ENVIRONMENTAL BIOTECHNOLOGYOne-stage partial nitritation/anammox at 15 °Con pretreated sewage: feasibility demonstration at lab-scaleHaydée De Clippeleir & Siegfried E. Vlaeminck &Fabian De Wilde & Katrien Daeninck &Mariela Mosquera & Pascal Boeckx & Willy Verstraete &Nico BoonReceived: 26 November 2012 /Revised: 28 January 2013 /Accepted: 30 January 2013# Springer-Verlag Berlin Heidelberg 2013Abstract Energy-positive sewage treatment can beachieved by implementation of oxygen-limited autotrophicnitrification/denitrification (OLAND) in the main water line,as the latter does not require organic carbon and thereforeallows maximum energy recovery through anaerobic diges-tion of organics. To test the feasibility of mainstreamOLAND, the effect of a gradual temperature decrease from29 to 15 °C and a chemical oxygen demand (COD)/Nincrease from 0 to 2 was tested in an OLAND rotatingbiological contactor operating at 55–60 mg NH4+–NL−1anda hydraulic retention time of 1 h. Moreover, the effectof the operational conditions and feeding strategies on thereactor cycle balances, including NO and N2O emissionswere studied in detail. This study showed for the first timethat total nitrogen removal rates of 0.5 g NL−1day−1 canbemaintained when decreasing the temperature from 29 to 15 °Cand when low nitrogen concentration and moderate CODlevels are treated. Nitrite accumulation together with elevatedNO and N2O emissions (5 % of N load) were needed to favoranammox compared with nitratation at low free ammonia(<0.25 mg NL−1), low free nitrous acid (<0.9 μg NL−1), andhigher DO levels (3–4 mg O2L−1). Although the total nitrogenremoval rates showed potential, the accumulation of nitriteand nitrate resulted in lower nitrogen removal efficien...
