Ultraviolet advanced oxidation processes were compared using sodium perborate (UV/NaBO3 AOP) or hydrogen peroxide (UV/H2O2 AOP) for 1,4-dioxane removal from tertiary wastewater effluent. Both UV/H2O2 and UV/NaBO3 AOPs were also tested with the addition of acetic acid. Results revealed that sodium perborate performed similarly to hydrogen peroxide – the UV/NaBO3 AOP with 6 milligrams per liter (mg/L) as H2O2 resulted in 43.9 percent 1,4-dioxane removal, while an equivalent UV/H2O2 AOP showed 42.8 percent removal. Although the oxidants performed similarly, NaBO3 is an average of 3.3 times more expensive than H2O2. However, the solid form of NaBO3 can provide a major benefit to remote and mobile operations. Unlike H2O2 solution, which degrades over time and requires repeated costly shipments, NaBO3 is a convenient source of H2O2, and a long-term supply can be shipped at once and mixed into solution as needed. Additionally, acetic acid addition increased 1,4-dioxane removal by 5.7 percent in an UV/H2O2 AOP. It is proposed that the UV irradiation of acetic acid produced the acetoxyl radical, which cohesively works with the hydroxyl radical, produced via H2O2 irradiation, to enhance 1,4-dioxane degradation in a combined, novel UV/H2O2/acetic acid AOP. Other UV-AOP observations relate to a decrease of up to 29 percent in total dissolved solids (TDS), an inverse relationship between TDS and turbidity removals, and degradation of organic matter. Despite organic matter changes, the UV/NaBO3 AOP did not reduce trihalomethane formation due to the increased chlorine demand from hydrogen peroxide residual. Additionally, new insights into limitations of H2O2 residual test methods are included.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2658 |
| Date | 01 January 2023 |
| Creators | Shukla, Tulsi |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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