Link phylogenetic and phenotypic characteristics to reveal factors governing enhanced biological phosphorus removal (EBPR) process performance and stability

• Online Access: http://hdl.handle.net/2047/D20250824

In defense of the continuously impaired water quality, U.S. EPA regulations are now implementing increasingly stringent wastewater phosphorus (P) controls to more areas, resulting in great challenges for current P removal technologies. The enhanced biological phosphorus removal (EBPR) process is recognized as a promising alternative strategy to achieve sustainable P removal and recovery with minimized economic and environmental costs. However, a number of knowledge gaps and technical barriers still exist that hamper the wide application and full realization of the advantages of EBPR. They include insufficient understanding of the EBPR phylogenetic and metabolic/functional ecology and mechanisms involved in biological P removal activity, and consequently a lack of mechanism-based design, model and optimization guidance to ensure performance reliability and to fully realize its potential and advantages. This poses a pressing need for the development of new tools to elucidate not only the phylogenetic/taxonomic diversity, but maybe more importantly, the metabolic/functional characterizations among EBPR microbial populations and their linkage with EBPR performance and long-term stability. In this study, we developed, refined and validated novel, powerful advanced molecular and spectromicroscopy tools, including single-cell Raman-fingerprinting, Raman- fluorescence in situ hybridization, scanning electron microscopy and energy disperse X-ray microanalysis , as well as 31P-nuclear magnetic resonance and polyacrylamide gel electrophoresis techniques, for single-cell level metabolic/functional characterization of EBPR microbial community. Then, we employed combination of these new techniques and the state-of-art, high throughput next generation sequencing techniques, to elucidate the mechanism and factors that govern the EBPR stability for achieving extremely low limits levels. We also pioneered the characterization of intracellular polyphosphate structure dynamics, and its association with long-term EBPR stability. Through simultaneous phylogenetic and phenotypic/metabolic characterization, we, for the first time, revealed the associations and correlations among EBPR phylogenetic diversity, metabolic/functional diversity in terms of cellular inclusion and structural profiles, glycolysis pathway involvement, polyphosphate structure and elemental composition characterization and the consequent EBPR stability. This led to new knowledge and insights in our fundamental understanding of EBPR process, which would improve our ability to design and implement more effective and reliable EBPR as an alternative and sustainable strategy for P removal and recovery.