Cape Town’s water shortage has escalated to the level of a disaster, with the city planning to shut off taps to homes and businesses by mid-July. In order to prepare and inspire other companies, Xylem has installed two innovative systems for rainwater and wastewater use at its office.
2017 was one of the driest years in recent decades in South Africa’s Western Cape region. In addition to low rainfall in 2017, the region had two dry winters in a row. Such severe multi-year droughts are very rare – occurring perhaps once in a millennium – and water supply systems are not designed to withstand their impact.
The hope for a natural solution vanished with the end of the rainy season in September. It is clear now that water storage in the dams will not be enough to supply the city, and it will be depleted before the May-June rains next year. Given the situation, Xylem decided to make preparations at its office to use alternative sources of water.
A system for reusing treated, non-potable wastewater
In order to take pressure off Cape Town’s potable water system, the Potsdam Wastewater Treatment Works has been making treated wastewater available to local businesses. Xylem’s office has installed an effluent point at their premises, where the water is pumped into the building.
The system includes storage tanks, a pump – Xylem’s Lowara BGM11/A 1.1 kW – and pipework on site. From the effluent point, a horizontal 5,000-liter tank is filled and used both for Xylem’s wash bay and to top up its test bay. The effluent water is also used to irrigate the gardens.
The system not only saves water, it also reduces costs. Since the price for municipal water is ZAR 24.54 (€1.63/$2.05) per cubic meter, and effluent water costs ZAR 7.00 (€0.47/$0.58) per cubic meter, the Xylem office spends 70 percent less for the same amount of water.
A second system for treating rainwater for consumption
Two 5,000-liter vertical tanks for rainwater harvesting were also installed on site. With the possibility of Cape Town’s taps soon being turned off, the Xylem team decided to connect their rainwater to a Xylem HydroInfinity unit. This system treats the water with UV and ozone technology so that Xylem staff can use it for drinking water. If sufficient rains come during the rainy season, this will save Xylem staff time since they will not have to collect water at various points around the city.
“Xylem’s HydroInfinity is a chemical-free water purification system for businesses,” says Alfred Fincham, Manager of Xylem’s South Africa Cape Town branch. “It inactivates all pathogenic organisms from the water supply – including E.coli, Salmonella, Legionella bacteria and the Cryptosporidium oocyst – allowing us to turn rainwater into high-quality drinking water. With enough rain, this will assist all our staff with water collection when the taps run dry. It will also serve as a working demo unit for customers to view.”
Since HydroInfinity was installed in September 2017, water consumption at Xylem’s Cape Town office dropped by two cubic meters (from 18 m3 to 16 m3) in just one month. The aim is to reduce consumption down to 10 cubic meters by mid 2018.
“There is still a long way to go, but every little drop counts,” says Peter Wright, Segment Director, Residential & Specialty AWS EMEA at Xylem. “If Xylem can do it, so can every other company in the Western Cape. It might make a small difference individually, but together we can all make a big impact.”
Other solutions that help communities build resilience
As a leading supplier of water technology, Xylem helps communities around the world improve water security and recover from natural disasters. The company’s solutions are creating a more water secure future in places such as Los Angeles, Mumbai and Saudi Arabia.