Abstract: Reactant Sand-Fracking: A Pilot Test of an Innovative In Situ Groundwater Remediation Technology for Fractured Bedrock Aquifers

BONDS, CHRIS. L., and DONALD L. MARCUS, EMCON, Burbank, CA

A pilot test of an EMCON proprietary groundwater remediation technology called Reactant Sand-Fracking was conducted at a former industrial site in Newbury Park, California during the spring and fall of 1997. Waste management practices used at the facility during the 1950's and 1960's has led to chlorinated solvent and metal impacts to soil and groundwater beneath the site.

The pilot test utilized hydraulic fracturing equipment to emplace chemically reactive iron foam proppants mixed with viscosifier into three selected bedrock fractures within the test boring under very high pressures. An estimated 300 to 1700 pounds of proppants were injected into each of the three fractures. Water levels in the test boring and two observation wells were continuously monitored during the injections. Bromide tracer monitoring verified that the fracking fluid propagated at least 42 feet away from the injection site during the treatments.

By comparison of before and after discrete sampling and testing data, up to a 98 percent decrease in chlorinated solvents via a reductive dehalogenation reaction, a complete reduction of hexavalent chromium via a reduction reaction, and up to a two order of magnitude increase in fracture hydraulic conductivity has occurred as a result of the treatments. Pump tests indicate a sign)ficant improvement in well productivity from a negligible capacity prior to treatment to about 1.5 gallons per minute after treatment.

Nearly all of the results suggest that Reactant Sand-Fracking could provide a long term alternative and/or augmentation to pump and treat for this and other similar sites.

AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California