Concentration of contaminants discharged with power station cooling water

The cooling water discharged from a power station may contain dissolved material, in addition to the heat rejected from the station turbines, which must be dispersed away from the power station in a manner which is environmentally acceptable. Mathematical methods are presented for use in the calculation of the rises in background concentration arising from the discharge of such material into lakes, rivers, estuaries or the sea. The calculations take account of factors including the replacement of the receiving water by freshwater, the available volume of water in the system, the rate at which the material may be degraded in the receiving water and some aspects of the design of the cooling water system. Particular calculations emphasize the different levels of concentration which may be expected from similar discharges into the different types of receiving water body. These examples suggest that for conditions representative of some present power station sites the concentration in a lake may be ten times that in an estuary, and that in an estuary may be ten times that in the sea. Of course, this is not a general result and the concentration level must be calculated for each particular case. The analyses also suggest what hydrographic factors must be measured during field surveys at a particular site if the mathematical methods presented here are to be used for the calculation of concentrations of any discharged material.