Current through Register Vol. 24-06, March 15, 2024
(1)
Applicability. The regulations in this section apply to owners and operators of
facilities that use surface impoundments to treat, store, or dispose of
dangerous waste.
(2) Design and
operating requirements.
(a)
(i) Any surface impoundment that is not
covered by (j) of this subsection must have a liner for all portions of the
impoundment (except for an existing portion of a surface impoundment). The
liner must be designed, constructed, and installed to prevent any migration of
wastes out of the impoundment to the adjacent subsurface soil or groundwater or
surface water at any time during the active life (including the closure period)
of the impoundment. The liner may be constructed of materials that may allow
wastes to migrate into the liner (but not into the adjacent subsurface soil or
groundwater or surface water) during the active life of the facility, provided
that the impoundment is closed in accordance with subsection (6)(a)(i) of this
section. For impoundments that will be closed in accordance with subsection
(6)(a)(ii) of this section, the liner must be constructed of materials that can
prevent wastes from migrating into the liner during the active life of the
facility. The liner must be:
(A) 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;
(B) 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;
(C)
Installed to cover all surrounding earth likely to be in contact with the waste
or leachate; and
(D) For EHW
management, the owner or operator must submit an engineering report with their
permit application under WAC
173-303-806(4)
stating the basis for selecting the liner(s). The report must be certified by
an independent, qualified registered professional engineer.
(ii) The owner or operator of a new surface
impoundment installed after October 31, 1984, and in which liquid EHW is
managed must:
(A) Install a double lined
system which incorporates the specifications of subsection (3)(a), (b), and (c)
of this section; and
(B) Must
comply with either the groundwater monitoring requirements of WAC
173-303-645,
or the unsaturated zone monitoring requirements of WAC
173-303-655(6).
(b) The owner or operator will be exempted
from the requirements of (a) of this subsection, if the department 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 dangerous constituents listed in WAC
173-303-9905,
or which otherwise cause his wastes to be regulated under this chapter, into
the groundwater or surface water at any future time. In deciding whether to
grant an exemption, the department will consider:
(i) The nature and quantity of the
wastes;
(ii) The proposed alternate
design and operation;
(iii) The
hydrogeologic setting of the facility, including the attenuative capacity and
thickness of the liners and soils present between the impoundment and
groundwater or surface water; and
(iv) All other factors which would influence
the quality and mobility of the leachate produced and the potential for it to
migrate to groundwater or surface water.
(c) A surface impoundment must be designed,
constructed, maintained, and operated to prevent overtopping resulting from
normal or abnormal operations; overfilling; wind and wave action; rainfall;
run-on; malfunctions of level controllers, alarms, and other equipment; and
human error.
(d) A surface
impoundment must be designed so that any flow of waste into the impoundment can
be immediately shut off in the event of overtopping or liner failure.
(e) A surface impoundment must be designed to
repel birds.
(f) A surface
impoundment must have dikes that are designed, constructed, and maintained with
sufficient structural integrity to prevent their failure. In ensuring
structural integrity, it must not be presumed that the liner system will
function without leakage during the active life of the unit.
(g) Earthen dikes must be kept free of:
(i) Perennial woody plants with root systems
which could weaken its structural integrity; and
(ii) Burrowing mammals which could weaken its
structural integrity or create leaks through burrows.
(h) 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.
(i) The department will specify in the permit
all design and operating practices that are necessary to ensure that the
requirements of this subsection are satisfied.
(j) 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.
"Construction commences" is as defined in WAC
173-303-040 under
"existing TSD facility."
(i) The liner system
must include:
(A) A top liner designed and
constructed of materials (e.g., a geomembrane) to prevent the migration of
dangerous constituents into such liner during the active life and post-closure
care period; and
(B) A composite
bottom liner, consisting of at least two components. The upper component must
be designed and constructed of materials (e.g., a geomembrane) to prevent the
migration of dangerous constituents into this component during the active life
and post-closure care period. The lower component must be designed and
constructed of materials to minimize the migration of dangerous constituents if
a breach in the upper component were to occur. The lower component must be
constructed of at least 3 feet (91 cm) of compacted soil material with a
hydraulic conductivity of no more than 1 x 10-7
cm/sec.
(ii) The liners
must comply with (a)(i)(A), (B), and (C) of this subsection.
