Biochar-Now

Project goals

The pyrolytic fixation of photosynthetically generated biomass to biochar is a process with a high technology readiness level to actively reduce CO₂ from the atmosphere. Biochar products from pristine sources are mainly used as an agricultural enhancer, where it acts, amongst other factors, as a source of nutrients and a means for enhanced retention of soil humidity, whereas the coal itself remains inert and leads to long-term storage of CO₂-derived carbon in soils. As a side effect, the pyrolysis process generates surplus energy, which can be used in a process chain for heating or electricity production. To significantly increase the possible extent of CO₂ drawdown with the biochar technique, we will explore the potential and limitations of biochar, generated from various organic-rich municipal waste streams, such as sewage sludge, particle board wood remains, other waste wood, compost sieve overflow etc. In addition to the upscaling of CO₂ removal from the atmosphere, this would commonly also have a positive effect on municipal waste management. The largest concern in terms of using waste feedstock relates to the potential presence of harmful pollutants and heavy metals in these materials. In the proposed project we will generate biochar from various waste streams, test whether the laboratory pyrolysis results can be upscaled to commercial pyrolysis reactors, analyze the organic and inorganic composition of the different waste-based biochars and evaluate their release potential for harmful pollutants and heavy metals under laboratory and more natural conditions using leaching experiments. To investigate the fate of waste-based biochars in soils, moreover, the interaction of biochar with microbial communities and their impact on the biochar chemistry and mobilization of harmful pollutants will be studied in detail. Using these results, we will evaluate upscaling-potential, feasibility, and likelihood of success for various potential source/application scenarios, leading to clear scientifically-based recommendations.