title: On-line NIR monitoring during anaerobic treatment of municipal solid waste.
abstract: An anaerobic digester (81) was fed with the organic fraction of municipal solid waste and monitored intermittently for two years with on-line near-infrared (NIR) spectroscopy and traditional chemical parameters analysed off-line. The dynamics that occurred due to changes in substrate composition (changed C:N ratio) and changes in operating conditions (overloading) could be followed using principal component analysis of the obtained NIR-spectra. In addition, process disturbances such as failed stirring and increased foaming were readily detected by the NIR-spectra. Using PLS regression the propionate concentration could be predicted in the range 0.1-3.6 g/l, RMSEP 0.53 g/l with slope 0.74 and correlation coefficient 0.85. The response on changes in the digester fluid was reproducible and could be detected within 2.5 minutes, which can be considered as real-time monitoring.
authors.affiliation: Swedish Institute of Agricultural and Environmental Engineering, PO Box 7033, SE-750 07 Uppsala, Sweden. mikael.hansson@jti.slu.se
authors.forename: M
authors.initials: M
authors.lastname: Hansson
authors.forename: A
authors.initials: A
authors.lastname: Nordberg
authors.forename: B
authors.initials: B
authors.lastname: Mathisen
mesh_terms: D001331:Automation; D001421:Bacteria, Anaerobic; D019149:Bioreactors; D004784:Environmental Monitoring / Q000379:methods*; D012037:Refuse Disposal / Q000379:methods*; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared