Web usage mining of organisational web sites
- Authors: Oosthuizen, Craig Peter
- Date: 2005
- Subjects: Web usage mining -- South Africa , Internet users -- South Africa , Information visualization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9595 , http://hdl.handle.net/10948/399 , Web usage mining -- South Africa , Internet users -- South Africa , Information visualization
- Description: Web Usage Mining (WUM) can be used to determine whether the information architecture of a web site is structured correctly. Existing WUM tools however, do not indicate which web usage mining algorithms are used or provide effective graphical visualisations of the results obtained. WUM techniques can be used to determine typical navigation patterns of the users of organisational web sites. An organisational web site can be described as a site which has a high level of content. The Computer Science & Information Systems (CS&IS) web site at the Nelson Mandela Metropolitan University (NMMU) is an example of such a web site. The process of combining WUM and information visualisation techniques in order to discover useful information about web usage patterns is called visual web mining. The goal of this research is to discuss the development of a WUM model and a prototype, called WebPatterns, which allows the user to effectively visualise web usage patterns of an organisational web site. This will facilitate determining whether the information architecture of the CS&IS web site is structured correctly. The WUM algorithms used in WebPatterns are association rule mining and sequence analysis. The purpose of association rule mining is to discover relationships between different web pages within a web site. Sequence analysis is used to determine the longest time ordered paths that satisfy a user specified minimum frequency. A radial tree layout is used in WebPatterns to visualise the static structure of the organisational web site. The structure of the web site is laid out radially, with the home page in the middle and other pages positioned in circles at various levels around it. Colour and other visual cues are used to show the results of the WUM algorithms. User testing was used to determine the effectiveness and usefulness of WebPatterns for visualising web usage patterns. The results of the user testing clearly show that the participants were highly satisfied with the visual design and information provided by WebPatterns. All the participants also indicated that they would like to use WebPatterns in the future. Analysis of the web usage patterns presented by WebPatterns was used to determine that the information architecture of the CS&IS web site can be restructured to better facilitate information retrieval. Changes to the CS&IS web site web were suggested, included placing embedded hyperlinks on the home page to the frequently accessed sections of the web site.
- Full Text:
- Date Issued: 2005
- Authors: Oosthuizen, Craig Peter
- Date: 2005
- Subjects: Web usage mining -- South Africa , Internet users -- South Africa , Information visualization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9595 , http://hdl.handle.net/10948/399 , Web usage mining -- South Africa , Internet users -- South Africa , Information visualization
- Description: Web Usage Mining (WUM) can be used to determine whether the information architecture of a web site is structured correctly. Existing WUM tools however, do not indicate which web usage mining algorithms are used or provide effective graphical visualisations of the results obtained. WUM techniques can be used to determine typical navigation patterns of the users of organisational web sites. An organisational web site can be described as a site which has a high level of content. The Computer Science & Information Systems (CS&IS) web site at the Nelson Mandela Metropolitan University (NMMU) is an example of such a web site. The process of combining WUM and information visualisation techniques in order to discover useful information about web usage patterns is called visual web mining. The goal of this research is to discuss the development of a WUM model and a prototype, called WebPatterns, which allows the user to effectively visualise web usage patterns of an organisational web site. This will facilitate determining whether the information architecture of the CS&IS web site is structured correctly. The WUM algorithms used in WebPatterns are association rule mining and sequence analysis. The purpose of association rule mining is to discover relationships between different web pages within a web site. Sequence analysis is used to determine the longest time ordered paths that satisfy a user specified minimum frequency. A radial tree layout is used in WebPatterns to visualise the static structure of the organisational web site. The structure of the web site is laid out radially, with the home page in the middle and other pages positioned in circles at various levels around it. Colour and other visual cues are used to show the results of the WUM algorithms. User testing was used to determine the effectiveness and usefulness of WebPatterns for visualising web usage patterns. The results of the user testing clearly show that the participants were highly satisfied with the visual design and information provided by WebPatterns. All the participants also indicated that they would like to use WebPatterns in the future. Analysis of the web usage patterns presented by WebPatterns was used to determine that the information architecture of the CS&IS web site can be restructured to better facilitate information retrieval. Changes to the CS&IS web site web were suggested, included placing embedded hyperlinks on the home page to the frequently accessed sections of the web site.
- Full Text:
- Date Issued: 2005
Weather neutral models for short-term electricity demand forecasting
- Authors: Nyulu, Thandekile
- Date: 2013
- Subjects: Electric power consumption -- Forecasting -- Mathematical models , Forecasting -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10578 , http://hdl.handle.net/10948/d1018751
- Description: Energy demand forecasting, and specifically electricity demand forecasting, is a fun-damental feature in both industry and research. Forecasting techniques assist all electricity market participants in accurate planning, selling and purchasing decisions and strategies. Generation and distribution of electricity require appropriate, precise and accurate forecasting methods. Also accurate forecasting models assist producers, researchers and economists to make proper and beneficial future decisions. There are several research papers, which investigate this fundamental aspect and attempt var-ious statistical techniques. Although weather and economic effects have significant influences on electricity demand, in this study they are purposely eliminated from investigation. This research considers calendar-related effects such as months of the year, weekdays and holidays (that is, public holidays, the day before a public holiday, the day after a public holiday, school holidays, university holidays, Easter holidays and major religious holidays) and includes university exams, general election days, day after elections, and municipal elections in the analysis. Regression analysis, cate-gorical regression and auto-regression are used to illustrate the relationships between response variable and explanatory variables. The main objective of the investigation was to build forecasting models based on this calendar data only and to observe how accurate the models can be without taking into account weather effects and economic effects, hence weather neutral models. Weather and economic factors have to be forecasted, and these forecasts are not so accurate and calendar events are known for sure (error-free). Collecting data for weather and economic factors is costly and time consuming, while obtaining calendar data is relatively easy.
- Full Text:
- Date Issued: 2013
- Authors: Nyulu, Thandekile
- Date: 2013
- Subjects: Electric power consumption -- Forecasting -- Mathematical models , Forecasting -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10578 , http://hdl.handle.net/10948/d1018751
- Description: Energy demand forecasting, and specifically electricity demand forecasting, is a fun-damental feature in both industry and research. Forecasting techniques assist all electricity market participants in accurate planning, selling and purchasing decisions and strategies. Generation and distribution of electricity require appropriate, precise and accurate forecasting methods. Also accurate forecasting models assist producers, researchers and economists to make proper and beneficial future decisions. There are several research papers, which investigate this fundamental aspect and attempt var-ious statistical techniques. Although weather and economic effects have significant influences on electricity demand, in this study they are purposely eliminated from investigation. This research considers calendar-related effects such as months of the year, weekdays and holidays (that is, public holidays, the day before a public holiday, the day after a public holiday, school holidays, university holidays, Easter holidays and major religious holidays) and includes university exams, general election days, day after elections, and municipal elections in the analysis. Regression analysis, cate-gorical regression and auto-regression are used to illustrate the relationships between response variable and explanatory variables. The main objective of the investigation was to build forecasting models based on this calendar data only and to observe how accurate the models can be without taking into account weather effects and economic effects, hence weather neutral models. Weather and economic factors have to be forecasted, and these forecasts are not so accurate and calendar events are known for sure (error-free). Collecting data for weather and economic factors is costly and time consuming, while obtaining calendar data is relatively easy.
- Full Text:
- Date Issued: 2013
Weak form market efficiency of the Johannesburg Stock Exchange : pre during and post the 2008 global financial crisis
- Authors: Futshane, Olwetu
- Date: 2016
- Subjects: Global Financial Crisis, 2008-2009 Efficient market theory Random walks (Mathematics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10353/11895 , vital:39116
- Description: The importance of the efficiency of the stock market cannot be underestimated, given that it brings together those who demand and supply development finance. It is against this background that this study focused on analysing the weak form efficiency of the Johannesburg Stock Exchange for the period 2005 to 2016. The study reviewed the theoretical and empirical literatures which have tried to examine the market efficiency of the Johannesburg stock exchange and whether the JSE follows that random walk. Based on the review of literature, several methodologies such as (unit root tests, autocorrelation test) were employed in the study obtaining robust results that the JSE price indices (All Share, Resources and Financials) follow the random walk process. To further confirm the findings in this research, the variance ratio test is conducted under heteroscedasticity and homoscedasticity it also strongly verified that the existence of a random walk process cannot be rejected in the JSE. The empirical results from all the various tests reveal that the null hypothesis of random walk cannot be rejected. These results thus suggest that the JSE is efficient in its weak form. This commends all the measures which have been carried out to ensure that the market is efficient.
- Full Text:
- Date Issued: 2016
- Authors: Futshane, Olwetu
- Date: 2016
- Subjects: Global Financial Crisis, 2008-2009 Efficient market theory Random walks (Mathematics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10353/11895 , vital:39116
- Description: The importance of the efficiency of the stock market cannot be underestimated, given that it brings together those who demand and supply development finance. It is against this background that this study focused on analysing the weak form efficiency of the Johannesburg Stock Exchange for the period 2005 to 2016. The study reviewed the theoretical and empirical literatures which have tried to examine the market efficiency of the Johannesburg stock exchange and whether the JSE follows that random walk. Based on the review of literature, several methodologies such as (unit root tests, autocorrelation test) were employed in the study obtaining robust results that the JSE price indices (All Share, Resources and Financials) follow the random walk process. To further confirm the findings in this research, the variance ratio test is conducted under heteroscedasticity and homoscedasticity it also strongly verified that the existence of a random walk process cannot be rejected in the JSE. The empirical results from all the various tests reveal that the null hypothesis of random walk cannot be rejected. These results thus suggest that the JSE is efficient in its weak form. This commends all the measures which have been carried out to ensure that the market is efficient.
