Less attention devoting to the disposal of sewage sludge in China in the past decades led to unproper treatment of huge quantity of sewage sludge

which caused serious environmental problems. Since tremendous distribution of the enriched heavy metals in sewage sludge restricted its final land disposal

thus how those heavy metals are adsorbed onto the sludge has been highly concerned. Extracellular polymeric substances (EPS)

mainly composed of protein

humic acid

polysaccharides

etc.

is the main components of sludge organics. EPS traditionally exhibites a porous polymeric structure

and those polarity heavy metals can be easily adsorbed onto the adsorption sites (such as carboxyl and hydroxyl groups) which existes on the surface of EPS. Overall

the physicochemical structural characteristics of EPS significantly affects the adsorbing processes of heavy metals. In this study

we firstly gave a brief introduction to the current status of sludge treatment and disposal in China. Then

effect of the compositions and structures of sludge EPS on heavy metals adsorption was analyzed and the potential adsorption sites were summarized. Moreover

the analyzing approaches for studying the heavy metals adsorption processes were comparably evaluated. Finally

suggestions on the future research was raised pertinently.