Review on biosorption of heavy metals by activated sludge

The occurrence of heavy metals in our water resources is of continued concern for the health and safety of consuming public. The existing conventional water treatment plants may only partially remove heavy metals, a large fraction of the metals are released to the aquatic environment. Recently, activated sludge emerged as an eco-friendly bioadsorbent, is effective and low cost material option on the removal of hevy metals. This paper discusses the various parameters effected biosorption of heavy metals, such as temperature, pH, biomass concentration, concentrations of initial metal and other factors, etc.. In particular, the removal mechanism is emphasized because of its importance in understanding the reaction between the microorganisms and the metals.