Biosystems Engineering

Permanent URI for this community

http://localhost:4000/handle/20.500.14270/186

Browse

Now showing 1 - 20 of 29

Agriculture 4.0: The Promises for Sustainable Agricultural and Food Systems
(Busitema University, 2021-01) Bongomin, Ocident; Okello, Collins; Ocen, Gilbert Gilibrays; Tigalana, Dan
The transformative power of industry 4.0 in agricultural and food systems (Agri-food) can be attested from the explosive disruption of agricultural production infrastructures such as connected farms, new farm equipment, and connected tractors and machines which is well-known today as Agriculture 4.0 or Agri-food 4.0. The driving force behind the emergence of Agriculture 4.0 is the dire need to increase efficiency, productivity and quality in agri-food systems, and environmental protection. This has gained attention of many researchers in the recent past and thus, making Agriculture 4.0 a buzzword among the academic literature today. Despite the fact that a number of studies have covered the applications of several disruptive technologies in agri-food, the key technologies that are transforming the agri-food have been ill-defined. Therefore, the present paper aimed at identifying the key disruptive technologies and highlighting their application areas in agri-food. Massive exploratory literature search was conducted on the published papers obtained from the electronic databases including Scopus, ScienceDirect, Wiley, Emerald insight, Taylor & Francis, and Springer. The applications of 11 disruptive technologies in agri-food were analyzed based on 119 published papers. The results showed that 5 key disruptive technologies including Internet of things, Drones, Blockchain, Big Data, and Robotics are emblematic of Agriculture 4.0 epoch. The application areas of these technologies in agri-food are clearly highlighted. The present study revealed the need for extensive research to expand the application areas of the disruptive technologies in agri-food.
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.
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.
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.
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
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
Effects of sawdust and adhesive type on the properties of rice husk particleboards
(Elsevier, 2022-11-17) Olupot, Peter Wilberforce; Menya, Emmanuel; Lubwama, Festo; Ssekaluvu, Lawrence; Nabuuma, Betty; Wakatuntu, Joel
This study set out to investigate the effects of adhesive type, rice husk and sawdust proportions on the properties of composite particleboards. Specimens of 200 × 200 × 24 mm were made by blending 500 g of rice husks with each adhesive type at a mass ratio of 1:1. The rest of the specimens of similar dimensions were prepared with addition of sawdust in the range of 10–40 wt%, while maintaining the ratio of biomass particles to adhesive at 1:1. Three commercial synthetic adhesives Fevicol (FV), Ponal (PA) and woodfix (WF) were used. The particle adhesive mixtures were molded into a mat which was subsequently cold pressed at 10 MPa and left to dry in air. Density, water absorption (WA), linear expansion (LE), thickness swelling (TS), modulus of elasticity (MOE), modulus of rupture (MOR) and screw holding capacity of the specimens were evaluated. Adhesives were found to have over 42% solid content, with similar liquid constituents but in varying proportions. FTIR library search for the spectra of FV, PA, and WF revealed correlations of 82.5%, 78.6%, and 50.2%, respectively with polyvinyl acetate. The developed boards had a density of 510–610 kg/m3, MOE 13–26 MPa, TS 9–31%, and LE 3–7%. These properties suit them for furniture boards and soundproofing. The properties improved with the increasing proportion of sawdust. FV and PA-bonded particleboards exhibited higher stability and strengths than WF-bonded particleboards due to higher concentrations of polyvinyl-acetate in the latter. Blending 40 wt% sawdust, 10 wt% rice husk with 50 wt% of either FV or PA showed better prospects.
ENVIRONMENTAL BENEFITS OF VALORISING CATTLE MANURE FOR HOUSEHOLD COOKING ENERGY IN UGANDA
(CISA Publisher, 2014-11-20) Okello, C.; Pindozzi, S.; Faugno, S.; Boccia, L.
This study employed the Life Cycle Assessment (LCA) methodology to evaluate the environmental impacts of utilizing cattle manure as a substrate for biogas generation for cooking energy in Uganda. Results of the study showed that biogas energy systems based of cattle manure has potential environmental benefits in comparison to charcoal produced from natural forests. Under baseline scenario, without recycling of slurry as fertilizer, the biogas system leads to total environmental impacts of over 80% less than that of charcoal system. When slurry is utilized as substitute mineral fertilizers, the environmental impact of biogas system was found to be less than that of charcoal by close to 95%. The study further showed that that use of biogas could lead to considerable reduction on human health impacts compared to charcoal. In conclusion, utilization of cattle manure for biogas production has potential benefit of reducing the environmental impacts due to charcoal production and use in Uganda.
