Evolution of extracellular polymeric substances (EPS) in aerobic sludge granulation: Composition, adherence and viscoelastic properties.

In this study, we set up two reactors fed with COD/N ratios of 100: 5 (R1) and 100: 10 (R2) for comparison, to investigate the adhesive and viscoelastic properties of sludge EPS during the sludge granulation. We found that R2 showed a more rapid sludge granulation with more stable granules formed, contained a higher abundance of amoA gene, and had a higher production of polysaccharides than R1. We also found a sharp decrease in polysaccharide production and β-sheets abundance accompanied by granule size decrease in R1 on Day 80, indicating their essential roles in sludge granulation and granule stability. QCM-D (quartz crystal microbalance with dissipation monitoring) results showed that EPS became less adhesive and inclined to form unstable layers on the mineral surfaces along with the sludge granulation process. In contrast, they showed the opposite behavior and became more adhesive on the PVDF sensors. Our results suggested that higher polysaccharides, a higher β-sheets band in proteins, and lower mineral surface-adhesive and viscoelastic properties benefited the aerobic sludge granulation process and the granule maintenance.
PMID: 33182133 [PubMed - indexed for MEDLINE]

Source: Chemosphere - November 28, 2020 Category: Chemistry Authors: Shi Y, Liu Y Tags: Chemosphere Source Type: research