Document Type


Publication Date



Bioresource and Agricultural Engineering | Industrial Technology

Course Number and Title

TSM 416: Technology Capstone


Agricultural and Biosystems Engineering


Agricultural Systems Technology (Kvistad, Raver, Oeltjenbruns)


Michael Anderson and Jacek A. Koziel

Problem Statement

Smithfield Hog Production has processing facilities throughout the state of Iowa as well as contract finishing sites where producers grow out their swine. The hog manure from these sites is pumped into a slurry store for storage until it can be pumped onto the fields in the spring or fall. The slurry stores stand 19-feet-tall, have a diameter of 120-feet, and hold 1.2-million-gallons of manure. The slurry stores have no cover so they are open to all weather like rain and snow.

Most years, evaporation does not equal precipitation which results in a decreased manure holding capacity and an increased cost to pump the manure. The precipitation that accumulates in the tank also lowers the per gallon value of the nutrients as a crop fertilizer due to dilution. A cover for the slurry tanks would eliminate precipitation from entering the tank.