Code of Maine Rules
06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION
096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL
Chapter 854 - STANDARDS FOR HAZARDOUS WASTE FACILITIES
Section 096-854-9 - Additional Standards for Hazardous Waste Surface Impoundments

Universal Citation: 06 ME Code Rules ยง 096-854-9

Current through 2024-38, September 18, 2024

A. Performance Standards. A hazardous waste surface impoundment which is existing, new or laterally expanded must be established, constructed, altered and operated to meet the following performance standards:

(1) A surface impoundment must be designed, constructed, and installed to prevent any migration of wastes out of the impoundment to the adjacent subsurface soil or ground water or surface water at any time during the life, including the post-closure period, of the impoundment.

(2) An impounded hazardous waste or constituent or derivative thereof must not appear in ground water or surface water at a concentration above background level, or above current public health drinking water standards for Maine, including the "Maine CDC Maximum Exposure Guidelines (MEGs) for Drinking Water, December 31, 2016", or standards for aquatic toxicity, whichever is most stringent. Background levels must be those established by the preconstruction analysis required by 06-096 C.M.R. ch. 856, § 10(C)(10)(g) or of the upgradient monitoring well required by Section 8(D)(1) of this Chapter, whichever is lower.

NOTE: Drinking water and aquatic toxicity standards are obtained from current manuals including but not limited to: State of Maine Rules of the Department of Health and Human Services relating to Drinking Water; "Maine CDC Maximum Exposure Guidelines (MEGs) for Drinking Water, December 31, 2016"; "Drinking Water and Health" published by the National Research Council; "Suggested No-Adverse Response Levels (SNARLs)" as determined by the Environmental Protection Agency; "Ambient Water Quality Criteria" manuals, published by the Environmental Protection Agency.

(3) An impounded hazardous waste or constituent or derivative thereof must not appear in the atmosphere in concentrations significantly above the background level or exceed current ambient air quality standards for Maine at any time. Background levels must be established by monitoring or demonstrated to have been previously established by monitoring.

(4) An applicant seeking a license to treat hazardous waste in a surface impoundment must demonstrate to the satisfaction of the Board that:
(a) The waste is capable of being treated in a surface impoundment using the process proposed, based upon a trial test (a bench or small-scale pilot test) that determines the treatment technique, its effectiveness, and any limiting factors;

(b) The design measures and operating procedures will maximize the success of the treatment;

(c) The facility design and components are compatible with the hazardous waste and the treatment process; and

(d) The treatment process can and will be controlled at all times so as to prevent uncontrolled releases of hazardous waste or its constituents or derivatives and to protect the public health and safety and the environment.

B. Design. The facility must comply with the provisions of 40 C.F.R. §§264.221(c) and 264.221(g) -(i), in addition to the following:

(1) All new, replacement or expanded portions of a surface impoundment established in the State of Maine must be at least double-lined.

(2) A surface impoundment must have at least two impervious liners of or equivalent to:
(a) A synthetic top liner (e.g., geomembrane), which is underneath the impounded waste and is designed and constructed of materials to prevent the migration of hazardous constituents into such liner during the active life and post-closure care period; and

(b) A composite bottom liner, which is underneath the top synthetic liner and overtop the subsoils and consists of two components, including a synthetic upper component (e.g., geomembrane) designed and constructed of materials to prevent the migration of hazardous constituents into this component during the active life and post-closure care period and a lower component of recompacted clay of a minimum of ten (10) feet thick, with a hydraulic conductivity of 1 x 10-7 cm/sec or less. If a suitably low permeability clay lower component cannot be produced by recompaction, its permeability must be decreased by addition of bentonite or other approved sealing compounds.

NOTE: Proper siting on low permeability deposits is the single most important design criterion for hazardous waste surface impoundments. Siting in a favorable hydrologic setting is also an important design criterion, ground water discharge zones being considered most favorable.

(3) Where the surface impoundment is located in a ground water discharge zone, an applicant must evaluate the possibility of upward rupture of the liners and design the impoundment so as to prevent such a rupture.

