NITRIFIKATION OCH DENITRIFIKATION I SEPARATA STEG- ETT KONKURRENSKRAFTIGT ALTERNATIV FÖR KVÄVEAVSKILJNING / Separate Stage Nitrification and Denitrification – a Viable Alternative for Nitrogen Removal?
At GRYAAB’s wastewater treatment plant, Ryaverket, in Gothenburg, pilot plant investigations are being performed for evaluating technologies which can be used to meet anticipated demands for 50 % nitrogen removal. Two alternatives are being investigated. One alternative uses pre-denitrifiction in the activated sludge process. Preliminary results show that this is a functional but expensive alternative that requires considerable space. The second alternative is post-nitrification in a fixed film reactor and recycling the nitrified water to an anoxic zone in the existing aeration basins. Preliminary data from pilot scale fixed film reactors (trickling filter and rotating biological contactor) indicate nitrification rates in the order of 1-2 g N/m2*d. Denitrification tests in a pilot scale, high rate activated sludge unit show denitrification rates up to 10 g N/kg VSS*h using wastewater as the electron donor. “Complete abstract not presented.”