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Struvite Recovery

Nutrient Recovery
Ostara’s proprietary wastewater treatment technology, called the  Pearl® Nutrient  Recovery Process, recovers phosphorus and other nutrients from sludge liquids preventing the buildup of struvite scale in plant infrastructure and converting the recovered nutrients into a premium commercial fertilizer (Crystal Green®) (link to Crystal Green®).  

Wastewater treatment plants, particularly plants that practice biological nutrient removal and anaerobic sludge digestion, concentrate large quantities of nitrogen and phosphorus in their sludge handling streams.  These dissolved nutrients combine with magnesium to form struvite scale in piping, pumps and valves.  Plugging of the piping systems leads to pumping inefficiencies, reduced system capacity, high operating costs, maintenance shutdowns and pipeline failures. Struvite scale has an appearance and strength similar to concrete and must be removed either mechanically (using chisels or jackhammers) or by flushing with strong acids.  

Once integrated into the wastewater treatment system, the Ostara reactor initiates a chemical reaction that processes the sludge liquids and recovers phosphorus and other nutrients, dramatically reducing the phosphorus and ammonia load returned to the liquid treatment train by 90% and 20% respectively. The recovered nutrient stream is mixed with appropriate stoichiometric doses of magnesium chloride and caustic to precipitate struvite pellets.     

The pellets are then harvested from the reactor and formulated to become Crystal Green®, a high-quality environmentally friendly, slow-release, commercial fertilizer that provides revenue for the system’s operator.

Ostara’s Pearl® technology is based on a proprietary fluidized bed reactor that recovers ammonia and phosphate from nutrient rich fluids. The technology, created at the University of British Columbia, uses a proprietary fluidized bed reactor design which removes approximately 85% of the influent phosphorus, but also results in the formation of a fertilizer in granular form consistent with that used in the fertilizer industry.

The implementation of this technology at a wastewater treatment plant not only provides good fertilizer yields (P-Recovery > 85%), but also helps reduce effluent phosphate and ammonia levels, regardless of the wastewater treatment process employed. The technology development was also supported by the British Columbia provincial electricity utility BC Hydro, international engineering firm Stantec Inc., Vancouver-based NORAM Engineering and Constructors Ltd., and the Canadian federal government’s Natural Sciences and Engineering Research Council (NSERC), National Research Council (NRC) and Sustainable Development Technology Canada (SDTC).   

Ostara’s commercial-scale nutrient recovery systems have been operating since May 2007 as part of the City of Edmonton’s Gold Bar wastewater treatment plant and since May 2009 at the Durham Advanced Wastewater Treatment Facility in Tigard (Portland), Oregon operated by Clean Water Services.  Hampton Roads Sanitation District’s Nansemond Wastewater Treatment plant in Suffolk, Virginia will launch their Nutrient Recovery Facility using Ostara’s Pearl® process on May 27 2010 and the York Wastewater Treatment Plant will implement a commercial facility in York, Pennsylvania in summer 2010.

The technology has been and is currently being tested at pilot scale at several wastewater treatment facilities throughout North America and Europe.