Discussion of "Oxygen Sag Models for Multiorder Biochemical Oxygen Demand Reactions" by Donald Dean Adrian, Emerald M. Roider, and Thomas G. Sanders

Samples are collected in a river at various locations downstream of a discharge source. The samples are returned to the laboratory where standard BOD tests are run, usually long enough to determine the ultimate BOD of each sample. These are the bottle BOD results. These bottle BODs are then plotted against travel time in the river, based on the time it takes for material to arrive at each sampling point from the discharge point. This is a function of distance downstream from the discharge and the average velocity in the river. The river loss rate is now determined based on this data by plotting the natural log of the bottle BODs versus travel time. It should also be noted that the river loss rate is also determined at the ambient temperature in the river, even though the bottle rates are always determined at 20 DG C.