Question

A. Non-Texthook: Problem NT 4-3: 2 pts Given: A diffuser at the end of a 1.00 m diam., 9.00 km long ocean outfall pipe from the Hyperion Wastewater Treatment Plant (El Segundo, CA) discharges treated wastewater into the Pacific Ocean 7.20 km from Santa Monica beach. The wastewater contains 10 coliform bacteria per milliliter The wastewater discharge flow rate is 0.560 m/s. The coliform first-order death rates in the diffuser pipe and in seawater are 0.0500 h ' and 0.300 h 1, respectively. The current carries the wastewater plume toward the beach at a rate of 0.20 m/s. The ocean current may be approximated as a pipe carrying 600 m'ls of seawater. The physical system is the same one as described in textbook problem 4-30, except, parameter values have been modified and reaction in the outfall diffuser pipe is to be considered (in addition to reaction in the sea water). Required: The coliform concentration at the beach. Assume that the pipe and ocean current both behave as plug flow reactors and that the wastewater is completely mixed in the current at the discharge point. ns is not required. Define all variables used. 1) Reaction occurs in outfall pipe 2) Ideal mixing of wastewater and seawater in a small mixing zone at the outfall discharge point. 3) No coliform organisms are present in the seawater upstream of the mixing zone 4) Reaction in the mixing zone is small and can be neglected due to a short detention time. 5) Steady-state conditions Assume:

Answer 1