Preliminary Results of a Novel Biological
Process forTreating Dairy Wastes
RONALD L. ANTONIE, Research Engineer
FRED   M.   WELCH,   Manager
Environmental Processes
Research Division
Allis-Chalmers Mfg. Co.
MUwaukee, Wisconsin
INTRODUCTION
For the past several years the Research Division of AlUs-Chalmers has been engaged in the development of a novel, secondary, biological waste treatment device.
The device consists of a series of discs which are mounted on a shaft and rotated whUe
partially submerged in the waste to be treated. A microbial film similar to trickling
filter sUme develops on the surface of the discs shortly after seeding with an appropriate source of microorganisms, such as activated sludge, and provides the microbial
population necessary to oxidize and synthesize the biodegradable materials in the
waste. As the sUme covered discs rotate they carry a film of the waste into the air
where it is aerated to provide the dissolved oxygen necessary for aerobic biological
activity. Operation in this manner utiUzes the rotating disc as a support media for the
microbial population, as an aeration mechanism, and as a means of contacting the
organisms with the waste materials. Based on this manner of operation this waste
treatment device is called the "Rotating Biological Contactor" or "RBC."
The RBC concept was first tested by AUis-Chalmers on domestic sewage. The
results of these tests were very encouraging and led to a series of pUot plant tests
under controlled conditions to study the important variables in RBC operation. A
synthetic waste was used for these tests which consisted of dairy whey soUds and
appropriate nutrients and buffer. During the pUot plant tests the RBC demonstrated
a high capacity for organic removal and showed inherent flexibUity in treating a wide
range of waste concentrations and flow rates.
Because the synthetic waste utiUzed during the pilot plant tests was a dairy byproduct it was thought that the first field application of the RBC should be the treatment of a dairy waste. Several dairies were investigated as potential sites for RBC
testing and a large Midwestern dairy plant was chosen as the most desirable. Field
testing of the RBC at this Midwestern dairy plant is the subject of this paper.
EQUIPMENT   AND   PROCEDURES
In September of 1967 the two-stage RBC system which had previously been
used for the pilot plant testing was instaUed at the dairy plant. The installation is
shown in Figure 1. This system is composed of two identical units connected in
series. Each unit consists of a tank containing 100, three-ft diameter rotating discs and
a settUng tank.
Two wastes were treated during the test program. One was a combined waste
from several sources in the milk plant including wash water from the cleaning of tank
trucks and other equipment, and wash water from cottage cheese processing. The
other waste was whey from cottage cheese processing.
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