Recovery and Disposal of Contaminated Ground Water

Background:

The aquifer under the plant has contaminates which may have come from operation of a plant landfill, plant operations or from neighboring plants who used the contaminate products in their operations. Removal of the ground water to treat and release it to a surface stream has a NPDES Permit.

The analysis of the ground water cannot distinguish the source. Monitor wells around the landfill have not detected any leakage in the last fifteen years. The landfill was renovated fifteen years ago and a liner was installed at that time. Monitoring data before the liner is not available.

Both of the neighboring plants have used the solvent in the past during maintenance and have no record of offsite disposal for the used solvent. The recovery wells are located to capture the plume. Two wells are cross gradient and approximately a mile ease of the plant. One well has low-level contamination in it, and is located on the plant east boundary which is cross gradient from the landfill. In addition, records were inconclusive as to the dates of operation and what was put into the landfill.

The ground water contaminates are chlorinated solvents at low levels. These are materials produced at the plant but as noted above the detections beyond the plant boundary are cross gradient and in the case of two of the wells are at some distance from plant potential sources.

Issue:

In the Memorandum “Management of RCRA Remediation Waste Under RCRA,” the agency articulated:

“Where a facility owner/operator makes a good faith effort to determine if a material is a listed hazardous waste but cannot make such a determination because documentation regarding a source of contamination, contaminant, or waste is unavailable or inconclusive, EPA has stated that one may assume the source, contaminant, or waste is not a listed hazardous waste and, therefore, provided the material in question does not exhibit a characteristic of hazardous waste, RCRA requirements do not apply.”

In the proposal preamble to the HWIR-Media, 61 FR 18805, April 29, 1996, the concept was expanded to cover dates of waste disposal:

“i.e., if after a good faith effort to determine dates of disposal a facility owner/operator is unable to make such a determination because documentation of dates of disposal is unavailable or inconclusive, one may assume disposal occurred prior to the effective date of applicable land disposal restrictions.”

The two interceptor wells a mile east of the plant are likely cross gradient and not likely to have plant originating contaminates will have an NPDES permit to release the recovered ground water to the near by natural drainage. The closer well is to be recovered and brought to the plant for use in the cooling water system. None of the three wells has current concentrations of solvents above the toxic characteristic list found in 261.24.

Regulatory Citation:

The memorandum “Management of Remediation waste Under RCRA and discussions with the RCRA Hot line and corporate attorneys.

Interpretation:

Disposal of recovered ground water can be done by use of the NPDES permit as long s constituents meet permit requirements without RCRA implications. The well closer to the plant may be brought to the plant for use as long as the constituents of concern maintain levels below the TCLP limits.