| This dissertation presents three studies related to removal of emerging contaminants (ECs) from water. The first study summarized literature on ECs including classification, sources, effects of exposure, and treatment techniques for removal of ECs. The second and the third studies focused on the fate of three ECs (3-tert-Butyl-4-hydroxyanisole (BHA), chlorpyrifos, 1,3,4,6,7,8- hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyrane (HHCB)) by simulating conditions of a conventional wastewater treatment plant (WWTP) in San Antonio, Texas on laboratory scale. The second study estimated partition coefficients of ECs, each individually and in combination, to activated sludge at 22°C. Results showed that the sorption isotherms followed a linear trend (r2≥0.9) when studied each EC individually generating sorption coefficients to sludge (Kd) values of 2689 L kg-1, 27786 L kg-1 and 31402 L kg-1 for BHA, chlorpyrifos and HHCB respectively. The combined study isotherm followed a linear trend and generated a Kd of 1766 L kg -1 which is 34% less when compared to individual study isotherm for BHA suggesting the presence of competing effects for sorption sites. The combined sorption study data for both HHCB and chlorpyrifos failed to follow linear isotherm trends and were analyzed using Freundlich's and Langmuir's isotherm models. Synergistic effects on the concentration of the ECs in the liquid phase as well as competition for sorption sites were observed with spike concentrations > 20 mg L-1 and > 25 mg L-1 for HHCB and chlorpyrifos respectively. The Kd values varied between 6,000,000-16,984 L kg -1 and 3,000,000--19,536 L kg-1 for HHCB and chlorpyrifos respectively. The third study concentrated on the degradation of the ECs in aerobic and anaerobic treatments with conditions emulated from the WWTP. The ECs mostly degraded in aerobic conditions that were acclimated with the ECs. Important phenomena such as sorption-desorption dynamics, interaction between ECs, response of microbial organisms and their complexities involved to degrade multiple ECs help to explain the data obtained for aerobic degradation study. Little or no degradation of ECs were observed when exposed to simulated anaerobic conditions. |
