Study On The Start-up Of Anammox With Sulfate As Electron Acceptor And Microbial Community Succession

In recent years, since sulfate reducing anaerobic ammonia oxidation has been found, people has new views on anaerobic biological nitrogen removal process. The discovery of sulfate reducing anaerobic ammonia oxidation could lead to new way to treat wastewater of low ratio of carbon to nitrogen and containing sulfate. But the sulfate reducing anaerobic ammonia oxidation was difficult to initiate.And So far, there were few reports on microbial community succession and operating conditions of the sulfate reducing anaerobic ammonia oxidation. The goal of this study is therefore to solve the problem of the long start-up period of cultivating anammox bacteria.So,in a UASB reactor, inoculated anaerobic granular sludge, after the successful development of anaerobic ammonia oxidation, NO2- was replaced by SO42- gradually to setup a new anammox pathway, and SO42- finally became the electron acceptor of anammox process. Through PCR-DGGE technology research of the microbial community structure in the transfering process of the new anaerobic ammonia oxidation. The different operation conditions on the sulfate-reducing anaerobic ammonium oxidation were studied.The main results of this thesis were as follows:(1) In a upflow sludge bed reactor(effective volume of 6.3L) inoculated 2.0L anaerobic granular sludge which was from the UASB of Xi’an Guo-wei starch factory. And the sludge is 1.05 mm in average diameter(particle size distribution: 0.55mm-2.87mm),31430 mg/L,22440 mg/L in VSS and 38.7-76.8m/h in sedimentation velocity. Controlling reactor pH=7.6±0.2, HRT=1d, the temperature of 35±1℃,after 86 days’ operation, NH4+ and NO2- removal rates achieved 95.2% and 98.9% while concentration of ammonium nitrogen and nitrite of influent were 80 mg/L and 100 mg/L, respectively. The removal molar ratio of NO2- and NH4+ was 1.18:1, and nitrite-reducing anaerobic ammonia oxidation was established. Then sulfate replaced nitrite in the influent gradually, the sulfate reducing anaerobic ammonium oxidation process was achieved successfully after 177 days. The removal rate of ammonium nitrogen and sulfate were up to 58.9% and 15.7%, the removing load of ammonium nitrigen and sulfate were 74.3 mg/L·d and 77.5 mg/L·d while concentration of ammonium nitrogen and sulfate of influent were 130 mg/L and 500 mg/L, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Microorganisms in sludge from coccus into short bacilli.(2) The results of DGGE show that the nitrite-reducing anaerobic ammonium oxidation bacteria were named Uncultured Candidatus Brocadia sp.clone YLJ-1 in GenBank(KM583866),and the similarity with GenBank Brocadia Sinica and Candidatus JPN1 genes(AB565477) was 100%. the advantages of sulfate-reducing anaerobic ammonium oxidation sludge bacteria were named Uncultured Bacillus sp.clone YLJ-2(KP336392), the similarity with Bacillus benzoevorans 16 S rRNA gene(Y14693) was 100%. Construction of phylogenetic tree analysis showed that nitrite reducing anaerobic ammonia oxidation bacteria and sulfate reducing anaerobic ammonia oxidation bacteria larger evolutionary distances, and Lower homology.(3) With the action of sulfate reducing anaerobic ammonia oxidation bacteria, ammonium and sulfate into N2 and sulfur, respectively. According to the reaction of...