The effect of thermal discharge on oxygen demands in the Assiniboine River

Abstract

The effects of the Brandon Generating Station's cooling water discharge into the Assiniboine River were investigated from January 10 through March 14 of 1975. The biological reaction rates of the carbonaceous and nitrogenous stages of deoxygenation at various river temperatures were evaluated and confirmed by a simulated. laboratory study. The thermal discharge does not appear to have any adverse effects on biological reaction rates. The biochemical oxygen demand in the river during the winter months is low. The simulation laboratory study concluded that if sufficient substrate (ammonia) is available, nitrification can account for a higher oxygen demand than the carbonaceous stages of deoxygenation. The simulation study also indicated that nitrification may occur at temperatures below 5oC.