MechChem Africa February 2018

⎪ Water and wastewater processing ⎪

A race to spare every drop of water According to Tjaart van der Walt, director of AVK Holdings Southern Africa, this will not be the last drought cycle in the Western Cape and steps taken now will need to go a long way towards securing alternative water sources and resilience for the immediate, short-term and the longer-term future. “ W hile there is certainlyna- tional and even interna- tional awareness of the watershortagesituation pressure to strictly manage what resources remain,” he adds.

This is not a phenomenon in the Western Cape only, as the region is one of six Mediterranean classified areas across theworld that is experi- encingdrought patternswith signifi- cantly below average rainfall. Such drought cycles can last for years, and thiswill not be the last drought cycle,

and restrictions being implemented in the WesternCape, what is lacking iswidespread acceptance and appreciationof the urgency of the situation,” says Van der Walt. Average dam levels in theWesternCape regionare sitting at 26%(January28, 2018). “In 2016, these levels were closer to 68% – excluding sedimentation in the dams. Less rainfall in critical catchment areas has also intensified the situation during the 2017 winter rain season. “Without further significant out of sea- son rainfall over the summermonths, which cannot solely be relied on to recharge the catchment areas, or alternative access to water sources, evenwith hugewater saving measures being employed, the region will runout ofwater before the2018winter rain season,” he predicts. “While water resources in the Western Cape are in a critical state. However, this cannot be attributed to poorly maintained infrastructure, as the condition of reticula- tion and non-revenue water management in the region is better than the rest of the country and on par with global best standards. It also cannot be attributed to lack of foresight and unexpected changes in the rainfall patterns for the region, as these were forecasted years ago,” says van der Walt. “Simply put, we hoped for rain and took too long to respond. Action should have been taken sooner, not only in terms of driving awareness to save water and implementing water restrictions, but also to invest in alternative supplies of water. Now, and given the state of emergency, the Cape Town City Council is under immense particular the reduction of largest cost ele- ment, electricity. Photovoltaics are now three times more efficient. Aerial Wind Energy (AWE) using principles such as tethered drones, is on sale for the first time in 2018, which is more af- fordable, versatile andmore rapidly installed than ground wind turbines. There are many new forms of waterpower being trialled, such as wave power systems that are viably

leak and pressure dedication technology, with the aim of improving non-revenue wa- termanagement even further. However, one of the biggest challenges remains to reduce water consumption toas lowas possible. For instance, of the 600 M ℓ /day consumption target, single residential houses use 65% of this water – not by industries or busi- nesses as might be expected. Some single residential houses are recorded to be using more than20000 litres of water permonth. To address this, the local municipality in Cape Town is also looking at installing 70 000 smartmeters, whichwill provide for more accurate assessment of and control over water usage. “The water crisis will continue to have a negative impact on businesses, industries and the general economy of the Western Cape and, as a result, the percentage con- tributed by the region to the country’s gross domestic product (GDP). Added to this, because of all the investment into securing alternative water resources for the future, the cost of water in the region will become moreexpensive,addingcoststobusinessand citizen consumers, alike,” says van der Walt. “We need to accept and appreciate that the road ahead will be a difficult one and that, even once the alternative water sup- plies are on board, it will take some time for the natural and economic ecosystems to make a full recovery,” he urges. q The report argues that increasingly popu- lar mobile desalination plants can double as transportsystems,provideelectricityforfarm robots and somewill replace increasingly un- affordable diesel gensets that nowhave to be expensively modified to meet new emissions standardsandremaindependentonailingfuel supply systems. The report is available for download at www.IDTechEx.com/desalination

making steps that are taken now vitally important for securing alternative water sources and resilience, to spare the region from future potential water crises. According to van der Walt though, cur- rent efforts by the Cape Town City Council must be commended. “The Council has planned to spend upwards of R3.3-billion in urgent alternative water supply projects to remedy the emergency situation and se- cure resources in the region for the future, though it will take at least a year before the regionwill feel the impact of these contribu- tions,” he notes. New build water projects underway as part of this emergency plan are focused on three possible supply streams: drilling for groundwater; recycling of wastewater; and seawater desalination. “Recycling of waste- water and desalination, in particular, offer immense opportunity to secure alternative water resource. For instance, currently only 9% of the wastewater is being recycled in Cape Town, but if we look at a city such as Windhoek, the city is totally dependent on recycled wastewater. “Similarly, Dubai only uses desalinated water.Weneed to recognise thepotential to increase the capacities of these alternative water supplies on a much larger scale,” says van der Walt. Parallel to these new project invest- ments, theCouncil is investigatingadvanced downsized, sufficiently rugged and resistant to marine growth. This abundant local elec- tricity source can power irrigation pumps as well as desalination plants. Some off-grid zero-emission desalination systems will be part of village, island and ship microgrids. Market breakdown is included in the report, along with future desalination options and why some technologies are dying out.

February 2018 • MechChem Africa ¦ 33