Enhanced mesophilic anaerobic digestion of food waste by thermal pretreatment: Substrate versus digestate heating.
Food waste (FW) represents a source of high potential renewable energy if properly treated with anaerobic digestion (AD). Pretreating the substrates could yield a higher biomethane production in a shorter time. In this study, the effects of thermal (heating the FW in a separate chamber) and thermophilic (heating the full reactor content containing both FW and inoculum) pretreatments at 50, 60, 70 and 80°C prior to mesophilic AD were studied through a series of batch experiments. Pretreatments at a lower temperature (50°C) and a shorter time (<12h) had a positive effect on the AD process. The highest enhancement of the biomethane production with an increase by 44-46% was achieved with a thermophilic pretreatment at 50°C for 6-12h or a thermal pretreatment at 80°C for 1.5h. Thermophilic pretreatments at higher temperatures (>55°C) and longer operating times (>12h) yielded higher soluble chemical oxygen demand (CODs), but had a negative effect on the methanogenic activity. The thermal pretreatments at the same conditions resulted in a lower solubilization of COD. Based on net energy calculations, the enhanced biomethane production is sufficient to heat up the FW for the thermal, but not for the thermophilic pretreatment.
Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio, 43, 03043 Cassino, FR, Italy. Electronic address: jaka@unicas.it.
Javkhlan
J
Ariunbaatar
Telematic University Pegaso, Piazza Trieste e Trento, 48, 80132 Naples, Italy.
Antonio
A
Panico
Department of Civil and Environmental Engineering, University of South Florida, 4204 E. Fowler Avenue, Tampa, FL 33620, USA.
Daniel H
DH
Yeh
Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio, 21, 80125 Naples, Italy.
Francesco
F
Pirozzi
UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands.
Piet N L
PN
Lens
Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio, 43, 03043 Cassino, FR, Italy.
Giovanni
G
Esposito
D000693:Anaerobiosis; D019149:Bioreactors; D005735:Garbage; D006358:Hot Temperature; D008697:Methane / Q000032:analysis*; D059205:Renewable Energy
D008697:Methane
Anaerobic digestion; Conventional thermal pretreatment; Energy requirement; Food waste; Thermophilic pretreatment