Disinfection by ozone follows first-order kinetics, with a rate constant of 1.2/minute. The town of Obfisquitory wishes to use 4 equal volumes of CFSTR's in series to disinfect 2 million gallons per day (mgd) of water containing 1000 coliforms/L to the maximum required concentration (MCL) of 1 coliform/L.
a) Determine the volume of each CFSTR
b) If a two CFSTR, with a volume equal to the sum of the four in series, is used for disinfection, what will the final coliform concentration be?