On‐Site Evaluation of Electropositive Filtration for Fouling Control: Case Study in a Water Reuse Desalination System

ABSTRACT

Cartridge filters are used as a prefilter to reverse osmosis (RO) membranes to reduce membrane fouling during operation. However, cartridge filters typically serve as a physical barrier for foulant removal. This study reports a side‐by‐side comparison of an electropositive filtration (EPF) cartridge (NanoCeram) with a conventional string‐wound filtration (SWF) under full‐scale operating conditions at the Scottsdale Water Reclamation Facility (Scottsdale Water Campus). A customized two‐stage RO test bed operating at 500 gal per day and 25%–40% recovery was used to evaluate the performance of EPF over an 8‐week period. Performance metrics included RO permeate flux stability, membrane fouling analysis, and specific energy consumption of water production. The EPF filter was found to reduce membrane fouling, resulting in a ~20% increase in RO permeate flux and 13%–18% decrease in energy consumption in the unit operating with the EPF compared to the one using the conventional SWF. In addition, the presence of a carbon filter prior to the EPF filter was found not to be needed for its good operation. This study is the first report of an on‐site trial of EPF cartridge filters for RO fouling mitigation in a wastewater reuse setting.