ARCHIVED REPORTS XR0012563 - Laserfiche WebLink

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MAN, WR g FINAL.REMEDIATION PLAN Shell oil Company 020 West Charter Way,Stockton,Califomiz Delta Project No.40-88-586 3 Page 19 Miiii,manwints of regulatory access to system for inspection. I's J o ,,.Just have regulatory-approved monitoring and sampling schedule. % 0.'Systeamust.be well Maintizina. The pump test performed at this site indicates that the TPH di:;charge concentration(average=20 ppm) would meet the <100 ppm requirement without using any pretreatment. The average TTO discharge concentration(7.54 mgA)determined during the pump test is above the required 4.57 mg/I limiting value. U*-nImdr.1zm.plazmcd flow raw is 24 gpm for the entire pumping syg ,& The number of pounds of TTO that would be discharged would be approximately 0.2 lbs/day (see Appendix G for WO discharge calculations). Even though the mass flow irate of the TTOs would be small, the City requires that the concentrations ofTTOs be below 4.57 mg/l prior to discharge to the sarikary sewer system. This means that Taking the above information into consideration,three ground water treatment alternatives were screened: • Activated carbon Packed column air stripping Aboveground biotreatment #tivated,Mftz JS the mo6(cffe4tWmea'M Ofieducing the dissolved hydrocarbons in discharge water from the ground water recovery system to nondetectable limits,and will be used to treat ground water prior to discharge to the sewer. Packed column air stripping is another effective means of stripping volatile organics from the ground water discharge. These units require high maintenance,have a tendency to clog,and are not economical for the small reduction in hydrocarbon concentrations necessary at the site to meet the discharge requirements. Aboveground biological treatment of ground water is relatively costly and would not be practical at this site.