title: Optimization of solid state anaerobic digestion of the OFMSW by digestate recirculation: A new approach.
abstract: Dry anaerobic digestion (AD) of OFMSW was optimized in order to produce biogas avoiding the use of solid inoculum. Doing so the dry AD was performed irrigating the solid waste with liquid digestate (flow rate of 1:1.18-1:0.9 w/w waste/digestate; 21d of hydraulic retention time - HRT) in order to remove fermentation products inhibiting AD process. Results indicated that a high hydrolysis rate of organic matter (OM) and partial biogas production were obtained directly during the dry AD. Hydrolysate OM was removed from digester by the percolate flow and it was subsequently used to feed a liquid anaerobic digester. During dry AD a total loss of 36.9% of total solids was recorded. Methane balance indicated that 18.4% of potential methane can be produced during dry AD and 49.7% by the percolate. Nevertheless results obtained for liquid AD digestion indicated that only 20.4% and 25.7% of potential producible methane was generated by adopting 15 and 20 days of HRT, probably due to the AD inhibition due to high presence of toxic ammonia forms in the liquid medium.
authors.affiliation: Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano, Italy. Electronic address: michele.pognani@unimi.it.
authors.forename: Pognani
authors.initials: P
authors.lastname: Michele
authors.affiliation: Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano, Italy; Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi, Italy. Electronic address: giuliana.dimporzano@unimi.it.
authors.forename: D'Imporzano
authors.initials: D
authors.lastname: Giuliana
authors.affiliation: Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia, Italy. Electronic address: carlo.minetti@a2a.eu.
authors.forename: Minetti
authors.initials: M
authors.lastname: Carlo
authors.affiliation: Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia, Italy. Electronic address: sergio.scotti@a2a.eu.
authors.forename: Scotti
authors.initials: S
authors.lastname: Sergio
authors.affiliation: Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano, Italy; Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi, Italy. Electronic address: farbrizio.adani@unimi.it.
authors.forename: Adani
authors.initials: A
authors.lastname: Fabrizio
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D006868:Hydrolysis; D008697:Methane / Q000096:biosynthesis*; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D062611:Solid Waste / Q000032:analysis*
chemical_list: D056804:Biofuels; D062611:Solid Waste; D008697:Methane
keywords: Anaerobic digestion; Digestate; Irrigation; Methane; Organic fraction of municipal solid waste (OFMSW); Solid state fermentation