title: Effect of the concentration of essential oil on orange peel waste biomethanization: Preliminary batch results.
abstract: The cultivation of orange (Citrus×sinensis) and its transformation is a major industry in many countries in the world, it leads to the production of about 25-30Mt of orange peel waste (OPW) per year. Until now many options have been proposed for the management of OPW but although they are technically feasible, in many cases their economic/environmental sustainability is questionable. This paper analyse at lab scale the possibility of using OPW as a substrate for anaerobic digestion. Specific objectives are testing the possible codigestion with municipal biowaste, verifying the effect on methane production of increasingly high concentration of orange essential oil (EO, that is well known to have antioxidant properties that can slower or either inhibit biomass activity) and obtaining information on the behaviour of d-limonene, the main EO component, during anaerobic digestion. The results indicate that OPW can produce up to about 370LnCH4/kgVS in mesophilic conditions and up to about 300LnCH4/kgVS in thermophilic conditions. The presence of increasingly high concentrations of EO temporary inhibits methanogenesis, but according to the results of batch tests, methane production restarts while d-limonene is partially degraded through a pathway that requires its conversion into p-cymene as the main intermediate.
authors.affiliation: Università degli Studi Mediterranea di Reggio Calabria, Dipartimento di Ingegneria Civile, dell'Energia dell'Ambiente e dei Materiali, via Graziella, loc. Feo di Vito, 89122 Reggio Calabria, Italy. Electronic address: paolo.calabro@unirc.it.
authors.forename: P S
authors.initials: PS
authors.lastname: Calabrò
authors.affiliation: Università degli Studi di Napoli Federico II, Dipartimento di Ingegneria Civile, Edile e Ambientale, Via Claudio 21, 80125 Napoli, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Pontoni
authors.affiliation: Politecnico di Milano, DICA Dipartimento di Ingegneria Civile e Ambientale, Piazza L.da Vinci 32, 20133 Milano, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Porqueddu
authors.affiliation: Università degli Studi Mediterranea di Reggio Calabria, Dipartimento di Ingegneria Civile, dell'Energia dell'Ambiente e dei Materiali, via Graziella, loc. Feo di Vito, 89122 Reggio Calabria, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Greco
authors.affiliation: Università degli Studi di Napoli Federico II, Dipartimento di Ingegneria Civile, Edile e Ambientale, Via Claudio 21, 80125 Napoli, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pirozzi
authors.affiliation: Politecnico di Milano, DICA Dipartimento di Ingegneria Civile e Ambientale, Piazza L.da Vinci 32, 20133 Milano, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Malpei
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors; D032084:Citrus sinensis; D053138:Cyclohexenes / Q000737:chemistry; D000081007:Cymenes; D005638:Fruit; D005735:Garbage; D000077222:Limonene; D008697:Methane / Q000737:chemistry*; D039821:Monoterpenes / Q000737:chemistry; D009822:Oils, Volatile / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry*; D013729:Terpenes / Q000737:chemistry; D014835:Volatilization; D014866:Waste Products
chemical_list: D056804:Biofuels; D053138:Cyclohexenes; D000081007:Cymenes; D039821:Monoterpenes; D009822:Oils, Volatile; D010938:Plant Oils; D012722:Sewage; D013729:Terpenes; D014866:Waste Products; C007210:4-cymene; D000077222:Limonene; D008697:Methane
keywords: Anaerobic digestion; Limonene; Mesophilic conditions; Orange peel waste; Thermophilic conditions; p-Cymene