Conference Publications

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The 2020 WMO symposium on climatological, meteorological and environmental factors in the COVID-19 pandemic: A special issue from symposium presentations
(2021-06) Sweijd, Neville; Zaitchik, BF
The COVID-19 pandemic has become one of the great historical events of the modern era, presenting a generational challenge to the world. Questions about the role of weather on SARS-CoV-2 transmission led to the gathering of scientists at an online event, the “International Virtual Symposium on Climatological, Meteorological and Environmental factors in the COVID-19 pandemic,” convened on 4–6 August 2020 under the auspices of the World Meteorological Organization. This collection of papers arise from the Symposium.
84th IMESA Conference in collaboration with IAWEES (International), Virtual conference, Cape Town, 17 - 19 November 2021
(2021-11) Steyn, Maronel; Walters, Chavon R
Water scarcity, increased pollution, unprecedented population growth and climate change are collectively driving the need to reuse water with the aim to enhance water security, sustainability, and resilience. It is clear that South Africa¿s already strained water resources will become even more stressed in the near future. The Department of Water and Sanitation predicted that by 2030 water demand will reach 17.7 billion m3, far more than what is available to allocate. An Atlas for potential industrial bulk scale water reuse was produced from publicly available Natsurv and WARMS data. A web-based Decision Support System (DSS) tool is being developed to enable municipal and industry partners, and water quality managers to make informed decisions for possible reuse options. The tool aims to directly assist by linking industrial effluent volumes and quality to fitness for use, and linking it with specific industries in the geographical vicinity based on industry specific water quality and quantity requirements.
Advancing ecosystem accounting in estuaries: Swartkops Estuary case study
(2023-03) Taljaard, Susan; Van Niekerk, Lara; Adams, JB; Riddin, T
Rapid degradation of ecosystems and loss of ecosystem services have sparked interest in developing approaches to report and integrate such change with socio-economic information systems, such as the System of National Accounts. Here we describe an approach and application of ecosystem accounting for individual estuaries, building on approaches previously applied at national and bay levels. Using the Swartkops Estuary as a case study, the focus is on physical accounts for ecosystem extent and condition, as well as accounts for two important ecosystem services (carbon sequestration and recreational use). Pressure accounts are also introduced to demonstrate the value of identifying key areas for management and restoration interventions in response to changes in extent and/or condition accounts. Greater resolution in these account reports, achieved through zoning, provides spatially explicit information on ecosystem assets and their services within an estuary to also inform management decision-making at local level. Further, these accounts can also inform local restoration prioritisation, in support of the UN Decade on Ecosystem Restoration (2021–2030), for example offsetting irreversibly degraded areas in one zone with restoration or maintenance of similar habitats in another.
Advocating circular economy in wastewater treatment: Struvite formation and drinking water reclamation from real municipal effluents
(2020-08) Mavhungu, A; Masindi, Vhahangwele; Foteinis, S; Mbaya, R; Tekere, M; Kortidis, I; Chatzisymeon, E
In this pilot study, the circular economy concept in wastewater treatment was examined, through a zero liquid discharge (ZLD) process where struvite was recovered and drinking water was reclaimed. A stage wise approach was followed for struvite formation and the subsequent reclamation of drinking water. Specifically, the early stages of treatment entail the synthesis of struvite via the chemical precipitation of nutrients (phosphate and ammonia), using thermally activated cryptocrystalline magnesite. Thence, reverse osmosis (RO) was employed for drinking water reclamation. With this dual approach, 3.5m3 of municipal wastewater were successfully treated at a pilot plant in South Africa, producing ~52.5 kg of struvite and ~3.4 m3 of drinking water. The operating parameters were 30 min of residence time, 0.5 g : 500 mL solid to liquid (S/L) ratio, using ambient temperature and pH. X-ray diffraction (XRD) and High Resolution Scanning Electron Microscopy (HR-SEM) coupled with electron dispersion spectroscopy (EDS) confirmed the synthesis of struvite and the presence of notable Mg/P ratios. Fourier Transform Infrared Spectrometer (FTIR) further ascertained the obtained results. Moreover, it was identified that the reclaimed water meets the South African National Standard (SANS) 241:2015 and the world health organisation (WHO) standards for drinking water. An economic analysis revealed the viability of the process, suggesting that the system could be self-sustainable. Therefore, the results of his work indicate that introducing the concept of circular economy in wastewater treatment can promote the sustainable management of the ever-increasing quantities of municipal wastewater and at the same time address problems of emerging concern, such as water scarcity and phosphate shortage.
