New Technology to "Mine" Phosphorus from Wastewater

An innovative process that turns wastewater into phosphorous fertilizer granules is simplifying Oregon’s complicated relationship with this essential nutrient.

On one hand, phosphorus is needed for all living things to grow, said Brett Laney, operations analyst for Clean Water Services, headquartered in Hillsboro.

On the other hand, too much phosphorous runoff can create aquatic “dead zones” and algae blooms, overwhelming wildlife habitats and fouling drinking water.

Clean Water Services, alongside Ostara Nutrient Recovery Technologies, is promising to retrieve that valuable nutrient, while keeping it out of the world’s waters. They pin their promise on innovative technology that creates granules of Crystal Green, the brand name of the phosphorous fertilizer produced at 18 of Ostara’s facilities, two of which are in Oregon’s Tualatin River watershed west of Portland.

Reclaiming phosphorous from wastewater is possible and imperative, said Laney. The world is running out of phosphorus, an essential ingredient in DNA in plants and animals, and a common fertilizer.

Until now, phosphorus was mined from the earth, but mines are disappearing. About 70 percent of the world’s phosphorus comes from a single mine in Morocco, according to Vera Thoss, a chemistry lecturer at Bangor University.

However, most Crystal Green users don’t choose it because of impending shortages, according to Ostara officials. Most clients, including Joni Elteto of Scholls Valley Native Nursery near Forest Grove, say its use is part of the company’s commitment to environmental stewardship.

Recent studies into struvite, the rock-like magnesium ammonium phosphate crystals that form inside wastewater plant pipes during the treatment process, prompted hope that new technology might make use of water treatment’s troublesome byproduct.

Vancouver, B.C.-based Ostara licensed technology from the University of British Columbia allowing them to recover nutrients from any process water stream containing high amounts of phosphorus, turning it into fertilizer.

In 2009, Clean Water Services partnered with Ostara, installing the first facility in the world to reclaim phosphorus from wastewater at their Durham facility in Tigard. Clean Water Services’ second facility near Hillsboro followed.

“Struvite used to be a nuisance,” said Laney of the build-up that for decades had slowed wastewater treatment processes. Now, new processes turn it into a slow-release fertilizer.

The granules don’t dissolve in water; instead the plant accesses the phosphorus by dissolving the granules with its own citric acid, created during photosynthesis. Because Crystal Green is plant-activated, studies indicate the slow-release granules may be better for the environment than conventional water-dissolved fertilizer. The granules reduce waste and runoff when used as fertilizer.

“The agricultural community is buying into it because of the multiple benefits,” said John McDonald, a hazelnut orchardist who is also Tualatin Soil and Water Conservation District’s chair.

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Taxonomy

• Nutrients Recovery
• Nutrient Recovery & Reuse
• Circular Economy
• Phosphorus Recovery