South Africa's wastewater treatment facilities (WWTWs) are facing a growing crisis. According to the Green Drop Progress Assessment report, which served as the baseline for operational planning in 2024, 64% of WWTWs are classified as being in a high or critical risk state. This decline is driven by a mismatch between infrastructure investment, governance capacity, and technological choices, compounded by the failure of most municipalities to produce Wastewater Risk Abatement Plans. A systematic literature review (SLR) of 39 peer-reviewed and grey literature sources was conducted, guided by the PRISMA framework, to analyse South African wastewater services and WWTWs. The findings highlight a crucial trade-off between energy-intensive mechanical systems and resilient nature-based solutions. Additionally, barriers in financing and regulatory enforcement create a gulf between innovation and practical implementation. This paper presents a phased strategic plan: immediate regulatory enforcement to stabilise existing assets; medium-term integration of renewable energy and decentralised systems to enhance resilience; and long-term financial restructuring to attract private-sector investment.
The widespread integration of vacuum toilet technology, observed across diverse sanitation infrastructures such as trains, airplanes, festivals, and residential houses, not only achieves a remarkable 90% reduction in fresh water consumption but also demonstrates true sustainability. In this article, the composition of such vacuum toilet water from rush-hour trains is analysed with respect to its subsequent treatment to meet stringent discharge limits for surface water. Based on this compositional analysis, opportunities for resource recovery of valuable substances (e.g., volatile fatty acids, phosphate, zinc, and silicon) and for biogas production are identified. Conventional pH adjustment was applied to show the potential of valuable mineral recovery (respectively, 50% of calcium, 66% of magnesium, 87% of zinc, 57% of ammonium, 99% of phosphate and 30% of sulphate). Electrocoagulation flotation was explored at a low coagulant/tCOD ratio and proved to be a promising sanitation technology for COD and phosphate removal, at 60% and 69%, respectively.
Sanitation in South Africa faces numerous challenges and new technologies are needed to cater for the country's growing population. One such technology, showing potential in other developing countries, is DEWATS (decentralized wastewater treatment systems). This research investigated the environmental performance and optimisation potential of DEWATS in the local context by employing life cycle assessment (LCA) methodology to 3 possible scenarios. These were defined as (i) a 'typical' flush water system, (ii) a reduced flush water system and (iii) a reduced flush water system with urine separation and struvite production to replace a commercial fertiliser. LCAs were performed and the construction and operation of all three systems were modelled. The SimaPro LCA software was employed and 18 different environmental impacts were evaluated by following the ReCiPe midpoint method. This resulted in an environmental profile for each system enabling comparisons. The water consumed for sanitation is the highest single contributor to environmental burdens in all three systems and reducing the amount of toilet flush water not only saves a scarce resource but also decreased most other environmental burdens. The best overall environmental performance was achieved by the system with reduced flush water and the separation and processing of urine to a fertiliser. The use of rainwater for flushing toilets can lead to further improvements for all three systems. When comparing the burdens of the operation of DEWATS with those of their construction, these decrease with the reduction in water consumption, focusing further potential improvements on the materials used in construction. Therefore, this study shows how LCA can be used for local optimisation of DEWATS and guiding further improvements for these systems.
This study investigated the occurrence and removal of microplastics (MP) in samples collected from the influent and effluent of a municipal wastewater treatment plant and from specific stages of an industrial water treatment plant, including the raw water, clarifier, sand filter, and mixed bed outlet. The wet-peroxide oxidation method was used to isolate the microplastics, and these were characterised by techniques such as stereomicroscopy, scanning electron microscopy (SEM), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) to determine properties such as shape, colour, size and membrane prepared via interfacial polymerisation was used to reject the isolated microplastics. Nylon-6 and polyethylene were found to be the most predominant polymers, which were either blue, black or red in colour. The most common shapes in both sampling areas were primarily fibres (48.5%), fragments (30.3%), and films (21.2%) and the presence of such morphologies was influenced by various anthropogenic activities. Whilst the microplastic abundance ranged from 2.22 +/- 1.11 MP/L to 24.44 +/- 11.50 MP/L. The membranes achieved a rejection efficiency of 97.33% through size exclusion and hydrophilic-hydrophobic interactions. These findings demonstrate the prevalence of microplastics in both influent and effluent and highlight the potential for HPEI/PES nanofiltration membrane technology as a viable and scalable technology for the rejection of microplastics in wastewater.
