School of Animal, Plant and Environmental Sciences (ETDs)

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Browsing School of Animal, Plant and Environmental Sciences (ETDs) by SDG "SDG-6: Clean water and sanitation"

Now showing 1 - 4 of 4
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    Comparative Analysis of Water Hyacinth Efficiency as Biosorbent and Phyto remediating Plant for Removal of Lead (Pb) Water Contaminants
    (University of the Witwatersrand, Johannesburg, 2023-08) Nwagbara, Victor Uzoma; Parrini, Francesca; Newete, Solomon
    One of the major problems facing the modern society is the issues of water contamination. The ability of aquatic plants to serve as both heavy metal biomarkers and phytoremediators has been advocated for many years. The purpose of this study was therefore to compare the efficacy of water hyacith as a biosorbent and phytoremediating plant for removal of lead from contaminated waters. Dry and fresh water hyacinth biomass were exposed to Pb-contaminated water at different time intervals of 1, 7, 14 and 21 days. The results showed that with the increase of the exposure time, the Pb removal capacity of the plant biomass also increased. The Pb water concentration in day 1 and day 7 were significantly different from those in day 14 and day 21 which were not significantly different from each other. The average Pb removal from the Pb-treated waters for the different time exposure of 1, 7, 14 and 21 days in the fresh water hyacinth biomass were 40%, 56%, 78 % and 79%, respectively, the highest reduction being in the latter. The biomass of the freshwater hyacinth roots had the highest Pd concentration compared to the shoot. On The other hand the average Pb removal by the dry water hyacinth biomass were 78.9 %, 78.5%, 78.3 % and 78.3% for day 1, 7, 14 and 21 respectively, showing no significant difference between the different time series exposure. This suggests the instant adsorption of Pb by the dry plant material from the first day of exposure, after which the active sites for adsorption saturates to accommodate any further Pb ion uptake. There were some plant stresses such as leaf chlorosis, and significant decrease in biomass weight and length of leaf-2 petiole in the lead-treated fresh water hyacinth plants compared to the controls (Pb-free water hyacinth plant). Thus, this study confirms that the largest removal by the dry water hyacinth biomass, occurred in the first day as opposed to the last day (day 21) by the freshwater hyacinth biomass.
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    Evaluating the Effectiveness of Green Drop Audit Criterion in Relation to Its Link to Enforcement Protocol in South Africa
    (University of the Witwatersrand, Johannesburg, 2022-08) Tshongweni, Olwethu Lenox; Tutu, Hlanganani; Richards, Heidi L.
    The Green and Blue Drop programs are incentive-based regulatory systems based on the Department of Water and Sanitation's (DWS) realization that rewarding positive behaviour is more efficient and effective than penalizing undesirable behaviour. The Green Drop was developed for the Wastewater Quality Management Regulation certification program. In contrast, the Blue Drop was developed for the certification program for the Drinking Water Quality Management Regulation (Burgess, 2021). Most municipalities have accepted them and have raised awareness about the need for better efficiency in the wastewater sector. The Sand River, in Polokwane wastewater treatment works (WWTWs), was chosen as the research area for this study. This particular river was selected based on the premise of continuous non-compliance of the wastewater treatment plant and the resulting pressure it puts on the Sand River by compromising its quality, with the DWS not having a successful way of regulating and enforcing the water user to abide by the rules of the license that has been issued. This study aims to evaluate the effectiveness of the Green Drop Program audits and assessments about their link to the regulatory system within the DWS. Additionally, a risk assessment and cumulative risk rating are used to assess wastewater discharge into the Sand River in the Limpopo Province. Based on the observation made during the study, it appears that within the DWS organizational arrangements, the lack of coordination among the sectors (compliance monitoring, water quality management, the green drop program, and enforcement), lack of accountability, and the regulatory requirement of cooperation within DWS sectors have hindered implementation. Some of the non-compliance factors may be due to the misuse of funds meant for infrastructure development and difficulties relating to capacity, procurement, and management of the WWTWs. Moreover, DWS's absence of interactive data management systems and business processes contributes to non-compliance. The Polokwane WWTW, directly linked to the Sand River, is overloaded and needs to comply with the Water Use Licence (WUL) conditions. For example, the 21 August 2022, this facility was found to be non-compliant by 69.01%, collectively with administration and technical conditions of the WUL issued to the facility (DWS, 2022c). In addition, this investigation discovered that the Polokwane facility, which has been operating outside of regulations for the past four years, therefore, as calculated in equation 7 could be responsible for 72.3% of the hazards to people's health, the quality of the river's water, and the aquatic ecosystem life in the Sand River in a single month. As much as some municipalities do not perform according to the desired standards, there have been a few noticeable, well-performing ones reported in the green drop report released in 2022. These include Langebaan WWTW (90%), Riebeek Valley WWTW (97%), Gansevallei WWTW (84%), and Wellington WWTW (95%), and this illustrates that the Green Drop Certification is achievable if the municipalities follow and adhere to the Water Use Authorization (WUA) issued them (DWS, 2022b). The DWS must integrate the internal structures or link sectors responsible for monitoring and regulating municipal water service facilities and incentivize performing facilities to improve their performance. Additionally, facilities with minor compliance issues, such as water quality, must be referred to the Water Quality Management (WQM) unit for further investigation and recommendations. However, those non-compliances of authorized wastewater treatment facilities that require regulatory attention must be referred to the compliance monitoring sector through the system for compliance monitoring. Lastly, those facilities that are not authorized must be directed to enforcement for further action. Therefore, using the Integrated Regulatory Information System (IRIS) as the umbrella body for both database and work-based information has an imperative role that can curb some of the issues faced by the DWS. Standard operating procedures (SOPs) should guide all interactions between these systems.
