Co-Digestion of Napier Grass with Food Waste and Napier Silage with Food Waste for Methane Production

Suriyan Boonpiyo, Sureewan Sittijunda and Alissara Reungsang
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Suriyan Boonpiyo: Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand
Sureewan Sittijunda: Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom 73170, Thailand
Alissara Reungsang: Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand

Energies, 2018, vol. 11, issue 11, 1-13

Abstract: Enhancement of methane production by co-digestion of Napier grass and Napier silage with food waste was investigated in batch and repeated batch modes. First, the ratios of Napier grass to food waste and Napier silage to food waste were varied at different g-volatile solids (VS) to g-VS at an initial substrate concentration of 5 g-VS/L. The optimum ratios of Napier grass to food waste and Napier silage to food waste were 1:4 and 3:2 (g-VS/g-VS), respectively. This gave maximum methane yields (MY) of 411 and 362 mL-CH 4 /g-VS added , respectively. Subsequently, the suitable ratios were used to produce methane at various substrate concentrations. A maximal MY of 403 and 353 mL CH 4 /g-VS were attained when concentrations of Napier grass co-digested with food waste and Napier silage co-digested with food waste were 15 g-VS/L and 20 g-VS/L, respectively. Under the optimum substrate concentration, the maximum MY from co-digestion of Napier grass with food waste was 1.14 times higher than that of Napier silage with food waste. Thus, co-digestion of Napier grass with food waste was further investigated at various organic loading rates (OLRs) in a 10.25 L horizontal reactor with a working volume of 5 L at an optimal ratio of 1:4 (g-VS/g-VS) and substrate concentration of 15 g VS/L. An OLR of 1.5 g-VS/L?d gave a maximum methane production rate and MY of 0.5 L CH 4 /L?d and 0.33 L-CH 4 /g-VS added , respectively. Under the optimum OLR, the predominant methane producers were Methanoregula sp., Methanotorris sp., Methanobacterium sp., Methanogenium sp. and Methanosarcina sp. An energy production of 11.9 kJ/g-VS added was attained.

Keywords: biogas; anaerobic digestion; energy crop; municipal waste; lignocellulosic material; horizontal reactor; repeated batch (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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