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Sizing of an anaerobic biodigester for the organic fraction of municipal solid waste

- Kigozi, R., Aboyade, A. O., Muzenda, Edison

  • Authors: Kigozi, R. , Aboyade, A. O. , Muzenda, Edison
  • Date: 2014
  • Subjects: Anaerobic digestion , Biogas digesters , Clean energy , Municipal solid waste management
  • Type: Article
  • Identifier: uj:4982 , ISSN 2078-0966 , http://hdl.handle.net/10210/13114
  • Description: The anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) for biogas production is a potential solution to the growing challenges associated with municipal solid waste (MSW) management while simultaneously providing an alternative clean energy source. Biogas is produced by the anaerobic digestion (AD) of biomass using microorganisms in specifically designed plants called biogas digesters under controlled conditions or naturally in marshes and landfills. It is a rather clean and versatile fuel as opposed to fossil fuels. To design an efficient AD system, a proper understanding of the quality and quantity of available feedstock must be made as well as prevailing operating conditions. This paper represents steps that were taken to come up with an optimal size of biodigester to treat OFMSW produced at the University of Johannesburg’s Doornfontein Campus in downtown Johannesburg. The campus generates 232.2kg of OFMSW per day which required 30m3 of biodigester capacity.
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Biogas technology : current trends, opportunities and challenges

- Kigozi, R., Muzenda, Edison, Aboyade, A. O.

  • Authors: Kigozi, R. , Muzenda, Edison , Aboyade, A. O.
  • Date: 2014
  • Subjects: Anaerobic digestion , Biogas technology , Biomass
  • Type: Article
  • Identifier: uj:4984 , http://hdl.handle.net/10210/13116
  • Description: Biogas is the gaseous product of the biogenic fermentation of biomass. It has an approximate composition of 50-70% Methane (a combustible gas), 30-50% Carbon dioxide and other trace gasses depending on the nature of the biomass. It typically has a calorific value of 21–24 MJ/m3. Anaerobic digestion of biomass can artificially be achieved under controlled conditions in specifically designed plants known as anaerobic digesters or naturally at the bottom of marshes. Biogas, a versatile energy source can be used for heating, cooking, lighting, electricity and if purified further, it can be used as a vehicle fuel among other applications. The digestate is a widely sought after organic agricultural fertilizer. The first notable use of biogas technology dates back as far as 1859, there has been several advancements over the years in its application as well as production which are presented in this paper.
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A review of biogas production optimization from grass silage

- Muzenda, Edison, Sibiya, Noxolo

  • Authors: Muzenda, Edison , Sibiya, Noxolo
  • Date: 2014
  • Subjects: Biogas , Grass - Silage , Anaerobic digestion
  • Type: Article
  • Identifier: uj:5033 , http://hdl.handle.net/10210/13553
  • Description: Anaerobic digestion (AD) of organic materials offers an alternative source of renewable energy, as bio-methane has a potential to replace fossil fuels for energy production for heat and power, vehicular fuel and as well as valuable material recovery. In addition AD can address pollution problems by minimizing and utilizing biodegradable waste. This is a well-researched and technologically advanced technique with various successful small to large scale plants in the developed world. For developing countries, not much success has been reported due to operational and maintenance challenges, low biogas production and public perceptions among other several contributing factors. This paper reviews AD process optimization focusing on parameters such as temperature, pH, loading rate, hydraulic retention time and agitation. Several studies have shown optimum biogas production from grass in mesophilic, alkaline or neutral conditions at retention times of about 30 days. This review is the background and basis of our current work on optimizing biogas production from selected South African grass species.
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Environmental sustainability : multi-criteria decision analysis for resource recovery from organic fraction of municipal solid waste

- Masebinu, S. O., Akinlabi, Esther Titilayo, Muzenda, E., Mbohwa, Charles, Aboyade, A. O., Mahlatsi, T.