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    The characterisation of borehole water properties and soil salinity across seasons for the period 2016-2020 with some links to rainfall and sugarcane yield in the Makhathini Irrigation Scheme, KwaZulu-Natal
    (University of the Witwatersrand, Johannesburg, 2024) Ndwamato, Ramabulana Cassius; Scholes, Mary
    The sugar business in South Africa has a strong socioeconomic development focus in rural regions, creating jobs, giving a source of revenue, and constructing transportation and communication networks. Despite its benefits, the sugar sector has faced several obstacles mostly by Small-Scale Growers (SSGs), which have led to a decline in sugarcane production. This study analysed borehole water properties such as electrical conductivity, water levels, and temperature at the Makhathini Irrigation Scheme in KwaZulu-Natal. The quality of water from the Jozini/Pongola Dam used for irrigation was also analysed, in addition to the salinity levels of the soil at the irrigation scheme. Water from nineteen (19) boreholes within the irrigation scheme between 2016 and 2020 was collected every three months from January and tested. Annual water quality data collected upstream (PR1) and downstream (PR2) of the dam were obtained from the Department of Water and Sanitation. One kilogram of soil was collected from six sampling points, respectively, within the Makhathini Irrigation Scheme and sent for testing at the Agricultural Research Council Institute of Soil Water and Climate. Rainfall data and annual sugarcane yield data were obtained and analysed. The ANOVA results showed a significant (p < 0.05) difference in electrical conductivity (EC) between all 19 boreholes in the five-year data. The Tukey test also confirmed the electrical conductivity’s significant (p < 0.05) variation across all boreholes during dry and wet seasons. The borehole water level analysis shows that no significant (p > 0.05) difference was observed in dry seasons, but there was a significant difference in the wet seasons. The Tukey test also confirmed that the borehole water levels varied significantly during the wet season for the five-year study period, suggesting that the water levels were shallow in the wet seasons compared to the dry season. The borehole water temperature analysis indicates no significant (p > 0.05) difference for all seasons from 2016 to 2020. The water collected at PR1 suggests that the water from the dam is of acceptable quality for irrigation, while the return flow to the Pongola River at sampling point PR2 had high SAR, EC, and PO4 - concentrations. Samples collected downstream (PR2) show signs of pollution. This suggests that water contamination occurs when water passes through the Makhathini Irrigation Scheme. A t-test analysis reveals that pH, NO3 - , and NO2 have no significant (p > 0.05) difference, but SAR, EC and PO4 - were significant (p < 0.05). The measured parameters were compared to the Department of Water Affairs and Forestry standards for the quality of water used in agricultural irrigation. The correlation analysis between rainfall, borehole electrical conductivity, borehole water levels, and sugarcane yields revealed that while rainfall influenced borehole electrical conductivity, water levels, and sugarcane yield, the effect was minimal, possibly due to irrigation volumes. Rainfall had a positive effect on sugarcane production and EC but a negative effect on water levels. Soil salinity analysis demonstrated an increase in the soil's electrical conductivity with each passing year. The ANOVA analyses for sugarcane yield and soil salinity reveal statistically significant differences (p < 0.05). The accumulation of salts in the soil at the Makhathini Irrigation Scheme, also seen by the contaminated return flow to the Pongola River, reduces sugarcane yields. Water properties of the sugarcane irrigation water affect the soil salinity in the irrigation scheme and, consequently, the decline in sugarcane production by small-scale growers.
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    Water quality assessment at Vaalkop Dam in North-West Province using multispectral remote sensing data
    (University of the Witwatersrand, Johannesburg, 2022) Mthimkulu, Lindy Ndzumbululo; Adam, Elhadi
    Water is a life-sustaining resource for all organisms. As much as nature share the value of water with human being it cannot supersede how human have become dependent on water for drinking, sanitation, farming, mining, and other industrial purposes such as power generation. Water is perceived as a vital component in the fight against poverty, the foundation of any successfully growing and developed country is also measured on water and sanitation provision (Basson et al., 1997). The water law in South Africa stresses that essential human and ecological necessities must be given (DWAF, 1998) and that the misuse of water from all perspectives should be feasible (New, 2002).