DPO Pure Oxygen Aeration System

      Pure oxygen aeration is an activated sludge biological treatment process that uses pure enriched oxygen instead of air for aeration.The basic principle of pure oxygen aeration technology is to use cryogenic air separation and pressure swing adsorption for oxygen production to produce high-purity oxygen, and to replace air aeration with pure oxygen with an oxygen content volume fraction of over 90%.

      The mechanism of pure oxygen aeration process and air aeration activated sludge method is identical. Both processes leverage the aerobic microorganisms on the organic matter in the sewage biochemical reaction to purify the sewage. The decomposition of organic matter in the sewage relies on the activated sludge (aerobic microorganisms) uniform dispersion and full contact with the sewage to complete.

      The difference is that the former is to charge pure oxygen into the wastewater, while the latter is to charge air into the wastewater. One of the characteristics of the oxygen aeration method is that the treatment efficiency is significantly higher than that of the air method. The aeration time required for the same wastewater treatment to the same level is generally only about 1/3 of that of the air method, which significantly improves the oxygen transfer rate, thus increasing the concentration and activity of aerobic microorganisms and significantly improving the shortcomings of the traditional activated sludge method.

      Product Characteristics

        1. Compared to air aeration, pure oxygen has the following characteristicsHigh oxygen transfer rate. In the water temperature of 20 ℃, the concentration of pure oxygen is 4.7 times of air oxygen concentration (21%), and the oxygen partial pressure of pure oxygen is 4.7 times of that of the air. In the water, the saturation concentration of dissolved oxygen is also 4.7 times higher than the air, so the dissolution rate of pure oxygen transfer to clear water is also 4.7 times higher than the air, higher than 4.7 times in the sewage. The residence time required for pure oxygen aeration is only about 1/3 of air aeration. Open microbubble oxygen aeration and underwater impeller test results show that the oxygen utilization rate of pure oxygen aeration is 80% to 90%, while the general oxygen utilization rate of air blast aeration is only 12%. Oxyfuel aeration has a high impact load resistance and stable water quality.
        2. Less residual sludge. Under pure oxygen conditions, the organisms are in a state of high endogenous metabolism, i.e., self-oxidation, and sludge production is greatly reduced, resulting in about 25% less residual sludge than the air aeration activated sludge method.
        3. Improved sludge settling performance. The oxygenation capacity of pure oxygen aeration is improved, which reduces the power input to the aeration tank and the shear force on the active biofloc. The high dissolved oxygen concentration inhibits the growth of filamentous bacteria that cause sludge expansion. The SVI of pure oxygen aeration method is 30 to 50.
        4. Facilitates biological nitrification. The high dissolved oxygen concentration of pure oxygen aeration can achieve complete nitrification of NH3-N in the wastewater.
        5. High efficiency of wastewater treatment. The high sludge concentration and high sludge load of pure oxygen aeration makes its volume load reach 3-5 times of air aeration, and the volume of the aeration tank can be greatly reduced, and the energy consumption is reduced by about 25%.
        6. No odor emission. Fast decomposition of VOCs and complete reaction.

      The difference between the two processes is that the pure oxygen aeration process uses pure oxygen while the air aeration process uses air, i.e., the oxygen concentration of the gas source is different. The high oxygen dissolution rate and oxygen concentration of the pure oxygen aeration process speeds up the metabolism of microorganisms, thus increasing the number of microorganisms, i.e. the concentration of sludge, accelerating the reaction rate and greatly improving the efficiency of wastewater treatment.

      Process Advantages

      The main advantages of the pure oxygen aeration activated sludge method are as follows:

      1. The oxygen utilization rate can reach 80% to 90%, while the blower aeration system is only about 10%.
      2. The MLSS value of the mixture in the aeration tank can be as high as 4000~7000mg/L, which can improve the volume load of the aeration tank.
      3. The SVI value of the mixture in the aeration tank is low, generally below 100, and sludge expansion occurs less frequently.


      Sewage Treatment Plant in Zhejiang Province

      Project Scale:30,000 t/d
      Type:Industrial Wastewater

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