Study On The COD Removal Technology Of Oil Depot Wastewater

The wastewater of the oil depot is generated from oil tank bottom water, bilge water, tank cleaning water, living water and the rain. All these sources result in the complex composition of pollutants with high COD content. The water features of the product depot can be described as follows: the components of wastewater are complicated; the wastewater for treatment are not continuous and change greatly with no regularity, which is hard to control and deal with. It has become an urgent domestic product problem to reduce COD value, until which meets the national discharge standards of the oil depot.For the features of the depot wastewater, electrochemistry methods are introduced to treat the sewage in this paper. COD is the main evaluation value, which is between 35000-38000mg/L for the original wastewater. After the static experiments, the optimum conditions with COD removal rate 70.84% of Micro-electrolysis method are worked out as follows. The iron and carbon ratio is 2:3, pH value is 4 and experiment time is 60 minutes. Depending on the data obtained from the static experiment, the dynamic experiments were carried out in self-made micro-electrolysis column and the optimum reaction time was worked out. The electrolysis experiments were carried out in self-made electro bath. The optimum conditions of the static experiment were worked out as follows. pH value is 6.1, plate and water quantity ratio is 1/4, reaction time is 80min, electric currency density is 40mA/cm2, and the plate distance is 2cm. The COD removal rate is 71.63% under such conditions. Afterwards, the Orthogonal Experiments of three main factors were carried out and the optimum conditions of the experiments are as follows. The reaction time is 100min, electric currency density is 40mA/cm2 , and the plate distance is 2.5cm. The COD removal rate is 89.1% under such conditions.. In order to resolve the treating limits problem which exists in both methods, these two methods were combined to deal with the wastewater and under the optimum conditions the COD removal rate reached 94.55%. Based on the experiments study, the reaction mechanisms of both electrolytic and micro-electrolysis methods were also discussed in this paper.