The kinetic of biogas rate from cow dung and grass clippings

- Matheri, Anthony Njuguna, Belaid, Mohammed, Seodigeng, Tumisang, Ngila, Catherine Jane

A review of biogas purification through chemical absorption

- Muzenda, Edison, Maile, Ireen

  • Authors: Muzenda, Edison , Maile, Ireen
  • Date: 2014
  • Subjects: Anaerobic digestion , Biogas purification , Chemical absorption
  • Type: Article
  • Identifier: uj:5041 , http://hdl.handle.net/10210/13561
  • Description: Biogas is an alternative source of energy which is produced by anaerobic digestion (AD) of waste materials. Biogas contains 50 -70% methane and 30-50% carbon dioxide as well as small a amounts of other gases with a calorific value of about 21-24 MJ/m3 . These trace components limit the usage of the biogas as they lower the calorific value of the gas and limit its commercialization. Hence, there is a need for purification and upgrading to meet specified application standards. The purification and upgrading processes can be classified into four major techniques which are absorption, adsorption, membrane separation and cryogenic separation. This review is focused on biogas enrichment through chemical absorption. This process involves amine washing with mono-,di- or tri-ethanolamine solutions, alkali washing with calcium oxide, calcium, potassium and sodium hydroxides, and synthesised ionic solutions of halide imidazolium ionic liquids. The regeneration of the spent chemicals for re-use will also be studied.
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Waste to energy bio-digester selection and design model for the organic fraction of municipal solid waste

- Matheri, Anthony Njuguna, Mbohwa, Charles, Ntuli, Freeman, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine, Njenga, Cecilia Kinuthia

Anaerobic digestion for sustainable energy : a brief review

- Kumba, Tresor K., Akinlabi, Esther Titilayo, Madyira, Daniel M.

Biochemical methane potential of OFMSW for City of Johannesburg

- Maile, Ireen, Muzenda, Edison, Mbohwa, Charles

  • Authors: Maile, Ireen , Muzenda, Edison , Mbohwa, Charles
  • Date: 2016
  • Subjects: Anaerobic digestion , Landfill , Methane potential
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/216566 , uj:21522 , Citation: Maile, I., Muzenda, E. & Mbohwa, C. 2016. Biochemical methane potential of OFMSW for City of Johannesburg.
  • Description: Abstract: The accumulation of Organic Fraction of Municipal Solid Waste (OFMSW) in landfills not only pose threat to the environment, it may also lead to potential health hazards. Anaerobic digestion stands a very good chance to mitigate this waste accumulation in landfills and has potential to create green jobs. BMP has been widely studied in anaerobic digestion for the production of sustainable energy. Bioprocess control Automatic Methane Potential Test System (AMPTS) II machine was used to set up the assays and run the tests. OFMSW was observed to have a low pH which affects the production process and biogas yield. Buffer solutions that were used in this study were calcium carbonate (CaCO3) and sodium hydroxide (NaOH). It was observed that CaCO3 not only stabilizes the pH but it also gives nutrients to the microbes and thus results in higher biogas yields. Inoculation also helped in stabilizing the process and improved the yield. The digester with CaCO3 resulted in a higher methane yield than the others. Though CaCO3 gave good results its use was discontinued as it has a negative impact on the environment. The BMP of OFMSW was found to be 200 ml CH4 / g VS. The methane content was found to be on average 58%.
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Bio-methane generation from organic waste : a review

- Muzenda, Edison

  • Authors: Muzenda, Edison
  • Date: 2014
  • Subjects: Anaerobic digestion , Biodegradable material , Biogas
  • Type: Article
  • Identifier: uj:4987 , ISSN 2078-0966 , http://hdl.handle.net/10210/13119
  • Description: Anaerobic digestion of organic waste can address both energy recovery and pollution control. A variety of agricultural, industrial and domestic wastes can be anaerobically digested as they contain easily biodegradable material. Biogas contains 50 -70% methane and 30-50% carbon dioxide as well as small a amounts of other gases with calorific value of about 21-24 MJ/m3. This paper reviews the history of biogas, biogas production stages and operating parameters. The anaerobic digestion configuration and potential substrates for biogas production are also considered.
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Economic evaluation of anaerobic digestion technology

- Sebola, M.R., Tesfagiorgis, H., Muzenda, E.

