Just as loadshedding has seen a proliferation of alternative power solutions, we now have to consider alternative methods of supply, treatment and use of water to counteract the effects of “watershedding” where the ability to deliver clean water reliably and to process sewage effectively have been negatively impacted. In addition to challenges faced with aging equipment and poor maintenance, water infrastructure is also affected by regular loadshedding which can damage pumps and 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. Similar problems are experienced by industrial and residential users and 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 solutions such as smart meters designed to monitor water usage and react under circumstances of abnormally high usage and inconsistent water flows.
Another solution for mitigating the effects of watershedding is the use of backup water supply systems. This solution is ideal for industrial users reliant on set production levels as it reduces downtimes and the resulting 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 watershedding 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. This not only provides an emergency backup in the event of watershedding, but also reduces the user’s ongoing water costs.
These solutions not only offer a back-up plan for water users but also reduce the pressure on municipalities to supply clean water and treat effluent.
The production of biogas (containing methane), a by-product of sewage treatment and certain industries such as livestock farming, is another area which can help mitigate loadshedding. Biogas can be used to power industrial processes, helping to keep the lights on during power outages or, if sufficient volumes are obtainable, allow users to move partially or completely off grid.
Community-level water management
Due to a number of factors such as historical imbalances; lack of maintenance on aging infrastructure; and skills shortages, many communities in South Africa are facing a water crisis. Sewage overflows are a regular occurrence across the country and both formal and informal settlements, many of which lack even the most basic services, are often the most impacted. One solution, developed by the University of South Florida and built under license in South Africa by WEC Projects under the Water Research Commission’s SASTEP programme, is the NEWgeneratorTM sanitation system which can provide proper sewage treatment and managed water usage and recycling for areas lacking conventional infrastructure such as communities utilising pit latrines and portable toilets. NEWgeneratorTM 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. The nutrient rich treated waste is an ideal crop fertiliser for use by local small-scale and informal farmers, and the biogas produced can be utilised for domestic purposes such as cooking etc. The system can be designed to run on grid power or solar energy.
NEWgeneratorTM was thoroughly tested in South Africa and its first commercial installation has already been deployed at a school in the Eastern Cape. The first generation of NEWgeneratorTM can handle waste for up to 120 users while the latest generation of the technology can be scaled up to handle as many as 1350 users.
Solutions for water treatment and energy
WEC projects is an EPC contractor specialising in water and wastewater treatment. It offers a range of solutions designed to help mitigate the effects of loadshedding and the crisis facing the country’s water and wastewater treatment systems. From standardised “package” plants to custom engineered solutions, the company can provide an end-to-end service for water and effluent treatment, recycling, usage reduction, backup supply and alternate water systems, energy production as well as operation of new and existing plants, from initial assessment and design through to manufacture, installation and maintenance. Additionally, WEC assists in water optimisation solutions for smaller communities, housing estates, businesses and municipalities.
Just as many users are moving away from the power grid to independent power generation to avoid loadshedding, many users are beginning to recognise the value in becoming partially or fully water independent through proper usage management and purpose-built solutions designed to reduce their overall water footprint, reuse water and ensure optimum production levels.
By Dr Gunter Rencken, Technical Director of WEC Projects