The doubling of production scale did not directly cause the total amount of sewage to exceed the design capacity of the sewage treatment facility. In this way, if the capacity of the sewage facilities can still meet the new requirements simply from the perspective of sewage treatment, it is impossible to pinpoint the real reason. The reason for the large increase in the total amount of pollutants is nothing more than the doubling of production scale and changes in the nature of crude oil. Therefore, although the total amount of sewage has not increased in recent years, the concentration of pollutants in the sewage has increased exponentially, which has caused a serious overload of sewage treatment facilities, which is the real reason for unqualified sewage discharge.

       Its sewage treatment measures: Grasp the source to minimize the total amount of pollutants entering the sewage treatment plant. The first is to send all the normal pressure sulfur-containing sewage that has not been stripped to the sewage to the sewage stripping device for treatment; the second is to strengthen the monitoring of the indicators of each sewage point and require that each point not exceed the standard discharge. Grasp the smooth operation to avoid the impact of incoming water on the operation of sewage treatment facilities. The first is to strictly control the temperature of the purified water after the stripping of sewage to ensure that the temperature of the water entering the sewage treatment plant is not greater than 40 ° C; the second is to strengthen the management of alkali residue discharge to ensure that the alkali residue enters the sewage treatment plant after comprehensive treatment. Retrofit sewage aeration tank, replace original double spiral aerator with mesoporous aerator

    (1) Analysis of operation situation Since the total amount of sewage has not reached the design value of sewage treatment, it shows that the residence time of sewage in the aeration tank meets the design requirements. According to the analysis results, the dissolved oxygen concentration of the water in the aeration tank was extremely low. This shows that the oxygen supply in the aeration tank is seriously insufficient, and it cannot meet the normal needs of activated sludge growth at all. There are two possible causes of hypoxia in the aeration tank. One is insufficient oxygen supply; the other is low oxygen utilization. Before determining the transformation plan, the relevant personnel start with a simple test of adjusting the air volume, that is, the standby fan is turned on, the air supply is adjusted, and the change of the dissolved oxygen concentration is analyzed. It is known through experiments that even when two fans are running at the same time, the concentration of dissolved oxygen does not increase significantly, which indicates that insufficient oxygen supply is not the main influencing factor of aeration in the aeration tank.

    (2) The original aerator is a double-helix type. Due to the large air outlet of this aerator, the bubble diameter is also large and the distribution is uneven, resulting in extremely low dissolved oxygen concentration in the water. The utilization rate of oxygen by the air device is 8-9, which not only causes waste of oxygen supply, but also directly affects the growth of microorganisms in the pond.

    Therefore, the sewage treatment system of the petrochemical plant, without any changes to other facilities, has adopted a micro-microporous aerator to replace the original double spiral aerator. The original design has increased by more than three times, and the impact resistance has been significantly improved. After the transformation, the qualified rate of sewage discharge can be increased from the original unqualified to over 95.