Startup And Operation Of Bladder-Type Anaerobic Sludge Digestion

With the growing scale of urban sewage,a lot of sludge is difficult to deal with and causing a lot of problems.Because of low temperature and low organic matter.The sludge anaerobic digestion project in the north of China is in the low yield of biogas production and incomplete degradation of organic matter,so how to optimize from the pool type and operating conditions is currently urgent to be solved,while the sludge anaerobic digestion of microorganisms rarely focus on the function and structure of the flora in-depth study.In this study,the start-up process of sludge anaerobic digestion was operated in the CSTR small scale divice,and the start-up of the bladder sludge anaerobic digestion reactor was studied based on the conclusion of CSTR.At the same time,we analyzed the stable operation data of the bladder pool for more than five months and Chicken manure conditioning for two months.The effects of temperature,stirring intensity and sludge loading on the anaerobic digestion were summarized.Finally,through the high-throughput sequencing of digested sludge,the microbial mechanism of anaerobic digestion was analyzed from the population structure of archaea and bacteria.The results show that the organic matter reduction rate(42.7%)at the medium temperature reactor is slightly higher than the organic matter reduction rate(37.8%)at the room temperature,but the advantage is not obvious.The anaerobic digestion reaction was started at 27-30 ° C in three stages.The VFA was accumulating in the early stage which is the microbial domestication period;The alkalinity increased rapidly in the medium term which is microbial maturity stage;The VSS reduction rate was up to 52 percent in the later stage of the alkaline fermentation phase,and the highest biogas yield was 0.6946 m3 / kg removal of VSS.During stable operation of bladder type anaerobic digestion system,VSS reduction rate of the whole is greater than 40%,from 42.74% to 56.35% range,biogas yield reached 1.11 m3 / kg removed VSS,with an average of 0.84 m3 / kg removed VSS.After the sludge was digested,the average capillary water intake increased by 7.75 times and the dehydration performance was worse.The study showed that Proteobacteria,Chloroflexi,and Firmicutes were dominant bacterial community,and Anaerolineae,Clostridia,Alphaproteobacteria,Bacilli,Synergistia and Betaproteobacteria were dominant bacterial phylum.While the dominant archaea phylum is Methanothrix,Methanospirillum,methanolum,Methanosphaera.In the methane-producing bacteria,70% of the methane bacteria produce energy from CH4 and CO2,and 30% using CO2 / H2,diglycol,or formic acid.In the high load stage of the bladder pool,the effect of stirring intensity on VSS reduction rate is very small,and the increase of the stirring time caused the tendency thatbiogas yield increase first and then decrease,the biogas production is the largest at 14 h / d.When the temperature increased from 28 ± 1 ? to 32 ± 1 ?,VSS reduction rate increased by about 20%,biogas production rate had no obvious change below 31 ? while significantly increased at 32 ± 1 ?.The removal rate of organic matter decreases with the increase of sludge dosing rate,and the biogas yield increased rapidly and then decreases slightly with the increase of sludge dosing rate.Sludge anaerobic digestion in the chicken manure ratio of 1: 4 digestion effect is greater than 1: 9,in the 1: 4 chicken manure,VFA concentration is the highest is 456.1mg / L,biogas production increased by 91.2% compared with the single sludge anaerobic fermentation biogas in the blank group.The direct operating cost of per ton of sludge(water content of 80%)is 96.90 yuan.