Enhancement of Metal Sorption by Composted Paper Mill Waste Following Microbial Manipulation

The biosorptive-capacity of composted paper mill waste (PMW) for the heavy metals [Cd(II), Cu(II), Pb(II) and Zn(II)] was improved by inoculation of sterilized compost with a Bacillus brevis strain followed by incubation. This strain was originally isolated from the compost and adsorbed up to 31% of its dry weight of lead and 28% in copper at an initial concentration of 185.2mg/L and 182.3mg/L respectively. Estimated numbers of the bacterium following 21 days growth in the compost at 25°C reached 109 cells/g. The modified compost exhibited up to a three-fold increase in capacity for removal of lead and up to a two-fold increase in capacity for removal of copper from aqueous solution.