AWWA WQTC65758

This paper discusses the various treatment and disposal alternatives for phosphoric acid clean-in-place (CIP) waste from microfiltration/ultrafiltration (MF/UF) utilities. The waste streams generated in MF/UF membrane systems are a concern to utilities that do not have available options for disposal. Typical waste streams from MF/UF utilities include spent backwash (BW), maintenance wash (MW) and CIP waste streams. Since some water utilities do not have access to a sewer line or are not near a wastewater facility, their only disposal option is recycling or further treatment of these waste streams. Treatment and subsequent recycle of waste streams generated by membrane filtration processes requires coordination between the regulatory agency, the utility, and the design engineers. Equally important, potential impacts on primary treatment process must be considered if recycling of waste is selected. The CIP waste stream is generally the most problematic if disposal is unavailable, because of the high concentration chemical stream. This paper discusses the nature of phosphoric acid CIP waste, while considering volume and impacts of the treatment followed by recycling within the water treatment plant (WTP) or disposal. In addition, an evaluation of experimental treatment and recycle of treated phosphoric acid CIP waste is discussed. Includes reference, figure.