Experimental Study On Nitrogen And Phosphorus Removal In KDCAS System

This thesis summarizes the theories and processes of nitrogen and phosphorus removal, studies the removal of nitrogen and phosphorus in new bioreactor——KDCAS reactor. The KDCAS is a integrated bioreactor developed from UNITANK process which has imperfect phosphorus removal efficiency and low volume efficiency.Based on the treatment effect for municipal wastewater in KDCAS reactor, the transformation rules of nitrogen and phosphorus in a period are researched, the influence of some factors toward the nitrogen and phosphorus removal are discussed, and the flow pattern is analyzed. The experiment results show that:(1) The KDCAS reactor has high efficiency to remove organic matter and NH3-N and has strong bearing capability against impact load. The TN and TP of the output water reached the class I(B) of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant ( GB18918-2002) , but the treatment effect is not perfect.(2) The transformation rules of nitrogen and phosphorus in a period indicate that the phenomenon of simultaneous nitrification and denitrification and denitrifying dephosphatation could exist in the reactor which need further experimental confirming.The removal nitrogen and phosphorus was affected by the setting of stages in a period, ratio of available aerobic time to available anoxic time, carbon source, the value and distribution evenness of MLSS, in which the setting of stages, C/N and the value of MLSS showed a considerably effect on nitrogen removal efficiency, and ratio of available aerobic time to available anoxic time, C/P and distribution evenness of MLSS have obvious influence on phosphorus removal efficiency.(3) The KDCAS reactor is a new-style bioreactor with high efficiency. It has fine flow pattern which is influenced by influent flow rate, hydraulic retention time and the connecting manner of each pool. The type of flow lies between ideal plug-flow and completely mixed model, and it's propitious to improve the removal efficiency of nitrogen and phosphorus.