- Full Text:
- Date Issued: 2016
We are yet to kill the cattle
- Authors: Orleyn, Rithuli
- Date: 2019
- Subjects: South African fiction (English)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92769 , vital:30746
- Description: My novella comprises inter-linked fragments that combine fiction, autobiography and creative non-fiction. Ranging fluidly from pre-colonial times to the present, and largely set in South Africa but cutting across the native/diaspora divide, the project draws on historical and archival documents, found and fictive letters, oral testimonies and inadmissible facts, mythologies, ghost voices and fictional speculation. It uses the slim slippery voice of autobiography to cast a big shadow of doubt on the certitudes of authorial truth, harnessing multiple voices to disorient settled notions about self/other, black/white and man/machine. My intention is to explore possibilities of being that exceed the human. I draw inspiration from Zoë Wicomb's novella, You Can’t Get Lost In Cape Town, Mariama Ba’s So Long a Letter and Mikhail Shishkin’s letter-narratives in Maidenhair. The narrative voice that threads stand-alone fragments seeks to express the demotics of subjects in search of a language for their unlanguaged ‘grammar of suffering’.
- Full Text:
- Date Issued: 2019
- Authors: Orleyn, Rithuli
- Date: 2019
- Subjects: South African fiction (English)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92769 , vital:30746
- Description: My novella comprises inter-linked fragments that combine fiction, autobiography and creative non-fiction. Ranging fluidly from pre-colonial times to the present, and largely set in South Africa but cutting across the native/diaspora divide, the project draws on historical and archival documents, found and fictive letters, oral testimonies and inadmissible facts, mythologies, ghost voices and fictional speculation. It uses the slim slippery voice of autobiography to cast a big shadow of doubt on the certitudes of authorial truth, harnessing multiple voices to disorient settled notions about self/other, black/white and man/machine. My intention is to explore possibilities of being that exceed the human. I draw inspiration from Zoë Wicomb's novella, You Can’t Get Lost In Cape Town, Mariama Ba’s So Long a Letter and Mikhail Shishkin’s letter-narratives in Maidenhair. The narrative voice that threads stand-alone fragments seeks to express the demotics of subjects in search of a language for their unlanguaged ‘grammar of suffering’.
- Full Text:
- Date Issued: 2019
Wavelength-modulation spectroscopy for the evaluation of the photoresponse of solar cells
- Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Authors: Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Date: 2016
- Subjects: Gallium arsenide semiconductors , Solar cells , Modulation spectroscopy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7244 , vital:21312
- Description: This study describes the development of a wavelength-modulation spectroscopy technique for the evaluation of solar cell devices. In particular, the technique is used to investigate the sub-bandgap response associated with the incorporation of GaSb quantum rings into the active region of a conventional GaAs p-i-n solar cell. These GaSb/GaAs quantum ring solar cells are a class of third generation cells, with the potential to exceed the Shockley-Queisser efficiency limit of single junction devices. Wavelength-modulation spectroscopy (WMS) techniques involve the modulation of the wavelength of a pseudo-monochromatic light source, with the resulting variation in the measured photocurrent then being a measure of the differential optical response of the solar cell. Although the conventional photocurrent spectrum of a solar cell is a good measure of the optical response characteristics, the differential technique gives supplemental detail related to the absorption spectrum. In addition to the basic WMS setup, we also developed an in situ flux correction module to ensure that a constant excitation intensity is maintained during the wavelength modulation. The excitation source inherently has a spectral dependence that leads to an undesirable contribution to the photocurrent signal. The operation of the flux corrected WMS setup has been demonstrated by photocurrent and photo-capacitance response measurements to obtain the differential quantum efficiency and charging characteristics of the quantum ring solar cells.
- Full Text:
- Date Issued: 2016
- Authors: Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Date: 2016
- Subjects: Gallium arsenide semiconductors , Solar cells , Modulation spectroscopy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7244 , vital:21312
- Description: This study describes the development of a wavelength-modulation spectroscopy technique for the evaluation of solar cell devices. In particular, the technique is used to investigate the sub-bandgap response associated with the incorporation of GaSb quantum rings into the active region of a conventional GaAs p-i-n solar cell. These GaSb/GaAs quantum ring solar cells are a class of third generation cells, with the potential to exceed the Shockley-Queisser efficiency limit of single junction devices. Wavelength-modulation spectroscopy (WMS) techniques involve the modulation of the wavelength of a pseudo-monochromatic light source, with the resulting variation in the measured photocurrent then being a measure of the differential optical response of the solar cell. Although the conventional photocurrent spectrum of a solar cell is a good measure of the optical response characteristics, the differential technique gives supplemental detail related to the absorption spectrum. In addition to the basic WMS setup, we also developed an in situ flux correction module to ensure that a constant excitation intensity is maintained during the wavelength modulation. The excitation source inherently has a spectral dependence that leads to an undesirable contribution to the photocurrent signal. The operation of the flux corrected WMS setup has been demonstrated by photocurrent and photo-capacitance response measurements to obtain the differential quantum efficiency and charging characteristics of the quantum ring solar cells.
- Full Text:
- Date Issued: 2016
Wattle we do? alien eradication and the 'ecology of fear' on the fringes of a world heritage site, South Africa
- Authors: Merron, James Lawrence
- Date: 2010
- Subjects: Wattles (Plants) -- South Africa -- Eastern Cape Invasive plants -- South Africa -- Eastern Cape South Africa -- Social conditions -- 1994- South Africa -- Politics and government -- 1994- Environmental degradation -- South Africa -- Eastern Cape World Heritage areas -- South Africa -- Eastern Cape Environmentalism -- South Africa -- Eastern Cape -- Social aspects Environmentalism -- South Africa -- Eastern Cape -- Political aspects Social ecology -- South Africa -- Eastern Cape Human ecology -- South Africa -- Eastern Cape Applied anthropology -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape -- Social aspects Nature -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2092 , http://hdl.handle.net/10962/d1002655
- Description: In their article ―Naturing the Nation: Aliens, the Apocalypse and the Post Colonial State (2001) Jean and John Comaroff look at ―the contemporary predicament of South Africa through the prism of environmental catastrophe. Through it they reveal the context in which alien plants have become an urgent affair of the state. Following their lead, I show how alien plants (particularly Australian wattle) continue to provide grounds for new social and political aspirations in South Africa, though in a different setting. With reference to a group of private landowners on the fringe of a World Heritage Site -- the Baviaanskloof Mega-Reserve, Eastern Cape, South Africa -- I show how an increasingly apocalyptic and xenophobic environmental agenda has influenced local activists seeking to address social and ecological issues in tandem with alien-eradication. These local activists adhere to a particular brand of environmentalism which Milton (1993) argues can be considered a social, cultural and religious phenomenon. The subjects of my main empirical investigation offer practical ways of achieving a transformational end through a new ritual activity in relation to a spread and exchange of environmental ideas and practices on a world-wide scale. On the ground this group practices ecosocietal restoration through which they aspire to mend the bond between people and the land in a spiritual and moral sense, bolstering intrinsic incentives for environmental stewardship and achieving ―cultural reconciliation in an attempt to reimagine what South Africa could be.
- Full Text:
- Date Issued: 2010
- Authors: Merron, James Lawrence
- Date: 2010
- Subjects: Wattles (Plants) -- South Africa -- Eastern Cape Invasive plants -- South Africa -- Eastern Cape South Africa -- Social conditions -- 1994- South Africa -- Politics and government -- 1994- Environmental degradation -- South Africa -- Eastern Cape World Heritage areas -- South Africa -- Eastern Cape Environmentalism -- South Africa -- Eastern Cape -- Social aspects Environmentalism -- South Africa -- Eastern Cape -- Political aspects Social ecology -- South Africa -- Eastern Cape Human ecology -- South Africa -- Eastern Cape Applied anthropology -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape -- Social aspects Nature -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2092 , http://hdl.handle.net/10962/d1002655
- Description: In their article ―Naturing the Nation: Aliens, the Apocalypse and the Post Colonial State (2001) Jean and John Comaroff look at ―the contemporary predicament of South Africa through the prism of environmental catastrophe. Through it they reveal the context in which alien plants have become an urgent affair of the state. Following their lead, I show how alien plants (particularly Australian wattle) continue to provide grounds for new social and political aspirations in South Africa, though in a different setting. With reference to a group of private landowners on the fringe of a World Heritage Site -- the Baviaanskloof Mega-Reserve, Eastern Cape, South Africa -- I show how an increasingly apocalyptic and xenophobic environmental agenda has influenced local activists seeking to address social and ecological issues in tandem with alien-eradication. These local activists adhere to a particular brand of environmentalism which Milton (1993) argues can be considered a social, cultural and religious phenomenon. The subjects of my main empirical investigation offer practical ways of achieving a transformational end through a new ritual activity in relation to a spread and exchange of environmental ideas and practices on a world-wide scale. On the ground this group practices ecosocietal restoration through which they aspire to mend the bond between people and the land in a spiritual and moral sense, bolstering intrinsic incentives for environmental stewardship and achieving ―cultural reconciliation in an attempt to reimagine what South Africa could be.
- Full Text:
- Date Issued: 2010
Wattle and pineapple residues as oyster mushroom substrates and the utilization of spent substrate in potted tomato production
- Hlerema, Igenicious Nicholas
- Authors: Hlerema, Igenicious Nicholas
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc Agric (Horticultural Science)
- Identifier: vital:11887 , http://hdl.handle.net/10353/d1016199
- Description: Cultivating oyster mushrooms (Pleurotus ostreatus) could have multiple advantages. For example, it can contribute to food security and malnutrition eradication, as a source of healthy and nutritionally rich food. Feeding on lignocellulosic crop/plant residues, these mushroom species also convert waste materials into a wide diversity of products which have multi-beneficial effects to human beings: serving as animal feed and fertiliser, and for protecting and regenerating the environment. Therefore, objectives of the current research were (1) to investigate the use of the rapidly increasing alien plants (Acacia spp.) in South Africa in cultivating of oyster mushroom for dual benefits, income generating and controlling the population of the alien (invasive) plants; (2) to evaluate the use of pineapple residue in the Eastern Cape as sole substrate or as a supplement in the cultivation of oyster mushroom; (3) to determine the effect of mushroom spent substrate, as organic growing media, on growth of tomatoes and controlling nematode population. In an experiment to investigate yield performance of oyster mushroom (Pleurotus ostreatus HK 35) grown on three acacia species [black wattle (BW: Acacia mearnsii) , silver wattle (SW: A. dealbata) and green wattle (GW: A. decurrens)] used as substrates either mixed with 50% maize bran (MB) or 50% wheat straw (WS).
