Operating Instructions for Aerobic Tank
The main function of the Aerobic Tank is to oxidize and decompose complex macromolecular organics into simple inorganic substances through the process of microbial adsorption, oxidation and reduction in activated sludge under the condition of sufficient aeration and oxygen supply, so as to achieve the purpose of purifying wastewater.
Operating Instructions
1. Adjust the aeration rate according to the specific situation, and adjust the air intake rate by controlling each valve.
2. The aeration tank shall control the process by adjusting the sludge load, sludge age or sludge concentration.
3. The dissolved oxygen at the outlet of aeration tank should be 2mg/L.
4. The activated sludge biofacies, supernatant transparency, sludge color, state, odor, etc. shall be frequently observed, and relevant items reflecting sludge characteristics shall be regularly tested and calculated.
5. For abnormal phenomena such as sludge bulking and sludge floating in sedimentation tank caused by changes in water temperature, water quality or operation mode of aeration tank, the causes shall be analyzed, and the system operation conditions shall be adjusted according to specific conditions, and appropriate measures shall be taken to restore to normal.
6. When the water temperature in the aeration tank is low, appropriate measures should be taken to extend the aeration time, increase the sludge concentration, increase the sludge age or other methods to ensure the sewage treatment effect. The water temperature in the aeration tank shall not be higher than 38 ℃. If it is too high, the water can continue to flow after taking cooling measures!
7. When foam and scum are produced in the aeration tank, the reason shall be analyzed according to the color of foam, and corresponding measures shall be taken to restore to normal. Turn on the defoaming water pump as appropriate and spray defoamer.
8. According to the sludge condition, add the nutrient to the biochemical tank, and generally add the nutrient source according to the ratio of BOD5: N: P ＝ 100:5:1. N source is urea, P source is potassium dihydrogen phosphate.
9. Prevent the biofilm on the air-water interface from being too thick and bulging. Monitor the bubbles on the surface of the daily aeration tank. When there are too many large bubbles covering the tank surface, increase the aeration volume of the fan to flush the bubbles, reduce the bubble volume, and increase the number of bubbles; If the effect of increasing aeration is not good, stop aeration first, wait for anaerobic fermentation under the bubble biofilm in the tank, and then suddenly increase aeration for flushing.
10. Remove excess sludge in time. The "activated sludge" suspended in the contact oxidation tank mainly comes from the fallen and aged biofilm, and the suspended solids not completely separated in the pretreatment stage is also one of the reasons. The small and forgiving free bacteria can flow out with the effluent, while the large blocks that absorb a large number of sand impurities have a large proportion, which are difficult to deposit at the bottom of the pool with the outflow of water. If such large blocks are not discharged from the pool in time, they will gradually self oxidize, which will increase the load of the treatment system. Some of the metabolites are non biodegradable components, which will increase the COD of the effluent, and thus affect the treatment effect. In addition, too much sludge at the bottom of the tank will cause the aerator to be blocked. In order to avoid this situation, we should regularly check whether there is sludge at the bottom of the oxidation tank and whether the concentration of suspended solids in the tank is too high. Once it is found that there is black sludge or the concentration of suspended solids at the bottom of the tank is too high, we should timely use the sludge discharge system in the oxidation tank to discharge sludge. At this time, the method of aeration and sludge discharge can be adopted, and the sludge at the bottom of the tank can be discharged after being loosened by aeration.
11. Regression analysis of the operating data of established biofilm system to maintain high DO shows that the treatment efficiency decreases significantly when the dissolved oxygen (DO) level in the aeration oxidation tank is less than 2mg/L. That is to say, the DO value in the biofilm system should be controlled higher than that in the suspended activated sludge system. Generally, DO in aeration tank should be controlled at about 3-4 mg/L.
12. For daily monitoring, the aeration tank shall be sampled and submitted for inspection once a day, and the test results shall be fed back in time.
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