S Riggio1, M Torrijos2, R Debord3, G Esposito4, E D van Hullebusch5, J P Steyer6, R Escudié7. 1. LBE, INRA, 102 avenue des Etangs, 11100 Narbonne, France; Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio, 43, 03043 Cassino, FR, Italy; Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454 Marne-la-Vallée, France. Electronic address: silvio.riggio@supagro.inra.fr. 2. LBE, INRA, 102 avenue des Etangs, 11100 Narbonne, France. Electronic address: michel.torrijos@supagro.inra.fr. 3. Naskeo Environnement, 52 rue Paul Vaillant Couturier, 92240 Malakoff, France. Electronic address: romain.debord@naskeo.com. 4. Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio, 43, 03043 Cassino, FR, Italy. Electronic address: giovanni.esposito@unicas.it. 5. Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454 Marne-la-Vallée, France. Electronic address: Eric.vanHullebusch@univ-paris-est.fr. 6. LBE, INRA, 102 avenue des Etangs, 11100 Narbonne, France. Electronic address: jean-philippe.steyer@supagro.inra.fr. 7. LBE, INRA, 102 avenue des Etangs, 11100 Narbonne, France. Electronic address: renaud.escudie@supagro.inra.fr.
Abstract
Spent animal bedding is a valuable resource for green energy production in rural areas. The properties of six types of spent bedding collected from deep-litter stables, housing either sheeps, goats, horses or cows, were compared and their anaerobic digestion in a batch Leach-Bed Reactor (LBR) was assessed. Spent horse bedding, when compared to all the other types, appeared to differ the most due to a greater amount of straw added to the litter and a more frequent litter change. Total solids content appeared to vary significantly from one bedding type to another, with consequent impact on the methane produced from the raw substrate. However, all the types of spent bedding had similar VS/TS (82.3-88.9)%, a C/N well-suited to anaerobic digestion (20-28, except that of the horse, 42) and their BMPs were in a narrow range (192-239NmLCH4/gVS). The anaerobic digestion in each LBR was stable and the pH always remained higher than 6.6 regardless of the type of bedding. In contrast to all the other substrates, spent goat bedding showed a stronger acidification resulting in a methane production lag phase. Finally, spent bedding of different origins reached, on average, (89±11)% of their BMP after 60days of operation. This means that this waste is well-suited for treatment in LBRs and that this is a promising process to recover energy from dry agricultural waste.
Spent animal bedding is a valuable resource for green energy production in rural areas. The properties of six types of spent bedding collected from deep-litter stables, housing either sheeps, n class="Species">goats, horses or cows, were compared and their anaerobic digestion in a batch Leach-Bed Reactor (LBR) was assessed. Spent horse bedding, when compared to all the other types, appeared to differ the most due to a greater amount of straw added to the litter and a more frequent litter change. Total solids content appeared to vary significantly from one bedding type to another, with consequent impact on the methane produced from the raw substrate. However, all the types of spent bedding had similar VS/TS (82.3-88.9)%, a C/N well-suited to anaerobic digestion (20-28, except that of the horse, 42) and their BMPs were in a narrow range (192-239NmLCH4/gVS). The anaerobic digestion in each LBR was stable and the pH always remained higher than 6.6 regardless of the type of bedding. In contrast to all the other substrates, spent goat bedding showed a stronger acidification resulting in a methane production lag phase. Finally, spent bedding of different origins reached, on average, (89±11)% of their BMP after 60days of operation. This means that this waste is well-suited for treatment in LBRs and that this is a promising process to recover energy from dry agricultural waste.