Determination of the oxygen profile in a nitrifying Moving Bed Biofilm Reactor by microelectrodes and a mathematical model

a) Applied Mathematics Group, Malmo University, SE‐205 06 Malmo, Sweden. E‐mail: alma.masic@mah.se; nco@mah.se; heyden@mah.se b) Alfa Laval Copenhagen A/S, Maskinvej 5, DK‐2860 Soborg, Denmark. E‐mail: jessica.bengtsson@alfalaval.com c) AnoxKaldnes AB, Klosterangsvagen 11A, SE‐226 47 Lund, Sweden. E‐mail: Magnus.Christensson@anoxkaldnes.com In this work, the oxygen profile of the biofilm within the BiofilmChip P carriers is presented, based on two different methodologies. Firstly, the oxygen profile was measured on actual carriers that have been used in a MBBR and secondly, the oxygen profile was estimated, based on a mathematical model of the biofilm for this reactor. A lab‐scale Moving Bed Biofilm Reactor with BiofilmChip P was operated for nitrification using a synthetic medium containing ammonia chloride without any organic substrates. DO and temperature were maintained at 5 mg/l and 10‐12°C, respectively, to replicate design conditions for nitrification in colder climates. Measuring of the oxygen profile in situ the nitrifying biofilm was made with a Clark‐type oxygen microelectrode.