membrane liner (FML) consists of high density
				polyethylene (HDPE) which requires 60 mil, and
2. Two feet, measured after compaction, for
				the natural soil liner component meeting the permeability requirements of
				335-13-4-.18(3)
				(a).
(e) The installation of synthetic liners
				shall be as recommended by the manufacturer providing that:
1. The installation recommendations of the
				manufacturer to be used are provided to the Department for review.
2. The Department finds that the recommended
				installation procedures are consistent with the intent of the Act and this
				chapter.
3. The installation of the
				liner shall be under the supervision of an engineer who shall certify to the
				Department that the liner was installed and maintained in accordance with this
				Division, QA/QC plans, and approved design plans.
(f) The design and installation of soil
				liners and the properties of soils used in a soil liner shall meet the
				following minimum requirements:
1. Design of
				soil liner(s) shall be by a qualified soils engineer, or geotechnical
				engineer.
2. The soil liner must be
				compacted in lifts of 4 to 6 inches within 4 percent of optimum moisture
				content (or as approved by the Department) to a field density which correlates
				with a laboratory permeability of 1x10-' cm/sec or less.
3. The installation of soil liner(s) shall be
				under the supervision of a soils engineer, geotechnical engineer or geologist
				who shall certify to the Department that the liner(s) was installed and
				maintained in accordance with this Division, QA/QC plans, and approved design
				plans.
4. The soils used in soil
				liners shall meet the minimum following criteria:
(i) Free of oversize particles, such as
				rocks, roots, limbs and other foreign substances which would alter the design
				integrity of the liner;
(ii)
				Classified under the Unified Soil Classification System as CL, CH or SC (ASTM
				Standard D2 487-69);
(iii) Allow
				greater than 30 percent passage through a No. 200 sieve (ASTM Test
				D-1140);
(iv) Have a liquid limit
				equal to or greater than 30 units (ASTM Test D-423); and
(v) Have a plasticity greater than or equal
				to 15 units (ASTM Test D-424).
(g) For a composite liner system, the
				synthetic liner shall be installed in direct contact with the soil
				liner.
(h) An alternate liner
				design may be approved by the Department provided that:
1. The owner or operator demonstrates that
				the alternate design ensures the concentration values listed in Table 1 of this
				rule will not be exceeded in the first saturated zone at the relevant point of
				compliance, as specified by the Department under
				335-13-4-.27(2)
				(a)3.
2. When approving a design that complies with
				subparagraph (a) of this paragraph, the Department shall consider at least the
				following factors:
(i) The hydrogeologic
				characteristics of the facility and surrounding land;
(ii) The climatic factors of the area;
				and
(iii) The volume and physical
				and chemical characteristics of the leachate.