Chem-Dyne Site

Hamilton, Ohio

The Chem-Dyne Site was operated as a hazardous waste treatment plant until closure by the U.S. Environmental Protection Agency and the Ohio Environmental Protection Agency. Spills and dumping of chemicals on the surface of the sand-gravel aquifer had created a plume of contaminated groundwater extending over 40 acres. The remedial plan called for pumping and treating the contaminated water and injecting a portion of the treated water to increase flushing in the aquifer. SSP&A designed and supervised the construction of 25 monitoring wells, 36 piezometers, 18 shallow extraction wells, 7 intermediate extraction wells and 8 injection wells. The system began operating in February 1987, and through 1992 an average of nearly one million gallons per day were pumped and treated, with over one-third of the treated water re-injected. The balance of the treatment water was discharged to the Ford Hydraulic Canal, which flows into the Great Miami River.

In October 1992, a chemical assessment conducted by SSP&A showed that the plume had been sufficiently diluted to the point that water from the treatment plant could be discharged directly to surface water, without the need for injection. The injection wells were shut down at this time. The contaminant load from the treated water currently meets the applicable NPDES limits and is discharged into the Ford Hydraulic Canal.

SSP&A continued to monitor withdrawal rates, well performance, water-level responses and quality changes and prepared an annual report on water-level and water-quality changes through 2008. SSP&A also recommended and supervised redevelopment of extraction wells affected by the growth of iron bacteria and advises on the amount and distribution of withdrawals from the extraction wells.

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