Anaerobic Granulation: Interplay between Substrates, Microbial Communities, and Viscoelastic Properties of their Exopolymers

Samenvatting (Engelstalig)

Four lab-scale upflow anaerobic sludge blanket reactors fed with (a) glucose (RGlu), (b) acetate and tryptone (RAc+Try), (c) glucose and tryptone (RGlu+Try), and (d) glucose and starch (RGlu+Sta) were operated to investigate the role of proteinaceous substrates and substrate energy in biomass retention and anaerobic granulation from dispersed sludge. Microbial communities involved in the granulation process were further analyzed using 16S rRNA sequencing. Later, the response of extracellular polymeric substances (EPS) viscoelastic properties and granules physical characteristics to varied sludge loading rates (SLRs) were examined with the granules formed in RAc+Try, RGlu+Try, and RGlu+Sta. To explore more general relationships between granule strength and various EPS viscoelastic properties, anaerobic granules from nine full-scale wastewater treatment plants treating diverse wastewaters were characterized. Lastly, the viscoelastic properties of EPS extracted from these granules using various methods (e.g., alkaline heating and ultrasonication followed by cation exchange resin) were compared to provide insights for future applications.