Microbiologists from Stellenbosch University (SU) are piloting innovative rainwater harvesting technologies in the area to alleviate the pressure on municipal water delivery.

Sprawled across the slopes of Papegaaiberg lies Enkanini with its population of about 10 000 residents, but with access to only 36 communal taps. As Brandon Reyneke takes another sample from the small-scale rainwater harvesting solar pasteurisation treatment system installed a few metres outside the entrance to Victor Mthelo's dwelling, he says: "I enjoy the chance to get out of the laboratory and interact with the people involved in the project."

Since September 2015, the 23-year-old Reyneke and fellow students in the water resources microbiology laboratory have been visiting three pilot systems in Enkanini once a month to collect samples and to check if the systems are still functioning. Often they also take time to chat with the families involved. This time Reyneke is alerted to the fact that, during the rainy season, the hole containing the solar pasteurisation system overflowed, with water running down into the shack immediately below.

"Initially we had a hard time finding enough space between the shacks, as well as a level surface, to install the systems," he explains. "The roofs of the shacks are also not strong enough to carry the system."

That is only one of the obstacles the water resources microbiology laboratory, under the leadership of Dr Wesaal Khan, are working on. Her laboratory is currently one of the primary laboratories in South Africa focusing on the treatment of rainwater using solar technologies. The South African government has earmarked rainwater harvesting as an alternative and sustainable water source in rural areas and urban informal settlements. But while the practice of harvesting rainwater has been around for ages, the technology has not kept up with our modern, more polluted, conditions.

"South Africans are familiar with the concept. But while communities in the Eastern Cape routinely use the rainwater for drinking purposes, our research shows that rainwater in especially urban areas is heavily contaminated with chemical and microbial pollutants," Khan explains. In urban areas rainwater becomes contaminated with heavy metals due to air pollution from nearby industrial areas. Micro-organisms from the debris of plants and faecal matter from birds and small animals on the roofs also find their way into rainwater tanks.

She warns that several micro-organisms isolated from rainwater tanks during their trials are associated with diseases such as diarrhoea, pneumonia and worm infections, amongst others. That is why it is so important to develop cost-effective and sustainable technologies to disinfect the rainwater. Khan recently completed a project for the Water Research Commission in which she tested various existing technologies for treating harvested rainwater. The solar pasteurisation method, also called SOPAS, came out as the most reliable and inexpensive treatment system.

Khan's group is now working towards the installation of small- and large- scale rainwater harvesting treatment systems that will provide for the water needs of a group of households in a specific area, or to local schools and clinics. "The idea is not to develop an alternative to the drinking water supplied by municipalities, but rather to supplement existing services. After treatment, the rainwater can be used for washing the dishes, laundry and personal hygiene."

Their research is a combination of applied and fundamental science: "We want to make this technology work so that the community will use it. But we are also trailblazing new molecular methods in rainwater treatment that we are very excited about. We are one of the first laboratories in South Africa to focus on the large- scale monitoring of the chemical and microbial quality of rainwater. The bottom line of all our research efforts, though," she adds, "is to have an impact on the community."

CAPTION: Dr Wesaal Khan explains to Enkanini residents how the SOPAS system works.

• This article is published in the latest edition of the SU magazine, Matieland. Read the magazine at www.sun.ac.za/matieland. You can also register on this website to receive the magazine for free.