DEGREE OF WATER EUTROPHICATION IN THE TERMINAL BASIN OF THE DANUBE. CASE STUDY

Abstract

Due to human activity, there are some changes in the composition of surface waters, especially near the industrial plants and cities. Wastewater, insufficiently treated, affects negatively the quality of the emissary they reach. The discharge of poorly treated municipal sewage and industrial surface waste water has serious consequences for the natural phenomenon of self-purification, water Borcea branch and the Danube are now reaching the limits of the natural possibilities of biogeochemical balance recovery. In the present study two sources of waste water were taken into discussion, with important contribution of pollutants reaching the terminal basin of the Danube from the Waste Water Treatment of CAƒlAƒraAŸi town and a meat processing plant, representative for the businesses in the county. The indicators followed in the study were: chemical consume of oxygen, biochemical consume of oxygen, ammonia nitrogen, total phosphorus. In recent months, by the rehabilitations that have been already made in the treatment plant, the water quality discharged into the environment improved, from physical chemical point of view. From the evolution of the main indicators analyzed, it is found out a decrease in content of organic substances and water eutrophication agents (total phosphorus and ammonium ion),  their  values ​​reaching nearer to the standards required by  the legislation in force.