Sec. 26.13.05.12. Waste Piles

A. Applicability.

(1) This regulation applies to owners and operators of facilities that store or treat hazardous waste in piles, except as Regulation .01 of this chapter provides otherwise.

(2) The owner or operator of any waste pile that is inside or under a structure that provides protection from precipitation so that neither run-off nor leachate is generated is not subject to regulation under §§B and D of this regulation and Regulations .06-.06-7 of this chapter, if:

(a) Liquids or materials containing free liquids are not placed in the pile;

(b) The pile is protected from surface water run-on by the structure or in some other manner;

(c) The pile is designed and operated to control dispersal of the waste by wind, when necessary, by means other than wetting; and

(d) The pile does not generate leachate through decomposition or other reactions.

B. Design and Operating Requirements.

(1) A waste pile except for an existing portion of a waste pile, shall have:

(a) A liner that is designed, constructed, and installed to prevent any migration of wastes out of the pile into the adjacent subsurface soil or ground water or surface water at any time during the active life (including the closure period) of the waste pile. The liner may be constructed of materials that may allow waste to migrate into the liner itself (but not into the adjacent subsurface soil or ground water or surface water) during the active life of the facility. The liner shall be:

(i) Constructed of materials that have appropriate chemical properties and sufficient strength and thickness to prevent failure due to pressure gradients (including static head and external hydrogeologic forces), physical contact with the waste or leachate to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation;

(ii) Placed upon a foundation or base capable of providing support to the liner and resistance to pressure gradients above and below the liner to prevent failure of the liner due to settlement, compression, or uplift; and

(iii) Installed to cover all surrounding earth likely to be in contact with the waste or leachate.

(b) A leachate collection and removal system immediately above the liner that is designed, constructed, maintained, and operated to collect and remove leachate from the pile. The Secretary will specify design and operating conditions in the permit to ensure that the leachate depth over the liner does not exceed 30 cm (1 foot). The leachate collection and removal system shall be:

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

(ii) Designed and operated to function without clogging through the scheduled closure of the waste pile.

(c) A containment system which complies with §D of this regulation.

(2) The owner or operator will be exempted from the requirements of §B(1) if the Secretary finds, based on a demonstration by the owner or operator, that alternate design and operating practices together with location characteristics, will prevent the migration of any hazardous constituents (see Regulation .06-1B of this chapter) into the ground water or surface water at any future time. In deciding whether to grant an exemption, the Secretary shall consider:

(a) The nature and quantity of the wastes;

(b) The proposed alternate design and operation;

(c) The hydrogeologic setting of the facility, including attenuative capacity and thickness of the liners and soils present between the pile and ground water or surface water; and

(d) All other factors which would influence the quality and mobility of the leachate produced and the potential for it to migrate to ground water or surface water.

(3) The owner or operator shall design, construct, operate, and maintain a run-on control system capable of preventing flow onto the active portion of the pile during peak discharge from at least a 25-year storm.

(4) The owner or operator shall design, construct, operate, and maintain a run-off management system to collect and control at least the water volume resulting from a 24-hour, 25-year storm.

(5) Collection and holding facilities (for example, tanks or basins) associated with run-on and run-off control systems shall be emptied or otherwise managed expeditiously after storms to maintain design capacity of the system.

(6) If the pile contains any particulate matter which may be subject to wind dispersal, the owner or operator shall cover or otherwise manage the pile to control wind dispersal.

(7) The Secretary will specify in the permit all design and operating practices that are necessary to ensure that the requirements of this section are satisfied.

C. Waste Analysis. In addition to the waste analysis required by Regulation .02D, of this chapter, the owner or operator shall analyze a representative sample of waste from each incoming movement before adding the waste to any existing pile, unless the only wastes the facility receives which are amenable to piling are compatible with each other, or the waste received is compatible with the waste in the pile to which it is to be added. This analysis conducted shall be capable of differentiating between the types of hazardous waste the owner or operator places in piles, so that mixing of incompatible waste does not inadvertently occur. The analysis shall include a visual comparison of color and texture.

