CSB-FRAK - Determination of the fractionated COD content in the inflow to the Graz wastewater treatment plant and model scenario analyses with regard to the wastewater treatment plant cleaning performance with changed inflow quantities and changed wastewater quality

For the design of activated sludge plants as well as for the application of wastewater treatment plant models according to the common IWA Activated Sludge Model (ASM) approaches, knowledge of the different COD fractions in the inflow to a wastewater treatment plant is required. Since the inlet to the Graz wastewater treatment plant with a relatively constant COD/BOD5 ratio of 1.8 deviates significantly from the usual ratio of 2.0 for municipal wastewater treatment plants, the individual COD fractions and their variability are determined in the laboratory within the framework of measurement campaigns both in dry weather and in wet weather conditions. Based on this, COD fractionation models adapted to the Graz conditions for dry and wet weather cases will be developed and various scenarios concerning possible changes in the inflow quantities and the COD inflow fractionation will be estimated using an activated sludge simulation model.