BIOLOGISK AVLOPPSRENING En utredning om kvävereducering i avloppsvatten / Biological Wastewater Treatment An investigation of nitrogen reduction methods
The eutrophication of the Balric Sea has resulted in a decision in the Swedish Parliament that every wastewater treatment plant on the Baltic coast with more than 2000 customers has to have a nitrogen reduction system. This investigation compares the three methods for nitrogen reduction, that are in full use in Sweden: constructed wetlands, fluidized beds and conventional nitrogen reduciion. The three methods are compared in three respects: performance, economy and envlronmental impacts. The invesdgadon shows that there is not a single best method, they have all their advantages and disadvantages. When choosing a reduction system, it is necessary ro take into consideration how the wastewater plant is constructed, number of persons served, available space, geographical conditions and recipient condition, in order to achieve the most cost efficient system.