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Indiana Department of Environmental Management
Office of Land Quality
100 North Senate Avenue
Indianapolis, IN 46204-2241
OLQ Phone: (317) 232-8941
Title: Methane Monitoring Program
Identification Number: WASTE-0056-NPD
Date Originally Effective: March 17, 2005
Dates Revised: March 28, 2007
Other Policies Repealed or Amended: Enclosure D1 Guidance
Citations Affected: 329 IAC 10-20-17
Brief Description of Subject Matter:
In accordance with the Solid Waste Rule 329 IAC 10-20-17, the owner, operator, or permittee of a municipal solid waste landfill (MSWLF) is required to monitor and control the landfill gas generated by their site to prevent methane concentrations from exceeding 25% of the lower explosive limit for methane in MSWLF structures, and the lower explosive limit for methane at the facility boundary. This document provides guidance for content, design considerations, and specifications that should be included in a Methane Monitoring Program.
This nonrule policy document is intended solely as guidance and does not have the effect of law or represent formal Indiana Department of Environmental Management (IDEM) decisions or final actions. This nonrule policy document shall be used in conjunction with applicable laws. It does not replace applicable laws, and if it conflicts with these laws, the laws shall control. This nonrule policy document may be put into effect by IDEM thirty days after presentation to the appropriate board. Pursuant to IC 13-14-11.5, this policy will be available for public inspection for at least 45 days prior to presentation to the appropriate board. If the nonrule policy is presented to more than one board, it will be effective thirty days after presentation to the last. IDEM will submit the policy to the Indiana Register for publication. Revisions to the policy will follow the same procedure of presentation to the board and publication.
In accordance with the Solid Waste Rule 329 IAC 10-20-17, the owner, operator, or permittee of a municipal solid waste landfill (MSWLF) is required to monitor and control the landfill gas generated by their site to prevent methane concentrations from exceeding 25% of the lower explosive limit for methane in MSWLF structures, and the lower explosive limit for methane at the facility boundary. This document provides guidance for content, design considerations, and specifications that will satisfy the commissioner that a Methane Monitoring Program proposal complies with 329 IAC 10-20-17.
This nonrule policy document will be utilized during the commissioner's review of Methane Monitoring Program proposals submitted as required by the Solid Waste Rule for new sites and site expansions. The commissioner shall approve alternatives to the final design as outlined in this guidance if they are demonstrated, to the satisfaction of the commissioner, to provide at least the equivalent protection to human health and the environment. Currently approved Methane Monitoring Programs may continue as approved unless it is determined that the program is ineffective due to physical evidence of gas migration or geological conditions that warrant revision based on 329 IAC 10-20-17(c). Revisions to current Methane Monitoring Programs will follow this guidance only as it is directly supported by the Rule.
Much of the geological information requested in this guidance is available in the site hydrostudy submitted in the permit application under 329 IAC 10-15-4, in subsequent boring information and in the results of the regular ground water sampling.
329 IAC 10-20-17(b) requires MSWLFs to prepare, propose for the commissioner's approval, and implement an approved routine Methane Monitoring Program. The proposal for a facility Methane Monitoring Program should include the following:
329 IAC 10-20-17(c) requires that the type and frequency of methane monitoring be based on the facility's structural and geological conditions. Conditions applicable to the design of the methane monitoring system should be included in the proposal as follows:
1.1 A narrative describing the following landfill conditions:
1.2 A narrative with plans and charts describing the following geological conditions:
329 IAC 10-20-17(a)(1) requires the facility to measure methane gas in MSWLF structures, excluding gas control, leachate collection manholes, or recovery system components.
The Methane Monitoring Program proposal should include the following information:
2.1 A narrative describing the method of methane measurement including:
329 IAC 10-20-17(a)(2) requires the facility to ensure that sub-surface methane gas at the facility boundary does not exceed 100% of the lower explosive limit (LEL) of methane (5%). The facility may make this assurance under one of two systems: Early Warning or Perimeter. A detection in an early warning system allows the facility time to react prior to a violation, while a perimeter system detection automatically triggers a violation. The facility may opt for a mixture of both systems of testing locations within a Methane Monitoring Program. The Methane Monitoring Program should include the following considerations:
3.1 Testing locations under a perimeter system are designed to determine whether gas is migrating across the facility boundary and therefore need to be placed as close as practicable to the facility boundary but not more than fifty (50) feet inside the facility boundary. A detection over the LEL will be considered a transgression of methane across the facility boundary and therefore a violation of 329 IAC 10-20-17(a)(2).
