Date of Award

Spring 1996

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering - (Ph.D.)

Department

Civil and Environmental Engineering

First Advisor

Hsin Neng Hsieh

Second Advisor

Su Ling Cheng

Third Advisor

Robert Dresnack

Fourth Advisor

S. Mitra

Fifth Advisor

Dorairaja Raghu

Abstract

Data collected from different wastewater treatment processes have provided statistically significant evidence that many toxic organic contaminants on EPA's list of priority pollutants concentrate 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 whose validity is seriously compromised by the variation in available data for these parameters. In this research 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. Sorption of halogenated aliphatics was observed to be a totally reversible process, which was modeled by a QSAR model based on the first order molecular connectivity index for activated sludge solids fractionated at a Relative Centrifugal Force (RCF) of 5000 x g.

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