(658b) Electrocoagulation As a Pretreatment for Reverse Osmosis for Potable Water from Brackish Groundwater

Reverse osmosis (RO) is a widely utilized for desalination. Here we focus on brackish water desalination for production of drinking water. We have explored the use of electrocoagulation as a pretreatment prior to reverse osmosis. Our study examines the application of an electrocoagulation and a RO hybrid system for treating actual brackish groundwater focusing on reducing RO scaling by electrocoagulation pretreatment. Water was obtained from a San Antonio Water System (SAWS) brackish groundwater treatment plant that operates a three stage RO system.

A series of electrocoagulation operating conditions was investigated, such as applied voltage, pH, reaction time, and type of electrode. Optimized batch-electrocoagulation experimental operating conditions (20 V, 5 min reaction time, pH 8 using 3*Fe / 2*Al electrodes) were found, and the removal efficiency of the main foulants, including silica, iron, calcium, and magnesium determined. To assess the scaling potential of the electrocoagulation pretreated feed stream for the SAWS brackish groundwater desalination plant, we utilized the commercial software called WAVE. The electrocoagulation pretreatment method was effective in preventing membrane scaling, as compared to the feed without electrocoagulation. These results suggest that electrocoagulation could be a viable pretreatment method prior to RO.