Bacterial Growth In Ro Water

Bacterial Growth In RO Water

Reverse Osmosis (RO) is a process of water treatment that forces water under pressure through a semi permeable membrane to filter out most dissolved minerals. The objective is to produce high-quality pure water.

Every liter of pure processed water requires approximately 3 to 20 liters of impure water to be flushed away. Flushing helps in keeping the filtration membrane clean. The best type of bacterial resistant membrane is thin film composite, with cellulose triacetate coming next.

Purity of water is defined by two elements; the 'reject ratio' of the membrane, and the level of salts in the solution.  For instance, a 95 percent reject ratio means that 5 percent of the salt concentration has leaked through. The rejection ratio of processed water should be as high as possible and certainly in excess of 92 percent. With a thin film membrane, a rejection ratio of as high as 98 percent is achievable. Using this technology, the cost of water purification is understandably high. Pure RO water should not be stored in a holding tank for a long period of time as RO water contains no chlorine and therefore bacterial growth will occur.

Membranes used in the Reverse Osmosis process are susceptible to fouling and clogging because of hard water scale, bacterial slime, silt and iron. As far as possible bacteria contaminated water should first be treated or avoided.  Hard water more than 50 ppm, if being used as feed water, should first be softened and iron and sediment filtered out.  Some clogged membranes can also be chemically cleaned. A clogged membrane compromises the purity of the water and encourages rapid bacterial proliferation.

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Bacterial Growth In Ro Water