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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/SWMR/04
Enhancement of biogas production from farmyard manure and food waste through
inoculation and accelerants

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Mazhar Hussain , Yasir Abbas , Shahid Mumtaz , Ghulam Mustafa Shah , Hafiz Faiq
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Sadique Gul bakht , Muhammad Tahir , Muhammad Imran
1 COMSATS University Islamabad, Vehari Campus
Correspondence: mazhar6268261@gmail.com
Abstract
Biogas manufacturing through anaerobic decomposition of food waste (FW) co-digested with
farmyard manure (FYM) is a well-known technology. The anaerobic decomposition process
which is operated by a group of anaerobic microbes present in the FYM, the strength of these
anaerobic microbes is reduced in FYM due to their sensitivity to air and light once the animal
waste is discharged to ambient environment. Therefore, to enhance biogas production,
inoculation of intestinal waste (IW) of ruminant animals with abundance of anaerobic bacteria
is crucial. Objectives of this research are (i) to figure out the potential of FYM and FW alone
or in combination for biogas production, (ii) to determine the role of inoculum and accelerants
in mono- and co-digestion of FYM and FW. To explore the objectives, study was carried out
by conducting two batch scale experiments under mesophillic condition (37 ± 1 ◦C). In
experiment 1, effect of inoculum (obtained from slaughterhouse waste) on biogas production
from sole and co-digestion of food waste and farmyard manure was investigated. In experiment
2, role of the flyash and biochar as accelerants on biogas enhancement was studied. Results
revealed 94-113% greater biogas yield from co-digestion of FW and FYM as compared to their
mono-digestion. Application of intestinal waste further increased the biogas yield from the co-
digestion by 13%. Addition of fly ash as an accelerant to this optimized treatment
(FW+FYM+Inoculum) at a rate of 1, 2 and 3% on weight basis enhanced the biogas production
by 22, 25, and 27% as compared to the control. The respective increments in case of corn
biochar were 39, 41 and 35%. Overall, biogas production was greater between days 3 to day
15 and declined later with the experimental period. This can be linked with experiment pH
which plays an important role. The operational pH affects the digestive progress and products
directly. The ideal pH range for AD has been reported to be 6.8–7.4 the pH decreases in first 5
days due to hydrolysis, acidogenesis and acetogenesis process and then pH increases due to
methogenesis process and approach between 7 to 8. Overall, and for the reasons detailed above,
we conclude that co-digestion of FYM and FW increased biogas production as compared to
their sole digestion. Addition of inoculum from slaughterhouse waste further increased the
biogas production from co-digestion of FYM and FW. The best combination to maximize the
biogas yield is to add flyash at 2% in the co-digestion of FYM, FW and Inoculum.
Keywords: Food waste, Farmyard manure, Anaerobic-co-digestion, Intestinal waste inoculum,
Fly-ash and biochar accelerants

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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