Research Articles

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Experimental tests on a new harvesting system for Burley tobacco
(Page Press, 2013-09-12) Faugno, Salvatore; Okello, Collins; Infascelli, Roberta; Audino, Francesca; Ardito, Luca; Pindozzi, Stefania
The globalization of the tobacco production has led to a drop in com petitiveness of the Italian tobacco on the world market. Burley is the main variety of tobacco cropped in Campania region of Southern Italy. Its leaves have to be sewn, in the curing phase. Aim of this work is to show the results of the implementation of a new harvest machine pro totype. Basically, the machine used for Bright tobacco, totally mechan ical harvested, which doesn’t need to be sewn because it requires an indirect-fire treatment into the curing furnaces. The machine was modified in order to mechanize harvesting of Burley tobacco, and test ed on four cultivars of Burley tobacco under three different planting layouts. The Burley tobacco leaves can be harvested mechanically by pulling individual leaves off the stalk; leaves are then sorted and tied in bundles prior to sewing. A mechanical burley tobacco harvesting system was evaluated. This machine consists in realizing a leaves ori entation system based on the different weight between the leaf blade and the stalk enhanced by an air flow. The measurements taken were harvest timing, work capacity, and quality standards of the work car ried out. The results, in terms of user time, range from 6.67 h/ha to 7.80 h/ha while in terms of operational efficiency are between 88% and 89%. The average user capacity recorded for the four cultivars is equal to 0.14 ha/h, a value far from the one recorded for the same harvesting machine used for Bright tobacco (0.25 ha/h). The harvest timing capacity, range from 0.51 t/h to 0.99 t/h. The work productivity goes from 0.17 t to 0.33 t per hour of human unit respectively. The average number of detached leaves, depending on the cultivar, has been between 523 and 744. Concerning the leaf orientation, a general per centage of 73% was achieved.
Fast-growing exotic tree species as fuelwood alternative for refugees and host communities in Northern Uganda
(Research Square, 2022-06-15) Anywar, Decimon; Shaban, Kato Stonewall; Labeja, Richard Louis; Loki, Robert Okongo; Okello, Collins
The high demand for firewood and charcoal has exerted high pressure on the indigenous trees in Uganda. 10 Communities believe that the indigenous trees are better fuel sources despite limited evidence to support this claim. 11 This study was carried out in 2021 to evaluate the fuelwood properties of selected indigenous tree species in 12 comparison to three exotic tree species that have been promoted for use by refugees and host communities in 13 Lamwo District of Northern Uganda. Wood samples were collected from three different locations from the study 14 area in Lamwo District and transported to Gulu University for laboratory analysis of their physical and chemical 15 properties. Data were analysed using one way analysis of variance (ANOVA) at 5% level of confidence and the 16 means were separated using Tukey HSD test. Results showed that moisture content, fixed carbon, volatile matter, 17 and Fuel Value Index (FVI) did not significantly vary among the indigenous and exotic tree species. Fuel value 18 index was observed to be negatively correlated with moisture content of the wood, implying both species’ categories 19 retard in fuel quality when their moisture contents increases. Overall, the results show that there were no significant 20 differences in the FVI of all the indegeneous and exotic tree species investigated in this study. It is recommended 21 that fast-growing exotic species such as Eucalyptus grandis, Caliandra calothyrsus, and Senna siamea that are 22 grown in the region be promoted to ensure regeneration and reduction of pressure on the use of natural forest.
Assessment of nitrogen content in buffalo manure and land application costs
(Page Press, 2012-08-29) Faugno, Salvatore; Pindozzi, Stefania; Infascelli, Roberta; Okello, Collins; Ripa, Maria Nicolina; Boccia, Lorenzo
Buffalo (Bubalus bubalis) livestock for mozzarella cheese production plays a fundamental role in the economy of southern Italy. European and Italian regulations consider nitrogen content in buffalo manure to be the same as that of cattle manure. This study aimed to assess whether this assumption is true. The first aim of the study was to assess nitrogen con tent in buffalo manure. Samples were taken from 35 farms to analyse nitro gen and phosphorous concentration in the manure. Analysis confirmed a lower nitrogen concentration (2%) in buffalo manure. A secondary aim of the study was to evaluate whether manure application techniques that are apparently less suitable, e.g. splash plate spreader, could be feasible. The cost of different methods of land application of manure and their charac teristics were evaluated on the basis of one operational cycle. Considering losses for volatilisation, and taking into account cost assessment, the immediate incorporation of buffalo manure (nitrogen content 2%) is a suitable method of ammonia volatilisation. However, it is expensive and involves high fuel consumption in relation to the environmental benefit.
