In the fall of 2018, the Water Research Foundation (WRF) launched a project to demonstrate the capabilities of CalPrex, a high-rate, pre-digestion phosphorus removal and recovery technology. The project is being conducted in participation with Nine Springs Treatment Plant (Madison, WI), Milwaukee Metropolitan Sewerage District (Milwaukee, WI), Metro Wastewater Reclamation District (Denver, CO) and Massachusetts Water Resources Authority (Boston, MA). Additional participants include Colorado School of Mines (Golden, CO), University of Wisconsin-Madison (Madison, WI), Black and Veatch (Madison, WI), Hazen and Sawyer (Virginia Beach, VA), Centrisys/CNP (Kenosha, WI) and Upcycling (Madison, WI).
The CalPrex technology, licensed from Nutrient Recovery and Upcycling (NRU) by Centrisys/CNP, ran as a 10 gallon per minute pilot system from October through the end of November at Madison’s Metropolitan Sewerage District’s Nine Springs Treatment Plant. As part of the WRF project, the CalPrex system incorporates a thickened sludge fermentation tank or acid digester to increase the amount of soluble phosphorous, thereby increasing the recovery potential of the phosphorus.