Faculty of Engineering, Technology, Applied Design & FineArt (FETADFA)

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Open Access
Stochastic Modeling of Internet Service for Profit Optimization in Uganda
(IST-Africa, 2018) Christopher, Senfuka; Paul, Kizito Mubiru; Maureen, N. Ssempijja
We consider an internet cafe faced with an optimal choice of bandwidth for internet users under stochastic stationary demand. The choice is made over uniformly time horizons with a goal of optimizing profits. Considering customer demand, price and operating costs of internet service, we formulate a finite state Markov decision process model where states of a Markov chain represent possible states of demand for internet service. A profit matrix is generated; representing the long run measure of performance for the Markov decision process problem. The problem is to determine an optimal bandwidth adjustment policy so that the long run profits are maximized for a given state of demand. The bandwidth adjustment policies are determined using dynamic programming over a finite period planning horizon. Results from a case study demonstrate the existence of an optimal statedependent option for bandwidth adjustment and profits in providing internet service.
Open Access
Modeling Campaign Optimization Strategies in Political Elections under Uncertainty
(International Journal of Scientific Research in Mechanical and Materials Engineering, 2018) Christopher, Senfuka; Paul, Kizito Mubiru; Maureen, N. Ssempijja
In most political campaigns,the overall goal of every candidate is to maximize the number of voters during the election exercise.In such an effort,cost effective methods in choosing the optimal campaign strategy areparamount.In this paper, a mathematical model is proposed that optimize campaign strategies of a political candidate.Considering uncertainty in voter support and cost implications in holding political rallies,we formulate a finite state markov decision process model where states of a markov chain represent possible states of support among voters.Using daily equal intervals,thecandidates‟s decision of whether or not to campaign and hold a political rally at a given location were made using discrete time Markov chains and dynamic programming over a finite period planning horizon.Empirical data was collected from two locations on a daily basis during the campaign exercise.The data collected was analyzed and tested to establish the optimal campaign strategy and costs at the respective locations.Results from the study indicated the existence of an optimal state-dependent campaign strategy and costs at the respective political rally locations.
Open Access
Extending measurement range for three-dimensional structured light imaging with digital exponential fringe pattern
(The 2nd Annual Higher Education Conference, Hotel Africana Kampala, Uganda, 2020) Abel, Kamagara
In this paper, a method and an approach for intrinsically extending the measurement range for digital fringe projection profilometry with structured light imaging techniques is presented. This approach exploits the fact that at low levels of defocusing, exponential binary-coded fringe pattern exhibits a quasi-sinusoidal form having intact binary structures with reduced or negligible errors owing to high-order harmonic robustness during fringe generation. Experimental simulations and results show that within the desired region of defocus or at an extended measurement range, the proposed method exhibits a 45% comparative reduction in root-mean-square phase error hence improvement in final measurement result.
Open Access
Effect of Boron Content on Strain-Hardening Exponent in Recycled Steel
(International Journal of Academic Engineering Research, 2020) Christopher, Senfuka; Paul, Kizito
While the elastic zone in the deformation process of materials is mainly represented by a linear function of gradient E, the plastic portion has been characterized by various exponential functions with an exponent n that varies with its chemical composition, the level of work hardening and the material in question among others. Recycled steel, whose composition depends on the source and availability of its raw material, has an extremely vulnerable n-value. In this paper, the effect of the boron content in recycled steel on the n-value of thermo-mechanically treated bars made from it has been studied. To do this, TMT bars were subjected to tensile testing and the corresponding force extension diagrams plotted. The values of εi10 and εi20 for the interval between 10% and 20% deformation respectively were determined to correspond to the stress values σi10 and σi20 so that was calculated as the ruling n-value for each interval. Spectro-analysis was used to determine the chemical composition of the samples so that the percentage boron content by weight was plotted against the n-value. The growth of the n-value with boron content has been shown to obey a polynomial function and to enhance the tendency to strain-hardening, implying early onset of failure in pronounced cold deformation.
