Fluorescence as a Surrogate Measurement of MIEX Treatment Efficiency Pedro A. Palomino and Treavor H. BoyerUniversity of Florida, Department of Environmental Engineering Sciences Peak Location Drive DOC vs. Intensity SUVA vs. FI Growing populations are stressing water supplies in many parts of the world. As a result, alternative water sources must be incorporated to meet demand. Dissolved organic matter (DOM) is a major concern in alternative water sources because of the formation of disinfection by-products. With the development of new treatment technologies, such as magnetic ion exchange (MIEX) resin, detailed monitoring is important to understand the treatment efficiency of DOM. In practice, dissolved organic carbon (DOC) and specific ultraviolet absorbance at 254 nm (SUVA) are measured to determine MIEX treatment efficiency. Fluorescence spectroscopy has been shown to be an effective technique to characterize DOM, while its use in drinking water processes is an active research area. (Figure 1) Several waters were studied to explore the differences among the source characteristics and treatability. The goal of this work is to better characterize DOM to improve treatability. The specific objectives are to (1)understand the shift in fluorescence peak location, (2)compare DOC to fluorescence intensity, and (3) compare the SUVA to fluorescence index (FI). Microbial Terrestrial FI = 1.6 FI = 2.1 IHSS Isolate of NOM from Suwannee River Ichnetucknee Spring Figure 4 – Fluorescence standards Rayleigh Line Figure 5 – Fluorescence peak location shift after MIEX treatment Figure 1 – Location of EEM peaks based on literature review (Chen, W.; Westerhoff, P.; Leenheer, J.A.; Booksh, K. Environmental Science and Technology. 2003, 37, 5701 – 5710) Sampling and Analysis Samples were collected between 2/09 and 1/10 from landfills, surface water bodies and a groundwater aquifer. (Figure 2) They were analyzed on a F-2500 Fluorescence Spectrophotometer. (Figure 3) MatLab programs were developed in house to analyze fluorescence data. Sample Cell Figure 6 – DOC and fluorescence peak intensity for microbial and terrestrial regions of both raw and treated samples Figure 7 – SUVA and FI of both raw and treated samples Syn2-4 L4 Syn1 Photo Detector L5 L1 Impact SW2 GW1 SW1 Emission Monochromator SW1: Lake Jesup SW2: St. Johns River Syn1: Santa Fe River Syn2-4: St. Mary’s River GW1: Cedar Key GW L1: Alachua SW Landfill L2-3: Polk Landfill L4: New River Landfill L5: Putnam Landfill L2-3 Excitation Monochromator Peak Location
Microbial peak intensity is better correlated (Table 1)
MIEX preferentially removes the terrestrial component
SUVA vs. FI
Raw SUVA: Synthetic < Surface < Ground < Waste
SUVA and FI are negatively correlated (Table 2)
Fig 3 – Fluorescence Spectrophotometer Table 1 – Correlation between microbial and terrestrial peak intensities versus the raw and treated DOC values Xenon Lamp Figure 3 – Fluorescence Spectrophotometer Schematic Table 2 – Correlation between SUVA and FI value for raw and treated samples Figure 2 – Florida Sampling Map Acknowledgements Thanks to all the students (Stephanie, Sara, Katie, Troy, Paul, Katie, Chris, Krystal, and Jennifer) in Dr. Treavor Boyer’s research group for sample and data collection. Fluorescence measurements could be a better alternative for monitoring MIEX treatment efficiency.