Appropriate renewable energy for education infrastructure in rural South Africa: The Cofimvaba science centre model
(2020-11) Nice, Jako A
The Council for Scientific and Industrial Research (CSIR) has embarked on an innovation investigation through a ministerial initiative brought by the Department of Science and Technology Innovation (DSI). The Cofimvaba Science Centre was envisioned, planned and is currently in construction to build and test theory with regard to the efficacy of multiple innovations in the supply and delivery of building construction projects in South Africa. This is in response to the target set by the National Development Plan (NDP 2011:288) of 2030 for energy efficiency in building standard SANS 204 to achieve ‘zero carbon’ buildings. There is a need for alternative teaching platforms for maths, science and technology. At the same time, there is a need for rapid construction of infrastructure with sustainable ongoing power supply in rural areas in South Africa. The innovations could lead to improved teaching outcomes and quality of instruction, as well as improvement in the rate of construction and service delivery, with the added benefit of future economy creation downstream. The building has been constructed by alternative construction methods and materials, with five different energy sources regulated through a microgrid system delivering a planned net zero carbon building. A multiyear building performance analysis will be conducted to gather evidence for future application and appropriateness. A pre-construction investigation of available building technologies was done, and during construction assessments of renewable energy sources and the financial viability of the project continued. Post-construction assessment of the building’s performance will be conducted covering materiality, thermal performance, indoor air and sound quality, energy, water and waste use. The alternative building construction method has yielded rapid construction time. However, a slow administrative process has delayed the completion date. Nevertheless, the project suggests that net zero energy can be achieved for Government and private buildings in rural South Africa.
Assessing alternative supporting organic materials for the enhancement of water reuse in subsurface constructed wetlands receiving acid mine drainage
(2022-06) Oberholzer, MM; Oberholster, PJ; Ndlela, Luyanda L; Botha-Oberholtster, AM; Truter, CJ
Acid mine drainage (AMD) is a global problem with severe consequences for the environment. South Africa’s abandoned mines are a legacy from the country’s economic dependence on the mining sector, with consequent negative impacts on ecosystems. AMD remediation includes active and passive techniques. Constructed wetlands (a passive technique) have lower operational costs but require larger spaces and longer timeframes to achieve the remediation of AMD, and are supported by anaerobic sulphate-reducing bacteria (SRB), which capable of remediating high-sulphate-laden AMD while precipitating dissolved metals from the AMD. Organic substrates supporting these activities are often the limiting factor. When enhancing existing passive AMD remediation technologies, alternative waste material research that may support SRB activity is required to support the circular economy through the reduction in waste products. Chicken feathers show potential as a substrate enhancer, boosting organic carbon availability to SRB, which sustains passive AMD treatment processes by achieving pH elevation, sulphate and metal reductions in AMD water for reuse. Microbial biodiversity is essential to ensure the longevity of passive treatment systems, and chicken feathers are proven to have an association with SRB microbial taxa. However, the longer-term associations between the AMD water parameters, microbial diversity and the selected substrates remain to be further investigated.
Assessment of food losses and waste at the Tshwane market and small scale farms
(2021-02) Ramukhwatho, Fhumulani R; Oelofse, Suzanna HH; Musvoto, Constansia D; Polasi, Letlotlo T
Food losses and waste are issues of global concern as they contribute to greenhouse gas emissions. It is estimated that agricultural production and marketing contribute a large portion of food waste in the value chain. This paper reports on findings of a research study conducted in Tshwane Fresh Produce Market (TFPM) within the City of Tshwane Metropolitan Municipality (CTMM) and on small-scale vegetable farms in Limpopo province. The aim of the study was to assess food losses and waste in a small-scale production context and at a fresh produce market. Questionnaires were used to collect information on the amount of food wasted or lost, reasons for the wastage and methods employed to reduce waste. It was found that food loss varied depending on the crop, and even on the variety of produce. The main causes for food wastage at the farm level are weather conditions, damage from insects and birds. Sixty percent of farmers divert their food waste for animal feeding. On average five thousand tonnes of food is wasted every year in the Tshwane fresh produce market and the main cause of wastage is oversupply by farmers. The study concluded that the highest losses occur at the preharvesting stage and growers often have little control over how much produce is lost.
