Title
Electrocoagulation-Electrooxidation for Mitigating Trace Organic Compounds in Model Source Waters
Date of Award
Spring 2019
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Civil Engineering
First Advisor
Mayer, Brooke K.
Second Advisor
McNamara, Patrick J.
Third Advisor
Young, Kyana RL
Abstract
Conventional coagulation and oxidation are well suited for many drinking water operations to meet regulatory requirements for safe drinking water. However, these processes require auxiliary chemicals and materials that must be transported from off-site, which increases complexity of operations, and can pose difficulties for small treatment systems. Electrochemistry offers an innovative method to induce coagulation and oxidation processes for water treatment. Electrocoagulation (EC) together with electrooxidation (EO) is an attractive option for drinking water treatment systems because these processes generate iron coagulants using iron EC electrodes and oxidants (e.g., free chlorine and reactive oxygen species) using boron-doped diamond EO electrodes. This research evaluated the performance of combined EC-EO as a water treatment process for mitigating trace organic compounds in model groundwaters and surface waters. The trace organic compounds evaluated were acyclovir, trimethoprim, and benzyldimethyldecylammonium chloride (BAC-C10). These compounds represent different classes of trace organics found in source waters for drinking water treatment facilities. EO-only removed greater than 70% of acyclovir and trimethoprim in model groundwater matrices, but negligible BAC-C10 was removed relative to control experiments. Alternately, in surface waters, EO-only treatment was effective for BAC-C10 removal, but not for acyclovir and trimethoprim removal. EC-EO for model surface water treatment removed 73.5 ± 1.25% of dissolved organic carbon and improved downstream EO treatment of acyclovir, trimethoprim, and BAC-C10 by factors of 3.4, 1.7, and 1.4, respectively based on mean removal. However, EC-EO of model groundwater improved removal for only BAC-C10 (factor of 5.2 improvement), whereas ACY and TMP removal did not improve. BAC-C10 removal via EC-EO in groundwater was attributed to the particle separation step. EO was generally more energy efficient in treating model groundwaters than model surface waters. EC-EO improved the energy demands for treating model river water.