Research On Response Process And Stability Of UASB Biosensor Based On

Up-flow Anaerobic Sludge Bed (UASB) is one of the typical high-rate anaerobic reactors and has been widely used in the treatment of various kinds of wastewater. However, the operation of UASB requires strict conditions and lacks quantitative control parameters, which has limited the application of UASB.Microbial fuel cell (MFC) is a new-fashioned bioreactor, it can convert directly the chemical energy of organic compounds into electrical energy with the catalysis of microorganisms. In recent years, the electricity production principle of MFC has been applied to the wastewater treatment processes by many scholars.For it is difficult to investigate the running state of UASB, a MFC-UASB coupling system is created in this study. MFC-UASB coupling system can examine the feedback of MFC electrical signal, which put to use to determine the operation state of UASB under different conditions. It provides the basis for the application of practical engineering to find out the differences of MFC signal under each operation stage.It is indicated voltage of MFC increases with the improving of UASB organic loading, but it would decreases when the value of organic loading exceeds a certain limit. So we test the MFC electrical signal feedback result by dividing it into the normal loading range and overloading range.It was found the feedback regularity in normal loading range and overloading range are just opposite, but anyone has good linear relationship. To observe the influence of pH on MFC electrical signal feedback experiments, we test the signal feedback regularity under different pH range, which was found everyone has different properties. According to the change regularity, the pH is divided into three parts:pH 7.2-6.8 stage, pH 6.7-5.8 stage, pH 5.7-4.0 stage.To research the change of MFC’s electric signal relative influent organic loading, the response time and response symbols of MFC’s electric signal were observed. Experiment result shows the response time was 4-6h, and response symbols were various with UASB under a variety of operating conditions. Within the scope of the normal organic loading, response time and response symbols can be sure from three stages when the system was operated with the increasing of intermittent loading. As the response time and symbols can be decided from two stage, when the system was under overloading operation and intermittent operation with the decreasing organic loading and continuous operation with increasing or decreasing organic load.The electric signal of MFC shows excellent feedback performance. However, the results show that, feedback performance of MFC’s voltage get unstable gradually after repeated acidification under the normal loading, and the value of MFC’s voltage decreases with the increasing of acidification frequency rapid acidizing.