Effects of using green waste compost as a biological pre-treatment of lignocellulosic biomass to produce bioenergy

摘要

Biogenic residues, e.g., wheat straw, are gaining great interest for bioenergy production due to global climate change and competition between food and bioenergy markets. The biodegradability of straw is restricted due its high content of lignocellulose. Suitable pre-treatments need to be applied prior to producing bioenergy. This study investigated the effect of using compost as a natural source of microorganisms that are able to degrade lignocellulosic materials to produce methane. Wheat straw and compost were mixed and incubated at 21°C over 22 and 56 days. Methane production of straw (S), straw and compost without incubation time (SKR), straw and compost after 22 (SK_22T), and after 56 (SK_56T) days of incubation time were assessed. Results reveal methane yields from 222–265 L/kgVS - 261 L/kgVS S; 222 L/kgVS SKR; 265 L/kgVS SK_22T and 230 L/kgVS SK_56T. The microbial activity during the biological pre-treatment was low, which led to increases (at a lower level) in the methane production of SK_22T compared to S and SKR. Inhibitory substances might form after 22 days, since methane production was lower for SK_56T. As the pre-treated SK_22T produced the highest methane yield, the influence of temperature and the storage time at incubation should be further investigated.