During the lockdown of 2020, we began developing a residential plot in the Overberg region of the Western Cape.
Water rushed out of the borehole on the site like there was no tomorrow – but it turned out to be as brak as can come. It’s not for nothing that the river running along the edge of the village is called Soutrivier.
Discovering this, we set aside plans to build and turned to what seemed to be a more urgent priority – exploring if all this water under out feet can be turned into a useful resource, to benefit one and all.
So was born the idea for the Klipdale Groundwater Phytoremediation Project . . .
Klipdale Groundwater Phytoremediation Project
A pilot study
We entered for the UNDP-WRC Water Innovation Challenge and won a small grant that would enable us to set up a basic infrastructure to run small-scale tests to ascertain the performance of known phytoremediation plant species in the cleaning of groundwater.
In order to meet the grant conditions, we needed to do a lot of preparatory work and get going in a very short time. The community of Klipdale pitched in, among others things to erect a greenhouse, which is essential for testing to ensure the integrity of the groundwater during the rainy season.
Our pilot study involves small-scale tests with various species to see if they can make brackish water suitable for irrigation and even domestic use.
Among the plant species we have on trial are chrysopogon zizanioides, commonly known as vetiver; typha capensis (bulrush); lemma minor (duckweed); pontederia crassipes (water hyacinth), salicornia decumbens – a succulent halophyte, and the mangrove species avicennia marina.
This is the first experimentation of its kind, the objective being to create an innovative low energy technology to treat existing groundwater supplies at household and local scales.
The system is envisaged as a network of planted ponds of various sizes that are fed continuously by one or more boreholes.
The Power of Plants
Digging into our water problem, we learnt that only one percent of the water on Earth’s surface is usable by humans and 99% of the usable quantity is underground. But brackish, or saline, groundwater is a major problem. According to one study, about 1.1 billion people live in areas with groundwater salinity at shallow and intermediate depths.
Irrigation, seawater intrusion, weathering and rock activity are some of the causes of groundwater salinity. It can cause health problems, decrease agricultural yields and profits, destroy fertile agricultural lands, jeopardise livelihoods, increase costs of infrastructure maintenance, costs of industrial processes and change or destroy eco-systems. All this of course is very much dependent on how the groundwater is used to meet the water demand for these processes and activities and dependent on the level of salinity of the groundwater applied.
Worldwide, phytoremediation is a well-proven technology in the treatment of waste water, and the ability of plants to absorb or break down polluting elements are well-documented. In South Africa, phytoremediation technology is effectively used to treat waste water from mines and other polluting industries. In essence, the Klipdale Groundwater Phytoremediation Project is not proposing the development of a new technology, but the innovative use of phytoremediation to make groundwater accessible in South Africa’s rural communities.
Despite the significant potential of phytoremediation as a technology to increase access to clean water, it has not been researched and developed as a solution to treat poor quality groundwater. The plants that could clean brackish groundwater have not been identified, though they certainly exist. The potential for modelling and scaling up such an innovative phytoremediation project has yet to be established.
Why does this matter? Reverse osmosis (RO) technology is the typical solution used to clean brackish groundwater. While it does the job, it is an expensive technology that is not deployed to improve the access of poor, rural South Africans to clean water. RO technology demands ongoing investments in energy to drive the solution. RO technology produces toxic waste.
There is a significant opportunity for a more cost-effective, environmentally-friendly technology that would enable poor, rural communities to access clean water from their own land.
COVID-19 has highlighted the severe impacts of the lack of access to clean water in South Africa’s rural areas. There have been schools unable to re-open because lack of clean water and sanitation systems mean they cannot meet the basic COVID-19 prevention requirement – to wash hands. The pandemic has also set in motion economic hardships that have worsened food security and leave huge numbers of people vulnerable to under-nutrition and social unrest.
Access to potable water is vital for food production too. Community food gardens, school food gardens and home food gardens are unsustainable in water-scarce South Africa without the deployment of water technologies. Due to the expense and long-term environmental impact, it is highly unlikely that RO technologies would ever be used to help rural communities transform brackish groundwater into clean water. Groundwater would remain untapped as a viable source of clean water. We believe the phytoremediation of groundwater sources is a cost-effective, sustainable solution.
Contact the Project Team
Surisa Surisa, Ronel Scheffer, Beth Peterson and Arina Swart.