Density-Based Separation of Microbial Functional Groups in Activated Sludge

Lin Li, Yaqi You and Krishna Pagilla
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Lin Li: Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA
Yaqi You: Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA
Krishna Pagilla: Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA

IJERPH, 2020, vol. 17, issue 1, 1-16

Abstract: Mechanistic understanding of how activated sludge (AS) solids density influences wastewater treatment processing is limited. Because microbial groups often generate and store intracellular inclusions during certain metabolic processes, it is hypothesized that some microorganisms, like polyphosphate-accumulating organisms (PAOs), would have higher biomass densities. The present study developed a density-based separation approach and applied it to suspended growth AS in two full-scale domestic water resource recovery facilities (WRRFs). Incorporating quantitative real-time PCR (qPCR) and fluorescence in situ hybridization (FISH) analyses, the research demonstrated the effectiveness of density-based separation in enriching key microbial functional groups, including ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and PAOs, by up to 90-fold in target biomass fractions. It was observed that WRRF process functionalities have significant influence on density-based enrichment, such that maximum enrichments were achieved in the sludge fraction denser than 1.036 g/cm 3 for the enhanced biological phosphorus removal (EBPR) facility and in the sludge fraction lighter than 1.030 g/cm 3 for the non-EBPR facility. Our results provide important information on the relationship between biomass density and enrichment of microbial functional groups in AS, contributing to future designs of enhanced biological treatment processes for improved AS settleability and performance.

Keywords: activated sludge; density-based separation; enrichment of microbial functional groups; ammonia-oxidizing bacteria (AOB); nitrite-oxidizing bacterial (NOB); phosphate accumulating organisms (PAOs); qPCR; FISH (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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