Ten years ago, the Greater Vancouver Regional District (now known as Metro Vancouver) http://www.metrovancouver.org/Pages/default.aspx brought UBC Civil Engineering Professor Don Mavinic a costly maintenance problem—wastewater-treatment pipes clogged with a crusty sludge. At the time, he had no idea the pipe held the basis for a solution to one of the world’s most critical challenges—phosphorus depletion.

Although “peak oil” dominates the news as the most critical challenge we face in the 21st century, phosphorus depletion will have a catastrophic effect on the world’s food supply. Mined sources of high-quality phosphorus, an essential nutrient for plants and animals (the “P” in NPK fertilizer), are expected to run out in the next 30 to 40 years.

“I’m not concerned about peak oil,” says Mavinic. “There are alternative forms of energy. But there is no alternative to phosphorus. Life—our life—depends upon it.”

In his quest to solve Metro Vancouver’s costly problem, Mavinic performed a chemical analysis and found that the crusty sludge was composed of MgNH4PO4· 6H2O, or magnesium-ammonium-phosphate, known commercially as the mineral struvite.

At about the same time, Mavinic received funding from BC Hydro's Strategic Environmental Initiatives Program (SEIP)  and, along with Research Associate Fred Koch and BC Fisheries http://www.agf.gov.bc.ca/fisheries researcher (and former grad student) Ken Ashley (MASc ’89, PhD ’02), began investigating sustainable sources of phosphorus to restore degraded productivity in hydro-influenced rivers, lakes and reservoirs in British Columbia. Because reservoirs fluctuate widely in elevation, they lose their near-shore insect production due to freezing and desiccation, trap nutrients and block salmon migration, which are natural sources of phosphorus.

Consequently, hydro projects that involve reservoir formation and river damming mean that many reservoirs, rivers and lakes eventually become depleted in phosphorus and require nutrient replacement to support the natural diversity and abundance of aquatic life, and terrestrial food webs via salmon carcass-scavenger linkages.

The convergence of these two challenges aligned a source and a need, which led to the discovery of an innovative system for recovering and recycling phosphorus from wastewater.

“I didn’t know much about these chemical reactions at the beginning. It took a team of us to figure it out,” says Mavinic. “I called on Professors John Grace from UBC Chemical and Biological Engineering http://www.chbe.ubc.ca and Noboru Yonemitsu from Civil Engineering http://www.civil.ubc.ca/index.php to draw on their expertise as we developed a fluidized bed reactor to extract phosphorus from wastewater.”

In their system, wastewater pumps upward from the base of the reactor, which looks like a stack of four giant kitchen funnels(see illustration on facing page). It agitates by in situ turbulent mixing and “struvite crystals magically form,” says Mavinic.

A self-admitted tinkerer with a childlike curiosity, Mavinic constantly questioned the design along the way: “What if we add another chamber here? How will that effect the mixing and pH balance?”

In the final design, a bit of magnesium chloride and sodium hydroxide added to the mix helps optimize the process. Small pearl-like struvite pellets suitable for agricultural applications float, while larger pellets, desired by BC Hydro and BC Fisheries, sink to the bottom of the reactor.

In 2003, the research team began working with UBC’s University-Industry Liaison Office and filed a patent with Mavinic, Koch and Yonemitsu, along with graduate student Ahren Britton, named as inventors.

In May 2005, a UBC spinoff company was formed.  Ostara Nutrient Recovery Technologies Inc. http://www.ostara.com commercialized the technology through its Pearl® Nutrient Recovery Process. Pearl reactors have been piloted at wastewater treatment plants across North America and used in trials across the globe. A single reactor can produce more than 500 kilograms a day of high-quality Crystal Green®, the fertilizer marketed by Ostara.

“Plants love it,” says Mavinic. “It’s ideal in that it sits on or in the soil until plants need it. Then they drink it in.”

The slow-release nature of the pellet fertilizer virtually eliminates runoff of phosphorus into the water system, providing a fertilizer that is environmentally friendly both in terms of how it is created and its impact.

Removing phosphorus from wastewater can also prevent environmental catastrophes. An overabundance of phosphorus causes algae blooms in lakes, streams and oceans, depleting the oxygen supply and killing aquatic life.

“Balance is the key,” explains Mavinic. “Phosphorus is essential for life, including aquatic ecosystems, but too much will choke water life. That’s why it’s called a ‘limiting nutrient.’”

For wastewater-treatment plants, struvite encrustation has traditionally been a costly nuisance. But thanks to the implementation of the UBC-generated technology, the Pearl Nutrient Recovery Process saves wastewater-treatment plants about $100,000 a year in cleanup costs.

This past fall, Mavinic received two major national innovation awards: the Ernest C. Manning Awards Foundation’s Dave Mitchell Award of Distinction http://www.manningawards.ca/index.shtml; and, with industry partners Ostara, EPCOR Water Services Inc. http://www.epcor.ca, Metro Vancouver, Stantec Consulting Ltd. http://www.stantec.com and Clean Water Services http://www.cleanwaterservices.org, the Natural Sciences and Engineering Research Council of Canada http://www.nserc-crsng.gc.ca/index_eng.asp (NSERC)’s 2010 Synergy Award, for trailblazing research that led to industry partnerships and economic development.

The research has formed the basis for more than 15 master’s and three PhD theses over the past decade. The support of BC Hydro, NSERC, Metro Vancouver, Stantec and Ostara has been crucial to the development of the technology, along with the support of numerous municipalities, including Penticton, Metro Vancouver, the City of Edmonton and Clean Water Services from Oregon for providing testing environments for the reactors supporting the development of the technology.

Mavinic feels that this is only the beginning of what’s possible for phosphorus recovery. Livestock—which excretes 18 to 20 times as much phosphorus in waste as humans—presents a greater untapped resource. Along with UBC Civil Engineering Professor Victor Lo and colleagues in the Faculty of Land and Food Systems http://www.landfood.ubc.ca, the team is testing peroxide microwave technology, which removes nutrients and sequesters valuable carbon (available for methane production) from pig and dairy waste. The patent-pending microwave technology is also licensed to Ostara.  “It’s a fundamental shift in how we view waste,” says Mavinic. “It’s not a problem, it’s a resource. It’s a plethora of possibilities.”

Reprinted with permission from: Ingenuity, UBC Faculty of Applied Science