Produktionsvåtmarker mot övergödning
In ambition to produce more and better harvests, artificial fertilizers are used to produce a better growth of crops in the agriculture landscape. This contributes to leakage of nutrients. Our forests also exhibit a leakage of nutrients. Air pollution contributes to more nutrients. High precipitation with high water flows as a consequence seems currently to occur more frequently in the county of Halland. The high precipitation could be a consequence of climate changes. Increased precipitation increases the flow of nutrients into watercourses and causes eutrophication problems. For the best possible nutrient uptake, wetlands should be designed after local circumstances. One way is to construct production wetlands where biomass in form of plants is harvested to remove nutrients. In order to get the best possible decrease of eutrophication, production wetlands should be constructed on a large scale. Often flooded areas are suited for constructing new production wetlands. The production wetland could be planted with common reed (Phragmites australis) which grows fast and creates a large biomass and therefore a high nutrient uptake. In order to take in water and emptying a production wetland before harvesting, it should also be constructed with controllable in - and outflow of water. Harvesting is a sensitive aspect and the production wetland should be constructed so harvesting with agricultural machines is possible to reduce the costs. The harvested biomass should be used in biogas production. The material that remains after digestion in the biogas plant can be used as fertilizer on agricultural land to replace artificial fertilizers. This contributes to more ecological agriculture where artificial fertilizers are forbidden. From an environmental point of view, this process is clearly the best way where nutrients can be re-circulated.