Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 811 - STANDARDS FOR NEW SOLID WASTE LANDFILLS › Subpart C - PUTRESCIBLE AND CHEMICAL WASTE LANDFILLS › Section 811.319 - Groundwater Monitoring Programs

Current through Register Vol. 48, No. 28, July 12, 2024
a)
				Detection Monitoring Program. Any use of the term maximum allowable predicted
				concentration in this Section is a reference to Section
				811.318(c).
				The operator must implement a detection monitoring program in accordance with
				the following requirements:
1) Monitoring
				Schedule and Frequency
A) The monitoring
				period must begin as soon as waste is placed into the unit of a new landfill or
				before September 18, 1991 for an existing landfill. Monitoring must continue
				for a minimum period of 15 years after closure, or in the case of MSWLF units,
				a minimum period of 30 years after closure, except as otherwise provided by
				subsection (a)(1)(C). The operator must sample all monitoring points for all
				potential sources of contamination on a quarterly basis except as specified in
				subsection (a)(3), for a period of five years from the date of issuance of the
				initial permit for significant modification under 35 Ill. Adm. Code
				814.104
				or a permit for a new unit under 35 Ill. Adm. Code
				813.104.
				After the initial five-year period, the sampling frequency for each monitoring
				point must be reduced to a semi-annual basis, provided the operator has
				submitted the certification described in 35 Ill. Adm. Code
				813.304(b).
				Alternatively, after the initial five-year period, the Agency must allow
				sampling on a semi-annual basis if the operator demonstrates that monitoring
				effectiveness has not been compromised, that sufficient quarterly data has been
				collected to characterize groundwater, and that leachate from the monitored
				unit does not constitute a threat to groundwater. For the purposes of this
				Section, the source must be considered a threat to groundwater if the results
				of the monitoring indicate either that the concentrations of any of the
				constituents monitored within the zone of attenuation is above the maximum
				allowable predicted concentration for that constituent or, for existing
				landfills, subject to Subpart D of 35 Ill. Adm. Code 814, that the
				concentration of any constituent has exceeded the applicable standard at the
				compliance boundary as defined in 35 Ill. Adm. Code
				814.402(b)(3).
B) Beginning 15 years after closure of the
				unit, or five years after all other potential sources of discharge no longer
				constitute a threat to groundwater, as defined in subsection (a)(1)(A), the
				monitoring frequency may change on a well by well basis to an annual schedule
				if either of the following conditions exist. However, monitoring must return to
				a quarterly schedule at any well if a statistically significant increase is
				determined to have occurred in accordance with Section
				811.320(e),
				in the concentration of any constituent with respect to the previous sample.
i) All constituents monitored within the zone
				of attenuation have returned to a concentration less than or equal to ten
				percent of the maximum allowable predicted concentration; or
ii) All constituents monitored within the
				zone of attenuation are less than or equal to their maximum allowable predicted
				concentration for eight consecutive quarters.
C) Monitoring must be continued for a minimum
				period of: 30 years after closure at MSWLF units, except as otherwise provided
				by subsections (a)(1)(D) and (a)(1)(E); five years after closure at landfills,
				other than MSWLF units, which are used exclusively for disposing waste
				generated at the site; or 15 years after closure at all other landfills
				regulated under this Part. Monitoring, beyond the minimum period, may be
				discontinued under the following conditions:
i) No statistically significant increase is
				detected in the concentration of any constituent above that measured and
				recorded during the immediately preceding scheduled sampling for three
				consecutive years, after changing to an annual monitoring frequency;
				or
ii) Immediately after
				contaminated leachate is no longer generated by the unit.
D) The Agency may reduce the groundwater
				monitoring period at a MSWLF unit upon a demonstration by the owner or operator
				that the reduced period is sufficient to protect human health and
				environment.
E) An owner or
				operator of a MSWLF unit must petition the Board for an adjusted standard in
				accordance with Section
				811.303, if the
				owner or operator seeks a reduction of the post-closure care monitoring period
				for all of the following requirements:
i)
				Inspection and maintenance (Section
				811.111
				);
ii) Leachate collection (Section
				811.309
				);
iii) Gas monitoring (Section
				811.310);
				and
iv) Groundwater monitoring
				(Section 811.319 ).
BOARD NOTE: Changes to subsections (a)(1)(A), (a)(1)(C),
				  (a)(1)(D), and (a)(1)(E) are derived from
				  40 CFR
				  258.61.