A novel microbial electrochemical sensor for on-line monitoring anaerobic biogradation processes

In anaerobic biodegradation systems, fermentative breakdown of monomers to volatile fatty acids (VFAs) and other simple and soluble metabolites happens with rapid kinetics. The monitoring of VFAs concentration in anaerobic digesters (AD) is crucial to prevent inhibition for organic overload and is usually performed manually by operators. The promptness of this response cannot be, thereby, immediate and preventing the inhibition of a digester might often be a question of few hours. The present work reports on an innovative type of Microbial Electrochemical Sensor (MES), integrated in AD with the purpose of on-line continuously monitor the microbial activity. Preliminary experiments were performed in lab-scale AD, fed in batch mode with four different types of fresh organic substrates. Real correlations between the electrical signal obtained by a MES and the concentrations of VFAs (as well as other physico-chemical parameters) were identified.