Treatment of Waste From Small
Slaughterhouses
R. RUPERT KOUNTZ
Professor of Sanitary Engineering
The Pennsylvania State University
State College, Pennsylvania
When stream pollution must be abated cheaply and simply the
treatment of the waste from small slaughterhouses operating regularly
or intermittently poses a special problem in contrast to the large complete meat plant with processing and rendering. Realizing this problem the Sanitary Water Board appropriated $15,000 in February, 1947,
for the development of suitable treatment methods by The Pennsylvania State University's College of Engineering and Architecture.
Assistance from the State Department of Health in the form of a
staff Sanitary Engineer and a mobile field laboratory aided greatly
in the pursuit of this work. Construction of the pilot plant was started
in the summer of 1947 and the experimental work completed in
August, 1950, with the formal report being assembled and published
in January, 1953.
Biological methods if used for treating wastes from small slaughterhouses must be simple to operate and low in maintenance as the treatment plant operation will always be secondary to the butchering of
meat. The activated sludge process immediately is eliminated because
of the controls needed in operation, and also because of the nuisance
of excessive foaming due to the high protein content. It is debatable
as to how well a satisfactory floe could be maintained during long
periods without slaughtering.
With waste strengths of 1500-2600 p.p.m. (700-1200 p.p.m. B.O.D.
with blood excluded) B.O.D. the usual style of trickling filter will
not provide satisfactory treatment, without two or more stages, or
else a high recycling ratio. Intermittent slaughtering schedules permit
the conventional filter to dry out between uses and thus damage the
biological flora in the filter. Tests in this study yielded less than 10%
reduction in B.O.D. using a conventional six-foot deep filter. The
two to three inch stone originally tried was removed and replaced
with "rice" and "buckwheat" anthracite coal to a depth of six feet.
During five months of operation the coal filter approached a B.O.D.
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