Managed aquifer recharge in South Africa (MARSA)

project summary

Existing freshwater resources are threatened by overexploitation due to population growth, urbanisation, and climate change and many regions experience water shortage. South Africa is a water-scarce country and during the 2017-19 Southern African drought, water suppliers experienced severe difficulties supplying enough water to the population. Water scarcity is expected to become even more critical in the future due to climate change and improved utilization of available water resource is therefore urgent. Managed aquifer recharge (MAR), the purposeful recharge of water to aquifers for subsequent recovery, is used globally to replenish over-exploited groundwater resources. Due to increased water shortage worldwide, there is growing interest to use unconventional water resources for MAR such as reclaimed water. This, however, raises major concerns related to pollution of the drinking water resources. The primary aim of MARSA is to develop MAR technologies that allow for a broader span of water qualities to be used for MAR. It is hypothesised that improved removal of organic pollutants, nitrogen species, and pathogens from e.g. reclaimed water can be achieved by establishment of reactive barriers or injection of oxidizing agents to anaerobic aquifers during recharge as different redox environments are thus created. First, we will investigate the capacity of South African aquifer sediments to remove organic pollutants, nitrogen species, pathogens, and antimicrobial resistance genes and how this can be improved. Then specific MAR technologies will be tested at field conditions in South Africa using real Berg River water or reclaimed water. Finally, the potential of implementation of MAR for the groundwater resource in South Africa will be assessed considering the use of broader spans of water qualities for recharge. The outcome of MARSA will be new MAR water recycling tools to be used by water managers to combat water scarcity in South Africa and globally.