Section Six
INDUSTRIAL WASTES
C. FOOD PROCESSING
78    DESIGNING A SEQUENCING BATCH REACTOR SYSTEM
FOR THE TREATMENT OF HIGH STRENGTH MEAT
PROCESSING WASTEWATER
Kenneth A. Mikkelson, Manager of Process Engineering
Aqua-Aerobic Systems, Inc.
Rockford, Illinois 61130
Kenneth W. Lowery, Chief Operator
F.B. Purnell Sausage Co.
Simpsonville, Kentucky
HISTORY OF WASTEWATER TREATMENT AT F.B. PURNELL SAUSAGE CO.
Like many food processors, the F.B. Purnell Sausage Co. employed a flow-through activated
sludge system followed by a polishing lagoon for treatment of process and other wastewater. Due to
widely varying flows and highly variable organic loading rates, the flow-through system often was
unable to produce the required effluent quality. Under such hydraulic and organic loading conditions,
Purnell Sausage Co. was not able to meet its effluent discharge permit. In many states, the government has set guidelines whereby the best technology available must be used to meet the goal of zero
discharge of pollutants. While the State of Kentucky has not yet imposed such strict discharge
limitations, Purnell wanted to ensure that, with the installation of a new wastewater treatment system,
the company would have the ability to meet more stringent discharge limitations in the future.
SELECTION OF A TREATMENT SYSTEM
After investigating several wastewater treatment systems, Purnell's consulting engineer, A.W.
Goodman & Associates of New Albany, Indiana, decided on a three-step process. The wastewater
treatment system was installed with dissolved air flotation for removal of blood and for grease
recovery; and a sequencing batch reactor system for BOD, suspended solids and nitrification. In
anticipation of future, more restrictive discharge requirements, Goodman & Associates also recommended the installation of a tertiary sand filter.
The SBR process was chosen for several reasons, including:
• It requires a minimum amount of land for installation.
• Capital costs are significantly less than a flow-through activated sludge system.
• It is controlled by microprocessor and requires considerably less operator attention than
a comparably sized flow-through activated sludge system.
• Its flexibility enables it to be operated for today's discharge requirements and future,
more stringent requirements usually without the addition of equipment or additional
reactors.
The sequencing batch reactor is an activated sludge process in which all treatment steps, including
clarification, take place in a single reactor. In a flow-through activated sludge system, the waste flows
continuously through a series of basins composed of a minimum of aeration and secondary clarification (Figure 1). Discharge is continuous.
In the SBR process, the influent also feeds continuously, but in batches to each SBR reactor (Figure
2). For example, in a two reactor system, 100% of the influent flows to each reactor 50% of the time-
47th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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