三氯卡班对污水生物脱氮及N_(2)O释放特征的影响

Impact of Trichlorocarban on Biological Nitrogen Removal and N_(2)O Emission from Wastewater

为了探究三氯卡班(TCC)对废水生物脱氮及温室气体N_(2)O释放的影响,在中温条件下构筑了序批式反应器,研究TCC浓度对生物脱氮及N_(2)O释放特征的影响,并通过分析TCC对反硝化污泥特征、微生物代谢活性的影响来揭示相关机制。结果表明,当TCC浓度达到5 mg/L以上时会抑制反硝化系统对COD和TN的去除盩CC浓度达到10 mg/L时才抑制NH4+-N的去除。N_(2)O释放速率随着TCC浓度的增加而升高,高浓度TCC组别N_(2)O的释放速率可提高至8.9~10.2μg/min。高浓度TCC降低了污泥浓度及有机质占比,提高了污泥体积指数,并延长了毛细吸水时间。此外,高浓度TCC刺激了胞外聚合物(EPS)分泌,但降低了EPS内蛋白质/多糖(PN/PS)值。TCC改变了反硝化脱氮系统内微生物的代谢活性,高浓度TCC导致活性氧和乳酸脱氢酶的释放。

A sequencing batch reactor was established under mesophilic conditions,the influence of trichlorocarban(TCC)concentration on biological nitrogen removal and N_(2)O emission characteristics was examined,and the underlying mechanism was elucidated through analyzing the effects of TCC on denitrifying sludge properties and microbial metabolic activity,so as to investigate the impact of TCC on biological nitrogen removal and the emission of greenhouse gas N_(2)O from wastewater.When the concentration of TCC exceeded 5 mg/L,the removal efficiencies of COD and TN in the denitrification system were adversely affected.Furthermore,at a TCC concentration reaching 10 mg/L,the removal of NH4+-N was also inhibited.The rate of N_(2)O release was positively correlated with the concentration of TCC exposure,with the high-concentration TCC group exhibiting an increase in N_(2)O release rate to 8.9-10.2μg/min.The elevated concentration of TCC led to a reduction in sludge concentration and organic matter proportion,an increase in the sludge volume index,and an extension of capillary suction time.Furthermore,elevated concentrations of TCC induced the secretion of extracellular polymeric substances(EPS),while concurrently reducing the protein/polysaccharide(PN/PS)ratios within EPS.TCC altered the metabolic activity of microorganisms within the denitrification system,and elevated concentrations of TCC resulted in the release of reactive oxygen species and lactate dehydrogenase.