Research Publications (Engineering and Built Environment)

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Analysis of temperature and rainfall trends in Vaal-Harts irrigation scheme, South Africa
(AJER, 2014) Adeyemo, Josiah; Otieno, Fredrick Alfred O.; Ojo, Olumuyiwa I.
Abstract: - Agriculture is crucially dependent on the timely availability of adequate amount of water and a conducive climate. Temperature and rainfall patterns impact the availability of water for agricultural uses. Therefore, temperature and rainfall are twin important environmental factors in agricultural activities such as tillage, planting, irrigation and mechanization. The characteristics of the Vaal-Harts temperature data for year 1996 to 2010 and rainfall data for year 1983 to 2010 were examined in this study using statistical techniques. Basic statistical properties of the data were determined using the mean, variance, coefficient of variation and Pearson’s correlation coefficient. Temperature and rainfall observations with the average of about 17.44 were used. The minimum and maximum temperatures recorded were 9.720C and 23.520C. The Coefficient of variation (CV) was found to be about 29.59. Variance is a measure of how far a set of numbers is spread out; and the variance of this set of observations is 26.625. The average yearly temperature increases insignificantly by a constant of about 0.117 (p = 0.163; 95% CI: -0.054 – 0.288), while rainfall shows decreasing trend annually which means that the dry season will be drier. The involvement of non-zero values in the serial correlation indicated the significance of the deterministic component in the data. The results of this analysis enhance our understanding of the characteristics of air temperature and rainfall in the study area for effective planning of farming operations.
Application of mine tailings sand as construction material : a review
(EDP Sciences, 2022) Ikotun, Jacob; Adeyeye, Rhoda; Otieno, Mike
Tailings are found during the exploration and processing of mineral ores. They contain a mixture of grounded rocks, processed effluent, and some trace elements that have the potential to damage the environment. Recent urbanisation has led to a large stockpile of tailings in many mining environment constituting health hazard. It becomes very important to develop disposal techniques that will reduce the huge mountain of tailings in mining environment. One of such method is the application of tailings in sustainable concrete production. It is shown that physical and chemical characteristics of tailings are comparable to crusher sand used in engineering construction and therefore, tailings can be used to partially replace sand in bituminous and concrete mixtures. In this review, specific interest has been given to iron, copper, and gold tailings, this is due to their dominance in mining areas of Kwa-Zulu Natal province of South Africa.
Application of organic coagulants in water and wastewater treatment
(IntechOpen, 2019-04-03) Tetteh, Emmanuel Kweinor; Rathilal, Sudesh
Coagulation is an essential mechanism that occurs in most conventional water and wastewater treatment plants. This occurs in a physical purification unit involving transport processes and the addition of coagulants for chemical reactions, charge neutralization, and formation of smaller flocs to agglomerate into larger flocs. This enhances the effective removal of recalcitrant contaminants by downstream processes. However, poor treatment of wastewater might have a high negative impact on biodiversity and the environment in general. This chapter seeks to address the limitation of employing inorganic coagulants by evaluating the efficiency of organic coagulants and exploring the factors and mechanism governing coagulation in a physiochemical treatment process of water and wastewater resources. The effect of pH, coagulant type and dosage to ease the high sludge production and discharge of residual metals into the downstream waters is addressed. The emerging of organic coagulants and technology to mitigate the performance and recovery of mineral coagulants from wastewater treatment residual is been proposed.
Comparative analysis and case study to evaluate conventional designs and environmentally sensitive infrastructure design solutions
(SAICE, 2016-08) Saroop, Shian Hemraj; Allopi, Dhiren
Globally the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming and other negative consequences. In the area of sustainability there is an urgent need to apply technologies and methods which deliver more sustainable performance in a way that is cost-effective. Sustainable, adaptive and mitigating approaches to climate change in the design of infrastructure are therefore important steering elements (FIDIC 2009)
Creating eco efficient township infrastructure projects with the use of green engineering solutions and sustainability criteria
(Institute of Municipal Enginering of South Africa, 2015) Saroop, Shian Hemraj; Allopi, Dhiren
Globally, the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming, and other negative consequences (Harvey and Wayne, 20084). As we face significant planetary issues such as global warming, it is clear that the engineering profession has a significant part to play in affecting the future of our planet. In order to stay competitive and to meet upcoming stricter environmental regulations and customer requirements, designers have a key role in designing civil infrastructure so that it is environmentally sustainable. These and other factors have compelled the engineer to design with greater care and in more detail. The changing roles of engineers will be highlighted, in order to react to changes in climate. Mainstreaming environmental aspects and incorporating the eco-efficiency concept into various stages of infrastructure development have not been considered as much as they should have been. Engineers need to look at greener technologies rather than just using traditional engineering solutions. This paper looks at the effects of climate change on infrastructure and the changing role of engineers. It aims to demonstrate the use of sustainability criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper focuses on the concept of eco-efficiency in infrastructure design that promotes the use of the greener engineering options, enabling him/her to choose the one likely to yield the best performance with the least environmental impact. It looks at a number of recommended green practices on infrastructure services design, that are environmentally sound placing, fewer burdens on the environment.
