Zeolitic mineral liner as hydraulic and buffering material
- Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Innocent Mandla
- Date: 2014
- Subjects: Leachate , Zeolites - Linings , Solid waste management , Hydraulics , Zeolites - Analysis
- Type: Article
- Identifier: uj:5093 , http://hdl.handle.net/10210/13683
- Description: Laboratory tests were done using a bespoke device to investigate landfill leachate seepage through a circular failed geocomposite liner. Pressures simulating actual landfill waste loads were applied to the lining system. The buffering capacity of a natural zeolitic mineral layer was investigated by measuring the leachate seepage rate and anionic (Cl and HCO3) contaminant transport through the geo-composite liner-buffering strata (BS). Simulated landfill waste loads from 25-150kPa were introduced to the system at intervals. The findings showed considerable reduction in seepage rate over the increased pressure. The seepage reduction is ascribed to the reduced liner transmissivity, θ and compressed soil layer. The natural zeolitic soil exhibited poor buffering of Cl ions but showed a fair outcome in the case of HCO3 ions. Data for seepage rates were compared with predicted values from existing equations by Forchheimer and Giroud. The comparisons showed inapplicability to this study and to real life scenarios, if conditions of perfect contact at the polyethylene/soil interface were assumed. Nonetheless, Giroud’s equation for good contact condition gave considerable seepage rate prediction through a failed geo-composite liner.
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Weight loss and microstructural studies of stressed mild steel in apple juice
- Authors: Afolabi, A. S. , Muhirwa, A. C. , Abdulkareem, A. S , Muzenda, Edison
- Date: 2014
- Subjects: Apple juice , Weight loss
- Type: Article
- Identifier: uj:4814 , ISSN 1452-3981 , http://hdl.handle.net/10210/12255
- Description: This study investigated the effect of internal stress of mild steel on its corrosion behaviour in apple juice by weight loss and microstructural analyses....read full paper
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Waste to energy opportunities in Botswana : a case study review
- Authors: Charis, Gratitude , Danha, Gwiranai , Muzenda, Edison , Patel, Bilal
- Date: 2019
- Subjects: Case study , Conversion , Energy
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/404776 , uj:33961 , Citation: Charis, G. et al. 2019. Waste to energy opportunities in Botswana : a case study review.
- Description: Abstract: The need for efficient solid waste management practices has become more pressing, especially in developing nations largely experiencing a population boom in urban areas. Currently, however, it is only developed nations that have embraced resource efficient practices and technologies to produce energy, heat, fuels and compost from solid waste. This paper reviews such global trends and best practices as a benchmark against current practices within the context of Botswana. It also reviews the opportunities for Waste to Energy (WtE) in this developing nation by taking a solid waste inventory. A literature survey revealed that Botswana is still operating in the previous policy direction of keeping the society clean to avoid the hygienic effects of waste. The collection and disposal of waste is partly decentralized with several private players...
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Waste management, strategies and situation in South Africa : an overview
- Authors: Muzenda, Edison , Ntuli, Freeman , Pilusa, Tsietsi Jefrey
- Date: 2012
- Subjects: Waste management - South Africa , Refuse disposal - South Africa
- Type: Article
- Identifier: uj:6044 , ISBN 2010-376X , http://hdl.handle.net/10210/10452
- Description: This paper highlights some interesting facts on South African’s waste situation and management strategies, in particular the Integrated Waste Management. South Africa supports a waste hierarchy by promoting cleaner production, waste minimisation, reuse, recycling and waste treatment with disposal and remediation as the last preferred options in waste management. The drivers for waste management techniques are identified as increased demand for waste service provision; increased demand for waste minimisation; recycling and recovery; land use, physical and environmental limitations; and socio-economic and demographic factors. The South African government recognizes the importance of scientific research as outlined on the white paper on Integrated Pollution and Waste Management (IP and WM) (DEAT, 2000).
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Waste management key participants in developing countries : a discussion
- Authors: Nkosi, Nhlanhla , Muzenda, Edison
- Date: 2013
- Subjects: Waste management - Developing countries
- Type: Article
- Identifier: uj:4838 , http://hdl.handle.net/10210/12486
- Description: This paper discusses key role players in waste management in developing countries. The identified key players are municipal governments, informal private sector, community based organizations, and non-governmental organizations. The paper concludes by addressing key issues and constraints, informal sector integration as well as challenges faced in the management of waste.
