Doctoral Degrees (Civil Engineering)

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Browsing Doctoral Degrees (Civil Engineering) by Subject "Atmospheric temperature"

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    Stormwater runoff treatment from automobile workshops in Nigeria using combined rice husk, gravel and activated carbon filters.
    (Stellenbosch : Stellenbosch University, 2022-11) Ataguba, Clement Oguche; Brink, Isobel; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Stormwater runoff from automobile workshops is a major source of pollutant mass flow to rivers, which pose a risk to aquatic ecosystems. An investigation into pollution of stormwater runoff from selected automobile workshops, the development of low cost treatment technologies using granular activated carbon (GAC), rice husk (RH) and river gravel filters (GR) for removal of metals from polluted stormwater runoff from automobile workshops and the application of Langmuir and Freundlich isotherm models in predicting the removal of lead and iron were carried out. A comparative study using the low cost treatment technologies and conventional oil & grease trap (COT) in the removal of oil & grease was also done. Furthermore, a sustainability assessment of the low cost treatment technologies of GAC-RH and GR-GAC was included using a triple bottom line approach (economic, environmental and social impacts). These investigations indicated that stormwater runoff from automobile workshops was highly polluted with concentrations above the permissible discharge limits in Nigerian and American standards. Additionally, the developed low cost treatment technologies were found to lower the high concentrations of metals, indicating their potential successful use in the treatment of the stormwater runoff. This specifically with the GAC-RH filter material combination exhibiting high metals removal efficiencies when compared with GR-GAC and RH treatment filters. The research also indicated that the low cost treatment technologies compared favourably well with the COT in the removal of oil and grease (O&G). The order of oil and grease removal efficiencies of the treatment technologies was GAC-RH > RH > GR-GAC > COT. Langmuir isotherm model was found to predict the removal of lead and iron as favourable adsorption process while the Freundlich isotherm model predicted the removal of lead and iron as a chemisorption process. During adsorption testing, the adsorption capacity of the GAC-RH and GR-GAC filter material combinations decreased with increased dosages of the adsorbents. The overall sustainability assessment of the GAC-RH and GR-GAC technologies indicated that the GAC-RH filter showed a slightly higher overall sustainability score when compared to the GR-GAC filter application. Finally, a centralized auto-mechanic village was proposed for major towns and a hypothetical design for stormwater detention system was also presented in a proposed Design Guide for Stormwater Management: Application to Auto-Mechanic Villages in Nigeria.