  • Authors: Sebola, M.R. , Tesfagiorgis, H. , Muzenda, E.
  • Date: 2016
  • Subjects: Anaerobic digestion , Energy recovery , Waste disposal
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/123236 , uj:20767 , Citation: Sebola, M.R., Tesfagiorgis, H. & Muzenda, E. 2016. Economic evaluation of anaerobic digestion technology.
  • Description: Abstract: This paper evaluates the viability of anaerobic digestion technology as a treatment process for organic waste with an intention of solving the landfill crisis as well as mitigation of greenhouse gases. The proposed technology consists of two digesters system using soaking as a pre-treatment method, and with recirculation of the process water and digested sludge. A financial model was developed to evaluate the economic feasibility of this technology as a renewable energy. Instead of the waste decomposing at local landfills, is converted into a source of energy while the by-products of the process are treated and used as fertilizers. This technology will require a capital investment of R 2, 2773,900 with a capacity to treat 730000 kg of waste annually. The annual production cost of R1, 269,138 was calculated. The proposed model has debt repayments of R 2,478,551. The total revenue from year 2 – 5 was R 2,360,800, R 2,930,158, R 3,457,314.6 and R 3,988,407.6, respectively. These AD facilities can produce up to 110960 kWh per annum of biogas fuel. The net present value of R3, 042,592, internal rate of return (IRR) of 33% and (BCR) of 1.96 shows that the technology is economically feasible.
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Effect of particle size on anaerobic digestion of different feedstocks

- Sebola, Mmabyalwa, Tesfagiorgis, Habtom, Muzenda, Edison

  • Authors: Sebola, Mmabyalwa , Tesfagiorgis, Habtom , Muzenda, Edison
  • Date: 2016
  • Subjects: Anaerobic digestion , Mesophillic batch digestion , Microbes
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/213700 , uj:21185 , Citation: Sebola, M., Tesfagiorgis, H & Muzenda, E. 2016. Effect of particle size on anaerobic digestion of different feedstocks.
  • Description: The speed and stability of anaerobic digestion depends mainly on the particle size of the input material. In this paper, particle sizes of 500μm, 250μm, 100μm and 25μm were investigated to evaluate the effects of particle size on biogas production and identify the most suitable size that would improve the efficiency of anaerobic digestion. The study was conducted using anaerobic digestion batch scale tests and gas chromatography to investigate the quality of the gas produced and the optimum particle size to maximise methane production. Prior digestion, the distributions of particle sizes of all samples were determined using single and double pass distribution techniques. 59%, 53%, 33% and 39% of CD, CM, PM and SW were recovered, respectively. In both techniques, the weight of the feed recovered reduced as the sieve became smaller. Decreasing the particle size of the feedstock significantly increased the amount of biogas. At 25μm particle size, 583ml, 569ml, 538ml and 398ml of methane was produced on the 4th day of gas production for CD, PM, CM and SW, respectively. At optimal particle size (25μm) methane was 3 – 30 % higher as compared to that of 100μm, 250μm and 500μm particle size in mesophillic batch digestion tests.
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Biogas production using the organic fraction of municipal solid waste as feedstock

