| Sulfate-reducing ammonium can be used to remove ammonia and sulfate from wastewater at same time with high efficiency and no twice pollution.In the field of wastewater treatment,it provides a novel idea for simultaneous removal technology of ammonia and sulfate.But at present,S-anammox can not be widely used flowing from its long starting-up time and unclear mechanism.In this work,Sulfate-reducing ammonium process characteristics has been tested under inorganic conditions and substrates removal capacity also have been investigated at the same time.Also research of microbial morphology and population structure composition feature in the process of S-Anammox provide practice foundation for high concentration of ammonia and sulfate containing wastewater treatment.This work adopts self-designed anaerobic biological reactor,using ammonium and sulfate as substrate sludge to start S-Anammox,to explore wastewater treatment performance and the effect of various environmental factors.High-throughput sequencing has been used to analyze the microbial community structure of the sludge,providing theoretical support for the reaction mechanism analysis.In the 103 days acclimation process,S-Anammox started at 26 th which ammonia and sulfate removed at same time.The substrates removal efficiency is high which.NH4+-N and SO42-can reach 92.5% and 59.3%,respectively.But at high substrate concentration(NH4+-N is 180.0mg/L,SO42-is 1050.0mg/L),the influent has a certain toxic effect on S-Anammox bacteria.It is found that the reaction is an acid producing reaction,which is different from the traditional anaerobic ammonia oxidation reaction by monitoring the pH.In the test of influencing factors,the following conclusions can be concluded.Improving the influent N/S can enhance the removal rate of the matrix of NH4+-N and SO42-;when the HRT is 18 h,the substrate removal rate can reach 73.1% and 32.8%,respectively.And removal load are the most ideal which are 0.059 KgN/m3·d and 0.180 KgS/m3·d,respectively.Moderate NO3--N or NO2— is favorable to the reaction;organic matter inhibited the removal of the ammonia and sulfate,but a high concentration(800mg/L-1500mg/L)will make the dominant species SAnammox bacteria converting to sulfate reducing bacteria.In this experiment,13 phylums of bacteria were found in the anaerobic bioreactor by highthroughput sequencing,which are accounted for 92.9%-93.7%.Among them,there are some common phylums of anaerobic reactor such as: Proteobacteria,Chloroflexi,Bacteroidetes,and Chlorobi,etc.A number of new finding and unusual bacteria also found in this anaerobic reactor,for example: Gemmatimonadetes,Cyanobacteria,Armatimonadetes,Acidobacteria,Planctomycetes,Nitrospirae,2 uncultivated bacteria Candidate_division_OD1 and SHA-109.In addition,Ignavibacteriales is accounted for 12.6%-13.1% with few awareness.It is likely to be involved in the S-Anammox reaction.Three genes of Planctomyetes bacteria have been detected in the reactor,which are Pla4_lineage,Planctomycetaceae and SM1A02,representing 1.5%-3.3%;2 AOBs having 1.8%-2.3%;4 denitrifying bacteria acounting 11.2%-12.4%.In addition,no SRB bacteria were found in this study,so S2-was not the product of S-Anammox reaction.In the continuous operation test,S-Anammox N/S conversion ratio has been unstable,while the microbial sequencing proved that reactor has many kinds of denitrification bacteria,which shows that the S-Anammox reaction is a multistep reaction which environmental conditions may affect the reaction.Influent N/S ratio has a obvious effect on nitrogen loss:when the low N/S reaction,NO2-and NO3-apperar at the same time;a high N/S ratio not only can significantly improve the conversion rate of NH4+-N,but also can improve the nitrogen loss. |
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