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28 October 1997 AGE-NC Project No. 95-0103 Page '.) of 3 UNIT CONDITIONS AND OPERATIONS • Repairs made to the King-Buck soil vapor extraction (SVE) unit during the past quarter included the overhaul of the pneumatic blower and electric motor, and repair of a manufacturing defect affecting the control panel of the SVE unit, thereby increasing the operating time of the SVE unit. • This SVE unit is equipped with a natural gas ignited pre-heater, which is fed oxygen from the vent gas pulled from the vapor extraction veils. Due to overall low oxygen concentrations in the vent gas, a small quantity of ambient air must be introduced into the SVE combustion train to allow the pre-heater to remain ignited. >~ai4lre of the pre-heater flarne will cause a shut down of the SVE unit. The ambient air or makeup gas introduced to maintain combustion, a result of the design limitations of the SVE unit, reduces the o,,erall vacuum exerted by the SVE unit, thereby reducing the zone of influence of each well and pulling hydrocarbons more slowly from the vadose zone. The frailties of the SVE unit have increased the support time required to observe and maintain the continual operation of the SVE unit beyond that initially anticipated. • Over the later portion of the month of September and through the month of October 1997, -- the SVE unit has operated with less than t elve lours of non-operational time. Through the third quarter of 1997, a total of 5461 lbs. or 87 gallons of hydrocarbons as gasoline were removed by the SVE unit. The mass calculations are included in the {quarterly Report for August 1997. DISCUSSION • The recent rise in ground water at the site has reduced the effectiveness of the soil vapor extraction system, limiting the zone of vapor removal to a Iow permeable silt/clay and increasing the volume of impacted soil to be addressed by the 1AS system. The new site conditions will increase the time required to remove the major portion of the hydrocarbon mass from the site. Noting that the unit has currently not operated with a stable status for more than thirty days,a review of the SVE effectiveness and expected duration is anticipated for March of 1998, to allow for a minimum of six months of stable operation. • The reported utility operational costs have been approximately $1,000 for the operation of the SVE unit and 1AS ground water system. Based on observed operating costs for similar SVE/IAS technologies at other remediation sites, this utility cost is reasonable for the removal of the estimated quantity of hydrocarbons from the Chapin site. Additionally; the overall cleanup costs for this site have been minimized by the utilization of this King-Buck Advanced CeoEnvironmental,Inc.