title: Effect of ultrasonication on anaerobic degradability of solid waste digestate.
abstract: This paper evaluates the effect of ultrasonication on anaerobic biodegradability of lignocellulosic residues. While ultrasonication has been commonly applied as a pre-treatment of the feed substrate, in the present study a non-conventional process configuration based on recirculation of sonicated digestate to the biological reactor was evaluated at the lab-scale. Sonication tests were carried out at different applied energies ranging between 500 and 50,000kJ/kg TS. Batch anaerobic digestion tests were performed on samples prepared by mixing sonicated and untreated substrate at two different ratios (25:75 and 75:25 w/w). The results showed that when applied as a post-treatment of digestate, ultrasonication can positively affect the yield of anaerobic digestion, mainly due to the dissolution effect of complex organic molecules that have not been hydrolyzed by biological degradation. A good correlation was found between the CH4 production yield and the amount of soluble organic matter at the start of digestion tests. The maximum gain in biogas production was 30% compared to that attained with the unsonicated substrate, which was tentatively related to the type and concentration of the metabolic products.
authors.affiliation: Dept. Civil and Environmental Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: Boni
authors.affiliation: Dept. Civil and Environmental Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: D'Amato
authors.affiliation: Dept. Civil and Environmental Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Polettini
authors.affiliation: Dept. Civil and Environmental Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Pomi
authors.affiliation: Dept. Civil and Environmental Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy. Electronic address: andreina.rossi@uniroma1.it.
authors.forename: A
authors.initials: A
authors.lastname: Rossi
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels; D005502:Food; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry; D008697:Methane / Q000096:biosynthesis; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry; D062611:Solid Waste; D014465:Ultrasonics / Q000379:methods*
chemical_list: D056804:Biofuels; D012722:Sewage; D062611:Solid Waste; C036909:lignocellulose; D008031:Lignin; D008697:Methane
keywords: Anaerobic digestion; Biomethane; Digestate treatment; Hydrolysis; Lignocellulosic waste; Sonication