Increasing DO by Nanobubbles Technology is a potential solution for the aquaculture industry in the future. Why increase DO (DO is dissolved oxygen content)? What methods are there to increase DO in water? So what is DO increase with Nanobubbles technology? What are the advantages of using Nanobubbles technology?

DO, also known as dissolved oxygen content, is an important factor that directly determines the growth and development of aquatic species. Especially in the aquaculture pond system, the DO concentration in the pond is greater than 5 mg/l, the fish grows and develops well. Shrimp grow and develop well when the water has a DO index of 3mg/l. Conversely, if DO < 3 mg/l, it will affect the physiology of the cultured organisms, the survival rate will decrease, the growth will be slow, the disease is easy, the pond is not productive, the fish eat less or eat slowly leading to excess feed. Feeding in ponds, high feed coefficient (FCR), accumulation of toxic gases, long farming time, high cost of using drugs and chemicals… Currently, industrial aquaculture has high stocking density and little change. In addition to the amount of oxygen consumed by organisms, the amount of oxygen needed to decompose waste and toxic gases in the pond is very large. Therefore, ensuring the supply of oxygen in the water is very important. It is necessary to calculate and arrange suitable aeration devices, in order to maintain aquatic respiration and ecological balance in the pond.

To ensure the demand for dissolved oxygen in pond water, it is necessary to take measures such as raising algae, installing water fans and aeration systems.

Algae are a natural food source for fish and shrimp and are also an important source of dissolved oxygen through photosynthesis. Algae growth is strong or weak depending on the nutrient content in the water. So in order to maintain and stabilize the amount of algae in the water, it is necessary to use some types of cereal powder … to cause water color, increase the number of algae when the pond is poor in nutrients. At the same time, it is possible to use chemicals such as CaO lime, chlorine-containing products to reduce algae in the pond when they thrive, to avoid the phenomenon of oxygen deficiency and water pollution when the algae die.

Consists of a shaft connected to an electric motor or motor shaft, on which there are 10-15 propellers, the propeller can be plastic or porcupine. With a solid structure, When operating the fan, the water can create a lot of water bubbles, thus increasing the amount of dissolved oxygen. Cheap plastic blade fans are widely used in intensive and semi-intensive shrimp farming households. In addition to the advantages such as providing oxygen for farmed shrimp, creating a flow that stimulates the movement of shrimp and collects excess waste in an area in the middle of the pond, while helping drugs and chemicals to be evenly distributed in the water. pond. However, using a blade fan will not bring a lot of dissolved oxygen to the bottom to provide shrimp and decompose organic matter.

Increase DO By Air Blowing System

In aquaculture ponds, to increase the dissolved oxygen content, aerators are often used to bring compressed air into the water at a certain depth. The gas bubbles that form (from a few millimeters to a centimeter in size) exchange oxygen with water as they move from the bottom of the water column to the top of the water and then burst when exposed to air. The larger the size of the air bubbles, the faster the moving speed, so the efficiency of dissolved oxygen enrichment for the pond water environment is not high if the air bubbles are not fine enough.

SOME Aerators

There are many methods to increase DO in popular ponds today, such as using water fans, aerators to increase oxygen for ponds. Here are some methods to increase DO

Air Mixing Ejector is a simple vacuum forming device, using Venturi principle, the speed of water through a narrow area will reduce the pressure, create a vacuum, the gas pushed into the ejector will mix evenly with the water. go out. This is a perfect device to be applied, used for gas mixing to increase the DO index “Dissolved oxygen in water”. In addition, the ejector also has an equally important effect that it releases toxic gases in the water.

Ejector also has many other effective applications: aspiration of ozone gas and chemical solutions to raise pH, flocculation, sterilization, etc. Ejecter is a specialized accessory that comes with medium and large capacity industrial ozone machines (All types). ozone machine with ozone capacity from 15g O3/h or more). Has the effect of mixing Ozone gas into the water pipe at the force of gravity to help the water mix with ozone, preventing water backflow into the Ozone machine.

When the Ejector is installed in the Ozone supply system, the Ozone gas source is injected directly into the water stream through the 1-way air valve. Due to the structure of the pipe (the cross-section of the pipe changes), the water flow pulls the source air stream and is expanded and accelerated when it reaches the large section of the pipe, tearing the air bubbles. The gas source is easily dispersed in water, creating conditions for ozone to dissolve quickly. Ozone has the effect of disinfecting, oxidizing pollutants and at the same time increasing the DO content in water.

The air delivery foam tube/disc is a device with hundreds of tiny holes. In fact, the air distribution disc/tube is often used with the blower. The air from the blower is led through the pipe system and connected to the disc/blower placed at the bottom of the tank or pond. In this system, the gas distribution disc will have the effect of dispersing oxygen into the water.

The advantage of this system is that it can both operate and feed shrimp and fish;

The dissolved oxygen content in water reaches over 5mg/l;

Less stress for shrimp and fish and no fear of electric shock because the air blower is located on the shore.

The air distribution system with a blower disc is often used to expel chlorine gas after disinfection in order to reduce the time to wait for water to be recirculated into the pond / culture tank, and also to increase DO before supplying it to the pond / tank.

However, due to the high investment cost and easy to clog, the system has to be cleaned many times, so this system is mainly used in shrimp hatcheries and high-tech models in greenhouses with a small area.

A method using an aerator capable of creating micro- (<50um in diameter) and nano-sized air bubbles less than 50 nm in diameter. While ordinary air bubbles are large, lasting only about 5 seconds until they rise to the surface and burst, micro/nano air bubbles are capable of submerging and floating in water, so they last longer. about 5 hours (micro bubbles) ~8 hours (nano bubbles), more soluble in water, so DO increases.

Generates a lot of oxygen, which is a destructive factor for bacteria and fungi that cause dangerous animal diseases; creating excess oxygen that precipitates alum in water such as iron alum, aluminum alum and heavy metals;

Neutralize ammonia and other toxic gases (chemical or biochemical reaction with the participation of aerobic bacteria);