There are two primary types of compliance monitoring for ground water discharge permits:
Best Available Technology (BAT)
The purpose of BAT monitoring is to evaluate the performance of discharge control and containment systems for compliance with permit performance standards. For example, BAT for industrial wastewater ponds and tailings impoundments typically include double synthetic liners with leak detection sumps. BAT monitoring for these systems includes measuring daily fluid levels in leak detection sumps and calculating weekly leakage rates and volumes and comparing these values against permit limits. Other examples of BAT monitoring include measuring pond water levels for compliance with freeboard limits, inspecting floor drain sumps and trenches to ensure free drainage to collection systems, and visual inspection of concrete surfaces for cracks.
Failure to Maintain BAT
In the event that the permittee fails to maintain BAT or otherwise fails to meet BAT standards as required by the permit, the permittee shall submit to the Executive Secretary a notification and description of the failure according to R317-6-6.13 (mechanical problems or discharge system failures). Oral notification shall be given within 24 hours of the permittee’s discovery of the BAT failure, and shall be followed up by written notification within five days of the permittee’s discovery of the BAT failure. Written notification shall include the information necessary for the Executive Secretary to determine whether to initiate a compliance action against the permittee. The Executive Secretary shall not initiate a compliance action if the Executive Secretary determines that the permittee has met the standards for an affirmative defense, as specified in R317-6-6.16.C.3.
Ground Water Quality Monitoring
Ground water quality monitoring is conducted to determine if the facility is in compliance with the permit-specific ground water protection levels. As defined in GW Classes and Protection Levels, ground water protection levels are based on site-specific background concentrations of total dissolved solids and other pollutants. Protection levels are intended to provide an early warning of ground water contamination to allow ample time for the permittee to assess the cause and source of the contamination and implement corrective actions.
Probable Out-of-Compliance Status
A facility is in probable out-of-compliance status when the value of a single analysis of any compliance parameter in any compliance monitoring sample exceeds a ground water protection level or other applicable permit limit. When an exceedance occurs, the facility is required to notify the Executive Secretary in writing within 30 days of receipt of data, and immediately initiate accelerated monitoring for a period of two months or until the compliance status of the facility can be determined. If the permit monitoring frequency is semi-annually, the accelerated monitoring will be done quarterly. If the permit monitoring frequency is quarterly, the accelerated monitoring will be done monthly.
Out-of-compliance status exists when:
- The value for two consecutive samples from a compliance monitoring point exceeds: one or more permit limits; and,
- the background concentration for that pollutant by two standard deviations (the standard deviation and background [mean] being calculated using values for the ground water pollutant at that compliance monitoring point) unless the existing permit limit was derived from the background pollutant concentration plus two standard deviations;
- The concentration value of any pollutant in two or more consecutive samples is statistically significantly higher than the applicable permit limit. The statistical significance shall be determined using the statistical methods described in Statistical Methods for Evaluating Ground Water Monitoring Data from Hazardous Waste Facilities, Vol. 53, No. 196 of the Federal Register, Oct. 11, 1988 and supplemental guidance in Guidance For Data Quality Assessment (EPA/600/R-96/084 January 1998).
Procedure for Out-of-Compliance Status
If a facility is out of compliance the following is required:
- The permittee shall notify the Executive Secretary of the out-of-compliance status within 24 hours after detection of that status, followed by a written notice within 5 days of the detection.
- The permittee shall initiate monthly sampling, unless the Executive Secretary determines that other periodic sampling is appropriate, until the facility is brought into compliance.
- The permittee shall prepare and submit within 30 days to the Executive Secretary a plan and time schedule for assessment of the source, extent and potential dispersion of the contamination, and an evaluation of potential remedial action to restore and maintain ground water quality and insure that permit limits will not be exceeded at the compliance monitoring point and BAT will be reestablished.
- The Executive Secretary may require immediate implementation of the contingency plan submitted with the original ground water discharge permit in order to regain and maintain compliance with the permit limit standards at the compliance monitoring point or to reestablish BAT as defined in the permit.
- Where it is infeasible to re-establish BAT as defined in the permit, the permittee may propose an alternative BAT for approval by the Executive Secretary.