Evaluation of straw as a biofilm carrier in the methanogenic stage of two-stage anaerobic digestion of crop residues.
Straw was evaluated as a biofilm carrier in the methanogenic stage of the two-stage anaerobic digestion of crop residues. Three reactor configurations were studied, a straw-packed-bed reactor, a glass packed-bed reactor and a reactor containing suspended plastic carriers. The reactor with the packed straw bed showed the best results. It had the highest methane production, 5.4 11(-1) d(-1), and the chemical oxygen demand (COD) removal ranged from 73-50% at organic loading rates from 2.4-25 g COD l(-1) d(-1). The degradation pattern of volatile fatty acids showed that the degradation of propionate and longer-chain fatty acids was limiting at higher organic loading rates. A stable effluent pH showed that the packed-bed reactors had good ability to withstand the variations in load and volatile fatty acid concentrations that can occur in the two-stage process. The conclusion is that straw would work very well in the intended application. A further benefit is that straw is a common agricultural waste product and requires only limited resources concerning handling and cost.
Andersson
Jonatan
J
Department of Biotechnology, Lund University, Sweden.
Björnsson
Lovisa
L
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D018556:Crops, Agricultural / Q000737:chemistry*; D019605:Euryarchaeota / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D013548:Sweden
D005232:Fatty Acids, Volatile; D012722:Sewage; D008697:Methane