mitigating the challenges From load-shedding to water-shedding:

South Africa stands on a precipice in terms of its ability to deliver energy, clean water and safe sanitation to communities and industry.

By Dr Gunter Rencken, technical director, WEC Projects

In addition to challenges faced with ageing equipment and poor maintenance, water and wastewater infrastructure is also affected by regular load-shedding, and subsequent ‘water-shedding’, which can damage pumps, control and instrumentation systems. Water levels in reservoirs also drop to unacceptable levels in areas where prolonged power outages occur, impacting both industry and communities that rely on them.

One way to mitigate the negative impacts of the country’s current water and sewage situation is for industry and communities to reduce their water footprint.

From the start, large-scale water users operating treatment plants need to assess their overall water losses. For example, in South Africa, it is estimated that there is a 40% difference between what municipalities bill for water consumption and what they produce. This imbalance is – by and large – the result of water leaks and theft. Solving this problem alone can result in huge savings and an overall reduction in water footprint.

This reduction in wastage, however, should go hand in hand with other low-tech, point-of-use solutions such as flow reducers and low-flow taps, showers and toilets, as well as more high-tech interventions like smart meters designed to monitor water usage and react under circumstances of abnormally high consumption and inconsistent water flows.

A key response for mitigating the effects of water-shedding is the use of backup water supply systems. This solution is ideal for industrial users reliant on set production levels, as it reduces downtime and production losses. A properly designed and maintained reservoir could provide up to three days of backup water supply – more than enough to cope with the worst water-shedding scenarios.

There are also alternative water supply solutions such as boreholes and rainfall harvesting that can be bolted on to these backup systems, reservoirs or existing water and effluent treatment plants. The greywater extracted from these sources can be treated to the required standards (from industrial and irrigation standards all the way to potable drinking water standards) and fed back into the production supply.

Alongside the issue of potable water losses and interrupted supply, sewage overflows are a regular occurrence across the country, requiring an urgent mitigation response.

One solution is the NEWgenerator™ sanitation system, developed by the University of South Florida and built under licence in South Africa by WEC Projects under the Water Research Commission’s SASTEP programme.

NEWgenerator is a compact, portable and modular sewage treatment solution that can be built into a standard shipping container. It incorporates an anaerobic digester to treat the sewage by breaking down microorganisms to produce biogas. Clean water is filtered out, with bacteria, viruses and any remaining solid particles removed, and then disinfected through a chlorination system. Up to 99% of the water can be recycled for reuse as flushing water for toilets.

NEWgenerator has been thoroughly tested in South Africa and its first commercial installation has already been deployed at a school in the Eastern Cape. The first-generation unit can handle waste for up to 120 users, while the latest version can be scaled up to handle as many as 1 350 users. As a further plus, the system can be designed to run on grid power or solar energy, helping to further mitigate load- and watershedding risks.