Water is the most important resource for life and the global ecosystem. Although the continent does not face overall water shortages, a global water crisis exists. Even if Europe is not considered to be water scarce or water stressed, water quantity in Europe's south and water quality throughout Europe are far from being satisfactory. Therefore the European Union's environmental legislation invests particular interest in regulating the water area adopting the Water Framework Directive 2000/60/EEC in order to expand its aim at considering and protecting all waters. Accordingly, all waters must achieve or maintain a good status, which should be attained by setting up the river basin as single management system, supporting the establishment of an appropriate water pricing policy and ensuring both active participation of all stakeholders, NGOs and local communities as well as the reduction and control of pollution from all sources such as agriculture, industrial activity, urban areas, etc. This paper focuses on the control of pollution, its reduction and the improvement of the water quality in areas used for agriculture. For this purpose a field-based study was carried out in northern Germany, in Hohenwestedt (dairy industry) and Uelzen (sugar-beet industry) to determine the effects of sprinkling untreated wastewater from food industries (sugar and dairy industry) on land used for agriculture with regard to nitrates in soil, soil water and the upper groundwater layer. In order to compare the impact of wastewater sprinkling on soil and water in areas used for agriculture two kinds of areas were chosen for each location: One which had been alternatingly sprinkled with wastewater for over 20 years and another one which had never been irrigated with wastewater, but only with potable, ground- or spring water. However, both areas were subject to identical conditions including the climatic situation, crop cultivation, agricultural management etc. For each area all essential nitrogen compounds were analysed at various depths using both regular and biochemical test methods. The recorded results indicated that all areas sprinkled with untreated wastewater from food industries had reduced NO3- concentrations in nearly all soil layers and groundwater when compared with the non-sprinkled areas used for agriculture. The nitrate concentrations in soil water and groundwater of the wastewater sprinkled areas lie all below the limit for potable water of 50 mg/l. Wastewater fosters two processes, N-immobilisation and denitrification. The denitrification activity in fields sprinkled with wastewater is up to 12 times higher than this in areas were no wastewater was applied, but similar agricultural management occurred. Based on this study, wastewater irrigation can be suggested as a method for improving water quality and specifically reducing nitrate in soil, soil water and especially groundwater.
