Windhoek shows the world how to recycle sewage water
‘Remember, October first is run dry day.” The news bulletin ends and Beyoncé’s Formation tests the tinned sound of the rented car’s speakers. A convoy of fuel trucks blocks the road north, from Windhoek to Angola.
Warm air floods through the window. Mountains and thorny acacia crawl past. Here, vast distances are either covered at 80km/h or in a suicidal application of the accelerator. The radio hosts joke about South African politics, and talk about the new Super Rugby season. In arid Namibia the goings-on south of the Orange River are top of the agenda. This isn’t reciprocated, much to South Africa’s cost. Especially during a drought.
That talk of the run dry day, when Windhoek’s three dams are empty, has brought us to a gravel turnoff an hour north of the capital.
A thick chain blocks further progress, keeping people out of the S Von Bach Dam at dawn. On the horizon, the orange sun rises over Botswana. The worst El Niño on record and that unrelenting sun have fuelled a two-year drought across Namibia. The dam is at 23%. On the 1 700m high plateau of central Namibia, dam levels drop 13m a year from evaporation alone.
A booze-cruise boat sits, marooned, on the high-water mark. Its name, Serenity Star, is starting to peel off its fibreglass cover. Further west, Swakoppoort Dam is also at 20%.
For Windhoek, home to Namibia’s industry and 20% of its 2.3-million people, this is an intractable problem. NamWater – the national utility – says the city has six months of water left.
Drought isn’t new to this country, but this one is testing its ground-breaking water technology. The sun and cold Benguela current mean average rainfall is 370mm a year, 100mm less than South Africa. The only consistent rivers form its northern and southern borders. The rest only flow when it floods. Now, they look like lazy brown snakes with full bellies, lounging on a parched and cracked countryside.
Sunrise photographs in the bag, we cross several of these on the way back south – rivers with German names but with no water in them.
We cycle through the English, Afrikaans, German and Oshivambo radio stations. A storm builds up. Lightning forks across the horizon. Clouds knock up against the hills that crumble together to form the bumpy basket that cradles Windhoek. The clouds are teasing. A few fat raindrops fall.
To get a view of the city of 350 000, we head up one of the many steep, winding roads to a cluster of cement water towers behind the main business strip. This necessitates an open-windows-no-aircon philosophy as the car struggles upwards.
From here Windhoek takes the shape dictated to it by the hills and narrow valleys. Its business centre, with three parallel streets thronged by medium high-rise buildings, sits where the original town sprang up. To the north, the glint coming off zinc roofs signals the rapidly growing township of Goreangab. The south is similarly new, and growing. But there the development is high-end – townhouses and complexes that seem copy-pasted from Cape Town.
Natural fountains are what first attracted settlement in the 1800s. These drove the city’s constant growth, until it became the capital of South West Africa – a German colony until it was handed over to South Africa as a protectorate. But in the 1960s these fountains abruptly ran dry.
Water levels at the S Von Bach Dam are dangerously low. (Photos: Delwyn Verasamy, M&G)
Faded photos in the city’s small but monolithic library show the tripods of drilling rigs plastered across the landscape. These could drill to 80m. Now their successors can go to 400m. Neither could find water. Three dams were planned, but would take a decade to build. With the Atlantic 400km away, the city’s planners realised that they would have to manufacture water.
“When you have no other options, people will accept what you put on the table.” Pierre van Rensburg, one of Windhoek’s chief engineers, is taking us back north in his bakkie. Athletic, he sits upright in his seat.
The only viable solution in the 1960s hadn’t been used anywhere else in the world – taking water directly from the sewage treatment plant and treating it more so it could be safe enough to drink. Most treatment plants take their water from rivers. These are downstream of sewage plants yet people find this more palatable.
“What we did removed the middle steps and created a closed loop,” Van Rensburg says.
That plant started cleaning water in 1968, and it still stands on the slope of a hill half an hour northwest of the city centre. The new plant, built in 2001 as demand increased, is just over the rise from the old one.
Learning from 30 years of running the old plant, the new one is a masterpiece of simple engineering. Everything flows downhill – saving energy – through large flotation ponds and aeration tanks. The skeletal metal frames that cover the ponds ensure the atmosphere is dark, but not stuffy.
A team of plant technicians dig more vigorously to remove waste in one of the ponds, sweating for the camera. The only other noise comes out of rooms with thick cement walls, where oxygen hisses.
The different steps in the process disturb, swirl and bubble the sewage until the last few pollutants are caught in carbon membranes 400m downhill. The water that comes out is clean, and is constantly audited.
Pierre van Rensburg, one of Windhoek’s chief engineers, in the town’s meticulously managed Goreangab Water Reclamation Plant.
Van Rensburg speaks in sentences laden with technical details, but in a way that leaves you understanding each step. “People have always tried to catch us out so they can say reusing water doesn’t work.”
He came to the plant as an intern, expecting to make coffee, and ended up working alongside its chief engineer. He speaks about the Goreangab Water Reclamation Plant in a proud and forceful tone. “This whole thing is on stilts. We can’t have one slip-up because just one illness will have serious repercussions.”
Those repercussions could scupper a technology that has always fought an uphill battle to be accepted. Namibia’s pioneering plant has been adopted in three cities in the United States and to great effect in Malaysia.
But elsewhere public opinion has stopped projects. A multibillion Australian-dollar plant in Sydney was powered down just before it could start working, thanks to a petition. South Africa has one working plant, in the Western Cape town of Beaufort West.
