From the sewer to the farm, via startup Ostara

Agriculture — done efficiently — can begin and end at a local sewage treatment plant. Canadian startup Ostara¬†Nutrient Recovery Technologies has just finished building a new phosphorous-harvesting plant in the United Kingdom, its first in Europe, at one of water utility Thames Water’s wastewater treatment plants in Slough, Berkshire.

Why should you care about phosphorous? The element is a key ingredient in fertilizers because it helps to keep crops healthy and productive.¬†Creating an abundant supply of phosphorous is important for increasing food production to feed the world’s growing population.

Ostara is banking on worries — and debatable theory — that phosphorous reserves in mines are depleting, causing prices for this essential fertilizer ingredient to yo-yo dramatically in recent years. Major phosphorous producing countries include the U.S., China and Morocco.

Ostara's Hampton projectOstara’s process harvests the phosphorous and ammonia from the wastewater stream, which is diverted to its equipment, and then adds magnesium to cement a strong bond with the two minerals to form tiny crystals.

The crystals stay inside a reactor that grows the crystals until they reach about 1 millimeters to 2.5 millimeters in diameter. From there, a drying process gets rid of excess water in the crystals and also turns the crystals into a pure form that no longer contains human wastes and doesn’t smell bad.

Ostara then bags the crystals and sells them to fertilizer blenders who add other materials, such as potassium or nitrogen, to create fertilizers for sale. The startup’s technology could typically recover 25 percent to 30 percent of phosphorous in the sewage. The rest remains with the human wastes that needs treatment and disposal.

While processing phosphorous from sewage isn’t a new idea, what sets Ostara’s technology apart is its ability to grow the crystals to a large size and eliminate traces of organic materials, said Phillip Abrary, CEO of the Vancouver company.

Ostara process

In the less pure form, the harvested phosphorous wouldn’t meet the regulatory requirements for fertilizers in some parts of Europe and would have to be sold as waste byproducts, which fetch fewer dollars, Abrary added. The phosphorous in sewage comes from the fertilizers that grew the food we ate. In fact, 1 percent of the human body is made up of phosphorous, Abrary said.

Ostara not only sells and installs the phosphorous-recovering equipment, it also sells and ships phosphorous-based compounds. The company pays a previously negotiated price for phosphorous from the wastewater treatment plant. Ostara expects its system at Thames Water to produce 150 tons of phosphorous per year.

Taking phosphorous out not only generates revenues for the wastewater treatment plant owner, it also reduces the amount of chemicals the owner would use to de-clog the buildup of phosphorous and ammonia in the pipes. Using Ostara’s system could generate ¬£200,000 in savings per year for Thames Water, Abrary said.

The payback period for the project should last 10 years, though a larger system could cut that by half. Thames Water will decide whether to install more Ostara equipment at its other treatment plants after seeing how well the first project performs.

Ostara also has installed six other plants in the United States and Canada. The latest one is in Madison, Wisconsin, that is going through the commissioning phase and is eight times larger than the one at Thames Water, Abrary said. The company’s very first project, completed in 2009, was in Portland, Oregon.

All of its customers are utilities, though Ostara is working on equipment designed for industrial uses. The company, founded in 2005, has raised $35 million in venture capital so far from investors including Frog Capital, Vantage Point Capital Partners, Wheatsheaf Investments and Four Winds Capital.