Abstract: An experimental study on anaerobic phosphorus release, aerobic phosphorus uptake and denitrifying phosphorus removal by activated sludge from three municipal wastewater treatment plants usingdifferent processes was carried out to determine the denitrifying phosphorus removal ability and comparethe performances. The processes included the Carrousel system with anoxic-oxic stage ( A/O) and thecyclic activated sludge technology ( CAST). The results show that the efficiency of aerobic and denitrifying phosphorus accumulation in CAST process is 3. 34 mgP/h and 2. 23 mgP/h, respectively. The effi.ciency of aerobic and denitrifying phosphorus accumulation in A/0 process is 2. 54 mgP/h and 0. 83mgP/h. The proportion of denitrifying phosphorus accumulating bacteria and aerobic phosphorus accumu-lating bacteria in CAST and A/0 processes were 66. 8% and 24.9%  respectively. The denitrifyingphosphorus accumulating capacity of CAST process was better than that of A/0 process.

Key words: process configuration, denitrifying phosphorus accumulating bacteria, enitrifying phosphorusremoval