Date of Award
Master of Science (MS)
The application of ozone for the advanced treatment of wastewater effluents is currently being evaluated throughout the world. Application of ozone to wastewater results in disinfection and significant oxidation of emerging contaminants of concern, including pharmaceuticals and personal care products. The impact of wastewater derived effluent organic matter (EfOM) on the application of ozone for the oxidation of organic contaminants was evaluated for four wastewaters (sites A, B, C1 and C2). Specifically, the ozone decomposition and concurrent formation of hydroxyl radical (HO•) from EfOM as a function of apparent molecular weight (AMW). Each collected water was fractionated into four fractions (< 10 kDa, < 5 kDa, < 3 kDa, and < 1 kDa) and characterized in terms of chemical and physical properties. The RCT, defined as the ratio of HO• exposure to ozone exposure (∫HO•dt / ∫O3dt), was measured for all fractions and bulk waters, with an initial ozone dose equal to the total concentration of EfOM. The RCT of all the waters and pseudo first order decay rates of two of the waters increased significantly (95% confidence) from the bulk sample to the < 10 kDa fraction. The formation of HO• was modeled for the C1 and C2 waters and fractions. The model showed that < 3% of the HO• formation was attributed to the organic matter with AMW >10 kDa for the C1 water and < 18% of the HO• formation for the C2 water. This demonstrated that the organic matter with AMW > 10 kDa was relative unreactive towards ozone as well as being a relative insignificant source of HO•. Coagulation was investigated as a pretreatment step to increase the pharmaceutical removal efficiency of the wastewaters with ozone via jar tests. The coagulated water showed a dramatic increase in the ozone pseudo-first order decay rate as well as the RCT. Contaminant oxidation was also preformed on the C2 samples. The coagulated water showed greater contaminant removal than the bulk sample. The results help support the hypothesis that EfOM plays the dominant role in ozone decomposition throughout the reaction.
Gonzales, Sarah, "Impact of Effluent Organic Matter on the Application of Ozone for Treatment of Organic Contaminants from Wastewater" (2010). Civil Engineering Graduate Theses & Dissertations. 36.