Applications of Drones and Image Analytics in Field Phenotyping: A Potential Breakthrough in Uganda’s Agricultural Research
(SSRN, 2022) Bongomin, Ocident; Lamo, Jimmy; Guina, Joshua Mugeziaubwa; Okello, ,Collins; Ocen, Gilbert Gilibrays; Obura, Morish; Alibu, Simon; Owino, Cynthia Awuor; Akwero, Agnes; Ojok, Samson
We are in the race against time to find new solutions amidst the threat of climate change, to increase food production by 70% to feed the ever-growing world population which is expected to double by 2050. Agricultural research plays astonishing roles in crop and livestock improvement through breeding programs and good agronomic practices to enable sustainable agriculture and food systems. The advanced molecular breeding or modern breeding technologies in genotyping have been well-embraced by most research institutions worldwide. However, phenotyping which plays great role in agricultural research and breeding programs has achieved little development or still a traditional method in most institutions across African countries. Noteworthy, the advancement of phenotyping has been gaining momentum and attracted a number of researchers in the recent past, this led to the coining of high-throughput phenotyping concept. Nevertheless, the comprehensive understanding of this concept remains limited in most research institutions in developing countries, especially Uganda. Therefore, the present review aimed to provide a summary of drone-based high throughput phenotyping used across different crops. The electronic literature search was conducted from non-academic and academic databases. The literature sources in the form of peer-reviewed journal articles, books, book sections, conference papers, thesis and dissertations, policy papers, organisation or company manuals, working papers, and reports were considered. In this review, the concepts of field phenotyping are discussed, drone classification and specifications are elaborated, the use cases of the drone-based high-throughput phenotyping are presented, drone imaging systems for phenotyping are discussed, and high-throughput image analytics method is explained. In this paper, it was found that cereals have been the most studied crop for drone based phenotyping application in academic literature. However, root crops were the list studied, hence, extensive research is needed for drone-based phenotyping adoption in root crops. Moreover, limited studies have been focused on the effect of drones’ operation parameters. Therefore, research focusing on the optimization of the drones’ performance is required.
Appraising Bioenergy Alternatives in Uganda Using Strengths, Weaknesses, Opportunities and Threats (SWOT)-Analytical Hierarchy Process (AHP) and a Desirability Functions Approach
(MDPI, 2014-02-26) Okello, Collins; Pindozzi, Stefania; Faugno, Salvatore; Boccia, Lorenzo
Poor access to clean and reliable energy technologies is a major challenge to most developing countries. The decision to introduce new technologies is often faced by low adoption rates or even public opposition. In addition, the data required for effective decision making is often inadequate or even lacking, thus constraining the planning process. In this study, a methodology for participatory appraisal of technologies, integrating desirability functions to the strengths, weaknesses, opportunities and threats (SWOT)-analytical hierarchy process (AHP) methodology was developed. Application of the methodology was illustrated with an example for participatory appraisal of four bioenergy technologies in Uganda. Results showed that the methodology is effective in evaluating stakeholder preferences for bioenergy technologies. It showed a high potential to be used to identify and rate factors that stakeholders take into consideration when selecting bioenergy systems. The method could be used as a tool for technology screening, or reaching consensus in a participatory setup in a transparent manner.
Indirect field technology for detecting areas object of illegal spills harmful to human health: application of drones, photogrammetry and hydrological models
(PAGEPress Publications, 2014) Capolupo, Alessandra; Pindozzi, Stefania; Okello, Collins; Boccia, Lorenzo
The accumulation of heavy metals in agricultural soils is a serious environmental problem. The Campania region in southern Italy has higher levels of cancer risk, presumably due to the accumulation of geogenic and anthropogenic soil pollutants, some of which have been incorporated into organic matter. The aim of this study was to introduce and test an innovative, field-applicable methodology to detect heavy metal accumulation using drone-based photogrammetry and micro rill network modelling, specifically to generate wetlands wetlands prediction indices normally applied at large catchment scales, such as a large geographic basin. The processing of aerial photos taken using a hexacopter equipped with fifth-gen eration software for photogrammetry allowed the generation of a digital elevation model (DEM) with a resolution as high as 30 mm. Not only this provided a high potential for the study of micro-rill processes, but it was also useful for testing and comparing the capability of the topographic index (TI) and the clima-topographic index (CTI) to predict heavy metal sedi mentation points at scales from 0.1 to 10 ha. Our results indicate that the TI and CTI indices can be used to predict points of heavy metal accumulation for small field catchments.
Stakeholders’ Perceptions of Agronomic Iodine Biofortification: A SWOT-AHP Analysis in Northern Uganda
(MDPI, 2018-03-24) Olum, Solomon; Gellynck, Xavier; Okello, Collins; Webale, Dominic; Odongo, Walter; Ongeng, Duncan; DeSteur, Hans
Agronomic biofortification (i.e., the application of fertilizer to elevate micronutrient concentrations in staple crops) is a recent strategy recommended for controlling Iodine Deficiency Disorders (IDDs). However, its success inevitably depends on stakeholders’ appreciation and acceptance of it. By taking Northern Uganda as a case, this study aimed to capture and compare the perceptions of seven key stakeholder groups with respect to agronomic iodine biofortification. Therefore, we employed a SWOT (Strength, Weaknesses, Opportunities & Threats) analysis in combination with an Analytical Hierarchy Process (AHP). Findings show that stakeholders (n = 56) are generally positive about agronomic iodine biofortification in Uganda, as its strengths and opportunities outweighed weaknesses and threats. Cultural acceptance and effectiveness are considered the most important strengths while the high IDD prevalence rate and the availability of iodine deficient soils are key opportunities for further developing agronomic iodine biofortification. Environmental concerns about synthetic fertilizers as well as the time needed to supply iodine were considered crucial weaknesses. The limited use of fertilizer in Uganda was the main threat. While this study provides insight into important issues and priorities for iodine biofortification technology in Uganda, including differences in stakeholder views, the application of the SWOT-AHP method will guide future researchers and health planners conducting stakeholder analysis in similar domains.
Testing the application of an automatic milking system on buffalo (Bubalus bubalis)
(PAGEPress, Italy, 2015-01-08) Faugno, Salvatore; Pindozzi, Stefania; Okello, Collins; Sannino, Maura
The automatic milking systems (AMS) have been deeply studied in dairy cows applications, but not in the case of buffaloes; although, a few applications to the species can be found in literature. The objec tive of this study is to compare some important functional aspects of AMS with the conventional milking systems. Aspects such as adapta tion of buffalo to AMS and the possible relationship between milking frequency and daily milk yield were evaluated. Two groups of Bubalus bubalis were reared in the same barn, in a farm located in Piana del Sele (SA) southern Italy. Fourty primiparous buffaloes were milked using an AMS, and at the same time another herd of 40 were milked twice a day using traditional milking system (tandem). The adaptation period of buffaloes to AMS was 2 months. Milking frequency with the AMS was significantly higher compared to the one of traditional meth ods (2.3±0.17 times/d vs 2 times/d). Daily milk yield with the AMS was observed to be significantly higher than with traditional milking sys tem (7.9±1.3 kg/d vs 6.9±1.06 kg/d). In this study, there was no signif icant relationship between the increase of daily milking frequency and daily milk yield. We can conclude that a positive AMS effect on daily milk yield and milking frequency is possible and so we can expect suc cessful applications of the AMS to dairy buffalo farms.
Using historical maps to analyze two hundred years of land cover changes: case study of Sorrento peninsula (south Italy)
(Taylor & Francis, 2015-08-14) Pindozzi, Stefania; Cervelli, Elena; Capolupo, Alessandra; Okello, Collins; Boccia, Lorenzo
Historical maps are effective sources of geographical information and useful for historical and territorial research. In this study, the examination of landscape dynamics on the basis of historical maps over a period of more than 200 years was conducted. The study area is Sorrento peninsula and part of the near Sarno river basin in South Italy. This study provides a general framework for the assessment of the overall quality and accuracy of historical maps. The application of the methodology used in this specific case study can contribute to a better understanding of the dynamics of the landscape in the long term. The derived knowledge can be applied in the planning of the landscape in order to implement correct conservation strategies. The comparison was made on four maps 1817, 1875, 1960, and 2006. Geodetic accuracy of the sheet maps of 1817 and 1875 offer a right basis for a macro analysis of land cover dynamics, evaluating conversion from one land cover category to another. Main trans formation, identified in the period between 1875 and 1960, was the disappearance of vineyards, which covered 25% of the total study area in 1875. Agricultural areas increased in this period to cover 57% of the total area.