(iii) The leachate collection and removal
system between the liners, and immediately above the bottom composite liner in
the case of multiple leachate collection and removal systems, is also a leak
detection system. This leak detection system must be capable of detecting,
collecting, and removing leaks of dangerous constituents at the earliest
practicable time through all areas of the top liner likely to be exposed to
waste or leachate during the active life and post-closure care period. The
requirements for a leak detection system in this paragraph are satisfied by
installation of a system that is, at a minimum:
(A) Constructed with a bottom slope of one
percent or more;
(B) Constructed of
granular drainage materials with a hydraulic conductivity of 1 x
10-1 cm/sec or more and a thickness of 12 inches
(30.5 cm) or more; or constructed of synthetic or geonet drainage materials
with a transmissivity of 3 x 10-4
m2/sec or more;
(C) Constructed of materials that are
chemically resistant to the waste managed in the surface impoundment and the
leachate expected to be generated, and of sufficient strength and thickness to
prevent collapse under the pressures exerted by overlying wastes and any waste
cover materials or equipment used at the surface impoundment;
(D) Designed and operated to minimize
clogging during the active life and post-closure care period; and
(E) Constructed with sumps and liquid removal
methods (e.g., pumps) of sufficient size to collect and remove liquids from the
sump and prevent liquids from backing up into the drainage layer. Each unit
must have its own sump(s). The design of each sump and removal system must
provide a method for measuring and recording the volume of liquids present in
the sump and of liquids removed.
(iv) The owner or operator will collect and
remove pumpable liquids in the sumps to minimize the head on the bottom
liner.
(v) The owner or operator of
a leak detection system that is not located completely above the seasonal high
water table must demonstrate that the operation of the leak detection system
will not be adversely affected by the presence of ground-water.
(k) The department may approve
alternative design or operating practices to those specified in (j) of this
subsection if the owner or operator demonstrates to the department that such
design and operating practices, together with location characteristics:
(i) Will prevent the migration of any
dangerous constituent into the groundwater or surface water at least as
effectively as the liners and leachate collection and removal system specified
in (j) of this subsection; and
(ii)
Will allow detection of leaks of dangerous constituents through the top liner
at least as effectively.
(l) The double liner requirement set forth in
(j) of this subsection may be waived by the department for any mono-fill, if:
(i) The monofill contains only dangerous
wastes from foundry furnace emission controls or metal casting molding sand,
and such wastes do not contain constituents which would render the wastes
dangerous for reasons other than the toxicity characteristic in WAC
173-303-090(8)
or the toxicity criteria at WAC
173-303-100(5);
and
(ii)
(A) The monofill has at least one liner for
which there is no evidence that such liner is leaking. For the purposes of this
paragraph, the term "liner" means a liner designed, constructed, installed, and
operated to prevent dangerous waste from passing into the liner at any time
during the active life of the facility, or a liner designed, constructed,
installed, and operated to prevent dangerous waste from migrating beyond the
liner to adjacent subsurface soil, groundwater, or surface water at any time
during the active life of the facility. In the case of any surface impoundment
which has been exempted from the requirements of (j) of this subsection on the
basis of a liner designed, constructed, installed, and operated to prevent
dangerous waste from passing beyond the liner, at the closure of such
impoundment, the owner or operator must remove or decontaminate all waste
residues, all contaminated liner material, and contaminated soil to the extent
practicable. If all contaminated soil is not removed or decontaminated, the
owner or operator of such impoundment will comply with appropriate post-closure
requirements, including but not limited to groundwater monitoring and
corrective action;
(B) The monofill
is located more than one-quarter mile from an underground source of drinking
water (as that term is defined in WAC
173-303-040 );
and
(C) The monofill is in
compliance with generally applicable groundwater monitoring requirements for
facilities with permits under RCRA section 3005(c); or
(iii) The owner or operator demonstrates that
the mono-fill is located, designed and operated so as to assure that there will
be no migration of any dangerous constituent into groundwater or surface water
at any future time.
(m)
The owner or operator of any replacement surface impoundment unit is exempt
from (j) of this subsection if:
(i) The
existing unit was constructed in compliance with the design standards of
sections 3004 (o)(1)(A)(i) and (o)(5) of the Resource Conservation and Recovery
Act; and
(ii) There is no reason to
believe that the liner is not functioning as designed.
(4) Monitoring and inspection.
