Anaerobic digestion of autoclaved and untreated food waste.
Anaerobic digestion of autoclaved (160°C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids(VS)/m(3)d. Methane yields at all OLR were 5-10% higher for untreated FW (maximum 0.483±0.013 m(3) CH4/kg VS at 3 kg VS/m(3) d) than autoclaved FW (maximum 0.439±0.020 m(3) CH4/kg VS at 4 kg VS/m(3) d). The residual methane potential of both digestates at all OLRs was less than 0.110 m(3) CH4/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.
Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen, Finland. Electronic address: elina.tampio@mtt.fi.
Elina
E
Tampio
Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen, Finland.
Satu
S
Ervasti
Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen, Finland.
Teija
T
Paavola
University of Southampton, Faculty of Engineering and the Environment, Southampton SO17 1BJ, UK.
Sonia
S
Heaven
University of Southampton, Faculty of Engineering and the Environment, Southampton SO17 1BJ, UK.
Charles
C
Banks
Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen, Finland.
Jukka
J
Rintala
D000693:Anaerobiosis; D019149:Bioreactors; D004063:Digestion / Q000502:physiology*; D005502:Food; D008697:Methane / Q000096:biosynthesis*; D011312:Pressure; D012037:Refuse Disposal / Q000379:methods*; D013227:Steam; D014866:Waste Products / Q000032:analysis*
D013227:Steam; D014866:Waste Products; D008697:Methane
Anaerobic digestion; Autoclave treatment; Food waste; Nitrogen; Organic loading rate