Bioxidation of Oil Refinery Wastewater Does Work.
Part I — Winnepeg Refinery
J. L. HARRISON, Coordinator of Laboratory and Economics
Imperial Oil Enterprises, Ltd.
Winnepeg, Canada
INTRODUCTION
Winnipeg Refinery is situated about nine miles north and downstream of the City of
Winnipeg, on the Red River. The city, with a population of 530,000 is at the geographical
centre of Canada, the largest city of the Prairies and the fourth largest city in Canada. It is
an important headquarter for the grain trade, a main cultural centre, and the gateway to the
large mining areas in the north.
The Red River has its origin in the U.S.A. and flows north through the city to Lake
Winnipeg, about 65 miles away. The Assiniboine River flowing from the west, joins the Red
River in the city. Both rivers are used for transportation, irrigation, industrial cooling
water, recreation, and sport fishing, and both are relatively slow-flowing, meandering rivers
common to the Prairies.
The Red River is not used for any municipal water supply but rather has been used
extensively in the past for sewage dilution. However, the Metropolitan Government has
undertaken a comprehensive program of river clean-up, and by early 1973, with the
construction of the South End Pollution Control Centre (Sewage Treatment Plant), all
sewage in the greater Winnpieg area will be given primary and secondary treatment.
Winnipeg Refinery of Imperial Oil Enterprises Ltd. is essentially a Fuel products
refinery with a capacity of 22,500 barrels per day of Western Canada crude oil. Process units
include an Atmospheric and Vacuum Distillation Unit, Fluid Catalytic Cracking Unit,
Alkylation Unit, Powerformer, Middle Distillate Hydrofiner, Sulphur Recovery Unit,
Asphalt Blender, Product Treaters, and Waste Treatment Facilities. The Refinery uses
about 2,000,000 imperial gallons per day of water from the Red River.
The Manitoba Clean Environment Commission is the regulating authority for wastes
discharged into bodies of water outside Greater Winnipeg. Within the area of Greater
Winnpieg, including a buffer zone in which the Refinery is located, the regulating authority
has been the Metropolitan Corporation of Greater Winnipeg Waterworks and Waste
Disposal Division. In 1961 this body granted the Refinery a temporary license to discharge
waste water into the Red River and, after demonstration of adequate performance of our
treatment facilities, in 1971 Metro issued a continuing license to permit continuance of
discharge of waste water from the refinery.
Target levels stipulated by Metro for the Refinery Effluent were:
Phenol
0.75 mgs./1. max.
BOD
30 mgs./l. max.
Susp. Solids =
30 mgs./1. max.
Sulphides =
1 mgs./l. max.
Total Oil      =
15 mgs./1. max.
pH
5.5 to 9.0
Most of these levels were not obtainable with the previous waste water treatment facilities,
which consisted of unit oil-water separators and two circular Dorr oil-water separators
which were operated in parallel. A study was undertaken to see what would be required to
meet the new water quality objectives and Dr. H. Halvorson, a micro-biologist at the
University of Manitoba, was engaged. His studies showed that a biological oxidation
process would be necessary and would do the job. Underwood McLellan and Associates
were then hired to study the problem and in 1966, recommended the installation of the
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