ARCHIVED REPORTS_NOTICE OF INTENT FOR INSTALLATION, OPERATION AND MAINTENANCE OF AN OZONE INJECTION GROUNDWATER REMEDIATION SYSTEM

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PURPOSE AND SCOPE OF SERVICES The scope of services presented in this CAP are for the installation, operation and maintenance of a groundwater remediation system utilizing ozone sparging. This CAP was developed to comply with the September 21, 2009, CVRWQCB directive. The groundwater remediation system was designed to address the most heavily impacted groundwater onsite in the shallow and intermediate water-bearing zones. The approximate location of the proposed sparge wells are depicted on the Proposed Ozone- sparge Well Location Map,Figure 4. The scope of services is discussed in the following sections. ' General Process Description The proposed groundwater remediation system will consist of an H2O Engineering ozone-sparge ' system (ozone system) Model No. OSU20-52 [3.8 cubic feet per minute (cfm), 110 volts, 30 amps], Schedule 80 poly-vinyl chloride (PVC) conveyance piping, TeflonTM tubing and 17 ozone-sparge wells. ' Seventeen ozone-sparge wells are proposed to be installed in the vicinity of the former USTs as depicted on Figure 4. Nine sparge points will be set at approximately 40 feet, and eight sparge points ' will be set at approximately 50 feet. The 40- and 50-foot-deep wells will be at alternate locations to optimize the vertical and lateral influence of the ozone. We have assumed a 10-foot-radius of ozone injection influence based on the Site lithology and the results of our AS pilot testing. ' The ozone system cabinet will be mounted on a concrete pad and enclosed within the existing fenced fonder treatment compound.A lean-to or canopy with a sloped roof will be installed over the cabinet to ' provide weather protection. Each sparge point will be connected to the ozone system manifold by 3/8-inch-diameter TeflonTM tubing. The tubing will be routed to each injection point through an outer 1-inch-diameter Schedule 80 PVC conduit. ' The ozone system will be initially programmed to cycle ozone injection between the 17 sparge points approximately four times per day for 20 minutes per point. Each injection cycle will be followed by a 30-minute rest period. Following start-up, the number of cycles and cycle length for any individual injection point can be modified depending on the overall system performance. Ozone-sparge Well Installation Seventeen ozone-sparge wells will be installed as part of the ozone system. Borings for the wells will be drilled using hollow-stem auger (HSA) techniques. The sparge points will be H2O Engineering 1.5-foot- long by 1.5-inch-diameter In-situ Oxidation Points suspended from 1-inch-diameter Schedule 80 flush- threaded PVC casing equipped with Vitone O-rings. Each ozone-sparge well will be constructed with the 1.5-foot-long sparge point situated approximately 0.5 foot off the bottom of the boring. The borings will be advanced to approximate depths of 40 and 50 feet,thus the bottom of the point will be approximately ' 10 or 20 feet below the recent historical low piezometric groundwater surface. Since 1993, the average groundwater depth for the five monitoring wells (MW-1 through MW-3, GWX-1 and VX-1) in the vicinity of the proposed ozone-sparge wells was approximately 31 feet below the top of casing (TOC) with recent groundwater depths ranging from 27 to 30 feet below TOC. A typical ozone-sparge well construction detail is shown on Figure 5. The pre-field and field activities associated with the ozone-sparge well installations are described below. ' Project No.59183-06-02 -4- November 11,2009