Techno-economic assessment of municipal solid waste gasification for electricity generation:
(CIGR Journal, 2015-10-14) Kivumbi, Bernard; Olwa, Joseph; Martin, Andrew; Menya, Emmanuel
This study was aimed at assessing the techno-economic potential of municipal solid waste (MSW) generated in Kampala City for electricity production through gasification. The quantity, characteristics, and gasification parameters were determined. In addition, the gasifier-engine system components were sized, and an economic analysis was conducted to obtain the net present value (NPV) and the payback period. This study found that 523 t/d of MSW is collected in Kampala City. The biomass component of MSW was found to be 459.5 t/d with a moisture content of 71.09% on an as-received basis. The physical characteristics of the gasified biomass included 11.8% moisture content, 88.2% total solids, 25.9% ash content and 57.7 kg/m3bulk density. The resulting normalized producer gas constituted 11.64% H2, 13.70% CO, 16.09% CO2, 54.12% N2, 4.45% CH4and a lower heating value (LHV) of 4.75 MJ/Nm3. The design fuel flow rate of 0.23 kg/s, specific gasification rate (SGR) of 5089.29 kg h-1m-2and specific energy demand of 42.75 GJ m-2h-1were obtained. This yields a net electrical power output of 425.17 kW with an overall efficiency of 15.6%. The net annual electricity generation from a single gasifier-engine system was found to be 2.97 GWh/a. The economic analysis for this system worth $887 333 of investment cost yielded a payback period of 6.57 years while the NPV at 6% interest rate was found to be nine years with a value of $316 47.
Effects of Mulching on Soil Hydro-Physical Properties in Kibaale Sub-catchment, South Central Uganda
(Science and Education Publishing, 2015-10-11) Kakaire, Joel; Makokha, George L.; Mwanjalolo, Majaliwa; Mensah, Albert K; Menya, Emmanuel
Mulching is one of the major soil and water conservation measures applied for conserving soil moisture and modifying soil physical and chemical environment. The study aimed at assessing the effect of mulching on soil hydro-physical properties in Kibaale sub-catchment in South Central Uganda. Samples were obtained between 0-20 cm depths and under 0, 5, 10 and 15 cm mulch thickness levels. The experiment involved 3 farmers and 4 treatments of corn residue mulch thicknesses each replicated thrice on each of the farmer sites. The main parameters of study were; bulk density, saturated hydraulic conductivity (Ksat) and water retention. The parameters were determined using core method, constant head method and pressure plates’ method respectively. Laboratory data was statistically analyzed using Analysis of Variance (ANOVA) from Genstat software Edition 4 and the means differentiated using 5 % least significant difference (LSD). The application of mulch significantly improved all the soil hydro-physical properties that were studied (bulk density, Ksat, field capacity, wilting point, porosity, soil organic matter (SOM), mean weight diameter (MWD) after two seasons. The level of improvement was highest with 10 cm mulch thickness while Ksat, porosity and SOM varied significantly (P< 0.05) with mulch thickness. The study recommends the use of 10 cm mulch thickness. This study provides information to stakeholders such as agricultural experts, watershed managers, farmers and policy makers which will help in formulating guidelines on how to incorporate mulching as an effective method for soil and water conservation in the Sub-catchment
Investigating the effect of different loading densities on selected properties of dried coffee using a GHE dryer
(CIGR Journal, 2023-09) Menya, E.; Komakech, A. J.
