Research On Nitrogen And Phosphorus Removal And Transformation Way Of Phosphorus Under Different Mixture Reflux Ratio In The Combination System

This research project uses an integrated combination process,composed of biological flocculation,hydrolysis and acidification and A~2/O three parts.The device is characterized by the use of bio-flocculation flocculation adsorption to remove large particles of pollutants and converted to small molecules of organic matter,and then as an additional carbon source through the metering pump added to the A~2/O of the anoxic tank,to improve the system of nitrogen and phosphorus removal effect.The experiment is under the following conditions: the ambient temperature is about25 ?,the influent flow rate Q = 10L/h,the activated sludge reflux rate is 0.5Q,the sludge reflux ratio is r = 100%,the hydrolytic acidification solution is put into the anoxic tank as an additional carbon source.The concentration of the flocculation tank is between1500 ~ 2500mg/L,the A~2/O pool is controlled between 3.0~3.5g/L,the hydraulic retention time of the anaerobic tank and the anoxic tank is 2h,the Aerobic pool hydraulic retention time is 5h,the use of aeration pump to the aerobic tank aeration,through the flow meter to control DO to 3mg / L or so.The sludge age of A~2/O area is 15 days.By changing the reflux ratio of the mixture,the removal efficiency of COD,ammonia nitrogen,total nitrogen and phosphate was studied under the four conditions(the reflux ratio of the mixture was R = 100%,200%,300% and 400%,respectively).The main results of the experiment are as follows:(1)The average removal rates were 83.07%,84.61%,87.69% and 87.28%,respectively.The removal efficiencies of the mixed solution had little effect on the COD removal efficiency.The average removal rate was 97.42%,98.07%,98.34% and 98.79%,respectively.There was no significant difference in the removal efficiency of ammonia nitrogen.The removal efficiency of total nitrogen was the highest when the reflux ratio of the mixture was 300%,the removal rate was 71.94%.The change of the reflux ratio of the mixture has an indirect effect on the phosphorus removal effect.The removal effect is consistent with the total nitrogen.When the reflux ratio of the mixture is 300%,the removal efficiency of the phosphate is the best,the removal rate is 89.67%.(2)The results showed that the proportion of DPAOs in PAOs was 11.17%,18.99%,26.22% and 20.43% respectively under the four conditions.The results showed that theproportion of PAAOs was 11.17%,18.99%,26.22% and 20.43% respectively under the four operating conditions.It can be seen that the internal reflux ratio R = 300%,the denitrification efficiency is the highest.(3)The results of the transformation of phosphorus in the composite system were as follows: the ratio of TP to effluent discharge was 15.54%,13.48%,11.45% and 11.75%respectively.The percentages of microbial growth and metabolism were 16%,12%11.8%,12.97%,and 12.03%,respectively.The proportion of phosphorus removal was9.8%,11.9% and 12.0%,respectively.The proportion of phosphorus removal by phosphorus was 59.81%,61.46%,61.47% and 59.76% The proportion of absorption was0.4%,1.1%,2.32% and 3.56%.