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A review of municipal solid waste data for Harare, Zimbabwe

- Nhubu, T., Muzenda, E., Mbohwa, Charles, Patel, B.

  • Authors: Nhubu, T. , Muzenda, E. , Mbohwa, Charles , Patel, B.
  • Date: 2019
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/400914 , uj:33482 , Citation: Nhubu, T. et al. 2019. A review of municipal solid waste data for Harare, Zimbabwe.
  • Description: Abstract: Municipal solid waste (MSW) data sources in Harare metropolitan province show significantly varying data with regards to generation and composition. The sources of variations include data lumping; exclusion of MSW managed outside the formal system and remain uncol-lected, lack of a clear definition of what constitutes MSW within the Zimbabwean context as well as temporal variations. It is therefore important for waste generation and characterisation studies to be undertaken building upon the already existing datasets to ensure the accuracy and reliability needed for data credibility for use in MSW management planning.
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A review of waste tyre pyrolysis : a discussion and analysis

- Nkosi, N., Muzenda, E., Belaid, M.

  • Authors: Nkosi, N. , Muzenda, E. , Belaid, M.
  • Date: 2019
  • Subjects: Reactor Selection , Types of Pyrolysis Products , Tyre derived Products,
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/403903 , uj:33864 , Citation: Nkosi, N., Muzenda, E. & Belaid, M. 2019. A review of waste tyre pyrolysis : a discussion and analysis.
  • Description: Abstract: Over the years, the prospective of end-of-life tyres as a source of fuel, a chemical feedstock and carbonaceous material through pyrolysis has been explored immensely. Through literature review evaluation and analysis, this paper aims to present and discuss the development of waste tyre pyrolysis process as well as the derived products with their possible application pathways. The various reactors that can be employed during the pyrolysis process are discussed. Furthermore, the different types of pyrolysis processes as well as their influence on product yield are highlighted. The paper drew the conclusion that the pyrolysis literature which has been continuously developed over the years emphasize the need to fully understand how operating conditions such as temperature, pressure, heating rate, retention time, feed size; material feed rate ; reactor selection and the type of pyrolysis influence the selection and optimization of product stream/s.
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A review on factors affecting municipal solid waste generation

- Masebinu, S. O., Akinlabi, Esther Titilayo, Muzenda, E., Aboyade, A. O., Mbohwa, Charles, Manyuchi, M., Naidoo, P.

An investigation into the effect of temperature on the leaching of copper-matte

- Muzenda, E., Ramatsa, I.M., Ntuli, F., Belaid, M., Tshwabi, P.M

Anaerobic treatment of opaque beer wastewater with enhanced biogas recovery through Acti-zyme bio augmentation

- Manyuchi, M. M., Mbohwa, Charles, Muzenda, E.

Bio ethanol from sewage sludge: A bio fuel alternative

- Manyuchi, M. M., Chiutsi, P., Mbohwa, Charles, Muzenda, E., Mutusva, T.

  • Authors: Manyuchi, M. M. , Chiutsi, P. , Mbohwa, Charles , Muzenda, E. , Mutusva, T.
  • Date: 2018
  • Subjects: Bio ethanol , Biomass , Hydrolysis
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/267396 , uj:28365 , Citation: Manyuchi, M.M. 2018. Bio ethanol from sewage sludge: A bio fuel alternative. South African Journal of Chemical Engineering, 25:123-127. https://doi.org/10.1016/j.sajce.2018.04.003. , ISSN: 1026-9185
  • Description: Abstract: In this study, the potential to fully exploit sewage sludge as a raw material for bio ethanol a source of bio fuel is investigated. Sewage sludge hydrolysate was first made by introducing Bacillus flexus in order for saccharification to take place before fermenting to bio ethanol using yeast. The hydrolysate was then prepared for fermentation by introducing 10 g/L of peptone, 2 g/L of KH2PO4 and 1 g/L of MgSO4. Af- terwards, fermentation was allowed to take place at varying pH (4.0e7.0), temperature (15e45 o C), in- cubation time (10e70 h) and yeast concentrations (2e10% (v/v). Bio ethanol concentrations were characterized through spectrophotometry and its physicochemical properties analyzed by standard methods. Pearson Correlations Coefficients in MATLAB 13.0 were used to determine the coefficients of interaction between the various parameters in bio ethanol production at 95% confidence interval. Highest bio ethanol yields of greater than 40 mL/L were achieved at an incubation period of 10 days, with an operating temperature of 30 o C and pH of 6.5 with yeast concentration of 6% wt. The interactions between incubation temperature and pH had the best interaction coefficient of 0.9759 being achieved for optimal bio ethanol yield. The bio ethanol produced had a flash point of 19.2 o C, pour point of 4.9 o C, cloud point of 20 o C and viscosity of 1.30 cP.
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Biogas use as fuel in spark ignition engines

- Kukoyi, T.O., Muzenda, E., Akinlabi, Esther Titilayo, Mashamba, A., Mbohwa, Charles, Mahlatsi, T.