Open Access
Analysis of Leaching Rate of Heavy Metals from Fly Ash at Varying Leachant pH & Cumulative Liquid to Solid Ratios
(i-manager’s Journal on Material Science, 2020) Tobby, Micheal Agwe; Sharma, S. N.; Pandey, Govind
Fly ash (FA) is a particulate matter consisting of finely divided, non-combustible particles obtained from the flue gases arising from combustion of coal, accounts for over 80% of the total ash produced during coal combustion. In 2018 alone, about 780 million tons of FA has been generated globally, of which voluminous quantity remained unutilized, hence dumped into the environment. This continued disposal of FA into the environment makes the heavy metals contained therein to move out in the leachate generated, polluting the soil, surface and ground water sources among others. In this study, 5 sets of leaching test columns were packed with an equal quantity of air dried fly ash samples and each of them leached with leachant of pH 5.87, 6.08, 6.41, 6.46 and 7.01 and eluate from each column collected at cumulative liquid to solid (L/S) ratios in l/kg of 0.1, 0.2, 0.5, 1.0 and 2.0. Analysis of the eluate for Copper (Cu), Selenium (Se), Zinc (Zn), Cadmium (Cd), Lead (Pb), Nickel (Ni), Chromium (Cr) and Arsenic (As), revealed that the concentrations of Se at Selenium L/S of 0.1 for leachant pH of 5.87, 6.41 and 7.01, exceeded the allowable limits for non-hazardous wastes disposal into the landfills.
Open Access
Effective Application of 4th Industrial Revolution Technologies During Engineering Research and Teaching in Ugandan Universities
(The 2nd Annual Higher Education Conference, Hotel Africana Kampala, Uganda, 2020) Isaac, Ndawula; Dianah, Asiimwe; Samuel, S. Mushakangoma; Pascal Musaazi, Senkindu
The 4th Industrial Revolution (4IR) technologies is the recent research topic of interest among the academicians, since the 4IR technologies make up the latest era of digitization. The 4IR technologies demands changes in the three fundamental functions (teaching, research and community service) of higher institutions of learning. Each revolution technologies needs different job skills and competences, the 4IR technologies will also require new job skills and competences from the university graduates particularly in the field of engineering. The teaching staff at universities shall play an important role in imparting the necessary job skills and competences to graduates. Recently several research on 4IR technologies in higher institutions of learning has been presented, but none is addressing the issue of availability of effective utilization of 4IR technologies in engineering education. So, this paper presents the investigation of the availability of effective application of 4IR technologies during university engineering research and teaching in Ugandan universities. The paper also examined the behavior, knowledge, and perception of teaching staff towards 4IR technologies in the university engineering education in Uganda. 256 respondents were interviewed using online questionnaire and data collected was analyzed using MATLAB program. The findings disclose that there is low degree of application of 4IR technologies by teaching staff in engineering sector during teaching and research in the seven universities in Uganda.
Open Access
Assessment on Power Distribution Network Planning in sub-Saharan Africa
(IEEE, 2021) Michael, E. Irechukwu; Michael, N. Irechukwu; Samuel, S. Mushakangoma
Power system distribution network planning (PSDNP) encompasses several tasks including ensuring sufficient substation capacity and distribution capacity for the end users. Both rural communities and urban dwellers benefit when there is a well-planned distribution network. City power consumers enjoy stable electricity supply and the number of annually connected rural households increases with an efficient planning scheme in place. However, this is not the case in many cities and rural areas in sub-Saharan Africa. Poor distribution network planning by many power utilities has led to the annual energy demand growing at a much higher rate than the number of electrified households in many sub-Saharan African countries. Therefore, this paper discusses challenges faced by power utilities and energy consumers due to poor distribution planning techniques. This paper proposes an implementation plan to address the inefficient planning challenges faced by the rural communities and urban dwellers. After that, a case study is selected in East Africa, and the solutions are applied.
