Study On Treatment Of Wastewater By Side Chemical Phosphorus Removal-SBR In Townlets

A new method of nitrogen (N) and phosphorus (P) removal was proposed, side chemical phosphorus removal-SBR (SCPR-SBR). A systematic research was made on the new method and the process Side chemical phosphorus removal-SBR which based on the new method. Detailed work corresponding included that:research on removal ability of N and P by orthogonal and theoretic experiment in SCPR-SBR system; Experimental research on main factors such as operation behaviors, C/N, DO (dissolved oxygen), the ratio of P removal by bypass. Accordingly, the main conclusions were as follows:1) The Side chemical phosphorus removal-SBR was studied. It was discovered that the process could have the the function of P removal by side chemical phosphorus and simultaneous nitrification and denitrification(SND),successfully solved the conflict of controlling sludge age of nitrogen and phosphorus, accomplished the aim of C,N and P removal; the process saved the dosage of the phosphorus removing agent, when the molar ratio of Aluminum to phosphorus equaled to 1.5, removal percentage of TP come to a climax of 95.71%.The system had a good stability, satisfied steadily the Class A of Integrated Wastewater Discharge Standard.2) The operating conditions of SCPR-SBR process were investigated.â‘ The effect of different operating conditions on the process performance was investigated. It was discovered that the sequence of influence extent from serious level to light level was the molar ratio of Aluminum and phosphorus, pH, coagulation time, settling time and rotation rate.Among these factors, the molar ratio of Aluminum and phosphorus was the remarkable factor, pH took the second place. Although coagulation time, settling time and rotation ratedont had remarkable influence, appropriate waterpower and settling time were the necessary conditions to obtain high TP removal rate.â‘¡The effect of different DO on the process performance was investigated. It was discovered that:Different DO was demanded by heterotrophic bacteria, nitrobacteria and phosphorus accumulating organisms, which was the important element to obtain the excellent P and N removal. Among the range of experiment, when DO was curbed to 3.0-4.0mg/L,the rate of nitrification and denitrification was approximate,the more approximat was, the bertter TN removal was.â‘¢The effect of carbon to nitrogen (C/N) molar ratio on the process performance was investigated. It was discovered that in the test condition,the change of C/N almost had no effect on TP,NH3-N and COD removal,but had remarkable effect on TN removal.The process at the molar C/N ratio of between 6:1 and 8:1 obtained good effects,which was the SND process,and the ratio was similar with townlet wastewater.â‘£The effect of side chemical phosphorus removal rate on the process performance was investigated. It was discovered that rate of side chemical phosphorus removal concerned the dosage of the phosphorus removing agent and the balance of effluent water quality, the best rate could help instruct engineering practice. In trail condition, when the rate was above 40%, the average P removal was above 90%, TP could satisfy the standard of effluent.