Biological treatment of distillery wastewater by application of the vermifiltration technology

- Manyuchi, M. M., Mbohwa, Charles, Muzenda, E.

Biological treatment of distillery wastewater by application of the vermifiltration technology

- Manyuchi, M. M., Mbohwa, Charles, Muzenda, E.

  • Authors: Manyuchi, M. M. , Mbohwa, Charles , Muzenda, E.
  • Date: 2017
  • Subjects: Distillery effluent , Eisenia Fetida , BOD
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/259500 , uj:27305 , Citation: Manyuchi, M.M., Mbohwa, C. & Muzenda, E. 2017. Biological treatment of distillery wastewater by application of the vermifiltration technology.
  • Description: Abstract: In this study distillery wastewater was treated using the vermifiltration technology in a bid to reduce downstream contamination by the effluent. 10kg of Eisenia Fetida earthworms were used as the vermifiltration media in a 0.5m x 0.5m x 0.3m vermifiltration bed over a 40 hour period cycle. The distillery effluent physicochemical parameters which included pH, total Kjeldahl nitrogen (TKN), biological oxygen demand (BOD), total dissolved solids (TDS), total suspended solids (TSS) and the chemical oxygen demand (COD) were measured every 5 days. The vermicompost which was produced as a result of the vermifiltration process’s nitrogen, phosphorous and potassium composition was also determined. The distillery effluent pH changed from acidic to neutral whilst a decrease of 94.9% was observed for the TKN, 91.1% for the BOD, 91.9% for the TDS, 92.4% for the TSS and 89.4% for the COD upon treatment with vermifiltration. The vermicompost, a by-product of the vermifiltration process had a nitrogen, phosphorous and potassium composition of 1.87%, 0.87% and 0.66% respectively.
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Char production through the co-pyrolysis of coal and biomass in a fixed FED reactor

- Motlhatlhedi, T. J., Muzenda, E., Mamvura, T. A.

  • Authors: Motlhatlhedi, T. J. , Muzenda, E. , Mamvura, T. A.
  • Date: 2020
  • Subjects: Cow dung , Char , Coal
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/461807 , uj:41146 , Citation: Motlhatlhedi, T.J., Muzenda, E. & Mamvura, T.A. 2020. Char production through the co-pyrolysis of coal and biomass in a fixed FED reactor.
  • Description: Abstract: Coal contributes to 40% of the world’s energy production and the process of energy production from coal contributes to 40% of the world’s carbon dioxide emissions which have led to global warming and climate change. Thermochemical processes like pyrolysis, gasification and carbonification are used to utilize coal and this coal can be mixed with other sources of energy such as biomass for environmental protection, a higher energy densification and char yield. In this study Morupule coal was co-pyrolyzed with cow dung in a fixed bed reactor with the aim of producing char whilst reducing the net carbon dioxide emissions. Co-pyrolysis of coal with biomass yields char, gas and liquid fuel. Char is used in various sectors such as agriculture to improve soil quality hence increasing crop yields and as an adsorbent for wastewater treatment. The co-pyrolysis process was performed at 500oC and atmospheric pressure under an inert atmosphere which contained argon. Pyrolysis using a fixed bed reactor was performed on coal and cow dung at blend ratios of coal to cow dung of 0:100, 50:50, 60:40, 70:30, 80:20, 90:10, and 100:0. Proximate analysis results indicated that char had a higher fixed carbon compared to those from the individual substrates. Calorific value (CV) tests of the chars indicated that reducing to 90:10 ratio the cow dung concentration resulted in CV increases. This study shows that there is a synergic effect between the sub-bituminous Morupule coal and cow dung.
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Chemical absorption of carbon dioxide in biogas purification

- Maile, O. I., Muzenda, E., Tesfagiorgis, H.

