Charred fermentation residues accelerate methanogenesis and sorb air pollutants

Utilization of fermentation residues burdens management of many biogas stations. Its incorporation into arable land remains the most common practice despite the application cost are about the same to fertilization benefits, notwithstanding risk of soil crust formations and linked degradation of soil’s ability to retain water, transfer of knapweed seeds, and soil acidification. Two alternatives that deal with fermentation residues that were previously dewatered and pyrolysed were analyzed. Regarding the first alternative, the dust from charred residues was incorporated back into the feedstock of biogas station. The second alternative analyzed application of the dusty char as a wall finisher in building interiors. It was found that incorporation of charred residues into the feedstock that enters the anaerobic fermentation accelerates the biogas production thanks to increase of reaction surface and improves the stability of the fermentation process because of its pH and buffering capacity. Concerning the wall surface alternative, it was also confirmed that the charred residues improve the indoor welfare thanks to its sorption capacity that captures wide portfolio of air pollutants.