Aeration of Milk Wastes
William A. Hasfurther and C. W. Klassen
Principal Assistant and Chief Sanitary Engineer
Illinois Sanitary Water Board
Springfield, Illinois
A little more than two years ago, at the Third Industrial Waste
Utilization Conference at Purdue University, there was some discus¬
sion on the aeration of milk wastes, controlled to give substantial BOD
reduction and yet not involve the exigencies of activated sludge. On
this basis the Dean Milk Company officials received permission to
make such an installation at their processing plants in Huntley, Illinois.
The plant was designed with a relatively shallow aerating tank and
with less air capacity on a BOD basis than would be provided for
an activated-sludge plant. It was intended to convert it to a trickling-
filter-type plant if it failed to produce the expected results.
When the plant was put in operation last spring, it was found
that an activated floe, although poor, formed even at low rates of air
application. The same thing must have been observed elsewhere, since
it is noted that, in general, straight aeration has been discarded for
a simplified form of activated-sludge treatment. Experience has shown
that this simplified activated-sludge treatment can produce satisfactory
results under certain conditions of discharge, control, and dilution, and
that the units are comparatively economical to construct. Through
this method of treatment, the engineers, operators, and milk producers
are trying to eliminate many of the costly features of the treatment
plants built heretofore, and in doing so have come up against numerous
problems, some of which still have to be worked out. In order to de¬
velop the best standards for aeration, treatment of milk wastes, design,
and operating information on such plants currently in operation should
be pooled so that the most efficient design standards can be formulated.
The Dean Milk Company and the Illinois Sanitary Water Board are
presenting the  following information with this  in mind.
The Huntley plant of the Dean Milk Company receives milk both
in cans and tank trucks, and stores, pasteurizes, and bottles it in
paper containers. Daily production during periods when samples were
collected ranged from 104,600 to 155,460 pounds. The daily waste
discharge is fairly consistent except on weekends and holidays.
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