MICROBIAL BIOSORPTION OF RADIONUCLIDES IN LIQUID EFFLUENT TREATMENT

There is no doubt that biosorption processes offer a promising and potentially highly efficient technology for removing radionuclides from liquid effluents. Several biosorption systems so far studied largely comply with the criteria for a competitive and successful alternative to conventional techniques (Section 1). Limitations in biosorption processes such as uptake inhibition by other waste-stream components, sensitivity to pH, nonselectivity and so on, are undoubtedly problematic but may be shared by conventional procedures. However, it may be possible to maniplulate biosorbents by a variety of techniques to achieve the most favorable and economic biosorption process and overcome some of the process difficulties. The use of relatively cheap waste-biomass from other industrial processes e.g., fermentations, polymer production, activated sludge, would improve the cost effectiveness of the biosorption process. Since there are mechanistic differences in radionuclide uptake with biomass type careful selection of biomass may help to accomplish maximum biosorption efficiency. If biomass is specifically grown for biosorption processes, careful control of growth condition is essential to ensure good biosorption process characteristics. However, it may be possible to modulate uptake by other procedures. Pretreatment of biomass by agents such as alcohol, KOH, and boiling can improve radionuclide biosorption capacity by large amounts (22,25,26). These pretreatments work through their denaturation or solvent effects exposing cell wall binding sites. © 1990 Humana Press Inc.