CUPA Compliance Engineering, Alcoa Fastening Systems, Fullerton, California

In 2014, Stratus Environmental, Inc. (Stratus) was retained to conduct several engineering tasks relating to a 5-year CUPA re-certification at the Alcoa Fastening Systems facility in Fullerton California. A previous CUPA review identified structural issues with several tanks integrated into an on-site hazardous waste treatment plant. The tanks were slated for removal and replacement, but structural anchoring had not been determined. Stratus worked with the tank supplier and redesigned the proposed tanks and conducted a seismic/structural anchoring scenario for the replacement tanks. During this process, and the planning for the tank replacements, the work team determined that the timing required to replace the tanks exceeded the allowable down time for the ongoing processes and production that the Alcoa Facility. Stratus’ work scope was expanded to encompass the design of a parallel hazardous waste treatment system to allow for ongoing Alcoa operations during the proposed construction. The system was designed to process between 20,000 to 40,000 gallons per day of primarily hexavalent chromium waste blended with other dilute process waste. The diverted treatment scenario utilizes sulfuric acid to lower the pH to 2.0 to 2.5 and sodium bilsulfite to reduce the ORP value by 50 mV and once the chrome reduction was complete, the process flow pH was then raised to 8.5 to 8.8 to better facilitate the removal of the trivalent chrome.