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.