(a) During construction and installation,
liners (except in the case of existing portions of surface impoundments exempt
from subsection (2)(a)(i) of this section) and cover systems (e.g., membranes,
sheets, or coatings) must be inspected for uniformity, damage, and
imperfections (e.g., holes, cracks, thin spots, or foreign materials).
Immediately after construction or installation:
(i) Synthetic liners and covers must be
inspected to ensure tight seams and joints and the absence of tears, punctures,
or blisters; and
(ii) Soil-based
and admixed liners and covers must be inspected for imperfections including
lenses, cracks, channels, root holes, or other structural nonuniformities that
may cause an increase in the permeability of the liner or cover.
(b) While a surface impoundment is
in operation, it must be inspected weekly and after storms to detect evidence
of any of the following:
(i) Deterioration,
malfunctions, or improper operation of overtopping control systems;
(ii) Sudden drops in the level of the
impoundment's contents; and
(iii)
Severe erosion or other signs of deterioration in dikes or other containment
devices.
(c) Prior to the
issuance of a permit, and after any extended period of time (at least six
months) during which the impoundment was not in service, the owner or operator
must obtain a certification from an independent qualified registered
professional engineer that the impoundment's dike, including that portion of
any dike which provides freeboard, has structural integrity. The certification
must establish, in particular, that the dike:
(i) Will withstand the stress of the pressure
exerted by the types and amounts of wastes to be placed in the impoundment;
and
(ii) Will not fail due to
scouring or piping, without dependence on any liner system included in the
surface impoundment construction.
(d)
(i) An
owner or operator required to have a leak detection system under subsection
(2)(j) or (k) of this section 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.
(ii) 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 semi annually. If at any time during the post-closure 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.
(iii) "Pump operating level" is a liquid
level proposed by the owner or operator and approved by the department based on
pump activation level, sump dimensions, and level that avoids backup into the
drainage layer and minimizes head in the sump.
(5) Emergency repairs; contingency plans.
(a) A surface impoundment must be removed
from service in accordance with (b) of this subsection when:
(i) Unexpected changes of liquid levels
occur; or
(ii) The dike
leaks.
(b) When a surface
impoundment must be removed from service as required by (a) of this subsection,
the owner or operator must:
(i) Immediately
shut off the flow or stop the addition of wastes into the
impoundment;
(ii) Immediately
contain any surface leakage which has occurred or is occurring;
(iii) Immediately stop the leak;
(iv) Take any other necessary steps to stop
or prevent catastrophic failure;
(v) Empty the impoundment, if a leak cannot
be stopped by any other means; and
(vi) Notify the department of the problem in
writing within seven days after detecting the problem.
(c) As part of the contingency plan required
in WAC
173-303-340
through
173-303-360, the
owner or operator must specify:
(i) A
procedure for complying with the requirements of (b) of this subsection;
and
(ii) A containment system
evaluation and repair plan describing: Testing and monitoring techniques;
procedures to be followed to evaluate the integrity of the containment system
in the event of a possible failure; description of a schedule of actions to be
taken in the event of a possible failure; and the repair techniques and
materials (and their availability) to be used in the event of leakage due to
containment system failure or deterioration which does not require the
impoundment to be removed from service.
(d) No surface impoundment that has been
removed from service in accordance with the requirements of this section may be
restored to service unless the portion of the impoundment which was failing is
repaired and the following steps are taken:
(i) If the impoundment was removed from
service as the result of actual or imminent dike failure, the dike's structural
integrity must be recertified in accordance with subsection (4)(c) of this
section;
(ii) If the impoundment
was removed from service as the result of a sudden drop in the liquid level,
then:
(A) For any existing portion of the
impoundment, a liner must be installed in compliance with subsection (2)(a)(i)
or (3) of this section; and
(B) For
any other portion of the impoundment, the repaired liner system must be
certified by an independent qualified registered professional engineer as
meeting the design specifications approved in the permit.
(e) A surface impoundment that has
been removed from service in accordance with the requirements of this section
and that is not being repaired must be closed in accordance with the provisions
of subsection (6) of this section.
(6) Closure and post-closure care.