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Waste management challenges to opportunities in the west rand district municipality, Gauteng, South Africa : initiatives
- Authors: Ginindza, Bongekile , Muzenda, Edison
- Date: 2016
- Subjects: Green house gases , Illegal dumping , Informal recycling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/215501 , uj:21424 , Citation: Ginindza, B & Muzenda, E. 2016. Waste management challenges to opportunities in the west rand district municipality, Gauteng, South Africa : initiatives.
- Description: Abstract: The increased waste management and minimisation developments have placed enormous pressure on the West Rand District Municipality (WRDM) considering the rapidly shrinking airspace of the 5 landfill sites, rapid economic and population growth, lack of proper separation facility, which have led to waste management challenges in 4 Local Municipalities (LMs) of the WRDM i.e., Randfontein, Mogale City, Merafong City and Westonaria. Other waste management challenges faced by WRDM include recycling that is mostly done by unregistered informal recyclers/scavengers, shortage of waste transportation services, illegal dumping, in appropriate final waste disposal, generation of greenhouse gases at landfill sites such as methane gases that contributes to air pollution/global warming and water pollution through leachate migration. However, these challenges can be turned into useful resources and opportunities if properly managed and can provide employment for WRDM personnel including the conversion of waste into energy through thermal combustion and bio-gasification.
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Volatile organic compounds- biodiesel thermodynamic interactions: influence of temperature
- Authors: Ramdharee, Sashay , Muzenda, Edison , Belaid, Mohamed
- Date: 2016
- Subjects: Activity coefficients , Biodiesel , Phase equilibrium , Universal functional activity coefficient
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93659 , uj:20376 , Citation: Ramdharee, S., Muzenda, E. & Belaid, M. 2016. Volatile organic compounds- biodiesel thermodynamic interactions: influence of temperature.
- Description: Abstract: This work investigated the suitability of biodiesel (predominantly Methyl Linolenate, Methyl Palmitate, Methyl Oleate and Methyl Stearate) as an absorbent for the recovery of VOCs from waste gas process streams through absorption. The objective was to predict the vapour liquid equilibria (VLE) data in the form of infinite dilution activity coefficients for five VOC families, in fatty acid methyl ester solvents at varying temperature. The Original Universal Functional Group Activity Coefficient (UNIFAC) model (Fredenslund et al., 1975) [1], Modified UNIFAC (Larsen et al., 1981) [2] and Modified UNIFAC (Bastos et al., 1988) [3] was used to predict the required phase equilibrium. Alkanes, alcohols and acids/ester interactions showed an increase in activity coefficients with increase in temperature. The influence of temperature on the activity coefficients for alkene and amine families was negligible. The solubility of VOCs in biodiesel decreases with increase in ester hydrocarbon unsaturation. The solubility of VOCs increased with increase in ester molecular weight.
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Volatile organic compounds – polymeric solvents interactions – a thermodynamic computational attempt
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Phase equilibrium , Solubility , Volatile organic compounds , Normal methyl pyrrolidone
- Type: Article
- Identifier: uj:4770 , ISSN 2320–4087 , http://hdl.handle.net/10210/11945
- Description: This work attempted to model the phase equilibrium involving 50 volatile organic compounds (VOCs) with furfural and normal methyl pyrrolidone (NMP). Polar furfural and dipolar aprotic NMP were tested in this work as potential solvents for the abatement of selected VOCs through physical absorption. Five (5) VOC family groups were studied namely alkanes, alkenes, alcohols, aldehydes and carboxylic groups. The modified UNIFAC Dortmund and Lyngby were used in the phase equilibrium computation. NMP showed better absorption affinity for alkenes, alcohols and carboxylic acids compared to furfural. The solubility decreased with increase in size of the VOCs for both solvents.
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Volatile organic compounds – biphenyl thermodynamic interactions
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Absorption , Activity coefficient , Phase equilibrium , Volatile organic compounds , Thermodynamics
- Type: Article
- Identifier: uj:4989 , ISSN 2078-0966 , http://hdl.handle.net/10210/13124
- Description: This work focused on the thermodynamic interactions involving volatile organic compounds (VOCs) and biphenyl. The solubility of 60 VOCs in biphenyl was studied using group contribution methods. The modified UNIFAC Dortmund and Lyngby were used to compute the required phase equilibrium in the form of infinite dilution activity coefficients. Six family groups were studied mainly alkanes, alkenes, alkynes, aldehydes, alcohols, and carboxylic acids. The Modified UNIFAC Dortmund performed better than the Modified UNIFAC Lyngby. Biphenyl showed excellent absorption affinity for all VOCs in particular for alkynes and aldehydes. The solubility decreased with increase in VOC molecular weight.
