A pilot project at Clean Water Service's Durham Advanced Wastewater Treatment Facility in Tigard, Ore., is one of two sites in the U.S. demonstrating a new technology that removes phosphorus and other nutrients from wastewater and recycles them into environmentally safe commercial fertilizer.
The technology was developed by Ostara Nutrient Recovery Technologies Inc. of Vancouver to help wastewater treatment plants solve environmental problems, increase plant capacity and reduce maintenance costs, while also creating a revenue-producing byproduct.
Mark Poling, wastewater department director at Clean Water Services, said the Ostara pilot facility began operating in May 2007 in Tigard. Clean Water Services is monitoring the Ostara pilot plant results and will consider whether to build a full-scale plant using the new technology.
"The Ostara technology has the potential to provide some attractive operating efficiencies and capacity increases to the plant, as well as some important environmental benefits. We are closely monitoring the pilot plant operation to determine whether a full-scale commercial facility would be an appropriate addition to our Durham Advanced Wastewater Treatment Facility," said Poling.
Phillip Abrary, president and CEO of Ostara, said many wastewater treatment plants are effective at removing phosphorus and other pollutants and diverting them into a sludge stream of liquids and solids, but are left with the problem of handling this sludge.
Treatment systems typically separate sludge solids from liquids. Treated solids can be recycled as soil amendments, as the Durham facility does. Liquids are typically reprocessed back through the wastewater system, which adds costs to the system by clogging pipes with a concrete-like scale called struvite, the result of phosphorus and ammonia (nitrogen) combining with magnesium, and by consuming up to 25 per cent of the system's capacity.
"Our technology integrates into the treatment system, processes the sludge liquids and recovers phosphorus and other nutrients, and then converts them into a high-quality environmentally friendly commercial fertilizer that can generate revenue for the local utility," said Abrary.
"Our pilot plant at Durham has been able to consistently recover more than 90 percent of the phosphorus and 20 percent of the ammonia that would normally be recycled back to the plant from the solids processing."
Abrary said the first commercial scale plant using his company's technology was commissioned last month in Edmonton, Alberta, Canada. As many as 400 municipalities in North America and 500 in Europe are potential customers for the Ostara process.
The fertilizer byproduct from the Ostara process, named Crystal Green, is the only slow-release fertilizer with a combination of nitrogen, phosphorus and magnesium. A commercial-sized Ostara reactor would produce as much as 1,000 pounds of Crystal Green per day. The product is dried and bagged on site and is immediately ready for commercial sale.