WO2021227534A1

WO2021227534A1 - Biological combined purification pond for freshwater aquaculture tail water

Info

Publication number: WO2021227534A1
Application number: PCT/CN2020/141237
Authority: WO
Inventors: 江兴龙; 郭少鹏
Original assignee: 集美大学
Priority date: 2020-05-09
Filing date: 2020-12-30
Publication date: 2021-11-18
Also published as: CN111422991A

Abstract

A biological combined purification pond for freshwater aquaculture tail water. The pond comprises a first-stage treatment unit pond (1) and a second-stage treatment unit pond (2), wherein the first-stage treatment unit pond (1) and the second-stage treatment unit pond (2) are connected. Fish, which have different feeding habits and inhabit different water layers, are released into the first-stage treatment unit pond (1), with the types of the fish and the released mass ratio thereof being as follows: filter-feeding fishes : omnivorous fishes : detritivorous fishes : herbivorous fishes = (0.8-0.9) : 6.0 : (0.5-0.9) : (2.7-2.2). Aquatic plants (22) and biological membrane water purification bars (23) are provided in the second-stage treatment unit pond (2); the seedling adding amount of the aquatic plants (22) being 0.2-0.8 kg/m²; and 5-20 groups of biological membrane water purification bars (23) being provided per mu according to the water surface area of the pond.

Description

Biological combination purification pond for freshwater aquaculture tail water

Technical field

The invention specifically relates to a biological combined purification pond for freshwater aquaculture tail water.

Background technique

my country is a large aquaculture country, with aquaculture production accounting for about 68% of the world's aquaculture production, of which, pond aquaculture production accounts for about 45%. However, the tail water of pond culture and the tail water of factory farming are basically discharged directly without treatment. Because the tail water of aquaculture generally contains high nitrogen and phosphorus, it has caused different degrees of eutrophication pollution to the surrounding water environment. In order to protect the ecological environment of the water area, the water quality of the discharged water can meet the relevant national environmental protection requirements, such as the "Freshwater Pond Aquaculture Water Discharge Requirements" (SC/T 9101-2007), the national "Surface Water Environmental Quality Standards" (GB3838-2002) ) Class III water quality standards, etc. Current pond farming tail water or factory farming tail water treatment technology mainly adopts artificial wetland technology, ecological pond technology and comprehensive application of chemically assisted phosphorus removal technology. However, the constructed wetland technology has a large area, and it is prone to substrate clogging in the middle and late stages of operation, secondary pollution caused by plant decay, and reduced treatment effects that affect the quality of the effluent; ecological pond technology has a large area, and the treatment effect varies greatly. , The effluent water quality is relatively unstable and other problems; the chemical reagent-assisted phosphorus removal technology also has problems such as large area, high operating cost, poor stability of the treatment effect, and easy to cause secondary pollution. Many aquaculture farms have failed to carry out tail water discharge treatment due to land area restrictions and high treatment costs, polluting the surrounding water environment or facing the problem of forced suspension of production due to non-compliance with environmental protection standards.

technical problem

The technical problem to be solved by the present invention is to provide a biological combined purification pond for freshwater aquaculture tail water, which solves the current problem of high investment and operating costs for nitrogen and phosphorus removal from aquaculture tail water, and has low investment and operating costs. Energy saving, no secondary pollution and easy management.

Technical solutions

The present invention is realized as follows: a biological combined purification pond for freshwater aquaculture tail water, the biological combined purification pond includes a first-stage treatment unit pond, a second-stage treatment unit pond, the first-stage treatment unit pond, and a second-stage treatment unit pond. The secondary treatment unit is connected to the pond.

The first-stage processing unit ponds are stocked with fishes of different feeding habits and different habitats. The types of the fishes and their stock quality are as follows: filter-feeding fish: omnivorous fish: scraping fish: herbivorous fish Sex fish = 0.8-0.9: 6.0: 0.5-0.9: 2.7-2.2.

The second-stage treatment unit pond is provided with aquatic plants and a biofilm water purification grid, and the seedling amount of the aquatic plant is 0.2~0.8kg/m2; the biofilm water purification grid is based on the pond water area per mu Set 5~20 groups.

