title: Online estimation of VFA, alkalinity and bicarbonate concentrations by electrical conductivity measurement during anaerobic fermentation.
abstract: This paper describes the use of electrical conductivity for measurement of volatile fatty acids (VFA), alkalinity and bicarbonate concentrations, during the 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 (AD) of vinasses producing methane. In the hydrogen production process, the total VFA concentration, but not bicarbonate concentration, was well estimated from the on-line electrical conductivity measurements with a simple linear regression model. In the methane production process, the bicarbonate concentration and the VFA concentration were well estimated from the simultaneous on-line measurements of pH and electrical conductivity by means of non-linear regression with neural network models. Moreover, the total alkalinity concentration was well estimated from electrical conductivity measurements with a simple linear regression model. This demonstrates the use of electrical conductivity for monitoring the AD processes.
authors.affiliation: Université de Toulouse, Toulouse, France.
authors.forename: Cesar-Arturo
authors.initials: CA
authors.lastname: Aceves-Lara
authors.forename: Eric
authors.initials: E
authors.lastname: Latrille
authors.forename: T
authors.initials: T
authors.lastname: Conte
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Steyer
mesh_terms: D000693:Anaerobiosis; D001639:Bicarbonates / Q000032:analysis*; D004553:Electric Conductivity; D005232:Fatty Acids, Volatile / Q000032:analysis*; D005285:Fermentation; D006859:Hydrogen / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008697:Methane / Q000302:isolation & purification; D010865:Pilot Projects
chemical_list: D001639:Bicarbonates; D005232:Fatty Acids, Volatile; D006859:Hydrogen; D008697:Methane