Denitrification in gravel-pit lakes

By constructing a budget of nitrate inputs and outputs in several gravel-pit lakes and directly measuring denitrification through the emission of N₂O (using acetylene method), it was possible to evaluate the depolluting activity in the lakes in relation to groundwaters. Seasonal monitoring of the denitrification process allowed us to appraise the influence of various factors such as nitrate concentration, the bioavailability of carbon compounds and the temperature. The application of denitrification towards an improvement of the quality of the water pumped in the wellfields is discussed.