A commentary on the respirometric evaluation of biodegradable cod fractions in industrial wastewater

This paper presents considerations on selected methodological aspects of respirometric COD fractionation in industrial wastewater which may differ from more common applications of such methodology for municipal wastewater. This concerns: the presence of interfering substances; problems with the elimination of nitrification; the importance of recognising biomass metabolism; differences of growth coefficient; the inclusion of non-canonical COD fractions and toxic effects. The discussion is based on a literature review and the authors’ own experience. As a conclusion, a preparatory procedure is proposed to assure the correct performance of respirometric COD fractionation for industrial wastewater, especially for more complex chemical effluents.