ASTRAL pool of technologies: A technology validation perspective within the Atlantic Area
(2024) Pias, M; Guterres, B; Orazi, G; Paris, M; Drews, P; Oliveira, V; Botelho, S; Duarte, N; Poersch, L; Smith, Marie E
This presentation focused on various issues within the aquaculture sector, as well as Integrated Multi-Trophic Aquaculture (IMTA) and ASTRAL Pool of Technology Innovations.
ASTRAL pool of technologies: Digital twins to support IMTA within the Atlantic area
(2022-09) Pias, M; Orazi, G; Drews, P; Paris, M; Dupont, C; Smith, Marie E; Michalek, K; Lain, L; Martinez, J; Khelifi, I
Presentation on the ASTRAL pool of technologies: Digital twins to support IMTA within the Atlantic area.
Battery energy storage systems value chain analysis for the identification of opportunities for enterprise development
(2023-10) Pandarum, Aradhna; Rakaibe, Tshwanelo K; Mbam, Vuyo
South Africa is confronted by the triple threat of inequality, poverty, and unemployment and has the highest inequality and unemployment rate in the world. The energy transition to a low carbon economy offers significant opportunity for the country to stimulate economic growth and overcome some of the social challenges faced by pursuing investments to reindustrialise the economy. The country is expected to experience a significant investment in renewable energy as part of the energy transition. However, increased penetration of renewable energy demands other technologies to ensure that grid stability is maintained. Battery energy storage is seen as one such technology and according to the Integrated Resource Plan of 2019 and Eskom’s latest Transmission Development Plan it is expected that a capacity between 2GW and 6.6GW will be required to be installed by 2032. This indicates the potential investment that will need to be made for battery storage thus highlighting the potential opportunity for localisation and industrialisation of such value chains. Thus, this paper seeks to detail the activities, products and services required for lithium-ion and vanadium flow battery energy storage systems value chains with the inherent aim at unpacking potential enterprise development opportunities that exist. The paper will detail the upstream, midstream, and downstream activities within the value chains, key market competitors, barriers and possible solutions for reindustrialisation in the country.
Breakthrough studies for the sorption of methylene blue dye from wastewater samples using activated carbon derived from waste banana peels
(2023-05) Ramutshatsha-Makhwedzha, D; Munyengabe, A; Mavhungu, ML; Mbaya, R; Baloyi, Siwela J
In the current study, an activated carbon derived from waste banana peel using H2SO4 was applied for the first time in a packed-bed column for methylene blue (MB) dye removal from wastewater. The pore structure and surface of banana peel activated carbon (BPAC) were investigated using X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and Brunauer-Emmett-Teller analysis to discover the mechanism of MB sorption. The produced BPAC by H2SO4 activation agent has surface area of 361.86 m2/g and exhibits good thermal stability. The extent of MB breakthrough performance was examined by optimizing flow rate, bed mass, and initial concentration at pH 9. The column’s dynamics revealed a strong dependence of breakthrough curves as a function of process conditions. The breakthrough time (tb), volume of liters processed (L), and adsorption exhaustion rate all increased as bed mass increased but decreased as flow rate and initial concentration increased. Applying linear regression to the experimental data, Yoon-Nelson and Thomas’ kinetic model was used to extract column characteristic parameters that could be used in process design. Using environmental water, the waste banana peel activated carbon material demonstrated effectiveness in removing MB to below acceptable levels by processing 1.16 L of water with an initial MB concentration of 40 mg/L using 8 g of sorbent. Nitric acid (3M) was able to regenerate the exhausted bed. Moreover, the sorbent was reused four times with no significant capacity loss. It can be concluded that waste banana peel activated carbon medium is an alternative solution to remediate MB-contaminated wastewater.
