TREATMENT OF BEEF SLAUGHTERING
AND PROCESSING WASTEWATERS USING
ROTATING BIOLOGICAL CONTACTORS
Frederic C. Blanc, Associate Professor
James C. O'Shaughnessy, Associate Professor
Department of Civil Engineering
Northeastern University
Boston, Massachusetts 02115
Steven H. Corr, Vice President
Weston & Sampson Engineers, Inc.
Boston, Massachusetts 02110
INTRODUCTION
This paper presents results from a laboratory bench scale investigation which evaluated the ability
of the rotating biological contactor (RBC) process to treat combined beef slaughtering and processing
wastewater without prior pretreatment. The study was conducted as part of the industrial waste design
for a proposed conversion of an existing meat facility. Regulatory agency requirements, energy considerations and site limitations prevented the use of large anaerobic pretreatment lagoons which are
common in the meat industry and cause the aerobic RBC process to be most economically feasible.
Due to Koshering operations in the meat processing, varying high sodium and chloride concentrations
were anticipated in this wastewater. Thus, the study was also designed to investigate the effects of
such concentrations of the two ions on the RBC process.
The purposes of a treatability study such as this one are to evaluate treatment kinetics, waste loading rates, removal efficiencies and sludge production rates in addition to revealing unanticipated characteristics and problems associated with both wastewater and treatment process.
BACKGROUND
Waste Characteristics
More than 500 mgd of wastewater flow is generated by the slaughtering and meat processing
industry in the United States. The characteristics of this industrial wastewater vary with the type of
animal slaughtered, the nature of the operation, the number of animals processed per day and the
location of the facility. Typically, the wastewater will contain blood, paunch manure, fat solids, meat
solids, grease, soil and hair. Additional materials are contributed to this wastewater from plant maintenance and in-house uniform laundry operations.
The paunch manure is a major waste component. Each beef stomach or paunch contains from 65
to 80 pounds (30 to 36 Kg.) of manure. Over 100 gallons (0.38m3) of water can be required to wash
out a single paunch. Often the impact of the paunch manure on the wastewater is reduced by collecting some of the paunch in a separate screw conveyor or screening out solids.
Blood is the other major wastewater component. The BOD5 of whole blood is about 100,000
mg/l. Blood coagulates rapidly. Because of this fact, more frequent wash-up occurs in the slaughtering areas where most of the blood is generated. Typically for beef slaughter, the amount of blood
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