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An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa
Thesis (MEng)--Stellenbosch University, 2024.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2024
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| _version_ | 1867613752023580672 |
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| access_status_str | Open Access |
| author | Ross, Jordan Ian |
| author2 | Pillay, Visvanathan Lingamvrthi |
| author_browse | Pillay, Visvanathan Lingamvrthi Ross, Jordan Ian |
| author_facet | Pillay, Visvanathan Lingamvrthi Ross, Jordan Ian |
| author_sort | Ross, Jordan Ian |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/130558 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:41:07.950Z |
| license_str | Other β see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar β Stellenbosch University Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar β Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/130558 An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa Ross, Jordan Ian Pillay, Visvanathan Lingamvrthi Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Process Engineering. Water -- Purification -- Reverse osmosis process -- South Africa Ion exchange resins -- South Africa Direct potable reuse -- South Africa Ion exchange resins -- South Africa Water purification chemicals industry -- South Africa Thesis (MEng)--Stellenbosch University, 2024. ENGLISH ABSTRACT: South Africa is expecting a 17% freshwater supply shortfall by 2030 due to climate change, pollution, and water resource mismanagement. This underscores the significance of reusing wastewater to a drinkable standard, known as direct potable reuse (DPR). DPR encompasses primary, secondary, and tertiary water treatment processes. Currently, DPR systems are mainly large-scale and centralized, with primary and secondary treatment at wastewater treatment plants (WWTP) and tertiary treatment at potable water treatment plants (PWTP). However, these centralized facilities are expensive and not suitable for many South African communities. While some communities employ decentralized wastewater treatment, they lack decentralized tertiary treatment processes. Therefore, this research aimed to examine the technical and economic feasibility of implementing small-scale direct potable reuse (ssDPR) systems and propose a tertiary treatment process for use with existing decentralized WWTPs. The study initially identified potentially feasible unit operations from existing literature and assessed each based-on ability to treat secondary effluent to potable water standards using a weighted objective function. It was concluded that microfiltration (MF), nanofiltration (NF), reverse osmosis (RO), and Electrodeionization (EDI) unit operations show the highest theoretical feasibility. Secondly, experimental investigations were conducted on each process assessing cleaning regimes, operational conditions, and effectiveness for removing organic and nutrient contaminants from the same secondary effluent. A MF membrane was initially investigated for the removal of turbidity between fluxes of 24 and 62 πΏπ2ββπ. The NF and RO membranes were evaluated at different feed flow rates [87 to 175 L/h], transmembrane pressures [112.5 to 167.5 kPa] and water recovery (WR) [4 to 70%]. Presently EDI unit operations only exist on industrial scales, thus, a small-scale unit was fabricated with chamber dimensions [4cm x 5cm x 13 cm] and aluminium electrodes. This was evaluated using a 22 factorial design for feed flow [3 to 6 L/h] and current density [0.92 to 2.77 π΄π 2]. An ANOVA analysis, comparing each operations removal efficiencies for significant differences, motivated a combined MF/NF/RO treatment train. Operating the MF at [24 πΏπ2ββπ, 0.82 Pa] the NF at [13.65 πΏπ2ββπ, 137.5 kPa, 64% WR] and the RO at [9.10 πΏπ2ββπ, 137.5 kPa, 64% WR] resulted in a permeate with removals of 99.03% turbidity, 81.39% COD, 93.47% TOC, 95.54% total carbon, 96.31% total inorganic carbon, 84.80% nitrites, 99.87% orthophosphates and near complete removal of pathogen indicators. Although a final ultraviolet light sterilizer is recommended to ensure this. Finally, the project costing of implementing the proposed process at two different scales was undertaken. These costs were evaluated for present and future worth analysis. Over a 15-year lifespan, a home scale implementation has been estimated to have a net present value of -R594 382.59 and a break-even cost of R0.37 per litre. At the scale of a community of ten homes the net present value was calculated as -R12 906 231.26 and a break-even cost per litre of R0.80. The research findings indicate the proposed process shows technical and economic feasibility for implementation. The cost per litre of reclaimed water is competitive with local sources of potable water. Future work on a pilot scale ssDPR system should be done. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2024-03-05T09:43:10Z 2024-04-26T21:59:06Z 2024-03-05T09:43:10Z 2024-04-26T21:59:06Z 2024-03 Thesis https://scholar.sun.ac.za/handle/10019.1/130558 en_ZA en_ZA Stellenbosch University xi, 381 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Water -- Purification -- Reverse osmosis process -- South Africa Ion exchange resins -- South Africa Direct potable reuse -- South Africa Ion exchange resins -- South Africa Water purification chemicals industry -- South Africa Ross, Jordan Ian An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title | An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title_full | An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title_fullStr | An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title_full_unstemmed | An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title_short | An investigation into the techno-economic feasibility of decentralized direct potable reuse (DPR) in South Africa |
| title_sort | investigation into the techno economic feasibility of decentralized direct potable reuse dpr in south africa |
| topic | Water -- Purification -- Reverse osmosis process -- South Africa Ion exchange resins -- South Africa Direct potable reuse -- South Africa Ion exchange resins -- South Africa Water purification chemicals industry -- South Africa |
| url | https://scholar.sun.ac.za/handle/10019.1/130558 |
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