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Impacts of process selection and process train in the design of water treatment plants in South AfricaNgcobo, S.E. January 2019 (has links)
Background
The South African Government is spending huge amounts of money (about R64 billion for the fiscal years 2015/16 to 2018/19 as per the revised strategic plan – vote 36) and more than R30 billion was targeted water infrastructure investments by the end of 2014/15 financial year (Ruiters & Matji, 2015) striving to provide all its citizens with access to good quality water services through its organs of state such as municipalities and water boards. A study of more than one hundred (100) waterworks carried out throughout the country in the early years of the 21st century by Chilton and Polasek (2013) revealed that none of them was found to be appropriately designed in terms of the processes installed.
The author of this dissertation aims to bridge the gap in Chilton and Polasek’s (2013) study of more than a hundred (100) waterworks, in which they did not quantify the actual impacts caused by the design flaws they identified. The present study was carried out on four waterworks situated in two provinces, namely Gauteng and North West. The aim was to quantify the financial implications, operations and maintenance complications/difficulties.
The four methods used to carry out this study are: Initial design catering for the ultimate plant capacity; design conforming to surface water treatment regime; actual operational performances of plants; and financial implications for the clients of the case study plants selected.
The approach was to compare the design against the recommended and well documented treatment regime applicable to surface water, selection of processes, design and installation using the four methods mentioned above. All the water treatment plants selected as case studies for this report have several inherent design deficiencies which negatively affect the ability to produce good quality potable water, and to promote and facilitate water services delivery most cost effectively in a sustainable manner. Inherent design deficiencies confirmed in the four case study plants include failure to cater for the ultimate design capacities; failure to utilise the value engineering tools in the design; poor selection of processes and their arrangement and negative financial Implications for the owners of these waterworks.
The report recommends formation of a Water Treatment Design Committee (WDC) or a National Water Agency of South Africa (NWASA) responsible for water capital projects implementation.
Keywords: conventional, water treatment, process, South African Government, waterworks, guidelines, capital project, consultant, engineer, and services delivery. / Dissertation (MSc (Water Utilisation Applied Science))--University of Pretoria, 2019. / Chemical Engineering / MSc (Water Utilisation Applied Science) / Unrestricted
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Pathway Analysis for Biocrystallisation and Biodeposition of Pd(II) and Pt(II) Metals by Sulfate-Reducing BacteriaMalunga, Khanyisile Bridgete January 2021 (has links)
Despite limited availability of platinum group metals such as palladium and platinum, there is an increasing demand to use them especially as catalysts for fossil fuel free energy sources, such as electric cars and hydrogen fuel cells. Despite this increase in demand, conventional recovery of these metals from wastewater and solid waste streams is still not practiced, and the release of large amounts of metals tends to upset the delicate balance of biodiversity in sensitive ecosystems. Therefore, with the effect of climate change being apparent research focus has shifted to non-carbon energy systems such as biotechnology. Microbial recovery of platinum group metals is emerging as a clean alternative bioremediation processes as compared to the traditional physical and chemical recovery processes, and Sulfate-Reducing Bacteria have drawn a great deal of attention because they have proven to have excellent metal reaction properties for platinum group metals such as palladium and platinum. However, to effectively reduce palladium and platinum to their elemental form a clear understanding of the following is needed; the particle physics, how the organisms interact with the metals under certain environmental conditions as well as the limitations posed by the metal’s occurrence in chelated states on the adsorption and uptake by living organisms. Therefore, the