Can She Lay the Building Blocks to Help the World's Sewage Pay Off? - OZY | A Modern Media Company

Can She Lay the Building Blocks to Help the World's Sewage Pay Off?

Can She Lay the Building Blocks to Help the World's Sewage Pay Off?

By Nick Dall

The world’s first bio-brick, made using human urine, was unveiled at the University of Cape Town this week. Pictured are (from left) the department of civil engineering’s Dyllon Randall and his students, Vukheta Mukhari and Suzanne Lambert.
SourceUniversity of Cape Town


Because if wastewater treatment pays for itself, it would be a revolution.

By Nick Dall

Most bioprocess engineers wear crisp lab coats and work in ultra-clean stainless-steel reactors. While professor Sue Harrison, from the University of Cape Town’s chemical engineering department, is familiar with this sterile world, she’s increasingly drawn to muckier, less controlled environments. For the past 15 years, her focus has been on mimicking nature to challenge the very definition of waste.

Harrison is a pioneer of both bioprocess engineering (putting nature, often in the form of algae or bacteria, to work in industry, cities, businesses and elsewhere) and transdisciplinarity (she’s worked at the interface of chemistry, engineering and the life sciences for more than 30 years). Now, as the director of the Future Water Institute, UCT’s interdisciplinary research center, she is taking both obsessions to their logical extremes in a quest to improve the prognosis for water-starved South Africa, a country that, according to doomsday predictions, could run out of water by 2030.

“In the past, we have considered natural capital as a free good,” she says. Today more and more individuals, politicians and industries are coming to see the flaws in this approach. (One example: Cape Town’s new water strategy refers to significant quantities of reused water being included by 2023.) While it must be tempting to say “I told you so,” the 56-year-old prefers to take advantage of the shift in attitudes to make lasting changes to the way South Africa — and, hopefully, other developing countries — interact with water.

Wastewater actually “contains plenty of value,” Harrison insists.

A primary focus for Harrison and her colleagues, both at the Centre for Bioprocess Engineering Research (a research group she founded in 2001) and at Future Water, is the development of so-called wastewater biorefineries (WWBRs), complex systems that rely on a web of bioprocesses to extract maximum value from wastewater, while at the same time producing clean water. If done correctly, the value obtained from the byproducts (one of her UCT colleagues is making construction bricks from urine) pays for the water treatment — a stark change from the status quo where wastewater is viewed as an “end-of-pipe cost,” she explains, “something which needs to be treated” or else. Au contraire, she insists: Wastewater actually “contains plenty of value,” she says, citing a study she worked on suggesting that municipal wastewater contains enough embedded energy to produce 7 percent of South Africa’s electricity needs through anaerobic digestion and related processes. The catch? No one’s built a fully functioning biorefinery yet.


Sue Harrison tackles South Africa’s water crisis one test tube at a time.

Source Courtesy of Candice Lowin

“If anyone can pull it off,” says Kirsty Carden, research coordinator at Future Water, “Sue can.” The youngest in a family of scientists and engineers, Harrison remembers being fascinated by her chemist-slash-biologist dad’s dinner table chats, which leaped from chemistry to farming to sailing. Her parents encouraged her to study something other than science, but the die had been cast. After completing a degree in chemistry and microbiology at UCT, she took a job at AECI, a leading South African chemicals company looking to advance its biotechnology division.

After several years in the industry, she stepped out to earn a Ph.D. in chemical engineering at Cambridge, where she got to work on a groundbreaking group of new biodegradable plastics, known as PHAs. While back in Cape Town on holiday, she was lured back to UCT — her home for 28 years and counting. Staying in the same place for that long, she says, would be her “worst nightmare,” except that her tenure has been anything but routine. She has worked with “fresh” and waste ingredients in myriad locations (she was in a different country each of the three times we spoke) and applications (biomining, mineral leaching, mine waste and rehabilitation, algal biotechnology, wastewater treatment and more).


Her biorefineries could go a long way toward easing the world’s water scarcity and improving how we use our natural resources, but she’s still figuring out how to make them work.

To take the example of organic wastewater (whether from food processing, the paper pulp industry or people’s homes), Harrison’s first move would be to extract the carbon from the water and repurpose it, most likely as some sort of plastic and/or soil conditioner. Then she’d put the nitrogen and phosphorous through a microalgal reactor (a pond containing microscopic algae) that would create biomass for energy while also taking up carbon dioxide from the atmosphere (good for carbon credits). The “leftover” nutrients could then be used to produce electricity. By this stage the water would be “pretty clean,” Harrison says, though she might grow plants on it “to give it a final polish.”

All well in theory, but finding a middle ground between the sterile lab conditions that bioprocess engineers are accustomed to and the grimy reality of wastewater treatment plants will be “the really interesting part,” says Harrison, “because these two worlds have been so separate; there is no rulebook.”

And that’s before anyone tackles the legislative (are we even allowed to do this to wastewater?) and social science hurdles (will subsistence communities care whether or not their water is compliant?). Not to mention the feeling in some quarters that — as Mike Muller, former director-general of South Africa’s Department of Water Affairs and Forestry, puts it — “poor management and governance are the real challenge [to South Africa’s water problems]. Until that is fixed, technologies and methodologies are of little assistance.”

But rather than let herself be cowed, Harrison is confident that initiatives like hers can push the country forward. In addition to her scientific achievements, says Faizal Bux, director of the Institute for Water and Wastewater Technology at the Durban University of Technology, Harrison has the social skills to keep her multidisciplinary team fighting for a common cause. “Sue’s a straight talker, but she’s very diplomatic,” says Carden — an assessment based on Harrison’s deft handling of interactions among the highly opinionated crew that make up Future Water.

While Bux, Carden and Harrison agree that large-scale application of wastewater biorefineries is far off, the alternative — having insufficient natural resources to sustain the global population — is too dire to entertain. The concept “is not rocket science,” Harrison says modestly. “It’s just a new way of doing things.”

And that is her stock-in-trade.

OZY’s 5 Questions With Sue Harrison 

  • What book do you really value and like to share? Dr. Seuss’ Oh, the Places You’ll Go — lots of truth and inspiration. I started reading it to my children, and now it is a firm favorite gift for my Ph.D. graduates. 
  • What do you worry about?Worry needs to be kept under control, as it is not always positive. … But I do spend a lot of mind space on how to contribute toward transitioning our world into one where we work jointly for our success and the greater good of our communities, cities and fellow travelers. 
  • What’s the one thing you can’t live without? My family — a truly inspirational set who keep me grounded and inspired at the same time. 
  • Who’s your hero? My father. He inspired me on my path between the disciplines of engineering, chemistry, microbiology and biochemistry; set an example of entrepreneurship, integrity and aiming to contribute; and he nurtured me along the way. 
  • What’s one item on your bucket list? As an academic: to see one of my new processes through to full implementation. As a fellow citizen: to see a more just economic order. As an explorer: to see the northern lights.

Read more: He’s creating a new fuel out of thin air — for 85 cents a gallon. 

Sign up for the weekly newsletter!

Related Stories