Combined with the operating experience of wastewater treatment plants in Kunming, this paper analyzes and compares the precision of traditional calculating method, sludge retention time method and mathematical models in surplus sludge volume calculation of BPNR.

Effect of SRT on Minimization of Excess Activated Sludge Production;

Effect of Carbon Source and SRT on Denitrifying Phosphorus Removal;

The results show that extending sludge retention time(SRT) can improve the capability of anaerobic phosphorous release,while total phosphorous removal rate is not influenced by SRT.

The results indicate that the contribution of anoxic denitrifying phosphorus removal to total phosphorus removal becomes larger with prolonging the sludge retention time.

The difference in denitrifying phosphorus removal performance between biofilm process and activated sludge process was analyzed in aspects of biomass,sludge retention time and mass ratio of carbon,nitrogen and phosphorus.

Based on the concept of sludge retention time(SRT),the difference between general SRT and aerobic SRT is pointed out in this paper and it shows that the SRT of each reaction phase,such as anaerobic,anoxic and aerobic one,are more important than general SRT in biological phosphorus and nitrogen removal system(BPNRS).

Assurance of sludge age improvement DAT-IAT for municipal wastewater treatment;

Effect of sludge age and pH value on simultaneous nitrification and denitrification(SND);

It summarizes the factors influencing the results of the biological phosphorus removal with SBR technique,which mainly includes dissolved oxygen,sludge age and pH etc.