Research On The Efficiency Of Purification Of Rural Sewage By Coupling Carbon Source Separation And Enhanced Ecological Treatment Technology

With the development of social economy in rural areas,the improvement of residents’ living standards and the transformation of production methods,the quality of rural water environment has gradually deteriorated.As one of the sources of polluting the rural water environment,the mission of finding a sustainable rural domestic sewage treatment based on its water quality characteristics is important.The new technology should be appropriate,efficient,low-cost,low-energy and it has become an important research content to improve the rural water environment.Compared with urban domestic sewage,the wastewater in rural area has the characteristics of high dispersion,coexistence of point-point source pollution,and low carbon-to-nitrogen ratio.In view of the disadvantages of traditional rural domestic sewage treatment processes,such as higher capital construction or operation costs,complicated maintenance,and low nitrogen removal rate under low carbon-to-nitrogen ratios,this study proposes a "carbon source separation coupling enhanced ecological treatment technology" to dispose of the decentralized domestic sewage."This technology mainly uses the biological flocculation carbon source separation process as a pretreatment technology to reduce the load capacity of the ecological bed,and the strengthening effect of the microbial electrochemistry to improve the low nitrogen removal efficiency of the traditional ecological bed under the condition of low carbon to nitrogen ratio,ensure an efficient pollutant removal rate,reduce the cost of water treatment per ton.The main research results are as follows:The carbon source separation pretreatment process uses biological flocculation adsorption carbon source separation and chemically strengthened carbon source separation technology,mainly examining the type of sludge and its dosage,mediator and its dosage,the order of sludge and mediator,The influence of biological flocculation time and other indicators on the biological flocculation process,the dosage of coagulant and flocculant,and the effect of mediator dosage on the chemically enhanced carbon source separation process.The results show that in the biological flocculation adsorption carbon source separation process,the sludge after centrifugation and ultrasonic treatment has better pollutant removal effect than the sludge without physical treatment;after adding the magnetic mediator,the sewage The SS removal rate can be increased by 10-20%,the remaining index enhancement efficiency is about 5%,and the sedimentation time is only 2-10 min,which can significantly increase the sludge sedimentation rate;the order of addition of "active sludge + magnetic powder",flocculation time 20-30 minutes can achieve higherpollutant removal rate,COD,TP,NH4+-N,SS removal rates were 28.82%,7.22%,19.19% and 85.94%.In the chemically strengthened carbon source separation process,the removal effects of the three dosing methods "PAC","PAC+PAM" and "PAC+magnetic powder" on TP are better than other indicators,among which the removal rate of "PAC+PAM" on TP can be Up to 95.16%;for COD and SS,the effect of "PAC+Magnetic Powder" is better than "PAC" and "PAC+PAM",and there is no obvious difference in the removal rate of NH4+-N between the three dosing methods.In terms of enhanced ecological technology research,the ecological bed system(CW),microbial electrochemical system(MFC),and microbial electrochemical enhanced ecological bed system(CW＿MFC)were constructed.The plant used in the ecological bed is yellow calamus,with a planting amount of 35g/L;the microbial electrochemical system uses carbon fiber cloth as the anode and cathode materials.Based on the criteria of pollutant removal effect and stable monitoring voltage,different sewage treatment systems are started.With the successful start-up of the system,the COD,TP and NH4+-N removal rates of CW＿MFC are 68.83%,66.74%and 39.75%,the highest voltage value of the system is 472 m V,the maximum power density value is 9.79 m W/m2,and the maximum current density value is 75 m A/m2.Subsequently,the pollutant removal efficiency of the three systems under intermittent flow conditions was discussed.The results show that the sewage treatment effect of the CW＿MFC system is better than that of the CW system and the MFC system,and the purpose of enhancing the removal of pollutants under the condition of low carbon to nitrogen ratio is achieved.On the first day,the removal rate of COD,TP,and NH4+-N in sewage by CW＿MFC reached 55%,50%,and 25%.Subsequently,the removal rate of COD and TP increased steadily,and the removal rate of NH4+-N first increased and then decreased.The COD removal efficiency was about 70% on the second day,the highest COD removal rate was 87.76% on the fourth day;the TP maximum removal rate was 78.8%;NH4+-N strengthened the ecosystem removal rate of NH4+-N on the second day The highest is 65.48%.Chemically enhanced carbon source separation process and biological flocculation adsorption carbon source separation process,traditional ecological bed process and enhanced ecological bed process and different decentralized rural domestic sewage treatment processes have been compared by economic and technical analysis.The results show that the biological flocculation adsorption carbon source separation technology as a pretreatment process is more suitable for rural areas with relatively backward economic conditions.In the ecological treatment process,the enhanced ecological bed system can achieve certain economic benefits while achieving a higher pollutant removal rate.The "biological flocculation carbon source separation & enhanced ecological bed" treatment hasbetter advantages in the treatment of rural domestic sewage with high dispersion,point-point source pollution coexistence,and low carbon and nitrogen.It has good engineering practical value for constructing an efficient,low-consumption,sustainable rural sewage treatment system and improving the quality of rural water environment.