- Full Text:
- Date Issued: 2013
- Authors: Hlerema, Igenicious Nicholas
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc Agric (Horticultural Science)
- Identifier: vital:11887 , http://hdl.handle.net/10353/d1016199
- Description: Cultivating oyster mushrooms (Pleurotus ostreatus) could have multiple advantages. For example, it can contribute to food security and malnutrition eradication, as a source of healthy and nutritionally rich food. Feeding on lignocellulosic crop/plant residues, these mushroom species also convert waste materials into a wide diversity of products which have multi-beneficial effects to human beings: serving as animal feed and fertiliser, and for protecting and regenerating the environment. Therefore, objectives of the current research were (1) to investigate the use of the rapidly increasing alien plants (Acacia spp.) in South Africa in cultivating of oyster mushroom for dual benefits, income generating and controlling the population of the alien (invasive) plants; (2) to evaluate the use of pineapple residue in the Eastern Cape as sole substrate or as a supplement in the cultivation of oyster mushroom; (3) to determine the effect of mushroom spent substrate, as organic growing media, on growth of tomatoes and controlling nematode population. In an experiment to investigate yield performance of oyster mushroom (Pleurotus ostreatus HK 35) grown on three acacia species [black wattle (BW: Acacia mearnsii) , silver wattle (SW: A. dealbata) and green wattle (GW: A. decurrens)] used as substrates either mixed with 50% maize bran (MB) or 50% wheat straw (WS).
- Full Text:
- Date Issued: 2013
Water, salt and nutrient budgets of the Swartkops and Sundays river estuaries using the loicz biogeochemical budgeting protocol
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
Water supply development decision-making in South Africa
- Authors: Preston, Ian Robert
- Date: 2016
- Subjects: Water security -- South Africa , Water resources development -- South Africa -- Cost effectiveness , Water consumption -- Economic aspects -- South Africa , Water-supply -- South Africa -- Management , Water-supply -- South Africa -- Decision making
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1210 , http://hdl.handle.net/10962/d1020848
- Description: Balancing water demand and supply in South Africa involves high levels of uncertainty. The Department of Water and Sanitation (DWS) is responsible for making decisions to either increase water supply or decrease water demand so as to ensure that sufficient water is available, when and where it is needed. However, no retrospective analyses of such decisions have been found. One way to assess such decisions is to evaluate the associated costs and benefits thereof. Therefore the primary aim of this study is to evaluate the costs and benefits of selected water supply options, and of the decision-making associated with those options. In order to achieve this purpose, four case studies were analysed within a mixed-methods research paradigm, which used both quantitative and qualitative methods, including unit reference value (URV) analysis, inter- and intra-case analysis and content analysis to examine the success of the decisions made. The four case studies were conducted on the Inyaka, Nandoni, Berg and De Hoop dams and their catchments. Firstly, estimated and actual project costs were compared using unit reference analysis and inter-case analyses. Secondly, the reduction of mean annual runoff (MAR) caused by invasive alien plants (IAPs) and the cost of clearing them in the dam catchments were evaluated using inter-case analyses. Information thus gathered was used together with data from DWS documentation and the results of interviews with ten key specialists, to analyse the decision-making process that led to the decision to build De Hoop Dam (the most recent case study). The rational decision-making model (RDMM) was used as a framework within which to analyse and evaluate this decision-making process. This study has also demonstrated how the RDMM can be used to assess decision-making associated with water supply development. The results of this study show that there is considerable variation of estimated costs (at the time that the decision to build the dam was taken) in relation to the actual costs of building the dams and that Ministers were not put in a position to understand the full long-term costs or the opportunity costs of the proposed dams. Furthermore, the most recent IAP data (2008) shows that the impact on water security by IAPs could not offset the water security resulting from building each of the four dams. However, if IAP management is not continued in these catchments, the projected reduction of MAR by IAPs will compromise water security within 45 years. Given the almost exponential spread and densification of IAPs, together with their long-term impact on MAR and increased costs of controlling them, it is clear that IAP management should have been factored into water supply decision-making from the outset. In the analysis of the decision to build the De Hoop Dam, the results show that while the decision-making process that culminated in the decision to build the dam did not follow the steps of the RDMM, DWS appears to have followed a somewhat similar approach. It was found that while there was a need for the provision of additional water in the Olifants catchment, this need was overstated and the resulting overestimation caused the scale and size of the dam to be larger than it could and probably should have been. Additionally, it appears that DWS‘s decision to build the De Hoop Dam themselves, rather than having it built by the private sector, may have been less than optimal. It is recommended that, in future decision-making, DWS needs to incorporate multiple alternative options into the same solution, and to ensure that decision-makers are put into a position to make informed decisions, including adequate consideration of externalities. Furthermore, DWS needs to employ decision-making models such as the RDMM to facilitate retrospective analyses to improve their institutional knowledge. Keywords: water resources management, dams, invasive alien plants, decision-making, unit reference values, rational decision-making model.
- Full Text:
- Date Issued: 2016
- Authors: Preston, Ian Robert
- Date: 2016
- Subjects: Water security -- South Africa , Water resources development -- South Africa -- Cost effectiveness , Water consumption -- Economic aspects -- South Africa , Water-supply -- South Africa -- Management , Water-supply -- South Africa -- Decision making
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1210 , http://hdl.handle.net/10962/d1020848
- Description: Balancing water demand and supply in South Africa involves high levels of uncertainty. The Department of Water and Sanitation (DWS) is responsible for making decisions to either increase water supply or decrease water demand so as to ensure that sufficient water is available, when and where it is needed. However, no retrospective analyses of such decisions have been found. One way to assess such decisions is to evaluate the associated costs and benefits thereof. Therefore the primary aim of this study is to evaluate the costs and benefits of selected water supply options, and of the decision-making associated with those options. In order to achieve this purpose, four case studies were analysed within a mixed-methods research paradigm, which used both quantitative and qualitative methods, including unit reference value (URV) analysis, inter- and intra-case analysis and content analysis to examine the success of the decisions made. The four case studies were conducted on the Inyaka, Nandoni, Berg and De Hoop dams and their catchments. Firstly, estimated and actual project costs were compared using unit reference analysis and inter-case analyses. Secondly, the reduction of mean annual runoff (MAR) caused by invasive alien plants (IAPs) and the cost of clearing them in the dam catchments were evaluated using inter-case analyses. Information thus gathered was used together with data from DWS documentation and the results of interviews with ten key specialists, to analyse the decision-making process that led to the decision to build De Hoop Dam (the most recent case study). The rational decision-making model (RDMM) was used as a framework within which to analyse and evaluate this decision-making process. This study has also demonstrated how the RDMM can be used to assess decision-making associated with water supply development. The results of this study show that there is considerable variation of estimated costs (at the time that the decision to build the dam was taken) in relation to the actual costs of building the dams and that Ministers were not put in a position to understand the full long-term costs or the opportunity costs of the proposed dams. Furthermore, the most recent IAP data (2008) shows that the impact on water security by IAPs could not offset the water security resulting from building each of the four dams. However, if IAP management is not continued in these catchments, the projected reduction of MAR by IAPs will compromise water security within 45 years. Given the almost exponential spread and densification of IAPs, together with their long-term impact on MAR and increased costs of controlling them, it is clear that IAP management should have been factored into water supply decision-making from the outset. In the analysis of the decision to build the De Hoop Dam, the results show that while the decision-making process that culminated in the decision to build the dam did not follow the steps of the RDMM, DWS appears to have followed a somewhat similar approach. It was found that while there was a need for the provision of additional water in the Olifants catchment, this need was overstated and the resulting overestimation caused the scale and size of the dam to be larger than it could and probably should have been. Additionally, it appears that DWS‘s decision to build the De Hoop Dam themselves, rather than having it built by the private sector, may have been less than optimal. It is recommended that, in future decision-making, DWS needs to incorporate multiple alternative options into the same solution, and to ensure that decision-makers are put into a position to make informed decisions, including adequate consideration of externalities. Furthermore, DWS needs to employ decision-making models such as the RDMM to facilitate retrospective analyses to improve their institutional knowledge. Keywords: water resources management, dams, invasive alien plants, decision-making, unit reference values, rational decision-making model.
- Full Text:
- Date Issued: 2016
Water service delivery in Harare: a willingness to pay (WTP) analysis
- Authors: Mugomba, Lynsey M
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4120 , vital:20614
- Description: In 2008-2009, Harare (Zimbabwe) was the centre of the worst cholera outbreak in Africa in the past fifteen years. A key reason cited was the lack of adequate water service delivery by the Harare City Council (HCC). Harare requires an optimum supply of 1 400 mega litres (ML) of water daily but the HCC has capacity to produce 650ML and after leakages and theft, only 400ML reaches consumers. This inadequacy compromised the hygiene of residents and forced them to resort to unsafe water sources. Coupled with a failing healthcare system, the outbreak resulted in over 4 000 deaths and further affected 100 000 people. The HCC attributes its poor service delivery to the lack of funds rendering them unable to adequately increase capacity and refurbish existing infrastructure (treatment plants and pipelines). This thesis serves to explore whether the residents of Harare (and surrounding satellite towns) would be willing to pay monthly contributions towards the USD$2.5 billion needed for various water capacity and infrastructure projects to ease the water crisis in Harare. The study analyses the water problem using a framework on the typical stages of water provision. The research also places an emphasis on the key social, economic and political factors that are contributing to the problem in Harare. Upon closer inspection, it was seen that the financial problems that the HCC is having are not only due to the economy, but poor management and transparency structures are also to blame. For various reasons, the government has largely lost its credibility with its citizens, leading some to conclude that the government’s actions reflect those of a predatory state. The contingent valuation method (willingness to pay-WTP) was used in conjunction with the dichotomous choice referendum. The binary probit model was used to help assess the degree to which different variables influenced the respondent’s decision to contribute to the needed funds. In spite of the seeming lack of trust, it was found that approximately 66.19% of the respondents were willing to pay. Amongst those willing, the mean willingness to pay amount was approximately USD$7 monthly per household.
