Combat

There is no PW or WFI water gener­a­tion and distri­b­u­tion system that is sterile over the whole life­cycle. Microor­gan­isms always find a way into the plant. Either through the raw water, or during main­te­nance activ­i­ties et cetera. Sterility is tech­ni­callynot achiev­able and would generate a high effort and cost. 

Frequent sani­ti­za­tion procedures reduces the life­time of some compo­nents or even worse may result in malfunc­tion like membrane damage in a reverse osmosis which would reduce the barrier effect for microor­gan­isms and thus result in a higher bioburden of the water after this purifi­ca­tion step. The goal is not to achieve a sterile system but to keep the bioburden below specific limits. The limits are defined for the final product e.g. for WFI the limit is 10 CFU / 100ml, but there are no limits defined after each purifi­ca­tion step. As part of a cont­a­m­i­na­tion control strategy, it’s more and more impor­tant to not only prove the quality of the final product, but also to show that each step of the water purifi­ca­tion process is working within its spec­i­fied para­me­ters.