Open Access
A Regression Model to Enhance the Profitability of Local Construction Contractors in Uganda
(Journal of Construction in Developing Countries, 2021-08-23) Buhamizo, Isaac; Muhwezi, Lawrence; Sengonzi, Ruth
Doubtlessly, the primary goal of every construction company is to maximise profitability. Without this, construction companies cannot survive. Incidentally, Ugandan local construction contractors (LCCs) continue to collapse in a short period, despite enormous public and private investments in the construction sector. This study investigates the profitability of LCCs in Uganda. An investigation was conducted to develop a regression model that would enable LCCs to enhance their profitability and minimise business failure. A questionnaire survey was conducted to collect primary data from 47 local construction companies registered with the Uganda National Association of Building and Civil Engineering Contractors (UNABCEC) and secondary data were collected from audited books of accounts covering from year 2016 to 2018. Thirty-five valid responses were received, representing a response rate of 74%. Data were coded into SPSS version 25, analysed and displayed using the relative importance index (RII), statistical correlation and regression analysis. The findings indicated that the profitability of LCCs was unsatisfactory when compared to the profitability ratios recommended for the construction industry and those of contractors in other countries. The results also indicate that the profitability of LCCs is significantly affected by the timeliness of payments, cost of f inance, competitive bidding environment, project delays, price fluctuations and corruption tendencies, in that order. The findings of this study will benefit construction industry players by providing awareness about the factors affecting the profitability of LCCs. A regression model to enhance profitability was developed using regression analysis. This will help LCCs enhance their profitability by developing mitigation strategies that prevent low profitability; consequently, business failure will be minimised.
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022) Tobby Michael, Agwe; Philip, Tibenderana; Moses N., Twesigye-Omwe; Joel, Webster Mbujje; Sholagberu Taofeeq, Abdulkadir
A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is fit for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water unselected properties of reinforced concrete and its durability, thus, further research is recommended
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022) Tobby Michael, Agwe; Philip, Tibenderana; Moses N, Twesigye-Omwe; Joel Webster, Mbujje; Abdulkadir, Sholagberu Taofeeq
A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is fit for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water on selected properties of reinforced concrete and its durability, thus, further research is recommended.
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022-12-10) Tobby Michael, Agwe; Tibenderana, Philip; Twesigye-Omwe, Moses N; Abdulkadir, Sholagberu Taofeeq
properly cited. A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast-depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is ft for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water on selected properties of reinforced concrete and its durability, thus, further research is recommended.
Open Access
Clean Eco-Friendly Cooking Energy as Sustainable Approach and Mitigation to Climate Change: A Case Study of Ankole, Western Uganda.
(Kabale University, 2023) Kayamba, William Kariiti
The study investigates how communities in the Ankole region, western Uganda are coping with a shortage of cooking fuels, climate change and what strategies they have set up to counteract its effects using innovative, sustainable, renewable and affordable technological methods. The objectives of the study are: 1) to investigate the type of cookstoves used in cooking that is being used in the area under study. 2) To suggest eco-friendly cook stoves that can be used for cooking to save the environment and reduce health hazards that are related to inhalation of smoke. It was carried out in the districts of Mbarara and Bushenyi which are diverse in their setting. The main objective was to investigate how traditional cooking fuels have become a health hazard to many mothers and children in Ankole, human activities and rural-urban migration, have caused hiking of prices for fuel for cooking; wetland drainage, bush clearing for farming, charcoal burning, brick making associated with social and economic developments have affected the environment. Traditional methods of cooking still dominate in Ankole, where three stones are still used. Charcoal has become a major fuel for cooking in many homes as an alternative to firewood, in addition to briquettes, biogas, LPG and volcanic rocks. A sustainable eco-friendly stove is proposed to mitigate environmental degradation.
