Effect of salinity and temperature on the extraction of extracellular polymeric substances from an anaerobic sludge and fouling in submerged hollow fibre membranes

The results of the characterisation anaerobic sludge-derived extracellular polymeric substances (EPS) under different extraction conditions and their effects on fouling in submerged hollow fibre membranes are presented. A wide range EPS was obtained depending conditions. Proteins, polysaccharides, humic represented 80–99% total organic matter extracted, with 54–60% identified as substances. Ultrasonication more effective than vortex agitation, ensuring higher yields a shorter contact time. increase temperature from 30 °C to 50 decrease NaCl concentration favoured diffusion, but this positive effect negligible for an ultrasonic contact. Linear, quadratic, combined ultrasonication time solvent salinity were statistically significant ultrasonication-assisted extraction. highest yield achieved using at ºC least 60 min salt-free water solvent, extract 138.8 mg TOC/L obtained. Batch ultrafiltration-backwash tests permeation rates allowed determine specific resistance filtration extracts, which increased 103.8·10 12 m/kg TOC 169.4·10 presence 1.8 wt% NaCl. Salinity also provided rigidity gel layer, reducing compressibility index 0.23 0.03. • salt reduction diffusion EPS. Maximum required over water. Humic predominant side stream AnMBR sludge. Salt decreased layer compressibility. retention degree concentration.