(a) Applicability.

1. (1) The following are minimum design standards for Class 1 landfills that are located within the outcrop area of the Boone and St. Joe Formations.
2. (2) The design phase of a project must neutralize all limitations noted in the site characterization study through engineering modification or operating methods.
3. (3) The design of the containment structure must meet or exceed the minimum standards listed in this part.

(b) Separation requirements.

1. (1) A minimum separation of ten feet (10’) must be maintained between the bottom of the bottom liner system and the seasonal high water table surface.
2. (2) A minimum vertical separation of ten feet (10’) must be maintained between the bottom liner and the highest point of the bedrock or pinnacles.
3. (3) All fill structures and operations must be above the one hundred-year flood elevation.

(c) Liner system.

1. (1) The minimum slope on the bottom liner must ensure positive drainage of leachate after maximum loading and maximum expected strain.

2. (2)

   1. (A) All bottom liner systems must consist of a double composite separated by a leak detection system.
   2. (B) Each composite liner shall consist of an upper geomembrane liner, sixty (60) mil minimum thickness, directly overlying a low permeability soil layer, as described in 8 CAR § 60-424(b).
3. (3) The soil and synthetic components of the composite liner must meet the requirements of 8 CAR § 60-428.

(d) Leachate collection system.

1. (1) The double composite liner system must have a leachate removal system directly overlying the upper composite liner.

2. (2) In addition to the requirements of 8 CAR § 60-429, the leachate collection and removal system must meet the following standards:

   1. (A) The system must be designed such that leachate head above the primary composite liner does not exceed one foot (1’) under the most severe conditions anticipated;
   2. (B)

(d) (d) A minimum of twenty-four inches (24”) in thickness.

1. (ii) Equivalent drainage nets or fabric may be used in lieu of the twenty-four-inch drainage layer provided a substitute protective layer is provided and the system provides an equivalent hydraulic conductivity to the twenty-four-inch layer; and

   1. (C)

      1. (i) Leachate collection pipes must be incorporated into the drainage layer to convey liquid out of the landfill to storage tanks or a treatment system.
      2. (ii) The pipes must be a minimum of six inches (6”) in diameter and must be chemically compatible with the leachate generated at the landfill and be structurally capable of supporting the maximum static and dynamic load anticipated from the overlying fill material and construction equipment.

(e) Leak detection system.

1. (1) The double composite liner system must have a leak detection system located between the upper composite and the lower composite liners.

2. (2) The leak detection system must conform to the following standards:

   1. (A) The minimum thickness of the coarse grained material must be one foot (1’);

   2. (B)

      1. (i) Leak detection systems shall meet the standards for leachate collection system design and construction.
      2. (ii) A minimum hydraulic conductivity of 1 x 10^-3 cm/sec must be obtained in the leak detection system material;

   3. (C)

      1. (i) An action leakage rate must be developed for the design and approved by the Division of Environmental Quality.
      2. (ii) If leakage rates exceed the action leakage rate, fill operations must cease and the division must be notified.
      3. (iii) A written contingency plan must be developed for the facility which outlines steps and measures to be taken if the action leakage rate is exceeded; and
   4. (D) Daily records of fluid accumulation in the leak detection system must be maintained by the owner or operator.

(f) Final cover design.

1. (1) In addition to the requirements of 8 CAR § 60-1301, the top liner or cap of the landfill must be designed to minimize infiltration of storm water into the waste mass.

2. (2) The cover system design must incorporate the following minimum standards:

   1. (A)

      1. (i) A gas venting layer at least six inches (6”) in thickness that meets the standards for leachate collection system design and construction having a minimum hydraulic conductivity of 1 x 10^-3 cm/sec and no more than five percent (5%) by weight passing the #200 sieve, must be placed directly above the final lift of waste.
      2. (ii) Gas vent risers with slotted screen which extend at least three feet (3’) into the waste mass and fitted with a goose neck cap or equivalent to allow effective venting must be installed in the landfill.
      3. (iii) Vent spacing shall be a minimum of one (1) per acre.
      4. (iv) The annular space in the gas vent risers must be backfilled with clean crushed stone to enhance gas migration from the venting layer to the riser;

   2. (B)

      1. (i) A composite infiltration barrier system shall be installed above the gas venting layer.
      2. (ii) The barrier system shall consist of two (2) components:

(b) (b) The lower component consisting of at least an eighteen-inch layer of compacted soil with a hydraulic conductivity of no more than 1 x 10^-7 cm/sec.

1. (iii) The flexible membrane liner component must be installed in direct and uniform contact with the compacted soil component.

   1. (iv) The composite cover system shall be designed and constructed in accordance with the requirements of 8 CAR § 60-428 except that the fines content of the barrier layer soil must be fifty percent (50%) or greater passing the #200 sieve.

      1. (v) The barrier soil shall be free of large objects and must meet the following specifications:

(b) (b) Fines content of the barrier layer soil must be fifty percent (50%) or greater passing the #200 sieve;

1. (c) (c) Material greater than a #4 sieve must not compose more than twenty percent (20%) by weight of the soil; and

   1. (d) (d) No particles greater than one inch (1”) in diameter;

   2. (C)

      1. (i) A barrier protective layer must be placed directly over the barrier soil layer.
      2. (ii) This protective layer must be at least twenty-four inches (24”) in thickness and the lower six inches (6”) must be free of objects greater than one inch (1”) in diameter; and

   3. (D)

      1. (i) A top soil layer of at least six inches (6”) must be placed above the barrier soil protective layer.
      2. (ii) The top soil layer must be capable of sustaining vegetative growth over the landfill.

(g) Final cover slopes.

1. (1) Minimum slopes on the landfill cap shall be four percent (4%) or greater.
2. (2) Maximum slopes shall not exceed twenty-five percent (25%).
3. (3) Slopes greater than ten percent (10%) will require specialized erosion control measures which will ensure long-term stability.

(h) Vegetative cover.

1. (1) An appropriate grass cover crop must be established during the recommended planting season on completed portions of the landfill.

2. (2) The operating plan must contain a section describing in detail revegetation procedures.

   1. (i) Drainage filters.
3. (1) All granular drainage layers must be bounded above and below by geosynthetic liner or filters.
4. (2) The filter fabric must be compatible with leachate and landfill gas.
5. (3) The filters must allow free passage of gases and fluids while preventing clogging of the granular drainage layer.

(k) Quality assurance and quality control. A quality control and quality assurance plan for liner and final cover construction must be developed in accordance with the requirements of 8 CAR § 60-428.

1. (l) Quality assurance. The permittee shall employ a third-party engineering firm to ensure proper construction of each component of the containment structure in accordance with the requirements of 8 CAR § 60-428.