Open Access
Clean eco-friendly cooking energy as sustainable approach and mitigation to climate change: A case study of Ankole, Western Uganda
(Kabale University, 2023-02-07) Kayamba William Kariiti
The study investigates how communities in the Ankole region, western Uganda are coping with a shortage of cooking fuels, climate change and what strategies they have set up to counteract its effects using innovative, sustainable, renewable and affordable technological methods. The objectives of the study are: 1) to investigate the type of cookstoves used in cooking that is being used in the area under study. 2) To suggest eco-friendly cook stoves that can be used for cooking to save the environment and reduce health hazards that are related to inhalation of smoke. It was carried out in the districts of Mbarara and Bushenyi which are diverse in their setting. The main objective was to investigate how traditional cooking fuels have become a health hazard to many mothers and children in Ankole, human activities and rural-urban migration, have caused hiking of prices for fuel for cooking; wetland drainage, bush clearing for farming, charcoal burning, brick making associated with social and economic developments have affected the environment. Traditional methods of cooking still dominate in Ankole, where three stones are still used. Charcoal has become a major fuel for cooking in many homes as an alternative to firewood, in addition to briquettes, biogas, LPG and volcanic rocks. A sustainable eco-friendly stove is proposed to mitigate environmental degradation.
Open Access
The Development Related Role of Pottery Production in the Ankole Region in Western Uganda: A Case Study
(Bp International, 2023-02-08) Kayamba, William K.; Kwesiga, Philip
The main aim was to look at how the pottery business contributes to reducing poverty and unemployment as well as how it affects the environment. The study looked into the socioeconomic and technical aspects of pottery manufacture in the Ankole district of western Uganda. Both qualitative and quantitative techniques of data gathering and analysis were used throughout the study's fieldwork. First, 148 respondents were given questionnaires from a diverse cross section of the Ankole district. Second, in order to get a more thorough grasp of the experiences and viewpoints of both traditional and modern potters— something a questionnaire alone could not provide—40 potters were interviewed and seven focus group talks were held with potters from this region. According to the results, women are predominantly responsible for creating traditional pottery, whereas males are mostly involved in developing new techniques and manufacturing commercial pottery. Unquestionably, brick and tile manufacturing has developed into a successful industry, particularly for male adolescents because to the great demand for the goods from both rural and urban populations. However, pottery-related activities have wreaked havoc on the ecosystem. These efforts have produced pools of still water in some locations, which serve as breeding grounds for mosquitoes that carry malaria over much of the region.
Open Access
Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating.
(Kabale University, 2024) Rwabona, Katashaya Steven
In this article, we present a method to determine the bandgap of a thermochromic phosphor film by simple reflectance measurements under controlled heating. The phosphor is illuminated by a light-emitting diode while being heated continuously. The reflected light is detected using a calibrated photodiode circuit based on an operational transconductance amplifier. We apply the Schuster- Kubelka-Munk function to deduce the absorbance over temperature and thus the bandgap. We show, for the first time, that the thermochromic phosphor's colour change follows Arrhenius's Law and therefore involves activation energy. We estimate the bandgap to be between 1.1 eV and 1.9 eV and find an activation energy of 46.67 ±1.6 kJ/mol. The simplicity of the approach will appeal to undergraduate teachers and students of physics and materials science. The technique can be used to investigate other thermochromic materials as well.
Open Access
A new combined analytical–numerical probabilistic method for assessing the impact of DERs on the voltage stability of bulk power systems
(Energy reports, 2024) Wanjoli, Paul; Moustafa, Mohamed M. Zakaria; Abbasy, Nabil H.
The integration of distributed energy resources (DERs) and unpredictable loads has increased uncertainty in power systems. Traditional methods struggle to assess performance under these uncertainties, and existing probabilistic methods face challenges with complexity and accuracy. This paper introduces a new combined analytical–numerical probabilistic method to assess the impact of DERs on voltage stability. Using Bayesian Parameter Estimation (BPE), the method derives the analytical properties of random variables (RVs) associated with DERs and loads, obtaining posterior distributions. The Metropolis–Hastings sampling technique then estimates these posteriors numerically, enabling accurate predictions of DERs and load outputs. Voltage stability analysis was performed using the continuation power flow method and validated on the IEEE 59- bus test system in MATLAB/Simulink. The results show that integrating DERs significantly improves voltage stability. The proposed method outperforms the Monte Carlo simulation (MCS)-based method in accuracy and computational speed, increasing DERs penetration and voltage stability limits by 3%. It closely matches MCS voltage estimates but requires fewer iterations (500 per loading increment) compared to MCS’s 1000, leading to faster computation times (a few hours to one day versus up to three days for MCS). This method provides an efficient solution for managing uncertainties in power systems.