An attempt to build two plants to supply water-starved eThekwini in KwaZulu-Natal was met with ardent opposition. This would have blended 10% treated water into the city’s supply. But locals cited religious objections, the “yuck factor”, and a belief that other sources of water could be found instead. Municipal water engineers from the city, and Johannesburg, tell the Mail & Guardian that there is very little they can do about “irrational fears”.
As a result, South Africa’s water and sanitation department is turning to desalination plants. These produce water at double and triple the cost of conventional sources. Windhoek’s plant sells its water at N$11 a cubic metre. NamWater charges N$16 a cubic metre.
Namibia gets around this “yuck factor” through education. Standing in the control room – one technician, three chairs and nine screens run the plant – Van Rensburg says at least one school group comes on a tour of the plant each month. “It’s best to get them early, when they’re still interested in how things work, and not their phones.”
These tours mean, when pupils go home, one child will talk to five or six adults. Namibia’s curriculum also includes dedicated environment classes for teenagers. An agriculture textbook shows the prevalence of lessons about the country’s water reality.
Taking his black-rimmed glasses off to stretch his eyelids, Van Rensburg says a lack of other choices helps hasten people’s acceptance of reusing sewage. “People move here and at first they’re disgusted and have shelves full of bottled water. But a few months later you find those bottles disappearing. It just takes time.”
Sewage is filtered in a process involving carbon pellets at the Goreangab Water Reclamation Plant. After the completion of a cycle, workers clear the pellets from the tanks. At the end of the process, the residents of Goreangab township have access to clean water.
The path of that reused tap water is mapped in a black-and-white aerial photo from the 1960s, nailed to a wall in the plant’s tiny reception. The series of bridges and pipelines going back into the city stand out in the photo against arid bush. Now they have been overwhelmed by Windhoek’s boundaries continually spilling over into virgin earth.
Goreangab’s pipe ends in the city centre, where it mixes in a one-to-three ratio with a pipe from NamWater. Between a quarter and a third of the water coming out of each tap therefore left the city through a sewage pipe.
But even this is threatened by the drought crippling Southern Africa. Less water is being used so less wastewater is available for the plant.
The uncertain future brought on by climate change is a reality. The state water utility’s records show that Windhoek’s three feeder dams overflowed once in the 1970s, and again in 2006. Since then, water has poured over their weirs three more times. In 2012 and 2014 no water flowed into the dams and only a trickle has gone in this year.
The country’s rapid rate of evaporation means what little does go in is almost immediately sucked back into the sky. Windhoek’s solution to this was scrapped during the floods of 2009, but is being quickly resuscitated because of the drought: the giant aquifer under the city will fill with water during times of plenty, giving it 18 months of storage during a drought. Planning documents say this will be fully operational by 2019.
A similar solution is impossible in South Africa, despite similar rock formations, because extensive mining has irreparably polluted most aquifers.
A kilometre above Windhoek’s aquifer, on a surface cluttered with slow-moving midday traffic, we head to a meeting at Democracy House. It sits on a slight hill half a kilometre from Windhoek’s first shopping centre – built in the heady days of freedom in 1990. The house’s entrance is at the bottom of a slope, demanding that we climb a grand staircase to gain entry.
Lesley-Anne van Wyk, co-ordinator for the Environmental Awareness and Climate Change Project at the Hanns Seidel Foundation Namibia, is waiting behind a large Mac screen. We’re late. She lets us off the hook, but gets her revenge by handing over a heavy pile of reading material – homework. We head to a conference room with rows of plastic chairs and narrow desks. A slight breeze flaps the white curtains.
“It’s great to have someone from South Africa interested in Namibia. We don’t get it often.” Van Wyk sits across the table and opens her blue A4 notebook. “We have a lot of interest from overseas. But it’s almost like other people know more about our cool technology than we do locally.”
She pauses on the “cool”, looking up and to the side, before opening her mouth in a thoughtful smile. “Water is obviously – finally – topical in Namibia because we are staring at the cliff’s edge.”
The country is bedevilled by that most basic of human tendencies to worry about problems only when it’s too late to solve them, she says.
“You see this in the construction industry. Windhoek is in the middle of the country, far from water. But we keep growing at an unsustainable rate.”
Other people have mentioned the “great construction boom” as the biggest user of water. Van Wyk says this is driving an economic bubble, but one seen as necessary to keep the economy ticking along. “Sadly water always ends up as the last thought in government planning.”
She stops to write in her notebook. “Things have to go wrong before people fix them, sadly. But we have so much innovation here that we always seem to solve our problems.”
A day later and we’re sampling the local beer. Three large mugs filled with gold-coloured Windhoek are pulled to their corners of the table.
We’ve managed to snag a radio presenter for drinks, someone to give us an overview: “It’s human nature to think disaster won’t happen again.”
The conversation keeps stopping as thirsty swigs are thrown back – it makes a pleasant change from the heavy-tasting Windhoek tap water. Although it’s clean, it doesn’t have the crisp, light taste of Johannesburg water. But that’s a familiarity thing.
The bill comes; despite being linked to the rand, some things in Namibia are pleasantly cheap. Taking a last swig, he says: “We’re in a better place than our neighbours – better off than you are – because we’ve moved past the problem and are willing to accept the solutions.”
The next morning there is good news on the radio. Enough rain fell last night that Von Bach’s water levels increased by 0.2%.
Run dry day might be pushed back.
This story was made possible through a grant from the Wellcome Trust, disbursed by SciDev.Net.