Online estimation of VFA, alkalinity and bicarbonate concentrations by electrical conductivity measurement during anaerobic fermentation
Résumé
This paper describes the use of electrical conductivity for measurement the Volatile Fatty Acids (VFA) and bicarbonate concentrations, during anaerobic fermentation process. Two anaerobic continuous processes were studied: the first was a laboratory reactor for hydrogen production from molasses and the second was a pilot process for anaerobic digestion of vinasses producing methane. In case of hydrogen production process, the VFA concentration, but not bicarbonate concentration, can be estimated from the on-line electrical conductivity measurements. In case of methane production process, the bicarbonate concentration, but not the VFA concentration, can be estimated from the simultaneous on-line measurements of pH and electrical conductivity. That shows the interest of electrical conductivity for monitoring the anaerobic digestion processes.