Section Six
INDUSTRIAL WASTES -D. FOOD AND
BEVERAGE WASTES
84    ANAEROBIC AND AEROBIC OPTIONS IN TREATING FOOD
INDUSTRY WASTEWATER
J. A. Oleszkiewicz
Environmental Engineering Division
Department of Civil Engineering
University of Manitoba
Winnipeg, Manitoba, Canada R3T 2N2
J. E. Hutchison
MacLaren Engineering Services Ltd.
Winnipeg, Manitoba, Canada R3L 2T4
INTRODUCTION & OBJECTIVES
In an attempt to upgrade the performance of the Portage la Prairie municipal wastewater treatment
plant (MWTP) it was proposed to apply anaerobic pretreatment to wastewater from the Industrial
Park (IP) which contributed approximately 80% of the overall BOD load and only 20% of the
combined flow. Pilot scale treatability studies1 have shown that the IP wastewater is amenable to
anaerobic treatment in an upflow hybrid reactor packed with random media. The two main IP
residents are a potato processor (french fries) and a pea processing plant. Only the potato processing
manufacturer pretreats its effluent by screening and sedimentation. Both streams are discharged to a
common wet well from which the waste is pumped to the municipal trunk sewer. Concerns were raised
as to the compatibility of the aerobic activated sludge treatment units and the effluent from the
anaerobic pretreatment.
This chapter will present the elements of the cost-effectiveness analyses that resulted in selection of
the anaerobic-aerobic treatment sequence. In the second part the chapter will present the results of
evaluation of the compatibility of the anaerobically pretreated Industrial Park wastes with the aerobic
treatment.
SELECTION OF THE OPTIMUM TREATMENT/UPGRADING SYSTEM
The existing wastewater collection system in Portage La Prairie comprises gravity sewers and a
network of pumping stations and forcemains. The flat topography of the area has limited the use of
deep trunk sewers. Industrial wastewater and municipal wastewater are combined in the collection
system and directed to the municipal wastewater treatment plant (MWTP) as shown in Figure 1.
The industrial wastewater and municipal flows and loads are presented in Table I. The Industrial
Park contributes 80% of organic load and roughly 20% of the total flow.
In determining the preferred system for upgrading the existing Municipal Wastewater Treatment
Plant, the existing facilities were inspected and the present loading, treatment capabilities and operating costs were reviewed. The existing deep shaft/flotation tank system followed by the aerated lagoon
was found to be overloaded and was considered to need either supplementary treatment facilities or
completely new facilities. The MWTP has suffered from chronic sludge loss and due to very short
HRT (1 h) and low SRT could not accomplish nitrification. In order to evaluate an initial list of
approximately 20 upgrading alternatives, a "decision tree" approach was implemented. This "decision" tree is illustrated in Figure 2. Preliminary cost estimates were utilized in making decisions on
preferred options and more detailed cost estimates were completed for the preferred system.
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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