This study examines how decentralising water resources management in South Africa has deepened inequity and inequality in water governance. Although integrated water resource management (IWRM) promotes participation, it fails to address power imbalances and historical inequalities rooted in Apartheid. This paper employs a systematic literature review and qualitative thematic analysis of 13 peer-reviewed studies, policy documents, and institutional reports published between 1998 and 2024. Using a thematic analysis approach, studies were coded according to themes of decentralisation, participation, and equity in South Africa's water governance framework. The findings reveal that IWRM's limited focus on social factors leads to superficial participation and worsening disparities. To address this, the study proposes 'developmental water management' (DWM), which combines participation, power, and equity within a developmental state framework for more inclusive water governance. The research calls for policy reforms, institutional changes, and active engagement with marginalised communities to ensure equitable water access for all.
The uThukela catchment area in South Africa plays a vital role in water provision, generating 25% of the country's water. The communities that live in these mountainous areas rely on the natural resources for their livelihoods. However, the absence of effective management plans and the lack of community involvement in conservation have had a negative impact on these natural resources. Degradation and the loss of grass cover on these steep mountain slopes have resulted in poor water infiltration, increased overland flow and severe soil erosion. Various initiatives in the area, starting with a pilot LandCare project, have built the capacity of the community to implement different erosion control techniques. However, there has been a lack of quantitative data on how successful the techniques have been. The aim of this project was to develop and implement a communitybased system to monitor the effect of rehabilitation efforts. The monitoring techniques successfully adapted for use by the communities were those utilizing splash boards, plant basal cover quadrats and runoff plots. All techniques were applied to eroded and rehabilitated sites. The most effective technique was the runoff plots where, for example, at the Oqolweni subward, runoff from the eroded site (2 680 mm) was 28% higher than from the rehabilitated site (1 950 mm) over an 8-month period. The monitoring results indicate that rehabilitation by the community has achieved a significant decrease in soil loss and runoff. However, no single technique can be recommended for rehabilitation as each technique has specific advantages and disadvantages. This monitoring project has played a key role in the government's Working for Water programme by establishing indicators for a form of 'payment for ecosystem services', whereby the government pays communal land users to manage and monitor environmental services, particularly the delivery of watershed services.
Groundwater chemical composition is dependent on various natural and anthropogenic factors. This study assessed factors influencing the groundwater chemical composition in an environment controlled by geological structures. The study further examined the suitability of groundwater quality for domestic and irrigation use. A hydrochemical approach was used to evaluate the main processes and activities influencing the groundwater chemistry. The main hydrochemical facies identified were mixed facies dominated by Na+ and HCO3- in the southwestern area, and MgCl / MgClSO4 / MgClHCO3, which dominated the northern area. Hydrogeochemical processes that were associated with the southwestern area groundwater were silicate weathering, ion exchange, carbonate and gypsum dissolution. The groundwater composition in the northern area, although controlled by carbonate dissolution, was influenced more by anthropogenic activities as indicated by the Cl/Br mass ratios of >88 and high Cl- concentrations. The high Cl- could not be attributed to halite dissolution due to its undersaturation in solution. Additionally, the northern area groundwater showed excess SO42-, which was linked to anthropogenic contamination. Groundwater in the southwestern area was suitable for domestic use, while that in the northern area was classified as unacceptable. The multi-tool approach used in this study provided a clear contrast between the northern and southwestern areas' groundwater, showing that these were influenced by distinct factors. This underscores the importance of developing area-based protection and management strategies that consider both natural processes and anthropogenic impacts.
The Pitman model is widely used in South Africa for hydrological modelling and water resource management. For the model to assist with ongoing water management, it needs to use the most recent observed rainfall data, which has proved challenging over the past decade due to data scarcity. This research aimed at that instead uses satellite-derived rainfall estimates for the simulation of stream flows. The framework was developed and tested in Catchments G, B, V, and L, as case study catchments representative of the diverse hydroclimatic regions of South Africa. CHIRPS estimates (1981-2019), downloaded at a quaternary catchment scale for the study catchments, demonstrated a generally strong monthly correlation (R2 > 0.7) with the WR2012 rainfall data. The satellite rainfall data (CHIRPS) were adjusted to correspond to the WR2012 rainfall data, and the Pitman model was set up and calibrated for the period 1981-2009, using the satellite rainfall data. Validation was done for the period 2010-2019. Calibration and validation were performed for 351 quaternary catchments in evaluating the suitability of using satellite data in modelling hydrological catchment responses. The simulated CHIRPS-based flows illustrated good similarity (triangle <= 4%) to observed flows. Further, a goodness-of-fit assessment of CHIRPS-based flows using 8 hydrological indices at a +/- 15% threshold of acceptable error was performed. The results demonstrated 78%, 73%, and 80% suitability of simulated CHIRPS-based flows for Catchments B, V and G, respectively. Catchment L had 'suspect' results, with indices illustrating inadequate correspondence between observed and CHIRPS-based flows. Based on satisfactory performance of the developed CHIRPS-based Pitman model framework, complementary application of CHIRPS rainfall estimates with the declining available observed rainfall data for the simulation of observed flows in data-scarce South African catchments is recommended.
