Bioflocculants from wastewater: Insights into adsorption affinity, flocculation mechanisms and mixed particle flocculation based on biopolymer size-fractionation

Microbial extracellular polymeric substances (EPS) produced from wastewater are generally heterodispersed, which is expected to influence their flocculation performances and mechanism, particularly in mixed particle systems. The different molecular weight (MW) fractions should contribute the overall adsorption affinity mechanism of EPS single dual clay harvested bioreactors were size-fractionated into high, medium low MW (HMW, MMW, LMW, respectively). its characterised by diverse analytical techniques coupled with optical reflectometry investigate role each fraction kaolinite montmorillonite In systems, both HMW-EPS showed comparable performances. However, proved be more efficient than for flocculation. Site blocking effects observed EPS: LMW MMW first adsorbed surface due higher diffusivities faster mass transfer interface, while slowly transported but attached irreversibly stronger LMW/MMW-EPS. We propose this, a mechanism: extended anionic polymer tails solution, thereby enhancing