Comparative evaluation of the performance of a bi-fuel vehicle on biogas and natural gas

- Kukoyi, T. O., Muzenda, E., Mbohwa, Charles

Diffusion in saturated clayey barrier medium

- Agbenyeku, E. E., Muzenda, E., Msibi, M. I.

  • Authors: Agbenyeku, E. E. , Muzenda, E. , Msibi, M. I.
  • Date: 2017
  • Subjects: Leachate , Percolation , Earthen barrier
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/223036 , uj:22415 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, M.I. 2017. Diffusion in saturated clayey barrier medium. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
  • Description: Abstract: The design of clay/clayey barriers for the containment of buried wastes conventionally has been based on the assumption that the hydraulic conductivity controls the rate of leachate percolation. However, recent studies show that diffusion is a controlling mechanism of solute transport in many fine-grained soils. Although the measurement of the hydraulic conductivity of finegrained soils is comparatively a common practice in soil engineering, the measurement of diffusion coefficients is not. As such, it is becoming increasingly essential to assess the movement of chemicals through soil barriers due to diffusion. Studies indicate that diffusion may be an important, if not dominant mechanism of contaminant transport through waste containment barriers. This paper is therefore in line with the efforts made in the measurement of diffusion coefficients of inorganic chemicals passing through saturated soils. Herein, both steady-state and transient equations relating to the diffusive transport of inorganic chemicals are presented. A number of factors affecting diffusion coefficients are identified and a simple method for measuring diffusion coefficients for a compacted barrier is defined. The definition for the diffusion coefficient of soil called the effective diffusion coefficient, D* is seen to vary widely. Generally, the variations are due to the different factors affecting diffusion of solutes in soil and the various ways of including the volumetric water content in the governing equations. Hence, errors in interpretation and comparison of D* values can occur if the appropriate definition is not used. In a nutshell, the concept of diffusion may be unfamiliar to many soil specialists, worsened by the myriad terminologies linked to the study of diffusion in soils. Thus the study attempts to acquaint soil engineers with vital information for the measurement of diffusion coefficients for barrier designs.
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Economic analysis of biogas upgrading and utilization as vehicular fuel in South Africa

- Masebinu, S. O., Aboyade, A. O., Muzenda, E.

  • Authors: Masebinu, S. O. , Aboyade, A. O. , Muzenda, E.
  • Date: 2015
  • Subjects: Biomethane , Economics , Gas processing cost
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/72861 , uj:18338 , Citation: Masebinu, S.O., Aboyade, A.O. & Muzenda, E. 2015. Economic analysis of biogas upgrading and utilization as vehicular fuel in South Africa.
  • Description: Abstract: Economic and sensitivity analysis of a simulated biogas upgrading plant using a gas permeation software has been presented in this study. The effect of three process conditions on gas processing cost (GPC) were simulated. An increase in CO2 increased the GPC from $0.73 to $1.39/m3 of biomethane while an increase in feed pressure increased GPC from $0.65 to $1.16/m3 of biomethane. As the feed flow rate increased from 80-140 m3/h, the product flow rate increased from 46-100 m3/h while the GPC decreases from $0.79 to $0.39/m3 of biomethane. At optimized condition, the calculated GPC was $0.46/m3 of biomethane. The NPV, IRR and BCR for producing biomethane was R15,240,343, 22.41% and 2.05 respectively with a break-even in the 5th year. Using CBG over gasoline, the end user saves 34% of annual fuel cost which is approximately R47,255 with a payback period of one year and three months for vehicle retrofitting. The fuel prices differential between gasoline and CBG as well as the overall savings, makes CBG attractive to the producer and end user.
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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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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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Effect of blending coal with torrefied biomass for possible application in energy production

- Mamvura, T., Muzenda, E.

