English Arabic Chinese (Simplified) French German Greek Italian Polish Portuguese Russian Spanish
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • +44 (0) 161 877 2334

Reverse Osmosis Plant - Improving RO Membrane Efficiency

Reverse Osmosis Plant - Improving RO Membrane Efficiency

This short paper briefly reviews some of the common problems faced by operators of Reverse Osmosis plant installations and looks at ways of overcoming these issues with the aim of improving operational efficiency, water quality and reducing life-cycle costs.

The paper summarises common RO related problems and reviews the need for suitable, but simple treatments that can be used to combat them these issues.

Reverse Osmosis Membranes

All Reverse Osmosis plant installations have at their heart an RO membrane that is essential to the efficient operation of the system.

If the membrane becomes damaged in any way it can lead to reduced output, increased operational costs and poor water quality.

It is therefore vital to keep the membrane protected, clean and free of contaminants and so operating at optimum efficiency.

RO Membrane Composition

Most RO membranes are formed from hollow fibre or thin film composite sheets with the membrane allowing the passage of purified water through the membrane and the rejection of any dissolved solids or contaminants contained in the feed water.

Membrane Contamination

As the raw water passes along the membrane surface the solids concentration increases and some sparingly soluble salts begin to exceed their solubility and precipitate.

When precipitated onto the membrane surface these salts result in fouling which can lead to reduced output and increase water conductivity.

Calcium Carbonate and Calcium Sulphate

The most problematic of these solid membrane contaminants are calcium carbonate and calcium sulphate and so the prevention of their precipitation is vital if the membrane is to function efficiently.

Traditionally, the method used to prevent the precipitation of calcium carbonate and calcium sulphate on the RO membrane was to pre-treat, to “de-alkalise” the feed water using sulphuric acid and so prevent calcium carbonate precipitation.

However sulphuric acid is hazardous, increases the sulphate concentration and also increases the corrosivity of the water on both sides of the membrane.

This caused a reduction in the recovery rate of the RO plant, eliminated calcium sulphate precipitation but also reduced the efficiency of the plant and hence increased operating costs.

RO Membrane Antiscalants

To overcome these problems and improve plant efficiency the technical specialists at Accepta recommended that a suitable RO membrane antiscalant is employed.

Suitable membrane antiscalants should have the following characteristics:

  • Safe to handle and safe to use
  • Good scale prevention
  • Membrane compatible
  • Effective across a wide pH range
  • Compatible with other RO products
  • Cost effective

Residual Iron Levels

It is also normal operating practice to ensure residual iron levels in the RO feed water are kept as low as possible, normally below a maximum set by the membrane manufacturers.

Precipitated iron is a membrane foulant and adversely affects the performance of many membrane scale inhibitors.

With this in mind it is important to design chemical and reverse osmosis maintenance programs that are capable of meeting all of the above to ensure optimum plant performance and problem free operation.

Additional information

For additional information, expert advice, application procedures and Safety Data information relating to our range of reverse osmosis membrane treatment chemicals please contact Accepta's technical support specialists on +44 (0) 161 877 2334 or email This email address is being protected from spambots. You need JavaScript enabled to view it. .

World Class Expertise

Accepta work with industry worldwide delivering practical, cost effective solutions to resolve complex problems. If you require technical assistance, or information about our water treatment chemicals and other speciality products, please contact our dedicated technical support team on:

+44 (0) 845 519 89 90 or complete our Technical Support form.

Expert Training

Develop your skills with our internationally recognised water and wastewater treatment training courses. Delivered by world leading industry experts and designed for engineers, facilities managers and environmental professionals... water treatment training.

Keep upto date with our extensive library of good practice guides, latest research, regulatory updates, news and more... knowledge base.

Custom Chemical Manufacturing

Accepta offer custom chemical manufacturing, specialist toll blending and white label production services for our own water treatment chemicals and client specific formulations to UK and international customers.

To discover how you could benefit from our environmentally sensitive, quality driven chemical manufacturing capabilities please call us on +44 (0) 161 877 2334 or contact us.

International Distributor Opportunities

Accepta's innovative, quality driven customer focused business model creates exciting global supply chain and distributor opportunities for established and ambitious businesses currently active within the water treatment, wastewater treatment and environmental services sectors around the world.

If you are interested in becoming an exclusive international distributor of Accepta water treatment technologies please click here to learn more.

bsi-ukas-14001-2004bsi-ukas-9001-2008british-association-for-chemical-specialitiesinvestors-in-people-iip  greater-manchester-chamber-of-commerce-member