(4) The liner system in contact with the impounded waste must be:
(a) Compatible with the waste;

(b) Sufficiently impermeable to the waste under maximum operating conditions of hydraulic head so that the leachate system would not be filled in a period of less than one year;

(c) Of sufficient strength to outlast the design lifetime of the impoundment; and

(d) Constructed on a foundation capable of supporting the liner and the pressure head of the impoundment when full.

(5) A leachate detection, collection and removal system must be installed immediately above the top synthetic liner to assure that leachate is collected and removed. In addition, a leachate detection, collection and removal system must be installed between the top synthetic liner and bottom composite liner.

(6) A leachate detection, collection and removal system must be constructed such that:
(a) The system immediately above the top synthetic liner must be designed, constructed, maintained, and operated to collect and remove leachate from the surface impoundment during the active life and post closure care period. The collection and removal system must be designed so that no more than 30 cm (1 foot) of leachate will accumulate on the top synthetic liner at any one time.

(b) The leachate collection system between the liners must be designed, constructed, maintained, and operated to detect, collect, and remove liquids that may leak through the top synthetic liner during the active life and post closure care period and meet the specifications for the action leakage rate approved for the impoundment in accordance with 40 C.F.R. §264.222.

The requirements for the leachate detection, collection, and removal system are satisfied by installation of a system that is, at a minimum:

(i) Constructed with a bottom slope of one percent or more;

(ii) Constructed of granular drainage material with a hydraulic conductivity of 1 x 10-1 cm/sec or more and a thickness of 12 inches or more; or constructed of synthetic or geonet drainage materials with a transmissivity of 3 x 10-4 m2 /sec or more;

(iii) Constructed of materials that are chemically resistant to the waste managed in the surface impoundment and the leachate expected to be generated and of sufficient strength and thickness to prevent collapse under the pressures exerted by overlying wastes, waste cover materials, and by any equipment used at the surface impoundment;

(iv) Designed and operated to function without clogging during the active life and post-closure care period; and

(v) Constructed with sumps and liquid removal methods (e.g., pumps) of sufficient size to collect and remove liquids from the sump and prevent liquids from backing up into the drainage layer. Each unit must have its own sump(s) and each sump and removal system must provide a method for measuring and recording the volume of liquids present and removed.

(7) Dikes must be designed with sufficient structural integrity to prevent failure when saturated, without dependence on any liner system for support.

(8) Earthen dikes must have a protective cover such as grass, shale or rock to minimize wind and water erosion and to preserve their structural integrity.

(9) Run-on must be diverted away from the surface impoundment.

(10) At least two feet of freeboard must be assured at all times.

(11) An automatic shutoff or automatic diversion system must be installed in the waste feed so that flow of waste into the impoundment will stop when there is less than 2 feet of freeboard or any failure of the base or liners.

(12) An automatic alarm system to alert the operator to abnormal operations and to malfunctions must be installed.

(13) A backup containment system must be provided to contain 20% of the volume of the impoundment or 4 hours maximum flow from the influent pipe(s), whichever is the larger amount.

(14) The applicant must evaluate the earthquake risk and must demonstrate that the facility is designed so that any disruption due to earthquake will not cause any performance standard to be violated.

(15) The applicant must evaluate the compaction and settlement beneath the liners and must demonstrate that the liners will not crack or rupture under full potential load. The applicant must comply with the construction quality assurance program requirements of Section 6(C)(7) of this Chapter and 40 C.F.R. §264.19, including quality assurance of construction design, structural stability and integrity of all components.

(16) A ground water monitoring system which meets the requirements of Section 8(D) of this Chapter must be operational before any waste is placed in the impoundment.

(17) Fugitive emissions, including volatile organic compounds, from the surface impoundment, must be controlled in accordance with a plan approved by the Board.

