Lakes in Mecklenburg-Vorpommern: Sustainable Remediation and Restauration
Short profile
Duration
Feldberger Haussee, during a period of intensive calcite precipitation. In spring 2011, the earlier highly polluted lake was treated with a chemical precipitant (poly-aluminium chloride) in order to remove excess phosphorus from the water and to immobilize it in the sediment. The water quality has meanwhile significantly improved and is now in the range typical for mesotrophic lakes.
Concerning lake protection and water quality management, a close and successful co-operation between the Bundesland Mecklenburg-Vorpommern and the IGB exists since the 1990s. The aim primarily was to study problems of lake remediation and restoration as exemplified by relevant lake ecosystems. By integrating the scientific expertise of the IGB, the respective programs acquired a better scientific footing which was one of the prerequisites for sustainable success. An example is the treatment of Lake Schmaler Luzin by artificially induced calcite precipitation. Other examples are the lakes Tiefwarensee and Feldberger Hausee. Sustainability is of significant importance for public awareness and acceptance when it comes to this of this kind of interference with natural habitats. Reciprocally, field experiments may help to improve strategies for careful use and management of lake ecosystems. As a side effect, the studies provided parts of those data necessary for mandatory reports concerning the EU-WFD.
Reloading of the poly-aluminium chloride solution into containers.
By cruising with a floating platform across the lake, the precipitation chemical is spread onto the water surface.
As soon as the precipitant gets in contact with lake water, flocks are formed binding the soluble inorganic phosphorus as well as the phosphorus contained in particles. Within a couple of hours both are transported onto the sediment surface. Additionally, the aluminium layer now placed on top of the sediment acts as a barrier against phosphorus being released from deeper layers.
Long-term trend of phosphorus concentration in the surface water of Feldberger Haussee before and subsequent to the treatment with poly-aluminium chloride. (black dot). The values remain constantly well below the restoration target of 0.035 mg/L.
Long-term trend in water clarity (Secchi transparency) of Feldberger Haussee before and subsequent to the treatment with poly-aluminium chloride. The delay was primarily causes by periods if intense calcite precipitation, i.e. a mineral turbidity which does not constrain the water quality.
Ministerium f. Landwirtschaft und Umwelt (MLU-MV) d. Bundeslandes Mecklenburg-Vorpommern