AWWA MTC69783

The City of Yuma, Arizona Agua Viva Water Treatment Facility (WTF) will utilize membrane filtration and is scheduled to be operational February of 2009. The Used Water Recovery System (UWRS) and Chemical Neutralization System (CNS) at the WTF will recover used water, dewater solids, and neutralize spent membrane chemical cleaning wastes. Key components of the UWRS and CNS include the following: the design of the UWRS resulted in a process treatment train of flow equalization (circular concrete basin), chemical addition (coagulant aid/dewatering polymers), clarification (dissolved air flotation), and solids dewatering (solar drying beds), and the recovered water will be returned to the head of the plant while the dewatered residuals will be disposed of offsite; the used water entering the UWRS will consist of backwash from the self-cleaning strainers, "deconcentration" flows from the membrane basins, process basin drainage/overflows, and decant from the solar drying beds; the unique unit process in the UWRS is the use of dissolved air flotation (DAF) for the clarification process; the CNS consists of two rectangular concrete tanks, drain/recirculation pumps and sodium hydroxide/sodium bisulfite chemical feed systems; and, the dual tank design in the CNS will allow the operator to neutralize two different batches/types of spent membrane chemical cleaning wastes. Includes tables, figures.