- Kigozi, R., Aboyade, A., Muzenda, Edison

  • Authors: Kigozi, R. , Aboyade, A. , Muzenda, Edison
  • Date: 2013
  • Subjects: Anaerobic digestion , Biogas , Organic fraction of municipal solid waste
  • Type: Article
  • Identifier: uj:4900 , ISSN 2349-1442 , http://hdl.handle.net/10210/12995
  • Description: Biogas typically refers to an odourless gas produced by anaerobic digestion (AD) of biomass using microorganisms. It has an approximate composition of 70-50% Methane (a combustible gas), 30-50% Carbon dioxide and other trace gases depending on the nature of the biomass. The idea of using the organic fraction of municipal solid waste (OFMSW) or simply municipal biowaste as feedstock for biogas production represents an environmentally sustainable energy source since it improves solid waste management while simultaneously providing an alternative clean energy source. Among other applications, the gas can be used for heating, cooking and electricity generation. However, notwithstanding, OFMSW as a feedstock for AD comes with its own unique challenges compared to other forms of biomass. This paper therefore reviews the specific opportunities, challenges and techno-economics of using OFMSW as sole feedstock supply for biogas production.
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The role of trace elements on anaerobic codigestion in biogas production

- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine

Effect of temperature and pH on the anaerobic digestion of grass silage

- Sibiya, Noxolo T., Muzenda, Edison, Tesfagiorgis, Habtom B.

  • Authors: Sibiya, Noxolo T. , Muzenda, Edison , Tesfagiorgis, Habtom B.
  • Date: 2014
  • Subjects: Biogas , Anaerobic digestion , Grass - Silage , pH (Chemistry) , Anaerobic digestion - Effect of temperature on
  • Type: Article
  • Identifier: uj:5051 , http://hdl.handle.net/10210/13590
  • Description: The operating temperature and pH level in the digester during anaerobic digestion and the retention period are among the major factors that affect the rate of biogas production. Therefore, this paper evaluates the effects of temperature and pH in anaerobic digestion of grass silage. Grass silage was digested in 1000ml at different temperatures (35 ○C, 40 ○C, 45 ○C and 50 ○C) and pH (6.5, 6.8 &7.2). The digesters were shaken everyday to prevent the formation of surface crust which may prevent contact between microorganisms and the substrate. The characteristics of grass and cow dung and the optimal retention time are also reported. The results show that as the temperature was increased the biogas production and methane was also increased, however the high amount of biogas production rate and methane content was observed in the digester operated at 45 ○C and pH of 6.5. The process was carried out for 11days; however the optimal hydraulic retention time for digester that had high biogas was 8 days.
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Economic evaluation of anaerobic digestion technology

- Sebola, M.R., Tesfagiorgis, T., Muzenda, E.

  • Authors: Sebola, M.R. , Tesfagiorgis, T. , Muzenda, E.
  • Date: 2016
  • Subjects: Anaerobic digestion , Energy recovery , Waste disposal
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/213732 , uj:21189 , Citation: Sebola, M.R., Tesfagiorgis, T & Muzenda, E. 2016. Economic evaluation of anaerobic digestion technology.
  • Description: Abstract: This paper evaluates the viability of anaerobic digestion technology as a treatment process for organic waste with an intention of solving the landfill crisis as well as mitigation of greenhouse gases. The proposed technology consists of two digesters system using soaking as a pre-treatment method, and with recirculation of the process water and digested sludge. A financial model was developed to evaluate the economic feasibility of this technology as a renewable energy. Instead of the waste decomposing at local landfills, is converted into a source of energy while the byproducts of the process are treated and used as fertilizers. This technology will require a capital investment of R 2, 2773,900 with a capacity to treat 730000 kg of waste annually. The annual production cost of R1, 269,138 was calculated. The proposed model has debt repayments of R 2,478,551. The total revenue from year 2 – 5 was R 2,360,800, R 2,930,158, R 3,457,314.6 and R 3,988,407.6, respectively. These AD facilities can produce up to 110960 kWh per annum of biogas fuel. The net present value of R3, 042,592, internal rate of return (IRR) of 33% and (BCR) of 1.96 shows that the technology is economically feasible.
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Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings

- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Catherine Jane, Mbohwa, Charles