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Volatile organic compounds abatement : a critical discussion of destruction techniques
- Authors: Muzenda, Edison , Belaid, Mohamed
- Date: 2013
- Subjects: Volatile organic compounds , Bioreactors
- Type: Article
- Identifier: uj:4968 , http://hdl.handle.net/10210/13069
- Description: This paper critically discusses volatile organic compounds destruction techniques. The methods discussed are thermal and recuperative oxidation, catalytic oxidation, regenerative oxidation, flares and bioreactors. Examples of bioreactors discussed are bio-filters, bio-trickling filters and bio-scrubbing filters. The principle of operation as well as the strength and weaknesses of each methods are given.
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Vermicomposting of soybean and maize straw residues as an agro waste management initiative
- Authors: Manyuchi, Musaida Mercy , Mbohwa, Charles , Muzenda, Edison
- Date: 2017
- Subjects: Bio fertiliser , Earthworms , Nitrogen
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/260136 , uj:27384 , Citation: Manyuchi, M.M, Mbohwa, C. & Muzenda, E. 2017. Vermicomposting of soybean and maize straw residues as an agro waste management initiative.
- Description: Abstract: In this study, maize waste and soy bean residue were vermicomposted as a way of harnessing bio products from agro waste in a bid to promote sustainability and proper waste management to bio fertilizers. Maize and soy bean residues were vermicomposted in a 9m by 1m vermicomposting bed over a period of 30 days using Eisenia Fetida earthworms at standard conditions. The physicochemical parameters of the organic waste including the organic loading (OC), nitrogen, phosphorous and potassium (NPK) content as well as trace elements such as calcium (Ca), magnesium (Mg) and sodium (Na) were determined using standard methods. The behavior of the earthworms in terms of mass and length was also quantified. Upon increase in the vermicomposting period, the OC increased by 38%, NPK composition by 50%, 50% and 35% respectively. The Ca, Mg and Na composition by 10%, 23% and 30% respectively. The earthworms mass and length increased by 60% and 20% respectively. From the results obtained, vermicomposting offers a sustainable opportunity for crop waste management to bio fertilizers.
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Using tyre derived fuel : an analysis of the benefits
- Authors: Nkosi, Nhlanhla , Muzenda, Edison , Zvimba, John
- Date: 2013
- Subjects: Waste tyres , Waste tyre derived fuel
- Type: Article
- Identifier: uj:4939 , http://hdl.handle.net/10210/13039
- Description: This paper discusses the socio-economic and environmental benefits of using waste tyre derived fuel. The paper outlines the uses of waste tyres as an alternative source of energy and various applications that have been implemented internationally, and use these as bench marks for possible solutions in the South African waste tyre problem, as the country gradually adapts to the waste to energy initiatives through governmental, communities and private sector efforts. The method used to compile this paper includes using a triangulation method, which involves literature analysis, site visits and telephonic interviews
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Treatment of acid mine drainage using un-activated bentonite and limestone
- Authors: Nkonyane, Thembelihle , Ntuli, Freeman , Muzenda, Edison
- Date: 2012
- Subjects: Acid mine drainage , Bentonite , Limestone , Heavy metal removal
- Type: Article
- Identifier: uj:6045 , ISSN 2010-3778 , http://hdl.handle.net/10210/10453
- Description: Please refer to full text to view abstract
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Transformation and utilization of agricultural waste as component of green concrete for rural housing and development schemes
- Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Mandla Innocent
- Date: 2016
- Subjects: Rice husk ash , Pozzolana , Strength of materials , Agricultural wastes - Recycling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217530 , uj:21651 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, M.I. 2016. Transformation and utilization of agricultural waste as component of green concrete for rural housing and development schemes.