- Full Text:
- Date Issued: 2016
- Authors: Mugomba, Lynsey M
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4120 , vital:20614
- Description: In 2008-2009, Harare (Zimbabwe) was the centre of the worst cholera outbreak in Africa in the past fifteen years. A key reason cited was the lack of adequate water service delivery by the Harare City Council (HCC). Harare requires an optimum supply of 1 400 mega litres (ML) of water daily but the HCC has capacity to produce 650ML and after leakages and theft, only 400ML reaches consumers. This inadequacy compromised the hygiene of residents and forced them to resort to unsafe water sources. Coupled with a failing healthcare system, the outbreak resulted in over 4 000 deaths and further affected 100 000 people. The HCC attributes its poor service delivery to the lack of funds rendering them unable to adequately increase capacity and refurbish existing infrastructure (treatment plants and pipelines). This thesis serves to explore whether the residents of Harare (and surrounding satellite towns) would be willing to pay monthly contributions towards the USD$2.5 billion needed for various water capacity and infrastructure projects to ease the water crisis in Harare. The study analyses the water problem using a framework on the typical stages of water provision. The research also places an emphasis on the key social, economic and political factors that are contributing to the problem in Harare. Upon closer inspection, it was seen that the financial problems that the HCC is having are not only due to the economy, but poor management and transparency structures are also to blame. For various reasons, the government has largely lost its credibility with its citizens, leading some to conclude that the government’s actions reflect those of a predatory state. The contingent valuation method (willingness to pay-WTP) was used in conjunction with the dichotomous choice referendum. The binary probit model was used to help assess the degree to which different variables influenced the respondent’s decision to contribute to the needed funds. In spite of the seeming lack of trust, it was found that approximately 66.19% of the respondents were willing to pay. Amongst those willing, the mean willingness to pay amount was approximately USD$7 monthly per household.
- Full Text:
- Date Issued: 2016
Water service delivery for improved quality of life in the Mbizana Local Municipal
- Authors: Mpange, Zolisa Bavuyise
- Date: 2012
- Subjects: Public administration -- South Africa -- Eastern Cape , Water-supply -- South Africa -- Eastern Cape , Municipal services -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9146 , http://hdl.handle.net/10948/d1018891
- Description: This study deals with water service delivery for improved quality of life in the Mbizana Local Municipality. The study sets out to determine how the inner workings of water service delivery work in the Mbizana Local Municipality, situated in the Eastern Cape, and how this should function in terms of South African legislation. The objectives of the study are to understand the current state of water service delivery in the Mbizana Local Municipality, finding out information about South African legislation regarding the ideal state of water service delivery, and recommending development programmes to improve water service delivery. This study is about understanding trends in the body of scientific knowledge or literature, and studying (as objects) the ideas and writings of other scholars. No empirical study was conducted. The research methodology for this study is descriptive, with data sourced from available literature. The findings in this study indicate that backlogs for water service delivery remain high in the Mbizana Local Municipality. Regrettably, the situation has worsened since 2004; backlogs have shifted from 45 percent to 94 percent of households with no access to tap water. A number of normative criteria to deal with the research problem were extracted from available literature, from which conclusions were drawn and recommendations made.
- Full Text:
- Date Issued: 2012
- Authors: Mpange, Zolisa Bavuyise
- Date: 2012
- Subjects: Public administration -- South Africa -- Eastern Cape , Water-supply -- South Africa -- Eastern Cape , Municipal services -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9146 , http://hdl.handle.net/10948/d1018891
- Description: This study deals with water service delivery for improved quality of life in the Mbizana Local Municipality. The study sets out to determine how the inner workings of water service delivery work in the Mbizana Local Municipality, situated in the Eastern Cape, and how this should function in terms of South African legislation. The objectives of the study are to understand the current state of water service delivery in the Mbizana Local Municipality, finding out information about South African legislation regarding the ideal state of water service delivery, and recommending development programmes to improve water service delivery. This study is about understanding trends in the body of scientific knowledge or literature, and studying (as objects) the ideas and writings of other scholars. No empirical study was conducted. The research methodology for this study is descriptive, with data sourced from available literature. The findings in this study indicate that backlogs for water service delivery remain high in the Mbizana Local Municipality. Regrettably, the situation has worsened since 2004; backlogs have shifted from 45 percent to 94 percent of households with no access to tap water. A number of normative criteria to deal with the research problem were extracted from available literature, from which conclusions were drawn and recommendations made.
- Full Text:
- Date Issued: 2012
Water security amongst impoverished households in the Sundays River Valley Municipality : community experiences and perspectives
- Authors: Molony, Lara
- Date: 2015
- Subjects: Water security -- South Africa -- Sundays River (Eastern Cape) , Poor -- South Africa -- Sundays River (Eastern Cape) , Water-supply -- Management , Water consumption -- South Africa -- Sundays River (Eastern Cape) , Water quality management -- South Africa -- Sundays River (Eastern Cape) , Municipal services -- South Africa -- Sundays River (Eastern Cape) , Water quality -- South Africa -- Sundays River (Eastern Cape) , Municipal water supply -- South Africa -- Sundays River (Eastern Cape) , Political ecology -- South Africa -- Sundays River (Eastern Cape)
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4788 , http://hdl.handle.net/10962/d1018932
- Description: Water security is influenced by the complex interplay between ecological, socio-political, governance and water management systems. Achieving water security is essential for ensuring sustainable development, and challenges with water security are closely linked to the overall experience of poverty that many countries throughout the world, including South Africa, confront. These problems can broadly be understood through three main factors: water availability, access and usage; water governance and management underpin these factors. Water insecurity can often be seen in townships within South Africa, where water service delivery and water access is precarious. This study provides a lens into the water security experiences of two poor township communities in the Sundays River Valley Municipality (SRVM) namely Nomathamsanqa in Addo and Aquapark in Kirkwood. The research assessed water security patterns amongst RDP, township and informal settlement households serviced by the SRVM and found that communities face severe water security problems. Specifically, it was found that all township households encounter frequent water shortages, cuts in municipal water supply and water quality concerns. Issues around the payment for water and dissatisfaction with water service delivery also emerged. The purpose of this research was to allow for community experiences and perspectives to be expressed in an academic space that has previously been dominated by water management and policy makers. The study concludes that these communities within the SRVM experience significant challenges in securing safe water and these are largely due to social water scarcity issues and the difficulties the municipality faces concerning water service delivery.
- Full Text:
- Date Issued: 2015
- Authors: Molony, Lara
- Date: 2015
- Subjects: Water security -- South Africa -- Sundays River (Eastern Cape) , Poor -- South Africa -- Sundays River (Eastern Cape) , Water-supply -- Management , Water consumption -- South Africa -- Sundays River (Eastern Cape) , Water quality management -- South Africa -- Sundays River (Eastern Cape) , Municipal services -- South Africa -- Sundays River (Eastern Cape) , Water quality -- South Africa -- Sundays River (Eastern Cape) , Municipal water supply -- South Africa -- Sundays River (Eastern Cape) , Political ecology -- South Africa -- Sundays River (Eastern Cape)
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4788 , http://hdl.handle.net/10962/d1018932
- Description: Water security is influenced by the complex interplay between ecological, socio-political, governance and water management systems. Achieving water security is essential for ensuring sustainable development, and challenges with water security are closely linked to the overall experience of poverty that many countries throughout the world, including South Africa, confront. These problems can broadly be understood through three main factors: water availability, access and usage; water governance and management underpin these factors. Water insecurity can often be seen in townships within South Africa, where water service delivery and water access is precarious. This study provides a lens into the water security experiences of two poor township communities in the Sundays River Valley Municipality (SRVM) namely Nomathamsanqa in Addo and Aquapark in Kirkwood. The research assessed water security patterns amongst RDP, township and informal settlement households serviced by the SRVM and found that communities face severe water security problems. Specifically, it was found that all township households encounter frequent water shortages, cuts in municipal water supply and water quality concerns. Issues around the payment for water and dissatisfaction with water service delivery also emerged. The purpose of this research was to allow for community experiences and perspectives to be expressed in an academic space that has previously been dominated by water management and policy makers. The study concludes that these communities within the SRVM experience significant challenges in securing safe water and these are largely due to social water scarcity issues and the difficulties the municipality faces concerning water service delivery.
