A QSAR model for desorption of halogenated aliphatics from biosolids

Data collected from different wastewater treatment processes have provided statistically significant evidence that many toxic organic contaminants concentrate to several orders of magnitude greater than influent concentrations in industrial and municipal wastewater sludges. Because of the reversibility of sorption processes, it is possible for sorbed organic compounds to desorb at a later time, hence making disposal of these sludges a potential problem. Although a number of models have been developed to predict sorption parameters, they have all been based on empirically derived descriptors, the validity of which is seriously compromised by the variation in available data for these parameters. In this study, a reliable QSAR model based on theoretically derived molecular connectivity indexes has been developed to predict the release of halogenated aliphatic hydrocarbon compounds from activated sludge solids. Model development was conducted using a statistically designed training set of compounds.