REGIMES FOR ZONE SETTLING OF WASTE ACTIVATED SLUDGES

Regimes for the zone settling of the waste activated sludges has been investigated experimentally. Channelling in sludge was observed in the high concentration test which enhanced the settling. In low concentra tion tests, large flee aggregates would form spontaneously from an ori ginally macroscopically homogeneous settling sludge, which also enhanc ed the settling. Only in the intermediate concentration range could th e Richardson-Zaki type correlation be adequately applied. Empirical cr iteria for differentiation of settling regimes were proposed. Copyrigh t (C) 1996 Elsevier Science Ltd