In this study, an integrated investigation to the microbial activities, extracellular polymeric substance (EPS), microbial community and function of anammox granular sludge (AnGS) was performed.Results showed that AnGS at 0.5-1.0 mm had the highest average specific anammox activity (SAA) of 345.9 mg NH4+-N·gVSS-1·d-1, but AnGS at 1.0-1.5 mm with higher SAA might lead to better nitrogen removal efficiency. The content of slime EPS and SAA achieved positively correlation with R2 of 98.11%, while protein/polysaccharide ratio of slime EPS and sludge volume index achieved negatively correlation with R2 of 99.13%. Cadidatus Broccadia and Denitratisoma were positive correlations and most abundant in AnGS 0.5-1.0 mm of 20% and AnGS 1.0-1.5 mm of 37%, respectively. AnGS at 0.5-1.0 mm exhibited higher energy metabolism which mostly contributed to produce protein. The study provides new insights into the mechanisms of AnGS about 1 mm playing more important role in nitrogen removal performance.
Keywords: Anammox granular sludge; Extracellular polymeric substance; Gene functions; Microbial community network; Protein/polysaccharide ratio.
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