Piloting experience of ROTEC's flow reversal RO (FRRO) for 90 % recovery in brackish water desalination

This work reports piloting data analysis of ROTEC's flow reversal RO (FRRO) at City of Santa Monica's Arcadia Water Treatment Plant. It is shown that periodic block rotation and feed flow reversal balance salt and foulant load and mitigate scaling formation, enabling a 90 % recovery with a typical CIP interval over 30 days. As membrane fouls, there is a decline in the specific flux and an increase in the specific pressure drop. Nevertheless, the last stage pressure is usually no more than 200 psi. The successful pilot led to the design and commissioning of the first FRRO full-scale municipal installation in the United States. •Pilot study of flow reversal for ultra-high recovery RO using real water was reported.•Pilot data were analyzed including specific flux, specific pressure drop and SEC.•Concentration overshoot during flow reversal was discussed.•Full-scale retrofit based on pilot study was discussed.