A surrogate-based approach for trace organic chemical removal by a high-rejection reverse osmosis membrane

Takahiro Fujioka; Haruka Takeuchi; Hiroaki Tanaka; Hitoshi Kodamatani

doi:10.1016/j.scitotenv.2019.134002

A surrogate-based approach for trace organic chemical removal by a high-rejection reverse osmosis membrane

Sci Total Environ. 2019 Dec 15:696:134002. doi: 10.1016/j.scitotenv.2019.134002. Epub 2019 Aug 19.

Authors

Takahiro Fujioka¹, Haruka Takeuchi², Hiroaki Tanaka², Hitoshi Kodamatani³

Affiliations

¹ Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 85 2-8521, Japan. Electronic address: tfujioka@nagasaki-u.ac.jp.
² Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu 520-0811, Japan.
³ Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan.

PMID: 31470318
DOI: 10.1016/j.scitotenv.2019.134002

Abstract

Public confidence in the safety of recycled water for potable water reuse can be improved by providing assurance regarding high removal of trace organic chemicals (TOrCs) by reverse osmosis (RO) treatment. This pilot-scale study assessed the effectiveness of a surrogate indicator-N-Nitrosodimethlyamine (NDMA)-for ensuring a high level of TOrC removal by a high-rejection RO membrane. The pilot-scale tests showed that the rejection of 23 TOrCs by the high-rejection RO membrane was consistently greater than NDMA rejection. In addition, NDMA rejection was highly correlated with TOrC rejection across varied operating conditions, indicating that NDMA can be used as a conservative surrogate indicator for TOrC removal. The RO treatment at a permeate flux of 20 L/m² h and feed temperature of 13-27 °C resulted in as high as 75-87% NDMA rejection, which was considerably greater than a conventional low-pressure RO membrane (26-47%). However, the high-rejection RO membrane required a transmembrane pressure that was greater than that of the low-pressure RO membrane. Despite this disadvantage, this study suggests that the high-rejection RO membrane can effectively ensure a high level of TOrC removal (≥65%) when NDMA is used as a surrogate indicator, which cannot be ensured by assessing conventional conductivity rejection.

Keywords: CECs; Micropollutants; NDMA; Potable reuse; RO membrane; TOrCs.