NÄRSALTRETENTION I EN NYANLAGD DAMM I SKÅNE II. DAMMARS KOSTNADSEFFEKTIVITET OCH POTENTIAL FOR NÄRSALTREDUKTION Nutrient retention in a created pond in southern Sweden II. Cost effiency and potential for nutrient reduction of created ponds

The cost for reduction of nitrogen in created ponds does not exceed 45 SEK per kilogram nitrogen. This result is based upon the costs for the creation of ponds with a total area of 27 hectares in southwest Scania 1992-1996, and results from nitrogen budget studies of one pond during three years. Three municipal wastewater treatment plants have been rebuilt for nitrogen reduction during this period of time. The specific cost for nitrogen
reduction in these plants is estimated at over 50 SEK per kilogram.

Wetlands constituted 4 % of the river catchment area in the beginning of the 19th century but only 0,3 % today. A planned restoration of wetlands will increase this fraction to about 1 % which will reduce the nitrogen transport with 15%. The national aim of a 50% reduction will not be reached within the foreseeable future.