水厂21是加利福尼亚州奥兰治县的一家先进废水处理设施，回收了奥兰治县环卫区经处理的约57毫升/天（15毫克/天）活性污泥废水。通过反渗透对经过预处理的废水进行脱盐，可以获得安全的饮用水，但给水中的微生物和化学物质会迅速阻碍膜通量，降低电厂效率，增加处理成本。研究了21号水厂在低氯和高氯条件下生物膜形成的性质。生物化学物质的积累与膜通透性的丧失有密切关系。 高氯残留破坏了膜结构，降低了矿物截留能力。包括30个参考文献、表格、图表。

Water Factory 21, an advanced wastewater treatment facility in Orange County, California, reclaims approximately 57 ML/d (15 mgd) of activated sludge, treated effluent from the Orange County Sanitation Districts. Demineralization of pretreated wastewater by reverse osmosis yields safe, potable supplies, but micro-organisms and chemical substances in the feedwater rapidly impede membrane flux, reducing plant efficiency and increasing treatment costs. The nature of biofilm development was studied at Water Factory 21 under low and high chlorine conditions. Close relationships were found between the accumulation of biochemical material and the loss of membrane permeability. High chlorine residuals damaged the membrane structure and reduced mineral rejection capacity. Includes 30 references, table, figures.