Study On Denitrification And Sludge Reduction Effect Of Anoxic/Oxic(A/O)Biological Contact Oxidation Process For Municipal Domestic Wastewater Treatment

The characteristics of urban domestic sewage,as well as the sewage treatment facilities to reduce the amount of sludge,nitrogen removal effect is not significant and easy operation and other aspects of the requirements.In this study,the biological contact oxidation process was improved to make it applicable to denitrification and sludge reduction treatment of urban domestic wastewater.According to the features and technical and economic conditions of urban sewage treatment,an Anoxic/Oxic(A/O)biological contact oxidation reactor was constructed.The sludge in the O pool is returned to the A pool.The returned sludge adsorbs pollutants in the influent water and is then anaerobicly hydrolyzed by the microorganisms so that the sludge is reduced,and the carbon source needed for denitrification is provided.In this paper,the removal efficiency of Anoxic/Oxic(A/O)biological contact oxidation reactor,sludge adsorption performance and microbial characteristics were studied.The treatment effect of Anoxic/Oxic(A/O)biological contact oxidation process on domestic sewage was studied.The results showed that the average concentrations of influent COD,TN,NH4+-N,and SS were 245.6 mg/L,51.9 mg/L,33.5 mg/L,and 116.4 mg/L.Without reflux,the average concentrations of COD,TN,NH4+-N,and SS in the effluent of the A/O biological contact oxidation process were 59.0 mg/L,16.5 mg/L,8.9 mg/L,and 9.4 mg/L;With the addition of aeration reflux,the average concentrations of COD,TN,NH4+-N,and SS in the Anoxic/Oxic(A/O)bio-contact oxidation process were 35.0 mg/L,9.8 mg/L,1.6 mg/L,and 3.5 mg/L.Among them,there is reflux,O pool effluent SS fluctuate up and down 8.1 mg/L,no reflux,O pool fluctuations in 16.2 mg/L,O pool effluent concentration decreased significantly.The microorganisms in the device were analyzed by electron microscopy and high-throughput sequencing to compare the distribution of microbial populations and predominant microflora in the reactor when there was no reflux,resulting in the discovery of a population structure of microbes in the reflux and non-return A and O pools.There is no significant difference in the category,but in the case of dominant bacteria,there is a large proportion of denitrifying bacteria in the A pool,and there is also a small part of the O pool,which is conducive to nitrogen removal.In the absence of reflux,the microbial species of the A and O pools are generally similar,but there are certain differences in the dominant strains,and the relative abundance of non-returned denitrifying bacteria is low.At the same time,the sludge biofilm adsorption and O pool sludge migration of O pool were studied.The removal rates of COD and SS in aerobic unit sludge adsorption tests were 46.01%and 80.19%,respectively.TN and NH4+-N The removal effect is not significant,only 17.00%and 15.05%,the removal rate of TP reaches 53.08%,and the sludge has an adsorption effect on the SS in the sewage,indicating that in a short time,the pollutants in the sewage can be transferred to the active pollution.Mud on.In the sludge tracer test,the 813C value of each sampling point of the A pool was higher than that of the original anoxic tank after the system added the labeled sludge sample,and there was a 13C trace at each sample point,and the return sludge entered into the lack.There is a certain difference between the internal and external contents of the A pool,indicating that the sludge can enter theinterior of the filler during the reflux.In summary,the Anoxic/Oxic(A/O)biological contact oxidation process can enhance the effect of denitrification and sludge reduction of urban domestic wastewater,and it is feasible for the treatment of urban domestic sewage.