Laserfiche WebLink
0 0 <br />Groundwater Monitoring Well Installation <br />Three groundwater monitoring wells (MW -5, MW -6 and MW -7) will be installed in the northeast <br />portion of the facility to monitor the progress and effectiveness of the remedy. The wells will be <br />constructed using 2 -inch diameter, schedule 40 PVC screen and casing to a total depth of about 20 feet. <br />The wells will be screened from a depth of about 5 to 20 feet. A detailed description of groundwater <br />monitoring well installation, development and sampling procedures are contained in Appendix A. The <br />three proposed wells and existing wells MW -I and MW -2 will be monitored monthly for depth to <br />groundwater, dissolved oxygen, carbon dioxide redox potential, temperature and pH. In addition, wells <br />MW -2, MW -5, MW -6 and MW -7 will be sampled monthly for TPH-G and BTEX compounds by EPA <br />method 5030/8015/8020, and for TPH-K, TPH-D, and TPH-MO by EPA method 3510/8015M. <br />Vadose Zone Monitoring <br />An oxygen soil probe manufactured by Datawrite Research Co. will be installed in a borehole located <br />near the former sump at a depth of about 6 to 7 feet. The concentration of oxygen will be recorded on a <br />data logger every 4 hours and downloaded monthly. <br />Soil samples will be collected from the vadose zone near the former sump area on a monthly basis for the <br />first three months and quarterly, thereafter. The samples will be collected from a point about 5 ft from a <br />vadose zone ORC injection point at depths of 7 and 15 feet. The soil samples will be analyzed for <br />TPH-G and BTEX compounds by EPA method 5030/8015/8020; TPH-K, TPH-D, and TPH-MO by EPA <br />method 3510/8015M, and redox potential. <br />A detailed description of the field sampling methods and quality control/quality assurance protocol for <br />this study is included in the field Investigation Methods provided in Appendix A. Health and safety <br />protocol for this project are presented in Appendix B. <br />DATA ANALYSIS AND REPORTING <br />A summary report will be prepared detailing the findings of this demonstration study. The report will <br />include all field and laboratory analytical results, well construction details, and a discussion of the <br />effectiveness of the ORC at supplying oxygen to the subsurface and promoting biodegradation of the <br />petroleum hydrocarbons that are present at the site. <br />SCHEDULE <br />ORC injection and well installation will proceed when PG&E receives regulatory approval of this <br />workplan and obtains appropriate drilling permits. The field work is presently scheduled to begin during <br />11 <br />402_331-98_63 4-4 <br />