Huizhou: Ecological shrimp farming in high-level ponds, zero discharge of tail water

"Shrimp cultured with probiotics + circulating water tastes fresh and sweet, like wild." On March 15, in Renshan Town, Huidong County, Huizhou City, Guangdong Bigao Biotechnology Co., Ltd.'s breeding base, the company's general manager Manager Gao Zhanyuan pointed to the shrimps thrown up by the shrimp pond and told the "Ocean and Fisheries" reporter that through the use of microbial purification technology, this high-level pond shrimp breeding base has achieved zero discharge of tail water, and it is currently the only one in Huizhou that has no tail water discharge. The high-level pond ecological circulation breeding base in the mouth.
 
In May last year, Guangdong Bigao Biotechnology Co., Ltd. and the Municipal Fisheries Research and Promotion Center, a public institution affiliated to the Huizhou Agriculture and Rural Bureau, jointly carried out "antibiotic-free, odorless, zero tailwater discharge" probiotic ecological breeding in the breeding base of Renshan Town. test. At present, three kinds of breeding have been tested. Among them, the first experimental breeding is to raise P. monodon, with a per mu yield of 6,000 catties and a harvest size of 37-40 heads/catties. The currently cultivated species is Penaeus vannamei, and the seedling time is mid-to-late January. Although the weather is hot and cold in February and March, the shrimp are growing well. The reporter saw at the scene that the shrimp was already the size of a little finger, and it is expected that the shrimp will be released one after another in mid-April.
 

▲ Prawns
 
"Bacteria" cultivation + microbial purification,
 
Realize the recycling of aquaculture tail water
 
This base has a total breeding area of ​​20 mu, and has set up 15 breeding ponds of different specifications, with a seedling density of 360,000/mu. The reporter saw at the scene that the aquaculture water in the pond was oily green, the water color was relatively transparent, and there was no obvious odor in the winter shed. "Shrimp farming requires water, and the quality of water quality directly affects the growth and survival rate of shrimp." Gao Zhanyuan said that when the water is clear, there will be no fish. The water for shrimp farming must cultivate a good algal phase to provide shrimp with Biological bait, but the premise is that the problem of algae aging and shrimp feed residue and shrimp excrement must be solved. The previous practice was that after the algae were aged, they were killed and discharged by chemical substances, and then the water body was disinfected, detoxified, and algae cultivated. In the breeding base, Bigao adopts the "bacterial phase" breeding technology, that is, the self-developed probiotics continue to treat the breeding water, so that the feed residues and shrimp excrement in the water can be decomposed and utilized by probiotics, ensuring that The bacteria in the water are dominated by probiotics, which realizes the dynamic balance of the bacterial phase and the algal phase in the aquaculture water. The problem is solved, and the aquaculture water quality is excellent and stable. Anti-, odorless, ecological breeding effect.
 
Through the use of microbial purification treatment, the base has realized the recycling of aquaculture tail water. It is reported that the base implements four-level treatment of tail water. After the aquaculture tail water is discharged into the collection tank, the sewage is first disinfected with bleaching powder and spectral bactericide; and then the ammonia nitrogen and organic load of the water body are reduced through microbial treatment technology. Gao Zhanyuan explained that the biotransformation of organic substances in water by adding functional microorganisms from external sources can quickly reduce the content of ammonia nitrogen, nitrite and hydrogen sulfide in the water; after precipitation, the aquaculture tail water enters the biological purification tank and is put into Probiotics further treat the water body. After the aquaculture tail water has been treated to meet the standard, it is returned to the reservoir for use as aquaculture pond water. By continuously circulating water and discharging tail water, the ammonia nitrogen concentration in the water body is reduced, and fresh water is allowed to continuously enter the aquaculture pond.
 

▲ The base implements four-level treatment of aquaculture tail water
 

▲ Reservoir
 
The water consumption of probiotic circulating water treatment is only one third of the water consumption of traditional high-level pond aquaculture. In the first two weeks, there is no need for drainage in the system. From the third week, drainage is carried out every day, and the discharged tail water is microbially purified and recycled. The drainage volume is 500 cubic meters in the third week, 1100 cubic meters in the fourth week, and about 1500 cubic meters per week thereafter. In order to adapt to future development, large-scale water treatment land is currently planned in the base: 8 mu of sewage collection tank, 4 mu of biological purification tank, 2 mu of water storage tank, etc. According to the current design plan, it can meet the requirements of more than 50-60 mu. The breeding area will be expanded in the future.
 
It is suitable for the new requirements of environmental protection,
 
Reduce cost and improve quality to raise good shrimp
 
With the country's increasing emphasis on water ecological environmental protection, the issue of aquaculture tail water discharge has received great attention from all parties. Under the mandatory requirements of environmental protection related policies and regulations, aquaculture discharge requirements are becoming more and more strict. In November 2021, Guangdong Province issued the "Three-Year Action Plan for Upgrading and Renovating Green Development of One-million-mu Aquaculture Ponds in the Pearl River Delta", which clearly stated that it will take three years to complete the upgrade and transformation of one-million-mu aquaculture ponds and tail water treatment in 9 cities in the Pearl River Delta.
 
"Through the 'bacterial phase' aquaculture technology and microbial purification treatment technology, we have solved the environmental protection problem of the tail water of high-level pond shrimp farming." Gao Zhanyuan told reporters that the discharged tail water has no peculiar smell after being treated with probiotic bacteria, and it has been independently obtained by a third party. Professional testing institutions have confirmed that the treated tail water contains 1.22 mg/L of nitrogen and 0.361 mg/L of phosphorus, and all indicators have reached the emission standards. The technology has also greatly reduced the cost of farming. Through the action of probiotics, not only biological bait is cultivated for aquaculture water, but the input of feed and health care products is reduced, and the utilization rate of feed is also improved. According to statistics, under the existing breeding conditions, the bait coefficient is low, the feed-to-meat ratio is reduced by about 2 percentage points, and the water discharge in one breeding cycle is reduced by one-third, and the breeding cost is reduced by nearly 30% to 40% compared with the traditional breeding technology. %.
 

▲ Breeding pond
 
The "bacterial phase" aquaculture technology has improved various indicators of the aquaculture water. Good water is good for cultivating shrimp, and the high-quality water environment also improves the immunity of shrimp and reduces the use of plant protection products. It can be said that the new technology has completely achieved antibiotic-free farming, not only the product safety is effectively guaranteed, but also the survival rate and quality of shrimp are also significantly improved. It is understood that during the breeding cycle, the loss of shrimp is small, and the survival rate reaches more than 90%. In February this year, the weather was cold in spring. On February 20, the temperature in Huizhou, Guangdong once dropped to 6°C. Many shrimp farms suffered heavy casualties. However, due to the construction of winter sheds in the Bigao breeding base, the water quality in the pond remained stable, and the immunity of shrimp Strong, without any wear and tear, successfully avoided the adverse effects of the cold spring on the shrimp farming.
 
Text: Gao Xiaoxia, Yu Xingzhu Photos: Lv Huadang