D. Containment Systems.

(1) A containment system shall be designed, constructed, maintained, and operated to prevent discharge into the land, surface water, or ground water during the life of the waste pile. This includes the following:

(a) The system shall consist of a leachate and run-off collection and control system, and either:

(i) A base underlying and in contact with the waste pile that is made of a liner or liners which will prevent discharge into the land, surface water, or ground water during the life of the pile based on the liner or liners' thickness, the permeability of the liner or liners and the characteristics of the waste or leachate to which the liner or liners will be exposed. The liner or liners shall be of sufficient strength and thickness to prevent failure due to puncture, cracking, tearing, or other physical damage from equipment used to place waste in or on the pile, or to clean and expose the liner surface for inspection.

(ii) A base as in §D(1)(a)(i), of this regulation, except that the liner or liners need not be of sufficient strength and thickness to prevent failure due to physical damage from equipment used to clean and expose the liner surface for inspection, and a leachate detection, collection, and removal system beneath the base to detect, contain, collect, and remove any discharge from the base. The leachate detection, collection, and removal system shall be placed above the water table to ensure the detection of any discharge through the base, to prevent any discharge of ground water into the leachate detection, collection, and removal system, and to protect the structural integrity of the base.

(b) A highly impermeable liner beneath the drainage layer is a necessary part of the leachate detection, collection, and removal system. The ground water table may be controlled to comply with this requirement.

(2) A waste pile base shall be constructed:

(a) Of materials that have appropriate chemical properties and strength and of sufficient thickness to prevent failure due to pressure of and physical contact with the waste to which they are exposed, climatic conditions, and the stress of installation; and

(b) On a foundation capable of providing support to the liner or liners and to loads placed or moving above the liner or liners to prevent failure of the liner or liners due to settlement or compression.

(3) A containment system shall be protected from plant growth which could puncture any component of the system.

(4) A containment system shall have a containment life equal to or greater than the life of the pile.

E. Inspections and Testing.

(1) During construction or installation of the waste pile base, except in the case of an existing portion of a waste pile exempt from the requirements of §B(1), and immediately after installation:

(a) Liner systems and covers shall be inspected for uniformity, damage, and imperfections (for example, holes, cracks, thin spots, and foreign materials);

(b) Manufactured liner materials and covers (for example, membranes, sheets, and coatings) shall be inspected to ensure tight seams and joints and the absence of tears or blisters; and

(c) Soil-based and admixed liners and covers shall be inspected for imperfections including lenses, cracks, channels, root holes, or other structural non-uniformities that may cause an increase in the permeability of the liner or cover.

(2) Except as otherwise provided in §E(3), of this regulation, the owner or operator of a waste pile shall include in the inspection plan required under Regulation .02 of this chapter. A schedule of inspection of the devices controlling wind dispersal (if required) and run-on, and the waste pile containment system under §D of this regulation. The inspection schedule shall include periodic removal of the waste pile and testing of the underlying base to ensure that it has not deteriorated to the point where it is no longer capable of containment, is already leaking, or is otherwise in disrepair.

(3) If it is impractical to remove the waste pile and test the underlying base periodically because of the size of the pile or the type of base used (for example, a synthetic membrane which could be damaged during waste removal), the owner or operator may omit the pile base inspection from his inspection plan, provided that the pile has a leachate detection, collection, and removal system as specified in §D(1)(a)(ii) of this regulation.

(4) While a waste pile is in operation, it shall be inspected weekly and after storms to detect evidence of any of the following:

(a) Deterioration, malfunctions, or improper operation of run-on and run-off control systems;

(b) The presence of liquids in leak detection systems, if installed;

(c) Proper functioning of wind dispersal control systems, if present; and

(d) The presence of leachate in and proper functioning of leachate collection and removal systems, if present.

F. Containment System Repairs, Contingency Plans.

(1) Whenever there is an indication of a possible failure of the containment system, the system shall be inspected in accordance with the provisions of the containment system evaluation and repair plan required by §F(4) of this regulation. Indications of possible failure of the containment system include liquid detected in the leachate detection system (when applicable), evidence of leakage or the potential for leakage in the base, erosion of the base, or apparent or potential deterioration of the liner and liners based on observation or test samples of the liner materials.

(2) Whenever there is a positive indication of a failure of the containment system, the waste pile shall be removed from service. Indications of positive failure of containment system include waste detected in the leachate detection system (when applicable), or a breach (for example, a hole, tear, crack, or separation) in the base.

(3) If the waste pile must be removed from service as required by §F(2), of this regulation, the owner or operator shall:

(a) Immediately stop adding wastes to the pile;

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

(c) Immediately cause the leak to be stopped; and

(d) If the leak cannot be stopped by another means, remove the waste from the base.

