水厂生物活性炭工艺进出水中DON变化及其成因分析

Variation of DON in Inflow and Treated Water of BAC Process and Analysis of the Cause in WTP

生物活性炭(biological activated carbon, BAC)是饮用水处理中控制溶解性有机氮(dissolved organic nitrogen, DON)的关键环节。论文利用中试试验考察了不同使用年限BAC对DON的控制效能,探讨了处理前后DON成分的变化,并通过生物量、生物活性、微生物种群结构以及可溶性微生物产物(soluble microbial products, SMPs)的变化来探究其致因。研究结果表明,BAC使用年限对其控制DON的效能有一定的负面影响,使用年限为0.3、2.0、5.0、10.0年的BAC对DON的去除率分别为39.69%~66.96%、10.10%~39.78%、-4.18%~29.63%、-20.88%~19.87%。BAC处理改变了出水中DON的含量及组成组分,出水中SMPs类物质含量增加,且主体成分为蛋白质、氨基糖;使用年限延长会导致BAC生物膜厚度增厚、生物种群组成发生改变,在一定程度上促进了净化过程中SMPs、胞外聚合物(extracellular polymeric substance, EPS)的生成,导致出水中DON含量增加,弱化了DON的控制效果。论文结果可为水厂实际运行中DON的控制提供一定的参考。

Biological activated carbon(BAC) is the key link to control dissolved organic nitrogen(DON) in drinking water treatment. In this paper, the pilot test was used to investigate the control effectiveness of BAC on DON with different service life. The changes of DON components before and after treatment were discussed, and the causes were explored through the changes of biomass, biological activity, microbial population structure and soluble microbial products(SMPs). The results showed that the service life of BAC had a certain negative impact on its efficacy in controlling DON. The removal rates of DON by BAC with service life of 0.3, 2.0, 5.0 years and 10.0 years were 39.69%~66.96%, 10.10%~39.78%,-4.18%~29.63% and-20.88%~19.87%, respectively. BAC treatment changed the content and composition of DON in the treated water, the content of SMPs in the treated water increased, and the main components were protein and amino sugar. The extension of service life would lead to the thickening of BAC biofilm and the change of biological population composition, which would promote the generation of SMPs and extracellular polymeric substance(EPS) in the purification process to a certain extent, leading to the increase of DON content in the treated water, and weakening the control effect of DON. The results of this paper can provide some reference for the control of DON in the actual operation of WTP.