- Description: Abstract: Several researchers have outlined cost saving and cement blending merits without compromising standards. As such, utilizing artificial pozzolana as supplementary cementitious materials (SCMs) in concrete engineering is well known. However, there is continual search for substitute materials. The use of Rice Husk Ash (RHA) as cementitious constituent in green concrete was studied. Its abundance paved way for the study to look into the compressive strength of the concrete type formed by partly substituting Ordinary Portland Cement (OPC) with RHA under short curing series. Analysis on RHA revealed significant properties of pozzolanic hardening. 60 cubes of 100 mm dimensions were cast with cement replacement by RHA ranging from 0-40% while adopting a 28 day targeted strength of 25 MPa as control. The cubes were cured at relative humidity (RH) of 95-100% and temperature (T) of 22-250C in a chamber for periods of 7, 14, 21 and 28 days. The outcomes displayed trends of strength gain, reduced density and compressive strength with increase in RHA. The 28 days density and strength of the normal concrete was 2465 kg/m3 and 28.57 MPa while the 10% RHA sample (i.e. best substitute matrix) had 2398 kg/m3 and 25.97 MPa respectively. The strength of 10% RHA/OPC concrete (25.97 MPa) was slightly higher than the adopted strength (25 MPa) at 28 days. This signifies its suitability as concrete constituents and can be a major cost reduction factor in rural shelter projects where less structural complexities are required. Hence, it can be employed in the construction of simple foundations and concrete composites.
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Thermodynamics of Cu (II) adsorption onto South African clinoptilolite from synthetic solution by ion exchange process.
- Authors: Kabuba, John , Ntuli, Freeman , Muzenda, Edison , Mollagee, Mansoor
- Date: 2011
- Subjects: Clinoptilolite , Adsorption , Thermodynamics , Langmuir isotherm
- Type: Article
- Identifier: uj:6250 , ISSN 2010-4618 , http://hdl.handle.net/10210/8194
- Description: The adsorption of Cu (II) ions from aqueous solution onto clinoptilolite from synthetic solutions by ion exchange was investigated. The effects of solution pH and temperature were examined. The Langmuir isotherm model was employed to calculate the different thermodynamics parameters. Thermodynamics studies revealed that the adsorption behavior of Cu (II) ions onto clinoptilolite was a spontaneous and endothermic process, resulting in higher adsorption capacities at higher temperatures.
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The waste tyre problem in South Africa : an analysis of the REDISA plan
- Authors: Nkosi, Nhlanhla , Muzenda, Edison , Zvimba, John , Pilusa, Jefrey
- Date: 2013
- Subjects: Recycling and Economic Initiative of South Africa , Waste tyre management - South Africa , Waste management - South Africa , Waste tyre utilization - South Africa
- Type: Article
- Identifier: uj:4837 , http://hdl.handle.net/10210/12485
- Description: This paper reviews the proposed REDISA Plan which is meant to address the waste tyre problem. The study objectives were achieved through reviewing the REDISA gazetted Plan and interviewing REDISA personnel. The Plan does not address waste tyre problem only but has the potential to contribute to job creation, capacity building, establishment of small businesses as well as research and development of new and innovative waste tyre utilization techniques. The Plan is seen as the only viable approach to remedy the waste tyre problem through the introduction of a proposed levy fee of R2.30, and all tyre producers and dealers are expected to subscribe to the plan. Despite it being gazetted, the plan is still awaiting implementation.
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The Sustainability of Biodiesel Synthesis from Different Feedstocks: A Review
- Authors: Bombo, Katlego , Lekgoba, Tumeletso , Azeez, Oluwatosin , Muzenda, Edison
- Date: 2021
- Subjects: Biofuel , Jatropha curcas , Microalgae
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/10210/494208 , uj:44788 , Citation: Bombo, K., Lekgoba, T., Azeez, O. and Muzenda, E., 2021. The sustainability of biodiesel synthesis from different feedstocks: a review. , ISSN: 1337-7027
- Description: Abstract: Currently, the world is facing an energy crisis due to an increase in the global energy demand and this has led to an increased dependence on fossil fuels for energy generation and transportation. The steady rise in the world population which is more than seven billion currently is met with an increase in fossil fuel consumption thereby increasing the threat of fossil depletion and an apparent energy deficit. Fossil fuel emissions pose a threat to the environment and the general human population due to risks posed by greenhouse gases they produce. Biodiesel is recognized as a suitable alternative to fossil fuels due to its biodegradable, renewable and environmentally friendly nature. Biodiesel sources are classified into first, second and third generation based on their origin and type of feedstocks used. There are fourth-generation feedstocks which are biologically man-made resources that are currently at the embryotic stage of research. This paper reviews the sustainability of using Jatropha curcas seeds and microalgae for the production of biodiesel. It highlights an evaluation of the oil yield, composition and performance of the biodiesel derived from both sources whilst assessing the viability of individual feedstocks in biodiesel production. Additionally, different methods of biodiesel production are also assessed.
