Current through Register Vol. 48, No. 38, September 20, 2024
a) Any surface impoundment that is not
covered by subsection (c) or 35 Ill. Adm. Code
725.321
must have a liner for all portions of the impoundment (except for existing
portions of such 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 Section
724.328(a)(1).
For impoundments that will be closed in accordance with Section
724.328(a)(2),
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 as follows:
1) 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;
2)
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
3) Installed to cover all surrounding earth
likely to be in contact with the waste or leachate.
b) The owner or operator will be exempted
from the requirements of subsection (a) if the Board grants an adjusted
standard pursuant to Section 28.1 of the Act and 35 Ill. Adm. Code 101 and 104.
The level of justification is a demonstration by the owner or operator that
alternative design or operating practices, together with location
characteristics, will prevent the migration of any hazardous constituents (see
Section
724.193)
into the groundwater or surface water at any future time. In deciding whether
to grant an adjusted standard, the Board will consider the following:
1) The nature and quantity of the
wastes;
2) The proposed alternative
design and operation;
3) 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
4) All other factors that 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 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 35 Ill. Adm. Code
720.110, under the
definition of "existing facility".
1) Liner
Requirements
A) The liner system must include
the following:
i) A top liner designed and
constructed of materials (e.g., a geomembrane) to prevent the migration of
hazardous constituents into such liner during the active life and post-closure
care period; and
ii) 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 hazardous 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 hazardous constituents if
a breach in the upper component were to occur. The lower component must be
constructed of at least three feet (91 cm) of compacted soil material with a
hydraulic conductivity of no more than 1 x 10-7
cm/sec.
B) The liners
must comply with subsections (a)(1), (a)(2), and (a)(3).
2) 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 (LDS). This LDS must be capable of detecting, collecting, and
removing leaks of hazardous 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 LDS
in this subsection (c) are satisfied by installation of a system that is, at a
minimum, as follows:
A) It is constructed with
a bottom slope of one percent or more;
B) It is 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) It is 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) It is designed and
operated to minimize clogging during the active life and post-closure care
period; and
E) It is 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 sumps. 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.
3) The owner or operator must
collect and remove pumpable liquids in the sumps to minimize the head on the
bottom liner.
4) The owner or
operator of a LDS that is not located completely above the seasonal high water
table must demonstrate that the operation of the LDS will not be adversely
affected by the presence of groundwater.
d) Subsection (c) will not apply if the owner
or operator demonstrates to the Agency, and the Agency finds for such surface
impoundment, that alternative design or operating practices, together with
location characteristics, will do the following:
1) It will prevent the migration of any
hazardous constituent into the groundwater or surface water at least as
effectively as the liners and leachate collection and removal system specified
in subsection (c); and
2) It will
allow detection of leaks of hazardous constituents through the top liner at
least as effectively.
e)
The double liner requirement set forth in subsection (c) may be waived by the
Agency for any monofill, if the following is true of the unit:
1) The monofill contains only hazardous
wastes from foundry furnace emission controls or metal casting molding sand,
and such wastes do not contain constituents that would render the wastes
hazardous for reasons other than the toxicity characteristic in 35 Ill. Adm.
Code
721.124;
and
2) Design and Location
A) Liner, location, and groundwater
monitoring.
i) The monofill has at least one
liner for which there is no evidence that such liner is leaking. For the
purposes of this subsection (e), the term "liner" means a liner designed,
constructed, installed, and operated to prevent hazardous 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 hazardous 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 that has been exempted from the requirements of subsection
(c) on the basis of a liner designed, constructed, installed, and operated to
prevent hazardous 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;
ii) The monofill
is located more than one-quarter mile from an "underground source of drinking
water" (as that term is defined in 35 Ill. Adm. Code
702.110);
and
iii) The monofill is in
compliance with generally applicable groundwater monitoring requirements for
facilities with permits; or
B) The owner or operator demonstrates to the
Board that the monofill is located, designed, and operated so as to assure that
there will be no migration of any hazardous constituent into groundwater or
surface water at any future time.
f) The owner or operator of any replacement
surface impoundment unit is exempt from subsection (c) if the following is true
of the unit:
1) The existing unit was
constructed in compliance with the design standards of 35 Ill. Adm. Code
724.321(c), (d), and (e); and
BOARD NOTE: The cited subsections implemented the design
standards of sections 3004 (o)(1)(A)(i) and (o)(5) of the Resource Conservation
and Recovery Act (
42
USC 6924(o)(1)(A)(i) and
(o)(5)) .
2) There is no reason to believe that the
liner is not functioning as designed.
g) 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.
h) A surface
impoundment must have dikes that are designed, constructed, and maintained with
sufficient structural integrity to prevent massive failure of the dikes. In
ensuring structural integrity, it must not be presumed that the liner system
will function without leakage during the active life of the unit.
i) The Agency must specify in the permit all
design and operating practices that are necessary to ensure that the
requirements of this Section are satisfied.
