Application of CASS in Treating Domestic Sewage at Low Temperatures

The feasibility of using CASS technique for treating domestic sewage at low temperatures was investigated. The results indicate that for domestic sewage (averagely, ρ(BOD5)=295.7 mg/L; ρ(CODCr )= 811.7 mg/L; ρ(SS)= 119.6 mg/L), the removal rates are 95.3%, 85.7%, 91%, respectively. The CASS technique is operable in a wide range of temperature (about -5～20 ℃), but φ(S) and ρ(S) values are higher at low temperature than those at normal temperature. A low temperature is good for oxygen transmission and the cyclic fluctuation of DO (dissolved oxygen) is benefit for the removal of P and N, preventing the sludge from bulking.