REMOVAL OF HEAVY-METALS FROM EFFLUENT STREAMS - WHY SELECT A BIOLOGICAL PROCESS

The paper addresses the use of biosorptive, bioaccumulative and other separative technologies for the removal/recovery of metals from liquid effluents. The reasons for selecting more conventional chemical treatments are reviewed whilst the advantages of a biosorptive process compared with a bioaccumulative one are described. Comparative costs for biosorptive processes with ion exchange and chemical precipitation using either lime or caustic soda are predicted. It is proposed that these costs, although indicative, are sufficiently accurate to justify further evaluation of bioprocesses. More definitive costs will be achieved by the use of multidisciplinary groups, and will ensure the true potential for metal biosorption/bioaccumulation is achieved.