Pollution of lake water

Pollution of lake water is caused by the inputs of polluted river water, grotmd water and acid water from metal mines. Pollution and acidification of lake water have been considerably investigated by the model analyses. pH and the changes in the water quality of lake water inputted by acid rainwater and acidified river water will be considered below. 

Due to these reactions, pH value is enhanced. Microorganisms cause oxidation-reduction reactions such as 

The reactions (6.36), (6.37), (6.38), and (6.39) lead to the change of pH. The other examples of microorganisms activities controlling pH are reductions of Fe (0H)3 and Mn02, causing increasing pH. These reactions are written as 

Calculation based on perfectly mixing non-steady state model was done by Hanya (1979). Mass balance equation for this model is given by 

Temporal variation in water quality for Eq. (6.43) is shown in Fig. 6.16. This figure illustrates that lake water is significantly polluted after about four times of residence time. Volume inflow rate is same to volume outflow rate in the above case. However, volume inflow rate is generally different from volume outflow rate. In this case 

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