DPR project in Africa 'cradle of water reclamation'

By Ann Espinola

A handful of water utilities in North America operate direct potable reuse plants, but none come anywhere close to the longevity of the world’s first DPR project -- in Namibia, Africa.

Many water professionals are aware of Windhoek, Namibia, and its place in water history, but perhaps not that it has successfully put out purified water for nearly 50 years – four and a half decades before the first DPR facility in the United States went online in Big Spring, Texas. 

“DPR, in our view at least, is a very viable option for water management in water scarce areas, and in fact has saved Windhoek from catastrophe on more than one occasion, most recently in the 2014-16 drought,” said Pierre van Rensburg, Windhoek’s strategic executive for urban and transport planning, in a recent interview with Connections.

Van Rensburg will speak about the groundbreaking Goreangab Water Reclamation Plant – its history, 10-step treatment process, and ongoing initiatives -- during the International Symposium on Potable Reuse, January 22-23 in Austin, Texas. It is believed to be the first time someone with a direct connection to the plant will travel to the United States to discuss it at a major conference.

The symposium is co-located in Austin with the International Symposium on Biological Treatment, January 24-25.

Public confidence

Windhoek first began recycling wastewater at the Goreangab plant in 1968. More than three decades later, in 2002, the city built a new DPR plant next to the original plant, which is still operating, but produces water only for irrigation purposes.

In all the years since Windhoek first embarked on its historic journey, no illness has ever been directly linked to its DPR operations, van Rensburg said.

“That’s something we are very aware of and try very hard to maintain,” van Rensburg said. “The whole issue of public confidence is that very, very fragile link that keeps the system going. I think if there is ever one incident that could be linked back to the plant, the public would lose all confidence and simply refuse to use water from that source and that would severely taint our supply options.”

Namibia is on the southern Africa border and is the driest country in sub-Saharan Africa. Windhoek, the capital city, receives 14.6 inches of rainfall a year, compared to 30 inches on average throughout the United States.

The Goreangab plant has been called the ‘cradle of water reclamation’ and is believed to be the world’s only pipe-to-pipe DPR facility. It produces purified water for the city’s 400,000 residents that is not treated again at conventional water treatment plants, but instead goes directly into the distribution system.

“The current technology is often criticized for not including reverse osmosis,” Van Rensburg said, “and as far as I know is the only facility not to do so. But we do continuous testing of new contaminants of which the latest have been antibiotic resistant bacteria and genes.”

Van Rensburg recently co-wrote a paper for the International Water Association called “Direct potable reuse – a feasible water management option,” which will be published soon. He expects it will be the basis of his talk in Austin.

The paper provides an overview of major DPR projects in Windhoek; Beaufort West, South Africa; Cloudcroft, N.M.; and Big Spring, El Paso, Brownwood, and Wichita Falls, all in Texas.

Growing interest

There has always been keen interest in the Windhoek DPR facility, but even more so recently as global water scarcity concerns grow. In the last year alone, delegations from many countries visited the plant, including France, Germany, India, Australia, Singapore, the United States, the United Arab Emirates, and Mozambique.

Even locally, “Cape Town in South Africa has a major crisis,” van Rensburg said, “and is knocking on our doors very frequently.”

From its earliest days, Windhoek has been plagued by water shortages. It is far from naturally occurring surface water sources and more than 300 miles from augmentation alternatives -- other than desalination at the coast, which is 230 miles away and a mile lower in elevation.

Windhoek residents are proud of their trailblazing status, van Rensburg said, and have registered few, if any, complaints regarding the city’s drinking water treatment processes.

“I guess back in the 50s and 60s, public opinion, or at least in this part of the world, was not as strongly developed and organized as it is today. Once people got used to (DPR) and nothing happened, we happily carried on.”

Several years ago, the city conducted a survey: 93 percent of responding residents said they only drink tap water and 90 percent said they believe their water is safe to drink.

But what really surprised van Rensburg was the responses to the question, “Do you know where the water comes from?”

“Many said the dam, which is partly true. Very, very few actually knew where the water came from -- only 40 percent or so could actually name that a portion comes from reuse, which tells you a lot of people don’t even think about direct potable reuse. It’s been around for so long. We found that people not born here, or who moved here in the last 10 years, were not aware of the fact that they were drinking reused water.”

Because of that, the city renewed its focus on education and organized tours for local school children and university students.

“It’s a known fact if you can target kids, they go home in the evening and tell the family and everybody what they’ve learned. We show them it is safe and now they know a portion of their drinking water comes from reused water.”

Celebration planned

The city will commemorate its 50th DPR anniversary next year with a two-day celebration in August or September, van Rensburg said. Plant workers from the last two to three decades will be on hand as well as several international experts to discuss the latest research and information on DPR’s future.

Asked what advice he would give utility leaders considering direct potable reuse, Windhoek noted that many managers trek to Windhoek looking for a “quick fix” to their water problems.

“The technology is there. I think the management and health aspects have been sufficiently covered,” van Rensburg said. “But at the same time, it involves a huge commitment after the establishment of the plant. You must maintain confidence with the public. You must make sure health aspects are continually looked after and invest in research and stay abreast of the latest developments. You can’t just put the plant there.”

Over the years, Windhoek has continuously upgraded its plants.

“The plant we built in 1968 would not be accepted today,” van Rensburg said. “We look at what’s happening on the water and technology front and the water pollution front. We monitor quite widely to know who’s discharging what wastewater because there is a good chance if we can’t remove it somewhere along the treatment line, it will end up in the final water product.

“The management of DPR implementation is almost as critical as putting it there. If you can’t make that commitment, or you are in an environment where you know this will probably not be sustainable, I think you should just stay away.”

Do you have a comment or story idea for Connections? Please contact Ann Espinola at aespinola@awwa.org or at 303-734-3454.