aim of the study was to investigate the use of Sulfate-Reducing Bacteria and Desulfovibrio desulfuricans DSM642 in the bioreduction, biodeposition and biocrystallisation of palladium and platinum. Sulfate-Reducing Bacteria were isolated from sludge from a wastewater treatment plant in the North west, South Africa, and Desulfovibrio desulfuricans DSM642 was purchased from Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) in Germany. Batch experiments were conducted at different palladium and platinum concentrations from 356.3 mg/L to 1928 mg/L for palladium and 20 mg/L to 140 mg/L for platinum. The experiments were conducted at an optimum pH of 4, a temperature of 30°C under 120 rpm shaking under in a dark room under oxygen free nitrogen to achieve anaerobic conditions. After cell preparation, cells were harvested and challenged with different concentrations of Pd(NH3)4Cl2 and Platinum Standard solution. Removal of the metals by the cells happened at the expanse of formate as an electron donor for 6 and 7 hours for palladium and platinum respectively. After incubation a maximum of 96 % and 99 % of palladium was removed and a maximum of 59% and 56% of platinum was removed by Sulfate-Reducing Bacteria and Desulfovibrio desulfuricans respectively. TEM analysis revealed black oblique deposits on the cell wall of both treatments, which revealed the biomineralisation processes happened on the cell membrane. Palladium deposits were confirmed by X-Ray Diffraction (XRD) to be elemental palladium nanoparticles with a maximum crystal size of 16.9 nm, confirming bioreduction and statistical analysis of the data proved that both treatments have the potential to bioremediate palladium and platinum contaminated environments. / Dissertation (MSc ((Applied Science) (Water Utilisation)))--University of Pretoria, 2021. / Chemical Engineering / MSc ((Applied Science) (Water Utilisation)) / Unrestricted
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Critical Transmission Sectors of Energy-Water-GHG Nexus / Critical Transmission Sectors of Energy-Water-GHG NexusWang, Xuechao January 2020 (has links)
Využití vody, spotřeba energie a emise skleníkových plynů (GHG) jsou rozhodujícími ukazateli a do značné míry souvisí s udržováním nebo dosahováním environmentální a sociální udržitelnosti. Tato práce prezentuje vyvinuté metodiky. Představuje také provedené případové studie, které prozkoumaly a identifikovaly Water-Energy-GHG Nexus (WEGN) z pohledu dodavatelského řetězce. Pro analýzu a návrh sítě WEGN jsou navrženy tři metodiky, které jsou založeny na nové aplikaci a integraci modelu vstup-výstup (IO), geografického informačního systému (GIS) a sítě dodavatelského řetězce (SCN), a zároveň řeší výzvy, které dříve neumožňovali praktické implementace. Použitelnost těchto metod je prokázána třemi komplexními případovými studiemi zaměřenými na odvětvovou environmentální účinnost, regionální environmentální účinnost a kritické přenosy WEGN. Mezi mé příspěvky v této oblasti patří: i. Nový nástroj pro hodnocení založený na IO pro identifikaci regionální environmentální účinnosti z hlediska WEGN, zejména pro regiony, které jsou úzce propojenyobchodem. ii. Pokročilá integrace metodik GIS a IO (GIS-IO) za účelem odhalení a mapování sítě WEGN, sledování kritických meziregionálních a sektorových toků WEGN, vyjasnění regionálních, odvětvových a celosvětových vzorců sítě WEGN a určení souvisejících výhod pro různé regiony. iii. Efektivní metoda hodnocení založená na IO a SCN pro kvantifikaci sektorových koeficientů WEGN. Navrhované metodiky, s podporou sady komplexních základních rovnic, transformují komplikované výzvy identifikace a analýzy sítě WEGN do snadno srozumitelného formátu, z čehož vznikají robustní řešení pro zlepšení posuzování environmentální udržitelnosti a zmírnění environmentálních tlaků. Například v jedné z případových studií ukazují výsledky nového přístupu GIS-IO zjevné rozdíly mezi různými zeměmi v rámci EU27, mezi různými sektory a také pokud srovnáme EU27 jako blok zemí, s ostatními státy světa. Analýza ukázala, že země EU27 přispěly o 1.4 Gt nižšími emisemi CO2, o 64.5 Gm3 menší spotřebou vody a 4.9 × 104 PJ nižší spotřebou energie ve srovnání se zbytkem světa, přičemž generovaly ekvivalentní ekonomickou produkci. To má dramatický dopad na globální prostředí. Největší úspěch v CWE mezi zeměmi EU27 měly Německo, Francie a Itálie. Práce doporučuje, aby EU27 poskytovala více technické podpory zemím, které těchto výsledků nedosahují, aby se zvýšila účinnost využívání zdrojů.