(18) Requirements other or less stringent than those established by Section 9(B)(1) -(13) of this Chapter may be imposed on a surface impoundment which is interimly licensed and being used for handling hazardous waste on the effective date of this Chapter, if the applicant demonstrates to the Board's satisfaction that the surface impoundment has not in the past violated the performance standards established herein and that the risk that it will violate the performance standards is no greater than that risk for a surface impoundment which meets the above requirements.

C. Operation

(1) A surface impoundment must have at all times sufficient freeboard to prevent overtopping by overfilling, wave action or a storm. At all times, there must not be less than 2 feet of freeboard.

(2) Leachate must be removed from the leachate collection system either continuously or with sufficient regularity that no hydraulic head builds up within it.
(a) An action leakage rate, representing the maximum design flow rate that the leak detection system can remove without fluid head on the bottom liner exceeding one foot, must be identified.

(b) Liquids removed from the leachate collection system must be recorded weekly and converted to an average daily flow rate in gallons per acre per day at each sump where liquid is removed and used to determine exceedances of the action leakage rate.

(c) Owners or operators must have an approved response action plan specifying response actions to be taken in the event the action leakage rate has been exceeded. The response action plan must comply with Section 9(D) of this Chapter and 40 C.F.R. §264.223.

(3) Earthen dikes must be kept free of perennial woody plants and burrowing animals and maintained to prevent any erosion of the dikes.

(4) The owner and operator must comply with the provisions of 40 C.F.R. §§264.229 - 264.231 except that the references to sections of 40 C.F.R. Part 261 shall mean the applicable sections of 06-096 C.M.R. ch. 850, references to 40 C.F.R. Part 268 shall mean the applicable sections of 06-096 C.M.R. ch. 852, and references to 40 C.F.R. §264.17(b) shall mean Section 6(C)(8) of this Chapter.

(5) The owner and operator must comply with the air emission standards of 40 C.F.R. §264.232.

D. Containment System Repairs: Contingency Plans

(1) Whenever there is any indication of a possible failure of the base, liner, dike, leachate collection system or backup containment system, that part or system must be inspected in accordance with the requirements of Section 9(D)(4) of this Chapter. Indications of possible failure include:
(a) An unplanned non-sudden drop in liquid level in the impoundment;

(b) Liquid detected in the leachate detection system above the quantity to be expected from the design permeability of the liner or an exceedance of the action leakage rate;

(c) Evidence of leakage or the potential for leakage in the dike;

(d) Erosion of the dike;

(e) Apparent or potential deterioration of the liner(s) based on observation or test samples of the liner materials;

(f) Any mishandling of wastes placed in the impoundment; and

(g) Foreign objects in the impoundment.

(2) Whenever there is an indication of a failure of the base, liner, dike or leachate collection system, the surface impoundment must be removed from service. Indications of failure of the containment system include but are not limited to:
(a) An unplanned sudden drop in liquid level in the impoundment;

(b) Quantities of waste detected in the leachate detection system in excess of three times the normal daily quantities or an exceedance of the action leakage rate;

(c) Leakage through the dike; or

(d) A breach (e.g., a hole, tear, crack, or separation) in the base, liner, dike, leachate collection or backup containment system.

(3) If the surface impoundment must be removed from service the owner or operator must:
(a) Immediately shut off the flow of or stop the addition of wastes into the impoundment;

(b) Immediately contain any leakage which has occurred or is occurring;

(c) Immediately stop any leakage; and

(d) If the leak cannot be stopped by any other means, empty the impoundment into secure containers or the backup containment system.

(e) Take any other steps necessary to stop or prevent catastrophic failure.

(f) Notify the Department of the problem verbally within 24 hours and in writing within seven days after detecting the problem.

NOTE: To report this situation, call the Department response phone number, 1-800-482-0777.

(4) The owner or operator must include as part of the contingency plan that is required to be filed with the application:
(a) A procedure for complying with the requirements of Section 9(D)(3) above; and

(b) A method for base, liner, dike, leachate collection and backup containment system evaluation and repair including:
(i) Testing and monitoring techniques;

(ii) Procedures to be followed to evaluate the integrity of the base, liner, dike, leachate collection system and backup containment system in the event of a possible failure;

(iii) Actions to be taken in the event of a possible failure; and

(iv) Specification of the repair techniques to be used in the event of leakage which does not require the impoundment to be removed from service.