Optimization of Biogas Production from sewage sludge

- Belaid, Mohamed, Matheri, Anthony Njuguna, Lelosa, Itumeleng Constance, Muzenda, Edison, Ramatsa, Ishmael

Biochemical methane potential analysis using cow dung, chicken manure and pig manure under mesophilic conditions

- Belaid, Mohamed, Matheri, Anthony Njuguna, Mdluli, Nomkhosi Princess, Muzenda, Edison

  • Authors: Belaid, Mohamed , Matheri, Anthony Njuguna , Mdluli, Nomkhosi Princess , Muzenda, Edison
  • Date: 2019
  • Subjects: Anaerobic digestion , Mono-digestion , Co-digestion
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/403895 , uj:33863 , Citation: Belaid, M. et al. 2019. Biochemical methane potential analysis using cow dung, chicken manure and pig manure under mesophilic conditions.
  • Description: Abstract: In this study, we compared methane production by anaerobic mono-digestion and co-digestion of cow dung, chicken manure and pig manure under mesophilic conditions at the temperature of 37 0 C using a ratio of 1:1. C/N ratio, pH, VS/TS and sulphur content were the parameters investigated. Results indicated that co-digesting of cow dung; pig manure and chicken manure enhanced biogas production and methane content. The results also imply that pig manure cannot be used alone to produce methane as it produced low methane. Chicken manure produced more on the first day (272 Nml) compared to pig manure (257.4 Nml) and cow dung (80.5 Nml). On the ninth day, chicken produced 884 .9 Nml and then on the tenth day it went up again to 1095.6 Nml, reached its peak on day 13 and stopped, chicken yielded better results compared to the cow dung and pig manure because chicken had a higher VS/TS percent which is desirable for methane production. Pig manure started producing methane on the first day which was 257.4 Nml and stopped on the second day with the volume of 262.3 Nml. Pig manure showed poor results compared to cow dung and chicken manure.
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Determination of the potential impact of domestic Anaerobic Digester Systems: a community based research initiative in rural Bangladesh

- Rahman, Khondokar M., Melville, Lynsey, Edwards, David J., Fulford, David, Thwala, Wellington Didibhuku

  • Authors: Rahman, Khondokar M. , Melville, Lynsey , Edwards, David J. , Fulford, David , Thwala, Wellington Didibhuku
  • Date: 2019
  • Subjects: Anaerobic digestion , Biogas , Bangladesh
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/405057 , uj:33996 , Citation: Rahman, K.M., et al. 2019 : Determination of the potential impact of domestic Anaerobic Digester Systems: a community based research initiative in rural Bangladesh.
  • Description: Abstract : This research examines the potential impact of domestic anaerobic digester (AD) systems adopted in Bangladesh and similar developing countries. Cattle dung and poultry litter feed stocks were specifically investigated, because these were freely available and plentiful to people living within agricultural areas of rural Bangladesh. Data was collected to ascertain whether these two representative AD facility types provide tangible social, economic and environmental impact that benefits homeowners. Primary quantitative and qualitative data was obtained by field data collection, and meeting with expert groups and stakeholders. Empirical analysis conducted revealed that variations were found in the biomass feedstocks available on different sites but also differences were apparent in terms of the operations and maintenance (O and M) systems of the biogas plants operated. The biogas and methane yield variation was also measured, and variations were found in the cattle dung and poultry litter AD yield capacity. Overall, 64% of feedstock was utilised, 91% of biogas plants remain underfed and energy yield efficiency was 57% from cattle smallholdings’ AD and 28% from poultry farms’ AD. These results showed that small scale AD can offer a significant impact upon rural lifestyles through augmented economics, improved social activities, relationship building with neighbours and improved lifestyle achieved via time savings accrued. These results could help rural entrepreneurs, AD equipment providers and government institutions to develop a road map to implement future AD installation on a much wider geographical scale.
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