INVESTIGATION OF SOLIDIFICATION FOR THE IMMOBILIZATION OF TRACE ORGANIC CONTAMINANTS

The purpose of this study was to determine the degree of organic contaminant immobilization obtainable using several generic solidification processes (cement, cement/fly ash, cement/activated carbon, cement/bentonite and cement/soluble silicates). This laboratory-scale study was designed to simulate a situation in which a largely inorganic residue containing trace amounts of organic contaminants is solidified. Twenty organic contaminants, representing eight categories of organic priority pollutants, were selected based on a hazard index which considered chronic toxicity, solubility and persistence in groundwater. The batches were spiked with a mixture of the organic contaminants at three concentration levels of each of the contaminants (10, 100 and 1000 μg/g of solidified waste). Mobility of the organic contaminants was assessed by calculating partition coefficients between the solid and the liquid phases from the results of a distilled water extraction. The results were analyzed based on the water solubility and volatility of contaminants, as well as the fixation capacity of the solidification processes.