(a) At closure, the owner or operator must:
(i) Remove or decontaminate all dangerous
waste and dangerous waste residues, contaminated containment system components
(liners, etc.), contaminated subsoils, and structures and equipment
contaminated with dangerous waste and leachate, and manage them as dangerous
waste; or
(ii) If the surface
impoundment will be closed as a landfill, except that this option is prohibited
if EHW would remain in the closed unit(s):
(A) Eliminate free liquids by removing liquid
wastes or solidifying the remaining wastes and waste residues;
(B) Stabilize remaining wastes to a bearing
capacity sufficient to support a final cover; and
(C) Cover the surface impoundment with a
final cover designed and constructed to:
(I)
Provide long-term minimization of the migration of liquids through the closed
impoundment with a material that has a permeability less than or equal to the
permeability of any bottom liner system or natural subsoils present;
(II) Function with minimum
maintenance;
(III) Promote drainage
and minimize erosion or abrasion of the final cover; and
(IV) Accommodate settling and subsidence so
that the cover's integrity is maintained.
(b) If some waste residues or
contaminated materials are left in place at final closure (except that no EHW
may ever be left in place), the owner or operator must comply with all
post-closure requirements contained in WAC
173-303-610(7), (8), (9),
and (10), including maintenance and
monitoring throughout the post-closure care period (specified in the permit).
The owner or operator must:
(i) Maintain the
integrity and effectiveness of the final cover, including making repairs to the
cap as necessary to correct the effects of settling, subsidence, erosion, or
other events;
(ii) Maintain and
monitor the leak detection system in accordance with subsections (2)(j)(iii)(D)
and (E), and (4)(d) of this section, and comply with all other applicable leak
detection system requirements of this chapter;
(iii) Maintain and monitor the groundwater
monitoring system and comply with all applicable requirements of WAC
173-303-645;
and
(iv) Prevent run-on and runoff
from eroding or otherwise damaging the final cover.
(c)
(i) If
an owner or operator plans to close a surface impoundment in accordance with
(a)(i) of this subsection, and the impoundment does not comply with the liner
requirements of subsection (2)(a)(i) of this section, and is not exempt from
them in accordance with subsection (2)(b) of this section, then:
(A) The closure plan for the impoundment
under WAC
173-303-610(3)
must include both a plan for complying with (a)(i) of this subsection, and a
contingent plan for complying with (a)(ii) of this subsection in case not all
contaminated subsoils can be practicably removed at closure; and
(B) The owner or operator must prepare a
contingent post-closure plan under WAC
173-303-610(8)
for complying with (b) of this subsection in case not all contaminated subsoils
can be practicably removed at closure.
(ii) The cost estimates calculated under WAC
173-303-620(3) and
(5) for closure and post-closure care of an
impoundment subject to (c) of this subsection must include the cost of
complying with the contingent closure plan and the contingent post-closure
plan, but are not required to include the cost of expected closure under (a)(i)
of this subsection. Reserve.
(7) Special requirements for ignitable or
reactive waste. Ignitable or reactive waste must not be placed in a surface
impoundment, unless the waste and impoundment satisfy all applicable
requirements of WAC
173-303-140(2)(a),
and:
(a) The waste is treated, rendered, or
mixed before or immediately after placement in the impoundment so that:
(i) The resulting waste, mixture, or
dissolution of material no longer meets the definition of ignitable or reactive
waste under WAC
173-303-090;
and
(ii) WAC
173-303-395(1)(b)
is complied with; or
(b)
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; or
(c) The surface impoundment is used solely
for emergencies.
(8)
Special requirements for incompatible wastes. Incompatible wastes and materials
must not be placed in the same surface impoundment, unless WAC
173-303-395(1)(b)
is complied with.
(9) Special
requirements for dangerous wastes F020, F021, F022, F023, F026, and F027.
(a) The wastes F020, F021, F022, F023, F026,
or F027 must not be placed in a surface impoundment unless the owner or
operator operates the surface impoundment in accordance with a management plan
for these wastes that is approved by the department pursuant to the standards
set out in this subsection, and in accord with all other applicable
requirements of this section. The factors to be considered are:
(i) The volume, physical, and chemical
characteristics of the wastes, including their potential to migrate through
soil or to volatilize or escape into the atmosphere;
(ii) The attenuative properties of underlying
and surrounding soils or other materials;
(iii) The mobilizing properties of other
materials co-disposed with these wastes; and
(iv) The effectiveness of additional
treatment, design, or monitoring techniques.
