Current through August 26, 2024
(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.
