Cheap bioenergy from animal manure and straw
For years, researchers have sought to develop cost-effective green energy sources from low value substrates as an alternative to fossil fuels. The BIOMAN (Economically efficient biogas production from manure fibres and straw) project has moved the world closer to this goal with development of the reinjection loop concept. The technology developed under the auspices of BIOMAN was based on the reinjection loop concept. This technique is specifically directed at separated (manure) fibres, in order to open them up before reintroducing them into the anaerobic digester for biogas production by means of different technologies e.g. enzymatic and/or ultra sound. A survey was conducted to identify potentially available biomasses and their corresponding quantities. Based on the survey researchers selected eight biomass substrates with high lignocellulolytic content from a public databank. These substrates included green biomasses, different animal manure types and wheat straw. After chemical characterisation of the substrates, measurements were performed to assess their biomethane potential, BMP. The biomass substrates were analysed before and after tests on different separation equipment, different enzymatic treatments and ultrasound. The result was a technology that can be fitted to existing biogas plants running on manures and energy crops. In Germany, more than 6 000 biogas plants have been identified that may potentially benefit from investing in reinjection loop technology. Additional benefits include reduced costs for manure handling for farmers and compliance with EU environmental regulation. Biogasification of manures will also help in the conservation of nutrients with a degradable by-product, which can be used as a fertiliser and soil organic carbon enhancer. BIOMAN outcomes will make a significant contribution towards achieving the EU's ambitious greenhouse gas emission reduction targets. Furthermore, the renewable energy technology will also aid in the creation of more jobs and enhance Europe's competitiveness in the energy sector.
Keywords
Straw, bioenergy, BIOMAN, biogas, manure fibres, reinjection loop, biomass