Experimental data in forms of vertical concentration profiles has been provided from a full scale submerged denitrification filter with biocarbone as filter material. Denitrification rates were determined in full scale under different loads of nitrate and methanol with methanol in excess. Vertical concentration profiles of nitrate and methanol have verified kinetics in the half-order region with removal rate constants in the range of k0.5A = 0.13-0.21 g N0.5 m−0.5 d−1 (0.5 order for partial penetration in the 0 order intrinsic concentration range). The removal rates found are low with methanol as carbon source as compared to information from literature. The experience with detailed mathematical modelling is that “best fit” can be achieved by different sets of parameters with the computer program AQUASIM. Full scale experiments have to be supplemented with dedicated laboratory scale experiments to determine all important parameters.

Two experiments were performed in order to investigate the anoxic and the aerobic degradation of filtrated organic matter in a biofilter. In submerged lab. scale reactors with Biocarbone media as filter material, accumulated particulate organic matter from pre-settled wastewater served as the only carbon source for anoxic and aerobic degradation respectively. In order to utilise the accumulated organic matter, the bacteria in the biofilm had to produce extracellular hydrolytic enzymes for the hydrolysis process. In the first experiment with anoxic degradation, a significant denitrification occurred. The maximum nitrate removal rate, with particulate organic matter as carbon source, was found to 1 g NO3-N/ (m2d), declining exponentially as rA.NO3-N = 1.04 e −4t g NO3-N/(m2d) (t = days). A significant release of soluble organic matter (< 0.45 μm) and production of inorganic carbon to the bulk liquid was observed as an indication of hydrolysis taking place. The second experiment was designed as a series of on-line OUR batch experiments in a biofilm reactor with recirculation, in order to investigate further the degradation of particulate organic matter. After the biofilm had been starved in order to remove the original organic matter, particulate organic matter was added and the degradation kinetics recorded. The initial removal rate was high, rA.02 = 2.1 g O2/(m2d) though fast declining towards endogenous respiration. The respiration ratio between removed oxygen and produced carbon dioxide was declining from 1.3 to 1.0 g O2/g CO2 during the degradation of organic particulates. The respiration ratio during endogenous respiration was determined to be 0.7 g O2/g CO2 indicating a thorough mineralisation of biomass.