School of Engineering (SEng.) Collections
http://hdl.handle.net/10570/180
2024-03-28T09:06:35ZActivated carbon from cassava peels for removal of active pharmaceutical ingredients from wastewater.
http://hdl.handle.net/10570/10785
Activated carbon from cassava peels for removal of active pharmaceutical ingredients from wastewater.
Kayiwa, Ronald
Over the past decade, cassava production has been accelerated, ranking as the 5th most produced food crop at an estimated global production of 298.8 million metric tons by 2020 as per the Food and Agriculture Organization (FAO). With the 10-20% peel composition of the tuber weight, the implied cassava peel production ranges between 29.88 to 59.76 million metric tons. The main application of cassava peels is Papering animal feeds. However, this is limited due to the peels’ low protein content (<6%). Throughout the past decade, cassava peels have been valorized into activated carbons with qualities able to curb recalcitrant adsorbates like heavy metals, dyes, and arsenics. However, the application of cassava peel-based activated carbon in the adsorption of pharmaceuticals from wastewater has not been explicitly studied. This study aimed at modifying the valorization processes of cassava peels into activated carbon capable of removing active pharmaceutical ingredients from wastewater. This involved, (i) characterization of peels of six predominant cassava varieties (NAROCAS 1, NAROCAS 2, NASE 1, NASE 3, NASE 14, and NASE 19) grown in Uganda for production of activated carbon (ii) optimization of activated carbon production conditions from the most viable peel variety, (iii) characterization of the wastewater from effluents of pharmaceutical manufacturing plants (PMPs) and wastewater treatment plants (WWTPs) in Kampala for active pharmaceutical ingredients (APIs), and (iv) determination of the performance of the produced activated carbon towards the removal of active pharmaceutical ingredients from wastewater.
All the six cassava peel varieties were potential activated carbon AC precursors with ash contents as low as <5% dry basis and fixed carbon of 13.78–15.34%. NAROCAS 1 cassava peel variety was the most suitable due to its lowest ash content (1.93%), high elemental carbon content (59.40%), balanced volatile matter (81.93%), and fixed carbon content (13.78%). Pre-leaching of the peels using 1– 4% NaOH revealed a more remarkable effect on the increase of volatile matter and fixed carbon (1.00% and 3.56% respectively) than ash content reduction (0.51%). The optimal process conditions for the production of physically activated carbon were found to be a temperature of 782 °C and a heating time of 148 mins resulting in a specific surface area of 756.42 m2g-1, and a yield of 4.57%. The best chemically activated carbon resulted from a 4.0%w/v NaOH pre-leaching at 50 °C and a 5:2 KOH: peel ratio of 5:2 (mass basis) activation at 60 °C for 3 hours. This was followed by carbonization at 780 °C for 2 hours resulting in a 42% yield, total pore volume of 0.756 cm3g-1, and the highest ever reported specific surface area for cassava peel activated carbon (CPAC) of 1684 m2g-1. The concentration ranges of the selected APIs targeted in this study were <LOD – 4.75, <LOD –1.37, <LOD – 1.17, and 0.28 – 19.55 for diclofenac, sulfamethoxazole, carbamazepine, and clarithromycin, respectively, in effluents of WWTPs whereas in treated wastewater from PMPs concentrations were <LOD, <LOD – 0.23, 5.30 – 7.4, <LOD – 0.14, and 0.12 – 4.53 mgL-1 for losartan, diclofenac, sulfamethoxazole, carbamazepine, and clarithromycin respectively. Through a batch experimental setup, the produced AC adsorbed 86.00, 58.00, and 68.50 % of carbamazepine (CBZ), clarithromycin (CLN), and trimethoprim (TRM) from effluent wastewater whereas from milli q water, 94.25, 73.50, and 84.5 % respectively were removed at an initial concentration of 20 mgL-1 for all the APIs and CPAC dosage of 2.0 gL-1. The maximum adsorption capacities attained were 1.487, 25.907, and 84.034 mgg-1 for CLN, TRM, and CBZ respectively exhibiting potential for CPAC to sequestrate APIs from water systems. The techno-economic analysis of a cassava peel-based AC manufacturing plant of 1 tonne/day capacity gave a 35% return on investment, a net present value of $ 648,331, and a Pay-back period of approximately 2 years. This study presents for the first time, the application of cassava peel-activated carbon in the treatment of wastewater with active pharmaceutical ingredients as the main target contaminants.
A thesis submitted to the Directorate of Research and Graduate Training in partial fulfillment of the requirements for the award of the degree of Doctor of Philosophy of Makerere University.
2022-08-01T00:00:00ZAdaptation of the smart methodology to value management of the Uganda School Facilities Grant programme
http://hdl.handle.net/10570/3982
Adaptation of the smart methodology to value management of the Uganda School Facilities Grant programme
Kivumbi, A.D.
In any construction project, the aim of the developer is to maximize profit at minimum cost within the context of the quality possible as per the required specifications. Therefore, loss of resources should be minimized as much as possible, especially in such a crucial project as the School Facilities Grant (SFG) project, so that there is perceived cost-effectiveness.