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The sequestration of heavy metals contaminating the Wonderfonteinspruit catchment area using natural zeolite
- Authors: Diale, Palesa. P. , Mkhize, S.S.L. , Muzenda, Edison , Zimba, Josephat
- Date: 2011
- Subjects: Wonderfonteinspruit Catchment Area (South Africa) , Natural zeolite , Water pollution , Heavy metals
- Type: Article
- Identifier: uj:6086 , http://hdl.handle.net/10210/10938
- Description: For more than 120 years, gold mining formed the backbone the South Africa’s economy. The consequence of mine closure was observed in large-scale land degradation and widespread pollution of surface water and groundwater. This paper investigates the feasibility of using natural zeolite in removing heavy metals contaminating the Wonderfonteinspruit Catchment Area (WCA), a water stream with high levels of heavy metals and radionuclide pollution. Batch experiments were conducted to study the adsorption behavior of natural zeolite with respect to Fe2+, Mn2+, Ni2+, and Zn2+. The data was analysed using the Langmuir and Freudlich isotherms. Langmuir was found to correlate the adsorption of Fe2+, Mn2+, Ni2+, and Zn2+ better, with the adsorption capacity of 11.9 mg/g, 1.2 mg/g, 1.3 mg/g, and 14.7 mg/g, respectively. Two kinetic models namely, pseudo-first order and pseudo second order were also tested to fit the data. Pseudo-second order equation was found to be the best fit for the adsorption of heavy metals by natural zeolite. Zeolite functionalization with humic acid increased its uptake ability.
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The effect of zinc ion concentration and pH on the leaching kinetics of calcined zinc oxide ore
- Authors: Muzenda, Edison , Simate, Geoffrey S.
- Date: 2011
- Subjects: Dissolution kinetics , Leaching , Zinc ions , Zinc oxide
- Type: Article
- Identifier: uj:4701 , http://hdl.handle.net/10210/10940
- Description: Previous studies on the dissolution of zinc oxide have concentrated on the effects of temperature, reagent concentration, particle size and agitation rate, among other factors. However, there is dearth data on the effect of a combination of product concentration and pH on leaching rates. This work examines the effects of the concentration of pH and zinc ions on the dissolution kinetics of zinc oxide. The results showed that the rate of zinc dissolution was greatest at lower pHs. This is because at lower pH, the concentration of acid (H+ ions) is also expected to be high (pH = log10[H+]), thus increasing the reaction kinetics in accordance with the kinetic molecular theory. The rate of reaction was found to increase with an increase in the concentration of zinc ions (Zn2+), which is in contrast to established theories. This observation can be explained by the fact that since heat energy produced (via an exothermic reaction) was continuously being dissipated through a constant temperature water bath it favoured zinc oxide dissolution. Zinc oxide ore at 62.5% purity also comprised of other metal oxides (e.g., iron, copper, manganese, etc) which were simultaneously leached. Since the solution was recycled, the concentration of iron, for example, could have also increased. Since zinc is more reactive than iron, two reaction mechanisms could have possibly been occurring at the same time, i.e., the dissolution of zinc oxide ore by sulfuric acid and the displacement of iron in solution by zinc in zinc oxide forming iron hydroxide.
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The effect of poly(ethylene-alt-maleic anhydride) on the reduction crystallization behaviour of nickel powder
- Authors: Bodoza, T.F. , Ntuli, Freeman , Chauke, D.F. , Muzenda, Edison
- Date: 2013
- Subjects: Poly(ethylene-alt-maleic anhydride) , Nickel powder precipitation , Particle size distribution
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/382392 , uj:4768 , ISSN 1939-019X , http://hdl.handle.net/10210/11943
- Description: The effect of poly(ethylene-alt-maleic anhydride) (EMA), an additive used in nickel powder precipitation, has been studied using sodium hypophosphite as a reducing agent. Reduction experiments were conducted using a 10 L stainless steel batch reactor. The effect of EMA was investigated by studying the evolution of the particle size distribution (PSD) and its derived moments, specific surface area, rate of reduction, pH–redox potential and elemental composition of the powder product. EMA has been found to act as a reduction catalyst and anti-agglomerating agent. The major particulate processes identified were size dependent aggregation, molecular growth and breakage.
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