Despite coffee being one of the leading cash crops in Uganda contributing 20%-30% of the total export earnings, it is mainly dried on bare earth surfaces hence its drastic decline in quality. A possible alternative solution is the utilization of the greenhouse effect (GHE) solar dryer. This research was aimed at investigating the effect of different loading densities on selected properties of dried coffee using a GHE dryer that was designed and constructed at Makerere University Agricultural Research Institute Kabanyolo (MUARIK). The research involved determining the drying time for the loading densities of 5, 10 and 20 kg m-2 as well as analyzing the coffee quality at the end of the drying period. Three experimental runs were set up in the months of June and July which experienced an average ambient temperature of 23.28 (±2.33)oC and an average dryer temperature of 35.68 (±13.85)oC. The average drying time for the freshly harvested Robusta coffee at 61.3 (±1.36)% wb was 10 days for 5 kg m-2, 11 days for 10 kg m-2 and 12 days for 20 kg m-2. The loading of 20 kg m-2 resulted in an even roast with fair+ for body and flavour, while 5 and 10 kg m-2 loadings resulted in a silver skin roast with fair body and flavour. For this particular research, the loading density of 20 kg m-2 yielded the best results from the coffee quality analysis. The loading densities of 5 kg m-2 and 10 kg m-2 could not yield the best results due to case hardening of the outer surfaces of the coffee beans which compromised the body and flavour of the coffee.
Factors affecting adoption of mulching in Kibaale sub-catchment, South Central Uganda
(International Journal of Sustainable Agricultural Management and Informatics, 2016) Kakaire, Joel; Mensah, Albert Kobinah; Menya, Emmanuel
Mulching is one of the major soil and water conservation measures applied for conserving soil moisture and modifying soil's physical environment. The study aimed at determining the factors which influence the adoption of mulching in the Kibaale sub-catchment, Uganda. 100 structured questionnaires; key informant interviews and observation were used to obtain the socio-economic and institutional data. To determine the factors affecting the adoption of mulching, descriptive statistics, and factor analysis were used. Chi-square (P ≤ 05) was used to establish the relationship between the identified factors and adoption. Using the chi-square test, the study also identified the Education level of household head, household size, accessibility to farmland, and marital status as the major factors that significantly affected adoption of mulching. The community leaders should ensure that the members attain some level of education and ensure that the land owned by individuals is within their periphery of management and control.
Production and performance of activated carbon from rice husks for removal of natural organic matter from water:
(Elsevier, 2017-11-02) Menya, E.; Olupot, P.W.; Storz, H.; Lubwama, M.; Kiros, Y.
Adsorption by activated carbon has great potential to improve natural organic matter (NOM) removal from water. However, the high production and regeneration costs limit its wide scale application. To address these limitations, research efforts have been focused on finding low-cost materials that can be transformed into activated carbon. Rice husk is one of such material of research focus, especially in developing countries, where over 96% of rice husks are generated globally. Although numerous investigations have been made concerning the production of activated carbon from rice husks, the existing scientific information still remains widely scattered in the literature. Furthermore, the scientific information regarding the performance of rice husk-activated carbon during NOM removal from water still remains poorly documented. This review article, therefore, provides ample information on efforts made by various researchers concerning the production of activated carbon from rice husks and its adsorption performance in relation to NOM removal from water. The properties and pretreatment of rice husks in relation to the production of activated carbon are discussed. Activation of rice husks by physical and chemical methods under numerous conditions is reviewed. Factors affecting NOM adsorption by activated carbon are briefly discussed. The adsorption performance of rice husk activated carbon is also reviewed with respect to NOM removal from water, and where possible compared with other source-derived activated carbons. The data from the literature revealed that NOM removal by rice husk activated carbon can be as effective as commercial activated carbon. Consequently, rice husk-activated carbon has the potential to serve as an alternative to commercial-activated carbon.
Optimization of pyrolysis conditions for char production from rice husks and its characterization as a precursor for production of activated carbon
(Springer, 2019-03-13) Menya, E.; Olupot, P. W.; Storz, H.; Lubwama, M.; Kiros, Y.; John, M. J.
Response surface methodology was employed to optimize pyrolysis conditions for the production of char with maximum yield, fixed carbon content, and minimum ash content from Uganda’s New Rice for Africa (NERICA) 1 rice husk variety. The aim was to obtain rice husk char with more suitable properties as an activated carbon precursor. Mathematical models were developed to explain the relationships between the experimental responses and the pyrolysis parameters of temperature (400–600 °C), heating rate (10–25 °C min−1), and heating period (60–120 min). The optimized rice husk char was further characterized for elemental and proximate compositions, thermal behaviour, specific surface area, as well as surface functional groups. Results from the analysis of variance (ANOVA) revealed that the quadratic model best fits each of the responses. Pyrolysis temperature had the greatest influence on each of the responses, followed by heating period, and lastly heating rate. Optimum pyrolysis conditions were found to be temperature (406 °C), heating rate (10 °C min−1), and heating period (60 min), resulting in char yield, fixed carbon, and ash contents of 35.26, 55.39, and 35.01% dry basis, respectively. Compared to raw rice husk, the resulting rice husk char was found more suited as activated carbon precursor, due to its enriched carbon content (60.35%) and specific surface area (123.9 m2g−1). Thermogravimetric analysis of the rice husk char revealed that thermal activation temperatures were higher than 400 °C may be required to considerably devolatilize the char, forming a more porous activated carbon.