(5) No surface impoundment that has been removed from service in accordance with Section 9(D)(3) of this Chapter may be restored to service unless:
(a) Repairs have been made; and

(b) Repairs have been certified by a qualified Maine licensed professional engineer to ensure that the failure will not recur.

(6) A surface impoundment which has been removed from service and which is not being repaired must be closed in accordance with the closure and post-closure requirements of this Chapter.

E. Inspection, Surveying and Recordkeeping. The facility must comply with the provisions of 40 C.F.R. §264.226, except that the reference to 40 C.F.R. §264.221(a) is deleted. Furthermore, the following requirements apply:

(1) The owner or operator of a surface impoundment must inspect:
(a) The freeboard level at least daily to ensure that two feet of freeboard is being maintained; and

(b) The surface impoundment area, including dikes and vegetation thereon, at least weekly to check for any leaks or discharges and for signs of erosion, deterioration or failure of the impoundment.

(2) Where insufficient freeboard is noted, remedial action must be taken at once.

(3) The owner or operator must maintain, and keep current for as long as the facility is operated, a record of all hazardous waste handled in the impoundment by type, volume and date, all methods and times of treatment, all inspections and all records of repair, accidents and abatement measures taken. The record must be kept at the facility during its operating life and upon closure must be delivered to the Department. The Department may require that a current copy of that record be kept on file with the Department.

F. Air, Ground Water and Surface Water Monitoring

(1) Emissions, including fugitive emissions, from the facility must be monitored in accordance with Section 8(F) of this Chapter.

(2) Ground water must be monitored in accordance with Section 8(D) of this Chapter.

(3) The Board or Department may require surface waters within or adjacent to a facility or facility property to be monitored in accordance with a plan approved by the Board or Department, as applicable.

G. Closure and Post-Closure

(1) The owner or operator of a surface impoundment that does not meet the liner requirements of Section 9(B) of this Chapter shall:
(a) Include in the closure plan for the surface impoundment both a plan for complying with Section 9(G)(2) of this Chapter and a contingency plan for complying with Section 9(G)(3) of this Chapter in case not all contaminated subsoils can be practicably removed at closure;

(b) Prepare a contingency post-closure plan for complying with Section 9(G)(3) of this Chapter in case not all contaminated subsoils can be practicably removed at closure; and

(c) Base the cost estimates for closure and post-closure care required under Section 6(C)(16) of this Chapter on the cost of complying with the more expensive of the two closure and post-closure scenarios.

(2) The owner or operator must remove or decontaminate all waste residues, contaminated containment system components (liners, etc.), contaminated subsoils, and structures and equipment contaminated with waste and leachate, and manage them as hazardous waste unless 06-096 C.M.R. ch. 850, § 3(A)(3)(d) applies; or

(3) If, after removing or decontaminating all residues and making all reasonable efforts to effect removal or decontamination of contaminated components, subsoils, structures and equipment as required in Section 9(G)(2) of this Chapter, the owner or operator finds that not all contaminated subsoils can be practicably removed or decontaminated, the facility must be closed in accordance with the closure and post-closure requirements that apply to landfills in Section 8(H) of this Chapter and with the requirements of 40 C.F.R. §264.228(b).

(4) After closure, hazardous waste surface impoundments must continue to meet the performance standards.

(5) The Department may grant a variance to Section 9(G)(2) of this Chapter if the owner or operator demonstrates that the hazardous constituents in the waste will not migrate into ground water, surface water and air in violation of the performance standards in this Chapter for as long as the waste and other materials will remain on-site. Facilities receiving a variance to Section 9(G)(2) of this Chapter shall close the facility in accordance with the closure and post-closure requirements that apply to landfills.

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