E-Andrew Sindt Creative Component S11.pdf

4.2.2 BNR-S1 Sensitivity AnalysisIn addition to the regular mode sensitivity analysis, a less intensive analysis was performed on the BNR-S1 mode. This was deemed necessary for the BNR-S1 simulator calibration because of the differencesbetween the regular and BNR-S1 mode operating phases. The BNR-S1 mode contains an anaerobicphase and the regular mode does not. Also, the BNR-S1 mode contains alternating oxic-anoxic phaseswhich are not included in the regular mode. An analysis of the complete list of simulator parametersgiven in Table 3.5 was completed at values of +20% and -60% of the simulator parameter default values.A table containing the results of this analysis is included in Appendix II. Including the parameterscovered in the regular mode sensitivity section above, two additional operating parameters showedsignificant importance to the calibration of the BNR-S1 mode. These two simulator parameters are theheterotrophic kinetic parameter- substrate ammonia half saturation concentration, and the PAOstoichiometric parameter- aerobic P/PHA uptake. Also, an increase of 20% in the PAO stoichiometricparameter P/Ac release ratio showed an 18% change in effluent TP concentration.4.2.2.1 Substrate (NH 4+) half-saturation concentrationThe ammonia half-saturation concentration is the concentration of ammonia that supports an uptakerate of one-half the maximum rate. The BioWin user manual simply explains the substrate (NH 4 + ) halfsaturationconcentration as impacting the residual ammonia concentration in the effluent (BioWin usermanual). The manual also notes that the parameter value is typically low for municipal plants. Thisassumption may not apply since the Grundy Center wastewater treatment plant receives industrialwaste.Substrate half saturation concentration can be related to the maximum specific growth rate of AOBsthrough the typical equation for substrate utilization rate, (equation 8). Equation 7 is from Metcalf &Eddy’s Wastewater Treatment and Reuse text and is a general equation which may not describe theexact process in BioWin. This equation can be used to describe COD consumption by heterotrophicbacteria or NH 3 consumption by autotrophic AOBs.For autotrophic AOBs, = substrate utilization rate, g NH 3 /m 3 /d= maximum specific growth rate of AOBs, g new cells/g cells/d= AOB biomass concentration, g/m 3= growth limiting substrate concentration, g NH 3 /m 3= true yield coefficient, g new cells/g NH 3 consumption= NH 3 half-saturation constant, g/m 3The range for ammonia half-saturation values has been reported to be between 0.5-1.0 g NH 4 + -N/m 3(Tchobanoglous et al., 2003).[8]53