Transport considerations for microbiological control in piping

Microbiological control in clean piping systems is limited by transport processes that distribute the disinfecting medium. The critical locations where transport resistance can be expected are the piping dead legs. Transport in dead legs was analyzed theoretically for two common disinfection methods: thermal; and ozone treatment. Established guidelines for clean piping design should not be universally applied. Specific guidelines for these different technologies are proposed. By differentiating between permanent and temporary dead legs, ozonated systems can be designed to be at least as reliable as thermal systems. Scale-up of thermal systems should include increasing the circulating velocity of the loop.