EFTERDENITRIFIKATION I SANDFILTER Försök i ett DynaSand-filter / Denitrification in a DynaSand Filter
Denitrification tests with a DynaSand filter have been performed at the Klagshamn sewage treatment plant in Malmö. Effluent wastewater from a nitrifying activated sludge plant was treated in a filter with a surface area of 0.7 m2 and a sand bed depth of 2 m. The grain size of the sand was between 2 and 3 mm. The hydraulic load on the filter during the tests was varied between 4.8 and 10 m/h. An external carbon source was added to the wastewater before the filter. Acetate and methanol were tested. The results gave evidence that high denitrification rates could be reached in a DynaSand filter. The nitrate content was decreased as much as about 20 mg N03-N/l in the filter. The denitrification capacity was dependent on the NOx load and the supply of organic carbon. About 80 g N/m3 *h was removed at a NOx load of about 90 g N/m3*h. The maximum capacity of the filter was not reached during the tests. Grab sampling at different filter levels indicated removal rates as high as about 140 g N/m3*h. “Complete abstract not presented.”