Studies of Organic Matter in Composting, Vermicomposting, and Anaerobic Digestion by 13C Solid-State NMR Spectroscopy

Composting, vermicomposting, and anaerobic digestion are three commonly applied processes for the transformation of organic waste into valuable products for soil amendment. The application of compost, vermicompost, and digestate to soil requires specific properties, such as maturity and stability, strongly related to the composition of organic matter. C-13 solid-state Nuclear Magnetic Resonance (SSNMR) has often been applied to follow the transformation of organic matter during waste treatment processes, as well as to assess the quality of the produced amendments and the effectiveness of the treatments. Thanks to the possibility of associating the C-13 chemical shift to different functional groups of biomacromolecules present in the waste feedstocks and in the final products, thorough characterizations of organic matter have been performed exploiting C-13 cross-polarization magic angle spinning experiments, and semiquantitative descriptions of the evolution of the different groups during composting, vermicomposting and anaerobic digestion have been reported. Here, these studies are reviewed with the aim of highlighting the potential of the application of C-13 SSNMR to these complex materials, as well as the critical issues and perspectives.

Automated summary

Composting, vermicomposting, and anaerobic digestion are commonly used methods to convert organic waste into valuable soil amendment products. C-13 solid-state Nuclear Magnetic Resonance (SSNMR) has been applied to track the transformation of organic matter and evaluate the quality of the produced amendments and the effectiveness of the treatments.