Green roofs and stormwater runoff quality in the urban landscape in South Africa
(National Research Council Canada, 2021-06-20) Sucheran, Arisha; Sucheran, Reshma
A number of sustainable urban drainage systems (SuDS), such as green roofs, are being developed and implemented in cities around the world to help reduce stormwater runoff and improve stormwater runoff quality. This study compares the water quality of green roofs with that of conventional roofs in the eThekwini region, South Africa. Samples of stormwater runoff from the different green roof systems on the eThekwini Green Roof Pilot Project were collected to test their level of contaminants and pollutants. The tests focused on all physical, aesthetic, chemical, and microbiological determinants pertaining to stormwater runoff. For all tests, the level of contaminants and pollutants were measured against the South African Water Quality Guidelines Volume 7 for Aquatic Ecosystems. The data revealed significant variations in pollutant concentrations between the green roofs and the conventional roof. Moreover, runoff water quality varied across the various roof types, which may indicate that the substrate composition has the greatest impact on green roof performance regarding rainwater quality. Overall, the results suggest that these green roof systems do not have the ability to filter pollutants out of stormwater runoff, but rather increase their levels of concentration.
The use of eco efficient criteria in the design of infrastructure projects
(WITPRESS, 2016) Saroop, Shian Hemraj; Allopi, Dhiren
Globally, the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming and other negative consequences. In the area of sustainability, there is an urgent need to apply technologies and methods that deliver better and more sustainable perfor-mance in a way that is cost-effective. Sustainability, adaptive and mitigative approaches to climate change, in the design of infrastructure, are therefore important steering elements [1]. A systematic and iterative analysis of the environmental impact of various design solutions is commonly suggested for infrastructure projects, but rarely happens. The lack of appropriate tools and skills for sustain-able design was often quoted as a barrier to sustainable design [2]. To stay competitive and to meet upcoming stricter environmental regulations and customer requirements, designers have a key role in designing civil infrastructure so that it is environmentally sustainable. These and other factors have compelled the engineer to design with greater care and in more detail. The changing roles of engineers will be highlighted, to react to changes in climate. This paper aims to demonstrate the importance of eco efficient criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper also gives an overview of the proposed Green Township Infrastructure Design toolkit and promotes the use of green practices on infrastructure services design that is environmentally sound, placing fewer burdens on the environment.
Water quality modelling and quantitative microbial risk assessment for uMsunduzi River in South Africa
(IWA Publishing, 2022-04) Ngubane, Zesizwe; Bergion, Viktor; Dzwairo, Bloodless; Troell, Karin; Amoah, Isaac Dennis; Stenstrom, Thor Axel; Sokolova, Ekaterina
South African rivers generally receive waste from inadequate wastewater infrastructure, mines, and farming activities, among others. The uMsunduzi River in KwaZulu-Natal, South Africa, is among these recipients with recorded poor to very poor water quality. To identify parts of the uMsunduzi River that are polluted by Cryptosporidium and Escherichia coli (E. coli), this study mapped out pollutants emanating from point and non-point sources using the Soil and Water Assessment Tool (SWAT). Streamflow calibration in the upper and lower reaches of the catchment showed good performance with R² of 0.64 and 0.58, respectively. SWAT water quality output data were combined with a Quantitative Microbial Risk Assessment (QMRA) to understand the microbial health implications for people using river water for drinking, recreational swimming, and non-competitive canoeing. QMRA results for Cryptosporidium and pathogenic E. coli showed that the probability of infection for most users exceeds the acceptable level for drinking and recreation as outlined in the South African water quality guidelines, and by the World Health Organization (WHO). The results of this study can be used as a baseline to assess the economic and health implications of different management plans, resulting in better-informed, cost-effective, and impactful decision-making.