The municipal sector has an important influence on the environmental quality of the Danube River Basin (DRB). A significant part of the pollution load entering the river systems originates from urban areas in the form of major point source discharges. The generated domestic and industrial wastewater, which is collected by the public sewer systems from the towns and urban settlements and discharged into the river basin usually contributes to a great extent to the nutrient load and microbiological pollution of the recipient water bodies. The rate of applied wastewater treatment varies widely between the Danube countries. Germany and Austria, the Upper Danube Basin countries, have achieved a level of emission reduction and water pollution control.
Countries in the Middle Danube Basin, and especially in the Lower Danube Basin have been able to afford much less development in the field of municipal wastewater treatment facilities. The absence of municipal wastewater treatment plant for the majority of the settlements, improper operation of the existing ones and obsolete and insufficient sewage systems have led to substantial pollution of the surface and groundwater with nutrients.
The pollution load of the municipal sector originating from rural areas has had a much smaller impact on the river system, because much of the generated municipal wastewater is handled by individual treatment/disposal solutions. These methods involve the danger of soil and ground water contamination in the first place.
Municipal solid waste disposal sites are also a common cause of potential hazard for water resources, especially in cases which involve the application of improper technology or inappropriate location of the disposal site, often close to the river bank or watercourses and ground water aquifers.
Approximately 60 per cent of the overall amount of wastewater generated in the DRB comes from the municipal sector. The main activities (causes) contributing to water pollution in the municipal sector include: untreated or inadequately treated municipal wastewater; industrial discharges into public sewer systems without necessary pre-treatment; unsuitable management/treatment of solid and liquid wastes; operational and maintenance problems in the management of sewerage and treatment facilities.
The main objectives of the general strategic approach adopted by the countries in the Danube Basin concerning the related municipal developments include:
The Danube countries are differently involved in the realisation of the above strategies, depending on the level of their economic development and their existing municipal infrastructure.