Study on Biological Phosphorus Removal with A-A/O Process in Guilin Fourth Sewage Treatment Plant

The anaerobic anoxic oxic (A A/O) process was utilized to study the principle of biological phosphorus removal.The results were as follows:the phosphorus removal was significantly inhibited by nitrate salt when its concentration was larger than 5mg/L;the phosphorus release increased linearly when the biological anaerobic phosphorus release time was set between 4～8 hours;the rate of phosphorus accumulation was rapid when the aeration phosphorus accumulation time was set between 1～3 hours It was also found that the maximum phosphorus accumulation occurred after 5 hour anaerobiosis followed by 2 hour aeration when the maximum capacity of unit sludge amounts to 3.35×10 -6 and the rate of oxygen comsumption then was 0.163mg/Lmin.