新型不锈钢复合管道生物膜形成特性与冲击消毒效能

Characteristics and shock disinfection efficiency of biofilm of a new stainless steel composite pipeline

通过生物膜环形反应器(BAR)研究在市政和建筑区域的供水系统中的新型不锈钢复合管管壁生物膜中微生物形成特点、微生物腐蚀特性以及冲击消毒控制措施,考察不锈钢复合管材管壁生物膜中微生物生长情况及微生物对管道的腐蚀速率,了解氯消毒剂对管壁生物膜中微生物的灭活效能。研究结果表明:在含有余氯的市政和建筑区域供水管网系统中,不锈钢复合管道在模拟实验开展80 d后仍会出现明显的生物增殖现象,在100～110 d期间生物量达到峰值,出现浊度和微生物超标的现象;管壁生物膜中微生物种类丰富,其中含有多种致病菌、耐氯病原菌以及易造成金属腐蚀的菌属,使供水的生物安全性和化学安全性受到潜在威胁;水中微生物造成不锈钢复合管材腐蚀电流密度增大,腐蚀电位降低,腐蚀速率明显增大;冲击消毒的氯质量浓度越高、消毒时间越长,生物膜微生物灭活效果越好;当氯质量浓度为5 mg/L,消毒60 min时,铁细菌、异养菌及其余细菌均可完全灭活;冲击氯消毒后管壁生物膜大量剥离和脱落,生物膜形态破坏明显,且消毒时间越长,生物膜破坏程度越大,可以有效控缓解生物对不锈钢复合管道的腐蚀,保障供水安全。

By using the biofilm annular reactor(BAR),the characteristics of microbial growth and microbial corrosion,and control measures of shock disinfection of a new stainless steel composite pipeline in the water supply system of municipal and construction area were studied.The microbial growth on the stainless steel composite pipeline wall,corrosion rate of the pipeline caused by microorganism,and inactivation efficiency of chlorine disinfection on biofilm were also investigated.The results show that in the water supply pipe network system of municipal and construction area with residual chlorine,biofilm proliferation of stainless steel composite pipeline is obvious after 80 d of operation.During 100-110 d,the biomass reaches the peak,and both the turbidity and microbial index exceed the standard values.The biofilm of the wall has a diversity of microorganisms in it,which contains a variety of pathogens,chlorine resistant pathogens and bacteria that can cause metal corrosion,posing a potential threat to the biosafety and chemical safety of drinking water.With microorganisms in water,the corrosion current density of the stainless steel composite pipeline increases,the corrosion potential decreases and the corrosion rate increases obviously.With high mass concentration of chlorine and long sterilization time,the inactivation effect of biofilm microbes is better.When the chlorine mass concentration is 5 mg/L,iron bacteria,heterotroph and other bacteria can be completely inactivated when sterilized for 60 min.After the shock of chlorine disinfection,the biofilm on the wall peels off,and biofilm morphology is damaged.The longer the disinfection time is,the greater the degree of biofilm damage is,which can effectively control the corrosion of stainless steel composite pipeline caused by biofilm and assure water safety.