The Industrial Water Purification Blog

Why Reverse Osmosis Water Treatment Systems Fail And How To Ensure Yours Doesn't

Posted by Peter Wood on 29-Sep-2017 10:25:33

Why Reverse Osmosis Water Treatment Systems Fail And How To Ensure Yours Doesn't.jpg

Reverse osmosis systems are used in many facilities that need a non-chemical means of purifying their water. These efficient systems employ semi-permeable membranes to filter out contaminants. RO systems can also remove organic contaminants and bacteria, as well as larger-sized viruses, thanks to the physical barrier the membrane provides.

However, just like any other system, reverse osmosis water treatment systems can and do fail. The failure of an RO system can occur for a number of reasons, but each type of failure is completely preventable.

Feed Water Pre Treatment

Quality pre treatment of the feed water to any RO plant is of the utmost importance. Granular activated carbon is used to remove free chlorine and organic matter. Feed water hardness must be reduced to < 4ppm CaC03 A feed water filtration regime must be adopted with quality depth filters to

Growth Of Bacteria

Bacteria is a common threat to reverse osmosis purification systems, because it is already present in water. Contamination of an industrial RO system by bacteria usually occurs as the result of insufficient system disinfection. However, there are also a host of other ways that bacteria can thrive in RO systems.

Water Flow

The flow of water through the system is a vital part of ensuring that no bacterial colonies are able to grow in the system. When system-wide water velocity is inadequate, the water in some areas can become stagnant. This standing water is an ideal place for bacteria to thrive.


Long periods of time between regeneration can cause membranes to become fouled. This can also encourage bacterial growth. Often, the reason that membranes become vulnerable in the first place is because of the improper or insufficient pre-treatment of feed water to remove chlorine. The chlorine then passes through to RO membranes, which become weakened and physically damaged. Areas where the membrane has lifted or torn can become a haven for bacteria.


Bacteria can also grow in systems whose temperatures have dropped below 20°C. Left unchecked, a complete system shut down is the only way to ensure complete and proper disinfection.

Irregular System Disinfection

Many operators neglect to disinfect their RO systems. This is another major cause of bacteria entering the system. There are many benefits to regular disinfection. It takes far less time to routinely disinfect an RO system than it would to shut the system down and bring in professionals for microbiological testing.

It also costs far less to disinfect systems on a regular basis; instead of paying employees to wait until the system has been flushed and disinfected, business can continue as usual. Finally, in terms of chemicals or other solutions, regular disinfection requires far smaller volumes than do established bacterial infections.

Ensuring Continuous Operation

There are several ways to prevent the growth of bacteria and combat the irregular disinfection of RO systems.

Hydrogen Peroxide And Heat

Most forms of bacteria can be eliminated with regular hydrogen peroxide treatments. Peroxide will not harm RO membranes, and will not add any harmful chemicals to the water.

Heat can be another effective means of preventing bacterial growth. Regular heat sanitisation can be accomplished very quickly, whether doing it to eliminate established bacteria growth or for routine system disinfection. However, before using this method, it’s important to ensure your system is able to handle this sort of treatment.


Industrial RO systems can also benefit from regular disinfection using ultraviolet sterilisation. This solution is not only completely chemical-free, but is able to destroy most types of bacteria when the right intensity is used.

Adequate Monitoring

Regular plant monitoring can prevent your RO system from losing efficiency or developing faults. Although this will take time to accomplish, it is nothing compared to that required for complete system shut-down. Important elements of adequate monitoring include ensuring that every inspection is logged in terms of system data obtained, time and date.

Over time, these logs will provide a detailed and valuable history of your system’s operation, which can greatly assist personnel with gauging the possibility of future repairs or replacements.

Our Guide Will Help Keep Your RO System Healthy

Where it comes to the continued operation of your RO system, there is no substitute for professional advice. Our team at Wychwood have developed a resource that lets you access our wealth of knowledge at no cost. Our Complete Guide to Industrial Water Purification contains all you need to know to prevent bacteria, poor plant monitoring and inadequate maintenance from putting your industrial RO system out of commission. You can claim your instant download now, or, if you want to contact our team directly, simply email

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Topics: Reverse Osmosis

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