The use of oxygen in a rotating disc process

Abstract In semi-technical biodisc equipments casein was degradated in parallel experiments in an oxygen- and an air-atmosphere, respectively. Loads were varied: water and oxygen flow rates were kept about constant. From in- and effluent COD, O2, pH-values sludge and nitrogen components were determined. It was found that with higher loads in an oxygen atmosphere COD-reduction is higher, sludge production is lower and its settleability is better than in an air atmosphere. The rate of degradation of casein in relation to the conditions of treatment in the experiments with oxygen could be described using an equation similar to that used by Monod. From this equation the value of the maximum attainable rate of degradation and the saturation concentration of casein have been derived for a plant using an atmosphere of oxygen: these values are shown to be characteristic for the nature of the biological film involved.