This study addresses the critical challenge of sustainable wastewater treatment by investigating and valorizing agro-industrial residues as high-performance, zero-waste coagulants.The scope ofthis engineering investigation was the optimization and comparative assessment of 4 readily available materials-bentonite (BN), eucalyptus leaf powder (ELP), agave powder (AP), and the novel nopal fibrous residue powder (NFRP)-as alternatives to aluminium sulphate (AS) for urban wastewater treatment. The core novelty and innovation lie in the successful utilization of the discarded fibrous residue of the nopal cactus; this approach fundamentally shifts the paradigm from complex, resource-intensive extraction of nopal mucilage to the direct, simple use of a high-volume waste product. This leverages the lignin-and tannin-rich components, which are shown to be responsible for bio-flocculation, making the process intrinsically simpler, cheaper, and scalable, relative to state-of-the-art mucilage-based technologies. The statistical analysis confirmed significant differences in pollutant removal based on the material (p < 0.01). Agave powder (AP) was statistically superior for clarity, achieving a maximum turbidity removal percentage (TRP) of 97.76 +/- 2.180% at an optimal dose of 20 mg/L, statistically outperforming AS. Conversely, for the removal of organic pollutants, the chemical standard AS was superior in single-dose trials, with COD reduction (CODR) approximate to 88.5%. However, the synergistic combination of NFRP (100 mg/L) and BN (60 mg/L) achieved the highest CODR approximate to 92.13 +/- 0.398%, successfully exceeding the performance of AS. Furthermore, AP demonstrated high effectiveness in ammoniacal nitrogen removal (approximate to 75%), highlighting its multi-pollutant capacity.
Wetlands are vital to healthy ecosystems as they control floods and perform other important roles. Globally, the primary cause of wetland degradation is land use-land cover (LULC) change, a situation that also applies to Zambia. This research investigated LULC changes in the Bangweulu Wetland and its perceived drivers, using remote sensing, geographic information systems (GIS), questionnaires, and key informant interviews. The land was categorized into five types: settlements, grassland, cropland, water, and forest. The results showed a decline in forest (from 45 298.93 km2 to 33 233.52 km2), grassland (from 32 557.91 km2 to 26 418.19 km2), and water (from 2 410.72 km2 to 2 278.31 km2) between 1990 and 2020. In contrast, settlements grew from 356.69 km2 to 2 210.38 km2, and cropland expanded from 165.27 km2 to 5 108.13 km2. The perceived drivers of this change were also identified. Population growth was the most significant (3.76/5), followed by settlement expansion (3.66/5), declining ecosystem services (3.57/5), and forest loss (2.64/5). Minor perceived drivers included the built environment (2.21/5), recreation (1.54/5), and industry (1.34/5). Underlying causes involved agricultural development and energy needs, driven by market demands for charcoal and cash crops, which accelerate farming and deforestation. Understanding these local perspectives is essential for creating effective land management strategies and sustainable policies to conserve the Bangweulu Wetland's ecological functions.
This study focused on the fouling of two seawater reverse osmosis (SWRO) membranes at the Beni Saf Water Company desalination plant in Algeria, which has a daily capacity of 200 000 m3 and a recovery rate of 45% using 17 920 membranes. Approximately 3 234 membranes are replaced annually due to fouling. A detailed study of the fouling agents of the two membranes was conducted using various analytical techniques, such as moisture analysis, loss on ignition (LOI), determination of calcium carbonate (CaCO3) content, x-ray fluorescence (XRF), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). Surface characterization was also performed using scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (SEM-EDS), FTIR-ATR, and XRD. The LOI analysis indicated that more than 30% of the fouling material was organic in nature. FTIR-ATR identified the presence of -OH groups, phenolic C-O groups, and amide bonds, suggesting the accumulation of organic substances such as proteins, humic substances, and polysaccharides. Additionally, SEM-EDS, XRF, and XRD revealed relatively high concentrations of silica, primarily in the form of quartz, confirming the formation of an organo-inorganic complex on the membrane surface. Based on these findings, a sequential chemical cleaning protocol was developed, incorporating alkaline (NaOH), metal chelator (EDTA), surfactant (SDS), oxidant (H2O2), and sulfuric acid (H2SO4), each followed by rinsing with deionized water (DI). This cleaning regime effectively removed fouling from the membrane surface, resulting in an average weight loss of 15% for one membrane and 14% for the other.