Bulk scale industrial effluent reuse potential in South Africa Atlas
(2021-10) Steyn, Maronel; Walters, Chavon R; Mathye, Salamina M; Thwala, Melusi; Ndlela, Luyanda L; Tancu, Yolanda; Lehutso, Raisibe F; Banoo, Ismail
Globally, responsible and efficient water management is fast becoming a pressing reality for domestic users, agriculture and industry alike. The challenge is therefore to capitalise on the limited water we currently have. Solution: Bulk-scale reuse of industrial water effluent can play a significant role in water security in a water scarce country, such as South Africa, as it can augment or partially substitute freshwater resources needed for domestic purposes and future development. Water reuse in South Africa is however lagging. Approach: An Atlas for potential industrial bulk scale water reuse was produced from publicly available Natsurv and WARMS data. It highlights the urgent need for water reuse to form an integral part of an integrated water management supply approach in South Africa.
“A can of worms”: Aerosol waste within the context of EPR, some insight from South Africa
(2022-10) Muswema, Aubrey P; Oelofse, Suzanna HH
According to Extended Producer Responsibility (EPR) regulations, the paper and packaging sector needs to prepare EPR schemes for management of their end-of-life products. The aerosol sector recognises that aerosols present somewhat different challenges at end-of-life when compared to other types of packaging waste due to the nature of aerosols in comparison to paper and packaging. The Aerosols Manufacturing Association (AMA) therefore initiated background research to determine the feasibility of developing an aerosol specific EPR scheme. The CSIR was commissioned to conduct research to determine the current practices relating to end-of-life management and the associated challenges posed by aerosol cans as part of the packaging waste stream. This paper presents the findings from a survey focussing on aerosol waste management practices and the challenges hampering increased recycling rates. EPR is a good option for implementing recovery of aerosol wastes. It should be considered that aerosol waste can be divided into pre- and post-consumer waste. There are instances where individual manufacturers have implemented recovery of pre-consumer aerosols, but respondents indicated that there are currently no formal takeback programs at municipal level for spent post-consumer aerosols. The informal sector does recover some of these items from households (post-consumer), but in general it was reported that buy back centres are reluctant to accept poorly dismantled aerosol cans. A challenge for collection is the low post-consumer volumes of aerosol can waste from households. Poorly managed aerosols do have several negative environmental, health and safety impacts. There is a need for more training and education on the specific requirements for handling and disposing of aerosol waste for the different stakeholders involved. There is also a need for innovative recycling technology which is simple to implement, and which is cost effective. Efforts should ideally be focussed on the pre-consumer waste streams, which can be recovered in relatively large volumes. The post-consumer waste streams present a co-mingled challenge, hence a ‘can of worms’ to mitigate. The findings of this research also provided evidence to AMA to inform their approach to EPR.
Case studies of modified South African estuaries and implications for ecological restoration in these systems
(2019-09) Weerts, Steven P; MacKay, F; Taljaard, Susan; Van Niekerk, Lara
Presentation on the case studies of modified South African estuaries and implications for ecological restoration in these systems.
Challenges in water reuse: Pharmaceutical removal efficiency in Durban’s Wastewater Treatment Plants
(2024) Kaium, A; Nocanda, Xolani W; Robinson, R; Fick, J
The study highlights the variability in pharmaceutical removal efficiencies among different WWTPs in Durban. Advanced treatment processes, such as those used at the MEB and DWR, showed the best removal rates. However, traditional WWTPs like Northern and Umbilo require further optimization to remove pharmaceuticals effectively.
Circular economy and human settlements
(2022-09) Cooper, Antony K
This invited presentation provides an overview of the circular economy in human settlements in South Africa, with some examples.
Classroom acoustics: A case study of the cost-benefit of retrofitted interventions
(2023-12) Van Reenen, Coralie A
It is known that classroom acoustics is important for effective learning. To this end, many countries have developed classroom acoustics standards. However, research shows that these standards are often not implemented. Research evaluating the implementation of classroom acoustic standards internationally concludes that successful implementation is driven by mandatory standards that are part of building codes and that the cost of compliance is a barrier. The study presented here explores the cost of upgrading classrooms to achieve a suitable reverberation time. The paper presents a case study in South Africa, where acoustic standards are generally not implemented and cost and know-how are barriers. The objective was to optimise the cost, acoustic benefit, and accessibility of acoustic interventions. Four different acoustic interventions were temporarily installed in a classroom, simulating floating sound-absorbing ceiling panels constituting 25% of the ceiling area. The weighted sum model was used to assess the suitability of each intervention, taking into account the cost, acoustic benefit (in terms of reverberation time) and ease of access to purchase the materials. The case study demonstrates that a noticeable improvement in acoustic conditions can be achieved without significant cost and provides a basis for further research to develop simple standardised design recommendations.
