Modern Quarrying

A joint initiative of the City of Cape Town and the Southern Africa Readymix Association (SARMA) is underway to research the effective usage of effluent water to manufacture concrete and concrete products.

Johan van Wyk SARMAUntil now, no specific standards exist to allow the use of water other than “potable” water to be used in the process. However, in light of the recent drought in the Cape Town region, concerned SARMA members have joined forces with Cape Town Municipality to work together to use effluent water that might otherwise ease the water problems in the region.

According to SARMA director, Johan van Wyk, if a suitable solution can be found it will not only have a positive effect on water supplies and the environment but will also reduce the cost of water for construction by as much as 75%.

“In this instance, effluent water does not refer to sewage but rather to water from sewerage plants that has gone through all cycles of treatment except naturalisation in a maturation pond. This type of water is often used for irrigation and is not disallowed according to national standards nor is provision made for it in SANS 51008 water for making concrete because, until now, no specific testing has been done,” explains van Wyk.

“As a result, we are currently compiling a testing which will enable us to run an eight-week study and collate results including chemistry and all the parameters surrounding the water and then monitor its effect on the mixing, setting, curing and strengths of the concrete,” he adds.

“This will then be compared with current concrete standards and data to make a finding. And, it must be said, that our preliminary findings are positive and gives hope for a major evolution in the way we make concrete in dry climatic regions,” says Van Wyk.

The construction industry is a major water user and in the case of concrete manufacture, the industry cannot survive without a reliable supply of water. Where water shortage occurs it can either lead to the closure of concrete manufacturing plants or to manufacturers seeking alternative methods of obtaining water.

 “As guardians of future generations, we feel it is our responsibility to find sustainable alternative means of manufacturing concrete which in turn plays a significant role in shaping our future and building infrastructure for the next generations,” he says.  

“The finding will be made available on completion of the research and best practices will be shared with all concrete manufacturers via internal communications, as well as all forms of media at our disposal,” concludes Van Wyk.

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