Experimental Evaluation of Manure Evaporation in The Paddock for a Management Algorithm Development
(Academia, 2012-07) Pindozzi, Stefania; Faugno, Salvatore; Okello, Collins; Boccia, Lorenzo
The aims of this study was to evaluate the possibility of reducing the weight of manure in paddocks by natural evaporation according to an appropriate management plan. The weight of buffalo manure was recorded by an experimental platform equipped with load cells and installed within the paddock. The data was used for assessing the real evaporation of manure in situ. A model for predicting manure evaporation was developed by adapting a soil evapotranspiration model. On the basis of the model an optimal management strategy was established, which corresponds to minimizing the use of the scraper from the 100th day of the year (DOY) to the 250th DOY. This lead to a potential reduction in weight of the manure by 650 kg/m2/year which corresponds to management cost reduction of about 30%. This approach is effective for reducing the bulkiness of buffalo manure for which the spreading costs per kg of nitrogen and the fuel needs for land application is very substantial considering its low nitrogen content of about 2 mg/m3.
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.
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.
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.
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.
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.
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.
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.
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.
Optimization of roughing filtration unit for a handwashing wastewater recirculation point-of-use system
(IWA PUBLISHING COMAPANY, 2022-11-22) Olupot, Peter Wilberforce; Menya, Emmanuel; Jjagwe, Joseph; Wakatuntu, Joel; Román, Franz; Hensel, Oliver
A downward roughing filter unit consisting of silica sand as the filter medium was optimized for performance towards removal of turbidity and suspended solids from handwashing wastewater. Design-Expert software was employed to optimize media particle size, filter depth, and flow rate. Linear and quadratic models were found to best fit the responses of turbidity and suspended solids removal, respectively. Particle size and flow rate were the only parameters with significant effects on the removal of turbidity and suspended solids. Optimal conditions were found to be media particle size 0.6 mm, filter depth 12 cm, and flow rate 0.3 Lmin 1 , corresponding to removal efficiencies of 62 and 67% for turbidity and total suspended solids (TSS), respectively, as predicted by the model. Validation of the model at optimal conditions resulted in turbidity and TSS removal of 55 and 53%, respectively. Additionally, removal efficiencies of the roughing filter towards apparent colour, true colour, biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) from handwashing wastewater were 56, 20,32, and 5%,respectively. Overall, although the turbidity of filtered water was .50 NTU, the reduction achieved by roughing filtration is a significant step in enhancing the performance of water treatment processes downstream, including filtration and adsorption by slow sand filters and activated carbon, respectively.
Production and Characterization of Paper from Banana Stem Fibre: Optimization Using Box-behnken Design (BBD)
(Taylor & Francis, 2023-03-22) Yiga, Vianney Andrew; Lubwama, Michael; Opio, James; Menya, Emmanuel; Nono, Denis; Nalubega Lubwama, Harriet
Banana stem is a known alternative to wood for the production of pulp and paper. During the production of paper, it is extremely important to save costs and time while at the same time enhancing the quality of produced paper. In the present study, the paper was developed from banana stem fiber by optimizing its density. Response surface methodology (RSM) using Box-Behnken design (BBD) was used to determine the optimum blending parameters of the developed papers. The influence of banana stem fiber amount (250-1000 g), water amount (1-2 litres), and blending time (5-10 min) on paper density was analyzed using the software Stat-Ease 360, Version 13. The optimum conditions of banana stem fiber amount, water amount, and blending time to achieve a density of 675.75 g/m3 were determined as 461.83 g, 1.31 liters, and 8.53 min, respectively. ANOVA results revealed that the quadratic model best fits the density response, with blending time and banana stem fiber amount as the most significant model terms. Linear effects were more predominant than quadratic and interaction effects. The developed density model was in close agreement with experimental findings with an R2 value of 0.9748. The developed paper had cellulosic contents, with volatiles as high as 82.11%wb and 2.11%wb ash composition. Future works on the thermal properties of paper are encouraged.

Browse

Browsing Biosystems Engineering by Title

Results Per Page

Sort Options