KINETIC AND MOLECULAR CHARACTERIZATION OF A LABORATORY-SCALE, TWO-SLUDGE NITRIFYING SIDE-STREAM REACTOR SYSTEM

An investigation was undertaken to evaluate the impact on biokinetics of the input of biomass from a side-stream treatment system. A novel molecular biology technique was utilized in an attempt to improve estimates of biokinetic parameters based on respirometry. Real-time PCR and respirometry was performed on biomass removed from laboratory-scale activated sludge reactors receiving input biomass from side-stream reactors simulating treatment of anaerobic digester supernatant. Biokinetic estimates obtained using traditional respirometric techniques coupled with 1-step and 2-step models for nitrification exhibited wide variability and did not demonstrate improved kinetic properties in reactors receiving input biomass. Real-time PCR utilizing SYBR Green chemistry could not be optimized for the primer set selected. Correlation and slope coefficients were outside acceptable ranges. A revised procedure using a Taqman chemistry and a modified primer set was being optimized at the time this manuscript was submitted.