At the Laizhou Mingbo Aquatic Products Co., Ltd. breeding base, the reporter found that, unlike the general farms, there was a closed seawater circulating water workshop next to the semi-slip tongue culture workshop. Recirculating aquaculture reduces underground seawater consumption by 95% and only 5% of water is drained compared to traditional farming methods.

The traditional culture is flow-type. The water in the fish pond is drained directly after use. It consumes a great amount of water, drastically reduces the precious underground seawater resources along the coast, and the wastewater from the Mingbo aquaculture workshop flows into the circulating water plant and passes through the solid and liquid. Separation, air flotation, biological purification, degassing, disinfection, and oxygenation were reinjected into the culture tanks.

The reporter saw that the body of water purified from the water flowed into a dissolved oxygen pool. The technician designed a nanometer oxygen diffuser in the oxygen tank to add liquid oxygen to the water. The liquid oxygen and the water body are folded back and mixed by the convection of the water vapor, so that the oxygen gas bubbles are constantly pressed by the water below the water surface, and finally all dissolved in the water body, so that the dissolved oxygen content in the water body reaches the standard of high-density breeding water. After returning to the oxygenated water body, the water circulation treatment has been completed and flowed back to the culture pond.

Li Bo, general manager of Mingbo Aquatic Products Co., Ltd. introduced that closed seawater recirculating aquaculture system is a central government modern agricultural production development fund (high-quality fish) industry project, compared with the "greenhouse + deep well seawater" factory farming model, from 0.5 Kilograms of juveniles were cultured to 1.75 kilograms of commercial fish, the production cycle was shortened from 12 months to 6 months, the rearing density was increased from 5 to 25 fish per square meter, and the underground seawater consumption was reduced by about 95%; Compared with the “industrial equipment thermostat + greenhouse” farming method in some areas, the consumption of electricity and coal decreased by 69% and 93% respectively, and the consumption of water resources decreased by 99%. Compared with the international advanced level, the system cost is only similar to that of foreign countries. About 1/3 of the system, the cost of operation and maintenance is only about 1/5 of that of similar foreign systems.

Due to the fully enclosed design, the heat loss of the aquaculture water in the recycling process is reduced to a minimum; in the winter when the temperature is low or in summer, the water temperature of the aquaculture water can be adjusted by adding a small amount of high or low temperature seawater. It ensures that the temperature of the aquaculture water body is always at a suitable temperature, which creates the conditions for shortening the production cycle of the cultured species and raising the density of the culture.

According to the experts of the Shandong Provincial Institute of Marine Fisheries, the closed seawater recirculating aquaculture model can adapt to the large-scale breeding of major domestic marine aquaculture species such as semi-smooth tongue gills, turbot, gingiva, grouper, and river bream, and it has popularization and applicability. Good, cost-effective systems, low operating costs, significant energy-saving effects, unit density and other advantages of farming. It can be vigorously promoted along the coast.