Open Access
A state-of-the-art review on the modeling and probabilistic approaches to analysis of power systems integrated with distributed energy resources.
(Ain Shams Engineering Journal, 2024) Wanjoli, Paul; Abbasya, Nabil H.; Moustafa, Mohamed M. Zakaria
Modern power systems are shifting toward decarbonization and incorporation of distributed energy resources (DERs) to replace fossil fuel generators. Although promising, DERs introduce uncertainty because of their intermittent nature. This study provides a comprehensive survey of current approaches for modeling system uncertainties and methods of analysis, particularly in the context of static voltage stability studies within modern power systems. Emphasis is placed on evaluating various models applied to different system random variables (RVs), focusing on their suitability for those particular RVs. Additionally, the study examines the characteristics and frameworks of prominent probabilistic methods (PM), evaluates their efficacy, and discusses static voltage stability analysis approaches, emphasizing solution structures and appropriate applications. It concludes by thoroughly reviewing both numerical and analytical PM methods and offering insights into their strengths and limitations. The provided comprehensive survey reveals that, considering system uncertainties, voltage stability studies have gained the most share, followed by small-signal stability studies, whereas the frequency stability studies have gained the least share.
Open Access
Investigating the cost of mechanized unpaved road maintenance operations in Uganda
(Elsevier Ltd., 2024) Obeti, Andrew Moses; Byaruhanga, Chris Bic; Muhwezi, Lawrence; Kakitahi, John Muhumuza
Force Account Mechanism (FAM) is the predominant road maintenance system in Uganda’s local government setup and a similar, though slightly different approach, is used in some large private sector agriculture planta tions. With the Uganda Road Fund (URF) 2021/2022 annual report and previous research citing challenges in cost management and efficiency of the FAM method of road maintenance, it becomes paramount to analyse how FAM is implemented in government-led operations, in comparison to similar private sector approaches, while proposing possible solutions to these challenges. This research offered to analyse unpaved road maintenance cost drivers alongside providing a cost model solution to improve on cost prediction of the FAM system. Gulu District Local Government (DLG) and Kakira Sugar Limited (KSL) were selected as case study areas. Two descriptive research methods were used: observations and case study approach. The selected case study areas were accessible and reachable in terms of data. Control parameters affecting unpaved mechanized road maintenance were identified as machine repair costs, tool costs, labour costs, material costs, fuel costs and machine fuel costs. Unpaved mechanized road maintenance costs at KSL and Gulu DLG were computed as a cost/km ratio of 26,442,032Ugx/km (6,958.4USD/km) and 32,674,895Ugx/km (8,598.65USD/km) respectively. The Uganda National Roads Authority (UNRA) unpaved road maintenance costs were calculated as an average of 34,987,122.9Ugx/km (9,165USD/km) while the World Bank ROCKS database provided a comparable figure of 7,971USD/km (30,553,440.83Ugx/km). A USD to Ugx conversion rate of 3,800 was used. Two linear regression cost models with a 0.679 and 0.687 R 2 value were computed, and these can be used in preliminary road maintenance cost prediction. The study recommends the need for an effective, digital road maintenance cost database system for mechanized unpaved road maintenance works, cost driver analytics and management, alongside improvement in aspects of maintenance processes at both the DLG and KSL. Further research can be conducted on equipment condition level prediction and analytics in the private sector and at the DLG.