Furthermore, the filter-feeding fish stocked in fingerlings per mu of water surface are as follows: 100-150 silver carp, 50-60 bighead carp, with an average size of 200-300g/tail; omnivorous fishes are as follows: carp 1600- 2000 fish, average size 100-150g/tail, crucian carp 1200-1500, average size 50-75g/tail; scraping fishes are as follows: carp 800-1200, average size 25-50g/tail; herbivorous fish : 200-250 grass carp, with an average size of 500-600g/tail.

Further, the aquatic plant is a combination of Eichhornia crassipes or Eichhornia crassipes and Hydrilla verticillata, Valeriana spp, Myriophyllum spp, Ceratophyllum spp, Porphyra spp, and Elodea; each group of said biofilm net The length of the water grid is 20-40m, the height is 0.7-1.4m, and the distance between each group of the biofilm water purification grid is not less than 1m.

Furthermore, after 6-10 months of breeding of the fish species, the fishes can be harvested and released in rotation, that is, fishes that reach the market specifications are fished and marketed in an appropriate amount, while continuing to replenish the fish species to maintain the first-level treatment The stock of fish in the unit pond is greater than the total weight of the initially stocked fingerlings.

Further, from July to October, the densely growing aquatic plants are salvaged every week and put into the first-level treatment unit pond for feeding herbivorous fishes to control the growth density of aquatic plants.

Furthermore, from November to March of the following year, the aquatic plants whose stems and leaves begin to turn yellow are salvaged every week and put into the pond of the first-level treatment unit for feeding herbivorous fish.

Furthermore, in November, a batch of herbivorous fishes with an average tail weight of more than 1 kg was added to feed the aquatic plants recovered from the pond of the second-stage treatment unit.

Furthermore, the first-stage treatment unit pond is dredged with a mud suction pump every winter.

Beneficial effect

The present invention has the following advantages.

The invention solves the current problems of high investment and operation cost for nitrogen and phosphorus removal from aquaculture tail water, and has the advantages of low investment and operation costs, energy saving, no secondary pollution, simple management and the like. Compared with the currently used constructed wetland technology to treat pond culture tail water (the area of constructed wetland ≥ 15% of the total pond culture area), the area is reduced (the area of the present invention ≤ 10% of the total pond culture area) , And can avoid the easy clogging of the substrate in the middle and late stages of the operation of the constructed wetland method, and the problem of secondary pollution caused by the release of nitrogen and phosphorus due to plant corruption.

The invention does not use chemical reagents, and avoids the problems of high operating cost and easy to cause secondary pollution in the chemical reagent precipitation method. The technology of the present invention uses a biological combination purification method to construct a secondary treatment unit pond to treat the aquaculture tail water, so that the nitrogen, phosphorus and organic matter in the aquaculture tail water can be used by a variety of fishes, water hyacinth and other aquatic plants and The assimilation, transformation and degradation of biofilm bacteria, and the re-feeding and utilization of aquatic plants by grass carp, etc., and finally being marketed by fish products, thereby removing nitrogen, phosphorus and organic substances in the aquaculture tail water from the water and realizing the tail water The waste that pollutes the water body is finally transformed into high-quality aquatic animal protein for human consumption through the food chain and food web constructed by this technology. After the aquaculture tail water is treated with this technology, the discharge of suspended solids, pH, ammonia nitrogen, total nitrogen, total phosphorus, permanganate index, BOD5, COD and other water quality indicators can meet the "Freshwater Pond Aquaculture Water Discharge Requirements" (SC/ T 9101-2007) the first-level discharge standard, or the national surface water third-class water standard, meets the environmental protection discharge requirements.

Description of the drawings

Hereinafter, the present invention will be further described with reference to the accompanying drawings and embodiments.

Figure 1 is a schematic diagram of a biological combined purification pond for freshwater aquaculture tail water according to the present invention.

Figure 2 is a side view of the second-stage treatment pond of the present invention.

Embodiments of the present invention

The present invention will be further described below in conjunction with specific embodiments.

Examples.