- Full Text:
- Date Issued: 2015
Water requirements and distribution of Ammophila arenaria and Scaevola plumieri on South African coastal dunes
- Authors: Peter, Craig Ingram
- Date: 2000
- Subjects: Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4219 , http://hdl.handle.net/10962/d1003788 , Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Description: Phenomenological models are presented which predicts transpiration rates (E) of individual leaves of Scaevola plumieri, an indigenous dune pioneer, and Ammophila arenaria, an exotic grass species introduced to stabilise mobile sand. In both cases E is predictably related to atmospheric vapour pressure deficit (VPD). VPD is calculated from measurements of ambient temperature and humidity, hence, where these two environmental variables are known, E can be calculated. Possible physiological reasons for the relationships of E to VPD in both species are discussed. Scaling from measurements of E at the leaf level to the canopy level is achieved by summing the leaf area of the canopy in question. E is predicted for the entire canopy leaf area by extrapolation to this larger leaf area. Predicted transpiration rates of individual shoot within the canopy were tested gravimetrically and shown to be accurate in the case of S. plumieri, but less so in the case of A. arenaria. Using this model, the amount of water used by a known area of sand dune is shown to be less than the rainfall input in the case of S. plumieri in wet and dry years. The water use of A. arenaria exceeds rainfall in the low-rainfall year of 1995, while in 1998 rainfall input is slightly higher than water extraction by the plants. Using a geographic information system (GIS), regional maps (surfaces) of transpiration were calculated from surfaces of mean monthly temperature and mean monthly relative humidity. Monthly surfaces of transpiration were subtracted from the monthly median rainfall to produce a surface of mean monthly water deficit. Areas of water surpluses along the coast correspond with the recorded distribution of both species in the seasons that the plants are most actively growing and reproducing. This suggests that unfavourable water availability during these two species growth periods limit their distributions along the coast. In addition to unfavourable water deficits, additional climatic variables that may be important in limiting the distribution of these two species were investigated using a discriminant function analysis.
- Full Text:
- Date Issued: 2000
- Authors: Peter, Craig Ingram
- Date: 2000
- Subjects: Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4219 , http://hdl.handle.net/10962/d1003788 , Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Description: Phenomenological models are presented which predicts transpiration rates (E) of individual leaves of Scaevola plumieri, an indigenous dune pioneer, and Ammophila arenaria, an exotic grass species introduced to stabilise mobile sand. In both cases E is predictably related to atmospheric vapour pressure deficit (VPD). VPD is calculated from measurements of ambient temperature and humidity, hence, where these two environmental variables are known, E can be calculated. Possible physiological reasons for the relationships of E to VPD in both species are discussed. Scaling from measurements of E at the leaf level to the canopy level is achieved by summing the leaf area of the canopy in question. E is predicted for the entire canopy leaf area by extrapolation to this larger leaf area. Predicted transpiration rates of individual shoot within the canopy were tested gravimetrically and shown to be accurate in the case of S. plumieri, but less so in the case of A. arenaria. Using this model, the amount of water used by a known area of sand dune is shown to be less than the rainfall input in the case of S. plumieri in wet and dry years. The water use of A. arenaria exceeds rainfall in the low-rainfall year of 1995, while in 1998 rainfall input is slightly higher than water extraction by the plants. Using a geographic information system (GIS), regional maps (surfaces) of transpiration were calculated from surfaces of mean monthly temperature and mean monthly relative humidity. Monthly surfaces of transpiration were subtracted from the monthly median rainfall to produce a surface of mean monthly water deficit. Areas of water surpluses along the coast correspond with the recorded distribution of both species in the seasons that the plants are most actively growing and reproducing. This suggests that unfavourable water availability during these two species growth periods limit their distributions along the coast. In addition to unfavourable water deficits, additional climatic variables that may be important in limiting the distribution of these two species were investigated using a discriminant function analysis.
- Full Text:
- Date Issued: 2000
Water quality, biomass and extracellular polymeric substances in an integrated algae pond system
- Authors: Jimoh, Taobat Adekilekun
- Date: 2018
- Subjects: Water -- Purification , Sewage -- Purification -- Anaerobic treatment , Sewage lagoons , Sewage disposal plants , ASPAM model (Acid mine drainage) , Integrated algae pond systems (IAPS)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/57307 , vital:26871
- Description: Integrated algae pond systems (IAPS) combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. Although, IAPS as a technology process offers many advantages including efficient and simultaneous N and P removal, no requirement for additional chemicals, O2 generation, CO2 mitigation, and a biomass with potential for valorization, a lack of technological advancement and the need for large land area, has limited the reach of this technology at industrial scale. In mitigation, peroxonation was introduced as a tertiary treatment unit and its effect on COD and TSS of IAPS treated water investigated. An effort was made to characterize the soluble but persistent COD in IAPS treated water and, productivity of the HRAOP mixed liquor was investigated to gain insight into the potential use of this biomass. Results show that peroxone treatment effectively reduced COD, TSS, and nutrient load of IAPS water without any significant impact on land area requirement. Indeed, summary data describing the effect of peroxone on quality of IAPS-treated water confirmed that it complies with the general limit values for either irrigation or discharge into a water resource that is not a listed water resource for volumes up to 2 ML of treated wastewater on any given day. Extraction followed by FT-IR spectroscopy was used to confirm albeit tentatively, the identity of the soluble but persistent COD in IAPS treated water as MaB-floc EPS. Results show that MaB-flocs from HRAOPs are assemblages of microorganisms produced as discrete aggregates as a result of microbial EPS production. A relationship between photosynthesis and EPS production was established by quantification of the EPS following exposure of MaB-flocs to either continuous light or darkness. Several novel strains of bacteria were isolated from HRAOP mixed liquor and 16S ribosomal genomic sequence analysis resulted in the molecular characterization of Planococcus maitriensis strain ECCN 45b. This is the first report of Planococcus maitriensis from a wastewater treatment process. Productivity and change in MaB-flocs concentration, measured as mixed liquor suspended solids (MLSS) between morning and evening were monitored and revealed that MLSS is composed of microalgae and bacteria but not fungi. Concentration varied from 77 mg L-1 in September (winter) to 285 mg L-1 in November (spring); pond productivity increased from 5.8 g m-2 d-1 (winter) to 21.5 g m-2 d-1 (spring); and, irrespective of MLSS concentration in late afternoon, approximately 39% was lost overnight, which presumably occurred due to passive removal by the algae settling pond. The outcomes of this research are discussed in terms of the quality of treated water, and the further development of IAPS as a platform technology for establishing a biorefinery within the wastewater treatment sector.
- Full Text:
- Date Issued: 2018
- Authors: Jimoh, Taobat Adekilekun
- Date: 2018
- Subjects: Water -- Purification , Sewage -- Purification -- Anaerobic treatment , Sewage lagoons , Sewage disposal plants , ASPAM model (Acid mine drainage) , Integrated algae pond systems (IAPS)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/57307 , vital:26871
- Description: Integrated algae pond systems (IAPS) combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. Although, IAPS as a technology process offers many advantages including efficient and simultaneous N and P removal, no requirement for additional chemicals, O2 generation, CO2 mitigation, and a biomass with potential for valorization, a lack of technological advancement and the need for large land area, has limited the reach of this technology at industrial scale. In mitigation, peroxonation was introduced as a tertiary treatment unit and its effect on COD and TSS of IAPS treated water investigated. An effort was made to characterize the soluble but persistent COD in IAPS treated water and, productivity of the HRAOP mixed liquor was investigated to gain insight into the potential use of this biomass. Results show that peroxone treatment effectively reduced COD, TSS, and nutrient load of IAPS water without any significant impact on land area requirement. Indeed, summary data describing the effect of peroxone on quality of IAPS-treated water confirmed that it complies with the general limit values for either irrigation or discharge into a water resource that is not a listed water resource for volumes up to 2 ML of treated wastewater on any given day. Extraction followed by FT-IR spectroscopy was used to confirm albeit tentatively, the identity of the soluble but persistent COD in IAPS treated water as MaB-floc EPS. Results show that MaB-flocs from HRAOPs are assemblages of microorganisms produced as discrete aggregates as a result of microbial EPS production. A relationship between photosynthesis and EPS production was established by quantification of the EPS following exposure of MaB-flocs to either continuous light or darkness. Several novel strains of bacteria were isolated from HRAOP mixed liquor and 16S ribosomal genomic sequence analysis resulted in the molecular characterization of Planococcus maitriensis strain ECCN 45b. This is the first report of Planococcus maitriensis from a wastewater treatment process. Productivity and change in MaB-flocs concentration, measured as mixed liquor suspended solids (MLSS) between morning and evening were monitored and revealed that MLSS is composed of microalgae and bacteria but not fungi. Concentration varied from 77 mg L-1 in September (winter) to 285 mg L-1 in November (spring); pond productivity increased from 5.8 g m-2 d-1 (winter) to 21.5 g m-2 d-1 (spring); and, irrespective of MLSS concentration in late afternoon, approximately 39% was lost overnight, which presumably occurred due to passive removal by the algae settling pond. The outcomes of this research are discussed in terms of the quality of treated water, and the further development of IAPS as a platform technology for establishing a biorefinery within the wastewater treatment sector.
