Ala. Admin. Code r. 335-13-4-.18

Current through Register Vol. 43, No. 1, October 31, 2024

Section 335-13-4-.18 - Liners and Leachate Collection

(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.

TABLE 1

Chemical	MCL(mg/l)
Arsenic	0.05
Barium	1.0
Benzene	0.005
Cadmium	0.01
Carbon tetrachloride	0.005
Chromium (hexavalent)	0.05
2, 4-Dichlorophenoxy acetic acid	0.1
1, 4-Dichlorobenzene	0.075
1, 2-Dichloroethane	0.005
1, 1-Dichloroethylene	0.007
Endrin	0.0002
Fluoride	4
Lindane	0.004
Lead	0.015
Mercury	0.002
Methoxychlor	0.1
Nitrate	10
Selenium	0.01
Silver	0.05
Toxaphene	0.005
1, 1, 1-Trichloromethane	0.2
Trichloroethylene	0.005
2,4,5-Trichlorophenoxy acetic acid	0.01
Vinyl Chloride	0.002

Ala. Admin. Code r. 335-13-4-.18

November 18, 1981; Amended: July 21, 1988. Amended: Filed September 28, 1993; effective November 2, 1993. Amended: Filed June 21, 1996; effective July 26, 1996.

Amended by Alabama Administrative Monthly Volume XXXVI, Issue No. 07, April 30, 2018, eff. 6/8/2018.

Authors: Russell A. Kelly, S. Scott Story

Statutory Authority:Code of Ala. 1975, §§ 22-27-3, 22-27-7.