Yield, fermentation kinetics and the role of quality properties of thatching reed (Phragmites australis) during discontinuous anaerobic fermentation

•The biogas yield of thatching reed varied between 254.7 and 551.5 lN kgODM−1.•The methane production was 144.1–311.4 lN kgODM−1.•Biogas yield and process kinetics were influenced by lignin and nitrogen.•The energetic use of reed as an alternative exploitation method is conceivable.

Common reed is still used for a traditional way of roofing throughout the world. During the supply chain from reed harvester to thatcher, reed bunches of minor quality are excluded from further trading and disposed. Contrary to a conventional disposal, bunches could also be used for energetic purpose, but information on the use of thatching reed as biogas substrate is scarce. Therefore 50 customary reed bunches from different countries worldwide were analysed concerning chemical properties and performed discontinuous anaerobic fermentation with milled material according to VDI 4630. In addition to biogas and methane yields, we also characterised the kinetics of fermentation by fitting different sigmoid functions and selecting the best fitting function by the use of the Akaike Information Criterion and other fitting parameters. Subsequently the kinetic describing parameters maximum biogas production rate (vmax) and the moment of maximum production rate (tmax) were calculated. Influence of chemical properties on yields or fermentation kinetic parameters were analysed by Pearson product-moment correlation and Partial Least Squares Regressions (PLS).Biogas yields varied between 254.7 and 551.5 lN kgODM−1 with mean methane content of 56.6 ± 3.6%, as a function of recalcitrant lignin and nitrogen content (R2 = 0.816). Also vmax was highly influenced by these constituents (R2 = 0.732), whereas tmax showed only little correlation to chemical components.The study indicates a general suitability of B quality thatching reed for biogas production.Due to the contrary demands on the material for thatching and biogas production, the energetic use of reed as an alternative exploitation method is conceivable.