Kväverening utan kolkälla / Nitrogen removal without an organic carbon source
Many waste water treatment plants in Sweden needs to improve the nitrogen removal in the coming years in order to fulfill stringent regulatory requirements with respect to nitrogen in the final effluent from today’s level of 15–20 mg/l to 8–10 mg/l. At waste water treatment plants having anaerobic digesters, the nitrogen content in the reject water can contribute with up to 20 % of the nitrogen load at the plant. An alternative to expansion of the biological treatment stage with extra denitrification volume, could be a separate stage for treatment of reject water. A process technology where nitrogen can be reduced without using a carbon source by ANAMMOX bacteria have been developed. Among the advantages of this process is the compact footprint (app.1:20) compared to the volume required for the conventional activated sludge processes. In October 2011, a pilot scale tests will be implemented with the ANAMMOX-process at Simsholmens wastewater treatment plant in Jönköping. The aim of the pilot test is to document the effect of separate reject water treatment with respect to reducing the internal nitrogen load at the plant. In addition, an evaluation of the saving potential compared to conventional expansion of the biological activated sludge volumes will be performed.