  • Authors: Mamvura, T. , Muzenda, E.
  • Date: 2016
  • Subjects: Coal , Biomass , Blending , Torrefaction
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/93696 , uj:20382 , Citation: Mamvura, T. & Muzenda, E. 2016. Effect of blending coal with torrefied biomass for possible application in energy production.
  • Description: Abstract: Emissions of greenhouse gases mostly from fossil fuels are responsible for global warming and climatic changes. This has led to research in bioenergy to reduce greenhouse emissions because bioenergy is part of the carbon cycle, and can only emit greenhouse gases that are part of the carbon cycle. The drawback is its low calorific value when it is in its raw form. Torrefaction improves its energy content to values that are comparable to coal. In this study, marula seeds and blue gum wood, two of South Africa most abundant biomass, were blended with coal both raw and torrefied to see the impact of the torrefaction process on energy density. Blending was done at different ratios to see the optimum results. Results showed that highest calorific value was obtained at 100% marula seeds and 0 % coal, and it was recommended for further studies. Blue gum wood due to its high moisture had slightly higher heating value than the reference coal but from an economical point of view it was not attractive for further studies. This showed the significance of the torrefaction process in increasing heating value of selected biomass in the hope of reducing effects of greenhouse gas emissions.
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Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites

- Reddy, K. Obi, Maheswari, C. Uma, Reddy, K. Ramakrishna, Shukla, M., Muzenda, E., Rajulu, A. Varada

  • Authors: Reddy, K. Obi , Maheswari, C. Uma , Reddy, K. Ramakrishna , Shukla, M. , Muzenda, E. , Rajulu, A. Varada
  • Date: 2015
  • Subjects: Borassus fruit fiber , Chemical treatments , Spectroscopy
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/73565 , uj:18426 , Citation: Reddy, K.O. et al. 2015. Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites.
  • Description: Abstract: The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber reinforced epoxy composites. Composites were prepared by hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH), and alkali combined with silane (3- aminopropyltriethoxysilane) treatments on the fibers surface were carried out. Examinations through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made by chemically modified and untreated Borassus fibers were studied using a Universal Testing Machine (UTM). Based on the experimental results, it was found that the tensile properties of the Borassus reinforced epoxy composites were significantly improved, as compared with the neat epoxy. It was also found that the fiber treated with combination of alkali and silane exhibited superior mechanical properties as compared with alkali and untreated fiber composites. The nature of fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites.
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Electrolytic deposition of manganese dioxide from Nigerian manganese ore using graphite electrodes

- Muriana, R. A., Omeye, L. U., Abubakre, O. K., Muzenda, E., Ndlovu, S., Abdulkareem, A. S.

  • Authors: Muriana, R. A. , Omeye, L. U. , Abubakre, O. K. , Muzenda, E. , Ndlovu, S. , Abdulkareem, A. S.
  • Date: 2017
  • Subjects: Driving potential , Electrolytic deposition , Electrolytic manganese dioxide
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/250364 , uj:26088 , Citation: Muriana, R.A. et al. 2017. Electrolytic deposition of manganese dioxide from Nigerian manganese ore using graphite electrodes. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
  • Description: Abstract: Super rich manganese dioxide got deposited at the anode when manganese sulphate solution was electrolytically decomposed, and the deposits called Electrolytic Manganese Dioxide (EMD). Manganese ore containing about 35.79% manganese from Ka’oje (Kebbi State, Nigeria) with pyrolusite (MnO2) as the major manganese mineral alongside iron mineral present as hematite, was the resource material. Some 1973.31g of beneficiated ore sample (75 to 600μm) was isothermally reduced with charcoal (52.17% carbon) at 6000C for one hour. The paramagnetic high oxide ore got reduced to a ferromagnetic lower oxide containing 38.90% manganese. Some 610g portions of the reduced ore were leached in varied concentrations of sulphuric acid (1.0M, 1.5M and 2.0M) at 500C for one hour and 42.36% leaching efficiency was achieved with 2.0M acid. Calculated elemental mass balance revealed that 2.0M acid dissolved 100.52g of manganese into the leach liquor as manganese sulphate along with 13.83g of iron and 7.47g of aluminium as the major elements. Each leach filtrate was purified with aqueous sodium hydroxide except some 600ml of filtrate from 2.0M acid leaching which was decomposed unpurified for comparison. The filtrates were respectively electrolyzed at 2.5V, 3.0V and 4.0V driving potentials for five hours using graphite electrodes. Analyses showed that the purified liquor extracted with 2.0M acid and electrolysed at 4.0V deposited the best quantity and quality of EMD, containing 98% MnO2. This high grade EMD is a principal precursor in Ferro-alloy production for steel making and also an important raw material for electrochemical cells and other allied manganese-based chemicals.
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Energy potential of food waste generated by a middle class neigbourhood in Nigeria through anaerobic digestion

- Kukoyi, T. O., Muzenda, E., Mbohwa, Charles

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