Current through Register Vol. 24-06, March 15, 2024
(1) Applicability.
The regulations in this section apply to owners and operators of facilities
that dispose of dangerous waste in landfills, except as WAC
173-303-600 provides otherwise.
No landfill will be permitted to dispose of EHW, except for the Hanford
facility under WAC
173-303-700.
(2) Design and operating requirements.
(a) Any landfill that is not covered by (h)
of this subsection must have a liner system for all portions of the landfill
(except for an existing portion of a landfill). The liner system must have:
(i) A liner that is designed, constructed,
and installed to prevent any migration of wastes out of the landfill to the
adjacent subsurface soil or groundwater or surface water at anytime during the
active life (including the closure period) of the landfill. The liner must be
constructed of materials that prevent wastes from passing into the liner during
the active life of the facility. The owner or operator must submit an
engineering report with his 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. 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; and
(C) Installed to cover all surrounding earth
likely to be in contact with the waste or leachate; and
(ii) A leachate collection and removal system
immediately above the liner that is designed, constructed, maintained, and
operated to collect and remove leachate from the landfill. The department will
specify design and operating conditions in the permit to ensure that the
leachate depth over the liner does not exceed 30 cm (one foot). The leachate
collection and removal system must be:
(A)
Constructed of materials that are:
(I)
Chemically resistant to the waste managed in the landfill and the leachate
expected to be generated; and
(II)
Of sufficient strength and thickness to prevent failure under the pressures
exerted by overlying wastes, waste cover materials, and by any equipment used
at the landfill; and
(B)
Designed and operated to function without clogging through the scheduled
closure of the landfill.
(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 alternative design and
operating practices, together with location characteristics, will prevent the
migration of any dangerous constituents 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 landfill 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) The owner or operator must
design, construct, operate, and maintain a run-on control system capable of
preventing flow onto the active portion of the landfill during peak discharge
from at least a twenty-five-year storm.
(d) The owner or operator must design,
construct, operate, and maintain a runoff management system to collect and
control at least the water volume resulting from a twenty-four-hour,
twenty-five-year storm.
(e)
Collection and holding facilities (e.g., tanks or basins) associated with
run-on and runoff control systems must be emptied or otherwise managed
expeditiously and in accordance with this chapter after storms to maintain
design capacity of the system.
(f)
If the landfill contains any particulate matter which may be subject to wind
dispersal, the owner or operator must cover or otherwise manage the landfill to
control wind dispersal.
(g) 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.
(h) The owner or
operator of each new landfill unit on which construction commences after
January 29, 1992, each lateral expansion of a landfill unit on which
construction commences after July 29, 1992, and each replacement of an existing
landfill unit that commences reuse after July 29, 1992, must install two or
more liners and a leachate collection and removal system above and between such
liners. "Construction commences" is as defined in WAC
173-303-040 under "existing
facility."
(i) The liner system must:
(A) Include 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) Include 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.
(C) The liners must comply with (a)(i)(A),
(B), and (C) of this subsection.
(ii) The leachate collection and removal
system immediately above the top liner must be designed, constructed, operated,
and maintained to collect and remove leachate from the landfill during the
active life and post-closure care period. The department will specify design
and operating conditions in the permit to ensure that the leachate depth over
the liner does not exceed twelve inches (30.5 cm). The leachate collection and
removal system must comply with (h)(iii) and (iv) 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 subsection 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
10-2 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 10-5
m2/sec or more;
(C) Constructed of materials that are
chemically resistant to the waste managed in the landfill and the leachate
expected to be generated, and of sufficient strength and thickness to prevent
collapse under the pressures exerted by overlying wastes, waste cover
materials, and equipment used at the landfill;
(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 leak detection system 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.
(i) The
department may approve alternative design or operating practices to those
specified in (h) 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 systems
specified in (c) of this subsection; and
(ii) Will allow detection of leaks of
dangerous constituents through the top liner at least as effectively.
(j) The double liner requirement
set forth in (h) 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),
with dangerous waste numbers D004 through D017 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;
(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 3005(c); or
(D)
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.
(k) The owner or
operator of any replacement landfill unit is exempt from (h) of this subsection
if:
(i) The existing unit was constructed in
compliance with the design standards of section 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 or installation,
liners (except in the case of existing portions of landfills exempt from
subsection (2)(a) 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 landfill 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 run-on and runoff control systems;
(ii) Proper functioning of wind dispersal
control systems; and
(iii) The
presence of leachate in and proper functioning of leachate collection and
removal systems.
