Pharmaceutical Water/USP 24 Purified Water

For USP 24 Purified Water, reverse osmosis is used to remove chemicals but requires an additional water treatment step for disinfection. In practice, reverse osmosis membranes allow a fraction of living bacteria to pass through minor imperfections, or bypass the membranes entirely through tiny leaks in the surrounding seals. In European countries reverse osmosis is not allowed under European law for treating natural mineral water. Dissolved ozone is preferred over chlorine, bromide and other sanitizers simply because ozone does not leave disinfection byproducts in water. Commonly, purified water is ozonated to 0.5 ppm to ensure microbiological purity and then the ozonated water is treated with UV lights to destroy the ozone before the water goes into any products.