Opportunities for using two low-cost methods for treatment of metal bearing aqueous streams

The feasibility of two non-traditional approaches—use of reedbeds as a natural wetland, and adsorption on lignite and its maceral fractions—for their potential application in effluent treatment is discussed. The main mechanisms encountered in wetlands performance are briefly described, together with their advantages and disadvantages in practical operation as well as the various methods for metals extraction from the wetland sediment. The preliminary results from a pilot scale wetland operation for metallurgical effluents purification are analysed. The results obtained from the second approach, i.e. using the coal refined fractions, have shown the superior performance of the denser fraction which resembles to a certain extent the activated carbons. Isotherms determination and electrophoretic measurements have confirmed the above findings.