Co-composting of lignin to build up humic substances--Strategies in waste management to improve compost quality

摘要

Co-composting of different lignin sources with biogenic waste from the separate collection in Vienna was carried out in lab-scale experiments to promote humification as lignin is known to be a precursor molecule of humic substances. Humification is a target to be reached by composting due to the favorable properties for soils and plants. Extractable humic acids have been proved to be a suitable parameter to assess humification. Biogenic waste was used as a reference and basic material for co-composting of lignin. Lignin from different origins and composition was added: microbiologically degraded wood and lignin powder from industrial processes. Preliminary results show that addition of 2-5% of lignin powder could improve humic acid formation. Microbiologically degraded wood did not effect higher humic acid contents within the short time of lab-scale composting. Humic acid determination is based on photometrical investigations. To ensure that humic acid contents were not pretended by the presence of lignin, quality control was carried out using FT-IR spectroscopy and thermal analysis. The results obtained showed that lignin had been integrated in the humic acid molecule.