Section 6 - Operation and Maintenance

The SVE systems at AOC-65 will be operated and maintained until the groundwater recharge study is complete in September 2003. Following completion of the initial system check and the radius of influence testing, Parsons will prepare an O&M Plan for the AOC-65 SVE System. The plan will include recommendations for continued operation, monitoring, and maintenance of the SVE system based on site conditions, operation parameters determined during the system check, and manufacture's recommendations. Optimization testing of the SVE test system will be continue during the O&M period. In addition, O&M of the SVE unit will include managing the vapor-phase carbon absorption units and the liquid collected in the system's moisture separation vessel.

Sampling to be conducted during the O & M period includes periodic field screening of soil gas samples, and measurement of pressure response, airflow rates and blower parameters. Field screening soil gas samples will be collected from each VEW and VMP and tested for TVH, oxygen, and carbon dioxide. Pressure responses will be measured at each VMP to evaluate operational influence and system performance. Airflow measurements will be conducted at each VEW to assess system performance and estimate contaminant mass removal rate. Additionally, measurements will be made at the SVE blower for temperature, pressure and airflow to assess blower performance. Data collection requirements for the soil gas and other field measurements are summarized in Table 1.1. Sampling procedures for the soil gas measurements are included in Section 7.4 of this addendum. 

Management of the vapor-phase carbon absorption unit will include periodic monitoring of unit performance, estimation of carbon usage rates, and determining schedules for carbon replacement. Parsons will enter a contractual agreement with a qualified carbon vendor to provide the carbon absorption units as needed for the duration of the SVE operation. Typically, these agreements include provisions for the vendor to replace the activated carbon on an as needed basis. Therefore, it is anticipated that the carbon vendor will be responsible for testing the used carbon material for disposal or recycling purposes. In the event that extraneous circumstances arise and CSSA retains responsibility for disposal of the spent activated carbon, the material would require sampling for waste characterization parameters as indicated in Table 1.1.

Liquids collected the SVE system in the moisture separator will require removal and management on a routine basis during the system operation. This liquid can be expected to contain high concentrations of VOC at the beginning of SVE operations. The VOC concentrations in this liquid will decrease with time as remediation progresses. Management of this liquid will involve removing and transporting the liquid to the GAC unit at Well CS-16 for treatment and discharge. The liquid will be staged in a 500-gallon tank at the GAC and will be processed as needed or quarterly at a minimum. It is anticipated that CSSA will be responsible for management of the waste. This liquid may require periodic sampling for VOC analysis prior to treatment to satisfy discharge requirement. Additional information regarding the management of the liquid from the moisture separator will be developed and included in the SVE O&M Plan to be prepared at a later date.

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