This study explores integrating traditional Alajobi principles into the water-energy-food (WEF) nexus framework for sustainable resource management in Yoruba communities. The study utilised a qualitative approach that involved interviews and community observations in Akure, Ibadan, and Ogbomosho. Participants included community leaders, elders, local farmers, and community residents. The study revealed that Alajobi principles, such as non-maleficence, reconciliation, preservation, and collective responsibility, significantly influence resource management. These principles can enhance the sustainability and resilience of WEF resources. This research analyses the potential of traditional practices in addressing modern sustainability challenges, contributing a unique perspective to WEF nexus research. Integrating Alajobi principles can foster community cohesion, respect for nature, and sustainable practices. The study recommends incorporating traditional practices into modern resource managementframeworks and raising awareness about Alajobi principles to enhance the sustainability of WEF resources.
Water quality in South Africa's river systems is declining, driven in part by changes in land use and management. Diffuse pollution significantly contributes to river degradation, requiring identification of critical source areas of diffuse pollutants, including nutrients and suspended solids. This study assesses diffuse pollution risks in two contrasting catchments: the Thukela and the Breede. A risk-based assessment was undertaken using the Sensitive Catchment Integrated Modelling Analysis Platform (SCIMAP). SCIMAP integrates a digital elevation model (to determine hydrological connectivity), land use based diffuse pollution potential, here assessed from national land cover classes using the Automated Land-based Activity Risk Assessment Method (ALARM), and rainfall information (representing runoff dilution potential). Results are presented as (i) risk generation of diffuse nutrients based on land use attributes, (ii) the connectivity risk of the movement of pollutants to the river channel, (iii) nutrient risk from the landscape component's critical source areas, (iv) nutrient concentration risk in the channel component of the catchment, and (v) suspended solid risks from the landscape component. In the Thukela Catchment, landscape-scale nutrient risk patterns were relatively uniform at catchment scale, with distinctions only emerging at finer spatial scales, where elevated risks were associated with some commercial and subsistence agricultural areas. The Breede Catchment exhibited distinct nutrient risk patterns even at catchment scale, with high-risk areas closely linked to some commercial agriculture areas. Channel segments of high nutrient risk for both catchments became evident only at detailed spatial scales. Landscape-based diffuse suspended solids risk areas within the Thukela Catchment range from lows under undisturbed natural vegetation or areas of low connectivity, to highs dominated by degradation and subsistence farming, combined with a high connectivity risk. The Breede Catchment was more muted. This approach is useful to backtrackfrom polluted river sections to areas with high risk of generating and mobilising pollutants.
The application of sewage sludge to agriculture is particularly risky in sandy soils, due to pollutant mobility. However, these nutrients are most needed in these soils, which are widely distributed in Southern Africa. This perspective piece investigates the co-amendment of water treatment residuals (WTR) to promote soil integrity, analogous to the sorptive properties of clay, fortifying nutrient-poor sandy soils to receive sewage sludge. Ecological motivations like biomimicry, environmental carrying capacityand evolutionaryadaptation were explored. Land application was compared to other sludge re-use options, focusing on practical considerations.The local distribution ofsandysoils and theiragricultural consequences were mapped, with an exploration of the high-value crops ideal for this strategy-harnessing crop growth for pollutant remediation and minimizing downstream market risks. The economic benefits and challenges were explored in the 'sandbox' of the Philippi Horticultural Area, where a co-diversion strategy was modelled using simple cost analyses. Public participation was explored through the vehicle of eco-conscious markets and certification. Finally, a relatively consistent WTR and sewage sludge production ratio was shown across provincial, national and international urban development, a golden thread facilitating this waste management strategy.
