Sec. 26.13.05.17-2. Design and Operating Requirements

A. The owner or operator of a drip pad shall ensure that:

(1) The drip pad:

(a) Is constructed of non-earthen materials, excluding wood and non-structurally supported asphalt;

(b) Is sloped to efficiently drain treated wood drippage, rain and other waters, or solutions of drippage and water or other wastes to the associated collection system; and

(c) Has a curb or berm around the perimeter;

(2) For an existing drip pad which does not satisfy the requirements of §C of this regulation, and for a new drip pad for which the owner or operator has elected to comply with this provision, as provided in Regulation .17-1C(2)(a) of this chapter, the surface material of the drip pad:

(a) Has a hydraulic conductivity of less than or equal to 1X10-7 centimeters per second by, for example, sealing, coating, or covering a concrete drip pad with a surface material with a hydraulic conductivity of less than or equal to 1X10-7 centimeters per second, so that the entire surface where drippage occurs or may run across is capable of containing the drippage and mixtures of drippage and precipitation, materials, or other wastes while being routed to an associated collection system;

(b) Is maintained free of cracks and gaps that could adversely affect its ability to contain liquids; and

(c) Is chemically compatible with the preservatives that contact the drip pad; and

(3) The drip pad is of sufficient structural strength and thickness to prevent failure due to:

(a) Physical contact;

(b) Climatic conditions;

(c) Stresses associated with daily operations such as vehicular traffic and movement of wood;

(d) The stress of installation; and

(e) Any other relevant factors.

B. Written Assessment. If, as provided in Regulation .17-1C(2)(a) of this chapter, the owner or operator elects to comply with the requirements of §A(2) of this regulation, the owner or operator shall also:

(1) Obtain and keep on file at the facility a written assessment of the drip pad that evaluates the extent to which the drip pad meets the design and operating standards of this regulation, except for the requirements of §C of this regulation; and

(2) Have the assessment required by §B(1) of this regulation:

(a) Reviewed and certified by an independent, qualified registered professional engineer that attests to the results of the evaluation; and

(b) Updated, reviewed, and recertified annually.

C. The owner or operator of a drip pad who has chosen to install a liner and leakage detection and collection system, as provided in Regulation .17-1C(2)(b) of this chapter or Regulation .17-1D(1) of this chapter, shall ensure that the system complies with the following:

(1) A synthetic liner, which is designed, constructed, and installed to prevent leakage from the drip pad into surface water, ground water, or adjacent subsurface soil at any time during the active life and closure period of the drip pad, is installed below the drip pad;

(2) The liner required by §C(1) of this regulation is constructed of materials that will prevent waste from being absorbed into the liner and that will prevent releases into surface water, ground water, or adjacent subsurface soil during the active life of the facility;

(3) The liner required by §C(1) of this regulation is:

(a) Constructed of materials that have appropriate chemical properties and sufficient strength and thickness to prevent failure due to:

(i) Pressure gradients such as static head and external hydrogeologic forces;

(ii) Physical contact with the waste or with drip pad leakage;

(iii) Climatic conditions;

(iv) The stress of installation; and

(v) The stress of daily operation, including stresses from vehicular traffic on the drip pad;

(b) Placed upon a foundation or base capable of:

(i) Providing support to the liner;

(ii) Providing resistance to pressure gradients above and below the liner; and

(iii) Preventing failure of the liner due to settlement, compression, or uplift; and

(c) Installed to cover all surrounding earth that could come in contact with the waste or leakage;

(4) There is a leakage detection system immediately above the liner that is designed, constructed, maintained, and operated to detect leakage from the drip pad;

(5) The leakage detection system required by §C(4) of this regulation is:

(a) Constructed of materials that are:

(i) Chemically resistant to the waste managed in the drip pad and the leakage that might be generated; and

(ii) Of sufficient strength and thickness to prevent collapse under the pressures exerted by overlaying materials and by any equipment used at the drip pad;

(b) Designed and operated to function without clogging through the scheduled closure of the drip pad; and

(c) Designed to detect the failure of the drip pad or the presence of a release of hazardous waste or accumulated liquid at the earliest practicable time;

(6) There is a leakage collection system immediately above the liner that is designed, constructed, maintained, and operated to collect leakage from the drip pad so that it can be removed from below the drip pad; and

(7) The date, time, and quantity of any leakage collected in and removed from the leakage collection system is documented in the facility operating log.