1. Refer to Figure 1, the first-level treatment unit pond 1, and various types of fish combination polyculture purification pond; the pond can be a single or 2~3 parallel combination, according to the proposed treatment of tail water farms expected fish and shrimp breeding peak period The total weight of the storage pond is generally based on the expected total weight of fish and shrimp per 20-40 tons, with 1-1.5 acres of water surface, the pond depth of 2.0 meters, and aerators; mixed aquaculture of various fishes is carried out. Carry out the polyculture of ponds with multi-trophic levels, different feeding habits (filter feeding, omnivorous, scraping, herbivorous), and no feed for fish in different habitats.

(1) The first-level treatment unit pond 1 puts filter-feeding fish (feeding on phytoplankton, zooplankton and organic particulate matter) per mu of water surface: silver carp (Hypophthalmichthys molitrix) 100-150, bighead carp (Hypophthalmichthys nobilis) 50-60, average size 200-300g/tail; omnivorous fish (feeding on residual bait, organic debris and benthic animals): carp (Cyprinus carpio) 1600 -2000 tails, average size 100-150g/ tail, crucian carp (Carassius auratus) 1200-1500, average size 50-75g/tail; scraping fish (feeding on residual bait, organic debris, organic particulate matter, adherent organisms and benthic organisms): carp (Distoechodon sp. or Xenocypris sp. ) (Such as Distoechodon compressus, Xenocypris davidi Bleeker, etc.) 800-1200, average size 25-50g/tail; herbivorous fish (feeding on residual bait, organic debris, plant ): Grass carp (Ctenopharyngodon idellus ) 200-250 tails, average specification 500-600g/tail.

(2) The types of polyculture fish and the ratio of stock quality are as follows: filter-feeding fish: omnivorous fish: scraper fish: herbivorous fish = 0.8-0.9: 6.0: 0.5-0.9: 2.7-2.2.

(3) No artificial bait is used for the fish to be fed, so as to fully ingest the residual bait, organic debris, organic particles in the tail water, and the plankton formed by the fertile water such as fish manure and dissolved nitrogen and phosphorus in the tail water. Plants, zooplankton and benthic organisms, etc.

(4) Operation principle: The freshwater aquaculture tail water that needs to be treated first flows into the first-stage treatment pond 1 for treatment. The residual bait, feces and organic particles in the tail water can be stocked omnivorous fish (carp, crucian carp), herbivorous Fish (grass carp), filter-feeding fish (silver carp, bighead carp) and scraping fish (silver carp) eat food. At the same time, the dissolved nitrogen and phosphorus in the tail water can be absorbed and assimilated by phytoplankton, phytoplankton and zooplankton. It can also be ingested and used by fish. Therefore, in the first-stage treatment pond 1, the residual bait in the tail water, the organic particulate matter in the feces, the organic suspended matter, the soluble nitrogen and phosphorus, etc., can be ingested by fish or used indirectly, thereby being removed in large quantities. In addition, some suspended matter and large particulate matter in the aquaculture tail water also precipitated and settled at the bottom of the pond. The treated water flows from the upper water outlet 11 of the first-stage treatment pond 1 to the water inlet 21 of the second-stage treatment unit pond 2 by itself.

In addition, the general fish species can be reared for 6-10 months after the stocking, that is, depending on the situation, the fish of the larger size can be fished and marketed in an appropriate amount. At the same time, the fish species must be kept in the pond. The stock of fish is greater than the total weight of the initial stocked fish species. In November, a batch of larger grass carp (with an average tail weight of more than 1kg grass carp) can be restocked in an appropriate amount to fully eat water hyacinths and other aquatic plants taken from the pond of the second-level treatment unit. The mud suction pump is used to moderately dredge the silt every winter, and the silt can be accumulated on the pond ridge or transported for agricultural planting.

2. Refer to Figure 1-2, second-level treatment unit pond 2, aquatic plants 22 + biofilm water purification grid 23 combined ecological pond. Through the establishment of aquatic plants 22 + biofilm water purification grid 23 combination ecological ponds to synergistically remove nitrogen and phosphorus, the ponds can be single or 2~3 ponds in parallel or in series. According to the expected total weight of fish and shrimp storage ponds during the peak period of the breeding farm, 1.2-2.0 acres of water surface and 1.5-2.0 meters of water depth are set for every 20-40 tons of expected output, and no aerator is equipped.

