Struvite had become a serious problem for the Tres Rios Water Reclamation Facility in Arizona’s Pima County.
The buildup of struvite occurred downstream of the anaerobic digesters and especially in the centrifuge facility where biosolids are dewatered from 2.5% to 18-20% solids. “We’d see it form especially in the centrate lines because the centrate was so phosphorus-laden,” says Steven Richey, plant manager.“Struvite is kind of like kidney stones. It’s made up of the same material. With the amount of phosphorus we had in the system, we were almost totally occluding pipes. It was almost like the formation of concrete on the
