FR-RO Chosen as Key Technology for Santa Monica’s Desalination Plant

California is among the highest-risk states for droughts and water shortages due to climate change. Cities such as Santa Monica are turning to new technologies to increase water production and ensure a reliable supply for the future.


ROTEC specializes in the development and deployment of an advanced reverse osmosis technology (RO) that can be used to retrofit existing RO units to increase the recovery of water. The unique Flow Reversal Reverse Osmosis (FR-RO) technology is already in use at dozens of facilities around the world. However, the Arcadia water treatment plant is the largest municipal facility within the US and provides a direct source of 10.9 MGD of pure water for the people of Santa Monica. This is part of a project to achieve 99% water self-sufficiency instead of relying on 50% imported water as they did ten years ago.


alt removal in municipal water treatment has always been a challenge. The advent of reverse osmosis a few decades ago has made this practical. However, the water recovery rate is one of the most significant challenges, with conventional reverse osmosis systems only allowing the Arcadia plant to achieve a maximum of 82%. This means 18% of that hard-to-find water was thrown away. After retrofitting with FR-RO from ROTEC, the facility is achieving >90%, recovery, greatly reducing the amount of water that goes to waste. This means that for every 10 gallons of water treated, 9 gallons of drinking water will be produced instead of the 8 gallons of the previous system. This is critical because groundwater is a limited resource, and any waste of that valuable water makes self-sufficiency more challenging.

The unique flow-reversal of FR-RO systems makes this possible by reducing the effects of scaling that prevent traditional RO units from operating reliably at higher recoveries. FR-RO can also reduce biofouling, where bacteria might otherwise accumulate inside the system and cause operational challenges. Intermittent reversal of the flow within the RO system prevents excessive concentrations from forming within any individual section of the system, thus effectively “rotating the tires” to prevent scaling or fouling to build up on a particular spot.


The Santa Monica facility is far from being the only one adopting FR-RO technology. ROTEC is currently working with the Pure Water San Diego Program to install a demonstration system at the Point Loma Wastewater Treatment Plant to recycle 95% of the water that is currently being discharged to the ocean. Additional information on this project and comments by ROTEC USA CEO, Bruce Alderman can be found in this article by H2O global newsFlow Reversal technology evaluated for ambitious Pure Water San Diego program.