Determination of kinetic and stoichiometric parameters using respirometric method in a membrane bioreactor

Biological treatment of municipal and industrial wastewaters before disharge into water media is the most common way for pollution prevention. The most common wastewater treatment system is known as the activated sludge process. The main aim of biological treatment of wastewater using activated sludge process is to remove dissolved organic and inorganic matters, colloidal and nonsettled solids. The membrane bioreactors have some advantages compared to conventional activated sludge processes. The advantages can be listed as: high MLSS concentrations, high organic loading, low F/M rates, and resistance shocks loadings. Therefore, originated from different industries can be treat in MBRs. The activities, growth rates and consumption oxygen of microorganisms are different in the MBRs treating synthetic wastewaters having different C/N ratios. It is known that the activities of aerobic biological treatment systems at constant temperature, pressure and gas flow are directly related to dissolved oxygen concentration. Therefore, by monitoring dissolved oxygen concentration, it is possible to monitor the performance of microorganisms. In order to determine the performance of the microorganisms in an aerobic system, respirometric method is generally used. ln this study, kinetic and stoichiometric coefficients of the activated sludges in three MBRs treating different synthetic wastewaters having different C/N ratios were determined by respirometric methods. The results indicated that a change in the C/N ratios change oxygen uptake rates, substrat utilization rates and growth rates of microorganisms. The results also indicated that the synthetic wastewaters used in this study were able to represent real wastewaters.