An anaerobic expanded granular sludge bed reactor(EGSB)was used to treat simulated wastewater containing COD,ammonia and nitrate nitrogen to rapidly establish anaerobic ammonium oxidation(Anammox)process in a high-concentration organic wastewater treatment system.By inoculating a small amount of Anammox sludge and gradually increasing the concentration of ammonia nitrogen,the system successfully started the Anammox reaction after 58d of continuous operation,at which the total nitrogen and COD removal efficiencies were stable to over 97%and 98%,respectively.Mass balance showed that the contribution of Anammox reaction pathway to nitrogen removal gradually increased,and dissimilatory nitrate reduction(DNRA)coupled with Anammox and denitrification together contributed to simultaneous nitrogen and carbon removal in the system.Microbial community analysis found that the relative abundance of Candidatus Kuenenia rapidly increased from 0.27%to 35.87%,and DNRA bacteria(Ignavibacterium,Thermogutta)and denitrification bacteria(Azospira,Gp3)co-existed in the system.The key functional genes of Anammox,DNRA,nitrate reduction and nitrite reduction were detected by gene annotation method.During the operation,the granular sludge turned reddish in color and its particle size increased.Extracellular polymeric substance(EPS)analysis showed an increase in polysaccharide(PS)and protein(PN)contents and a decrease in PN/PS.Three-dimensional fluorescence spectroscopy revealed an increase in humic acid-like substances.These results of the study provide a novel process pathway for efficient treatment of high concentration organic nitrogenous wastewater.
维普
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