Analyzing and verifying the association of spiral-wound reverse osmosis membrane fouling with different secondary effluents: full-scale experiments.

• The fouling potential of two kind secondary effluents were compared in a long-term. • The secondary effluent from municipal sewage caused more serious membrane fouling. • More foulants deposited on the leading membranes in both two reclaimed water plants. • Several bacteria species which could cause serious membrane biofouling were verified. • Organics facilitated biofouling while high ion concentration restrained biofouling. In order to analyze and verify the association of the reverse osmosis (RO) membrane fouling with water quality in full-scale plants, two RO systems (40, 000 m3/d and 20, 000 m3/d) treating different secondary effluents were operated in parallel. The quality of secondary effluents and the performance of RO systems were monitored over 12 months. Difference in foulants distribution and fouling layer composition between the two systems were evaluated by membrane autopsy and foulants characterization. Results verified that: 1) the secondary effluent from municipal sewage caused more serious membrane fouling; 2) more foulants deposited on the surface of leading membrane both in two systems (3.11 ± 0.15 g/m2 and 2.93 ± 0.13 g/m2); 3) the microbial community on the RO membrane surface contained more colonizing bacteria in the system treating municipal sewage secondary effluent ; 4) organics in the secondary effluent facilitated biofouling while higher ion concentration restrained biofouling. [ABSTRACT FROM AUTHOR]