Impact assessment of wastewater discharge on water quality of DTD canal Bečej–Bogojevo

Abstract

Pressure and impact analysis requires information on the main drivers and changes in conditions. In order to analyze such pressures and impacts, each river basin requires: an analysis of its characteristics, a review of the impact of human activity on the status of the surface water and an economic analysis of water use. Pressure and impact analysis plays a central role in the planning of river basin management. The quality of the stream at any point depends on several major factors: lithology of the basin, weather conditions, climate and human impacts. Most of the polluters are located in the big cities next to the DTD Bečej–Bogojevo canal (Odžaci,Vrbas, Srbobran and Bečej). Per year, 2900000 m3 of wastewater was discharged into the Bečej-Bogojevo section of the DTD canal: 1,4 t COD, 0,8 t BOD, 260 kg of nitrogen, 19 kg of phosphorus and 282 kg of suspended solids. Of the total volume of wastewater, 20% comes from industry and 80% from municipal wastewater. Most of the wastewaters from the studied polluters is discharged untreated or insufficiently treated (only primary treatment). This poor quality wastewater threatens the receipients into which its is discharged. Comparison of the wastewater quality results to the Decree on emission limits and deadlines for their achievement, shows that many polluters exceed the limits for all parameters (COD, BOD, nitrogen, phosphorus and suspended solids). On the basis of the physicochemical analysis of the water from the DTD Bečej–Bogojevo canal it can be concluded that the water quality is unsatisfactory. According to the national legislation, the water quality exceeds the values for good potential streams for most parameters at all sampling locatio dissolved oxygen, organic matter and nutrients). Thus, we can conclude that the water in the studied section of the DTD Bečej–Bogojevo canal does not meet the criteria for „good ecological potential“. The most vulnerable locations are downstream of the Vrbas and downstream of the Bečej, while the best quality canal water is at the furthest upstream location (CS Bogojevo). Risk assessment, based on monitoring results, indicates that the water of the studied section of the DTD Bečej–Bogojevo canal is probably at risk of failing to meet the objectives of the Water Framework Directive, as 33% of the analyzed parameters to calculate specific risk ratios were greater than 1, and thus falls into the category of medium risk pollutants. In order to achieve the quality (to achieve good status and good potential), there must be a response from industrial producers, which consists primarily of comprehensively understanding the problems and implementing measures to minimize the impact of these problems.