Vodacom implements state of the art rainwater harvesting project at Midrand Head Office

Submitted by: Tholakele Nene, Wednesday, May 22, 2013

<p>Communications company Vodacom has built a R4.2 million rainwater harvesting system to cool down the company’s air conditioning system and to reduce the company’s reliance on municipal water (Image source: Vodacom).</p>

Communications company Vodacom has built a R4.2 million rainwater harvesting system to cool down the company’s air conditioning system and to reduce the company’s reliance on municipal water (Image source: Vodacom).

Vodacom will now harvest 1 million litres of rainwater per month at their Midrand Head Office from their newly established rainwater harvesting project. The project was established to reduce the company’s dependency on municipal water and to align themselves with local government initiatives, such as Joburg’s Growth and Development Strategy 2040. The water harvested will mainly be used for cooling down the company’s air conditioning system at the Vodacom Commercial Park building. The water will also be used to irrigate the company’s gardens on the Vodacom Commercial Park premises.

According to Vodacom Executive Head of Division, Thembani Jwambi, the R4.2 million rainwater harvesting system has a storage capacity of one mega litres and is expected to harvest 12 million litres per annum on average from an estimated 537mm of annual rainfall. The rainwater will be collected in a storage dam with a total access area of 0.04 km2. Expanding on the specifications of the rainwater storage dam Jwambi adds: “The roof is fitted with a bio-filter and on top of that there is a water wise garden with indigenous plants… the irrigated water from the garden is also drained into the dam.”

From this project Vodacom hopes to save R228 000 annually, says Jwambi. Regarding the projected payback period Jwambi said: “If the City of Johannesburg’s yearly increase was to be 15% then the payback period will be six years. However, if municipal year on year percentage increase is more the payback period will be less.”

Monitoring water quality

Commenting on the quality of the water collected by the rainwater harvesting system Vodacom’s Chief Officer of Corporate Affairs, Maya Makanjee said: “The rainwater harvesting project has been integrated with a central control automation system that allows for continuous monitoring of both water quality and quantity.” Makanjee also highlighted a unique feature of the system, “The rainwater harvesting system has been fitted with a non-return valve to prevent rainwater contamination with municipal water and this feature makes it unique.”

Indigenous gardens

Another water saving project that Vodacom is currently running under the R4.2 million budget is the implementation of water wise gardens which have replaced the former ponds and water features. Due to their large surface areas the ponds and water features had high evaporation rates which resulted in unnecessary water loss. Indigenous plants consume less water and require less maintenance.

Environmental impact of the system

The rainwater harvesting system will divert approximately 1 million litres of water per month that would normally be released from the site. Jwambi states that it was important to understand the environmental impact of reduced runoff on the areas around the Vodacom site. “Special care was taken to ensure that existing riverine and wetland areas and associated fauna, flora and biota are protected from the effects of reduced runoff through rainwater harvesting. Further, the possibilities were investigated for rainwater harvesting systems to contribute to sustainability of such areas through timed releases during periods of low flow.”

Jwambi added that it was found that the Vodacom Rainwater Harvesting system had a minimal environmental impact to ecosystems downstream. “Areas further down receive runoff from progressively larger areas; therefore the reduction in runoff through an upstream rainwater harvesting system was found to be progressively smaller [in] proportion to the total runoff available to a wetland or riverine.”

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Tholakele Nene