The reverse osmosis (RO) system is widely applied to produce reclaimed water for high-standard industrial use. Chlorine disinfection is the main biofouling control method in the RO systems for wastewater reclamation. However, researchers reported the adverse effects of chlorine disinfection which aggravated biofouling in laboratory-scale RO systems. In this study, four parallel 4-inch spiral wound RO membranes were used to study the effect of chlorine on biofouling in a pilot-scale RO system. The free chlorine dosages in four experimental groups were 0, 1, 2 and 5 mg/L, respectively. After continuous chlorination and dechlorination, the feed water entered the RO system. It was found that chlorine pretreatment caused a 1.9–36.7% increase in relative feed water pressure of the RO system, suggesting that chlorine aggravated the membrane fouling in the pilot-scale RO system. The microbial community structures of living bacteria in the feed water of the RO system were determined by the PMA (propidium monoazide)-PCR method and showed that the relative abundance of chlorine-resistant bacteria (CRB) was significantly increased after disinfection. Nine major genera which maintained higher relative abundance in experimental groups with high chlorine dosage were considered as possible key species causing membrane fouling, including Pedobacter, Clostridium and Bradyrhizobium.

反渗透（RO）系统广泛应用于生产高标准工业用再生水。氯消毒是废水回收反渗透系统中主要的生物污垢控制方法。然而，研究人员报告了氯消毒的不利影响，这会加剧实验室规模的 RO 系统中的生物污垢。在这项研究中，四个平行的 4 英寸螺旋缠绕 RO 膜用于研究氯对中试规模 RO 系统中生物污垢的影响。四个实验组的游离氯用量分别为0、1、2和5mg/L。进水经过连续氯化脱氯后进入反渗透系统。发现氯预处理导致 RO 系统的相对给水压力增加 1.9-36.7%，表明氯会加剧中试规模 RO 系统中的膜污染。RO系统给水中活菌的微生物群落结构通过PMA(propidium monoazide)-PCR法测定，结果表明消毒后耐氯菌(CRB)的相对丰度显着增加。在高氯剂量实验组中保持较高相对丰度的九个主要属被认为可能是导致膜污染的关键物种，包括足杆菌、梭状芽孢杆菌和慢生根瘤菌。