Modeling Advanced Oxidation Processes for Water Treatment

Abstract

Civilization is dependent on wastewater treatment plants. However, many conventional wastewater treatment processes only partially remove trace organics that result from human use, such as pharmaceuticals and endocrine disrupters. Advanced oxidation process (AOP) can be used to remove chemicals that may remain in the treated wastewater. AOP is an enhanced alternative to the traditional water treatment processes because it turns water contaminants into carbon dioxide (CO2), as opposed to simply transporting the contaminants across the different treatment phases. In order to model this process, one proposed idea uses ultraviolet light and hydrogen peroxide to oxidize the unwanted organic compounds. Previous mathematical models have been developed to simulate the UV/H2O2 process, however, the model employed in this work has advanced beyond previous efforts. Our UV/H2O2 model aims to characterize the mechanism and kinetics behind the decomposition of nonylphenol (NP) and p-cresol (PC), two chemicals in wastewater that serve as surrogates for endocrine disrupters. The model demonstrates agreement between experimental results and AOP simulations accounting for light intensity, pH, hydrogen peroxide levels, and concentrations of other radical scavengers. Our goal is to improve an already robust UV/H2O2 AOP model by taking into account spatial variations of radical concentrations. Our results take into account time and space, and show significant improvement in the accuracy of the model. This broadens the applications of this model and consequently, the degradation of organic contaminants is predictable over a wide range of conditions. The potential for polishing conventionally treated wastewater is evident.