With the strengthening of environmental protection, higher requirements for tail water discharge of aquaculture ponds are put forward. In addition, water resources tax will be introduced soon. New modes should be explored for aquaculture, and the treatment and recycling of aquaculture ponds must be imperative.
The total effective nitrogen content in aquaculture water increased with the increase of breeding quantity. The feed that was fed in pond culture was 5-10% which was eaten by the non fish, and 25-30% in the feed consumed by fish was excreted in the stool.
Nitrogen input, feed 90-98% and nitrogen output, fish account for 20-27%, deposited 54-77% accounted for 54-77%, feed for phosphorus accounted for 97-98%, while sedimentary phosphorus accounted for output of 72-89%, fish output accounted for only 8-24%。 That means that the content of nitrogen and phosphorus in the feed, in addition to a small portion of the feed for the growth of fish, is mostly deposited in the pond, causing waste and pollution。
A large amount of organic matter is contained in the ponds by overfeeding of artificial feed, organic manure and biological excreta. Dissolved organic matter is the nutrient of bacteria, which provides conditions for the breeding and growth of pathogenic bacteria, and increases the possibility of the disease of the cultured organisms. Too much organic matter decomposition needs to consume a lot of oxygen, which makes the pond easy to take place anoxic condition, the water quality is easy to deteriorate, and affects the growth of the culture.
Aquaculture not only takes scientific feeding and management, but also needs to establish pond tail water treatment system, equipped with purification pond, after three level treatment, it is introduced into aquaculture ponds by pump, and then recycled for aquaculture production.
A purification pond cultivation of aquatic plants and herbivorous fish farming; the overflow into the two stage purifying pond, planting a variety of efficient absorption of nitrogen and phosphorus ability of economical aquatic plants and farming silver carp and bighead carp, shrimp, mussels and other aquatic animal, is the most important part in the whole part of the circulating water system after entering the three spillway; Geng purification pond, using aquatic plant photosynthesis inhibition of eutrophic water, and the application of photosynthetic bacteria, bacillus and other microorganisms of clean water, and then through the re introduction of aquaculture pond pump.