Study On The Pollutants Treatment Characteristics At Different C/N And Salinity In Atmosphere-Exposed Biofilm

With the development of economy and society,water resources shortage and water pollution problems were becoming increasingly serious in China.However,in the actual process of wastewater treatment,the fluctuation of influent load was more in majority of the wastewater treatment plant,such as the C/N load,causing a great impact on the treatment effect of wastewater treatment plant.In addition,the discharge of high salt wastewater was increasingly,the effect of salinity on the wastewater treatment system can not be ignored.Therefore,Atmosphere-Exposed Biofilm system with convenient management,and low operation cost was used in this paper,C/N and salinity as variables,the effects of different C/N and salinity on treatment characteristics of organic matter,nitrogen,phosphorus and other pollutants in Atmosphere-Exposed Biofilm system were investigated.The treatment performances of Atmosphere-Exposed Biofilm system were explored in this study to provide the basis for the popularization and application of Atmosphere-Exposed Biofilm system.The results as follows:1)In Atmosphere-Exposed Biofilm system,with the increase of C/N,the average removal rate of COD increased,when the C/N was 100,the effluent concentration was lowest,and the removal rate was highest.In low C/N conditions,with the increase of C/N,in the conditions of C/N was 10,15 compared to C/N was 5,the removal rate of COD was significantly improved(P<0.05).In high C/N(50,75,100)range,the removal rate of COD was no significant difference(P>0.05),the system was relatively stable.However,compared with the low C/N(5,10,15),the removal rate of COD was significantly increased(P<0.05).In terms of the effcets of C/N on average removal rate of COD,the maximum removal rate of COD was observed when C/N was 50.2)In Atmosphere-Exposed Biofilm system,with the increase of C/N,the average removal rate of ammonia was decreased and then increased and then decreased,the highest removal rate was observed when the C/N was five.Compared with C/N was 10 and 15 conditions,the average removal rate of ammonia decreased significantly(P<0.05).There was no significant change in the high C/N range(P>0.05),and the removal rate(P<0.05)was significantly lower than that of the other three C/N conditions.At the same time,with the increase of C/N,the removal rate of ammonia by systems gradually decreased,the removal rate of ammonia was the fastest was observed when C/N was 5.3)In Atmosphere-Exposed Biofilm system,with the increase of C/N,the average removal rate of TN increased and then decreased.In low range of C/N,the removal rate of TN showed a significant increasing trend(P<0.05),but in high range of C/N,the removal rate of TN had no significant change(P>0.05),the system was relatively stable.At the same time,with the increase of C/N,the removal rate of TN by systems decreased gradually,in high C/N conditions,the removal rate of TN was relatively stable,and the change was small.4)In Atmosphere-Exposed Biofilm system,with the increase of C/N,the average removal rate of TP increased and then decreased.In low range of C/N,the removal rate of TP was significantly increased(P<0.05),but in high range of C/N,the removal rate of TP had no significant change(P>0.05).Compared to the other three low C/N,the removal rate increased significantly(P<0.05).With the increase of C/N,the removal rate of TP increased and then decreased,the maximum removal rate of TP was observed when C/N was 75.5)The different C/N and influent and effluent concentrations of COD,ammonia,TN,and TP(Se/So)were used to nonlinear fitting,and nonlinear fitting degree about C/N and influent and effluent concentrations COD,ammonia,TN and TP(Se/So)had a certain correlation.In addition,the fitting equation was tested using the chi square test(χ2),and the fitting equation can be used to predict the treatment effect of the system.6)Under the conditions of C/N was 10 and three different salinities(6‰ 2.5%,5%),with the increase of salinity,the removal rate of COD,ammonia,TN and TP decreased,the salinity had a certain inhibitory effect on heterotrophic microorganisms and biological nitrogen and phosphorus removal.With the increase of salinity,the removal rate of COD and TN decreased more evenly,while for ammonia and TP,the effects of high salinity on the removal rate of ammonia and TP was greater than that of low salinity.In addition,compared with the removal rate of ammonia,TN and TP,the inhibitory effect of salinity on denitrifying bacteria was greater than that of nitrifying bacteria,the inhibitory effect on the phosphorus accumulating bacteria was greater than that of nitrifying and denitrifying bacteria.7)Under the conditions of C/N was 100 and three different salinities(4‰,2.5%,5%),with the increase of salinity,the removal rate of COD,ammonia and TP decreased.And under the high and low salinity conditions,and the effects of C/N on treatment efficiency of system were compared and analyzed.Compared with the high salinity,the influence of C/N on COD and TN removal effect of the system was relatively significant in low salinity conditions;and the influence on the removal of ammonia was relatively small;In addition,in low and high salinity conditions,C/N on the removal efficiency of TP had no significant effect.