The advancement of membrane processes over the past ten years has resulted in an economically viable drinking water treatment solution for both large- and small-scale applications. The following shows the typical applications of various filtration methods.
Households
Rainwater can be collected from storm drains and be purified with reverse osmosis water processors. This water can then be used for landscape irrigation and industrial cooling.
Power Plants
Reverse osmosis removes minerals from boiler water at power plants to ensure that the water doesn’t cause corrosion or damage to the machinery, which would reduce efficiency. Moreover, reverse osmosis plant membrane systems typically use less energy than thermal distillation.
Reverse osmosis is also used to clean effluent and brackish groundwater. The effluent in larger volumes (more than 500 cu. meters per day) should be treated in an effluent treatment plant first, and then the clear effluent is subjected to reverse osmosis system. Treatment cost is reduced significantly and membrane life of the RO system is increased.
Medical Industry
Reverse osmosis is similar to the technique used in dialysis, which is used to treat renal kidney failure. The kidneys filter the blood, removing waste products (e.g. urea) and water, which is then excreted as urine. A dialysis machine mimics the function of the kidneys. The blood passes from the body via a catheter to the dialysis machine, across a filter that removes the wastes, and then reinters the body.
Food & Beverage Industry
In addition to desalination, reverse osmosis is a more economical operation for concentrating food liquids (such as fruit juices) than conventional heat-treatment processes. Its advantages include a lower operating cost and the ability to avoid heat-treatment processes, making it suitable for heat-sensitive substances like the protein and enzymes found in most food products.
Dairy Farming
Reverse osmosis is extensively used in the dairy industry for the production of whey protein powders and for the concentration of milk in order to reduce shipping costs. In whey applications, the whey (liquid remaining after cheese manufacture) is concentrated with reverse osmosis from 6% total solids to 10-20% total solids before UF (ultrafiltration) processing. The UF retentate can then be used to make various whey powders, including whey protein isolate used in bodybuilding formulations. Additionally, the UF permeate, which contains lactose, is concentrated by RO from 5% total solids to 18–22% total solids to reduce crystallization and drying costs of the lactose powder.
Car Washing
Because of its lower mineral content, reverse osmosis water is often used in car washes during the final vehicle rinse to prevent water spotting on the vehicle. Reverse osmosis water displaces the mineral-heavy reclamation water (municipal water). Reverse osmosis water also enables the car wash operators to reduce the demands on the vehicle drying equipment, such as air blowers.
