Study On The Efficiency Of SBR Process For Simultaneous Removal Of Nitrogen And Phosphorus From Domestic Sewage

The simultaneous nitrogen and phosphorus removal of domestic sewage has always been a problem,and it is also a hot spot in the field of water treatment.The SBR process is a variant of traditional activated sludge.The process integrates biodegradation,biochemical reaction,sedimentation and drainage into one reactor.It belongs to batch operation and realizes simultaneous nitrogen and phosphorus removal by regulating the running time and sequence.This paper takes artificial simulated domestic sewage as the research object,optimizes the operating parameters of SBR reactor,regulates the influencing factors,realizes simultaneous nitrogen and phosphorus removal,simultaneously observes the biological phase,analyzes the microbial structure community,and provides the best for existing sewage treatment plants.The operating parameters and influencing factors provide theoretical basis and technical guidance for the research of nitrogen and phosphorus removal in the field of real domestic sewage treatment.The effects of different HRT and influent organic load on simultaneous nitrogen and phosphorus removal in SBR process were investigated.The results showed that when HRT was added to the carbon source in the 6 h anoxic zone,the effect of nitrogen and phosphorus removal was the best,and its COD,NH₄⁺-N,The removal rates of TN and TP were 93%,99%,98%,and 95%,respectively.When the average COD concentration of influent organic load was 200 mg/L and 300 mg/L,the effect of nitrogen and phosphorus removal was the best.As the organic load of the influent water increases,the effect of nitrogen and phosphorus removal becomes worse.Microorganisms and high-throughput sequencing methods were used to analyze the microbial community structure under different HRT and influent organic load conditions.The results showed that when the HRT was 6 h,the sludge floc structure was compact and the sludge volume index?SVI?is 61 mL/g,the sedimentation performance is good;when the average COD concentration of the influent organic load is 200 mg/L and 300 mg/L,the floc in the sludge becomes larger,the sludge structure is dense,and the sedimentation performance is good.After the large influent organic load,the sludge disintegrated,the floc became smaller,and the sedimentation performance deteriorated.In the two working conditions,Proteobacteria,Bacteroidetes and Candidatus Saccharibacteria were the main samples in each sample.For the bacterial population,the relative abundance was 41.06%,17.49%,and20.3%when HRT was 6 h,and the relative abundance of Proteobacteria reached the maximum,77%with the average organic COD concentration of 300 mg/L.With the increase of organic load,the relative abundance of Proteobacteria is reduced,and the removal effect of organic pollutants is deteriorated.The number of non-functional flora such as Parcubacteria,Laterscibacteria and Armatimonadetes is still very low.At the genus level,the relative abundance of Saccharibacteria genera incertae sedis is obvious in both cases.The average organic COD concentration is 300-500 mg/L,Rhodobacter and Thiothrix were detected.The effects of different pH values and temperature on simultaneous nitrogen and phosphorus removal in SBR process were investigated.The results showed that the pH value had no significant effect on simultaneous nitrogen and phosphorus removal in SBR process.The best removal effect was at 25-30°C,COD?NH₄⁺-N?TN and TP were 93%,99%,97%,95%,respectively.