title: N-nitrosamine rejection by reverse osmosis membranes: a full-scale study.
abstract: This study aims to provide longitudinal and spatial insights to the rejection of N-nitrosamines by reverse osmosis (RO) membranes during sampling campaigns at three full-scale water recycling plants. Samples were collected at all individual filtration stages as well as at a cool and a warm weather period to elucidate the impact of recovery and feed temperature on the rejection of N-nitrosamines. N-nitrosodimethylamine (NDMA) was detected in all RO feed samples varying between 7 and 32 ng/L. Concentrations of most other N-nitrosamines in the feed solutions were determined to be lower than their detection limits (3-5 ng/L) but higher concentrations were detected in the feed after each filtration stage. As a notable exception, in one plant, N-nitrosomorpholine (NMOR) was observed at high concentrations in RO feed (177-475 ng/L) and permeate (34-76 ng/L). Overall rejection of NDMA among the three RO systems varied widely from 4 to 47%. Data presented here suggest that the feed temperature can influence rejection of NDMA. A considerable variation in NDMA rejection across the three RO stages (14-78%) was also observed. Overall NMOR rejections were consistently high ranging from 81 to 84%. On the other hand, overall rejection of N-nitrosodiethylamine (NDEA) varied from negligible to 53%, which was considerably lower than values reported in previous laboratory-scale studies. A comparison between results reported here and the literature indicates that there can be some discrepancy in N-nitrosamine rejection data between laboratory- and full-scale studies probably due to differences in water recoveries and operating conditions (e.g. temperature, membrane fouling, and hydraulic conditions).
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil Mining and Environmental Engineering, The University of Wollongong, NSW 2522, Australia.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujioka
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Khan
authors.forename: James A
authors.initials: JA
authors.lastname: McDonald
authors.forename: Annalie
authors.initials: A
authors.lastname: Roux
authors.forename: Yvan
authors.initials: Y
authors.lastname: Poussade
authors.forename: Jörg E
authors.initials: JE
authors.lastname: Drewes
authors.forename: Long D
authors.initials: LD
authors.lastname: Nghiem
mesh_terms: D005374:Filtration; D008567:Membranes, Artificial; D009602:Nitrosamines / Q000737:chemistry*; D009995:Osmosis; D018508:Water Purification / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D009602:Nitrosamines
keywords: Full-scale operation; N-nitrosamines; NDMA; Reverse osmosis (RO) membranes; Water reuse