原水生物膜预处理工艺对有机碳源的响应特征--以脱氮性能与菌群结构为例

Characterization of raw water biofilm pretreatment processes in response to organic carbon sources:An example of nitrogen removal performance and bacterial community structure

原水生物膜预处理系统运行性能受限于原水水质特征,试验以模拟污染原水为处理对象,以彗星式纤维填料和活性炭填料为生物膜载体构建了实验室规模的原水生物膜预处理系统,采用批次试验探究系统运行性能与菌群结构对不同有机碳源乙酸钠和腐殖酸的响应特征.试验结果表明,原水生物膜预处理系统能长时间稳定运行,系统平均氨氮去除率(ARE)为90.1%.乙酸钠对两种填料生物膜的氨氮去除性能几乎无影响.以腐植酸为有机碳源具有更强的硝化能力,取得最高ARE值90.5%±5.6%.乙酸钠能够促进彗星式纤维填料生物膜胞外聚合物(EPS)的形成,腐殖酸会降低EPS中PN含量.以活性炭为载体明显增加了EPS的PN/PS值,且具有较高的菌群多样性,更有利于生物膜的形成.生物膜样品中,占据前三位的门是Proteobacteria､Planctomycetes和Acidobacteria.彗星式纤维填料生物膜,乙酸钠和腐植酸分别强化了优势门Proteobacteria(53.9%)细菌和优势属Nitrospira(10.7%)的累积.以彗星式纤维填料与活性炭为载体生物膜样品优势属分别为Nitrospira和Aridibacter.腐殖酸更有利于Nitrospira和Bdellovibrio的富集,乙酸钠更有利于Aridibacter的富集.

The operation performance of the raw water pretreatment biofilm system is limited by the water quality of raw water.A laboratory-scale raw water pretreatment biofilm system was constructed with synthetic polluted raw water as the treatment object and comet type fiber filler and activated carbon filler as biofilm carriers.Batch tests were conducted to explore the response characteristics of operation performance and bacterial community structure to different organic carbon sources including sodium acetate and humic acid.Experimental results showed that the raw water pretreatment biofilmsystem operated stably for a long time with the average ammonia nitrogen removal efficiency(ARE)of 90.1%.Sodium acetate had little effect on the ammonia nitrogen removal performance of biofilm attached on two kinds of carriers.Stronger nitrification ability with the highest ARE of 90.5%±5.6%was obtained using humic acid as the organic carbon source.Using comet type fiber filler as biofilm carrier,sodium acetate promoted the formation of extracellular polymer(EPS)in biofilm,and humic acid reduced the PN content in EPS.The usage of activated carbon as the biofilm carrier significantly increased the PN/PS value of EPS,and had higher bacteriall diversity,which was more conducive to the formation of biofilm.In the biofilm samples,the top three phyla are Proteobacteria,Planctomycetes,and Acidobacteria.When comet type fiber filler was used as biofilm carrier,sodium acetate and humic acid enhanced the accumulation of Proteobacteria(53.9%)and Nitrospira(10.7%),respectively.The dominant genera of biofilm samples of comet type fiber filler and activated carbon were Nitrospira and Aridibacter,respectively.Humic acid was more conducive to the enrichment of Nitrospira and Bdellovibrio,and sodium acetate was more conducive to the enrichment of Aridibacter.