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uYi tui cu i(.1 J 1.3"JuOUOu7CJ tCCgG1YCj1J PAGE 05/13 April 25,2001 Page 4 of 5 S HRC Delivery to Contaminated Zone using Direct Push Equipment It is assumed that HRC will be applied at the site using direct push hydraulic equipment- Drive rods are pushed to the bottom of the contaminated saturated zone and then HRC is injected as the rods are withdrawn. The minimum recommended rod size is a 0.625-inch inner diameter. Costs for HRC injection should be obtained from local subcontractors. If necessary, Regenesis can assist in locating qualified HRC injection subcontractors. Budgetary cost estimates for direct push- based injection range from$1,000 to $2,000 per day. Typically, one to two HRC injection points can be completed per hour and up to 20 points can be completed per day, depending on soil type, depths of injection, and subcontractor experience. HRC should be injected using an appropriate pump capable of processing a material with a viscosity of 20,000 centipoise at flow rates of 3 to 10 gallons per minute at pressures ranging from 200 psig to 1,500 psig. Failure to use appropriate equipment could increase field time and result in improper application of the HRC. Regenesis has evaluated a rmraber of pumps and has found that the RE Rupe and the Geoprobe GS-2000 pumps provide suitable volume and pressure. The RE Rupe as well as the GS-2000 pumps can be purchased directly from the manufacturers. RE Rupe Co. can be contacted at (515) 682-7029, while Geoprobe Systems can be reached at (800) 436-7762. The Geoprobe GS-2000 is available for rent through Probe-Lease. Probe-Lease can be reached at (800) 645-2009. Recommended Groundwater Monitoring Program for Pilot/Full Scale Treatment Monitoring of selected wells should be conducted to validate the HRC-based enhancement of reductive dechlorination processes. The monitoring well network would ideally include wells from the following locations: Inside treatment area Provides inkrmadon on geoehemical conditions and contaminant trends induced by HRC Downgradient of treatment area Provides information about residence time effects. Since the contaminant has to be in contact with the electron donor for a given length of time, the actual performance may be evident at downgradient locations for sites with moderate to high groundwater velocities. Upgradient of treatment area Provides a measure of contaminant mass and competing electron acceptor load entering treatment area Background Allows comparison of geocbemical changes induced by addition of HRC. An initial or "baseline" round of sampling should be performed to identify pre-HRC installation groundwater conditions. After application of the HRC, samples can be collected every other month for a six to eight month period. After the initial biodegradation and geoehetnical trends have been identified, the monitoring frequency can be decreased to a quarterly, semiannual, or annual program. J:\14RC\Proposals\GeoSyntcc\Vcrnalis Nitrate Site\Vernalis Pilot Tcst 4-24-Ol.doc