Methane generated from dairy manure through anaerobic
digestion is being used on large Midwest livestock farms to
make electricity. Methane can also be collected from
municipal solid waste and food processing sludge. And at
least two Minnesota cities are interested in producing
biogas from manure or food waste.
ANIMAL PROCESSING REMAINS
Composted critters
Composted livestock makes great fertilizer and soil
amendments. A St. Cloud, Minn., company makes humus, potting
soil and other garden products from composted poultry
processing waste and yard waste. An Alexandria, Minn.,
company is making phosphorus-free turf grass fertilizer from
liquefied fish and distillers grains. A commercial tilapia
farm in Renville, Minn., composts dead fish for fertilizer.
Offal-ly powerful
About 60 percent of a live animal’s weight is meat cuts.
Everything else — skin, bones, fat, organs, blood, trimmings
— is coproduct used by rendering companies, pet food
manufacturers and the leather industry. Rendered animal fat
can also be used to make biodiesel fuel. AURI has helped
small meat processors market their coproducts collectively,
so nothing is wasted.
Greasy fuel
Recycled yellow and white greases, beef tallow and chicken
fat can be burned for boiler fuel or processed for biodiesel.
Garden wool
Short wool fibers trimmed from blankets are being used to
make landscaping fabric for commercial strawberry growers.
Fluff food
Feathers, a byproduct of livestock rendering, are powdered
for livestock feed.
DAIRY
Whey, a watery leftover from cheese making, used to be
treated as sewage. Now, it’s being made into protein
concentrate and added to bakery products, infant formulas,
candy and energy bars. In the future, whey may be used for
oxygen-barrier coatings on food and plastics, and even to
make ethanol.
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