Cape Town delays Day Zero

While Cape Town may have avoided Day Zero this year, the city’s water woes are far from over.

Day Zero was supposed to be the point when the city of 3.7 million people ran out of water. A few months ago that date was predicted to be June 4th. Then in March, after weeks of raising awareness and pushing people to use less than 50 litres of water per day, the City of Cape Town came with good news: Day Zero had been pushed forward.

Nevertheless, the city will continue to face a water scarcity and climate change will do little to improve the situation. Structural interventions are needed, starting with how the city and property developers use wastewater, experts say.

“The City projects that Day Zero would arrive on 27 August 2018 if there is no rainfall. As this date falls deep within the normal rainfall period” there is a good chance it will rain, the local authorities said in a statement.

To safeguard its overall water security, Cape Town has developed an action plan which includes the construction of desalination plants.

“These can give us 16 million litres of water per day, and extracting groundwater from aquifers could result in another 120 million litres daily,” Tim Harris of the Western Cape’s trade and investment promotion agency, Wesgro, said during a recent water and technology debate. He noted that the latter was a temporary solution because aquifers need time to recharge.

In addition, 10 million litres daily would come from wastewater re-used and recycled through the Zandvliet reclaimed water plant.

Some say Cape Town should have recycled and reused its wastewater a long time ago, just like Windhoek. Namibia’s capital received 313 mm of rain in 2017, half of Cape Town’s share of 788mm. Windhoek started turning wastewater into potable water 40 years ago when it built the first Goreangab waste treatment and reclamation plant.

“The water goes through quite a few steps, including water filtration, sedimentation, ultrafiltration, reverse osmosis, advanced oxidation and chlorination, before it is sent to the municipal reservoir,” said Pierre Marais of Water and Wastewater Engineering in a November 2017 radio interview. The result: world-class drinking water supplying 25% of Windhoek’s needs.

In the early 2000s, a new plant was built in Namibia with a capacity of 21,000 cubic metres per day. According to Marais, once there is no running water new and innovative solutions are required.

South of Windhoek and 460 kilometres from Cape Town, the semi-desert town of Beaufort West has also started recycling sewage water after it ran out of drinking water last year. It relies on boreholes and recycled sewage water, which supply 20 percent of the town’s needs.

South African technology entrepreneur Mervyn Maistry, who lives in Germany, notes that Artificial Intelligence and other new technologies can help fix Cape Town’s water woes by changing the way it uses and manages its wastewater.

“You can have special sensors that help collect water and test how many impurities your wastewater has,” says Maistry, the founder of Konfid.io, a consulting and incubation company. “This helps your home’s water system decide which wastewater you can use for your garden and your toilet, which can go into the sewage system, and what water you can drink.”

These new technologies can be deployed in a large-scale set-up, he says, referring to San Francisco in the United States. The city has launched a technology-powered sewage monitoring and management system featuring special sensors which cost $2 each and have a lifespan of 15 years. These devices monitor the sewage flowing through San Francisco’s pipes — its velocity, volume, composition and level of contaminants.

Maistry says implementing new sewage technology should go hand in hand with re-examining Cape Town’s booming property sector which uses a lot of water — from construction to the final product. This includes the way the sector treats wastewater. Formal residential areas in Cape Town account for 65% of the city’s drinking water usage.

“Cape Town is experiencing a property boom, with developers getting licenses to build large apartment blocks,” Maistry says. “Few of these are, however, mandated to be self-sufficient in terms of water. If you have such a property boom in which developers are making millions of dollars, get them to install rainwater systems, wastewater recycling systems and toilets that are on a separate plumbing system to drinking water.”