Sizing of a Discharge Tank

by Matthew Roche

Submitted : Fall 2008

To solve this problem you break it into two parts. First you find the size of the tank. To find the tank size you first set up an equation relating the concentrations of ammonia into the tank and out along with the flow of that mix in and out. You integrate the equation and solve for the volume to get the total size of the tank. To find the time above 80 ppm you have to set up an exponential equation. You get the equation relating tank size with flow into the tank and out. Then integrates and find the time at 80 ppm. You end up getting a tank size of at least 4481L. The tank should be at least that but would be better off being larger than that. The fish in the river will be exposed to the ammonia above 80 ppm for about 2.28 minutes. It takes about 20 min for the tank to get back to 50 ppm and is ready for another spike of ammonia.

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