APPLICATION OF BIOFILMS IN REMOVAL OF HEAVY METALS FROM WASTEWATER IN STATIC CONDITION

Abstract

This research utilized biofilms as a model in ecotoxicology to remove selected heavy metals (Cd, Cu, Cr, Zn and Pb) from wastewater in a static condition. Biofilms were grown in three graded concentrations of the metal leachates (0.625, 0.417 and 0.250 %), harvested after 1, 2 and 3 weeks and analyzed for heavy metals. Mean accumulations peaked on Day 21, and of Cd ranged from 0.000 to 0.040 (mean=0.00837±0.002), Cu from 0.000 to 0.212 (mean=0.03929±0.012), Cr from 0.000 to 0.500 (mean=0.05821±0.021), Zn from 0.000 to 1.456 (mean=0.31833±0.109) and Pb from 0.000 to 0.099 (mean=0.02129±0.006) mg/g in resultant biofilm formations. Accumulation of the metals increased significantly with time [F (205.59) >Fcrit (3.95) ] at the 95% confidence interval. Those of Pb was significantly higher in the 0.625% leachate mixture than control (Sig F=0.034) at P<0.05, even as those of Cd and Cu were slightly higher in the concentrations than control. Biofilm model removed small amounts of metals from wastewater stream in static condition.