S.C. Code Regs. § ch. 61, 61-107, 61-107.19, pt. V, subpt. I

Current through Register Vol. 48, No. 10, October 25, 2024

Subpart I - Leachate Recirculation

1. Leachate recirculation at Class Three Landfills shall be limited to facilities which meet the following criteria:

a. Leachate recirculation shall be allowed only in facilities that were designed and constructed with a minimum of a composite liner system or equivalent, and that comply with all requirements for a Class 3 Landfill.

b. Leachate recirculation shall be allowed only in facilities which have a leachate collection system capable of maintaining less than one foot of leachate head on the liner system at all times.

c. Leachate and gas condensate collected from the facility shall be the only liquids allowed for recirculation back into the landfill.

d. Leachate recirculation will not be allowed in an area of the footprint which exhibits evidence of significant leakage of the liner system. A buffer approved by the Department shall be maintained between the suspected leaking area and the area of leachate recirculation.

e. Leachate recirculation shall be allowed only at facilities which are designed and constructed to have final slopes which are no steeper than three to one.

f. The Class Three Landfill shall have sufficient storage capacity onsite to handle all leachate generated by the facility in the event leachate recirculation activities are suspended.

g. Contracts to handle the total leachate generated by the facility, or approved and permitted onsite treatment facilities capable of handling all leachate generated by the facility shall be maintained at all Class Three Landfills performing leachate recirculation.

h. The permittee shall have adequate landfill gas control measures in place at the start of leachate recirculation to control the migration of methane and to control the presence of any odors associated with leachate recirculation.

i. A minimum thickness of 30 feet of waste shall be placed in a new cell before leachate recirculation can begin.

2. Class Three landfills performing leachate recirculation shall maintain the following buffer distances from facility side slopes:

a. If leachate is applied to the landfill by way of spraying the leachate at the working face, at a minimum, a 50 foot buffer shall be maintained at all times.

b. If leachate is applied to the landfill by way of pumping into a trench system, at a minimum, a 100 foot buffer shall be maintained at all times.

c. If leachate is applied to the landfill by way of injecting the leachate into vertical wells installed into the waste, at a minimum, a 100 foot buffer shall be maintained at all times.

d. Other methods of leachate recirculation into the facility shall have buffer zones from side slopes approved by the Department.

e. The Department may require additional buffer distances should evidence exist that the current buffer zones are not sufficient to protect stability of the landfill, to prevent the outbreak of leachate seeps, or to otherwise protect human health and the environment.

3. Approval to perform leachate recirculation shall be requested by the facility and approved by the Department on an annual basis. Upon a request for annual renewal of approval to leachate recirculate, the facility shall submit to the Department the following information in the form of an annual report:

a. Analytical results from leachate testing for the parameters specified in Appendix VI;

b. A summary of daily leachate recirculation rates along with injection locations;

c. Monthly leachate recirculation system inspection records, training procedures, and notification procedures;

d. Monthly landfill leachate and gas generation rate (if applicable) results; and,

e. Any requests for modification to the leachate recirculation system.

4. If problems associated with leachate recirculation are identified, the permittee shall:

a. Take all steps necessary to ensure protection of human health and the environment; and,

b. Within seven days of detection of a problem with leachate recirculation, place in the operating record and submit to the Department a copy of all actions taken to remedy the problem, and any proposed changes to the leachate recirculation system to prevent future problems.

5. Engineering Report. In addition to the permitting requirements outlined for Class Three Landfills in this Part, the permit application shall contain, at a minimum, the following:

a. Engineering drawings with detailed plans of the landfill that clearly show in plan and cross-sectional views the following: each leachate injection well; pipe lines; pipe inverts; drainage envelopes; manholes; cleanouts; valves; sumps; other devices as needed for leachate injection and monitoring, if applicable; and, a proposed waste saturation profile;

b. An engineering report containing a description of the existing site conditions and an analysis of the proposed landfill. The report shall:

(1) Contain design calculations using waste shear strength at 100% saturation that demonstrate that all containment structures, including liners, leachate collection systems, and surface water control systems, are designed to resist the maximum horizontal acceleration in lithified earth material for the site. Class Three landfills shall have a minimum 1.7 safety factor against failure, where the soil conditions are complex and when available strength data do not provide a consistent, complete, or logical picture of the strength characteristics. Where the soil conditions are uniform and high quality strength data provides a consistent, complete, and logical picture of the strength characteristics as determined by the Department, a minimum 1.2 safety factor against failure shall be used.

(2) Specify the leachate application rate of the landfill in gallons per day, specify the current leachate generation rates, and list the number, types, and specifications of all necessary machinery and equipment needed to effectively operate the application system at the landfill.

(3) Contain liner and leachate collection system efficiencies calculated using an appropriate analytical or numerical assessment. The factors to be considered in the calculation of collection system efficiency shall include, at a minimum, the saturated hydraulic conductivity of the liner, the liner thickness, the saturated hydraulic conductivity of the leachate collection system, the leachate collection system porosity, the base slope of the liner and leachate collection and removal system interface, the maximum flow distance across the liner and leachate collection and removal system interface to the nearest leachate collection pipe, the estimated leachate generation, including both natural quantity and the approved injection rate. The estimated leachate generation shall be used to predict the static head of leachate on the liners, volume of leachate to be collected, and the volume of leachate that may permeate through the entire liner system on a monthly basis. This assessment shall also address the amount of leachate expected to be found in the leachate collection and removal system in gallons per acre per day.

(4) Contain a leachate recirculation operation and maintenance report for the landfill that includes, at a minimum, the following:

(a) A description of the project's personnel requirements, stating personnel responsibilities and duties including discussions for training and lines of authority at the landfill; and,

(b) A description of all machinery and equipment to be used at the landfill for leachate recirculation, their authorized uses, and safety features.

(5) Contain a contingency plan discussing the course of action to be taken in responding to fires, leachate seeps, leachate releases, and other pertinent situations.

(6) Contain a description of the method for collecting and controlling landfill gases based on calculations of the estimated landfill gas generation during life of the landfill.

(7) Contain a demonstration of adequate storage capacity for all leachate generated at the site.

(8) Contain analytical results from leachate testing for the parameters specified in Appendix VI. prior to the start of leachate recirculation at the site.

S.C. Code Regs. ch. 61, 61-107, 61-107.19, pt. V, subpt. I