Two alternative chemical trains are being considered Train 1

Two alternative chemical trains are being considered. Train 1 includes three chemical processes, each of which, when operating normally, reduces the target pathogen by two orders of magnitude (a 2 log reduction). Train 2 includes four independent unit processes in series. Two of the processes reduce the target pathogen by two orders of magnitude. Each of the other two processes reduce the target pathogen by one order of magnitude (a 1 log reduction in each step). If each of the seven unit processes listed above fails to perform, at random, about one percent of the time and if, when a unit process fails, the removal it achieves is half of what it normally achieves.

Estimate:

(1). The overall removal for trains 1 and 2 when all the unit processes are operating normal.

(2). For each train the frequency (in days per year) of various levels of removal assuming that process failures occur randomly.

Solution