In Professor John Katers’ Pollution Control class, a trip to Wisconsin’s largest family-owned dairy, Pagel’s Ponderosa in Kewaunee County, provided a true 360° learning opportunity. This large operation has approximately 4,700 cows in their milk production system and, as can be imagined, the cow manure coming from this herd could potentially be, well, overpowering. And in a sense it is, but not in terms of odor generation.
Rather, the farm uses a sophisticated, engineered system that collects the manure and feeds it to an anaerobic biodigester. The biodigester uses the methane gas produced to power a 20 cylinder Caterpillar engine which drives a generator that sends electricity out to the grid. The cows and the biodigester system have a 1,100 KwH production capacity which is enough to provide all of the electricity for the villages of Luxembourg and Casco, or approximately 800 homes for a year.
The by-product of the biodigester is a bio-solid which has a somewhat fluffy texture and very little smell. This product is reused in the barns as a bedding product for the cows and as a land application on the fields where crops are grown to feed the herd. A benefit from this type of biodigester system is that the methane, a potent greenhouse gas, is consumed in generating the electricity rather than emitted to the atmosphere.
In addition to seeing the milking operation and the rotary milking parlor, where cows willing and calmly load themselves onto a rotating carousel for the milking process, students also visited the calf barns where the next generation of dairy cows-to-be begin their growing out process.
The 36,000 gallons of milk produced daily at Pagel’s Ponderosa (that’s six 6,000 gallon tankers) goes to Saputo’s for processing into mozzarella and provolone cheese used in the pizza production industry. For the students, who are known to eat a few pizzas in their years at college, that’s a true 360° learning experience.
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