Membrane biofouling by chlorine resistant <i>Bacillus</i> spp.: effect of feedwater chlorination on bacteria and membrane biofouling

In this study, bacteria isolated from a lake were characterised for their chlorine resistivity and the effects of chlorination on growth, mortality, protein expression and attachment propensity towards membranes. Biofouling and membrane performance were analysed. All isolated chlorine resistant strains, characterised by 16s rRNA gene sequencing, belonged to the genus Bacillus. Chlorination caused limited effects on bacterial growth and mortality. B. safensis and B. lechinoformis suffered the maximum effects due to chlorination. Live-to-dead ratios immediately after chlorination were above 1.3, with some exceptions. The membrane pure water flux recovery was highly strain dependent. Irreversible membrane fouling was observed with B. aquimaris. Membrane flux decreased substantially during ultrafiltration of water containing chlorine resistant bacteria.本研究针对从某湖泊分离得到的细菌，开展了耐氯特性表征，并探究了氯化处理对细菌生长、死亡率、蛋白质表达及膜附着倾向的影响。同时对生物污损（Biofouling）与膜组件运行性能进行了分析。所有经16S核糖体RNA基因测序（16s rRNA gene sequencing）鉴定的耐氯分离菌株，均隶属于芽孢杆菌属（Bacillus）。氯化处理对细菌生长与死亡率仅造成有限影响，其中沙福芽孢杆菌（B. safensis）与勒奇诺芽孢杆菌（B. lechinoformis）受氯化处理的影响最为显著。氯化处理后即刻测得的活菌/死菌比值均高于1.3，仅存在少数例外情况。膜的纯水通量恢复率呈现显著的菌株依赖性。当菌株为海栖芽孢杆菌（B. aquimaris）时，观察到了不可逆膜污损。在对含耐氯细菌的水体进行超滤处理时，膜通量出现了显著下降。