AWWA MTC64569

Electrodialysis reversal (EDR) was pilot tested on moderate total dissolved solids (TDS), high silica groundwater with elevated levels of fluoride and arsenic at Fort Irwin, California. During 75 days of continuous testing, results demonstrated that with minimal pretreatment, EDR was capable of producing water that consistently met the Fort Irwin water quality goals and State of California water quality requirements. The pilot unit was optimized to maximize feedwater recovery while staying within safe operating parameters relative to applied voltage and sparingly soluble salt supersaturation. A scale inhibitor and hydrochloric acid were added at low doses to the concentrate recycle loop to enhance recovery. Activated Alumina, regenerable, (AAR) was also tested at Fort Irwin. Results indicated that this technology was capable of removing arsenic and fluoride; however, the process was heavily impacted by high concentrations of silica in the Fort Irwin source water. This article presents the results of AAR and EDR pilot testing, which was performed to help select and design a full-scale facility for the Fort Irwin new 6-million-gallon-per-day (mgd) water treatment plant. Includes 3 references, tables, figures.