E-Andrew Sindt Creative Component S11.pdf

4.2.2.2 Aerobic P/PHA uptake and P/Ac release ratioThe aerobic P/PHA uptake parameter is described by the BioWin user manual as the “Amount of Pstored per unit PHA oxidized in aerobic conditions” (EnviroSim, 2010). The P/Ac release ratio parameteris explained as the, “Amount of P released for one mg (milligram) of acetate sequestered in the form ofPHA” (EnviroSim, 2010).As previously discussed, enhanced biological phosphorus removal (EBPR) involves a number of stepsincluding alternating oxic-anaerobic phases in order to successfully achieve enhanced phosphorusuptake. During the anaerobic phase, the hydrolysis of poly P releases phosphorus from the cells into thetank. Then, during the aerobic phase PAOs use stored electrons as energy to “invest” in the storage ofpoly P (Rittman and McCarty, 2001). In order for EBPR to be successful, more P must be taken up duringthe aerobic phase than released during the anaerobic phase. The initial consensus was that in order tooptimize EBPR, the anaerobic P release must be minimized. This was attempted by boosting volatilefatty acids and other RBCOD components in order to limit the amount of P released back into the tankduring the anaerobic phase.A full-scale study completed by Narayanan et al. (2006) suggests that aerobic P uptake is more critical tothe success of the process than anaerobic P release. The researchers never observed P release as alimitation on the process performance through all testing completed. Further, the researchers foundnearly all performance upsets were linked to a disruption of aerobic P uptake. Either parameter couldbe used to adjust the TP effluent concentration in BioWin. Aerobic P/PHA uptake was selected as theparameter to adjust effluent TP concentration for the BNR-S1 mode based on the research workcompleted by Narayanan et al. (2003).4.3 Simulator CalibrationData obtained from sensitivity analyses were used to calibrate the regular mode and BNR-S1 mode tothe respective observed data obtained by Ersu et al. (2008). According to WEF MOP No. 31, deviationsof predicted values from observed values of 10 to 40% are not uncommon for dynamic simulations. As ageneral rule, acceptable deviations of predicted values from observed values were those that were lessthan 20%, preferably less than 10% with a few exceptions discussed below.4.3.1 Regular Mode CalibrationCalibration for the regular mode focused on fitting the model of observed TSS, TN, NH 3 -N, NO 2 - -N, andNO 3 - -N effluent concentrations. Table 4.1 contains a comparison of observed values from Ersu et al.(2008)Table 4.1- Regular mode effluent quality from default simulator parameter settingsTSS pH cBOD TN NH 3-N NO 2 - -N NO 3 - -N TP COD F. CODObserved (mg/L) 15.1 6.8 - 19 1.5 3.4 10.5 6 - 26.7Default (mg/L) 8.81 6.94 4.31 7.63 0.16 0.04 4.55 6.46 37.15 26.33% deviation -41.66 2.06 - -59.84 -89.33 -98.82 -56.67 7.67 - -1.3954