Date of Award

2011

Degree Type

Thesis

Degree Name

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Dr. Ernest K. Yanful

Abstract

Over the past few years, pharmaceuticals and endocrine disrupting compounds have been identified as emerging environmental contaminants, and their presence and persistence in the aquatic ecosystem at low and yet discernible concentrations (ng/L - pg/L) have been highlighted. An understanding of the occurrence and behaviour of these compounds in wastewater and other water matrices is necessary for addressing the risks they pose to the aquatic environment. As the concern about these non-biodegradable recalcitrant compounds grows, their removal from water is becoming imperative. This urgent issue has led to an increasing number of studies on using or adapting various technologies for

treating water contaminated with these compounds.

The present study focused on the detection of the target analytes (ibuprofen and naproxen) at trace concentrations (ng/L - pg/L) in wastewater and surface water in and around southwestern Ontario. The study examined the removal of the target analytes from the various water matrices (laboratory grade water, wastewater effluent, and surface water) under spiked conditions. The work involved kinetic studies designed to determine fluence based and time based rate constants. Liquid-liquid extraction followed by GC/MS, using positive electron ionization mode, was used to analyze and to quantify the target analytes. A bench-scale study of their degradation was carried out in diverse water matrices using UV alone and UV/H2O2 based advanced oxidation process that employed low pressure (LP) and medium pressure (MP) lamps.

The observed concentrations of the target compounds in wastewater influent ranged from zero (or below detection) to 17 pg/L, compared to the method detection limits of 0.01 pg/L to 0.045 pg/L. The study found that during LP-UV treatment, the degradation of ibuprofen by direct photolysis was 35%-52% of its initial concentration in the three water matrices, whereas naproxen concentration was reduced by approximately 73%-79%. On the other hand, when MP-UV treatment was used, ibuprofen concentration was reduced by 79%-82% and naproxen to levels 91%-99%. Both target compounds degraded to concentrations below method detection limits following the use of MP-UV in addition to 20 mg/L of hydrogen peroxide. The findings of the study suggest that ibuprofen and naproxen are present in the London, ON wastewater treatment plant influent. The results further showed that UV/H2O2 based oxidation process is a promising technology for the removal of ibuprofen and naproxen present in a range of water from spiked laboratory grade water to sewage treatment effluent

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