title: Use of near infrared spectroscopy in monitoring of volatile fatty acids in anaerobic digestion.
abstract: Recently biogas production from agricultural sources has rapidly developed. Therefore the demands on biogas plants to optimise the efficiency of the anaerobic digestion (AD) process have grown immensely. At present there is no online-supervision tool available to monitor the AD process, but costly and time-consuming chemical analyses are necessary. The possibility to use near-infrared spectroscopy (NIRS) in order to track relevant process parameters like total volatile fatty acids (VFA), acetic acid and propionic acid was investigated in the present research project. A NIR-sensor was integrated into a full-scale 1 MW biogas plant and NIR-spectra of the fermenter contents were recorded semi-continuously for 500 days. Weekly samples were taken and analysed for the above mentioned parameters. Calibration models were calculated, capable of following these parameters: VFA (r(2)=0.94), acetic acid (r(2)=0.69), propionic acid (r(2)=0.89).
authors.affiliation: Institute of Agricultural Engineering, Christian-Albrechts-University Kiel, Max-Eyth-strasse 6, 24118 Kiel, Germany. fjacobi@ilv.uni-kiel.de
authors.forename: H Fabian
authors.initials: HF
authors.lastname: Jacobi
authors.forename: Christian R
authors.initials: CR
authors.lastname: Moschner
authors.forename: Eberhard
authors.initials: E
authors.lastname: Hartung
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D001331:Automation; D001674:Bioelectric Energy Sources; D019149:Bioreactors; D002138:Calibration; D004867:Equipment Design; D005227:Fatty Acids / Q000737:chemistry; D005232:Fatty Acids, Volatile / Q000737:chemistry*; D005285:Fermentation; D005740:Gases; D010944:Plants / Q000378:metabolism; D011422:Propionates / Q000737:chemistry; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013997:Time Factors; D003313:Zea mays
chemical_list: D005227:Fatty Acids; D005232:Fatty Acids, Volatile; D005740:Gases; D011422:Propionates; C029658:propionic acid; D019342:Acetic Acid