(1) Planting water hyacinth (Eichhornia crassipes) and other aquatic plants according to the water area of the second-level treatment unit pond 2 Plant water hyacinth (more than 70%), with Hydrilla verticillata (Hydrilla verticillata), Vallisneria (Vallisneria nuttallii). sp.), Myriophyllum sp., Ceratophyllum sp., Potamogeton sp., Elodea nuttallii.

(2) Set up biofilm water purification grid 23 according to the water area of the pond 2 of the second-level treatment unit, and set 5-20 groups of biofilm water purification grid 23 per mu, each group is 20m in length and 0.7-1.4m in height. The biofilm water purification grid 23 is vertically suspended from about 20cm below the water surface of the pond. The upper and lower nylon ropes 24 at both ends of the biofilm water purification grid 23 can be fixed in the pond by wooden stakes (steel piles) 25. The rope is tied with a float (using foam plastic, etc.) every 3~5m to provide buoyancy (the buoyancy of a single float is 6~10kg), and the spacing between each group of biofilm water purification grids 23 arranged horizontally is not less than 1m.

(3) Operation principle: (a) Eichhornia crassipes and other aquatic plants grow by assimilating a large amount of nitrogen and phosphorus in the water, and also absorb suspended solids in the water; a large number of bacteria (including nitrifying bacteria, denitrifying bacteria and polymerizing bacteria) are attached to their roots. Phosphate bacteria, etc.), and the roots secrete oxygen and organic carbon (organic acid, etc.), which further promote the assimilation, transformation and degradation of nitrogen, phosphorus and COD.

(B) The biofilm water purification grid can form a large area of biofilm and also absorb suspended solids in the water; use the huge amount of bacteria on the biofilm (including nitrifying bacteria, denitrifying bacteria, phosphorus accumulating bacteria and other heterotrophic bacteria) Bacteria, etc.) Carry out the assimilation, transformation and degradation of nitrogen, phosphorus and COD in water.

(C) A large number of denitrifying bacteria on the biofilm can not only use the organic matter in the water body, but also use the organic carbon (organic acid, etc.) secreted by the roots of water hyacinth and other aquatic plants, and the decomposition of water plants such as water hyacinth. The organic matter undergoes a denitrification reaction, so that the nitrate nitrogen in the water finally forms nitrogen, which is emitted from the water body, further reducing the concentration of nitrate nitrogen and total nitrogen in the water.

In addition, from July to October, aquatic plants such as water hyacinths that have grown too densely can be manually salvaged every week and placed in the pond of the first-level treatment unit for feeding and reusing the cultivated grass carp to control the water hyacinths. Reasonable growth density of lotus and other aquatic plants. From November to March of the following year, water hyacinths and other aquatic plants whose stems and leaves start to turn yellow are usually salvaged every week and put into the pond of the first-level treatment unit to feed the cultivated grass carp to prevent water hyacinths and other aquatic plants A large amount of death and corruption release the nitrogen and phosphorus contained in the water.

In short, the present invention mainly constructs a secondary tail water treatment unit pond to treat the culture tail water, and the culture tail water flows into the first level treatment unit pond, and uses a variety of polyculture fish to fully consume the residual bait and organic debris in the culture tail water. The phytoplankton, zooplankton and benthic organisms formed after the waste water, fish manure and dissolved nitrogen and phosphorus in the tail water, and the formation of fertile water. The tail water after the primary treatment then flows into the pond of the secondary treatment unit. The established aquatic plant + biofilm water purification grid combination ecological pond is used to further treat the dissolved nitrogen and phosphorus, COD and suspended solids in the water. A lot of aquatic plants such as ophthalmology assimilate and absorb nitrogen and phosphorus in the water, and utilize a large number of bacteria on the roots and biofilms of aquatic plants to assimilate, transform and degrade nitrogen, phosphorus and COD in the water. So as to finally achieve the effects of dephosphorization and denitrification, degradation of organic matter and reduction of suspended solids concentration.

3. Implementation effect.

Using the above method, the constructed biological combination purification pond of freshwater aquaculture tail water is used for advanced treatment of nitrogen, phosphorus and organic matter in eel aquaculture tail water. The result data is as follows.