(b) The department may determine that
additional design, operating, and monitoring requirements are necessary in
order to reduce the possibility of migration of these wastes to groundwater,
surface water, or air so as to protect human health and the
environment.
(10) Action
leakage rate.
(a) The department must approve
an action leakage rate for surface impoundment units subject to WAC
173-303-650(2)(j) or (k). The action leakage rate is the maximum design flow
rate that the leak detection system (LDS) can remove without the fluid head on
the bottom liner exceeding 1 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 LDS, waste and leachate characteristics,
likelihood and amounts of other sources of liquids in the LDS, 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.).
(b) 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
WAC 173-303-650(4)(d) to an average daily flow rate (gallons per acre per day)
for each sump. Unless the department 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 is closed in accordance with
WAC 173-303-650(6)(b), monthly during the post-closure care period when monthly
monitoring is required under WAC 173-303-650(4)(d).
(11) Response actions.
(a) The owner or operator of surface
impoundment units subject to subsection (2)(j) or (k) of this section must have
an approved response action plan before receipt of waste. 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 (b) of this subsection.
(b) If the flow rate into the leak detection
system exceeds the action leakage rate for any sump, the owner or operator
must:
(i) Notify the department in writing of
the exceedance within seven days of the determination;
(ii) Submit a preliminary written assessment
to the department within fourteen 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;
(iii) Determine to the extent practicable the
location, size, and cause of any leak;
(iv) 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;
(v) Determine any other short-term
and longer-term actions to be taken to mitigate or stop any leaks;
and
(vi) Within thirty days after
the notification that the action leakage rate has been exceeded, submit to the
department the results of the analyses specified in (b) (iii), (iv), and (v) of
this subsection, 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 department a
report summarizing the results of any remedial actions taken and actions
planned.
(c) To make the
leak and/or remediation determinations in (b)(iii), (iv), and (v) of this
subsection, the owner or operator must:
(i)
Assess the source of liquids and amounts of liquids by source;
(ii) Conduct a fingerprint, dangerous
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
(iii) Assess the seriousness of any leaks in
terms of potential for escaping into the environment; or
(iv) Document why such assessments are not
needed.
(12)
Air emission standards. The owner or operator must manage all hazardous waste
placed in a surface impoundment in accordance with the applicable requirements
of 40 C.F.R. Part 264, Subparts AA, BB, and CC, which are incorporated by
reference at WAC
173-303-690
through
173-303-692.
(13) Existing and newly regulated surface
impoundments. The requirements of 3005 (j)(1) and (6) of the Resource
Conservation and Recovery Act (RCRA) of 1976, as amended, are incorporated by
reference. Surface impoundments regulated for the first time by a listing or
characteristic adopted after November 8, 1984, must comply with new unit
requirements or stop dangerous waste activity by four years after the date of
adoption of the new listing or characteristic.
Statutory Authority:
Chapters
70.105 and
70.105D RCW. 09-14-105 (Order
07-12), § 173-303-650, filed 6/30/09, effective 7/31/09. Statutory
Authority:
Chapters
70.105,
70.105D,
15.54 RCW and
RCW
70.105.007. 00-11-040 (Order 99-01), §
173-303-650, filed 5/10/00, effective 6/10/00. Statutory Authority:
Chapters
70.105 and
70.105D RCW. 95-22-008 (Order
94-30), § 173-303-650, filed 10/19/95, effective 11/19/95; 94-01-060
(Order 92-33), § 173-303-650, filed 12/8/93, effective 1/8/94. Statutory
Authority:
Chapters
70.105 and
70.105D RCW, 40 C.F.R. Part 271.3
and RCRA § 3006 ( 42 U.S.C. 3251 ). 91-07-005 (Order 90-42), §
173-303-650, filed 3/7/91, effective 4/7/91. Statutory Authority:
Chapter
70.105 RCW. 88-18-083
(Order 88-29), § 173-303-650, filed 9/6/88; 88-07-039 (Order 87-37),
§ 173-303-650, filed 3/11/88; 86-12-057 (Order DE-85-10), §
173-303-650, filed 6/3/86; 84-09-088 (Order DE 83-36), § 173-303-650,
filed 4/18/84. Statutory Authority:
Chapter
70.105 RCW and
RCW
70.95.260. 82-05-023 (Order DE 81-33), §
173-303-650, filed 2/10/82.