Nutrients from Wastewater: Rethinking Contaminants as Resources to Recover

Water contamination is ubiquitous and persists across our water resources and supply. Much attention is given to newly identified and emerging contaminants, but we also struggle to successfully mitigate “old,” or well-known, contaminants, which have included ammonia, nitrate, and, more recently, phosphate in municipal wastewaters. However, these compounds are also critical nutrients used to support the global industrialized agriculture sector. Phosphate is of particular importance and concern because phosphate-based fertilizers are currently produced through the mining of phosphate rock, a limited resource mineral. The world’s known available supply of phosphate rock is currently predicted to become limited within the range of 30–200 years, and the flow of phosphorus through the agricultural food cycle is unidirectional, with large portions of mined phosphorus ending up in wastewaters and landfills. Meanwhile, the technical treatment train for municipal wastewater treatment facilities targets removal of ammonia and phosphate as contaminants, enabling this one-way flow of phosphorus from mineral source through food to waste. This Scenario is no longer tenable as we face limited phosphorus worldwide, and alternative approaches that enable phosphorus recycling and reuse are required. In our research, we are generally interested in understanding how an improved understanding of materials chemistry in aqueous systems can help to better engineer treatment solutions, as well as think about alternatives to traditional treatment approaches. In this talk, I will discuss our current research project focused on phosphate recovery from wastewaters through electrochemistry within the overall Idea of changing municipal wastewater treatment from primarily contaminant removal to include resource recovery. This project includes an interdisciplinary team of six research groups across electrochemistry, electrochemical engineering, agronomy, agricultural economics, life cycle analysis, and protein engineering. My talk will discuss our Interdisciplinary approach to phosphate and ammonia recycling from wastewater and will include initial results from our first year of working together, including results on electrochemical recovery of struvite (magnesium ammonium phosphate), design and scale-up of struvite production, soil and row crop studies on recycled versus commercial fertilizer products, protein engineering to facilitate struvite precipitation kinetics, and initial life cycle analysis and technoeconomic models that include struvite recovery as a phosphate recycling approach.