As a waste moves downstream, exertion of the oxygen demand removes oxygen from the water and exchange with the air (reaeration) adds oxygen to the water. Initially exertion exceeds reaeration and the dissolved-oxygen (DO) content of the water drops. Later, as the waste becomes stabilized (no longer consuming as much oxygen), the river DO increases. The result is a dissolved-oxygen sag curve. Equations were provided in this chapter to determine the location and value for the minimum point in the DO sag curve. Using data from Problem 5-10 and assuming that there is no NBOD exertion, calculate the oxygen deficit (Do) in the river after it has mixed completely with the waste discharge, the time and location of the maximum deficit, and the minimum DO concentration. Assume a saturation DO for the river of 10 mg/L, that k, = /Q., and that the reaeration coefficient (k2) is 0.3 day'.