Pretreatment Condition in the Full Scale Dissolved Air Flotation Process Using a DAF Pump

ABSTRACT : Dissolved air flotation (DAF) process is generally considered more effective than sedimentation process in raw water containing algae, humus materials, and low density particles. This study presents the treatment efficiencies by the coagulation and floccu-lation conditions at a drinking water treatment plant using a laboratory tester and the full scale DAF pump system. The full scale DAFpump system (F-DAF) in this study had a capacity of 5,000 m 3 /d and a hydraulic surface loading of 10 m/hr. F-DAF in D drinking watertreatment plant was continuously operated to determine the operational performance and pretreatment (mixing and coagulation) conditions.Results in the laboratory experiment showed that the optimum coagulant (PSO-M) doses required to 2.7q4.5 mL/m 3 /NTU with raw waterturbidity from 13.8 NTU to 56.3 NTU. F-DAF in the optimum coagulant dosage could be operated in effluent turbidity of 1 NTU or below for a month. Key Words : DAF, Flotation, Full Scale, Coagulation, Flocculation, Drinking Water