A paper by Lott et al. addresses the design of feedlot manure settling systems in Australia. In a series of experiments they derive settling velocity distributions for cattle manure from several sources (their Table 5).
1) Using Stokes' law for gravitational settling, calculate settling velocities from the following table:
Table 1. Physical Properties of Beef Cattle Feedlot Manure.
2) How do your results compare with those of Lott et al. ?
3) What is the total TS removal you would expect from a beef cattle feedlot setting basin 1 meter deep, with a surface area of 100 square meters, during a runoff event whose flow is 10 cubic meters per minute? Be sure to show your calculations and state any assumptions.
4) Identify and discuss 3 aspects of the experimental design, methods, or analysis of Lott et al. which may have biased the results reported in their paper.
Solution (you can download this MS Excel spreadsheet on discrete settling to your computer).