Reverse Osmosis

July 27, 2009

The process of Reverse Osmosis and what are the benefits to us?

Simply put, the Reverse Osmosis (RO) solution is an extremely successful way of demineralizing water by moving it through a fine ‘RO membrane’ under pressure, leaving the impurities and contaminants on one side and the ‘purified’ water on the other. The pressure exerted during the process depends upon the type of water being treated, be it fresh or salt water, the concentration of contaminants and impurities etc. In fact, the process originated in the conversion of salt water into fresh water but has many other uses in industry, medicine and around the house.

There are many filtration systems used across the globe to purify or improve our drinking water and the RO system is just one.

RO systems typically comprise a number of important steps to ensure success. The water to be treated first needs to be filtered to clean it of larger particles such as rust from pipes and calcium. It can then be filtered again through active carbon to reduce the level of smaller particles such as chemicals or chlorine. This can be important depending on where the RO unit is operating as some of these chemicals can over time ruin the RO membranes. The water is then passed through the RO membrane with the option of then additional carbon filters and even UV light to make sure that all chemicals and microbes are removed. This invariably depends on the end use of the water, how pure the requirement and what the final chemistry of the water needs to be. The RO filters used are typically able to remove contaminant particles that are larger than 0.1nm in size and these filter fall into the finest filtration category of ‘Hyper-filtration’.

In countries where there is a poor or polluted water supply or where people are living out in the middle of nowhere, portable reverse osmosis systems can be used. Water from rivers, lakes and even the sea (desalination) can be treated using these units.

The US military use a reverse osmosis system extensively during training exercises and on the battlefield. Their ROWPUs or ‘reverse osmosis water purification units’, can produce huge amounts of purified water for the troops and a single unit can in fact provide enough for up to 6,000 men and women.

The Ro systems are extensively used worldwide in a diverse number of situations, from purifying rainwater for crop irrigation and industrial use where water shortages are common to purifying water used in power stations where purity is essential and in medicine where similar systems are used in the treatment of patients with kidney problems who need deionized water for dialysis machines. Our food and dairy industries also use huge amounts of purified water treated by reverse osmosis systems in the production of fruit juice, whey powders, milk concentrates and other heat sensitive products. RO is a more cost effective way of purifying water to be used in food production, rather than processes involving heat treatment. Even the wine growers of France who have historically frowned upon the use of RO water are utilizing the systems.

The disadvantages of RO in a household environment are in the main that the process is very wasteful, when the systems just cannot generate enough pressure and as a result, they are only about 10% efficient as opposed to industrial grade systems which approach 50% efficiency. Apart from this the demineralization process leaves the water too acidic which in turn can leach essential minerals from our bodies when we drink it, creating problems for bone,s organs and teeth. It is therefore essential for our health that some form of mineral intake is used to supplement purified water generated by RO systems.

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The Good and Bad of Reverse Osmosis

Although reverse osmosis can be a valuable water purification process when mineral-free water is required, removing the alkaline mineral constituents of water produces an acidic water which can be very dangerous to the human body, causing calcium and other essential minerals to be stripped from bones and teeth. For more information….