Impact of anaerobic digestion on organic matter quality in pig slurry

Claire-Emmanuelle Marcato (1) , Rabi Mohtar , Jean-Claude Revel (1) , Philippe Pouech , Mohamed Hafidi (2) , Agnès Maritchù Guiresse (1)

1 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
2 Equipe Ecologie Végétale, Sol et Environnement

Changes in pig slurry organic matter (OM) during anaerobic digestion (AD) were studied in a reactor to characterize OM evolution through AD. OM maturity and stability were evaluated using different biological and physico-chemical methods. Germination and growth chamber experiments revealed a higher maturity of digested slurry (DS) than raw slurry (RS). Soil incubations showed that DS was more stable than RS with a C-mineralization of 12.0 g CO2-C 100 g1 Corg after 49 days as compared to 17.6 g CO2-C100 g1 Corg. Biochemical fractionation showed a relative increase in stable compounds such as hemicellulose-like and lignin-like molecules. Fourier-transform infrared spectroscopy showed some changes in the chemical structures of OM with a reduction in the aliphatic chain, lipid and polysaccharide levels. A comparison between the evolution of OM during AD and the first weeks of a composting process showed almost identical changes. Finally a theoretical method called Fictitious Atomic-group Separation was applied to the elemental compositions of RS and DS. DS was less humified than RS and presented the properties of a fulvic acid, indicating that the observed stability in DS was mainly due to the biodegradation of the most labile compounds

Mots clés: Anaerobic digestion; Humic substances; Organic matter - Stability; Maturity -

Domaines: Biologie animale

Claire-Emmanuelle Marcato, Rabi Mohtar, Jean-Claude Revel, Philippe Pouech, Mohamed Hafidi, et al.. Impact of anaerobic digestion on organic matter quality in pig slurry. International Biodeterioration & Biodegradation, 2009, 6 (3), pp.260-266. ⟨10.1016/j.ibiod.2008.10.001⟩. ⟨hal-03571958⟩