WORK PLANS - Laserfiche WebLink

Home Browse Search

15 December 2003 AGE-NC Project No. 95-0109 Page 5 of 6 4.2. WELL COMPLETION Three soil borings will be advanced for the installation of ozone injection points. Following advancement of the soil boring,one manufacturer-assembled 2-inch by 30-inch microporous sparge point and casing will be installed in each boring; the sparge points will be installed at depths of approximately 70 feet bsg. A '/a-inch PVC riser will connect the sparge points to a surface ozone generator. A proposed ozone sparge well construction diagram is depicted in Figure 5. After installing the well casing in each boring,a filter pack material will be slowly emplaced through the augers over the screen interval to approximately two feet above the screened intervals for the monitoring well. The filter pack material in the ground water monitoring wells will consist of pre- washed#3 Lonestar sand. Following placement of the filter pack, the screened interval from each well will be surged for approximately 20 minutes utilizing a surge block to assist in settling the filter pack. Additional filter pack material will be added if settling occurs. A nominal 2-foot bentonite seal (bentonite chips)will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the well. The bentonite seal will be formed by pouring bentonite chips into the annulus and allowing the pellets to settle on the filter pack.The bentonite pellets will be allowed to hydrate with tap water for a minimum of one-half hour prior to grouting. The filter pack material in the sparge points will consist of a#2/16 sand.After installing the lower sparge point casing in boring, the filter pack material will be slowly emplaced through the augers or tremie pipe over the screen interval to the top of the sparge point.A bentonite seal will be formed by pouring bentonite pellets into the annulus, to a depth of 25 feet bsg. The upper sparge point casing will be placed into the boring, and a second filter pack material will be slowly emplaced to the top of the upper sparge point.An upper bentonite seal will be formed by pouring bentonite chips into the annulus and allowed to hydrate with tap water for a minimum of one-half hour prior to grouting. The remaining annular space will be filled to the ground surface with a cement grout. The grout mixture will consist of Type I/II portland neat cement and not more than 6 gallons of water per 94-pound sack of cement. The grout will be placed by pumping through tremmie pipe. A grouting inspection will be scheduled with EHD personnel. 4.3. IN-SITU OZONE SPARGING PILOT STUDY The typical ozone system is an in-situ air stripping process utilizing fine bubbles of ozone-rich air, injected into saturated soil to extract and decompose dissolved petroleum hydrocarbon constituents. Advanced GeoEmvironmental,Inc.