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针对建筑二次供水管壁生物膜对饮用水的生物安全性构成的潜在威胁,采用生物膜反应器(BAR)模拟二次供水管道,研究氯和氯胺冲击消毒过程对管壁生物膜的细菌总数、大肠杆菌和异养菌(HPC)灭活效果以及对生物膜结构的影响.结果表明,在第80天时生物膜中生物量达到最大,生物膜宏基因组分析表明,厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和拟杆菌(Bacteroidetes)为优势菌种.冲击消毒对生物膜的灭活效能与氯和氯胺的质量浓度以及CT值有关,在相同CT值条件下,高质量浓度氯和氯胺的灭活效果更佳.氯和氯胺的生物膜灭活效果对比可以看出,在低投量条件下,氯的细菌总数和大肠杆菌灭活效果好于氯胺,但氯的HPC灭活效果弱于氯胺;在高投量条件下,消毒剂质量浓度和CT值与生物膜的灭活效果无明显相关性,可以达到快速消毒的效果.在氯和氯胺的投加质量浓度为3.0 mg/L、CT值300~400 mg·min/L的最佳冲击消毒条件下,生物膜中细菌总数、大肠杆菌和HPC的灭活率均达到95%以上.从生物膜的表面特性分析可以看出,冲击消毒后生物膜结构破坏明显,生物膜变薄或脱落;氯冲击消毒对生物膜的破坏和削减程度优于氯胺,更有利于管道生物膜的控制.
In view of the potential threat to the biosafety of potable biofilm in secondary water supply system, a biofilm reactor (BAR) was used to simulate the secondary water supply pipeline to study the effects of chlorine and chloramine impact sterilization on the biofilm bacteria Total number, inactivation of E.coli and heterotrophic bacteria (HPC) and their effect on the biofilm structure were studied.The results showed that the biofilm biomass reached the maximum on the 80th day, and the biomembrane metagenomic analysis showed that Firmicutes ), Proteobacteria and Bacteroidetes were the dominant species.The biofilm inactivation efficiency of impact sterilization was related to the concentration of chlorine and chloramine and the CT value. Under the same CT value, the high quality Concentration of chlorine and chloramine inactivation effect is better.Chloride and chloramine biofilm inactivation effect comparison can be seen in the low dosage conditions, the total number of bacteria and E. coli chlorine inactivation effect is better than chloramine, but Chlorine inactivation of HPC is weaker than that of chloramine.Under the conditions of high dosage, there is no significant correlation between the concentration of disinfectant and the inactivation effect of biofilm, which can achieve the effect of rapid disinfection.Under the conditions of chlorine and chloramine Dosing mass concentration of 3.0 mg / L, CT Under the optimal impact and disinfection conditions of 300 ~ 400 mg · min / L, the total number of bacteria in the biofilm, the inactivation rates of Escherichia coli and HPC reached more than 95% .Based on the analysis of surface characteristics of biofilms, The structure of the biofilm was destroyed obviously, and the biofilm became thin or peeled off. The destruction and reduction degree of the biofilm by chlorine impact disinfection was better than chloramine, which was more conducive to the control of biofilm.