The photo-catalysis technology has been effective and efficient in the reduction of chemical oxygen demand (COD) in wastewater. Titanium dioxide (TiO₂) is one of the most commonly used photo-catalyst and plays significant a major role in reducing COD concentration levels in wastewater. The polyaniline (PANI) was synthesized using an in-situ chemical oxidative polymerization method. This work focused on the reduction of COD in distillery wastewater using an annular rector under batch mode. The influent was diluted at different concentration levels of about 5 ml/l, 10 ml/l and 20 ml/l. The pH condition was adjusted at pH of 1.00, 2.00, 3.00, 4.00 and 5.00 in order to evaluate its effect on the COD reduction efficiencies. The TiO₂/PANI was prepared in different ratios and was allowed to mix with the wastewater for a good homogeneity mixture. The experiments were carried out at ambient temperature (± 25 ºC), whereby solutions were pumped into the photo reactor (annular) inserted with a 25 UVC lamp. The results indicated that the concentrations of all three solutions without the catalyst decreased from 355 mg/l, 655 mg/l and 837 mg/l to 325 mg/l, 572 mg/l and 820 mg/l, respectively. The solutions containing the catalyst also decreased from 325 mg/l, 572 mg/l and 820 mg/l to 344 mg/l, 475 mg/l and 752 mg/l, respectively. The results showed an increasing reduction trend of 2%, 2%, 19%, 20% and 26 % when the catalyst was used at pH of 6.0. It can be concluded that photo-catalysis can reduce COD in distillery wastewater when running under both recirculation and continuous. It can therefore be recommended that higher adjustments of pH can be done, and the process can be operated for more than 2 hours to further enhance the COD reduction in distillery wastewater.