Validating the rejection of trace organic chemicals by reverse osmosis membranes using a pilot-scale system

Abstract

Nghiem, L. D. (2015). Validating the rejection of trace organic chemicals by reverse osmosis membranes using a pilot-scale system. Desalination, Validating the rejection of trace organic chemicals by reverse osmosis membranes using a pilot-scale system Abstract A protocol to validate the rejection of organic chemicals of potential health risk by low pressure reverse osmosis (LPRO) membranes was developed for decision making support regarding the monitoring level required for potable water reuse. Ten organic chemicals were selected for evaluation, based on their recorded usage, the scarcity of rejection data, and difficulty in analytical determination at concentrations relevant to their potential impact on human-health. An analytical method was developed for these organic chemicals. The target rejections of 90 and 99% for neutral and charged chemicals respectively were successfully achieved under the standard operating condition with only two exceptions (i.e. bisoprolol and carazolol rejections by the TFC-HR membrane). These lower rejections by the TFC-HR can be attributed to its highestwater permeability amongst the three membranes while both bisoprolol and carazolol are positively charged. Changes in operating conditions including permeate flux, feed temperature and chemical cleaning can exert a considerable impact on conductivity rejection by the three LPRO membranes investigated here. Feed temperature showed an apparent impact on the rejection of the selected organic chemicals. However, their rejections were still higher than the target validation values. The protocol developed here can be expanded for the validation of other organic chemicals.

Quantification and modelling of organic micropollutant removal by reverse osmosis (RO) drinking water treatment

“…The pH-dependent octanol-water distribution coefficient (log D OW ) was used to describe hydrophobicity. The compounds with log D (pH 7 ) ≥ 2 are referred to as hydrophobic and those with log D (pH 7 ) < 2 are hydrophilic [44,45]. Therefore, the compounds were categorized as: (1) neutral and hydrophobic (HP); (2) neutral and hydrophilic (HL); (3) anionic; (4) cationic.…”

“…5, all neutral HL MPs larger than 140 Da were highly or moderately removed (passage < 20%). For some compounds such as methenamine (44), gabapentin (31), metribuzin (46), pirimicarb (63), bisphenol S (13), phenobarbital (62), TCEP (71), pentoxifylline (54) and hydrochlorothiazide (35) the removal was high, and the passage was lower than 5%. This could be a result of steric and electrostatic exclusion.…”

Evaluation of reverse osmosis drinking water treatment of riverbank filtrate using bioanalytical tools and non-target screening

“…The molecular weight cut-off (MWCO) values for this membrane range between 100 and 200 Da. [51][52][53] It is noteworthy that RO membranes are considered non-porous and thus the MWCO principle may not be applicable since solute-membrane affinity interactions influence compound removal rather than only compound size. 13 Each step was equipped with flow meters to monitor the feed water, permeate and concentrate lines.…”

Online monitoring of N-nitrosodimethylamine for the removal assurance of 1,4-dioxane and other trace organic compounds by reverse osmosis

“…2 Among these advanced treatment 42 processes, RO is a critical physical barrier to remove trace organic compounds (TOrCs) such as disinfection by-products, endocrine disrupting compounds, and pharmaceuticals and personal care products that are ubiquitous in reclaimed wastewater. [3][4][5][6][7] Thus, monitoring the integrity of the RO process is essential during potable water reuse operation. In particular, much of the recent attention has been given towards two specific TOrCs namely N-47 nitrosodimethlyamine (NDMA) and 1,4-dioxane.…”