3.2 Testing locations under an early warning system should be as close as possible to the solid waste boundary, however any well between the solid waste boundary and fifty (50) feet from the facility boundary should be considered early warning testing locations.
3.3 All facility boundary testing locations should be spaced on the schedule below. MSWLF structures that are subject to 329 IAC 10-20-17(a)(1) are not intended to be considered in these spacing guidelines.
3.4 329 IAC 10-20-17(c) requires the facility to consider the geology of the site to determine gas migration. Generally, this will require a permanent probe at each test location capable of accessing soil gas at depths identified in 1.2.
3.5 329 IAC 10-21-4 should be used as a general guideline for gas probe installation. While this regulation pertains to ground water monitoring wells, the construction and reporting requirements are similar to gas probes. The major exception is 329 IAC 10-21-4(c)(5)(C), which limits screen length. In the case of gas probes, screen lengths should be specified and justified. IDEM prefers probe screen lengths to be as long as possible, though geological conditions may require specific adjustments.
3.6 The installation of permanent probes may be phased to coincide with cell construction provided the facility has interim measures in place and the approval of IDEM.
3.7 The testing location proposal should include landfill topographic plot plans clearly delineating the following on a scaled map as required by 329 IAC 10-11-2.5 and 329 IAC 10-15-2. Items requested below not applicable to the facility should be noted as such in the text or on the plan.
3.8 The Methane Monitoring Program proposal should include a description of the system for measuring the methane gas concentration including:
*Please be aware that, depending on the method chosen for installing permanent probes, the Department of Natural Resources may require borehole drillers to be certified per 312 IAC 13.
3.9 Testing methods, at each location, should be capable of monitoring methane:
3.10 Additional probes might be needed after a Methane Monitoring Program is approved if evidence of gas migration is found through other means. (Ground water indications of gas migration can include volatile organic compounds and select inorganic compounds in ground water analysis results. Gas might also vent from ground water wells partially screened in unsaturated soils. Gas presence within the ground water well risers should be reported to IDEM based on 329 IAC 10-21-1(f). A facility could be put into an unnecessary ground water corrective action when a replacement well is more warranted.)
3.11 The installation of any device designed to vent landfill gas from the soil should be done in consultation with IDEM. Additional, or replacement, probes may be needed after a Methane Monitoring Program is approved if the function of a detection probe is impaired by nearby soil-gas venting.
329 IAC 10-20-17(c) requires a determination of type and frequency of methane monitoring. The Methane Monitoring Program should include collection method and quality control of landfill gas monitoring data as follows:
4.1 A description of the methods and equipment used to measure the concentration of methane at the landfill. The description should include procedures to ensure minimal air intrusion, calibration check, and employee and public safety. The equipment must be capable of measuring methane gas. It is preferred that oxygen and carbon dioxide percentages also be measured.
4.2 A sample of the form used to record data that includes the following field information:
4.3 Methane monitoring should be done:
4.4 Measurements taken within the top few feet of the ground surface have typically proven to be an ineffective measurement of landfill gas migration. Such methods might not take the hydrogeologic conditions into account as is required in 329 IAC 10-20-17(c).
