Vancouver firm makes fertilizer out of human sewage

A small Vancouver company has developed a process for turning human sewage waste into valuable fertilizer for crops.

"We can produce a high-quality fertilizer from sewage," University of British Columbia Don Mavinic said. "As long as there are people, sewage-based fertilizer will be a renewable and sustainable resource."

Mavinic was part of a research team that pioneered research into how a global lack of phosphorus a nutrient vitalto plants might be addressed.

"Everyone has heard about peak oil," Mavinic said. "[But] soon, you'll be hearing about peak phosphate. It's another major sustainability issue looming on the horizon."

Current estimates predict that the world will exhaust its supplies of mined phosphorus in as little as 35 years. Global demand for phosphorus will outstrip supply in about a decade, Mavinic estimates.

But it's a plentiful element in human waste, so researchers have been trying to find a way to extract it.

Pilot projects in Oregon, Edmonton

This summer, the world's first full-scale phosphorus-recovery system went on-stream in Portland, Ore.'s municipal sewage system. Based on Mavinic's work, Vancouver-based company Ostara Nutrient Recovery Technologies Inc. has been harvesting phosphorus from the wastes of 500,000 Oregonians.

A pilot project in Edmonton using the same technology is in its early phases.

Using human waste to maintain the supply of fertilizers actually came about as a result of work begun by Mavinic and a colleague more than a decade ago to solve another problem: keeping sewage systems clean.

In sewage treatment, phosphorus forms a crystalline compound called struvite that builds up on the inner walls of pipes. It's a bit like hard water buildup on household pipes, and it's a costly problem to fix.

Currently, phosphorus is captured by using chemical binding agents and simply disposed of as waste.

"For decades, we've thought about just removing phosphorus from sewage," Mavinic said. "Now, the paradigm has shifted, and around the world there's a recognition that this is about the recovery of a valuable resource."

The phosphorus collected at the Oregon facility will be collected and sold as a fertilizer called Crystal Green.

It's ideal for any scenario that requires a slow release of nutrients, such as plant nurseries and golf courses.

Mavinic estimates Canada could supply as much as a third of its phosphorus needs simply by recycling it from human waste.