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Towards efficient water utilisation in South African Higher Education Institutions: A case study of University of VendaNkuna, Zanele 18 May 2019 (has links)
MESHWR / Department of Hydrology and Water Resources / Water scarcity has become a constraint for sustainable development in the higher education institutions in South Africa including University of Venda. Water infrastructure is one of the major challenges within higher education institutions, the existing water supply infrastructure is over 20 years old and was not planned for the current population. This study aimed at developing a water management plan for higher education institutions in South Africa using the University of Venda as a case study. A water resource management plan provides a road map for reducing water consumption while encouraging sustainable water utilisation. Evaluation was done within the institution to identify water sources, water resources infrastructure and water utilisation. The study employed questionnaire survey to collect data on water consumption, to evaluate issues of the institutional participation in resolving the water problems within the institution and deduce water wastage.
Water supply data was obtained from meter readings and water invoices obtained from Vhembe District Municipality and University of Venda. The latter were used to determine water consumption within the institution. Based on the sample size, the results indicated the estimated amount of water consumed daily by UNIVEN population is 66 341.9 l/d excluding water utilised at the cafeteria, car wash and auditorium. The average water supplied to UNIVEN in 2017 was 67 642. 25 mega litres/month, this indicates that more water is supplied to the institution since the estimated institutional water demand excluding illegal students in the residence halls ranged between 415 740 l/d and 597 620 l/d of water while the estimated institutional water demand including illegal students varied between 282 2610 l/d and 406 6580 l/d. The latter further indicates that there is water wastage within the institution because the water supplied monthly to the institution was in mega litres as indicated in the invoices, but the results indicated that the amount of water utilised daily within the institution was in litres, this clearly shows that the respondents under estimated the amount of water they utilise.
The average amount of water used by students residing on campus was 271 l/p/d to 735.5 l/p/d while day scholars and university staff use 55 l/p/d to 142.5 l/p/d. The average amount of water used for cleaning ranged between 1 318.5 l/d to 3 909 l/d while gardening usage ranged between 4600 l/d and 8 600 l/d. The School of Agriculture experimental farm uses 9 270.4 l/d and the university laundry was found to utilise 5 186 l/d. The university laboratories were found to utilise 125 l/d to 215 l/d per practical session with 3 to 4 practical sessions conducted per week. The study found that the total water used by construction workers for domestic purposes
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is 800 l/d. The utilisation trends showed that during the dry seasons, the university population generally used about twice as much water as compared to wet season because municipal water was supplemented by rain water for watering plants and washing the pavement.
The survey results indicated that students residing in the university residences waste more water by allowing the tap to run while brushing teeth, washing dishes, excessive use of water to rinse clothes while doing laundry, opening showers and leaving the water running while waiting for a desired water temperature. Activities such as watering flowers and lawn in an unmonitored manner and pavement washing in which the hose pipe runs for several hours during watering and pavement washing result in water wastage. The university does not have an environmental or water education projects that encourage students and staff to use water efficiently. Water conservation measures are lacking in the institution because there are no policies and procedures that outline how water should be utilised.
The developed water management plan for University of Venda outline the current water consumption, targets for reduction, drivers for reducing water consumption and water reduction strategies. This study recommends that the University targets to reduce potable water usage by 12% in the next 5 years. The latter has been highlighted in the proposed water management plan. The proposed plan further presents a suite of strategies to reduce water usage, improve institution water resources data and to plan for the future. Water utilisation within the institution has not been efficient due to water not being utilised in a sustainable manner. Sub-metering of each building, water awareness campaign, introduction of water utilisation policies, routine inspection and maintenance of infrastructure and appointing an environmental coordinator or working with water experts in the School of Environmental Sciences will help reduce water consumption within the institution. / NRF
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