New Process Makes Asset of Phosphorus and Nitrogen from Wastewater
Hazen and Sawyer Installs Ostara’s Pearl Process at Nansemond Treatment Plant
(HAMPTON ROADS, VA – June 4, 2010) – Hazen and Sawyer has recently provided engineering and construction administration services for a Struvite Recovery Facility at the 30-mgd Nansemond Treatment Plant (NTP), owned and operated by Hampton Roads Sanitation District (HRSD). The facility utilizes Ostara Nutrient Recovery Technologies Inc. (Ostara’s) Pearl® Process to produce a fertilizer used by golf courses, plant nursery operations, and specialty agricultural markets.
The new facility is the largest of its kind in operation and only the second operating in the United States. The design and construction of the facilities was fast-tracked to have the fertilizer ready for the Spring 2010 market. The project was a quasi design/build project with the Ostara equipment being procured under the Public-Private Educational Infrastructure Act (PPEA) with Hazen and Sawyer coordinating the design with the manufacturer and the Contractor.
The NTP discharges to the James River, a tributary of the Chesapeake Bay. To reduce nutrient loads to the Chesapeake Bay, HRSD established that the NTP would need to meet or exceed an annual average effluent TN of 8 mg/L and TP of 1 mg/L. Ostara’s process is expected to remove 90% of the phosphorous as well as 10% of the ammonia in the centrate. This will result in a 25-30% reduction of the phosphorous load to the biological nutrient removal basins. This process is designed to beneficially recover phosphorus and nitrogen from wastewater side-streams in a centrate treatment process aimed at creating a revenue-producing byproduct, an environmentally-friendly, slow-release fertilizer, called Crystal Green®.
Ostara’s process consists of patented fluidized bed reactors that recover ammonia and phosphorus from the waste recycle streams (commonly centrate stream). The nutrient rich recycle stream is mixed with appropriate stoichiometric doses of magnesium chloride and caustic to precipitate struvite pellets. The pellets are then harvested from the reactors, dried and bagged for sale.
Prior to implementing this technology, Hazen and Sawyer evaluated the technology against more traditional side stream treatment applications, such as phosphorus removal by ferric chloride addition, and demonstrated that Ostara’s Pearl® Process is a cost effective solution at the NTP.
Since our founding in 1951, Hazen and Sawyer has focused on two things: providing safe drinking water and controlling water pollution. Our range of services encompasses the planning, design, and construction management of water and wastewater-related projects – from clean water treatment, storage, and distribution to wastewater and stormwater collection, treatment, and reuse.