A Study of the Efficiency of Ozone for the Removal of BOD and Organic Matter in Shrimp Pond Effluents

Abstract

     The application of ozone at a rate of 0.017, 0.034 and 0.073 mg/l/min resulted in the increase of the oxidation-reduction potential and total residual oxidant (TRO) of the effluents. The increase in oxidation-reduction potential and TRO of the effluents was significantly higher when higher dosages of ozone were applied. Treatment of shrimp pond effluent with ozone at the dosages of  0.034 and 0.073 mg/l/min resulted in complete removal of BOD₅ within 48 h. A longer treatment period of 144 h was needed to remove all the BOD₅ of the effluent at a lower ozone dosages of 0.017 mg/l/min. The highest percentage of total organic carbon (27.5-38.2%) removal was observed  within a  period of 4 h. Subsequently, the removal rate of total organic carbon was significantly lower. Bromate was detected at 120 h in the effluent treated with 0.017 mg/l/min of ozone. At higher ozone dosages of 0.034 and 0.073 mg/l/min bromate was detected at 72 h. Concentrations of bromate were between 0.0001 and 0.0006 mg/l which were lower than maximum allowable concentration in the WHO standard.