Update on Ostara from the Centre European d’Etudes des Polyphosphates
SCOPE Newsletter – n° 70
OSTARA STRUVITE RECOVERY PROJECTS
North America’s first full-scale commercial struvite recovery reactor started operation in Edmonton, Canada, in early 2007 (see SCOPE Newsletter 65). Built by Ostara Nutrient Recovery Technologies Inc., the plant is based on the fluidised bed reactor technology developed by UBC (University of British Columbia) over recent years. The struvite fertiliser produced is marketed under the name of Crystal Green. A pilot plant is was tested at the Clean Water Services Durham Advanced Wastewater Treatment Facility, Oregon and successful tests have also been completed B at the Hampton Roads Sanitation District’s Nansemond Wastewater Treatment Plant, Suffolk, Virginia (Chesapeake Bay).
The Durham Plant discharges into the slow moving Tualatin River and applies strict phosphorus removal limits of 0.1 mg/L in the treated effluent. Sludge fermentation provides an organic substrate to feed biological nutrient removal. However, at present, 30% of sewage works inflow phosphorus and ammonia comes from the sludge dewatering return liquors. Struvite precipitation for P-recovery can remove this return phosphorus flow, thus improving biological nutrient removal performance.
The 8 week pilot trial of the Ostara reactor, treating around 1/300th of plant capacity A, demonstrated expected full scale performance and to enabled footprint and cost effectiveness of a full scale plant to be calculated.
Ostara indicate that the sale of the recovered struvite, as fertiliser, covers plant operating costs once installed. Capital costs are indicated at 1 – 3 million €, recoverable in 3-5 years through savings on sewage works operating costs.
Furthermore, each tonne of struvite fertiliser produced brings 4-6 tonnes of greenhouse gas credits.
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