The main pollutants in aquaculture wastewater include ammonia nitrogen, nitrite, organic pollutants, phosphorus, and fouling organisms. Research has confirmed that during the breeding process, only 1/4 to 1/2 of the phosphorus and nitrogen that enter the breeding water as feed can be absorbed and utilized by the breeding animals, while the rest is dissolved in the water. The breeding variety, feed type, feeding method, and management level all affect the water quality of aquaculture effluent. Inappropriate feeding can cause serious pollution exceeding the standard in aquaculture water bodies. If the aquaculture effluent is not treated in a timely and effective manner, it will pollute the surrounding water environment after discharge, leading to a series of fish diseases and ecological problems.

Types of tailwater pollutants:

The tail water of aquaculture is composed of various insoluble pollutant particles and soluble nitrogen and phosphorus substances. Among them, nitrogen, phosphorus, and various compounds are the main components of polluted water bodies

1.1 Insoluble particles

Pollutant particles in tailwater generally refer to dissolved feed and excrementAnd sludge, particle size ≤ 1 mm. These insoluble pollutants have an impact on fishSignificant harm, infection of the respiratory system, increased risk of stress response,Affects its growth and development. At the same time, these pollutants can cause water to become richNutritionism provides a breeding ground for bacteria and viruses in water bodies;If left uncleaned for a long time, it will lead to oxygen deficiency in the water body, and anaerobic bacteria will metabolize itHarmful hydrogen sulfide to fish can cause gill inflammation, ultimately leading toFish die.

1.2 Nitrogen containing compounds

The main components are ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, etc,If a certain concentration is reached, it will cause a large number of animals and plants in the water bodyPoisoned death. Due to the high solubility of ammonia in fat, it enters the fish bodyAfterwards, it damages its epidermal cells and increases the concentration of ammonia in the blood of fish,At the same time, it destroyed the oxygen carrying capacity, causing fish to lose appetite and suffocateWaiting for phenomena.

1.3 Phosphorus containing compounds

Both feed and fish feces can produce phosphorus containing compounds. waterPhosphorus in is divided into two types: soluble and insoluble. One in the excrement of fishThere are generally insoluble granular phosphorus, and the water body does not have autonomous separationPhosphorus will accumulate in water bodies, polluting them and ultimately causing pollutionEutrophication of water bodies.

Flowchart of grouper aquaculture wastewater treatment:

2、 Working principle of fiber turntable:

CLZL typeRotary filterInstalled vertically by a series ofComposed of a rotatable filtering turntable, the turntable is installed on the central drum. Each turntable consists of two semi-circular fan blades. Install a mesh stainless steel filter cloth membrane on the component, and the average pore size of the filter cloth can be selected according to the actual requirements of the customerTake 5 μ m-200 μ m. The incoming water flows through a free fall and enters the filtering turntable from the central drum, passing through and filtering from the inside out. The filtered liquid then flows out from the outlet of the structure. During the filtering process, the turntable begins to be in a stationary state.

Solid substances in the inflow are intercepted by the filter cloth and deposited on it. As the filtration time increases, the liquid level of the central drum rises. When the preset maximum liquid level is reached, the turntable begins to slowly rotate, and the backwash water pump extracts filtered water through the flushing nozzle to flush the solid substances deposited on the filter cloth. Throughout the entire operation, filtration is continuous, even during the cleaning process. The flushed slag water mixture is discharged from the system through the slag discharge groove installed in the middle of the central drum.

In recent years, China's aquaculture industry has developed rapidly. If a large amount of aquaculture wastewater cannot be scientifically and effectively treated, it will cause huge environmental problems and ultimately affect the healthy development of the aquaculture industry. Common physical, chemical, and biological treatment technologies have their own advantages and limitations in the treatment of aquaculture wastewater, and should be selected according to the actual situation. Biological treatment technology, as a hot topic in current aquaculture wastewater treatment, can effectively improve the comprehensive treatment efficiency of wastewater, save water resources, and prevent secondary pollution. The combined application of physical, chemical, and biological treatment technologies can achieve more ideal results. Continuously improving and innovating existing wastewater treatment technologies is of great significance for achieving healthy, green, and sustainable development of the aquaculture industry.