Section 200. Control of decomposition gases

Owners or operators of solid waste disposal facilities shall develop a gas management plan in accordance with this section. Venting and control of decomposition gases shall be implemented for sanitary and other landfills in order to protect the landfill cap and prevent migration into structures or beyond the facility boundary, subject to exceptions at 9VAC20-81-130 K. The contents of the plan shall also reflect the requirements contained in 40 CFR 60.33c and 40 CFR 60.750, (Standards of performance for new and guidelines for control of existing municipal solid waste landfills) and 9VAC5-40-5800, as applicable.

A. General requirements.

1. To provide for the protection of public health and safety, and the environment, the operator shall ensure that decomposition gases generated at a landfill are controlled during the periods of operation, closure and postclosure care, in accordance with the following requirements:

a. The concentration of methane gas generated by the landfill shall not exceed 25% of the lower explosive limit (LEL) for methane in landfill structures (excluding gas control or recovery system components); and

b. The concentration of methane gas migrating from the landfill shall not exceed the lower explosive limit for methane at the facility boundary.

2. The program implemented pursuant to subsections B through E of this section shall continue throughout the active life of the landfill and the closure and postclosure care periods or until the operator receives written authorization by the department to discontinue. Authorization to cease gas monitoring and control shall be based on a demonstration by the operator that there is no potential for gas migration beyond the facility boundary or into landfill structures.

3. Gas monitoring and control systems shall be modified, during the closure and postclosure maintenance period, to reflect changing on-site and adjacent land uses. Postclosure land use at the site shall not interfere with the function of gas monitoring and control systems.

4. The operator may request a reduction of monitoring or control activities based upon the results of collected monitoring data. The request for reduction of monitoring or control activities shall be submitted in writing to the department.

B. The operator shall implement a gas monitoring program at the landfill in accordance with the following requirements:

1. The gas monitoring network shall be designed to ensure detection of the presence of decomposition gas migrating beyond the landfill facility boundary and into landfill structures.

2. The monitoring network shall be designed to account for the following specific site characteristics, and potential migration pathways or barriers, including, but not limited to:

a. Local soil and rock conditions;

b. Hydrogeological and hydraulic conditions surrounding the landfill;

c. Locations of buildings and structures relative to the waste deposit area;

d. Adjacent land use, and inhabitable structures within 1,000 feet of the landfill facility boundary;

e. Manmade pathways, such as underground construction; and

f. The nature and age of waste and its potential to generate decomposition gas.

3. Owners or operators of certain large sanitary landfills and landfills located in nonattainment areas may be required to perform additional monitoring as provided in 40 CFR 60.33c, 40 CFR 60.750, and 9VAC5-40-5800.

4. At a minimum, the gas monitoring frequency shall be quarterly. The department may require more frequent monitoring at locations where monitoring results indicate gas migration or gas accumulation in devices or structures designed to detect migrating gas.

C. Gas Remediation.

1. When the gas monitoring results indicate concentrations of methane in excess of the action levels, 25% of the lower explosive limit (LEL) for methane in landfill structures (excluding gas control or recovery system components) or 80% of the LEL for methane at the facility boundary, the operator shall:

a. Take all immediate steps necessary to protect public health and safety including those required by the contingency plan.

b. Notify the department in writing within five working days of learning that action levels have been exceeded, and indicate what has been done or is planned to be done to resolve the problem.

2. When the gas monitoring results indicate concentrations of methane in excess of the compliance levels, 25% of the LEL for methane in landfill structures (excluding gas control or recovery system components) or the LEL for methane at the facility boundary, the operator shall, within 60 days of detection, implement a remediation plan for the methane gas releases and submit it to the department for modification of the landfill permit. The plan shall describe the nature and extent of the problem and the proposed remedy. The plan shall include an implementation schedule specifying timeframes for implementing corrective actions, an evaluation of the effectiveness of such corrective actions, and milestones for proceeding in implementation of additional corrective actions, if necessary to reestablish compliance.

3. A gas remediation system shall:

a. Prevent methane accumulation in onsite structures.

b. Reduce methane concentrations at monitored facility boundaries to below compliance levels in the timeframes specified in the gas remediation plan.

c. Provide for the collection and treatment and/or disposal of decomposition gas condensate produced at the surface. Condensate generated from gas control systems may be recirculated into the landfill provided the landfill complies with the liner and leachate control systems requirements of this part. Condensate collected in condensate traps and drained by gravity into the waste mass will not be considered recirculation.

4. Extensive systems to control emissions of nonmethane organic compounds may be required under the Clean Air Act (40 CFR 60.33c and 40 CFR 60.750) and 9VAC5-40-5800. Facilities that are required to construct and operate systems designed to comply with those regulations will be considered to be in compliance with the requirements of subdivisions C 3 a and b of this subsection, unless monitoring data continues to indicate an exceedance of compliance levels. Gas control systems also may be subject to the Virginia Permits for Stationary Sources Program 9VAC5-80 or other state air pollution control regulations.

5. The landfill shall notify the department of an exceedance of the compliance level or unusual condition that may endanger human health and the environment in accordance with 9VAC20-81-530 C 3, such as when an active gas remediation system is no longer operating in such a manner as to maintain compliance with this section.

D. Odor management.

1. When an odor nuisance or hazard is created under normal operating conditions and upon notification from the department, the permittee shall, within 90 days, develop and implement an odor management plan to address odors that may impact citizens beyond the facility boundaries. The permittee shall place the plan in the operating record and a copy shall be submitted to the department for its records. Odor management plans developed in accordance with Virginia Air Regulations, 9VAC5-40-140, 9VAC5-50-140 or other state air pollution control regulations will suffice for the provisions of this subsection.

2. The plan shall identify a contact at the landfill that citizens can notify about odor concerns.

3. Facilities shall perform and document an annual review and update the odor management plan, as necessary, to address ongoing odor management issues.

E. Recordkeeping. The owner or operator shall keep the records of the results of gas monitoring and any gas remediation issues throughout the active life of the landfill and the postclosure care period. The records shall include:

1. The concentrations of the methane as measured at each probe and within each onsite structure;

2. The documentation of date, time, barometric pressure, atmospheric temperatures, general weather conditions, and probe pressures;

3. The names of sampling personnel, apparatus utilized, and a brief description of the methods used;

4. A numbering system to correlate monitoring results to a corresponding probe location; and

5. Monitoring and design records for any gas remediation or control system.

Historical Notes

Derived from Volume 27, Issue 12, eff. March 16, 2011.

Statutory Authority

§ 10.1-1402 of the Code of Virginia; 42 USC § 6941 et seq.; 40 CFR Part 258.