Impact of discharges from wastewater treatment plants

The Saint-François River watershed located in the southern region of Quebec is mostly made up of forest. However over the last few decades several industries and wastewater treatment plants have been set up leaving only the upper parts of the basin in its natural state. The results of the assessments show that upstream of the lowlands the water quality is generally good or satisfactory while in the lowlands area it is poor or very poor. This phenomenon is caused by an increase in the productivity of rivers and lakes due to the increase in nutrients promoted by the growth of cyanobacteria. In this study a mathematical mass balance model will be used to determine the total phosphorus concentration in Aylmer Lake and the degree of impact caused by wastewater treatment plants.