Section NR 665.0443 - Design and operating requirements(1) Drip pads shall comply with all of the following:(a) Be constructed of non-earthen materials, excluding wood and non-structurally supported asphalt.(b) Be sloped to free-drain treated wood drippage, rain and other waters, or solutions of drippage and water or other wastes to the associated collection system.(c) Have a curb or berm around the perimeter.(d)1. Have a hydraulic conductivity of less than or equal to 1×10-7 centimeters per second, e.g., existing concrete drip pads shall be sealed, coated or covered with a surface material with a hydraulic conductivity of less than or equal to 1×10 -7 centimeters per second such 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. This surface material shall be maintained free of cracks and gaps that could adversely affect its hydraulic conductivity, and the material shall be chemically compatible with the preservatives that contact the drip pad. The requirements of this provision apply only to existing drip pads and those drip pads for which the owner or operator elects to comply with s. NR 665.0442(2) instead of s. NR 665.0442(1).2. The owner or operator shall obtain and keep on file at the facility a written assessment of the drip pad, reviewed and certified by an independent, qualified registered professional engineer that attests to the results of the evaluation. The assessment shall be reviewed, updated and recertified annually. The evaluation shall document the extent to which the drip pad meets the design and operating standards of this section, except for sub. (2).(e) Be of sufficient structural strength and thickness to prevent failure due to physical contact, climatic conditions, the stress of installation and the stress of daily operations, including variable and moving loads such as vehicle traffic or movement of wood. Note: The department will generally consider applicable standards established by professional organizations generally recognized by industry such as the American Concrete Institute (ACI) and the American Society of Testing Materials (ASTM) in judging the structural integrity requirement of par. (e).
(2) If an owner or operator elects to comply with s. NR 665.0442(1) instead of s. NR 665.0442(2), the drip pad shall have all of the following: (a) A synthetic liner installed below the drip pad that is designed, constructed and installed to prevent leakage from the drip pad into the adjacent subsurface soil or groundwater or surface water at any time during the active life (including the closure period) of the drip pad. The liner shall be constructed of materials that will prevent waste from being absorbed into the liner and prevent releases into the adjacent subsurface soil or groundwater or surface water during the active life of the facility. The liner shall comply with all of the following: 1. Be 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 drip pad leakage to which they are exposed, climatic conditions, the stress of installation and the stress of daily operation (including stresses from vehicular traffic on the drip pad).2. Be 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.3. Be installed to cover all surrounding earth that could come in contact with the waste or leakage.(b) A leakage detection system immediately above the liner that is designed, constructed, maintained and operated to detect leakage from the drip pad. The leakage detection system shall comply with all of the following:1. Be constructed of materials that are all of the following: a. Chemically resistant to the waste managed in the drip pad and the leakage that might be generated.b. Of sufficient strength and thickness to prevent collapse under the pressures exerted by overlaying materials and by any equipment used at the drip pad.2. Be designed and operated to function without clogging through the scheduled closure of the drip pad.3. Be designed so that it will detect the failure of the drip pad or the presence of a release of hazardous waste or accumulated liquid at the earliest practicable time.(c) A leakage collection system immediately above the liner that is designed, constructed, maintained and operated to collect leakage from the drip pad such that it can be removed from below the drip pad. The date, time and quantity of any leakage collected in this system and removed shall be documented in the operating log.(3) Drip pads shall be maintained such that they remain free of cracks, gaps, corrosion or other deterioration that could cause hazardous waste to be released from the drip pad. Note: See sub. (13) for remedial action required if deterioration or leakage is detected.
(4) The drip pad and associated collection system shall be designed and operated to convey, drain and collect liquid resulting from drippage or precipitation in order to prevent run-off.(5) Unless protected by a structure, as described in s. NR 665.0440(2), the owner or operator shall 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 unless the system has sufficient excess capacity to contain any run-on that might enter the system, or the drip pad is protected by a structure or cover, as described in s. NR 665.0440(2).(6) Unless protected by a structure or cover, as described in s. NR 665.0440(2), 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.(7) The drip pad shall be evaluated to determine that it meets the requirements of subs. (1) to (6), and the owner or operator shall obtain a statement from an independent, qualified registered professional engineer certifying that the drip pad design meets the requirements of this section. (8) Drippage and accumulated precipitation shall be removed from the associated collection system as necessary to prevent overflow onto the drip pad.(9) The drip pad surface shall be cleaned thoroughly in a manner and frequency such that accumulated residues of hazardous waste or other materials are removed, with residues being properly managed as hazardous waste, so as to allow weekly inspections of the entire drip pad surface without interference or hindrance from accumulated residues of hazardous waste or other materials on the drip pad. The owner or operator shall document the date and time of each cleaning and the cleaning procedure used in the facility's operating log.(10) Drip pads shall be operated and maintained in a manner to minimize tracking of hazardous waste or hazardous waste constituents off the drip pad as a result of activities by personnel or equipment.(11) After being removed from the treatment vessel, treated wood from pressure and non-pressure processes shall be held on the drip pad until drippage has ceased. The owner or operator shall maintain records sufficient to document that all treated wood is held on the pad following treatment in accordance with this requirement.(12) Collection and holding units associated with run-on and run-off control systems shall be emptied or otherwise managed as soon as possible after storms to maintain design capacity of the system.(13) Throughout the active life of the drip pad, if the owner or operator detects a condition that may have caused or has caused a release of hazardous waste, the condition shall be repaired within a reasonably prompt period of time following discovery, in accordance with all of the following procedures: (a) Upon detection of a condition that may have caused or has caused a release of hazardous waste (e.g., upon detection of leakage by the leak detection system), the owner or operator shall do all of the following:1. Enter a record of the discovery in the facility operating log.2. Immediately remove the portion of the drip pad affected by the condition from service.3. Determine what steps must be taken to repair the drip pad and remove any leakage from below the drip pad, and establish a schedule for accomplishing the clean up and repairs.4. Immediately after discovery of the condition, notify the department of the condition and, within 10 working days, provide a written notice to the department with a description of the steps that will be taken to repair the drip pad and clean up any leakage, and the schedule for accomplishing this work.(b) The department will review the information submitted, make a determination regarding whether the pad must be removed from service completely or partially until repairs and clean up are complete, and notify the owner or operator of the determination and the underlying rationale in writing.(c) Upon completing all repairs and clean up, the owner or operator shall notify the department 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 submitted in accordance with par. (a) 4. (14) The owner or operator shall maintain, as part of the facility operating log, documentation of past operating and waste handling practices. This shall include identification of preservative formulations used in the past, a description of drippage management practices and a description of treated wood storage and handling practices.Wis. Admin. Code Department of Natural Resources NR 665.0443
CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06.