Influences of Extracellular Polymeric Substances (EPS) on Flocculation, Settling, and Dewatering of Activated Sludge

Results in over 200 publications related to constituents, quantities, and characteristics of extracellular polymeric substances (EPS) in activated sludge and their influences on sludge flocculation, settling, and dewatering are compiled and analyzed. Constituents and quantities of EPS are strongly dependent on the extraction process. Most results show that EPS in activated sludge comprise substantially more proteins than carbohydrates. EPS and sludge flocs carry negative zeta potentials and negative charge. Sludge hydrophobicity increases with protent content of the EPS, and an increased hydrophobicity generally leads to a better flocculation. Most data show that sludge settles less well, as measured by sludge…