WHAT FLAVOR IS YOUR SODA? IMPROVING WATER QUALITY AND REDUCING OPERATING COSTS THROUGH CONVERSION FROM LIME SODA ASH TO CAUSTIC SODA TREATMENT AT A WATER RECYCLING PLANT

摘要

This paper presents an evaluation of caustic soda as a viable chemical treatmentrnalternative in the removal of nutrients of concern in a water recycling application forrnrefinery cooling tower use. East Bay Municipal Utility District抯 (EBMUD) NorthrnRichmond Water Reclamation Plant (NRWRP) produces a tertiary recycled water forrnuse at the Chevron U.S.A Richmond Refinery. After achieving routine recycled waterrndeliveries, the Chevron Refinery began to see an increase in toxicity level indicatorsrnand cooling system scaling and corrosion levels within the refinery, and suspectedrnthat the chemical treatment of recycled water was a leading factor. Other the next ninernmonths, a study team conducted water process modeling, bench-scale, pilot coolingrntower and full-scale testing to identify the problem and develop a revised program. Thernresults of a successful pilot test and full-scale conversion from a lime soda ash waterrnsoftening technology to a caustic soda and polymer treatment system are discussed,rnas well as the improved recycled water quality and reduction in chemical and solidsrnhandling costs.