What to Do About Paunch Wastes
A. J. Steffen
Sanitary Engineer, Wilson and Company, Inc.
Chicago, Illinois
The meat-packing industry has long known the value of meat byproducts. These by-products, including animal feeds, pharmaceuticals,
leather goods, and fertilizers, represent a large portion of the salable
product of the industry.
Concentration of the packing industry in some of the large population centers focused the attention of municipal sewage-treatment officials
on meat packing wastes years ago. This stimulated interest in byproduct recovery to a point where practically all the parts of the animal
are used and only wash water and a limited amount of process water
now enter the sewers.
The size of the packing establishment determines, to some degree,
the extent of by-product recovery practiced. Small packing plants
obviously can not accumulate enough of some of the by-products to
warrant recovery; thus, a small country slaughterhouse will discharge
blood and slime into the sewers where the large packer will carefully
save these valuable by-products. In the larger plants all recoverable
proteins and fats are utilized.
In some cases, wastes are recovered or segregated with no possibility
for economic utilization. Paunch wastes are in this category. Before
passing on to treatment methods for paunch wastes, it is important
that these materials be defined.
The paunch or rumen or, if you like, the first stomach of a cow,
steer, bull, heifer, calf, or sheep and other ruminants contains the stored
food matter ingested by the animal before it passes into the rest of the
complicated digestive system. The next organs of digestion are, in turn,
the honeycomb or second stomach, the peck or third stomach, and the
rennet bag or fourth stomach. The concern here is with the contents of
the storage stomach or paunch. Active fermentation takes place at this
point, caused by many different kinds of highly active micro-organisms.
The paunch content of cattle is estimated at 40 to 60 pounds per head
and of sheep from 20 to 30 pounds per head. It contains undigested hay,
straw, corn, and grain and has an acrid odor. The undiluted material is
rather light in weight, ranging from 40 to 50 pounds per cubic foot.  In
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