Reverse Osmosis Systems

Process description

Nanofiltration- (NF) and reverse osmosis- systems (RO) are used for production of process water, industrial water and drinking water, as well as in water recycling systems. The operating costs of these processes depend greatly on the pressure losses in the membrane modules. Therefore, not only are measures taken to avoid deposits on the membranes, but also tailor-made cleaning cycles are provided to remove deposits.

Gas application

CO₂-injection is used in both avoidance measures and in cleaning cycles:

• pH-adjustment of the inlet water prevents scale build-up on the membranes. Depending on further use, CO₂ is the acid of choice
• A rinse foaccording the CO₂-water flush process* cleans spirally wound membranes of organic deposits and particles. Water satured with CO₂ is used as rinsing water. The targeted degassing of CO₂ in the spacer channels leads to a significant increase in the rinsing turbulence and causes efficient removal of contamination from the spacers.

Advantages compared to chemical cleaning:

• Very short cleaning time: 5 minutes compared to 8 hours
• Higher cleaning efficiency for the spacers  
• Environment-friendly: the CO₂-footprint is reduced by up to 75 %
• Existing plants can be retrofitted  
• Low investment and operating costs

Messer solution

For membrane processes Messer provides

• Design of pH-adjustement and of the CO₂-saturated water preparation   
• CO₂-unit with supply tanks, evaporator, metering station and feed hardware
• CO₂ supply
• Support from our national and international experts

* The CO₂-water flush process is protected by patents belonging to Vitens and WE Consult (NL) and is marketed under license by RWB Water