Effect of pre-ozonation on nanofiltration membrane fouling during water reuse applications

Hooman Vatankhah, Conner C. Murray, Jacob W. Brannum, Johan Vanneste, Christopher Bellona

Index: 10.1016/j.seppur.2018.03.052

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Abstract

The selection of appropriate purification technologies for the potable reuse of municipal wastewater effluent is an important component of water resource management. In this study, a fully automated high-pressure bench-scale membrane system was used to investigate the impact of pre-ozonation of wastewater effluent on nanofiltration (NF) fouling during reuse applications. A commercial polyamide NF membrane was employed to evaluate the impact of pre-ozonation on fouling and determine an effective specific ozone dose. The results indicated that pre-ozonation of sequencing batch reactor membrane bioreactor (SBMBR) effluent with a relatively low specific ozone dose (0.2 mg O3/mg DOC) could effectively mitigate a significant portion of fouling on the membrane compared to filtration without pre-ozonation. However, increasing the specific ozone dose to 0.4 mg O3/mg DOC did not provide a significant additional benefit. The dissolved organic carbon removal performance of the NF membrane did not show a substantial change when pre-ozonation was applied and remained relatively constant which may be due to the relatively low applied specific ozone dose. Organic fouling was suspected to be the main fouling mechanism during SBMBR filtration with NF membrane based on characterization methods applied during the study.