ULTRAFILTRATION AS AN ADVANCED TERTIARY-TREATMENT PROCESS FOR MUNICIPAL WASTE-WATER

Treatment of secondary and tertiary municipal wastewater by membrane f iltration has been investigated at the University of California, Davis , California, USA, as described in the following paper. Secondary and tertiary wastewater used during this investigation were produced from activated sludge and media filtration processes, respectively. Ultrafi ltration, hollow-fiber, polysulfone membranes were used in this invest igation for the treatment of secondary and tertiary municipal wastewat er. Membrane operating parameters investigated were cross-flow velocit y, with circulation and single pass flow, trans-membrane pressure and backflushing methods. Total solids and particle size distribution of s econdary and tertiary wastewater were analyzed and correlated with obs erved membrane performance. Reduction of total solids, biological oxyg en demand (BOD), and chemical oxygen demand (COD) of secondary wastewa ter was also determined after treatment with membrane and media filtra tion processes.