Effect of alkaline pretreatment on the thermal behavior and chemical properties of rice husk varieties in relation to activated carbon production
(Springer, 2019-07-19) . Menya, E; Olupot, P. W.; Storz, H.; Lubwama, M.; Kiros, Y.; John, M. J.
Thermal behavior and chemical properties of selected raw and NaOH-pretreated rice husk varieties were investigated. NaOH- pre treatment process involved soaking 5 g rice husk samples in 40 mL of 2%w/v NaOH, shaking (400 rpm) and heating (50 C) for 3 h. NaOH- pretreated samples were water-washed, oven-dried, and milled for use in the determination of their thermal behavior and surface functional groups. Alkaline wash water was also analyzed for sugar components. Thermal decomposition temperatures, degradation rates, and the subsequent mass losses varied from one rice husk variety to another. These thermal properties increased after NaOH pretreatment of the rice husk varieties, reducing their char yields (17.1–20.4% db). These changes mainly had to do with the lignin, hemicellulose, and ash removal from the rice husk varieties, as confirmed by their FTIR analysis, as well as by the sugar composition analysis of their alkaline wash-water. Consequently, the FTIR spectra differed between the raw and NaOH-pretreated rice husk varieties
Experimental evaluation of rice husk ash for applications in geopolymer mortars
(Keai publishing, 2021-02-26) Ogwanga, G.; Olupot, P.W.; Kasedde, H.; Menya, E.; Storz, H.; Kiros, Y.
Rice husks obtained from upland and lowland rice varieties were characterized by the composition and content of ash. Each of the rice husk varieties was fired at temperatures of 600, 800, and 900 °C for a soaking period of 3 h. The resultant rice husk ash was analyzed for oxide composition and crystallinity using X-ray fluorescence and diffraction techniques, respectively. The generated amorphous ash with the highest silica content, together with metakaolin, aggregate, water, and an alkaline activator was employed to formulate geo-polymer mortar prisms according to the standard EN 196–1. Results showed that the content of ash in the varieties ranged from 18.3% to 28.6% dry basis. Out of this, 89 wt%–96 wt% was silica, with amorphous and crystalline forms of silica obtained at 600 °C and 900 °C, respectively, regardless of the rice variety. However, at 800 °C, the silica in the generated ash exhibited both amorphous and crystalline forms. The amorphous ash generated at 600 °C was used in the formulation of geopolymer mortars. The compressive and flexural strength of the formulated mortar after 7 days of curing was 1.5 and 1.3 MPa, respectively. These results reveal the firing protocol to form pozzolanic ash, with potential applications in mortar production.
Synthesis and Application of Granular Activated Carbon from Biomass Waste Materials for Water Treatment :
(Keai publishing, 2021-04-06) Jjagwe, Joseph; Olupot, Peter Wilberforce; Menya, Emmanuel; Mpagi Kalibbala, Herbert
There is an increased global demand for activated carbon (AC) in the application of water treatment and purification. Water pollutants that have exhibited a greater removal efficiency by AC included but are not limited to heavy metals, pharmaceuticals, pesticides, natural organic matter, disinfection by-products, and microplastics. Granular activated carbon (GAC) is mostly used in aqueous solutions and adsorption columns for water treatment. Commercial AC is not only costly but also obtained from non-renewable sources. This has prompted the search for alternative renewable materials for AC production. Biomass wastes present a great potential for such materials because of their availability and carbonaceous nature. This, in turn, can reduce the adverse environmental effects caused by poor disposal of these wastes. The challenges associated with biomass waste-based GAC are their low strength and attrition resistance which make them easily disintegrate under the aqueous phase. This paper provides a comprehensive review of recent advances in the production of biomass waste-based GAC for water treatment and highlights future research directions. Production parameters such as granulation conditions, use of binders, carbonization, activation methods and their effect on textural properties are discussed. Factors influencing the adsorption capacities of the derived GACs, adsorption models, adsorption mechanisms, and their regeneration potentials are reviewed. The literature reveals that biomass waste materials can produce GAC for use in water treatment with the possibility of being regenerated. Nonetheless, there is a need to explore 1) the effect of preparation pathways on the adsorptive properties of biomass-derived GAC, 2) sustainable production of biomass-derived GAC based on life cycle assessment and techno-economic analysis, and 3) adsorption mechanisms of GAC for removal of contaminants of emerging concerns such as microplastics and unregulated disinfection by-products.
