Ultrafiltration behaviour of extracellular and metabolic products in activated sludge system with UF separation process

Ultrafiltrations were conducted using a stirred batch cell for the batch cu lture supernatants containing extracellular and metabolic products released into culture medium from activated sludge bacteria mixture and Sphaerotilu s natans strains responsible for aerobic bulking of the conventional activa ted sludge process. There existed differences in time-dependent relative pe rmeate flux among growth phases for the same organisms and among the organi sms grown to the same stationary growth phases, respectively. The retained ratio of protein to sugar during filtration may be one of the factors affec ting the magnitude of time-dependent relative permeate Rus decline, suggest ing different degrees of interactive effect of both protein and sugar depen dent on organism species and their growth phases on permeate Aux decline ch aracteristics of culture solutions. (C) 2000 Elsevier Science Ltd. All righ ts reserved.