Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Scope.
This part applies to owners and operators of facilities that
use surface impoundments to treat, store, or dispose of hazardous waste, except
as part
7045.0552 provides
otherwise.
Subp. 1a.
Design and operating requirements.
Design and operating requirements are as follows:
A. The owner or operator of each new surface
impoundment unit on which construction commences after January 29, 1992, each
lateral expansion of a surface impoundment unit on which construction commences
after July 29, 1992, and each replacement of an existing surface impoundment
unit that is to commence reuse after July 29, 1992, must install two or more
liners and a leachate collection and removal system between such liners, and
operate the leachate collection and removal system, in accordance with part
7045.0532, subpart
3, item C, unless exempted
under part
7045.0532, subpart
3, item J or K. "Construction
commences" and "existing facility" are defined in part
7045.0020.
B. The owner or operator of each unit
referred to in item A must notify the commissioner at least 60 days before
receiving waste. The owner or operator of each facility submitting notice must
file a Part B application within six months of the commissioner's receipt of
the notice.
Subp. 2.
General operating requirements.
A. A surface impoundment must maintain enough
freeboard to prevent any overtopping of the dike by overfilling, wave action or
a storm. There must be at least 60 centimeters (two feet) of freeboard. Any
point source discharge from a surface impoundment to waters of the United
States is subject to the requirements of the Federal Water Pollution Control
Act Amendments of 1972, United States Code, title 33, section 1342, as amended.
Spills may be subject to the Federal Water Pollution Control Act Amendments of
1972, United States Code, title 33, section 1312, as amended.
B. Surface impoundments that are newly
subject to RCRA section 3005(j)(1) due to the promulgation of additional
listings or characteristics for the identification of hazardous waste must be
in compliance with subpart
1a not later than 48 months
after the promulgation of the additional listing or characteristic. This
compliance period shall not be cut short as the result of the promulgation of
land disposal prohibitions under Code of Federal Regulations, title 40, part
268, as amended, or the granting of an extension to the effective date of a
prohibition pursuant to Code of Federal Regulations, title 40, section 268.5,
as incorporated in part
7045.1390, within this 48-month
period.
Subp. 2a.
Action leakage rate.
A. The owner
or operator of surface impoundment units subject to subpart
1a, item A, must submit a
proposed action leakage rate to the commissioner when submitting the notice
required under subpart
1a, item B. Within 60 days
of receipt of the notification, the commissioner will establish an action
leakage rate, either as proposed by the owner or operator or modified using the
criteria in this subpart, or extend the review period for up to 30 days. If no
action is taken by the commissioner before the original 60-day or extended
90-day review periods, the action leakage rate will be approved as proposed by
the owner or operator.
B. The
commissioner shall approve an action leakage rate for surface impoundment units
subject to subpart
1a, item A. The action
leakage rate is the maximum design flow rate that the leak detection system can
remove without the fluid head on the bottom liner exceeding one foot. The
action leakage rate must include an adequate safety margin to allow for
uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of
drainage material), construction, operation, and location of the leak detection
system, waste and leachate characteristics, likelihood and amounts of other
sources of liquids in the leak detection system, and proposed response actions
(e.g., the action leakage rate must consider decreases in the flow capacity of
the system over time resulting from siltation and clogging, rib layover and
creep of synthetic components of the system, overburden pressures,
etc.).
C. To determine if the
action leakage rate has been exceeded, the owner or operator must convert the
weekly or monthly flow rate from the monitoring data obtained under subpart
5, item B, to an average
daily flow rate (gallons per acre per day) for each sump. Unless the
commissioner approves a different calculation, the average daily flow rate for
each sump must be calculated weekly during the active life and closure period,
and if the unit closes in accordance with subpart
6, item C, monthly during the
postclosure care period when monthly monitoring is required under subpart
5, item B.
Subp. 2b.
Response
actions.
