The reduction of pH with acid is commonly used to prevent inorganic salts from scaling RO membranes. Because there is not yet available a proven anti-scalant to effectively inhibit calcium phosphate scaling, West basin doses sulfuric acid to a pH of 6.3 before the RO membranes. Rising costs of acid have led to the need for an optimization of acid u...

This presentation provides an overview of pre-treatment strategies for the West Basin Municipal Water District. At this district, recycling/reuse of secondary effluent has been taking place since 1995. The typical pre-treatment processes are described and a list of process challenges and regulatory constraints are presented....