D. General Design and Operating Requirements. The owner or operator of a drip pad shall:

(1) Maintain the drip pad so that it remains free of cracks, gaps, corrosion, or other deterioration that could cause hazardous waste to be released from the drip pad;

(2) Ensure that the drip pad and associated collection system are designed and operated to convey, drain, and collect liquid resulting from drippage or precipitation in order to prevent run-off;

(3) Unless the drip pad is protected by a structure, as described in Regulation .17-1A(4) of this chapter:

(a) Either:

(i) Design, construct, operate, and maintain a run-on control system capable of preventing flow onto the drip pad during peak discharge from at least a 24-hour, 25-year storm; or

(ii) Assure that the run-on control system has sufficient excess capacity to contain any surface water run-off that might enter the system; and

(b) 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;

(4) Remove drippage and accumulated precipitation from the associated collection system as necessary to prevent overflow onto the drip pad;

(5) Ensure that collection and holding units associated with run-on and run-off control systems are emptied or otherwise managed as soon as possible after storms to maintain the design capacity of the system; and

(6) Operate and maintain drip pads in a manner that minimizes tracking of hazardous waste or hazardous waste constituents off the drip pad as a result of activities by personnel or equipment.

E. The owner or operator shall:

(1) Evaluate the drip pad to determine whether it meets the requirements of §§A-D(3) of this regulation; and

(2) Obtain a statement from an independent qualified registered professional engineer certifying that the drip pad design meets the requirements of this regulation.

F. Cleaning Requirements.

(1) The owner or operator of a drip pad shall:

(a) Thoroughly clean the drip pad surface to remove accumulated residues of hazardous waste or other materials to allow weekly inspections of the entire drip pad surface without interference or hindrance from materials on the drip pad;

(b) Document, in the facility's operating record, the date, time, and cleaning procedure used for each cleaning required by §F(1)(a) of this regulation; and

(c) Determine if the residues resulting from each cleaning required in §F(1)(a) of this regulation are regulated as hazardous under COMAR 26.13.02 and, if so, manage them in accordance with COMAR 26.13.02-26.13.10, §3010 of RCRA, and applicable federal regulations.

(2) In satisfying the cleaning requirement of §F(1) of this regulation, the owner or operator may clean the drip pad less frequently than once every 7 days, if doing so does not prevent unobscured viewing the drip pad surface during inspection.

G. After treated wood from pressure and nonpressure processes has been removed from the treatment vessel, the owner or operator shall ensure that it is held on the drip pad until drippage has ceased.

H. The owner or operator of a drip pad shall maintain records sufficient to document that all treated wood is held on the pad following treatment in accordance with §G of this regulation.

I. Response to Releases and Potential Releases.

(1) Throughout the active life of the drip pad, and as specified in the facility's permit, upon detection of a release of hazardous waste, including discovery of leakage in the leak detection system, or upon detection of a condition that may have caused or has caused a release, the owner or operator shall:

(a) Enter a record of the discovery in the facility operating log;

(b) Immediately remove from service the affected portion of the drip pad;

(c) Determine the steps that shall be taken to repair the drip pad and clean up any leakage from below the drip pad, and establish a schedule for accomplishing the repairs;

(d) Within 24 hours after discovery of the release or the condition that may have caused the release, notify the Secretary of the situation; and

(e) Within 10 working days after discovery of the release or the condition that may have caused the release, provide written notice to the Secretary with a plan describing the steps that will be taken to repair the drip pad and clean up any leakage, and a schedule for accomplishing this work.

(2) The Secretary shall:

(a) Review the information submitted;

(b) Make a determination regarding whether the pad is to be removed from service completely or partially until repairs and clean up are complete; and

(c) Notify the owner or operator of the determination and the underlying rationale in writing.

(3) Upon completing all the repairs and implementing the clean up specified in the plan submitted in accordance with §I(1)(e) of this regulation, the owner or operator shall notify the Secretary in writing and provide a certification signed by an independent qualified registered professional engineer that the repairs and clean up have been completed according to the written plan.

J. The owner or operator shall maintain, as part of the facility operating log, documentation of past operating and waste handling practices, including:

(1) Identification of preservative formulations used in the past;

(2) A description of drippage management practices; and

(3) A description of treated wood storage and handling practices.