Abstract: Extracellular polymeric substances (EPS) are the predominant
constituents of activated sludge and represent up to 80% of the mass of
activated sludge. They play a crucial role in the flocculation, settling and
dewatering of activated sludge. Furthermore, EPS also show great efficiency in
binding heavy metals. So EPS are key factors influencing reduction in sludge
volume and mass, as well as activity and utilization of sludge. EPS are of
considerable environmental interest and hundreds of articles on EPS have been
published abroad, while information on EPS in China is limited. In this paper,
results of over 60 publications related to constituents and characteristics of
EPS and their influences on flocculation, settling and dewatering of sludge are
compiled and analyzed. Metal-binding ability of EPS is also discussed, together
with a brief consideration of possible research interests in the future.