UPGRADING OF A BIOLOGICAL-CHEMICAL TREATMENT-PLANT FOR CHEESE FACTORYWASTE-WATER

A biological-chemical treatment plant for cheese factory wastewater wa s upgraded to handle increased loads and achieve higher removal effici encies with respect to organic matter and phosphorus. An existing aera tion basin was converted to an aerated equalization tank and two exist ing trickling filters were replaced by two moving bed biofilm reactors (MBBRs). In the MBBRs biomass is attached to small plastic elements t hat move freely along with the water in the reactors. A new final sett ling tank was added after an existing intermediate settling tank and e xisting flocculation chambers. At loads that were highly variable and often above the design values, the upgraded plant achieved average rem oval efficiencies of 98% with respect to both total COD and total P. A n average effluent concentration of 0.36 mg total P/I was obtained wit h an average coagulant dose of 2.0 mol Al3+/mol P. Copyright (C) 1996 IAWQ. Published by Elsevier Science Ltd.