Reverse Osmosis Facts & RO Water Information

Technological advancements continually reshape many aspects of our lives. At a minimum, their promise is to make equipment or devices easier to use, more reliable and more efficient. However, there are still sleepy, rare sectors that managed to elude the influence.

Reverse Osmosis is undoubtedly one of them. While seeing several incremental improvements since its academic inception in 1959 and its piloting in the 1960s, modern reverse osmosis (RO) has largely remained in a technological comma – eking out small bumps in efficiency through membrane evolution and adding stages in series. In fact, many of the contemporary RO systems sold today by the big water companies have been designed in the 1980s and haven’t changed much since.  Even  “brand  new”  designs are based on the same old schemes and design principles of that bygone era. While we have seen some significant developments since the modern Reverse Osmosis (RO) membranes were developed in 1959 by Sidney Loeb and Srinivasa Sourirajan at UCLA using a cellulose acetate polymer, there have not been a great deal.

An event, certainly worth mentioning, is when DuPont patented its Permasep RO element based on an innovative polyamide chemistry in 1969. This was the first commercial reverse osmosis membrane for treating brackish water vs seawater and had a significant impact on industrial water treatment. Over the next two decades, perhaps the next most notable enhancement was the adoption of isobaric energy recovery devices in the industry. These devices enabled seawater reverse osmosis plants to cut their energy consumption and costs as more of the energy in the pressurized waste brine could be captured and used to power feedwater pumps. Overall, these improvements added up with energy costs in 2010 at around 1/5 and operating costs at 1/10 of what they were in the 1970s - incremental yet it was a giant leap forward for the industry.

Nearly 20 years later (after very little innovation), a new reverse osmosis process called Closed Circuit Reverse Osmosis (CCRO) was released in 2009. Instead of operating under steady state conditions where membranes are under constant attack by concentrated scalants and other foulants, membranes in CCRO are operated mostly in batch mode with an internal re-circulation loop and a flushing out of contaminants every half an hour or so. This offers complete control over the process and treats each membrane equally allowing for large improvements in recovery, fouling and scaling resistance and overall operations. 

With reverse osmosis systems often lasting 20 years or more, the purchase decision will impact a company’s performance and bottom line for decades to come.