CONSIDERATIONS FOR APPLICATION OF BIOSORPTION TECHNOLOGY TO REMEDIATEMETAL-CONTAMINATED INDUSTRIAL EFFLUENTS

Inorganic contaminants present in waste streams may be removed by one of three methods, viz. physical, chemical or biological. Chemical and physical techniques have traditionally been employed to remediate such streams. However, due to the crisis of rapidly deteriorating potable water quality, legislation governing the levels of contaminants is bec oming progressively stricter. Therefore, alternative methods for treat ment have been investigated. Biosorption technology, utilising any nat ural form of biomass to passively adsorb and immobilise solubilised he avy metals or radionuclides, offers such an alternative. However, the technology needs to effectively complete both on a cost and performanc e basis with existing methods before industry will accept and implemen t it. A pilot-plant feasibility study, using waste activated sludge to bioremediate a metal plating effluent, showed that the currently used method of chemical precipitation is more cost-effective. This paper d escribes the factors that must be considered when selecting bioremedia tion as a cleanup technology for inorganics.