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2012 TIDEWATER STOCKTON WORK PLAN FOR SEPARATE PHASE HYDROCARBON REMOVAL AT THE WATERFRONT TOWERS PARKING LOT ____________________________________________________________________________ 5 3.0 Remedial Action Implementation 3.1 Remedial Design The 10 ft by 14 ft remediation compound that will enclose the proposed product recovery system will be located outside the southwest corner of the Waterfront Towers parking lot entry way, just outside the wrought iron fence as shown in Figure 2. A remedial system design package will be prepared and submitted to City of Stockton for issuance of a building, planning, and a fire permit. Currently, negotiations are on-going for drafting an access agreement between Stantec and WOTOA property owners on terms agreeable to both the interested parties. An air compressor and 247-gallon product recovery holding tank with associated logic controls will be located inside the compound. A 3-2 rotary scroll air compressor with five-horsepower (hp) TEFC motor at 12.5 standard cubic feet per minute flow and 145 pounds per square inch pressure will be connected to the active skimmer. The air compressor will contain various checks and controls, such as check valve, pressure relief valve, pressure gauge, solenoid valve, ball valve, for safe and efficient operation. A secondary contained product tank will have a level indicator and an ultrasonic level transmitter to determine the amount of product collected. Air compressor and holding tank will be connected to a program logic controller based control panel with NEMA 4 lockable panel enclosure. A 2-inch diameter specific gravity based QED SPG2 AutoGenie®skimmer will be installed inside monitoring well MW-50. The skimmer consists of an air powered pumping unit (bladder) with a floating inlet to track changes in water fluctuations. The skimmer contains a float which will minimize water intake by using specific gravity and includes multiple inlet holes to allow fine tuning of the inlet valve depending on the product thickness and changes. The floating inlet is designed to follow the SPH layer as the water level fluctuates for up to 24 inches. The QED skimmer has the capability to remove up to 160 gallons per day of product based on manufacturer’s specifications. Based on historical vacuum extraction events, it is anticipated that the skimmer will run for approximately one hour, cycling at every six hours. However, the run time and skimmer placement will be revised and optimized based on actual recovery conditions achieved during startup and continuous operation of the system. In addition to the active skimmer in MW-50, Stantec proposes to install passive skimmers in MW-43, MW-47, MW-48, and MW-49 which contain minimal product (up to a few inches maximum). Passive skimmers installed in these wells will be emptied into a holding tank manually once every month, in concurrence with the operation and maintenance activities for the skimmer system. The design package that will be prepared and submitted to the City of Stockton for a building permit will include drawings of the proposed product recovery system and its various structural components, anchorage details, process and instrumentation diagram, electrical details, and the location of proposed remediation compound.