Dissolved gas supersaturation and dilution in thermal plumes from steam electric generating stations

Abstract

The use of natural waters for waste heat dissipation for steam electric generating stations using once-through cooling, creates potential problems of dissolved gas supersaturation in the thermal discharge plume for fish that can reside in the plume. Computations are presented which show the amount of dissolved gas supersaturation that would be expected in thermal discharge plumes employing offshore high velocity discharge and onshore low velocity discharge. It is predicted that dissolved gas supersaturation problems would be rare for steam electric generating stations utilizing high velocity offshore discharge for cooling water/heat dissipation because of the rapid dilution that occurs in the discharge plume. However, problems of this type would be expected for low velocity discharges. It is also shown that the rate of dilution from high velocity discharges would tend to minimize the environmental impact of chemicals (such as chlorine) used for condenser fouling control.