The electricity consumption of the aerator accounts for 60 ~ 70% of the total electricity consumption of the sewage treatment plant, which means that the electricity of the sewage treatment plant is mainly consumed in the aerator system process of the activated sludge system in the second-stage biochemical treatment. Disc aerator equipment is particularly important in the biochemical treatment system. Its quality is not only related to the degree of microbial degradation of organic matter in the aeration tank, but also directly affects the operation cost of the entire sewage treatment system. Therefore, it has always been an important issue in the research of sewage treatment, and the improvement of microporous aerator equipment and the development of new aerator equipment have become more popular in domestic and foreign research.
1. Oxygen utilization rate of microporous aerator
There are many complicated factors that affect the oxygen utilization rate of aeration equipment. The factors that affect the oxygen utilization rate may have the following two points. On the one hand, with the same amount of circulating water, with the addition of the gas supply, the turbulence intensity of the gas It will also be added, resulting in the increase of the rising speed of the micro-bubbles from the aerator, which will reduce the contact time between the gas and the water body. If the gas turbulence is too large, the bubbles will be unevenly distributed in the water body, forming a coalescence of the bubbles And overflow the water surface, making the air not fully utilized, thereby affecting the utilization rate of oxygen.
Second, the aspects that should be considered in the purchase of diaphragm aerators
1. Treatment effect of diaphragm aerator
The removal rate of CODc in the aeration tank of the disc aerator is more than 80%, the average removal rate of 30 days reaches 85.8%, the removal rate of B0Ds is more than 90%, and the average removal rate reaches 92.79%. The activity of the activated sludge is very good.
2. Oxygen supply ability of rubber membrane microporous aerator
Oxygen utilization and power efficiency are the primary goals to measure the aerator's ability to maintain. With the addition of the service area of the microporous aeration head, the degree of turbulence of the liquid composition will be weakened, so that the appearance update rate of the gas-liquid phase is reduced. In practice, the working medium is a mixture of mud and water. In the process of turbulent compressed air, not only the mass transfer of oxygen is improved, but also the microorganisms can directly use the oxygen in the bubbles, and the utilization rate of oxygen is added again.
3. Need to consider the stirring capacity of the microporous aerator
In terms of the stirring capacity of the disc aerator, the micro-bubbles rise spirally from the bottom of the pool. During the ascent, the pool water spirally stirs, which increases the chance of gas-liquid contact and improves the efficiency of oxygen mass transfer The device has a certain driving force in the direction of its jet, which plays the role of the propeller in the traditional oxidation ditch, together with the hydraulic mixing of the circulating water pump, so that the incoming water can be quickly diluted, adding the resistance of the aeration tank Impact load capacity.
4. Energy consumption of aerator
The power efficiency of the microporous aerator is high. The microporous aerator has an average electrical treatment of CODa of 1.57 kg per kilowatt, and the BODs of 0.93 kgo. The treatment of electricity for other external aerators can be far higher than the micropore. Aerator.