Browsing by Author "Seay, Jeffrey"

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    Characterization of Banana Peels Wastes as Potential Slow Pyrolysis Feedstock
    (Journal of Sustainable Development, 2018) Kabenge, Isa; Omulo, Godfrey; Banadda, Noble; Seay, Jeffrey; Zziwa, Ahamada; Kiggundu, Nicholas
    Uganda is the world’s second largest producer and consumer of banana after India. This has resulted into vast quantities of banana wastes, including the leaves, pseudostem, stalks, rejected and rotten fruits and the fruit peels. This study focuses on the characterization of banana peels to yield banana peels vinegar (BPV), tar and biochar as value added products that can be useful to farmers. Dried banana peels were characterized via proximate, ultimate, lignocellulosic, thermogravimetric (TG), and calorific value analyses. The obtained results showed that the volatile matter and fixed carbon contents were 88.02% and 2.70% while carbon, nitrogen and sulphur were 35.65%, 1.94% and 20.75 ppm respectively. The hemicellulose, cellulose and lignin contents were 41.38%, 9.90% and 8.90% while the higher and lower heating values were 16.15 MJ/kg and 14.80 MJ/kg. The maximum devolatilization rate in the banana peel biomass occurred in the temperatures range of 450–550oC which was taken as the slow pyrolysis regime temperature. The high levels of fixed carbon, volatile matter and ash contents were strong indicators that banana wastes are adequate feedstock for pyrolysis work to yield bio-infrastructure products. Similarly, the lignin, cellulose and hemicellulose fractions had significant correlation between the biomass heating values and the eventual chemical compounds present BPV and biochar. The characterization properties of the banana peels are akin to the leaves and pseudostem and thus are suitable for pyrolysis process.
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    Characterization of Slow Pyrolysis Wood Vinegar and Tar from Banana Wastes Biomass as Potential Organic Pesticides
    (Journal of Sustainable development, 2017) Omulo, Godfrey; Willett, Sarah; Seay, Jeffrey; Banadda, Noble; Kabenge, Isa; Zziwa, Ahamada; Kiggundu, Nicholas
    Slow pyrolysis process has been used in the recent past to yield wood vinegar from various biomass wastes with a quest to investigate their chemical composition and possible uses. This study utilizes the abundant banana wastes in Uganda including leaves, pseudostem and peels (mpologoma, kisansa and kibuzi species) in the slow pyrolysis process to yield vinegar, tar and biochar. Characterization of these banana wastes’ vinegar and tar fractions were investigated via chromatographic and physicochemical analysis. The principle compounds present in the banana wastes vinegar and tar as per percentage peak areas were acids (68.6%), alcohols (62.5%), ketones (27.6%), phenols (25.7%) and furans (21.8%). The products characterization indicate that vinegar and tar contain compounds that can be used as pesticides, termiticide, fungicides, insect repellants, anti-leaching and soil degradation agents. Thus wood vinegar and tar can have sustainable impacts on agricultural sectors and chemical industries especially for developing countries.
