Effect of Surfactants on the Biodegradation of Organic Matter in Industrial Wastewater

While using the contemporary mathematical models for the simulation of activated sludge systems,it is necessary to describe quantitatively the kinetics of microbiological process and to characterize wastewater components in the influent and activated sludge. Kinetic parameters of the aerobic biodegradation of organic matter in wastewater containing synthetic surfactants in an activated sludge system were determined and discussed. Also the composition of the tested wastewater was estimated and expressed as COD fractions. Five synthetic surfactants,including three anionic and two nonionic,of different chemical structures were investigated,each of them was tested separately and dissolved in wastewater to obtain a concentration of 50 mg/L,which can be found in some industrial wastewater. The presence of the elevated amount of synthetic surfactants in wastewater decreased the affinity of biomass to substrate. Nevertheless,the maximum specific growth rates(μ max)of heterotrophic biomass exposed to wastewater containing surfactants were high but usually lower than μmax estimated for wastewater without surfactant. Surfactants, which contain a benzene ring,are the most likely to deteriorate wastewater treatment process in the activated sludge system.