Powdered Carbon Enhanced Carbon Capture And Denitrification Reactor Treatment Research On Domestic Sewage

In order to further improve the removal of organic matter and nitrogen and the recovery of organic resources from domestic sewage with low C/N ratio,this study designed an integrated water treatment reactor for denitrification based on pre-carbon capture to capture organic carbon in the front-end to the greatest extent.And denitrification is carried out in the subsequent reactor.In order to further improve the effluent quality of the reactor,powdered activated carbon(PAC)was added to the reactor after one month of operation.In this experiment,two groups of carbon capture and denitrification integrated water treatment reactors with the same specifications were constructed,namely the experimental group(Dosing PAC,denoted as PAC group)and the control group(Control,denoted as C group).During the operation of the reactor,PAC was continuously added to the experimental group,and the control group was not added.It’s aimed to explore the treatment efficiency of this system on actual domestic sewage and the effect of PAC on the system’s treatment efficiency of actual domestic sewage.Also,the effect of PAC on the properties of activated sludge in the system and the influence on the community structure of activated sludge was also explored.(1)The results of water quality testing show that the carbon capture and denitrification integrated water treatment reactor has a good effect on the treatment of various pollutants in domestic sewage.The removal rates of COD,ammonia nitrogen,TN and TP in the control group were 74.56±11.89%,53.21±7.65%,42.04±6.37% and51.42±21.73% respectively;the removal rates of COD,ammonia nitrogen,TN and TP in the experimental group were respectively were 76.32±9.31,55.20±6.75%,41.77±6.20%,73.48±12.50%.The removal rate of COD,ammonia nitrogen and TP in the reactor of the experimental group(PAC)was 1.76±2.58%,1.99±0.9%,22.06±9.23% higher than that of the control group.In addition,PAC has a certain positive effect on the removal of various pollutants in the reactor,among which the removal capacity of COD in the carbon capture section is improved,and the effect on the removal of nitrogen in the denitrification section is small.(2)PAC had a positive effect on sludge performance in the decarbonization stage,however,it had no significant effect on its microbial community structure.Among them,PAC can improve the sludge settling performance to a certain extent,and has a positive effect on the accumulation of biomass in the reactor,but has no effect on the sludge activity.The addition of PAC led to lower EPS secretion,and the content of PN in its main components decreased,but the content of PS did not change significantly.With the stable operation of the decarbonization stage reactor,the microbial community of the decarbonized sludge changed,however,there was no significant difference in the microbial community composition between the control group(A-C)and the experimental group(A-PAC)during the same period.PAC had no significant effect on the community composition of decarbonized sludge at the phylum and family levels,but enhanced the functional bacteria genera associated with COD degradation,such as Acinetobacter and Romboutsia.Therefore,in the decarbonization stage,the addition of PAC enhanced the the biosorption and degradation capacity of the system.(3)PAC had a positive effect on the sludge performance in the denitrification stage,but had no significant effect on the sludge microbial community structure.Among them,PAC improved the sedimentation performance of the sludge in the denitrification section,and was beneficial to the accumulation of sludge biomass in the reactor in this section,but had little effect on the sludge activity.The addition of PAC reduced the total amount of EPS,the main component PN content decreased,and the PS content increased.With the stable operation of the denitrification stage reactor,the sludge microbial community changed.However,during the same period,there was no significant difference in the microbial community composition between the control group(B-C)and the experimental group(B-PAC).PAC had no significant effect on the community composition of microorganisms at the phylum and family levels in the sludge within the denitrification stage,and had no significant effect on the activity and abundance of functional microbial genera at the genus level.PAC did not enhance the biodegradation capacity of the system,but only enhanced the biosorption capacity of the system.To sum up,the carbon capture and denitrification integrated water treatment reactor constructed in this study has a good treatment effect on various pollutants in the actual domestic sewage.At the same time,the addition of PAC has a certain positive effect on the improvement of the effluent quality and sludge performance of the system.