- Full Text:
- Date Issued: 2018
Water quality, abalone growth and the potential for integrated mariculture on a South African abalone Haliotis midae L. farm
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
Water quality dynamics in an experimental serial-use raceway and its effects on growth of South African abalone, Haliotis midae
- Authors: Naylor, Matthew Aubrey
- Date: 2012
- Subjects: Haliotis midae -- South Africa , Abalone culture -- South Africa , Abalones -- Effect of water quality on , Abalones -- Nutrition -- South Africa , Abalones -- Feeding and feeds , Abalones -- Growth , Fish culture -- Water reuse
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5335 , http://hdl.handle.net/10962/d1005181 , Haliotis midae -- South Africa , Abalone culture -- South Africa , Abalones -- Effect of water quality on , Abalones -- Nutrition -- South Africa , Abalones -- Feeding and feeds , Abalones -- Growth , Fish culture -- Water reuse
- Description: An understanding of species specific water quality requirements is essential for efficient production of aquaculture products, an aspect not well documented for the land-based culture of the South African abalone, Haliotis midae. In order for the industry to remain competitive in international markets, efficient use of water supplies and the development of water reuse technology is needed. This study assessed the changes in water quality between tanks in a tiered serial-use raceway in relation to accumulated biomass and water flow and estimated the flow index (FI) (L h⁻¹ kg⁻¹) at which growth becomes significantly affected. The effect of dietary protein level, supplementation of pure oxygen and addition of sodium hydroxide (NaOH⁻) on water quality and fundamental production parameters in the serial-use raceways was also assessed. The serial-use raceways were used as a tool to create a range of water quality conditions at which the growth, feed conversion ratio (FCR) and condition factor (CF) of "cocktail" size (60 – 70 mm) H. midae could be monitored. The metabolic activity of the abalone resulted in a deterioration in water quality between tanks in series. pH (r² = 0.99; p < 0.001) and dissolved oxygen concentration (r² = 0.99; p < 0.001) were positively correlated with flow index (pH = 7.38 FI°·°² ; dissolved oxygen = 6.92 FI°·°⁴), while free ammonia nitrogen (FAN) (r² = 0.99, p < 0.001) and nitrite (NO²⁻ - N) (r² = 0.93, p < 0.001) were negatively correlated with flow index (FAN = 8.02 FI⁻°·⁷¹). Nitrite concentrations increased over time indicating colonisation of Nitrosomonas bacteria on the basket surfaces. A flow index of 7.2 – 9.0 L h⁻¹ kg⁻¹ was estimated as the minimum to avoid significant reductions in weight and shell length gain and increases in FCR values. Total ammonia nitrogen (TAN) and FAN concentrations were significantly correlated to dietary protein (P) (t = 6.63, p < 0.0001 and t = 6.41, p < 0.0001, respectively) and flow index (t = 5.42, p < 0.0001 and t = 3.9, p < 0.0002, respectively) and could be estimated using the models TAN = 9.73 P – 110.3 log (FI), and FAN = 0.132 P – 1.10 log (FI). Mean FAN concentrations were 67 and 41 % lower in tanks fed a diet containing 22 and 26 % protein respectively, when compared to tanks fed a 33 % protein diet. Supplementation with pure oxygen (103 ± 8 % saturation) improved shell length gain (t = 3.45, p = 0.026) in abalone exposed to high FAN (2.43 ± 1.1 μg L⁻¹) and low pH (7.6 ± 0.13), relative to a treatment with no oxygen supplementation (92 ± 6 % saturation). Addition of a sodium hydroxide solution resulted in elevated mean pH in treatment raceways when compared to control raceways. The increased pH resulted in significantly higher weight gain (g abalone⁻¹) (F₁·₁₂ = 4.51; p = 0.055) and shell length gain (mm abalone⁻¹) (F₁·₁₂ = 4.56; p = 0.054) at an α-error level of < 5.5 %. In two trials, weight gain and shell length gain were significantly correlated to pH (p < 0.001), and multiple regression of pH, dissolved oxygen and FAN consistently revealed pH to be the best predictor of growth. It is therefore suggested that decreasing pH is the first limiting water quality variable for abalone in serial-use raceways. As a decrease in water pH is linked to respiration by the abalone and subsequent increase in dissolved carbon dioxide (CO₂) concentration, future studies should examine the effects of CO₂ on H. midae metabolic rate, calcification rate and health. The results of this study will contribute toward our understanding of the specific water quality requirements for H. midae in commercial aquaculture systems, and influence the design and management procedures for abalone water reuse systems.
- Full Text:
- Date Issued: 2012
- Authors: Naylor, Matthew Aubrey
- Date: 2012
- Subjects: Haliotis midae -- South Africa , Abalone culture -- South Africa , Abalones -- Effect of water quality on , Abalones -- Nutrition -- South Africa , Abalones -- Feeding and feeds , Abalones -- Growth , Fish culture -- Water reuse
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5335 , http://hdl.handle.net/10962/d1005181 , Haliotis midae -- South Africa , Abalone culture -- South Africa , Abalones -- Effect of water quality on , Abalones -- Nutrition -- South Africa , Abalones -- Feeding and feeds , Abalones -- Growth , Fish culture -- Water reuse
- Description: An understanding of species specific water quality requirements is essential for efficient production of aquaculture products, an aspect not well documented for the land-based culture of the South African abalone, Haliotis midae. In order for the industry to remain competitive in international markets, efficient use of water supplies and the development of water reuse technology is needed. This study assessed the changes in water quality between tanks in a tiered serial-use raceway in relation to accumulated biomass and water flow and estimated the flow index (FI) (L h⁻¹ kg⁻¹) at which growth becomes significantly affected. The effect of dietary protein level, supplementation of pure oxygen and addition of sodium hydroxide (NaOH⁻) on water quality and fundamental production parameters in the serial-use raceways was also assessed. The serial-use raceways were used as a tool to create a range of water quality conditions at which the growth, feed conversion ratio (FCR) and condition factor (CF) of "cocktail" size (60 – 70 mm) H. midae could be monitored. The metabolic activity of the abalone resulted in a deterioration in water quality between tanks in series. pH (r² = 0.99; p < 0.001) and dissolved oxygen concentration (r² = 0.99; p < 0.001) were positively correlated with flow index (pH = 7.38 FI°·°² ; dissolved oxygen = 6.92 FI°·°⁴), while free ammonia nitrogen (FAN) (r² = 0.99, p < 0.001) and nitrite (NO²⁻ - N) (r² = 0.93, p < 0.001) were negatively correlated with flow index (FAN = 8.02 FI⁻°·⁷¹). Nitrite concentrations increased over time indicating colonisation of Nitrosomonas bacteria on the basket surfaces. A flow index of 7.2 – 9.0 L h⁻¹ kg⁻¹ was estimated as the minimum to avoid significant reductions in weight and shell length gain and increases in FCR values. Total ammonia nitrogen (TAN) and FAN concentrations were significantly correlated to dietary protein (P) (t = 6.63, p < 0.0001 and t = 6.41, p < 0.0001, respectively) and flow index (t = 5.42, p < 0.0001 and t = 3.9, p < 0.0002, respectively) and could be estimated using the models TAN = 9.73 P – 110.3 log (FI), and FAN = 0.132 P – 1.10 log (FI). Mean FAN concentrations were 67 and 41 % lower in tanks fed a diet containing 22 and 26 % protein respectively, when compared to tanks fed a 33 % protein diet. Supplementation with pure oxygen (103 ± 8 % saturation) improved shell length gain (t = 3.45, p = 0.026) in abalone exposed to high FAN (2.43 ± 1.1 μg L⁻¹) and low pH (7.6 ± 0.13), relative to a treatment with no oxygen supplementation (92 ± 6 % saturation). Addition of a sodium hydroxide solution resulted in elevated mean pH in treatment raceways when compared to control raceways. The increased pH resulted in significantly higher weight gain (g abalone⁻¹) (F₁·₁₂ = 4.51; p = 0.055) and shell length gain (mm abalone⁻¹) (F₁·₁₂ = 4.56; p = 0.054) at an α-error level of < 5.5 %. In two trials, weight gain and shell length gain were significantly correlated to pH (p < 0.001), and multiple regression of pH, dissolved oxygen and FAN consistently revealed pH to be the best predictor of growth. It is therefore suggested that decreasing pH is the first limiting water quality variable for abalone in serial-use raceways. As a decrease in water pH is linked to respiration by the abalone and subsequent increase in dissolved carbon dioxide (CO₂) concentration, future studies should examine the effects of CO₂ on H. midae metabolic rate, calcification rate and health. The results of this study will contribute toward our understanding of the specific water quality requirements for H. midae in commercial aquaculture systems, and influence the design and management procedures for abalone water reuse systems.
- Full Text:
- Date Issued: 2012
Water footprint of growing vegetables in selected smallholder irrigation schemes in South Africa
- Authors: Nyambo, Patrick
- Date: 2014
- Subjects: Water consumption , Irrigation efficiency , Rural development
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11964 , http://hdl.handle.net/10353/d1019775 , Water consumption , Irrigation efficiency , Rural development
- Description: Knowledge of water use, through water foot printing (WF) in smallholder agriculture crop production is the key to the global fight against poverty, achievement of food security and sustainability within the world’s rural community. Water footprint of a crop can be defined as the volume of fresh water used to produce a certain crop in all the steps in the production line. This study, therefore aimed at contributing towards improvements in rural livelihoods by raising awareness of the increased productive use of green, blue and grey water in smallholder agriculture in South Africa. This was done through determination of water footprints of five vegetable crops, i.e. potatoes (Solanum tuberosum), tomatoes (Solanum lycopersicum), dry beans (Phaseolus vulgaris), cabbage (Brassica oleracea spp) and spinach (Spinacia oleracea) in the 2000-2013 period. Quantification of water footprints has been done worldwide but, in South Africa (SA) focus has mostly been on the industrial and domestic sector. Water footprint assessment framework, was used to estimate the full impact of vegetable production on water resources at Zanyokwe, Thabina and Tugela Ferry irrigation schemes as case studies. The CROPWAT@ model was used to calculate crop evapotranspiration, differentiating green and blue water. Local climatic data were obtained from SA weather services, while the crop and soil parameters were obtained from the FAO data base. Nitrogen was considered the main pollutant hence its use in the grey water footprint calculation. Generally, Thabina irrigation scheme had the highest water footprint, followed by Tugela Ferry irrigation scheme whilst Zanyokwe irrigation scheme had the lowest. Green beans had the highest water footprint at all the three irrigation schemes with Thabina irrigation scheme having the highest (3535.1 m3/ton). For Tugela Ferry irrigation scheme, the calculated WF was 2753 m3/ton whilst the lowest was observed at ZIS i.e. 2407.6 m3/ton. Cabbage had the lowest water footprint. The highest water footprint for growing cabbage was 254.5 m3/ton in TFIS, 223.1 m3/ton in TIS and the lowest was 217.8 m3/ton in ZIS. The differences observed in the WF of a crop at each scheme maybe attributed to the differences management, weather and environmental characteristics, in the three locations. Moreover, the needs for ET are related to soil type and plant growth, and primarily depend on crop development and climatic factors which are closely related to climatic demands. The grey water footprint was calculated using the recommended fertilizer application rates for all the three sites. Green beans had the highest WFgrey i.e. 373 m3/ton and the lowest was cabbage with 37 m3/ton. Potato, spinach and tomatoes had 156 m3/ton, 214 m3/ton and 132 m3/ton, respectively. Grey water footprint in this study was higher as compared to other studies, possibly because of the high rates of nitrogen fertilizers used in the calculations and the low yields farmers get. Compared with estimates from other studies, the water footprints of vegetable production within smallholder irrigation schemes was relatively high. There is therefore, a need to focus on crop management and tillage practices that will help in increasing yield while minimizing water usage.
