Field Studies on an Anaerobic Lagoon
Treating Slaughterhouse Waste
KEITH E. ENDERS, Engineer
U. S. Public Health Service
Shiprock, New Mexico
MARK J. HAMMER, Associate Professor
University of Nebraska
Lincoln, Nebraska
CLINTON L. WEBER, Engineer
Kirkham, Michael & Associates
Omaha, Nebraska
INTRODUCTION
These studies were performed on anaerobic lagoon waste treatment units located in the rural countryside of northeast Nebraska. This abattoir slaughters beef
cattle and ships the processed beef as dressed halves. Cattle are trucked in daily
for slaughtering, and the processed beef is stored under refrigeration until shipped.
The wastes originate from the holding yard, the slaughtering floor, the gut and
hide processing units, the plant domestic facilities, the clean up operations, and
the cooling water.
When an animal is stuck and bled, the whole blood is collected for processing.
The hides are washed, salt-cured and stored for resale. The paunch manure is
removed by fine screening of the segregated waste stream from the paunch cleaning unit. In addition to paunch manure and whole blood, certain materials in the
gut processing are also recovered. The process wastes from slaughtering and gut
processing flow through a skimming tank. The tank skimmings and other process
waste trimmings, including bones, are rendered for recovery of inedible byproducts.
The process waste waters, after removal of edible and inedible by-product,
are merged with the surface drainage from the holding yard and the cooling water.
This combined waste flow is pumped to the lagoon treatment system consisting of
first-stage anaerobic lagoons, followed by intermediate and secondary aerobic
lagoons.
ANAEROBIC LAGOON SYSTEM
A schematic of the anaerobic lagoon system is shown in Figure 1. The two
lagoon cells are operated in parallel with one-half of the raw influent going to
each cell. The effluent from the anaerobic cells flows into an aerobic lagoon
system for further treatment. The anaerobic lagoon inlets are spaced across the
bottom of the lagoons at one end and the outlets are at the opposite end submerged two ft below the liquid operating surface.
The criteria for the original design of the anaerobic lagoons were the following:
Beef kill, number per operational day    400 head
Average flow, daily operation 410, 000 gal
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