The oxygenation principle and rational use of aerators

1. Principle of oxygenation

The impeller aerator is a common and efficient oxygenation equipment. It mainly absorbs water from the lower layer and pushes it out to the surroundings through the high-speed rotation of the impeller, turning stagnant water into running water. In this process, the water under the impeller is strongly stirred, causing water leaps and waves on the water surface, forming a water curtain that can wrap air. As the impeller rotates, negative pressure is formed at the rear of the water-stirring wheel, allowing air to be sucked (dissolved) into the water and immediately stirred into microbubbles that enter the impeller pressure zone, thereby greatly increasing the dissolution rate of oxygen in the air and achieving efficient oxygenation.

The oxygenation effect of the impeller aerator is different under different water loads. Generally speaking, an impeller aerator with a power of one kilowatt can basically meet the oxygenation needs of a 3.8-mu fish pond. When the load area is small, the oxygenation effect is more obvious, because the impeller can stir the water more fully, making the contact area between air and water larger and the oxygen dissolving faster. When the load area is large, the oxygenation effect will be weakened accordingly, but it can still improve the dissolved oxygen condition of the water to a certain extent.

(II) Reasonable use

At noon on a sunny day, the impeller aerator can be properly turned on to give full play to its role in oxygenation, water stirring and aeration. At this time, the temperature difference between the upper and lower water layers in the fish pond is large, and the oxygen in the lower water layer cannot be replenished in time. After turning on the aerator, the upper and lower water layers can be exchanged, the temperature difference and oxygen difference are greatly reduced, and the oxygen in the lower water layer can be replenished in time. At the same time, the stirring effect of the impeller can also accelerate the circulation of pond materials, improve water quality, and reduce the occurrence of floating heads. This measure helps to seize the initiative to improve water quality and create a good living environment for fish.

On cloudy days, due to the weak photosynthesis of phytoplankton, the water in the pond lacks dissolved oxygen, which can easily cause fish to float. At this time, the aerator should be used reasonably according to the specific situation. If it is cloudy the next morning, the aerator should be turned on as soon as possible to directly improve the dissolved oxygen situation in the pond water and achieve the purpose of preventing and saving fish from floating. On rainy days, it is not advisable to turn on the aerator at noon, because turning on the aerator at this time will not only fail to increase the dissolved oxygen in the lower layer of water, but will reduce the oxygen-generating function of phytoplankton in the upper layer, increase the oxygen-consuming water layer in the pond, and accelerate the oxygen consumption rate in the lower layer.

On rainy days, due to the lack of sunshine for a long time, the phytoplankton in the fish pond produces very little oxygen through photosynthesis, so the machine must be turned on in the middle of the night to increase oxygen to prevent fish from dying in the pond. Turning on the machine in the middle of the night can increase dissolved oxygen and relieve floating heads, and it should generally be turned on until sunrise.

In addition, when the water quality is too fertilized after a large amount of fertilizer is applied, the method of starting the machine at noon on a sunny day and starting it in the early morning should be combined to improve the dissolved oxygen conditions in the pond water and prevent floating heads. The use of the aerator is not only related to weather, water temperature, and water quality, but also should be combined with the specific conditions of fish farming. According to the law of dissolved oxygen changes in the pond water, the method and time of starting the machine should be flexibly mastered to achieve the purpose of reasonable use, increased efficiency and increased production.