Laserfiche WebLink
From:Harold S.Peters Harold S.Pot..;PE H 91693300/0 To:SO,Hun6N at Stactton Ph6nG Pape 3 o44 Tu,sdW.Mg99.1996 6:1626PM <br /> Stockton Plating <br /> Closure of PBR treatment system <br /> Page 2 <br /> The pipeline area will be visually inspected by Harold Peters. Samples will be taken at any <br /> area that appears may be contaminated. If no area appears contaminated, random samples will <br /> be taken. A minimum of 5 samples will be taken. The samples will be analyzed for copper, <br /> nickel and chromium. A background sample will be taken from south of the end of the pipe. <br /> Sample locations will be indicated by a wooden stake. Photos of the excavation will also be <br /> taken. <br /> Analytical results will be evaluated using the Preliminary Endangerment Assessment process <br /> published by the Department of Toxic Substances Control. If contamination is discovered <br /> either visually or by sampling, the appropriate regulatory agencies including the County of <br /> Stockton and the DTSC will be notified. If the contamination appears to be limited, additional <br /> material will be excavated and packaged for evaluation as hazardous waste. The area will <br /> again be sampled. If contamination appears to be more than superficial, a formal remedial <br /> action plan will be prepared. <br /> Treatment system <br /> The first objective is to remove virtually all of the solids from the treatment system. Each tank <br /> in the treatment system will be pumped to the feed tank for the filter press. Pumping will be <br /> done using existing pumps or the portable mud pump. The three below-grade concrete tanks <br /> will be washed using a fire hose to slurry any solids that have settled to the bottom. The water <br /> from the filter press will be batch accumulated and analyzed prior to discharge. If the water is <br /> not acceptable for discharge to the sewer, it will be treated in the treatment system. This <br /> process will be continued until the equipment and tanks are emptied of solids and the resulting <br /> water from the filter press is acceptable for sewer discharge without treatment. <br /> Concrete tanks <br /> All concrete below-grade tanks will be cleaned using procedures developed after visual <br /> inspection of the concrete below water level. Cleaning will probably be a combination of <br /> chemical methods, water blasting and scrapping. The final cleaning will be by sand blasting <br /> followed by a sodium hypochlorite rinse. Three chip type samples will be taken of each tank. <br /> The chip samples will be taken by drilling a 1h" diameter hole approximately 1" deep in two <br /> walls and the floor. All concrete below-grade tanks will be visually inspected by Harold <br /> Peters for evidence of cracks or other possible routes of exit from the tanks. If a possible leak <br /> is located, plans will be prepared to evaluate the significance of the situation. <br /> If no routes of exit are discovered, the tanks will be placed out of service by installing a liquid <br /> detection system at the low point in each tank. The liquid level detection will have an local <br /> indication of liquid detection. The daily facility checklist will include checking to determine <br /> that the liquid detection system has not detected liquid. <br />