Climate change and the Knysna Estuary
(Knysna Basin Project, 2023) James, J; Van Niekerk, Lara; Lamberth, S; Whitfield, A; Breen, C; Read, R
Estuaries are shallow coastal environments that are influenced by both tidal action and freshwater inflow. As a result of the mixing of marine and fresh waters, estuaries are naturally dynamic, unstable environments with physico-chemical conditions oscillating on hourly, daily, seasonal, yearly and decadal scales1. Climate change is expected to modify the physical structure and biological functioning of estuaries, by changing the magnitude of these oscillations, as well as changing long-term average physico-chemical conditions (such as average temperature, salinity and dissolved oxygen levels). In addition to rising temperatures, climate change in the coastal and estuarine environment also incorporates changes in temperature variability (land and sea), winds and ocean currents, freshwater flow (rainfall), extreme weather events, sea level and ocean acidification; all of which will have profound consequences for species living in estuaries. In this chapter these different drivers of change, such as temperature, rainfall and hydrology, floods and droughts, sea level rise, storm surges and ocean acidification are reviewed with a focus on the effects of these drivers of change on the Knysna Estuary.
Coastal vulnerability and climate change adaptation in South Africa: Remote sensing challenges and opportunities
(2022-05) Lück-Vogel, Melanie
South Africa is nestled between the Atlantic, the Southern and the Indian Ocean. Its coast is about 3000 km long and comprises 300 estuaries. Its coast stretches across three bioclimatic regions, namely the Cool Temperate South-West, a Warm Temperate South, and a Subtropical East. Accordingly, natural coastal vegetation includes desert-like sparse low shrubs on the west coast, dense evergreen fynbos shrublands in the south and subtropical thickets and coastal forests in the east. Being a very attractive environment for economic and leisure activities, the population in the coastal zone and the related land use pressure are extremely high: In South Africa, about 40% of the population lives within 60 km of the ocean and in 2011 an estimated 3.5 million South Africans resided within 5-7 km of a coastline, and 60% of these people were in the four densely populated metropolitan areas. Populations in coastal municipalities grew by approximately 1.8 million people between 2001 and 2011, and this rate, which far exceeds national growth rates in other areas, continues to date. This continued growth increasing forces urban sprawl into spaces affected by coastal dynamics and predicted climate impacts such as increased storm frequency and intensity and sea level rise. Both, human development pressure and predicted climate change impact alert to the need of effective integrated spatial planning and geospatial vulnerability assessments, as well as preservation of natural coastal environments and the services these ecosystems provide. South Africa has embraced this challenge and is conducting various projects that will provide information to guide decision making in these challenging and complex fields.
Compound flooding due to interaction of waves and river discharge at Breede Estuary, South Africa
(2022-05) Kupfer, S; Santamaria-Aguilar, S; Pieterse, Amy; Lück-Vogel, Melanie; Vafeidis, AT
Recent studies on compound flooding have considered the interaction of storm-tide and fluvial or pluvial flood drivers, whereas the contribution of waves to compound flooding so far has been neglected. In this study, we investigate compound flooding from waves, tides and river discharge at Breede Estuary, South Africa, using a hydrodynamic model. We estimate the contribution of extreme waves to compound flooding by analysing the driver interaction and by quantifying vertical and horizontal differences of flood characteristics. We further consider the additional effect of waves on flood timing and compare results of compound flood scenarios to scenarios in which single drivers are omitted. We find that flood characteristics are more sensitive to river discharge than to waves, particularly when the latter only coincide with high spring tides. When interacting with river discharge however, the contribution of waves is high, causing larger flood extents and higher water depths. With high wave intensities the first flooding can begin up to 12 hours earlier. Our findings provide insights on the magnitude and timing of compound flooding in an open South African estuary and demonstrate the need to account for the effects of waves during compound flooding in future flood impact assessments of similar coastal settings.

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