Backriver wastewater treatment plant must disinfect its effluent before discharging the wasterwater onto Backriver. The plant has plug flow reactor of length 1800m which treats the wastewater biologically by first order reaction with decay at a rate constant of 0.20h^-1. The wastewater influent has a linear velocity of 0.5m/s and contains 3.0x10^5 fecal coliform colony unit (CFU) per liter. Determine the coliform concentration of the discharge effluent into Back river.