WORK PLANS FILE 2 - Laserfiche WebLink

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I Following a meeting with the County regarding the residual soil contamination at the site, ` the County has issued a directive to conduct a vapor extraction pilot test. Five vapor r extraction wells ( VW- 1 , VW- 3 , VW- 4, VW- 5 and VW- 6 ) are currently installed and will be used to conduct a soil vapor extraction test to determine if subsurface conditions are currently favorable to soil vapor extraction as a continued remedial option. VAPOR EXTRACTION WORK PLAN - California Geophysical Group, Inc. proposes to conduct a two day soil vapor extraction test to determine if subsurface conditions are still favorable and conducive to continuing soil vapor extraction on the contamination plume at this site. Also this test will determine the feasibility of continuing the soil vapor extraction at a soil remediation option and, if appropriate, to determine design parameters of a new vapor extraction remediation system. Vapor Extraction Pilot Testing and Sampling Initial Testine The purpose of this feasibility testing is to provide order-of-magnitude information on achievable vapor flow rates, vacuum, radius of influence and extracted soil vapor concentrations. This information will also be used to generate a 2006 Feasibility Report with the new data generated from this event. The vapor extraction wells that have been in service in the past and are to be used for this test are: VW- 1 ,3 ,4, 5 & 6 . These vapor wells were installed several years ago and have been idle since 2003 . Within this scope of work is also the determination that all of the conveyance pipe lines between the vapor wells and the treatment compound are still in good working order and can be used to extract vapors from the existing five wells. To begin the first phase of the test we will be connecting VW- 1 to the Internal Combustion Unit ( ICU ) via a flexible or rigid 2" influent pipe. The influent pipe is connected to a rotary positive displacement air pump that is capable of creating 10" of mercury vacuum. During the pumping of the vapor we will utilize an internal combustion engine equipped with a catalytic converter to induce a downhole vacuum for a period of at least two hours. Each of the other extraction wells ( VW- 3 ,4, 5 & 6 ) will be monitored for vacuum influence in the subsurface. The sphere of vacuum influence monitoring will be completed with the use of a Dwyer Digital — Manometer ( Series 477 ). The meters are calibrated in the 0 — 20 in. water column and 0 — 200 in, water column. Temporary well caps will be placed on each of the monitoring points with a brass ball valve installed in the top. The meters will be placed onto the sample port via a 3/16" tubing and the ball valve opened, paying particular attention as to not let any vacuum escape. As each well is monitored the reading will be entered into the field data log.