BIOLOGISK KVÄVEREDUKTION I REJEKTVATTEN FRÅN SLAMRÖTNING / Nitrogen Removal in Supernatant from Centrifugation of Digested Sludge
Removal of nitrogen from sludge supernatant is one possibility to improve total nitrogen removal efficiency in a sewage treatment plant with about 10 %. The basic treatment gives nitrification and possibility to inoculate the activated sludge process with nitrifiers. This operation improves the plant’s ability to recover nitrification capacity after for instance chock loadings. Denitrification is the next step in process development. Sludge is an interesting internal carbon source, which can be used in the denitrification process. In this study nitrification efficiency was nearly 100 % and denitrification efficiency about 50 % with sludge as the only addition.