- Full Text:
- Date Issued: 2014
- Authors: Nyambo, Patrick
- Date: 2014
- Subjects: Water consumption , Irrigation efficiency , Rural development
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11964 , http://hdl.handle.net/10353/d1019775 , Water consumption , Irrigation efficiency , Rural development
- Description: Knowledge of water use, through water foot printing (WF) in smallholder agriculture crop production is the key to the global fight against poverty, achievement of food security and sustainability within the world’s rural community. Water footprint of a crop can be defined as the volume of fresh water used to produce a certain crop in all the steps in the production line. This study, therefore aimed at contributing towards improvements in rural livelihoods by raising awareness of the increased productive use of green, blue and grey water in smallholder agriculture in South Africa. This was done through determination of water footprints of five vegetable crops, i.e. potatoes (Solanum tuberosum), tomatoes (Solanum lycopersicum), dry beans (Phaseolus vulgaris), cabbage (Brassica oleracea spp) and spinach (Spinacia oleracea) in the 2000-2013 period. Quantification of water footprints has been done worldwide but, in South Africa (SA) focus has mostly been on the industrial and domestic sector. Water footprint assessment framework, was used to estimate the full impact of vegetable production on water resources at Zanyokwe, Thabina and Tugela Ferry irrigation schemes as case studies. The CROPWAT@ model was used to calculate crop evapotranspiration, differentiating green and blue water. Local climatic data were obtained from SA weather services, while the crop and soil parameters were obtained from the FAO data base. Nitrogen was considered the main pollutant hence its use in the grey water footprint calculation. Generally, Thabina irrigation scheme had the highest water footprint, followed by Tugela Ferry irrigation scheme whilst Zanyokwe irrigation scheme had the lowest. Green beans had the highest water footprint at all the three irrigation schemes with Thabina irrigation scheme having the highest (3535.1 m3/ton). For Tugela Ferry irrigation scheme, the calculated WF was 2753 m3/ton whilst the lowest was observed at ZIS i.e. 2407.6 m3/ton. Cabbage had the lowest water footprint. The highest water footprint for growing cabbage was 254.5 m3/ton in TFIS, 223.1 m3/ton in TIS and the lowest was 217.8 m3/ton in ZIS. The differences observed in the WF of a crop at each scheme maybe attributed to the differences management, weather and environmental characteristics, in the three locations. Moreover, the needs for ET are related to soil type and plant growth, and primarily depend on crop development and climatic factors which are closely related to climatic demands. The grey water footprint was calculated using the recommended fertilizer application rates for all the three sites. Green beans had the highest WFgrey i.e. 373 m3/ton and the lowest was cabbage with 37 m3/ton. Potato, spinach and tomatoes had 156 m3/ton, 214 m3/ton and 132 m3/ton, respectively. Grey water footprint in this study was higher as compared to other studies, possibly because of the high rates of nitrogen fertilizers used in the calculations and the low yields farmers get. Compared with estimates from other studies, the water footprints of vegetable production within smallholder irrigation schemes was relatively high. There is therefore, a need to focus on crop management and tillage practices that will help in increasing yield while minimizing water usage.
- Full Text:
- Date Issued: 2014
Water footprint and economic water productivity of citrus production: a comparison across three river valleys in the Eastern Cape Milands
- Authors: Danckwerts, Lindsay
- Date: 2020
- Subjects: Water in agriculture -- South Africa -- Eastern Cape , Water consumption -- South Africa -- Economic aspects , Water supply, Agricultural -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141064 , vital:37941
- Description: South Africa is a semi-arid, water scarce country. The nation has suffered a spate of severe droughts in several regions in recent years, which have significantly impacted the country’s economy. Global warming, population growth, and rising demand for water intensive products are only expected to intensify water supply problems in the future. The agricultural industry is the largest consumer of water in South Africa, accounting for the majority of total surface water withdrawals. As such, the agricultural sector is faced with complex and difficult management decisions in the face of a potential water supply crisis. The water footprint (WF) and economic water productivity (EWP) of citrus production across three river catchments located in the Eastern Cape Midlands (situated in the vicinity of the settlements of Adelaide, Cookhouse and Fort Beaufort respectively) were calculated and compared. In the long-term average (LTA), blue WF weighted across all three regions accounted for the greatest proportion of total WF (53%), followed in turn by green and grey WF (30% and 17% respectively). LTA blue and grey WF was lowest in the Adelaide region, while green WF was smallest in the Fort Beaufort region. Blue, green and grey WF were found to be greatest in the Cookhouse region. LTA EWP was greatest in the Fort Beaufort region and smallest in the Adelaide region. Of all variety groups assessed, lemons were found to have the lowest LTA crop water use and blue, green and grey WF when considering citrus production averaged across all three study regions. Satsumas has the second smallest LTA blue, green and grey WF, followed by navels, mid-season mandarins, and finally, late mandarins. Lemons had the greatest LTA EWP of all varieties, followed in turn by satsumas, late mandarins, mid-season mandarins and navels. Blue crop water use was consistently lowest in the designated wet year and highest in the dry year. However, this same trend was not necessarily true for WF findings. WF and EWP are useful indicators of water use which can be used to help guide complex water management decisions. However, these indicators are single-factor productivity measures applied in a multi-factor environment. It is therefore important that factors outside of water use are considered when making water management decisions. Moreover, it is important to examine the impact that the various components making up WF and EWP have on the resultant figures, rather than merely considering the superficial results themselves. Factors such as CWU, orchard maturity, crop choice, potential yield, climate, irrigation system, economic return, water allocation and water availability should all be taken into account.
- Full Text:
- Date Issued: 2020
- Authors: Danckwerts, Lindsay
- Date: 2020
- Subjects: Water in agriculture -- South Africa -- Eastern Cape , Water consumption -- South Africa -- Economic aspects , Water supply, Agricultural -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141064 , vital:37941
- Description: South Africa is a semi-arid, water scarce country. The nation has suffered a spate of severe droughts in several regions in recent years, which have significantly impacted the country’s economy. Global warming, population growth, and rising demand for water intensive products are only expected to intensify water supply problems in the future. The agricultural industry is the largest consumer of water in South Africa, accounting for the majority of total surface water withdrawals. As such, the agricultural sector is faced with complex and difficult management decisions in the face of a potential water supply crisis. The water footprint (WF) and economic water productivity (EWP) of citrus production across three river catchments located in the Eastern Cape Midlands (situated in the vicinity of the settlements of Adelaide, Cookhouse and Fort Beaufort respectively) were calculated and compared. In the long-term average (LTA), blue WF weighted across all three regions accounted for the greatest proportion of total WF (53%), followed in turn by green and grey WF (30% and 17% respectively). LTA blue and grey WF was lowest in the Adelaide region, while green WF was smallest in the Fort Beaufort region. Blue, green and grey WF were found to be greatest in the Cookhouse region. LTA EWP was greatest in the Fort Beaufort region and smallest in the Adelaide region. Of all variety groups assessed, lemons were found to have the lowest LTA crop water use and blue, green and grey WF when considering citrus production averaged across all three study regions. Satsumas has the second smallest LTA blue, green and grey WF, followed by navels, mid-season mandarins, and finally, late mandarins. Lemons had the greatest LTA EWP of all varieties, followed in turn by satsumas, late mandarins, mid-season mandarins and navels. Blue crop water use was consistently lowest in the designated wet year and highest in the dry year. However, this same trend was not necessarily true for WF findings. WF and EWP are useful indicators of water use which can be used to help guide complex water management decisions. However, these indicators are single-factor productivity measures applied in a multi-factor environment. It is therefore important that factors outside of water use are considered when making water management decisions. Moreover, it is important to examine the impact that the various components making up WF and EWP have on the resultant figures, rather than merely considering the superficial results themselves. Factors such as CWU, orchard maturity, crop choice, potential yield, climate, irrigation system, economic return, water allocation and water availability should all be taken into account.
