Chemically Enhanced Wastewater Treatment: An Appropriate Technology for the 1990’s

Recent experience with chemical enhancement in primary sedimentation shows that marked improvement both in primary removal efficiency and plant flow capacity can be achieved without creating excessive sludge quantity or processing problems. The small amounts of metal salts and polymers added as coagulants and flocculants are effective in treatment plant upgrading. Chemically enhanced primary treatment can be a stand-alone, single-stage treatment process. Alternatively, it can be part of a two-stage process in which a small biological treatment unit is designed to take advantage of the high solids and BOD removal capability of the chemical primary stage.