Wastewater Challenge: Effects of Inexpensive Filtration Methods on Caffeine Removal

Overview

Objectives/Goals The objective of my experiment was to determine if an expensive filter would be effective at removing drug residues from wastewater, using caffeine as a model. In this experiment, a UV spectrophotometer was used to test for absorbance at the expected wavelength for caffeine. Methods/Materials Approximately 80 test samples were evaluated. Samples of Diet Pepsi were filtered through activated charcoal pellets, zeolite, ceramic, or a Brita filter. In another trial, dilutions of soda were first treated with alum, then filtered through fine sand. Some samples were also filtered through activated charcoal. Results In dilutions of 3.3 milligrams of caffeine per 100 milliliters, the absorbance at 274 nanometers was reduced by 20% using activated charcoal and by 25% with zeolite. Treatment with alum alone reduced the "caffeine" (absorbance at 274 nm) by 37%. Adding activated charcoal filtration decreased the "caffeine" (absorbance at 274 nm) a total of 45%. Conclusions/Discussion By using flocculation and activated charcoal filtration, it appeared possible to remove nearly half the "caffeine" (as represented by the peak at 274 nanometers) in a test sample. One difficulty with my experiment was that the absorbed UV radiation at 274 nanometers may have represented compounds other than caffeine. For example, there seemed to be another compound present in the Caffeine Free Diet Pepsi that absorbed ultraviolet radiation at 274 nanometers. Still, my results indicated it might be possible to remove harmful substances in wastewater through relatively inexpensive filtering methods.

Awards (1)

• Honorable Mention

Competition history

• CSEF 2009 Environmental Engineering (Junior Division Only) · Entry J1128

Resources

• CSEF project summary ↗

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