Advancement in the Use of Optical Properties for Water Quality and Water Reuse in Public Water Treatment Cycles

Abstract

Dissolved organic matter (DOM) is a complex mixture of organic compounds resulting from the breakdown and transformational products of higher forms of organic matter (i.e., plants, animals and microbes). DOM is also a ubiquitous constituent of natural and treated waters and known to play key roles in many environmental and engineered and treated systems. Examples include the global carbon flux, fate and transport of contaminants, light absorption and photochemistry in water, and the production of disinfection byproducts in water treatment systems. Analysis of molecular size and optical properties have emerged as useful techniques to characterize DOM in terms of source and chemical composition of DOM. These relationships are useful to the water treatment industry and allow DOM to be used as surrogates for the removal of contaminants and differentiate between water sources such as natural surface water and treated wastewater effluent. The main goal of my research is to advance the understanding of DOM molecular size and optical properties, their relationship to one another, and how they can be utilized in the water treatment industry, especially for potable water reuse treatment applications and the development of optical based sensors and probes. My research is primarily conducted using a size exclusion chromatography system (SEC) coupled with absorbance, fluorescence, and dissolved organic carbon (DOC) detection. In the Chapter 1, I develop a method to calculate fluorescence quantum yield as a function of molecular size and demonstrate the ability of this method to provide compositional information regarding absorbing and fluorescing fractions of DOM. In Chapter 2, I apply mass balance principals to blends of DOM sources to demonstrate conservative mixing behavior with respect to the molecular size distributions and optical properties of DOM. Finally, in Chapter 6, I investigate the composition of &ldquo;protein-like&rdquo; fluorescence components in DOM for a paired surface water and wastewater effluent to advance the understanding of these metrics in the context of an urban water cycle and inform future development of optical sensors.</p