Green energy from different feedstock processed under anaerobic conditions
¹Aleksandras Stulginskis University, Faculty of Forest Sciences and Ecology, Institute of Environment and Ecology, Studentų Str. 11, LT53361 Akademija, Kauno district, Lithuania; *Correspondence: virginija.skorupskaite@asu.lt
²Vėžaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry, Gargždų str. 29, LT96216 Vezaiciai, Klaipėda district, Lithuania
³Klaipėda University, Faculty of Marine Technology, Department of technological process. Herkaus Manto Str. 84, LT92294 Klaipėda, Lithuania
Abstract:
The possible use of energy crops and aquaculture for bioenergy production has only recently become a research target, so there is little information on their properties and advantages. The aim of this study was to investigate the possible use of cup plant, as well as marine and freshwater algae (Scenedesmus sp. and Chlorella sp.) for biogas production. Research of a batch anaerobic digestion process at a mesophilic temperature were performed using wet wastewater sludge, cattle manure, fresh microalgae biomass and dry marine algae, cup plant biomass and mixtures of these materials. The highest biogas yield (541.28 ml g-1 VS) was obtained by using a new feedstock from the microalgae Scenedesmus sp. biomass. That yield was 1.4 times higher than the biogas yield from cattle manure and 15% lower than the biogas yield from wastewater sludge. It was found that adding microalgae biomass to a cattle manure substrate increases biogas production approx. 1.5 times. The highest methane concentration in biogas produced from microalgae ranges from 64.87% to 66.66% and exceeds the methane amount (64.26%) in biogas produced from wastewater sludge. The methane amount in biogas produced from cattle manure, cup plant and marine algae biomass is lower than 60%. In addition, it was found that it is possible to produce 5,092.3 m3 of biogas or 113 GJ of energy from 1 ha of harvested cup plant biomass.
Key words:
biogas production, cattle manure, cup plant, marine algae, microalgae, wastewater sludge.