ARCHIVED REPORTS XR0009904 - Laserfiche WebLink

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Corrective Action Plan Page 27 sample occurrences where the apparent concentration of hydrocarbons in the groundwater ! was much greater than those that have been consistently detected over the past two years Despite that conservatism, the estimated 3 62 ppm concentration of VOCs in the groundwater that will be pumped from the remedial excavation is significantly Iess than the 8 33 ppm contaminant concentration that would cause uncontrolled emissions from the ' system to equal the regulatory limit if the treatment system were to be run continuously, 24 hours per day, at its rated effluent capacity of 45 gpm The conservative analyses presented above demonstrate that emissions to the air from the proposed groundwater treatment system will be well within the limits set by the SJVUAPCD for operation of unregulated facilities However, to ensure that the as-built system will, at all times, comply with the applicable regulations, even under extreme and unlikely operating conditions, provisions have been made to monitor and control any process state in the treatment system that might threaten to produce excessive emissions A pre-defined program for sampling the air emitted from the sparging tank will be 1 established that will permit early detection of any precipitant out-of-bounds condition The treatment system plumbing is designed so that, if any such condition should occur, the sparge tanks can be by-passed and all contaminants dissolved in the groundwater being pumped to the treatment system can be captured in the carbon adsorption units so that no VOCs are emitted to the air until the overload state has passed The arrangement of valves and piping that allows the air stripper to be bypassed is shown schematically on Figure 10 During the first filling of the sparge tanks the air emitted from the tanks while the water is sprayed into them and while the water is being sparged will be sampled and analyzed for total petroleum hydrocarbons using a portable organic vapor meter (OVM) These measurements will be repeated daily when the treatment system is in operation j If the concentrations of VOCs in air rising from the sparge tanks, is within 5% of that which would yield a total emission equal to or grater than the permissible limit of 2 lb per day if the treatment system were operated continuously for 24 hours, emissions to the air will be restricted by temporarily reducing the rate of groundwater pumping or by-passing the sparge tanks until the lugh contaminant-load excursion has passed It is not expected ' that there will be any actual need to implement these contingency measures, but the capability to operate the treatment system in the described manner ensures that emissions to the air will be maintained within permissible limits under any foreseeable condition ' Noise Control ' To comply with City of Tracy Ordinance No 898 C S (Tracy Municipal Code Title 4 Chapter 3, Article 10 Noise Control) all construction machinery used for remediation will be equipped with noise suppression equipment such that noise that is generated by that equipment does not exceed 65 dB at the boundaries of the site and the hours of work on the site will be restricted to those between 7 00 AM and 10 00 PM