WRF Launches Project to Demonstrate Phosphorus Recovery Using CalPrex System
DENVER, CO 11/30/18 – The Water Research Foundation (WRF) has launched a project, Demonstrating the CalPrex™ System for High Efficiency Phosphorus Recovery (5004), between the Milwaukee Metropolitan Sewerage District (Milwaukee, Wisconsin), Madison Metropolitan Sewerage District (Madison, Wisconsin), Metro Wastewater Reclamation District (Denver, Colorado), Massachusetts Water Resources Authority (Boston, Massachusetts), and Centrisys/CNP (Kenosha, Wisconsin), to demonstrate a high-rate, pre-digestion phosphorus removal and recovery technology. The technology, developed at the University of Wisconsin-Madison and licensed from Nutrient Recovery and Upcycling (NRU) by Centrisys/CNP under the name CalPrex™, ran as a ~10 gallon per minute pilot system from October through the end of November 2018 at the Madison Metropolitan Sewerage District. The demonstration has provided high-quality data that will allow utilities to evaluate high-rate phosphorus recovery and its effects on phosphorus load management.
The CalPrex™ phosphorus removal and recovery system incorporates a thickened sludge fermentation tank to increase the amount of soluble and reactive species of phosphorus, thereby increasing the recovery potential of that phosphorus. The system diverts over 50% of soluble phosphorus from the methane digester and, ultimately, from resulting biosolids. The CalPrex™ system recovers phosphorus in the form of brushite, a calcium phosphate mineral with high potential as a slow-release phosphorus fertilizer. The project will support and leverage efforts that NRU is undertaking in conjunction with a USDA SBIR grant and a supporting grant from the Center for Technology Commercialization in Wisconsin to establish brushite in the fertilizer market.