Office bathrooms could be key to reducing water demand
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A study at the Stellenbosch University Business School (USB) found that in one office building alone in Gauteng, yearly water consumption and associated costs was cut by 87% simply by addressing a major leak, introducing efficient toilet flushing mechanisms, and installing smart metering to monitor and manage consumption.
USB MBA graduate Gerrie Brink investigated the potential of the commercial sector, given its large draw on municipal water resources, to reduce its demand by eliminating inefficiencies.
Office buildings consume almost half the municipal water supply, although they make up just 10% of customers, with office bathrooms responsible for up to 90% of a commercial building’s consumption and also the greatest source of leaks and inefficient water use.
“The cumulative efforts of individuals can make a significant impact, as seen in the results of water-savings campaigns during the recent drought in the Western Cape, but getting large commercial consumers to reduce consumption significantly by eliminating waste and increasing efficiencies can have a quicker impact on our country’s water crisis. And it makes business sense,” Brink said.
Using smart water metering and data logging, Brink monitored water consumption of 30 office buildings in Gauteng and the Western Cape to understand usage patterns and identify inefficiencies, leaks and opportunities for savings.
In the case study of the Gauteng office building, he said 55% of annual consumption of 21 814 kilolitres was lost to a leak.
Once the leak was fixed and smart metering, efficient flushing mechanisms and pressure-reducing valves were installed, the building’s annual water consumption dropped to less than 3 000kl - resulting in a water bill of under R100 000, and a cost saving of more than R600 000.
Brink said the main contributors to water consumption in office buildings were canteens/kitchens, irrigation, cleaning services and air-conditioning, with toilets by far the biggest consumers.
“Because toilets contribute the most to wastewater infrastructure, reducing the wastewater into the system would enable treatment plants to operate more efficiently and discharge less effluent into the environment.
“In short, lower consumption generates less waste. Government and municipalities save on reticulation and wastewater treatment costs, savings that can be used to maintain current infrastructure. The end user saves money. The environment recovers.”
Meanwhile, the Department of Water and Sanitation said it was pleased with the slight rise in dam levels and the prospects of significant rainfall across the Western Cape this week.
According to department spokesperson Sputnik Ratau, the SA Weather Service had predicted heavy rainfall across the province, in particular across the mountainous areas, from yesterday afternoon.
Ratau said there was a slight but not significant increase in the Western Cape Water Supply System, which comprises the six largest dams in the province. The system is currently at 45.78% compared to 45.70% last week.
“The fact that dam levels are stabilising should not be a reason to be complacent. There should be increased vigour to continue with water-saving initiatives,” Ratau said.