Abstract
Chemo-Autotrophic Activated Carbon Oxidation (CAACO) system was used for the treatment of tannery waste water. It employs activated carbon-immobilised sulphate reducing bacteria for the removal of dissolved organics in wastewater under oxidizing environment. The wastewater characteristics such as COD (1689 mg/L), BOD (377 mg/L), sulphate (915 mg/L) and sulphide (184 mg/L) were applied at an hydraulic loading rate of 0.7376 m
/m
/day and surface loading rate of 0.2438 m
/m
/day to CAACO reactor at 30°C and at atmospheric pressure. The removal of COD, BOD, sulphide and sulphate was 87%, 96%, 100% and 40% respectively after 2 hours of oxidation. The oxidation of dissolved organics in wastewater was accomplished by passing air at flow rate 3 L/min and at pressure 0.5 kg/cm
through CAACO reactor. The effect of variables COD loading, O
/COD, O
/(COD-BOD
), COD/S
–, (COD-BOD
)/S
– and [(COD-BOD
–(COD-BOD
]/S
– on rate and percentage removal of COD from tannery wastewater was determined.