This experiment is dedicated to second-year and above undergraduates who are in their experimental session of the analytical chemistry course. Grouped students are required to use a TiO[subscript 2] photocatalytic oxidation process to treat the methanol-containing wastewater that resulted from their previous HPLC experiments. Students learn to assemble a specified apparatus for a chemical reaction and analytical methods for the determination of environmental pollutants and reaction intermediates. The comprehensive experiment can give students a deep insight into application of several instruments (COD analyzer, UV-vis, GC-FID, and GC-MS) and the principle of photocatalytic oxidation reaction. Meanwhile, upon the completion of the experiment, students not only become aware of the wastes they generate but also understand how chemistry can be utilized for environmental remediation.