A. The owner or operator of
surface impoundment units subject to subpart
1a, item A, must submit a
response action plan to the commissioner when submitting the proposed action
leakage rate under subpart
2a. The response action plan
must set forth the actions to be taken if the action leakage rate has been
exceeded. At a minimum, the response action plan must describe the actions
specified in item B.
B. If the flow
rate into the leak detection system exceeds the action leakage rate for any
sump, the owner or operator must:
(1) notify
the commissioner in writing of the exceedence within seven days of the
determination;
(2) submit a
preliminary written assessment to the commissioner within 14 days of the
determination, as to the amount of liquids, likely sources of liquids, possible
location, size, and cause of any leaks, and short-term actions taken and
planned;
(3) determine to the
extent practicable the location, size, and cause of any leak;
(4) determine whether waste receipt should
cease or be curtailed, whether any waste should be removed from the unit for
inspection, repairs, or controls, and whether or not the unit should be
closed;
(5) determine any other
short-term and longer-term actions to be taken to mitigate or stop any leaks;
and
(6) within 30 days after the
notification that the action leakage rate has been exceeded, submit to the
commissioner the results of the analyses specified in subitems (3) to (5), the
results of actions taken, and actions planned. Monthly thereafter, as long as
the flow rate in the leak detection system exceeds the action leakage rate, the
owner or operator must submit to the commissioner a report summarizing the
results of any remedial actions taken and actions planned.
C. To make the leak and/or remediation
determinations in item B, subitems (3) to (5), the owner or operator must:
(1)
(a)
assess the source of liquids and amounts of liquids by source;
(b) conduct a fingerprint, hazardous
constituent, or other analyses of the liquids in the leak detection system to
identify the source of liquids and possible location of any leaks, and the
hazard and mobility of the liquid; and
(c) assess the seriousness of any leaks in
terms of potential for escaping into the environment; or
(2) document why such assessments are not
needed.
Subp.
3.
Containment system.
All 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.
Subp.
4.
Waste analysis and trial tests.
In addition to the waste analyses required by part
7045.0564, whenever a surface
impoundment is to be used to chemically treat a hazardous waste which is
substantially different from waste previously treated in that impoundment or to
chemically treat hazardous waste with a substantially different process than
any previously used in that impoundment, the owner or operator shall, before
treating the different waste or using the different process, conduct waste
analyses and trial treatment tests to show that this treatment will comply with
part
7045.0562, subpart
2. In the alternative, the
owner or operator may obtain written, documented information on similar
treatment of similar waste under similar operating conditions to show that this
treatment will comply with part
7045.0562, subpart
2. As required by part
7045.0564, the waste analysis plan
must include analyses needed to comply with subparts
7 and
8. As required by part
7045.0584, the owner or operator
shall place the results from each waste analysis and trial test, or the
documented information, in the operating record of the facility.
Subp. 5.
Monitoring and
inspection.
A. The owner or operator
shall inspect:
(1) the freeboard level at
least once each operating day to ensure compliance with subpart
2; and
(2) the surface impoundment, including dikes
and vegetation surrounding the dike, at least once a week to detect any leaks,
deterioration, or failures in the impoundment. As required by part
7045.0556, subpart
5, the owner or operator
shall remedy any deterioration or malfunction found.
B. The owner or operator shall determine
leaks as follows:
(1) An owner or operator
required to have a leak detection system under subpart
1a, item A, must record the
amount of liquids removed from each leak detection system sump at least once
each week during the active life and closure period.
(2) After the final cover is installed, the
amount of liquids removed from each leak detection system sump must be recorded
at least monthly. If the liquid level in the sump stays below the pump
operating level for two consecutive months, the amount of liquids in the sumps
must be recorded at least quarterly. If the liquid level in the sump stays
below the pump operating level for two consecutive quarters, the amount of
liquids in the sumps must be recorded at least semiannually. If at any time
during the postclosure care period the pump operating level is exceeded at
units on quarterly or semiannual recording schedules, the owner or operator
must return to monthly recording of amounts of liquids removed from each sump
until the liquid level again stays below the pump operating level for two
consecutive months.
