Civil Engineering Departmental Seminar - Towards Phosphorus Sustainability with Circular Economy at the Water-Food-Energy-Carbon Nexus

Towards Phosphorus Sustainability with Circular Economy at the Water-Food-Energy-Carbon Nexus

Within the framework of the renowned phosphorus (P) paradox, P is an irreplaceable, scarce element for food security and renewable energy (biofuel) production and, at the same time, its inefficient use and loss to the environment is also the leading cause for widespread eutrophication that threatens global water security. To offer long-term off-site life cycle environmental and health benefits, there is an imperative need of paradigm shift towards a more sustainable regional-scale nutrient management system that incorporates P recycle from wastewater sources, water quality protection and,  energy and carbon demand abatement. Our team has been working on addressing the recognized three challenges that limit the implementation of sustainable P recycling and management system: 1) the need of an integrated  bioprocess for simultaneous energy capture, and nitrogen (N) and P remediation and recovery; 2) a lack of cost-effective  and environmentally-sound biotechnology for P recovery from high-strength agricultural wastes to enable P recycle; 3) unpredictable and largely unknown impact of recycled biofertilizer application on crop production and long-term soil health. Conventional biological nutrient removal (BNR) processes are usually energy intensive and require sufficient carbon, often additional external carbon, to reliably meet stringent regulatory requirements. Our research group are working towards breakthroughs in theoretical understanding and successful implementation of external carbon-independent, energy-efficient and reliable integrated A-stage carbon capture, side-stream enhanced biological phosphorus removal (S2EBPR) and short-cut N removal for simultaneous P, N and energy recovery from various municipal and agricultural wastewater. The S2EBPR technology creates a better controlled ecological selection condition that involves more favorable and different underlying mechanisms from those in convectional EBPR, thus overcome the challenges and limitations that prevent its coupling with carbon-capture and short-cut N removal processes. We integrated advanced genomics, phenotyping, data analytics and modeling to discover function-targeted and high-resolution ecological-system dynamics and rules. We pioneered the operational phenotypic units (OPUs) concept based on single cell Raman Micro-spectroscopy (SCRS), and developed phenotype-targeted genomics via coupled FACS-phenotyping-genotyping, which enabled a novel, non-invasive phenotyping method for revealing the microbial physiological diversities within ecosystems in response to stressors such as climate change. To close the circular economy for P sustainability, we aim to optimize the value-added product-biofertilizer from the above treatment process, which will alleviate the reliance on inorganic P fertilizers that has negative implications on soil health. In collaboration with the NSF CROPPs center team, we demonstrated the superiority of recycled biosolids on plant growth enhancement, and we are investigating the roles of key bioagents within the plant-rhizomicrobiome interactions in enhancing the plant health and resilience. These efforts contribute to the realization of the paradigm shift towards P sustainability with circular economy at the water-food-energy nexus.