The kill of pathogens by disinfection in water treatment can be described by a first order reaction. Complete a reactor comparison for a batch reactor, CSTR and PFR for disinfection. The treatment plant produces 100 L/s of water. The starting concentration of pathogens is 20,000 organisms/L and the desired final concentration is 5 organisms/L. The reaction rate constant is 0.05 per second.
a) Determine the volume of reactor needed for each hydraulic regime.
b) From the volume, calculate a possible L x W x H for each tank. Are the tanks sizes reasonable?
c) Which design would you choose and why? (For the batch system, assume one batch reactor is filling while the other is reacting).