The dynamics of an anaerobic digestion of crop substrates with an unfavourable carbon to nitrogen ratio.
The purpose of this study was to investigate the effects of the characteristics of basic crop substrates, such as the carbon, nitrogen, ash and volatile fatty acids contents, on the dynamics of the anaerobic digestion process. For this purpose, the stepwise anaerobic digestion of silage from six different plant species was carried out. Scaled probability distributions (log-normal, log-logistic, logistic, Weibull and Gompertz) were used to approximate the cumulative methane production curves obtained. The results indicated that the Gompertz distribution best fit the process. The hazard function of the Gompertz distribution was used to describe the process change dynamics. Ridge regression models were made and tested to clarify the impact of the crop properties on the distribution parameters. The analysis results indicated that the initial rate of the process depended on the reactor acidity and that the nitrogen content of the substrate was a key factor that affected the process dynamics.
Department of Agricultural and Forest Engineering, Faculty of Production Engineering, Warsaw University of Life Sciences, Nowoursynowska Street 166, 02-787 Warsaw, Poland.
Michał
M
Piątek
Department of Agricultural and Forest Engineering, Faculty of Production Engineering, Warsaw University of Life Sciences, Nowoursynowska Street 166, 02-787 Warsaw, Poland. Electronic address: aleksander_lisowski@sggw.pl.
Aleksander
A
Lisowski
The Bohdan Dobrzański Institute of Agrophysics of the Polish Academy of Sciences in Lublin, Doświadczalna Street 4, 20-290 Lublin, Poland.
Agnieszka
A
Kasprzycka
Department of Anaesthesiology, Medical Centre for Postgraduate Education, Clinical Hospital Adam Gruca, CMKP, Konarskiego Street 13, 05-400 Otwock, Poland.
Barbara
B
Lisowska
D000693:Anaerobiosis; D056804:Biofuels; D019149:Bioreactors; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D018556:Crops, Agricultural / Q000737:chemistry / Q000382:microbiology; D005232:Fatty Acids, Volatile / Q000737:chemistry; D007700:Kinetics; D008697:Methane / Q000096:biosynthesis*; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry; D012044:Regression Analysis; D012820:Silage / Q000382:microbiology
D056804:Biofuels; D005232:Fatty Acids, Volatile; D002244:Carbon; D009584:Nitrogen; D008697:Methane
Anaerobic digestion; Hazard function; Process dynamics