(4) As a part of the contingency plan required in Regulation .04, of this chapter, the owner or operator shall specify:

(a) A procedure for complying with the requirements of §F(3) of this regulation; and

(b) A containment system evaluation and repair plan describing:

(i) Testing and monitoring techniques;

(ii) Procedures to be followed to evaluate the integrity of the containment system in the event of a possible failure;

(iii) A schedule of actions to be taken in the event of a possible failure; and

(iv) A description of the repair techniques to be used in the event of leakage due to containment system failure or deterioration which does not require the waste pile to be removed from service.

(5) A waste pile that has been removed from service in accordance with §F(2), of this regulation, may not be restored to service unless the containment system has been:

(a) Repaired; and

(b) Certified by a qualified engineer as meeting the design specifications approved in the permit.

(6) A waste pile that has been removed from service in accordance with §F(2), of this regulation, and that is not being repaired shall be closed in accordance with §I, of this regulation.

G. Special Requirements for Ignitable or Reactive Waste. Ignitable or reactive waste may not be placed in a pile unless:

(1) The waste is treated, rendered, or mixed before or immediately after placement in the pile so that:

(a) The resulting waste, mixture, or dissolution of materials no longer meets the definition of ignitable or reactive waste under COMAR 26.13.02.11 and .13, and

(b) Regulation .02H of this chapter is complied with; or

(2) The waste is managed in such a way that it is protected from any material or conditions which may cause it to ignite or react.

H. Special Requirements for Incompatible Wastes.

(1) Incompatible wastes, or incompatible wastes and materials, (see Regulation .24, of this chapter, for examples) may not be placed in the same pile, unless Regulation .02H(2) is complied with.

(2) A pile of hazardous waste that is incompatible with any waste or other material stored nearby in other containers, piles, open tanks, or surface impoundments shall be separated from the other materials, or protected from them by means of a dike, berm, wall, or other device.

(3) Hazardous waste may not be piled on the same area where incompatible wastes or materials were previously piled, unless the area has been decontaminated sufficiently to ensure compliance with Regulation .02H(2) of this chapter.

I. Closure and Post-Closure Care.

(1) At closure, the owner or operator shall 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 COMAR 26.13.02.03D applies.

(2) 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 §I(1), of this regulation, the owner or operator finds that not all contaminated subsoils can be practicably removed or decontaminated, he shall close the facility and perform post-closure care in accordance with the closure and post-closure care requirements that apply to landfills.

(3) The owner or operator of a waste pile that does not comply with the liner requirements of §B(1)(a), of this regulation, and is not exempt from them in accordance with §A(2) or B(2), of this regulation, shall:

(a) Include in the closure plan for the pile under Regulation .07C, of this chapter, both a plan for complying with §I(1), of this regulation, and a contingency plan for complying with §I(2), of this regulation, if not all contaminated subsoils can be practicably removed at closure; and

(b) Prepare a contingency post-closure plan under Regulation .07H, of this chapter, for complying with §I(2), of this regulation, if not all contaminated subsoils can be practicably removed at closure.

(4) The cost estimates calculated under Regulation .08 for closure and post-closure care of a pile subject to §I(3), of this regulation, shall include the cost of complying with the contingent closure plan and the contingency post-closure plan, but are not required to include the cost of expected closure under §I(1), of this regulation.

J. Special Requirements for Hazardous Wastes F020, F021, F022, F023, F026, and F027.

(1) Hazardous Waste F020, F021, F022, F023, F026, and F027 may not be placed in waste piles that are not enclosed as defined in §A(2), of this regulation, unless the owner or operator operates the waste pile in accordance with a management plan for these wastes that is approved by the Secretary under the standards set out in this section, and in accord with all other applicable requirements of this chapter. The factors to be considered are:

(a) The volume, physical, and chemical characteristics of the wastes, including their potential to migrate through soil or to volatilize or escape into the atmosphere;

(b) The attenuative properties of underlying and surrounding soils or other materials;

(c) The mobilizing properties of other materials co-disposed with these wastes; and

(d) The effectiveness of additional treatment, design, or monitoring techniques.

(2) The Secretary may determine that additional design, operating, and monitoring requirements are necessary for piles managing hazardous wastes F020, F021, F022, F023, F026, and F027 in order to reduce the possibility of migration of these wastes to ground water, surface water, or air so as to protect human health and the environment.