Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Environmental Engineering (MS)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Daisuke Minakata

Committee Member 1

Paul Doskey

Committee Member 2

Sarah Green


With more than half of the nation’s drinking water affected by wastewater discharge from upstream and more indirect and direct reuse of treated wastewater, human health and ecotoxicological impacts resulting from effluent organic material (EfOM) will increase. Dissolved free amino acids (DFAAs), nitrogen components of EfOM, are essential nitrogen sources for microorganisms and play important roles in global N-cycling in natural aquatic environments. Several DFAAs including histidine, methionine, and tyrosine in sunlit surface waters are susceptible to direct and indirect photochemical transformation with reactive oxygen species. In this study, we investigated the reaction kinetics and initial reaction mechanisms involved in the fate of DFAAs through temperature-dependent bench-top photolysis experiments. Three prevalent surrogate DOM compounds were chosen (1,4-naphthoquinone, umbelliferone, 2-naphthaldehyde) which have been shown to be critical photosensitizers in the natural environment leading to the production of photochemically-produced reactive intermediates (PPRI) such as singlet oxygen (1O¬2), excited triplet state CDOM (3CDOM*), and hydroxyl radicals (HO•). All chosen surrogate DOM compounds and amino acids are structurally unique generating distinct degradation pathways of amino acids at three different temperatures (10 °C, 20 °C, 30 °C).