.

Remarks: Influent refers to the aquaculture tail water, and effluent refers to the discharged water after treatment in the treatment tank.

In summary, the discharged water after aquaculture tail water is treated by a biological combination purification pond of freshwater aquaculture tail water constructed by the present invention, its ammonia nitrogen, total nitrogen, total phosphorus, permanganate index, BOD5 and COD, etc. It meets the Class III water quality standard in the National Environmental Quality Standard for Surface Water (GB3838-2002), and also meets the first level discharge standard specified in the Freshwater Pond Aquaculture Water Discharge Requirements (SC/T 9101-2007). It shows that the secondary treatment unit pond constructed by the application of the biological combined purification method of the present invention has good denitrification, phosphorus removal and organic matter degradation capabilities.

Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described by us are only illustrative, and are not used to limit the scope of the present invention. The equivalent modifications and changes made by the skilled person in accordance with the spirit of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

A biological combination purification pond for freshwater aquaculture tail water, characterized in that: the biological combination purification pond comprises a first-stage treatment unit pond, a second-stage treatment unit pond, the first-stage treatment unit pond, and a second-stage treatment unit pond. Unit ponds are connected;

The first-stage processing unit ponds are stocked with fishes of different feeding habits and different habitats. The types of the fishes and their stock quality are as follows: filter-feeding fish: omnivorous fish: scraping fish: herbivorous fish Sex fish = 0.8-0.9: 6.0: 0.5-0.9: 2.7-2.2;

Pond the secondary processing unit is provided with a fresh water aquatic plants and biofilm gate, the delivery amount of aquatic plants seedlings 0.2 ~ 0.8kg / m 2; the biofilm pond water purifier according to the gate area per Set 5-20 groups per mu.
The biological combination purification pond for freshwater aquaculture tail water according to claim 1, characterized in that: the filter-feeding fishes put into the fish species are as follows: 100-150 silver carp, 50-bighead carp according to each acre of water surface. 60 fish, average size 200-300g/tail; omnivorous fishes are as follows: carp 1600-2000, average size 100-150g/tail, crucian 1200-1500, average size 50-75g/tail; scraping fishes are as follows : 800-1200 carp, average size 25-50g/tail; herbivorous fish: 200-250 grass carp, average size 500-600g/tail.
The biological combination purification pond for freshwater aquaculture tail water according to claim 1, wherein the aquatic plants are water hyacinth or water hyacinth and Hydrilla verticillata, Vallisneria, Myriophyllum, Ceratophyllum The combination of the genus, Pseudomonas, and Elodea; the length of each group of the biofilm water purification grid is 20-40m, the height is 0.7~1.4m, and the spacing between each group of the biofilm water purification grid is not Less than 1m.
The biological combination purification pond for freshwater aquaculture tail water according to claim 1, characterized in that: after the fish species are put in for 6-10 months, the fish can be caught and released in rotation, that is, the fish that reach the market specifications Appropriate fishing and marketing of fish species are carried out while continuing to replenish the stocking of fish species to maintain the stock of fish in the pond of the first-level treatment unit greater than the total weight of the initially stocked fish species.
The biological combination purification pond for freshwater aquaculture tail water according to claim 1, characterized in that: from July to October, the densely growing aquatic plants are salvaged every week and put in the pond of the first-level treatment unit , Used to feed herbivorous fish to control the growth density of aquatic plants.
The biological combination purification pond for freshwater aquaculture tail water according to claim 5, characterized in that: from November to March of the following year, the aquatic plants whose stems and leaves begin to turn yellow are salvaged every week, and put to the first The first-level treatment unit pond is used to feed herbivorous fishes to prevent the decay of decayed stems and leaves in the water and the release of nitrogen and phosphorus in the water body.
The biological combination purification pond for freshwater aquaculture tail water according to claim 6, characterized in that: in November, a batch of herbivorous fishes with an average tail weight of more than 1 kg was added to fully feed from the second stage The aquatic plants picked from the pond of the processing unit.
The biological combined purification pond for freshwater aquaculture tail water according to claim 1, characterized in that the first-stage treatment unit pond is dredged by a mud suction pump every winter.