(3) "Pump
operating level" is a liquid level proposed by the owner or operator and
approved by the commissioner based on pump activation level, sump dimensions,
and level that avoids backup into the drainage layer and minimizes head in the
sump. The timing for submission and approval of the proposed pump operating
level will be in accordance with subpart
2a, item A.
Subp. 6.
Closure
and postclosure care.
The requirements of closure and postclosure care are as
follows:
A. At closure, the owner or
operator may elect to remove from the impoundment or decontaminate any standing
liquids, waste and waste residues, contaminated containment system components
including liners, if any, underlying and surrounding contaminated soil, and
structures and equipment contaminated with waste and leachate.
B. If the owner or operator removes or
decontaminates all the impoundment materials described in item A, the
impoundment is not further subject to the requirements of parts
7045.0552 to
7045.0649. At closure and
throughout the operating period, unless the owner or operator can demonstrate
that any waste removed from the surface impoundment is not a hazardous waste,
he or she becomes a generator of hazardous waste and must manage it in
accordance with all applicable requirements of parts
7045.0205 to
7045.0397 and
7045.0552 to
7045.0649.
C. If the owner or operator does not remove
or decontaminate all the impoundment materials described in item A, he or she
shall close the impoundment and provide postclosure care as for a landfill
under parts
7045.0594 to
7045.0606 and
7045.0638, subpart
4, including the following:
(1) eliminate free liquids by removing liquid
wastes or solidifying the remaining wastes and waste residues;
(2) stabilize remaining wastes to a bearing
capacity sufficient to support the final cover; and
(3) cover the surface impoundment with a
final cover designed and constructed to provide long term minimization of the
migration of liquids through the closed impoundment, function with minimum
maintenance, promote drainage and minimize erosion or abrasion of the cover,
accommodate settling and subsidence so that the cover's integrity is
maintained, and have a permeability less than or equal to the permeability of
any bottom liner system or natural subsoils present.
D. In addition to the requirements of parts
7045.0594 to
7045.0606 and
7045.0638, subpart
4, during the postclosure
care period, the owner or operator of a surface impoundment in which wastes,
waste residues, or contaminated materials remain after closure in accordance
with item C shall:
(1) maintain the integrity
and effectiveness of the final cover, including making repairs to the cover as
necessary to correct the effects of settling, subsidence, erosion, or other
events;
(2) maintain and monitor
the leak detection system in accordance with subpart
5, item B, and comply with
all other applicable leak detection system requirements;
(3) maintain and monitor the groundwater
monitoring system and comply with all other applicable requirements of part
7045.0590; and
(4) prevent run-on and runoff from eroding or
otherwise damaging the final cover.
The closure requirements under part
7045.0638, subpart
4, will vary with the amount
and nature of the residues remaining, if any, and the degree of contamination
of the underlying and surrounding soil. The commissioner may vary postclosure
requirements, according to part
7045.0602, subpart
1.
Subp. 7.
Special
requirements for ignitable or reactive wastes.
Ignitable or reactive waste must not be placed in a surface
impoundment unless the waste and the impoundment satisfy all applicable
requirements of part
7045.1390, and:
A. the waste is treated, rendered, or mixed
before or immediately after placement in the impoundment so that the resulting
waste, mixture, or dissolution of material no longer meets the definition of
ignitable or reactive waste under parts
7045.0131, subpart
2 or
5; and 7045.0562, subpart
2 is followed; or
B. the surface impoundment is used solely for
emergencies.
Subp. 8.
Special requirements for incompatible wastes.
Incompatible waste, or incompatible wastes and materials,
must not be placed in the same surface impoundment unless part
7045.0562, subpart
2, is followed. For examples
of potentially incompatible wastes, or incompatible waste and materials, see
part
7045.0643, subpart
1,
item D.
Subp. 9.
Air
emission standards.
The owner or operator must manage all hazardous waste placed
in a surface impoundment in accordance with parts
7045.0645 and
7045.0648.
Statutory Authority: MS s
116.07;
116.37
