South Africa’s options for mineimpacted water re-use: A review

Abstract

South Africa is a water-scarce country and is currently rated as one of the 30 driest countries in the world, with an average rainfall of 490 mm/a, approximately half of the global average. As an indicator of the degree of regional variability in South Africa's water supply, it has been shown that 70% of all runoff is from approximately 20% of the land area. Regardless of the water scarcity faced in South Africa, our water conservation track record is poor, with an average consumption of 280 L/d per person, almost 60% more than the global average of 175 L/d per person. Around 40% of this allocation is utilized in watering lawns and gardens (Zhuwakinyu, 2017). The South African government predicts water demand to outstrip supply as early as 2025. On an international scale, the situation appears just as dire, with the United Nations High Level Panel on Water (HLPW) expecting a 40% water shortfall by 2030, which may affect up to 1.8 billion people based on current water demand trajectories (Zhuwakinyu, 2017). Currently, South Africa is experiencing the worst drought since 1904, which has triggered severe water shortages, negatively affecting agricultural output in all sectors (News24, 2016). The potential exists for nationwide 'water-shedding' initiatives, similar to the electrical load-shedding programme initiated by Eskom, being implemented for homes and businesses in the near future if the situation continues to decline. Currently, water restrictions are in place country-wide with the Western Cape being the worst affected province. In 2016, eight of the nine provinces, with the exception of Gauteng, were declared drought disaster areas. The country's total water supply is currently estimated at 14.6 km 3 /a, of which surface water is the main source. The current demand is estimated to be between 15 km 3 /a and 16 km 3 /a, and it is expected that South Africa will experience a 17% water supply and demand gap by 2030 (Webb, 2015; News24, 2016; Zhuwakinyu, 2017). The UN World Water Development Report (2017) argues that improved wastewater management could facilitate the achievement of the UN's 2030 Sustainable Development Goals (SDGs). SDG-6 specifically has a target to reduce the proportion of untreated wastewater by half by 2030. while sustainably increasing water recycling and safe re-use (WWAP, 2017). The report also suggests that wastewater which is traditionally discarded could be treated to provide a non-potable water resource for use in agriculture and energy production. According to the Water 2017 Report, more than 50 countries

Potato (Solanum tuberosum L.) cultivars physiological, biochemical performance and yield parameters response to acid mine water irrigation and soil physiochemical properties

“…Irrigation with AMD water generally causes a shift in the parameters of soils, has the potential to positively alter microbial diversity and plays vital roles in the ecology of the rhizosphere of plants through the maintenance of soil health and therefore increasing the yield of crops 75 – 77 . The decrease in the yield of crops irrigated with treated AMD water could be a function of the important microbe reduction during the process of treatment 6 . Hence, there is a need to evaluate a system where AMD treatment can protect the important microbial communities while removing the harmful substance that plants can translocate from the soil.…”

Active Physical Remediation of Acid Mine Drainage: Technologies Review and Perspectives

“…Pre-filtration of the concentrated brine stream, on the other hand, remains crucial, and the concentrated brine stream can be treated in nitrifyingdenitrifying bioreactors (Häyrynen et al, 2009). Application of this technology is the development of an AMD treatment facility near the town of Emalahleni, South Africa, to address the enormous volume of AMD generated by coal mining activities in the region (Grewar, 2019;Santos et al, 2021). The AMD treated at this facility is mostly derived from active and abandoned coal mining activities and is characterized by a high sulfate level and a relatively low metal content.…”

Mine drainage: Remediation technology and resource recovery

“…A review was completed on the reuse of treated mine water in South Africa to replace high‐quality water (Grewar, 2019). It was concluded that reuse of treated mine water in crop irrigation was the most suitable option.…”