An approach to the measurement of decay, active fraction of biomass and extracellular polymeric substances: Applied to hydrogen-driven denitrification

A general method for measurement of active biomass and decay coefficient and Extracellular polymeric substances (EPS) concentration in steady-state biomass was developed. The model was applied to the process of hydrogenotrophic denitrification in order to measure biomass constituents and decay and yield coefficients. It was found that steady-state biomass obtained after operation at 20 day solids retention time (SRT) was composed of 41% active biomass, 25.6% cell debris and 33.4% extracellular polymeric substance. The value of 0.041 d(-1), and 0.27 mg active biomass per mg NO3-N were obtained for decay coefficient and true yield, respectively.