Abstract
The stability of the methane fermentation process is highly dependent on the activity of methanogens. On-line monitoring of appropriate parameters is required in order to avoid process failure. NAD(P)H fluorescence is to detect the microbial metabolic state changes and a commercially probe designed to detect NAD(P)H has been developed. The use of NAD(P)H fluorescence probe to monitor the anaerobic digestion was evaluated. A laboratory scale anaerobic reactor was operated on synthetic medium with a substrate containing of either acetic acid or glucose at mesophilic temperature for the hydraulic retention time of 10-5 days. During start up, NAD(P)H fluorescence were highly unbalanced. After 32 days steady state was reached with a stable methane production. The response of NAD(P)H fluorescence were low and stable. Once the reactor was overloaded, an increase in acetate concentration and a decrease in methane production rate were observed. Acetic acid constituted the main part of the VFA concentration inhibited the growth of methanogens. After that the time lag NAD(P)H increased slowly. The result showed that these changes were related to the metabolic state in the reactor. It was suggested that NAD(P)H could be utilized for on-line monitoring of anaerobic digestion.HomePageKeywords: methane fermentation, methane production rate, NAD(P)H fluorescence probe, on-line monitoring, overload