| The Truckee Meadows Water Authority (TMWA) is the main water purveyor to the greater Reno-Sparks area. TMWA operates two conventional surface water treatment facilities and 30 groundwater wells. To meet the challenges of the new arsenic maximum contaminant level six wells were selected for blending and treatment at one of the existing surface water treatment plants. This necessitated an evaluation of the chemical treatment scheme to ensure adequate arsenic removal under all operation conditions.; Most arsenic treatment facilities utilize ferric chloride in a direct filtration or in-line filtration process. Truckee river water is best treated with polyaluminum chloride (PACl), but PACl alone does not provide effective arsenic removal at reasonable doses. Because surface water treatment will remain the goal of the Glendale facility 97% of the time, PACl was retained as the primary coagulant, with the addition of 1-2 mg/L of ferric chloride as required for arsenic removal. |
