Study On The Treatment Of Rural Sewage By Hybrid Anaerobic Technology

In recent years,with the rapid improvement of economic and social development in rural areas and the living standards of residents,the amount of rural sewage is increasing,and rural sewage discharge has become one of the important factors affecting rural water environment.In view of the problems of conventional single anaerobic biotechnology to treat low-concentration rural sewage with long startup time and improved treatment efficiency,this thesis carried out research on enhanced hybrid anaerobic technology.Compared with conventional anaerobic treatment technology,the hybrid anaerobic technology enhances the mass transfer and microbial reaction.The sludge concentration,matrix mixing and degradation driving force of the treatment system are high,the impact load resistance is strong,and the startup time is short.The structure of anaerobic baffled zone and filter zone was optimized by constructing a small-scale experimental device for reinforced anaerobic reactor.The start-up operating conditions,start-up performance,pollutant removal effect during stable period and the variation of related indicators along the process were investigated.The impact load research under hydraulic impact and water quality impact was carried out separately;based on the 16S rDNA metagenomic high-throughput sequencing technology,the dominant microbial population and abundance of anaerobic baffled area were comprehensively characterized.The main findings are as follows:During the start-up period,the influent COD concentration was 187³80 mg/L,the ORP was-100^-300 mV,the pH was 6.8⁷.0,and the COD removal rate reached 70.7%after 25 d.The elastic filler film was better,and the reactor was successfully started.During the stabilization period,as the HRT decreased from 24 h to 18 h,12 h,8 h and 5 h,the COD removal rate first increased and then decreased,with an average of 79.5%;the COD removal contribution rate?4.5%?in the AF was much smaller than the ABR?75.0%?;the percentage of CH4 in biogas decreased with the decrease of HRT.When OLR was 0.13¹.16 kg COD/?m³·d?,the gas production of CH₄ increased with the increase of OLR,the relationship of CH₄ and OLR was:CH₄?g?=5.56×OLR^0.80?R²=0.80?;the COD removal contribution rate of each cell basically showed a decreasing trend along the path,in which the front two cells played a major role in COD degradation,which was 56.8%⁶0.3%,DOM decomposed and transformed along each cell,and the concentration gradually decreased,which was consistent with the actual removal effect of COD.The water quality impact and hydraulic impact test of the reactor were carried out respectively.The results showed that the reactor could recover the state before the impact load 10 h after the water shock and 6 h after the hydraulic shock.The enhanced hybrid anaerobic reactor had good treatment effect,strong impact load resistance,simple operation and maintenance,and can provide reference for small decentralized rural sewage treatment facilities?<5 m³/d?.By analyzing the EPS three-dimensional spectrum,it was concluded that the EPS content of the sludge in each chamber of the reactor increased with the running time.Under the same HRT,the EPS content of the sludge gradually decreased along the path;the sludge was scanned by electron microscopy.The floc structure was relatively dense,the number of bacterial gums was abundant,and the pores and channels for internal material exchange were very clear.The surface of the sludge was mainly cocci,and the bacteria and filamentous bacteria were less.The eugenic and archaeal community composition of each cell sludge in the anaerobic baffled area was comprehensively characterized.The results showed that the microbial diversity in the first cell was the highest,while the microbial abundance in the second cell was the highest.The sum of the abundances of fermentative bacteria and acetogenic bacteria?Firmicutes,Chloroflexi,Proteobacteria and Bacteroidetes?at the level of the phylum was74.5%,86.7%,78.5%and 78.9%in each cell,respectively.The sum of abundance of methanogens?Methanomicrobia,Methanobacteria and Thermoplasmata?at the phylum level was 93.7%,96.4%,98.2%and 97.7%in each cell,respectively.It can be seen that the abundance of methanogens increased gradually along the cell.