Open Access
Analyses of Bioretention Systems for Removal of Stormwater Pollutants
(Journal of Ecological Engineering, 2024) Sholagberu, Abdulkadir T.; Nuwagaba, Emmanuel; Tibenderana, Philip; Terseer, Ako; Bainomugisha, Jonan; Twesigye-omwe, Moses N.; Agwe, M. Tobby; Oluwatosin, Olofintoye O.
Stormwater transports directly into rivers eroded soil, animal wastes, pesticides, fertilizers and other potential pollutants. Bioretention is often designed to capture and treat it using the natural properties of soil and plants. However, selection of appropriate media structure and plants need to be adequately studied. This study investigated the performance of bioretention system in removing stormwater pollutants using Dracaena, a local plant, also called Song of India Plants. Physical model of three Columns A, B and C were developed having five layered filter media of different configurations whose materials were analyzed to meet the design standards. The plants were introduced into Columns A and C leaving out B as control experiment. The quality parameters were determined before and after treatments at ages 10, 20, 30and 40 days when Dracaena plants were introduced into bioretention models. The results showed that the bioretention model drastically improved stormwater quality by reducing values of electrical conductivity, total coliforms (TC), fecal coliforms (FC), total suspended solids (TSS) and biochemical oxygen demand (BOD) as compared to the tested raw stormwater samples. The filter media in both Columns A and C substantially reduced the pollutant levels to standard discharge limits for all parameters tested such as TSS, TC, FC, BOD and nitrates. BOD fell within the recommended standard after 20 days of treatment in Column C with considerable reduction in TC and FC by 68.9% and 75.4% respectively when compared to raw stormwater sample. However, Column C completely removed TC and FC at 40 days which are pathogen indicators in wastewater. This study would be useful to the stakeholders for sustainable stormwater treatment and management.
Open Access
Performance evaluation of lime improved lateritic soil with the addition of pulverised snail shell and sawdust ash for sustainable highway infrastructure
(Discover Civil Engineering, 2024-02-03) Fadugba, Olaolu George; Ojo, Adeyemi Amos; Oluyemi Ayibiowu, Bamitale Dorcas; Omomomi, Oladapo Jayejeje; Bodunrin, Michael
This research investigated the effects of lime, Pulverized snail shell (PSS), and sawdust ash on the mechanical proper ties of lateritic soil for soil stabilization in construction. The use of this waste materials aligns with the United Nations’ Sustainable Development Goals (SDGs), particularly Goal 12 on responsible consumption and production and Goal 9 on sustainable infrastructure development. Reusing waste materials for soil stabilization supports a circular economy approach, diverting these materials from landfills and promoting their sustainable use as valuable resources. Various tests, including maximum dry density, moisture content, unconfined compressive strength (UCS), triaxial, permeability, compressibility, and California Bearing Ratio (CBR) tests, were conducted on soil samples with different proportions of additives. The results show that the addition of additives reduced maximum dry density and increased moisture content. The sample with 6% lime and 7.5% PSS exhibited the highest UCS of 302 kPa after 28 days of curing, while the untreated sample had a UCS of 121 kPa. Triaxial tests revealed reduced cohesion and increased angle of internal friction with higher additive content. The 6% lime and 7.5% PSS sample displayed the highest shear strength of 60.6 kPa and elastic modulus of 181.8 MPa. Permeability tests demonstrated that the 6% lime and 6% sawdust ash sample had the lowest permeability (6.67 × 10–7 m/s) among the stabilized samples. The untreated soil exhibited high compressibility, whereas the 6% lime and 7.5% PSS sample exhibited the highest resistance to compression and deformation. The untreated soil had a soaked CBR value of 8%, while the 6% lime and 7.5% PSS sample achieved the highest soaked CBR value of 38%, making it suitable as a sub-base material. These findings highlight the effectiveness of lime, PSS, and sawdust ash in enhancing the mechanical properties of lateritic soil and offer valuable insights for soil stabilization in construction of Sustainable Highway Infrastructure.