Development and appraisal of hand wash-wastewater treatment system for water recycling as a resilient response to COVID-19
(Elsevier, 2021-07-28) Olupot, Peter Wilberforce; Menya, Emmanuel; Jjagwe, Joseph; Wakatuntu, Joel; Kavuma, Tonny; Wabwire, Andrew; Kavuma, Steven; Okodi Mcmondo, Samuel; Nabuuma, Betty; Mpagi Kalibbala, Herbert
In this work, results from characterization of handwashing wastewater from selected stations in Kampala City, Uganda, revealed that handwashing wastewater did not meet permissible international standards for wastewater discharge to the environment. The ratio of BOD5 to COD of ˂ 0.5 implied that handwashing wastewater was not amenable to biological treatment processes. Turbidity of ˃ 50 NTU pointed to the need for a roughing filter prior to slow sand filtration. Subsequently, a handwashing wastewater treatment system consisting of selected particle sizes of silica sand, zeolite, and granular activated carbon as filtration and/or adsorption media was developed and assessed for performance towards amelioration of the physicochemical and biological parameters of the handwashing wastewater. Treated water from the developed wastewater treatment system exhibited turbidity of 5 NTU, true color of 10 Pt-Co, apparent color of 6 Pt-Co, and TSS of 9 mgL-1, translating to removal efficiencies of up to 98.5%, 98.1%, 99.7%, and 96.9%, respectively. The residual total coliforms and E. coli of 1395 and 1180 CFU(100 mL)-1 respectively, were totally eliminated upon disinfection with 0.5 mL NaOCl (3.5% wt/ vol) per liter of treated wastewater. The treated water was thus suitable for recycling for handwashing purposes as opposed to letting handwashing wastewater merely go down the drain. This approach provides a resilient response to COVID-19, where communities faced with water scarcity can treat and recycle handwashing wastewater at the point of washing. It thus enables more people to have the opportunity to practice handwashing, abating the high risks of infection, which could otherwise arise.
Optimization of pyrolysis conditions for production of rice husk-based bio-oil as an energy carrier
(Elsevier, 2023-11-09) Wakatuntu, Joel; Olupot, Peter Wilberforce; Jjagwe, Joseph; Menya, Emmanuel; Okure, Mackay
Bio-oil is an eco-friendly energy source with potential to substitute fossil-derived fuels. This study optimized pyrolysis conditions for production of bio-oil from rice husks. Response surface methodology based on central composite design was employed to maximize bio-oil yield and high heating value (HHV) while minimizing water and ash contents. The pyrolysis process conditions were; temperature (400–650 ◦C), heating rate (6000–9750 ◦Ch-1), and holding time (600–1800 s). Analysis of variance revealed that the linear model best fits the responses of bio-oil yield and water content. On the other hand, the quadratic model best fits the responses of HHV and ash content. Pyrolysis temperature had the greatest influence on each of the studied responses, followed by holding time and lastly heating rate. Optimum pyrolysis conditions were found to be; temperature (650 ◦C), heating rate (9750 ◦Ch-1), and holding time (1800 s), leading to bio-oil yield, HHV, water, and ash contents of 38.13%, 23.40 MJ/kg, 18.27%db, and 0.16%db, respectively. These results fall in the range of standard quality values for bio-oil in published literature where >15 MJ/kg, 20–30%, 0.15–0.25% are the recommended ranges for HHV, water, and ash contents, respectively. Results from the FTIR spectroscopy revealed that phenolic compounds contributed the most to bio-oil composition. Phenolic compounds positively influenced the quality of bio-oil due to their high calorific values. Gas chromatograph and mass spectrometry results showed peaks continuing to spill up to the maximum retention time indicating good thermal stability and bio-oil quality.

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