Åtgärder för reduktion och tillvaratagande av näringsämnen från dräneringsvatten - En tillämpning på Höje å

Sammanfattning: Eutrophication is one of the biggest environmental problems in Scanian waters, where agriculture has the largest input. Through soil cultivation and usage of fertilizers, nutrients are added and released. If no uptake occurs nutrients can be further transported to watercourses through surface runoff or the drainage system. This study investigates three measures to reduce and reuse nutrients from drainage water: production wetlands, phosphorus wetlands and filter substrates. The purpose is a reduced nutrient contribution and a sustainable nutrient handling. The study consists of literature studies, analysis of research and a case study, performed on a stretch of Höje River, affected by eutrophication like many other rivers in Scania. Measures in the case study are suggested further up in the drainage system, reducing nitrogen and phosphorus by 8 % and 20 % respectively. Recycled materials from the measures generally have low nutrient concentrations and uncertainties regarding plant availability in comparison with other fertilizers. Best fertilize potential has anaerobic digestion of common reed, the process does however include several costs. For further studies, suggestion is to include drainage pipes in areas with large nutrient losses in the catchment of Höje River into the water quality program to quantify their contribution to eutrophication.