(196f) GHG Credits: The Misunderstanding in the Lignocellulosic Case

In Colombia, one of the harvesting practices is to leave a part of the harvested residues on the field providing to the soil a percentage of the nutrients and organic matter required by the plant growth [1]. As a waste and organic matter are decomposed, the nutrients in excess (nitrogen, phosphorus and sulfur) are released into the soil to be used by plants (nutrient availability) [2]. Waste products produced by microorganisms contribute to the formation of the organic matter in soil which generates and provides the supplements for plant growth . Organic matter through its transformation provides the ability to author-recovery architecture soil that has been damaged. In addition to these agricultural practices, chemical fertilizers are provided to the soil to help to meet the needs in the balance of nutrients for the optimum crop growth [3]. However, when external nutrient sources as fertilizers are supplied to the soil, different side effects can take place. For instance, its regular use can deplete the soil reducing its porosity as well as contaminate underground water and contribute significantly to the green house gas (GHG) emissions. According to the research carried out, the GHG produced for the processing of agro-industrial wastes are low or zero. Although this assumption is completely wrong. In this work, two scenarios have been proposed. The first one considered the base case above described, when part of the harvesting residues are leaving on the field acting as a source for the nutrient balance in the soil. The second scenario considered the case when all the harvesting residues are retired from the field.

The aim of this work is to calculate the GHG emissions for the scenarios above proposed using the Life Cycle Assessment (LCA) methodology. For both cases, a gasification system based on the lignocellulosic residue processing was evaluated to produce electricity. For this study, the sugarcane case was analyzed The raw material was characterized by measuring moisture content (AOAC 928.09 method), klason lignin content (TAPPI 222 om-83 method), acid-soluble lignin content (TAPPI 250UM-85 method) holocellulose content (ASTM Standard D1104 method), cellulose content (TAPPI 203 os-74 method), ash content (TAPPI Standard T211 om-93 method), total nitrogen content (kjeldahl method), potash content (colorimetric method) and phosphorous content (colorimetric method). All the experiments were carried out in the Biotechnology and Agrobusiness Institute at the Universidad Nacional de Colombia at Manizales.

The results lead to conclude that for the second scenario the GHG emissions increase, due to the CO₂ capture by the crop is reduced because of the removing of all the harvesting residues from the field and it is not possible to reach the needs that the crop requires to growth optimally.

References

 [1]     S. R. Hughes and W. R. Gibbons, “Sustainable Multipurpose Biorefineries for Third-Generation Biofuels and Value-Added Co-Products, Biofuels - Economy, Environment and Sustainability.,” 2013.

[2]      P. Stille, A.-D. Schmitt, F. Labolle, M.-C. Pierret, S. Gangloff, F. Cobert, E. Lucot, F. Guéguen, L. Brioschi, M. Steinmann, and F. Chabaux, “The suitability of annual tree growth rings as environmental archives: Evidence from Sr, Nd, Pb and Ca isotopes in spruce growth rings from the Strengbach watershed,” Comptes Rendus Geosci., vol. 344, no. 5, pp. 297–311, May 2012.

[3]      L. Panichelli and E. Gnansounou, “Estimating greenhouse gas emissions from indirect land-use change in biofuels production: concepts and exploratory analysis for soybean-based biodiesel production.,” J. Sci. Ind. Res., vol. 67, pp. 1017–1030, 2008.