Question

Let’s consider a portable UV disinfection system to be used with 5-gallon (18.9 L) coolers with a modified lid. The setup will allow water to flow into the top and out a spigot at the bottom. The resulting contactor is effectively a CSTR.

1. 1. If the disinfection rate constant for UV₂₇₈ is 6.3 s^-1 for E. coli, what is the maximum flow rate that the system can handle to achieve 99 percent inactivation? (answer in L/min)
2. 2. If you decide to operate the device in batches instead of in a flow-through mode, how long should you wait to achieve 4-log inactivation of E. coli? (answer in min)

Answer 1