329 IAC 10-20-17(d) requires an MSWLF facility to follow a schedule of remedial measures if methane gas criteria are exceeded. The Methane Monitoring Program should include a contingency plan, as required in all current permits, that allows the facility to follow pre-developed steps for the initial response to a violation of gas criteria. This general remedial contingency plan should be designed to be performed without acquiring formal approval of a modification to the permit. Performance of any such remedial work should be done in consultation with the Geology Section. Completion of an approved contingency plan should satisfy the implementation portion of 329 IAC 10-20-17(d)(4). The Methane Monitoring Program should include an explanation of how the facility will comply with 329 IAC 10-20-17(d) with a contingency plan including the items in 5.1 and 5.2 below:
5.1 Notification information including:
5.2 A general narrative including:
5.3 If the methane limits specified in 329 IAC 10-20-17(a) are exceeded:
5.4 Facilities with early warning systems, as described under 3.2, should include contingency plans specific to the system design. Such contingencies may include:
329 IAC 10-20-17(d)(4) requires a facility to propose a remedy within sixty (60) days of detecting levels of methane that exceed the limits defined in 329 IAC 10-20-17(a). The proposal that is inserted in the facility operating record should include both the work that has already been done, and any additional work that is deemed necessary. In the event that remediation tactics are ineffective and probe concentrations continue to exceed the regulatory limits of 329 IAC 10-20-17 for two quarters of monitoring, a gas venting system or a gas extraction system proposal for the facility should be submitted to IDEM for review. For more information on landfill gas venting systems, refer to the IDEM guidance document entitled "Methane Gas Venting System"
329 IAC 10-20-17(b) requires the Methane Monitoring Program to be a long-term routine program. Monitoring devices should be properly protected and maintained to ensure continued compliance with the approved Methane Monitoring Program. Owing to time constraints between monitoring events, submittal of the plans and details of repairs and replacements of monitoring devices in the approved Methane Monitoring Program due to accidental damage may be done after the work is completed as allowed under 329 IAC 10-3-3(b).
7.1 If a probe is damaged, it should be fixed or replaced before the next monitoring event.
7.2 If a gas probe is damaged beyond repair, the probe should be properly abandoned and a replacement probe be installed within ten (10) feet of the original. A description of the work done should be submitted as part of the approved Methane Monitoring Program. A probe will automatically be considered ‘replaced' if it is installed within ten (10) feet of the original. If it is installed farther than ten (10) feet from the original, it will be considered a relocation, and a modification under 329 IAC 10-3-3(c), unless the new location is approved as a replacement by the Geology Section.
7.3 Abandonment procedures should follow 329 IAC 10-21-1(i). A description of the abandonment procedure should be submitted as part of the approved Methane Monitoring Program.
Changes in an approved Methane Monitoring Program are, in effect, a modification to the permit. A change in the program may be prompted by such things as facility activities requiring probes to be relocated or any remedial work required under 329 IAC10-20-17 (d). Any change to the Methane Monitoring Program, excluding maintenance, repair or replacement, must be submitted to IDEM prior to implementation under 329 IAC 10-3-3.
9.1 A Methane Monitoring Program is required (329 IAC 10-20-17(b)(1)) to be submitted, per the schedule devised in the facility permit, for approval prior to implementation and should include the information described in this document.
9.2 An As-Built Report will be required, as part of the pre-operational conditions of applicable solid waste permits. An as-Built Report for an approved revision to a Methane Monitoring Program needs to be submitted sixty (60) days after the implementation of the revision. This report should include such information that is gathered during the implementation of the Methane Monitoring Plan such as: probe construction, boring logs and a brief narrative, with geological cross-sections, on the probable interconnection between the screened interval of each probe and the zones targeted for screening in the Plan under 1.2.
9.3 Quarterly data are required (329 IAC 10-20-8(a)(10)) to be compiled and stored in the facility operating record. The Commissioner may request submittal or inspection of these data at any time (329 IAC 10-20-8(b)). Information in the quarterly data should include the items listed in 4.2.
9.4 Compilation of exceeding data and steps taken to protect human health are required by 329 IAC 10-20-17(d)(3) to be placed in the operating record within seven (7) days of a gas exceedance.
9.5 Within sixty (60) days of a detection of greater than 25% LEL (1.25% methane gas) in MSWLF structures or 100% LEL (5% methane gas) at the facility boundary, 329 IAC 10-20-17(d)(4) requires the following:
9.6 Implementation of any remediation plan required under 329 IAC 10-20-17(d)(4) is considered a change to, or revision of, the Methane Monitoring Program and therefore a modification to the permit under 329 IAC 10-3-3. Items that require expediency to protect human health and the environment may be approved verbally, and in consultation, with the IDEM Geology Section until a formal revision of the Methane Monitoring Program can be compiled and submitted for approval.
For questions regarding this guidance contact Bill Robinson at 317/233-1055.