Durham houses first full-scale commercial nutrient recovery facility in the nation
Clean Water Services Durham Advanced Wastewater Treatment Facility is the first facility in the United States to recover fertilizer from a natural byproduct of wastewater treatment. Using technology developed in Canada by Ostara, a $2.5 million struvite recovery system with three reactor vessels has been constructed. The system is expected to produce 500 tons of premium, slow-release fertilizer per year. This innovation will save energy and maintenance costs, increase capacity at the treatment facility and is expected to pay for itself in five years.
The challenge
To meet the tight discharge criteria on the Tualatin River, the Durham facility must seasonally treat phosphorus to a limit of 0.1 mg/l. One of the greatest challenges, common with biological phosphorus removal facilities, is that phosphorus and other nutrients from the sludge handling processes are recycled within the wastewater facility which adds to the operating costs and takes up plant capacity. Additionally, phosphorus, ammonia, and magnesium become highly concentrated in the sludge-handling process and cause the formation of struvite (magnesium ammonium phosphate). The struvite formation coats pipes, valves, and other equipment which reduces flow capacities and increases maintenance requirements.
Watch a video about the Ostara/Clean Water Services partnership.
Solution: A sustainable technology by Ostara
Ostara Nutrient Recovery Technologies Inc. has developed a technology to simplify the treatment process by directly removing phosphorus and ammonia from wastewater that would otherwise have to be retreated. This proprietary technology, called the PEARL™ process, diverts the phosphorus and other nutrients to a reactor that converts them into a premium, slow-release, environmentally friendly commercial fertilizer product called Crystal Green®.
Compared to conventional fertilizer manufacturing, the production of Crystal Green® is highly energy-efficient and far less polluting to the atmosphere. And unlike fertilizers mined or derived from hydrocarbon sources, Crystal Green® is a recycled and renewable product that is safe to use on plant material, which makes it ideal for golf courses, commercial nurseries and specialty agricultural markets.
Unique partnership: Nation’s first full-scale commercial phosphorus recovery facility
After a pilot project, Clean Water Services and Ostara Nutrient Recovery Technologies formed a partnership to construct a full-scale facility at the Durham facility to remove polluting nutrients and produce Crystal Green®. The facility began commercial operation in May 2009, making Durham the nation’s first full-scale commercial phosphorus recovery facility.The facility is owned and operated by Clean Water Services while Ostara will market Crystal Green® to nurseries throughout Oregon and the Pacific Northwest. This facility is projected to remove more than 90 percent of the phosphorus in the recycle stream and produce 40 tons of Crystal Green® fertilizer per month. The state-wide phosphate detergent ban reduced phosphorus load to the treatment plant by 22 percent, the Ostara system will reduce it an additional 24 percent. Clean Water Services will share revenue from the commercial sale of the fertilizer with Ostara, and it is expected that the initial investment in the technology will be paid back within five years.
Multiple benefits
In addition to phosphorus recovery, the PEARL™ process offers additional benefits to the Durham Advanced Wastewater Treatment Facility:
- Pollution reduction
- Reduced chemical use
- Revenue generation from the sale of the Crystal Green® fertilizer produced (Depending on the direct cost savings and the revenue generated by selling the product, the return of investment can be seen within five years)
- Increased wastewater treatment facility reliability and capacity
- Reduced operations and maintenance costs (OSTARA system prevents plant downtime and maintenance costs of cleaning clogged pipes, pumps and other equipment, and reduces sludge volumes and disposal costs)
- Reduced greenhouse gas emissions through reduced energy usage
- Potential generation of carbon credits
Lean more about Ostara.
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