Optimization of biomethane production by anaerobic co-digestion of food waste with cow dung
- Authors: Empompo, Jonathan Bambokela , Mayala, Glodi Niangi , Matheri, Anthony Njuguna , Muzenda, Edison , Belaid, Mohammed
- Date: 2017
- Subjects: Anaerobic co-digestion , Anaerobic monodigestion , Biomethane
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/364987 , http://hdl.handle.net/10210/250680 , uj:26127 , Citation: Empompo, J.B. et al. 2017. Optimization of biomethane production by anaerobic co-digestion of food waste with cow dung. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
- Description: Abstract: The world today is in a constant quest of generating clean energy which would considerably reduce the emission of greenhouse gas (GHG) for better living conditions. In this study, a comparative analysis between anaerobic mono-digestion and anaerobic co-digestion of food waste (FW) was conducted based on the following parameters; pH, carbon to nitrogen (C/N) ratio, total solids (TS) and volatile solids (VS) content. For anaerobic monodigestion FW alone was used as the substrate while for anaerobic co-digestion, two mixing ratios of FW with cow dung were used (2:1 and 1:2 respectively). Three digesters of 500 ml were used and placed into a water bath at 45°C through a Biochemical Methane Potential (BMP) Test using the Automatic Methane Potential Test System II (AMPTS II). The anaerobic mono-digestion of FW yielded 405.1 Nml of biomethane while the anaerobic co-digestion of FW with cow dung yielded 267.4 and 274.8 Nml at 2:1 and 1:2 mixing ratios correspondingly. The anaerobic co-digestion showed a significant decrease in the specific biogas production by 32.16 to 33.99% in comparison to anaerobic monodigestion. It was observed that the pH (7.21), C/N (31.41), TS (14.64%) and VS/TS (94.4%) of anaerobic mono-digestion of FW fell approximately and within their respective optimum range, 6.5 – 7.5, 15 – 30, 15 – 20% and 82.4 – 95.3%. Hence, it produced the best biomethane yield. The objective of this study was to prove that anaerobic co-digestion of FW with cow dung would produce an improved biogas yield as compared to anaerobic monodigestion.
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Green energy (biomethane) production from codigestion of abattoir, market and grass waste as substrates
- Authors: Matheri, Anthony Njuguna , Mwiinga, Masonga Sichibanze , Zelda, Rasmeni Zenzile , Mohamed, Belaid
- Date: 2019
- Subjects: Biogas , Biomethane , Digestion
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/402179 , uj:33645 , Citation: Matheri, A.N. et al. 2019. Green energy (biomethane) production from codigestion of abattoir, market and grass waste as substrates.
- Description: Abstract: South Africa had in the past years been experiencing an increased energy demand. High energy crisis called for research and development in a quest for alternative energy sources (waste to energy) that drive the Nation economy forward in line with Sustainable and National development goals. Utilizing organic waste to produce biogas as a source of energy could significantly help alleviate this problem. Biogas is renewable energy, a mixture primarily consisting of methane (CH4) and carbon dioxide (CO2). The study evaluated mono-digestion of market waste (MW), abattoir waste (AW), and grass (G) and co-digestion of the three mix of substrate by determining their biomethane potential under mesophilic conditions of 37oC. It was found that the mono-digestion of grass produced high methane (1035.3 Nml) after the stipulated 14 days of hydraulic retention time, Abattoir waste, and market waste produced 722.1 Nml and 470.7 Nml of methane respectively, and the co- digestion of all substrates produced 1013.1 Nml of methane after 14 days. Co-digestion of the substrates assisted to regulate the anaerobic digestion condition or variables for biomethane production. Co-digestion of the substrate was recommended for optimality or increase in methane yield.
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Sludge to energy recovery dosed with selected trace metals additives in anaerobic digestion processes
- Authors: Matheri, Anthony Njuguna , Ntuli, Freeman , Ngila, Jane Catherine
- Date: 2020
- Subjects: Additive , Anaerobic digestion , Biomethane
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/460010 , uj:40920 , Citation: Matheri, A.N., Ntuli, F. & Ngila, J.C. 2020. Sludge to energy recovery dosed with selected trace metals additives in anaerobic digestion processes.
- Description: Abstract: The energy demand is ever rising with population increase and technology evolution. Coal consumption in South Africa is estimated to be 86% of the total energy demand. It has a high magnitude of environmental pollution and contributes to climate change. This calls for cleaner, reliable, sustainable, decarbonized, decentralized, affordable, digitized with the diversification of energy mix. The study aimed at investigating the impact of dosing selected trace metals (Ni, Co, Cu) as an additive to the substrate in the sludge to energy recovery using anaerobic processes. Sewage sludge and cellulose were used as a substrate. The biomethane potential study was carried from a 500 ml batch automated bio-digester at a mesophilic temperature of 37oC and a substratum-to-inoculum ratio (2:1) of the organic load rate. The dosed micro-nutrients acted as microbial-agents responsible for the anaerobic digestion of the feedstock. Cellulose and sludge at 0.25 mg/L (Ni) recorded the highest production of the biomethane. Cellulose inoculated with cobalt had better biomethane production at 0.02 mg/L until 0.05 mg/L. High production of biomethane was observed at the substrate with a copper concentration of 4.5 mg/L. Adding trace metals to microbial cell surroundings stimulated microbial activity and prevented the accumulation of the fatty acids. However, high concentrations beyond threshold resulted in inhibition, toxicity to the microbial-growth, which was reflected in the reduction of the production of biomethane.
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