Secondary settling tank at Potsdam Waste Water Works. Picture: Courtney Africa/African News Agency(ANA)
Secondary settling tank at Potsdam Waste Water Works. Picture: Courtney Africa/African News Agency(ANA)

Water-recycling model will hopefully help alleviate Cape’s water stress

By Sukaina Ishmail Time of article published Oct 13, 2020

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Cape Town - Research on a new water-recycling model will hopefully assist policymakers in the City to adopt more sustainable methods of reusing wastewater in the province, which remains water scarce.

The model was developed to allow more people to understand the long-term effects of water retention and recycling in Cape Town’s urban water system which could potentially reduce water scarcity.

Stellenbosch University Department of Industrial Engineering professor Wyhan Jooste said: “Currently, only 5-10% of the wastewater (sewage water) received by the City’s water reticulation system is treated and reused for daily consumption.”

He said that a combination of conservation management, harvesting of rainwater and reusing greywater and treated effluent from centralised and decentralised facilities will help to address water scarcity over the long term.

“Our modelling results provide evidence that policy interventions for retention and recycling of water within the urban water system have the potential to contribute to alleviate water stress over the next 20 years. The results also show that water scarcity in the City requires unique and innovative solutions to ensure economic, social, and environmental sustainability and growth,” he said.

Their research did not cover the effectiveness of the City’s waste-water methods such as whether consumption of water resources was too high or low. It focused on consumption recorded and the future consumption based on the current population and economic growth rates.

Jooste said: “Water from centralised and decentralised wastewater treatment plants, rainwater, stormwater harvesting and greywater reuse are all plausible alternatives to constrained groundwater supply sources.”

They hoped that the research would assist City policy decision-makers with future decisions on recycling and retention of wastewater streams to help tackle water scarcity.

The researchers, which also included the department's Professor Amoré van Zyl, said the results also highlighted the continual rise in water supply stress due to population and economic growth forecasts for the city.

“It is evident from the research that innovative solutions are required to ensure future availability of water to meet the growing demand. The implementation of water retention and recycling initiatives can, however, play an important role in alleviating water supply stress in the future and warrants further consideration.”

Cape Argus

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