Prospects for reduction of the impact of wastewater discharge from urban areas on surface water quality in view of legal regulations

Abstract

Despite full adoption of EU requirements into current legal regulations in Poland, surface waters as sewage receivers in urban areas still cannot be considered fully protected, especially against contamination from sewer overflows and storm water systems. The examples discussed demonstrate that urban wastewater discharged from sewer overflows and storm water systems during rainfalls has a clearly dominant share in the load of pollutants emitted to the receiver. It is therefore important to develop efficient tools of water protection against these contaminants. Uniform but rather limited provisions applicable throughout the country do not take account of specific local conditions, especially size of wastewater receivers and size and characteristics of the catchment area, preventing therefore effective and economically viable water protection. The results of this research, carried out in Lodz, examining pollution loads discharged from the urban catchment area, illustrate that current approach to surface water protection issues requires a revision. Feasibility of regulatory changes in the area of setting requirements for effective receiver protection against pollutants discharged from urban areas was presented, considering the impact of untreated wastewater on the receiving water. It is also necessary to take comprehensive measures both in terms of research on pollutant emissions and their impact on the receiver and the method to utilize the results of such studies. This would enable more widespread use of urban wastewater discharge system modeling, which in turn would enable a reliable assessment of their impact on the receiver and taking appropriate modernization decisions. All of these activities are preconditions for sustainable rainwater management in urban areas