This dissertation considers the adaptation of the Simple Multi-Attribute Rating Technique (SMART) methodology, which is easy and useful for varied decision makers, to Value Management (VM) of the Uganda SFG primary school classroom construction programme in Mukono and Kampala districts. Application of SMART involves interacting with various stakeholders and then holding a key stakeholder workshop through which a shared understanding of the issues under consideration can be reached. This understanding is translated into an information pack developed for use in the workshop. A Value Tree is used as the tool for consideration of opinions by the stakeholders. The allocation of importance weights to the lower – order attributes of the tree provides a rational basis for determining the best-valued Design Option. Each Option is assessed against each of the identified attributes in the evaluation, the assessment being performed by a process of scoring the n Option against each attribute.
A Standard Analysis Form is used and the ratio of Aggregated Utility Rating to Estimated Capital Cost, U / C of the ith Design Option calculated, with the highest value of U /C providing the rational choice. The testing of the sensitivity of the outcome of the rating process to marginal changes in the key variables, or Sensitivity Analysis, is then carried out. This was applied to Value Management of the SFG school construction in the two mentioned districts. A brainstorming session was later held to generate a variety of ideas that would also enable the evaluation of the practicality of the identified Option.
The SMART methodology was found to be applicable to the SFG programme with the stakeholders being easily comfortable with the common understanding reached. They were also able to make some rational decisions/evaluations of the SFG Design Options. A new policy could be formulated for the programme and the model that has been obtained could be adapted for use for other projects.
A Thesis submitted to the Directorate of Research and Graduate Training in partial fulfillment of the requirements for the award of the Degree of Master of Science in Civil Engineering of Makerere University
2010-10-01T00:00:00ZAn Advanced protection scheme to avert blackouts due to transmission network overload.
http://hdl.handle.net/10570/7596
An Advanced protection scheme to avert blackouts due to transmission network overload.
Rwendeire, Andrew
The transmission and distribution networks suffer various overloads which have reduced power availability and utility income generation. Some networks employ frequency monitoring with Under Frequency Load Shedding to ensure system stability. However, other conditions that threaten power system stability like the loss of a tie line, overload trip of power transformers, distribution and transmission lines need to be monitored and prevented by implementing protection schemes which automatically shed off the extra load. This will not only improve reliability and continuity of service but also fast decision making to reduce the blackout zone and downtime. This paper presents a load management scheme that performs automatic load shedding and feeder restoration by strictly following the set threshold values using PCM600, an ABB tool. The logic configuration from PCM600 was validated and the Generic Object Oriented Substation Events (GOOSE) report published. The Configured IED Description (CID) file from each IED (in PCM600) was saved in Substation Configuration Language (SCL) format and imported into IEDScout to simulate the IEC61850 communication. The developed model was applied to a case study on the Ugandan transmission network to achieve a 500ms GOOSE messaging sequence on the station bus. IEDScout demonstrated a station-bus traffic data flow rate of 2 kbps responsible for CB commands and status update. The traffic on the Ethernet cable was captured and analyzed using WireShark, a graphic user interface network protocol, two data packets were sent every second through the Ethernet cable and 464 k bytes of data packets were sent as messages on the station bus during the simulation. The model was tested and was able to send a CB open command with in 2ms of overload threshold violation and when the transformer load was reduced, CB close command for load re-connection was sent with in 2ms. A cost benefit ratio of 1.647 was obtained. This model caters for very rare, non-continuous but possible and very catastrophic occurrences on the power system. Therefore, this paper provides an efficient solution to transmission line and transformer overload by automating downstream load-shedding and load restoration.
2018-08-24T00:00:00ZAnalyzing the effectiveness of gasifier-produced biochar as a soil amendment in the humid tropics
http://hdl.handle.net/10570/2179
Analyzing the effectiveness of gasifier-produced biochar as a soil amendment in the humid tropics
Deal, Christopher William
Biochar is the solid, carbonaceous byproduct from thermal treatment of biomass that is produced specifically for application to soils. Studies have shown that when biochar is added to soils it is able to increase yields, prevent erosion, and effectively store carbon for hundreds to thousands of years. Sizeable research has been conducted using biochar from traditional charcoal kilns as this is the method that maximizes biochar production. Biochar from gasification, however, has been relatively unexamined. The intent of this research, therefore, was to determine if gasifier-produced biochar would act as an effective soil amendment. The motivation behind this study was to create a valuable byproduct from gasification that would also allow the entire process to be considered “carbon-negative.” This investigation was designed to analyze the effectiveness of gasifier-produced biochar through a comparison with kiln-produced biochar. Two types of biomass – maize cobs and eucalyptus wood chunks – were used in the creation of biochar from a gasifier and traditional charcoal kiln. The biochar samples were combined with undisturbed soil from the Makerere University Agricultural Research Institute at Kabanyolo in a 45 day pot experiment to compare effects on plant growth. The experimental results show that, on average, soils amended with gasifier-produced biochar have higher yields than soils amended with kiln-produced biochar. The magnitude of this increase, however, was varied, and this variance was indicative of the sample‟s composition. Biochar composition varied across feedstocks, production methods, and even within samples from the same feedstock and production method. Results indicated that the characteristic with the greatest influence on soil productivity was the soluble ash content in the biochar. Soluble ash, when introduced to soils, helped to increase pH levels. Ugandan soils, like most soils in the humid tropics, are strongly acidic, and this increase in pH allowed for more favorable growing conditions and higher nutrient availability. This study indicates that gasifier-produced biochar has significant potential for use as a soil amendment in the humid tropics. However, further research
A thesis submitted in partial fulfillment of the requirements for the award of the Masters of Science Degree in Renewable Energy of Makerere University.
2009-05-01T00:00:00Z