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    Influence of Weather and Purity of Plasticizer on Degradation of Cassava Starch Bioplastics in Natural Environmental Conditions
    (Journal of Agricultural Chemistry and Environment, 2019) Ahimbisibwe, Michael; Banadda, Noble; Seay, Jeffrey; Nabuuma, Betty; Atwijukire, Evans; Wembabazi, Enoch; Nuwamanya, Ephraim
    The threat posed by plastics to the environment has prompted the development of bioplastics. Starch plasticized by glycerol is a key renewable resource in the production of high-quality bioplastics. Previous studies have availed information on the mechanical quality of starch-based bioplastics however there is limited information about their degradation pattern in the natural environment which this research presents. Bioplastics were buried in holes in loam sandy soil and weekly photographic data and weight were collected to reveal the effect of degradation. Weather parameters of rainfall, temperature, relative humidity, sunshine intensity and sunshine hours were recorded to establish influence of weather on degradation. A control set up in the laboratory was used to compare the results. Over time the tests revealed that as the hydrophilic enzymes break down the bioplastic, its weight initially increases (up to 87%) due to absorption of moisture and after saturation, the bioplastic is disintegrated which initiates decomposition and the bioplastic weight is steadily reduced. Degradation was further enhanced by invasion of soil organisms like worms, termites among other soil microbes. Rainfall (r = 0.857) increased the moisture in the soil which initially increased the weight of the bioplastic up to a point when the hydrophilic enzymes set into breakdown the bioplastic then the weight started to drop. This was the same case for relative humidity (r = −0.04) however; the sunlight intensity (r = 515) and hours of illumination indirectly affect the process by influencing microbial activity. An increase in the sunshine intensity increased the activity of soil organisms up to a point beyond which increased exposure caused the organisms to burrow deeper in the soil. Increase in microbial activity increased the rate of degradation of the buried bioplastics which took five to ten weeks to fully decompose (98.3%). The reduced time of degradation means that starch-based bioplastics have a high potential as sustainable substitute for petroleum-based plastics.
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    Optimizing slow pyrolysis of banana peels wastes using response surface methodology
    (Environmental Engineering Research, 2019) Omulo, Godfrey; Banadda, Noble; Kabenge, Isa; Seay, Jeffrey
    Renewable energy from biomass and biodegradable wastes can significantly supplement the global energy demand if properly harnessed. Pyrolysis is the most profound modern technique that has proved effective and efficient in the energy conversion of biomass to yield various products like bio-oil, biochar, and syngas. This study focuses on optimization of slow pyrolysis of banana peels waste to yield banana peels vinegar, tar and biochar as bio-infrastructure products. Response surface methodology using central composite design was used to determine the optimum conditions for the banana wastes using a batch reactor pyrolysis system. Three factors namely heating temperature (350-550oC), sample mass (200-800 g) and residence time (45-90 min) were varied with a total of 20 individual experiments. The optimal conditions for wood vinegar yield (48.01%) were 362.6oC, 989.9 g and 104.2 min for peels and biochar yield (30.10%) were 585.9oC, 989.9 g and 104.2 min. The slow pyrolysis showed significant energy conversion efficiencies of about 90% at p-value ≤ 0.05. These research findings are of primary importance to Uganda considering the abundant banana wastes amounting to 17.5 million tonnes generated annually, thus using them as pyrolysis feedstock can boost the country’s energy status.
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    A Perspective on a Locally Managed Decentralized Circular Economy for Waste Plastic in Developing Countries
    (Environmental Progress & Sustainable Energy, 2019) Joshi, Chandni; Seay, Jeffrey; Banadda, Noble
    Unsound post-consumer disposal is the primary pathway of plastic into the ecosystem. One way of addressing this problem is through the establishment of a circular economy for plastic. Much of the unsound disposal comes from economically disadvantaged regions where waste disposal and recycling infrastructure is limited. In economically disadvantaged regions however, the establishment of a circular economy for plastic must be locally managed and decentralized, meaning that the disposal, collection, remanufacture, and use must all occur within the same community. We suggest that waste plastic abatement strategies must be targeted to reduce, reuse, and recycle plastic waste onsite at the local level, initiating a circular economy appropriate for infrastructure limited regions. Technologies for recycling plastic must be low cost, economically viable, socially acceptable, and not adversely impact the environment, and also produce a product that has a ready local market. This is critical because unless proposed solutions are also economically viable and socially appropriate, they are unlikely to be successful, especially in underdeveloped regions. Using big data analysis, a metric for identifying countries that will have the most potential to benefit from a locally managed decentralized circular economy for plastic has been developed. The information obtained from this metric will help researchers and policy makers promote a locally managed decentralized circular economy of plastic for managing the accumulation of waste on land and its eventual migration into waterways. Additionally, we present a case study of a proposed locally managed decentralized waste plastic abatement strategy in the municipal solid waste infrastructure limited country of Uganda.
