- Category: PROJECTS
- Published on 26 April 2016
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By Kelly-Ann Prinsloo
Deep in the heart of the Kruger National Park lies a house known as Dulini House. Dulini House, situated in the Sabi Sand Reserve in the Kruger National Park, is an exercise in environmentally-friendly luxury. From heat pumps to a complete grey water harvesting system, Dulini House is easy on the eyes and its surroundings.
The Kruger National Park is the green heart of South Africa. Stretching across 19 485km2, the Park is home to scores of wildlife and multiple camps, including the Sabi Sand Reserve. This is where you will find Dulini House.
The owner of Dulini, Mick Davis, wanted to create a place where people could enjoy an up-close-and-personal experience with the wonders that South Africa’s natural world has to offer.
Geoff Wade, of Phala Sanitary Engineers, explains that, because Dulini was built in the middle of the Kruger National Park, certain things had to be taken into account, such as waste minimisation, litter, road cleaning, contaminated material, noise pollution and dangerous animals. “These were just some of the elements faced on a daily basis,” says Wade.
“An environmental management plan for the construction site and an assessment to identify which parts of the environment may be vulnerable to damage from construction activities was implemented. And there were frequent inspections and close monitoring of the site by the South African National Parks (SANParks) board.”
Chris Kyle, of Kyle and Associates, was the wet services engineer on the Dulini project, which took about 18 months to complete. He explains that, because Dulini is located in such a remote area, the building’s infrastructure had to be built along with the building itself. “The challenges were to bring the local borehole water to acceptable standards for human consumption. And then it was just a matter of delivering the water to the building, and making sure the greywater is harvested and filtered so that it can be used for irrigation.”
Safe for the environment
The usual safety considerations, like fire prevention, took an unusual turn at Dulini. “The swimming pool serves as the fire pool, and there’s a diesel pump there so that, if there is a fire, water can be pumped out of the pool.” Kyle explains. A fire at Dulini could be disastrous, not only for the building and its residents, but for the environment in which the building stands.
“It’s a very self-contained system,” Kyle says. “It’s out in the bundus, so it has generators. There were green considerations, which included the heat pumps and low-flow settings and grey water harvesting system, which were all included in the design.”
Another unique feature of Dulini is the water filtration system. Bruce Dalton, a chemical engineer from Aqua Media, was called in because the house’s remote location meant a lack of running water. The water from the borehole was so full of calcium and magnesium that it is undrinkable.
“When the water is hard,” Dalton explains. “It’s calcium and magnesium that gives it that hardness. Now, a big problem with hardness is that, if you have a counter-iron like carbonate and sulphates, what we call an anion, it starts to form deposits on anything that heats or cools. We call it scale.
Dulini’s problem, in addition to that, is that the borehole water has a high percentage of total dissolved solids and sulphates. Calcium sulphate gives you a hard scale that is almost impossible to remove.”
What Dalton and his team proposed was to strip out the calcium and magnesium in the water, a process for which a membrane can be used. Dalton explains that the advantage of membranes, especially the particular type of membrane used at Dulini, is it will take 99% of the magnesium and calcium out. “Now, once you’ve removed it, the counter-iron cannot precipitate because the calcium and magnesium are not there. “
“The other advantage is that you get a reduction in the total dissolved solids. So, in Dulini’s case, they are getting a conductivity of around 71 or 72 microsiemens per centimetre. This means that they are getting a total dissolved solids of approximately about 55-60ppm (mg/ℓ). Now, if you think that you started off at about 1800 or 2000ppm (mg/ℓ), and now you’re getting down to 60 ... That’s like bottled water, folks.”
Read the full article on page 14 of our digital version of Plumbing Africa May 2016