An ocean outfall diffuser that discharges treated wastewater into the Indian Ocean is 5,000 m from a public beach. The wastewater contains 105 coliform bacteria per milliliter. The wastewater discharge flow rate is 0.3 m3/s. The coliform first-order death rate in seawater is approximated 0.3 h-1. The current carries the wastewater plume toward the beach at a rate of 0.5 m/s. The ocean current may be approximated as a pipe carrying 600 m3/s of seawater. Assume that the current behaves as a plug-flow reactor and that the wastewater is completely mixed in the current at the discharge point.
Determine the coliform concentration at the beach. (assume that the current behaves as a plug flow reactor and that the wastewater is completely mixed in the current at the discharge point.