Current through Register Vol. 48, No. 9, September 27, 2024
(a) Any surface impoundment that is not
covered by paragraph (c) of this section or R.61-79.265.221 must have a liner
for all portions of the impoundment (except for existing portions of such
impoundments). 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 Section264.228(a)(1)(a)(1). For impoundments that will be
closed in accordance with Section264.228(a)(2)(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:
(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 paragraph (a) of this section 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 hazardous constituents (see Subpart F Section264.93) into the
groundwater or surface water at any future time. In making such demonstration,
the owner or operator shall consider:
(1) The
nature and quantity of the wastes;
(2) The proposed alternate 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
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 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 260.10 of this chapter
under "existing facility".
(1)
(i) The liner system must include:
(A) 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
(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 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 3 feet (91 cm) of compacted soil material with a
hydraulic conductivity of no more than
1×10-7cm/ sec.
(ii) The liners must comply with paragraphs
(a) (1), (2), and (3) of this section.
(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. This leak detection system 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 leak detection system in this paragraph are satisfied by
installation of a system that is, at a minimum:
(i) Constructed with a bottom slope of one
percent or more;
(ii) Constructed
of granular drainage materials with a hydraulic conductivity of
1×10-1cm/ 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
3×10-4m2/sec or
more;
(iii) 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;
(iv) Designed and
operated to minimize clogging during the active life and post-closure care
period; and
(v) 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.
(3) The owner or operator shall collect and
remove pumpable liquids in the sumps to minimize the head on the bottom
liner.
(4) 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.
(d) The Department may approve
alternative design or operating practices to those specified in paragraph (c)
of this section if the owner or operator demonstrates to the Department that
such design and operating practices, together with location characteristics:
(1) 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 paragraph (c) of this section; and
(2) Will allow detection of leaks of
hazardous constituents through the top liner at least as effectively.
(e) The double liner requirement
set forth in paragraph (c) of this section may be waived by the Department for
any monofill, if:
(1) The monofill contains
only hazardous wastes from foundry furnace emission controls or metal casting
molding sand, and such wastes do not contain constituents which would render
the wastes hazardous for reasons other than the TCLP toxicity characteristics
in R.61-79.261.24; and
(2)
(i)
(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 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 which has been exempted from the requirements of
paragraph (c) of this section 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;
(B) The monofill is located more than
one-quarter mile from an "underground source of drinking water" (as that term
is defined in section 270.2); and
(C) The monofill is in compliance with
generally applicable groundwater monitoring requirements for facilities with
permits under R.61-79 S.C. 44-56-60 or RCRA
section3005(c)(c); or
(ii) The owner or operator demonstrates 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 paragraph (c) of this section if:
(1) The existing unit was constructed in
compliance with the design standards of sections 3004(o)(1)(A)(i) and
(o)(5)(o)(1)(A)(i) and (o)(5) of the Resource Conservation and Recovery Act;
and
(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;
runon; 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 an
outside protective cover to minimize erosion by wind and water. 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 owner or operator shall specify in
the permit application all design and operating practices that are necessary to
ensure that the requirements of this section are satisfied.
(j) A surface impoundment shall be designed
and constructed such that the bottom of any liner system or natural in-place
barrier is at least five (5) feet above the seasonal high water table unless it
can be demonstrated to the Department that adequate protection of the
groundwater can be maintained at a lesser distance.