Physico-chemical characterization of selected feedstocks as co-substrates for household biogas generation in Ghana

ABSTRACT

Substituting biogas for Liquefied Petroleum Gas (LPG) in households is a long-awaited sustainable solution for the increasing cost of energy and large amounts of household human-generated waste. Nevertheless, a study of the characteristics of feedstocks is essential to maximise their energy potential. Consequently, this study examined the physico-chemical properties of Human Excreta (HE), Food Leftovers (FLO), Kitchen Residue (KR) and Cow Dung (CD) of Ghanaian origin adhering to recommended standards. Results for volatile to total solid ratios (VS/TS) were 0.81 ± 0.001, 0.97 ± 0.001,0.89 ± 0.001 and 0.85 ± 0.001 for HE, FLO, KR and CD, respectively. The results showed that all feedstocks had high biodegradable content, making them desirable for biogas production. The carbon-to-nitrogen (C/N) ratios determined from the elemental compositions were 8.29 ± 0.09, 22.14 ± 0.26, 23.34 ± 0.25 and 26.19 ± 0.47 for HE, FLO, KR and CD, respectively. Although the C/N ratios for FLO, KR and CD were within the optimal range, that of HE was significantly low. With a mean alkalinity of 1219.67 ± 1.53, 630.00 ± 0.58, 590.00 ± 2.08 and 15,730.00 ± 6.00 mg CaCO₃ eq./L for HE, FLO, KR and CD, it was observed that only CD has the optimal alkalinity value for anaerobic digestion. This brings into perspective the need for co-digestion and the choice of potential co-substrates for household biogas production.

KEYWORDS:

• Anaerobic co-digestion
• biogas
• feedstock
• human excreta
• food waste
• biogas potential

Data availability statement

Data are available within the article or its supplementary materials.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Regional Water and Environmental Sanitation Centre Kumasi (RWESCK) at the Kwame Nkrumah University of Science and Technology (KNUST), Kumasi with funding from the Ghana Government through the World Bank under the Africa Centers of Excellence project.

Notes on contributors

Blissbern Appiagyei Osei-Owusu

Blissbern Appiagyei Osei-Owusu is an Environmental Sanitation and Waste Management PhD. Candidate at the Regional Water and Environmental Sanitation Centre, Kumasi (RWESCK), Department of Civil Engineering, KNUST.

Martina Francisca Baidoo

Dr. Martina Francisca Baidoo has been working in the Department of Chemical Engineering, KNUST since November, 2016. She has gained in-depth knowledge in catalysis and petrochemistry from the Norwegian University of Science and Technology. Her research interests include waste recycling and valorization, biofuels and biomaterials, catalysts and its application in different areas.

Richard Arthur

Professor Richard Arthur is the dean for the faculty of engineering at Koforidua Technical University, Ghana. His general research areas include biotechnology and resources management, application of remote sensing techniques for assessing potential bioenergy resources in developing countries, anaerobic digestion of agricultural residues and OFMSW, solid and liquid waste treatment, biomass conversion technologies, water quality and climate change. His current research interest looks at trace elements requirements and impact on anaerobic digestion; biogas production from water hyacinth and other aquatic plants; optimization and stabilization of full-scale biogas plants.

Sampson Oduro-Kwarteng

Professor Sampson Oduro-Kwarteng is the director for the Regional Water and Environmental Sanitation Centre, Kumasi (RWESCK), KNUST. He has 25 years of experience as a Civil, Water & Sanitation Engineer. He is a Full Professor in Water and Environmental Sanitation Engineering in the Civil Engineering Department at Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. He is involved in water and environmental sanitation designs, services and construction supervision including: design of small towns water supply systems; Water, Sanitation, Hygiene (WASH) training and community participatory learning and action; WASH Behavioral Change and Management Training; assessment of capacity of public and private sector firms involved in water and environmental sanitation; and feasibility studies and designs of water and environmental sanitation projects.