Chemicals in reverse osmosis-treated wastewater: occurrence, health risk, and contribution to residual dissolved organic carbon

Abstract

The quality and safety of reverse osmosis (RO)-treated secondary wastewater, for indirect potable re-use, was assessed using a dataset of 375 chemicals measured in RO-treated wastewater. A screening health risk assessment indicated that four N-nitrosamines were of potential concern, although median concentrations of these chemicals were always below health values. The most frequently detected chemicals in RO-treated water were disinfection by-products, volatile organic compounds, metals and complexing agents, in contrast to many monitoring programs that focus on pharmaceuticals, personal care products and hormones. Frequent detections in RO-treated wastewater were most related to high concentrations in secondary wastewater, relative to limit of reporting, and the potential for chemicals to form or be added during the treatment process, rather than poor rejection by RO membranes. Between 3.7 and 10.7 μg/L of dissolved organic carbon (DOC) in RO permeate could be attributed from chemicals detected on at least one occasion, with the majority of this total attributed to chemicals detected in less than 25% of samples. While chemicals below detection may contribute a significant component of DOC, it is likely that natural organic matter and soluble microbial products still contribute the majority of DOC to RO permeate. 2A high degree of safety is demonstrated for the use of RO-treated wastewater as an indirect source of potable water.

Emerging investigators series: a steric pore-flow model to predict the transport of small and uncharged solutes through a reverse osmosis membrane

“…[1][2][3][4] However, a few small and neutral TrOCs can readily permeate through RO membranes. [5][6][7] Examples of these TrOCs are N-nitrosamines 46 including N-nitrosodimethylamine (NDMA) and volatile organic compounds (VOCs). [8][9][10] The rejection of these small and neutral TrOCs by RO membranes can vary significantly from negligible to 86% for NDMA 8 and 43-63% for some VOCs.…”

Removal Characteristics of <em>N</em>-Nitrosamines and Their Precursorsby Pilot-Scale Integrated Membrane Systems for Water Reuse

“…In many potable reuse schemes, reverse osmosis (RO) membrane processes are key components due to their high removal performance for inorganic salts and trace organic chemicals [1][2][3]. However, residual trace organic chemicals in RO permeate have been reported [4][5][6]. Among the chemicals, Nnitrosamines in RO permeate are of key concern for potable reuse, and further research and monitoring of them are recommended [4,7,8].…”

“…However, residual trace organic chemicals in RO permeate have been reported [4][5][6]. Among the chemicals, Nnitrosamines in RO permeate are of key concern for potable reuse, and further research and monitoring of them are recommended [4,7,8]. These N-nitrosamines include N- these N-nitrosamines are probable carcinogens [9], and their frequent occurrence in raw and secondary-treated wastewater [10][11][12] and reclaimed water [7,[13][14][15][16][17] has been reported.…”

A rapid and reliable technique for N -nitrosodimethylamine analysis in reclaimed water by HPLC-photochemical reaction-chemiluminescence

“…Potable water reuse refers to the use of reclaimed wastewater as a source of drinking water. A major challenge to implementing potable water reuse is the ubiquitous occurrence of trace organic chemicals (TrOCs) in reclaimed water that could pose a potential threat to public health (Lampard et al, 2010;Debroux et al, 2012;Linge et al, 2012;Scott et al, 2014). These TrOCs include pharmaceuticals, pesticides, endocrine disrupting compounds, and disinfection by-products (Luo et al, 2014).…”