Current through Register Vol. 48, No. 38, September 20, 2024
a)
During the closure period the owner or operator must do the following:
1) It must continue all operations (including
pH control) necessary to maximize degradation, transformation, or
immobilization of hazardous constituents within the treatment zone, as required
under Section
724.373(a),
except to the extent such measures are inconsistent with subsection
(a)(8);
2) It must continue all
operations in the treatment zone to minimize run-off of hazardous constituents,
as required under Section
724.373(b);
3) It must maintain the run-on control system
required under Section
724.373(c);
4) It must maintain the run-off management
system required under Section
724.373(d);
5) It must control wind dispersal of
hazardous waste if required under Section
724.373(f);
6) It must continue to comply with any
prohibitions or conditions concerning growth of food-chain crops under Section
724.376;
7) It must continue unsaturated zone
monitoring in compliance with Section
724.378,
except that soil-pore liquid monitoring may be terminated 90 days after the
last application of waste to the treatment zone; and
8) It must establish a vegetative cover on
the portion of the facility being closed at such time that the cover will not
substantially impede degradation, transformation, or immobilization of
hazardous constituents in the treatment zone. The vegetative cover must be
capable of maintaining growth without extensive maintenance.
b) For the purpose of complying
with Section
724.215,
when closure is completed the owner or operator may submit to the Agency
certification by an independent qualified soil scientist, in lieu of a
qualified Professional Engineer, that the facility has been closed in
accordance with the specifications in the approved closure plan.
c) During the post-closure care period the
owner or operator must do the following:
1)
It must continue all operations (including pH control) necessary to enhance
degradation and transformation and sustain immobilization of hazardous
constituents in the treatment zone to the extent that such measures are
consistent with other post-closure care activities;
2) It must maintain a vegetative cover over
closed portions of the facility;
3)
It must maintain the run-on control system required under Section
724.373(c);
4) It must maintain the run-off management
system required under Section
724.373(d);
5) It must control wind dispersal of
hazardous waste if required under Section
724.373(f);
6) It must continue to comply with any
prohibitions or conditions concerning growth of food-chain crops under Section
724.376; and
7) It must continue
unsaturated zone monitoring in compliance with Section 724.378, except that
soil-pore liquid monitoring may be terminated 90 days after the last
application of waste to the treatment zone.
d) The owner or operator is not subject to
regulation under subsections (a)(8) and (c) if the Agency finds that the level
of hazardous constituents in the treatment zone soil does not exceed the
background value of those constituents by an amount that is statistically
significant when using the test specified in subsection (d)(3). The owner or
operator may submit such a demonstration to the Agency at any time during the
closure or post-closure care periods. For the purposes of this subsection (d),
the owner or operator must do the following:
1) The owner or operator must establish
background soil values and determine whether there is a statistically
significant increase over those values for all hazardous constituents specified
in the facility permit under Section
724.371.
A) Background soil values may be based on a
one-time sampling of a background plot having characteristics similar to those
of the treatment zone.
B) The owner
or operator must express background values and values for hazardous
constituents in the treatment zone in a form necessary for the determination of
statistically significant increases under subsection (d)(3).
2) In taking samples used in the
determination of background and treatment zone values, the owner or operator
must take samples at a sufficient number of sampling points and at appropriate
locations and depths to yield samples that represent the chemical make-up of
soil that has not been affected by leakage from the treatment zone and the soil
within the treatment zone, respectively.
3) In determining whether a statistically
significant increase has occurred, the owner or operator must compare the value
of each constituent in the treatment zone to the background value for that
constituent using a statistical procedure that provides reasonable confidence
that constituent presence in the treatment zone will be identified. The owner
or operator must use a statistical procedure that does the following:
A) It is appropriate for the distribution of
the data used to establish background values; and
B) It provides a reasonable balance between
the probability of falsely identifying hazardous constituent presence in the
treatment zone and the probability of failing to identify real presence in the
treatment zone.
e) The owner or operator is not subject to
regulation under Subpart F if the Agency finds that the owner or operator
satisfies subsection (d) and if unsaturated zone monitoring under Section
724.378
indicates that hazardous constituents have not migrated beyond the treatment
zone during the active life of the land treatment unit.