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    Reverse Engineering of Plastic Waste into Useful Fuel Products
    (Journal of Analytical and Applied Pyrolysis, 2018) Owusu, Prosper Achaw; Banadda, Noble; Zziwa, Ahamada; Seay, Jeffrey; Kiggundu, Nicholas
    This paper’s twofold aims are: to assess the potential of converting plastic waste into useful fuels in both continuous and batch pyrolysis reactors using an appropriate technology and to investigate the effect of silica-alumina catalyst on the yield and quality of pyrolytic liquid oil. The plastic waste used (HDPE, PP and PS) were obtained from Kiteezi landfill site, Kampala (Uganda). In a further step, the properties of the liquid fuel obtained from pyrolysis were also compared with commercial transportation fuel to ascertain its suitability on diesel engines.The fuel qualities were analysed using ASTM standard test methods At a degradation temperature of 450 °C, thermal pyrolysis in a batch reactor resulted in the highest yield of liquid fractions. The liquid yield of HDPE, PP and PS was found to be 80%, 82.6% and 80% by mass, respectively. In contrast, silica-alumina catalyst to feedstock ratio of 1:10 was the most effective in terms of gaseous fraction production. The gaseous fractions were: 60 wt% for the mixture, followed by HDPE (59.63 wt%), PS (59.07 wt%) and PP (49.33 wt%). A catalyst/polymer ratio of 1:10 greatly reduced the degradation temperature. The degradation temperature for HDPE, PP and PS was reduced by about 33%, 23% and 17%, respectively. The liquid oils from HDPE and PP had densities of 0.796 g/cm3 and 0.786 g/cm3; kinematic viscosities of 2.373 mm2/s and 2.115 mm2/s, dynamic viscosities of 1.889 mPas and 1.856 mPas; boiling point ranges of 119–364 °C and 148–355 °C; and cetane indices of 46 and 63, respectively. The characteristics of HDPE and PP pyrolytic sample oils are similar to conventional transportation fuel.
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    Transforming corn stover to useful transport fuel blends in resource-limited settings
    (Energy Reports, 2021) Munu, Nicholas; Banadda, Noble; Kiggundu, Nicholas; Zziwa, Ahamada; Kabenge, Isa; Seay, Jeffrey; Kambugu, Robert; Wanyama, Joshua; Schmidt, Albrecht
    Development of local technologies is crucial to the sustainable energy agenda in resource-limited countries and the world. Strengthening local green technologies and promoting local utilization will reduce carbon emissions that could be generated during transportation and delivery of green products from one country to another. In this paper we developed bio-oil/diesel blends using a low-tech pyrolysis system designed for smallholder farmers in developing countries and tested their appropriateness for diesel engines using standard ASTM methods. Corn stover retrieved from smallholder farmers in Gayaza, Uganda were pyrolyzed in a batch rocket stove reactor at 350 ◦C and liquid bio-oil harvested. Bio-oil chemical composition was analyzed by Gas Chromatography equipped with Flame Ionization Detector (GC-FID). Bio-oil/diesel emulsions in ternary concentrations 5%, 10% and 20% bio-oil weight were developed with 1% concentration of sorbitan monolaurate as an emulsifier. The bio-oil/diesel emulsions and distillates had property ranges: specific gravities at 15 ◦C 827.4–830.7 kg m−3, specific gravities at 20 ◦C 823.9–827.2 kg m−3, kinematic viscosities at 40 ◦C 3.01–3.22 mm2/s, initial boiling points 140–160 ◦C, final boiling points 354–368 ◦C, and calculated cetane indexes 56.80– 57.63. These properties of the bio-oil/diesel blends and their distillates compare well with standard transportation diesel fuel. The emulsion distillates meet the standard requirements for automotive diesel in East Africa.