FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

5 . 0 REMEDIATION SYSTEM DESIGN The proposed remediation system will incorporate the use often ( 10) ozone-sparge wells. The locations of these wells are shown on Figure 3. A cross-sectional view of a typical ozone sparging well is included in Appendix B. ASE is assuming a conservative radius of influence of 15-feet based on data from the air-sparging test at the site. The wells were located to destroy hydrocarbons within and downgradient of the former USTs. All ten ports on the ozone generation unit will be utilized. The wells will be drilled with a drill rig equipped with 5-inch diameter hollow-stem augers. The wells will be constructed with 314-1nch diameter PVC well casing. Ozone will be sparged from the casing through a 2-inch diameter by 30-inch long sparge point with 10-50 micron perforations. These sparge points will be placed in the location of the permeable water- bearing zone approximately 15-feet bgs. Lonestar #2116 or finer sand will be placed between the sparge point and the boring from the bottom of the boring to 1-foot above the top of the sparge point. A 0.5-foot thick bentonite layer will be placed between the sandpack and the overlying cement sanitary seal. A Portland cement sanitary seal will be placed above the bentonite layer to prevent surface water from infiltrating into the well. The wellheads will be piped directly into an ozone-sparging manifold, which will then be piped directly to the ozone generator. 5 .2 Ozone Generator The system will utilize a C-Sparger System manufactured by KVA Associates. The C-Sparger System is a compact unit that generates an air/ozone mixture on-site. The unit will then pump the air/ozone mixture through ten ports one port at a time on a cycle set by a timer. The air/ozone flow is approximately 3 to 5 cubic feet per minute (cfm) at a pressure of up to 65 pounds per square inch (psi), although 20-24 psi is more typical. Each sparge point will receive air for 7 to 8 minutes approximately 18 times per day. The cycle timing will be programmed and cycle duration adjusted as needed. The entire unit operates on 110- volt power. A diagram of the C-Sparer unit is enclosed in Appendix B. 5.3 - Manifold System The air/ozone mixture will be pumped through double contained ozone- resistant poly tubing from the C-Sparing System to the sparging wells. Singh's Unocal Remedlid Action Plan — March 2002 _7-