Research Articles
Optimization of high solids batch anaerobic co-digestion of lignocellulosic biomass and cow dung under mesophilic temperature conditions
Authors:
A.L. Wickramaarachchi ,
University of Moratuwa, LK
About A.L.
Department of Chemical and Process Engineering
P.G. Rathnasiri,
University of Moratuwa, LK
M. Torrijos,
INRAE,Univ Montpellier, FR
R. Escudie,
INRAE,Univ Montpellier, FR
M. Narayana
University of Moratuwa, LK
Abstract
Anaerobic digestion is applied to recover energy from rice straw (RS) which is a lignocellulosic agricultural residue produced in huge quantities in Asia and Africa. Because of the high solids content of this feedstock, high solids anaerobic co-digestion in batch mode must be further investigated. In this study, optimal operating conditions for the anaerobic co-digestion of RS with cow dung (CD) in batch mode, with and without leachate recirculation, were assessed under mesophilic temperature conditions. Preliminary experiments carried out in 2 L batch reactors confirmed that the concentration of RS in the mixture of substrates S0 , in g VSRS/kg of mixture is an important parameter. Only batch reactors with the lowest So values (29 g VSRS/kg) produced biogas and rest of the reactors followed a long lag phase. The use of digestate from a previous batch as an inoculum was investigated with So values of 29 and 55 g VSRS/kg. Use of the digestate with So of 29 g VSRS/kg improved both initial degradation kinetics and the methane yield measured after 60 days. However, at So of 55 g VSRS/kg, the degradation kinetics were affected and after two months, 32 % of the biodegradable organic matter could not be eliminated. When leachate recirculation was performed in 6 L leach-bed reactors (LBRs) with So between 30 and 65 g VS lowest SRS/kg, the highest methane yield was recorded at the lowest So value. It can be concluded that under batch mode, an RS concentration around 30 g VSRS/kg may be recommended for industrial applications.
How to Cite:
Wickramaarachchi, A.L., Rathnasiri, P.G., Torrijos, M., Escudie, R. and Narayana, M., 2022. Optimization of high solids batch anaerobic co-digestion of lignocellulosic biomass and cow dung under mesophilic temperature conditions. Journal of the National Science Foundation of Sri Lanka, 50(1), pp.125–136. DOI: http://doi.org/10.4038/jnsfsr.v50i1.10358
Published on
10 Apr 2022.
Peer Reviewed
Downloads