In 2018, the City of Cape Town (CCT) in South Africa came close to 'Day Zero' - the day taps would run dry due to an extreme drought that began in 2015. With severe droughts likely to be common in future, this study investigated the potential for catchment-scale stormwater harvesting facilitated by the transformation of stormwater ponds into reservoirs. In this new approach, water levels in the ponds would be dynamically managed using real-time control (RTC) to ensure continued use as flood control infrastructure. The study was restricted to the 89 km2 Zeekoe Catchment situated on the Cape Flats in the southern part of the city. Assuming the water would be used for outdoor non-potable uses such as agriculture and residential gardens, the temporal mismatch between the seasonal demand and winter rainfall meant limited supply. Stormwater could meet a limited percentage of the demand, but with most lost to the sea as overflow. To minimise the effect of the mismatch, it was determined that at least 4 Mm3 balancing storage i.e., 20-30% of the mean annual stormwater volume estimated at 18 Mm3, was required. The available 1 Mm3 storage (5.5% of the mean annual stormwater volume) in the catchment was found to be inadequate as the stormwater supplied from the storage would only meet 44-60% of the demand, with a spill (water lost as overflow) of 35-51%. Dynamic management of the ponds with RTC was investigated to provide the required storage. This involved continuous adjustment of stormwater flow rates with a set of rules to optimise storage capacity. With this management approach, it was possible to achieve the required 4 Mm3 to meet the identified demand in the study area and minimise the loss through spill.
The City of Cape Town in South Africa faced the possibility of taps running dry in 2018 due to a prolonged drought that commenced in 2015. With such droughts expected to reoccur frequently in future, this study investigated the prospects for managed aquifer recharge (MAR) with stormwater.This would require temporary storage to collect and hold the stormwater during and immediately after rainfall events while it seeps into the aquifer. The 89 km2 Zeekoe Catchment located in the southern part of Cape Town was selected as a case study as it had both existing surface storage (61 stormwater ponds) and was lying above a large unconfined aquifer. As the stormwater ponds were largely designed for flood control, they would need to be modified for MAR. In this desktop study, the main objective was to model temporary detention of stormwater in the ponds with the aim of predicting infiltration into, and thus augmentation of, the aquifer. The requirement that the flood control function be maintained, combined with the limited capacity in the ponds, was a keyconsideration. The study determined that the physical characteristics in the Zeekoe Catchment, i.e., largely flat terrain, pervious sandy soils, and a relatively deep (20-50 m) unconfined aquifer, could support managed aquifer recharge and borehole abstraction rates of 3.5-8.1 L/s per borehole from some 140 boreholes. This could provide a mean annual groundwater yield of 29-33 Mm3 (about 15% of Cape Town water demand in 2018).
Water reticulation systems (i.e., premise plumbing) serve as a reservoir for opportunistic premise plumbing pathogens (OPPPs) to survive within these premise systems. OPPPs can be transmitted to individuals mainly via inhalation of aerosols from these water systems. These OPPPs can adapt, thrive and survive under a range of different conditions, which include high temperatures and low oxygen levels during stagnation, conditions often associated with household plumbing systems, including hot water systems (HWS). Hospitals are of specific concern as infections caused by OPPPs predominantly affect individuals who have underlying illnesses or health conditions. The current South African National Standard (SANS) 241 for drinking water does not provide information regarding testing for the presence of OPPPs, while the SANS 893 and 893-1 standards only provide a guideline for Legionella in water systems. The presence of OPPPs within HWS and premise plumbing is a concern, and a need exists to establish remediation and mitigation measures to control the presence of OPPPs in buildings. This review addresses risk analysis, evaluation and measures, which include the control of geyser temperatures and training of plumbers, as well as sampling and detection of OPPPs. This should limit the number of infections amongst individuals and will thus lessen the financial burden on health care systems and the economy.
Urbanization has placed pressure on urban stormwater infrastructure. Previously implemented stormwater master planning had become inadequate in managing floods. Research has shown that the use of sustainable drainage systems (SuDS) assists in mitigating the effects of the change in impervious areas brought about by urbanisation. While research on the usage and functions of SuDS is widely available, there is a lack of literature on the impact of indigenous ground cover categories in reducing stormwater runoff within bioswales in South Africa. The aim of this study was to evaluate the impact of indigenous ground cover categories on the hydrological performance of a bioswale in reducing stormwater runoff volume and peak. A physical simulation model was constructed to assess the water balance of the bioswale, taking into account the soil water content of the engineered soil medium. The effects of the inflows in the simulation model were addressed by mimicking the 1-in-10-year post-development return period stormwater runoff scenario, within the Gauteng Province, South Africa, during the summer rainfall pattern. The lawn category (kweek /Cynodon grass) demonstrated an average volume reduction of 54.7%, with a peak flow reduction of 49.9%. Ornamental grasses and veld grasses also exhibited a volume reduction (42.2% and 38.0%, respectively) and peak flow reduction (40.4% and 38.3%, respectively). Additionally, these grass categories influenced the soil water content. Overall, these findings demonstrate that there is potential for various grass types to mitigate stormwater runoff.
