(a) Any surface impoundment that is not covered by
subsection (c) of this section or 40 Code of Federal Regulations (CFR) §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 §335.169(a)(1) of this title (relating
to Closure and Post-Closure Care (Surface Impoundments)). For impoundments
that will be closed in accordance with §335.169(a)(2) of this
title, 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 subsections (a) and (j) of this section if the commission
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 §335.159
of this title (relating to Hazardous Constituents)) into the groundwater
or surface water at any future time. In deciding whether to grant
an exemption, the commission will consider:
(1) the nature and quantity of the wastes;
(2) the adopted 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 meet the requirements of 40 CFR §264.221(c), as amended
through July 14, 2006 (71 FR 40254).
(d) The executive director may approve alternative
design or operating practices to those specified in subsection (c)
of this section if the owner or operator demonstrates to the executive
director that he meets the requirements of 40 CFR §264.221(d),
as amended through January 29, 1992 (57 FR 3462).
(e) The double liner requirement set forth in subsection
(c) of this section may be waived by the commission for any monofill
which 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 toxicity characteristics in 40 CFR §261.24, and is in
compliance with either of the following requirements:
(1) the monofill:
(A) has at least one liner for which there is no evidence
that such liner is leaking. For the purposes of this subsection, 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 subsection (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) is located more than 1/4 mile from an underground
source of drinking water (as that term is defined in §331.2 of
this title (relating to Definitions)); and
(C) is in compliance with groundwater monitoring requirements
of this subchapter; or
(2) 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 subsection (c) of this section if:
(1) The existing unit was constructed in compliance
with the design standards of Resource Conservation and Recovery Act, §3004(o)(1)(A)(i)
and (o)(5); 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;
run-off, 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 commission will specify in the permit all design
and operating practices that are necessary to ensure that the requirements
of this section are satisfied.
(j) A surface impoundment (except for an existing portion
of a surface impoundment) that will be closed in accordance with §335.169(a)(2)
of this title must have an additional liner to that required in subsection
(a) of this section which:
(1) prevents any migration of wastes out of the impoundment
to the adjacent subsurface soil or groundwater or surface water at
any time prior to the end of the post-closure care period; and
(2) minimizes the rate of migration of wastes out of
the impoundment to the adjacent subsurface soil or groundwater or
surface water so as not to pose a substantial present or potential
hazard to human health and the environment.
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Source Note: The provisions of this §335.168 adopted to be effective May 28, 1986, 11 TexReg 2347; amended to be effective March 18, 1991, 16 TexReg 1369; amended to be effective November 23, 1993, 18 TexReg 8218; amended to be effective February 26, 1996, 21 TexReg 1142; amended to be effective November 15, 2001, 26 TexReg 9135; amended to be effective February 21, 2013, 38 TexReg 978 |