(c)
(i) An owner or operator required to have a
leak detection system under subsection (2)(h) or (j) 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 semiannually. 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)
Surveying and recordkeeping. The owner or operator of a landfill must maintain
the following items in the operating record required under WAC
173-303-380:
(a) On a map, the exact location and
dimensions, including depth, of each cell with respect to permanently surveyed
benchmarks; and
(b) The contents of
each cell and the approximate location of each dangerous waste type within each
cell.
(6) Closure and
post-closure care.
(a) At final closure of the
landfill or upon closure of any cell, the owner or operator must cover the
landfill or cell with a final cover designed and constructed to:
(i) Provide long-term minimization of
migration of liquids through the closed landfill;
(ii) Function with minimum
maintenance;
(iii) Promote drainage
and minimize erosion or abrasion of the cover;
(iv) Accommodate settling and subsidence so
that the cover's integrity is maintained; and
(v) Have a permeability less than or equal to
the permeability of any bottom liner system or natural subsoils
present.
(b) After final
closure, 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. 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)(h) and (4)(c) of this section, where
such a system is present between double liner systems;
(iii) Continue to operate the leachate
collection and removal system until leachate is no longer detected;
(iv) Maintain and monitor the groundwater
monitoring system and comply with all other applicable requirements of WAC
173-303-645;
(v) Prevent run-on and runoff from eroding or
otherwise damaging the final cover; and
(vi) Protect and maintain surveyed benchmarks
used in complying with subsection (5) of this section.
(c) Reserve.
(7) Special requirements for incompatible
wastes. Incompatible wastes, or incompatible wastes and materials must not be
placed in the same landfill cell, unless WAC
173-303-395(1)(b)
is complied with.
(8) Action leakage rate.
(a) The department must approve an action
leakage rate for landfill units subject to subsection (2)(h) or (j) of this
section. 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 l 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 subsection (2)(h) of this
section 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 monthly during the post-closure care period when monthly monitoring
is required under subsection (9) of this section.
(9) Response actions.
(a) The owner or operator of landfill units
subject to subsection (2)(h) or (j) 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 long-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.
(10)
Special requirements for ignitable or reactive waste.
(a) Except as provided in subsection (8)(b)
of this section, and in WAC
173-303-161, ignitable or
reactive waste must not be placed in a landfill, unless the waste and landfill
meet all applicable requirements for owners and operators of dangerous waste
treatment, storage and disposal facilities contained in this chapter, and:
(i) The resulting waste, mixture, or
dissolution of material no longer meets the definition of ignitable or reactive
waste under WAC
173-303-090(5) or
(7); and
(ii) WAC
173-303-395(1)
is complied with.
(b)
Except for prohibited wastes which remain subject to treatment standards in WAC
173-303-140(2)(a),
ignitable wastes in containers may be landfilled without meeting the
requirements of (a) of this subsection, provided that the wastes are disposed
of in such a way that they are protected from any material or conditions which
may cause them to ignite. At a minimum, ignitable wastes must be disposed of in
nonleaking containers which are carefully handled and placed so as to avoid
heat, sparks, rupture, or any other condition that might cause ignition of the
wastes; must be covered daily with soil or other noncombustible material to
minimize the potential for ignition of the wastes; and must not be disposed of
in cells that contain or will contain other wastes which may generate heat
sufficient to cause ignition of the waste.
(11) Special requirements for hazardous
wastes F020, F021, F022, F023, F026, and F027.
(a) Hazardous wastes F020, F021, F022, F023,
F026, and F027 must not be placed in a landfill unless the owner or operator
operates the landfill in accord 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 the
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 requirements.
(b) The department may determine that
additional design, operating, and monitoring requirements are necessary for
landfills managing hazardous wastes F020, F021, F022, F023, F026, and F027 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.
(12)
Special requirements for containers. Unless they are very small, such as an
ampule, containers must be either:
(a) At
least ninety percent full when placed in the landfill; or
(b) Crushed, shredded, or similarly reduced
in volume to the maximum practical extent before burial in the
landfill.
(13) Disposal
of liquid waste. Special requirements for bulk and containerized liquids are at
WAC 173-303-140(4)(b).
Statutory Authority:
Chapters
70.105 and
70.105D RCW. 09-14-105 (Order
07-12), § 173-303-665, filed 6/30/09, effective 7/31/09; 98-03-018 (Order
97-03), § 173-303-665, filed 1/12/98, effective 2/12/98; 95-22-008 (Order
94-30), § 173-303-665, filed 10/19/95, effective 11/19/95. Statutory
Authority:
Chapter
70.105 RCW. 88-02-057
(Order DE 83-36), § 173-303-665, filed 1/5/88, effective 2/5/88; 86-12-057
(Order DE-85-10), § 173-303-665, filed 6/3/86; 84-09-088 (Order DE 83-36),
§ 173-303-665, filed 4/18/84.