| Treatment of rural sewage was a key task of the rural human settlement environment improvement action plan.However,under the influence of unique economic,geographical,and climatic characteristics,most wastewater treatment processes were difficult to use directly due to their own limitations in scattered rural areas.Urban sewage treatment plants cannot be compressed directly for use in rural areas.Therefore,it was necessary to choose a suitable treatment process for solving the problem of rural water environment treatment.In this study,an anaerobic baffle reactor(ABR)and a biological trickling filter were coupled,and an ABR-biological trickling filter integrated device was designed and manufactured for decentralized rural domestic sewage treatment.In this experiment,in order to maximize the efficiency of the integrated device in the treatment of rural sewage,the pollutant change laws during the startup of the integrated device were studied.The effects of different hydraulic loads,COD volume loads,tailwater return position and reflux ratio on the removal of pollutants by the integrated device were explored.The ABR reactor,biological trickling filter,and ABR-biological trickling filter integrated device were compared to remove pollutants.The analytic hierarchy process(AHP)was used to optimize the three processes.Research indicates:(1)The startup process of the ABR-biological trickling filter integrated device took a total of 60 days.During the startup process,the p H value of each compartment of the ABR reactor changed as follows: water inlet> water outlet> third compartment> second compartment> first compartment.With the extension of the startup time,the removal effect of the integrated device on COD and ammonia nitrogen gradually improves.Before the end of startup,the removal rate of COD was stable above 80%,and the removal rate of ammonia nitrogen was stable above 75%.The biological trickling filter has a good membrane,and a large number of protozoa were found during microscopic examination.(2)The study found that the hydraulic load was negatively correlated with the removal rate of COD,ammonia nitrogen,TN and TP.The treatment effect was the best when the hydraulic load was 1.75 m3/(m2·d).The removal rate of pollutants by the integration device increases with the increase of the COD volume load.The COD,ammonia nitrogen,TN and TP removal rate of the integrated device is the highest under the condition of the COD volume load of 0.65 kg COD/(m3·d).The removal rate of pollutants by the integrated device showed a trend of increasing first and then decreasing with the increase of the reflux ratio.The pollutant removal rate was the highest when the tailwater reflux ratio was 200%,and the tail water return to the fourth compartment of the ABR can remove pollutants better than return to the top of the biological trickling filter.(3)During the stable operation of the integrated device,it was found that the concentrations of COD,ammonia nitrogen,TN and TP all decreased along the course.The COD and ammonia nitrogen concentrations in the effluent of the device were 40.49 mg/L and 4.08 mg/L,respectively,which met Chinese sewage discharge standard GB18918-Grade A.However,the nitrogen and phosphorus removal effect were general.The TN and TP concentrations of the effluent were 20.78mg/L and 0.95mg/L,respectively,and the effluent TP concentration met Chinese sewage discharge standard GB18918-Grade B.COD had a good removal rate in the ABR reactor and the biological trickling filter,and ammonia nitrogen,TN and TP were removed more in the biological trickling filter and less in ABR.(4)Study on the comparison of treatment effects of ABR reactor,biological trickling filter and ABR-biological trickling filter integrated device,it was found that the removal rate of COD,ammonia nitrogen,TN and TP by the ABR-biological trickling filter integrated device was better than that of the ABR reactor or the biological trickle filter.(5)Study on Optimal Decision of ABR Reactor,Biological Titration Filter and ABR-Biological Titration Filter Integrated Device with AHP,it was found that the comprehensive index evaluation value: ABR-biological trickling filter integrated device> ABR reactor> biological trickling filter,which indicates that the ABRbiological trickling filter integrated device was most suitable for treating rural domestic sewage. |
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