Struvite is a phosphate mineral crystal that forms inside pipes in wastewater treatment plants and is a major nuisance. The Metro Wastewater Reclamation District is proactive in executing phosphorus-removal technology on a large scale. Metro is the largest wastewater district in Colorado, and the PAR 1280 installation we built for the district at the Robert W. Hite water treatment facility in Denver is the world’s largest struvite reactor. The facility’s new phosphorus recovery facility removes phosphorus struvite after the solid’s digestion stage of the process and prior to the dewatering stage.

The 74-foot-tall struvite reactor tank holds 377,000 gallons of digested sludge material that moves constantly through the reactor.  The Metro District treats 130 million gallons of wastewater per day. When the delivery schedule of the reactor tank was delayed, we re-sequenced the project schedule to account for the delayed arrival. Resequencing of the Reactor Tank installation in turn required the project team to build the steel tank beside the facility and move it into place in two pieces by crane. We put together a detailed rigging plan to identify and prevent any potential hazards in lifting these loads, which exceeded 130,000 pounds.

With the new reactor in place, less struvite will form inside piping at the water treatment plant, and the environment will benefit because the facility will release less phosphorus back into water ways.  Though phosphates are a nuisance for water treatment, the struvite story is not all bad: once removed from wastewater, struvite has a market value as a slow-release fertilizer.

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