- Full Text:
- Date Issued: 2020
Water conservation and water demand management in Buffalo City Metropolitan Municipality
- Authors: Mlomzale, Kwanele
- Date: 2021-04
- Subjects: Water conservation -- South Africa -- Buffalo City , Water demand management -- South Africa -- Buffalo City , Municipal services -- South Africa -- Buffalo City , Municipal services -- Law and legislation -- South Africa -- Buffalo City , Water-supply -- Management
- Language: English
- Type: thesis , text , Masters , MBA
- Identifier: http://hdl.handle.net/10962/177159 , vital:42795
- Description: Water is one of the scarce and constrained natural resource globally, and a necessity to every living creature, organism and the natural environment – it is the existence of life. Water, as an irreplaceable natural resource, plays a vital role in every country's development and prosperity, integrating socio-economic needs of both the present and future generation. Therefore, sustainable strategies and approaches or concepts are significant in ensuring that such a unique resource is preserved and conserved sustainably. Municipal environment or local government sphere creates a pivotal role in governing the use of water, through the provision of legislation, regulations and establishment of water conservation and water demand management strategies and plans. However, it has been established that there is a lack of integrated water resource management approach and planning in municipalities, creating concerns with regards to controlling the overutilisation of water and protection of water sources in general. The aim and goals of the study are to review Buffalo City Metropolitan Municipality's (BCMM) water conservation and water demand management (BCMM WC/WDM) development and implementation by, assessing the existing strategy related to water conservation and water demand management; constraints and opportunity identification; and provision of recommendations in improving the practices in the municipality. The study presents core theories and empirical studies relevant to the water conservation and water demand management, and also deals with theoretical framework found under the Natural Resource-Based View and its application to water conservation and water demand management concepts. A qualitative research design approach was used for the research, which is underpinned by a post-positivism paradigm. In terms of data collection, two methods were used in the study: (i) document study and secondary analysis; and (ii) semi-structured interviews with BCMM relevant officials. The study identified gaps and inconsistencies in the development and implementation of BCMM WC/WDM strategy, although the municipality has taken some step towards its implementation. However, the strives taken by BCMM in implementing water conservation and water demand management initiatives are acknowledged. The study provides recommendations related to the findings identified upon the data collection and fieldwork. The recommendation proposed by the study includes proper communicating the BCMM WC/WDM strategy to all relevant stakeholders, focus on reducing the non-revenue water, implementation of various project related to pressure management, encourage culture of using water efficiently through educational and community awareness campaigns, capacitation of BCMM including seeking financial support, continuous review of the strategy and exploring other water supply sources to relax the already constrained existing water sources. The limitations of the study compared to the broader scope of water conservation and water demand management aspects are highlighted and acknowledged. Thus, in the conclusion of this study, further future studies are suggested to explore other related aspects of water conservation and water demand management in BCMM. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mlomzale, Kwanele
- Date: 2021-04
- Subjects: Water conservation -- South Africa -- Buffalo City , Water demand management -- South Africa -- Buffalo City , Municipal services -- South Africa -- Buffalo City , Municipal services -- Law and legislation -- South Africa -- Buffalo City , Water-supply -- Management
- Language: English
- Type: thesis , text , Masters , MBA
- Identifier: http://hdl.handle.net/10962/177159 , vital:42795
- Description: Water is one of the scarce and constrained natural resource globally, and a necessity to every living creature, organism and the natural environment – it is the existence of life. Water, as an irreplaceable natural resource, plays a vital role in every country's development and prosperity, integrating socio-economic needs of both the present and future generation. Therefore, sustainable strategies and approaches or concepts are significant in ensuring that such a unique resource is preserved and conserved sustainably. Municipal environment or local government sphere creates a pivotal role in governing the use of water, through the provision of legislation, regulations and establishment of water conservation and water demand management strategies and plans. However, it has been established that there is a lack of integrated water resource management approach and planning in municipalities, creating concerns with regards to controlling the overutilisation of water and protection of water sources in general. The aim and goals of the study are to review Buffalo City Metropolitan Municipality's (BCMM) water conservation and water demand management (BCMM WC/WDM) development and implementation by, assessing the existing strategy related to water conservation and water demand management; constraints and opportunity identification; and provision of recommendations in improving the practices in the municipality. The study presents core theories and empirical studies relevant to the water conservation and water demand management, and also deals with theoretical framework found under the Natural Resource-Based View and its application to water conservation and water demand management concepts. A qualitative research design approach was used for the research, which is underpinned by a post-positivism paradigm. In terms of data collection, two methods were used in the study: (i) document study and secondary analysis; and (ii) semi-structured interviews with BCMM relevant officials. The study identified gaps and inconsistencies in the development and implementation of BCMM WC/WDM strategy, although the municipality has taken some step towards its implementation. However, the strives taken by BCMM in implementing water conservation and water demand management initiatives are acknowledged. The study provides recommendations related to the findings identified upon the data collection and fieldwork. The recommendation proposed by the study includes proper communicating the BCMM WC/WDM strategy to all relevant stakeholders, focus on reducing the non-revenue water, implementation of various project related to pressure management, encourage culture of using water efficiently through educational and community awareness campaigns, capacitation of BCMM including seeking financial support, continuous review of the strategy and exploring other water supply sources to relax the already constrained existing water sources. The limitations of the study compared to the broader scope of water conservation and water demand management aspects are highlighted and acknowledged. Thus, in the conclusion of this study, further future studies are suggested to explore other related aspects of water conservation and water demand management in BCMM. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
- Full Text:
- Date Issued: 2021-04
Waste services provided by community-based enterprises in the Ngombe Peri-Urban settlement area, Lusaka, Zambia
- Authors: Maninga, Mainess Kapaipi
- Date: 2012
- Subjects: Refuse disposal industry , Recycling (Waste, etc.) -- Economic aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9835 , http://hdl.handle.net/10948/d1011560 , Refuse disposal industry , Recycling (Waste, etc.) -- Economic aspects
- Description: This qualitative study investigates Waste services provided by community-based enterprises in the Ngombe peri-urban settlement area - Lusaka, Zambia. The aim of the study was to identify and analyze the factors that contribute to illegal dumping of solid waste in the said peri-urban settlement area. The research objectives were as follows: To explore the capability of the community-based enterprises to effectively manage their enterprises in relation to the provision of solid waste services to the residents of the said settlement, To identify and evaluate the solid waste services provided by the community-based enterprises, and To make recommendations for the improvement of solid waste service provision and utilisation based on the findings of the study. The method of data collection for the above listed objectives was a literature study and focus group interviews. In order to achieve the said objectives of the study, the researcher opted for a qualitative research design – utilizing the contextual, descriptive, inductive and deductive approaches. The research population comprised the community-based enterprises involved in the provision of solid waste services in the Ngombe settlement area namely Kutwano and Tiyende Pamodzi Waste Enterprises. The purposive sample method was used for the selection of the focus group. The focus group discussions were captured by means of an audiotape and note-taking. The interviews were transcribed verbatim, within 24 hours of data capturing. Data analysis followed the five steps of Powell and Renner (2003, pp,1-6), namely: familiarization, identifying a thematic framework, categorization (coding or indexing) of data, identifying patterns and connections within and between categories (relationships), and interpretation (bringing it all together). The researcher adhered to the relevant ethical considerations and the principles of trustworthiness, namely: credibility, transferability, dependability and conformability throughout the study. In exploring the capability of the two community-based enterprises to effectively manage their enterprises in relation to the provision of solid waste services to the residents of the said settlement it was found that community-based enterprises do not have the capability to provide adequate solid waste services. This is due to inadequate leadership and entrepreneurship skills of the community-based enterprises management committee members, non-payment of solid waste collection fees by the majority of households and inadequate legal enforcement by the Lusaka City Council’s Waste Management Unit. In identifying and evaluating the solid waste services provided by the community-based enterprises it was found that solid waste services provided by community-based enterprises were inadequate. This is due to the type of equipment (push carts) used for primary solid waste collection that does not carter for other forms of solid waste like construction waste; inappropriate solid waste storage containers (25kg maize meal bags) which do not allow storage of solid waste in a sanitary manner (non-leak proof, accessible to rats, flies and cockroaches and rodents); restriction on the type of solid waste that community-based enterprises should collect (in relation to the specified solid waste storage container, 25kg maize meal bags) and the delay of secondary solid waste collection by Lusaka City Council’s Waste Management Unit. On the basis of the findings of the study, a number of recommendations are being made, which, if implemented effectively, should improve the provision and utilisation of solid waste services within the study area. Such an improvement should lead to a higher level of environmental cleanliness, and ultimately to better health standards of the people living within the area.
- Full Text:
- Authors: Maninga, Mainess Kapaipi
- Date: 2012
- Subjects: Refuse disposal industry , Recycling (Waste, etc.) -- Economic aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9835 , http://hdl.handle.net/10948/d1011560 , Refuse disposal industry , Recycling (Waste, etc.) -- Economic aspects
- Description: This qualitative study investigates Waste services provided by community-based enterprises in the Ngombe peri-urban settlement area - Lusaka, Zambia. The aim of the study was to identify and analyze the factors that contribute to illegal dumping of solid waste in the said peri-urban settlement area. The research objectives were as follows: To explore the capability of the community-based enterprises to effectively manage their enterprises in relation to the provision of solid waste services to the residents of the said settlement, To identify and evaluate the solid waste services provided by the community-based enterprises, and To make recommendations for the improvement of solid waste service provision and utilisation based on the findings of the study. The method of data collection for the above listed objectives was a literature study and focus group interviews. In order to achieve the said objectives of the study, the researcher opted for a qualitative research design – utilizing the contextual, descriptive, inductive and deductive approaches. The research population comprised the community-based enterprises involved in the provision of solid waste services in the Ngombe settlement area namely Kutwano and Tiyende Pamodzi Waste Enterprises. The purposive sample method was used for the selection of the focus group. The focus group discussions were captured by means of an audiotape and note-taking. The interviews were transcribed verbatim, within 24 hours of data capturing. Data analysis followed the five steps of Powell and Renner (2003, pp,1-6), namely: familiarization, identifying a thematic framework, categorization (coding or indexing) of data, identifying patterns and connections within and between categories (relationships), and interpretation (bringing it all together). The researcher adhered to the relevant ethical considerations and the principles of trustworthiness, namely: credibility, transferability, dependability and conformability throughout the study. In exploring the capability of the two community-based enterprises to effectively manage their enterprises in relation to the provision of solid waste services to the residents of the said settlement it was found that community-based enterprises do not have the capability to provide adequate solid waste services. This is due to inadequate leadership and entrepreneurship skills of the community-based enterprises management committee members, non-payment of solid waste collection fees by the majority of households and inadequate legal enforcement by the Lusaka City Council’s Waste Management Unit. In identifying and evaluating the solid waste services provided by the community-based enterprises it was found that solid waste services provided by community-based enterprises were inadequate. This is due to the type of equipment (push carts) used for primary solid waste collection that does not carter for other forms of solid waste like construction waste; inappropriate solid waste storage containers (25kg maize meal bags) which do not allow storage of solid waste in a sanitary manner (non-leak proof, accessible to rats, flies and cockroaches and rodents); restriction on the type of solid waste that community-based enterprises should collect (in relation to the specified solid waste storage container, 25kg maize meal bags) and the delay of secondary solid waste collection by Lusaka City Council’s Waste Management Unit. On the basis of the findings of the study, a number of recommendations are being made, which, if implemented effectively, should improve the provision and utilisation of solid waste services within the study area. Such an improvement should lead to a higher level of environmental cleanliness, and ultimately to better health standards of the people living within the area.
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