Comparison of Operational Characteristics of UASB and ABR : Organic Removal Efficiency and the Variations of PH2 and PCO

초록

The COD removal efficiency of UASB and ABR were compared by increasing organic loading rates(OLR). In addition, the variations of PH2 and PCO were monitored to test the acceptability of those as the process monitoring parameters. The COD removal efficiency of UASB decreased slowly to 76% as OLR increased up to 10g COD/L-day, and abruptly deteriorated to below 50% at 15g COD/L-day. On the other hand, COD removal efficiency of ABR was generally higher than that of UASB, and was kept 72% even at an OLR of 20g COD/L-day. This difference might be resulted from the fact that the configuration of ABR may provide more distinct phase separation than that of UASB. The behaviors of PH2 and PCO were generally similar for both reactors, although they were kept lower in ABR. Fluctuations in PH2 and PCO were found during steady-states as well as transient periods, which diminishes the value of them as the reliable monitoring paramenters. Therefore, PH2 and PCO should be used with the easily monitored parameters such as gas production, gas composition, and pH to prevent the upset of the reactors.