CN106698816A - Enhanced denitrification wastewater treatment method and device for circulating water culture system - Google Patents

Abstract

The invention discloses a waste water enhanced denitrification treatment method and device for a circulating aquaculture system. The steps are: A. the waste water is filtered through a mechanical grid of all stainless steel structure; B. the treated waste water is lifted into anaerobic ammonia by a water pump Oxidation tank for denitrification treatment; C. The treated wastewater enters the intermediate sedimentation tank to remove suspended solids in the water; D. The treated wastewater enters the composite vertical flow constructed wetland to further remove pollutants in the wastewater; E. After treatment The waste water enters the aeration tank for aeration and oxygenation, and the indicators of ammonia nitrogen, organic matter and suspended solids in the effluent all meet the standards of Class I~II water bodies; the device includes mechanical grilles, water collection wells, anammox tanks, Filler, intermediate sedimentation tank, downflow tank, downflow tank filler, upflow tank, upflow tank filler, downflow tank plant, upflow tank plant, aeration tank. The purification and reuse of aquaculture water is realized, the treatment effect is good, and the maintenance is convenient.

Description

Method and device for enhanced denitrification treatment of wastewater for circulating aquaculture system

technical field

The invention belongs to the technical field of aquaculture wastewater treatment, and in particular relates to a treatment method for enhanced denitrification of wastewater used in a circulating aquaculture system, and also relates to a device for enhanced denitrification of wastewater used in a circulating aquaculture system, which is suitable for most Factory high-density recirculating aquaculture systems, and some rural areas where water resources are scarce and lack or even have no centralized wastewater treatment system.

Background technique

The Recirculating Aquaculture System (RAS) is a farming model that introduces wastewater treatment processes in the aquaculture production process to control water quality, reduce water consumption, and improve product yield and quality. The recirculating aquaculture system maintains a relatively stable ecological environment suitable for the growth of aquaculture objects through the purification and reuse of aquaculture water, reduces or removes organic matter and ammonia nitrogen that are not conducive to aquaculture objects, and enhances the metabolism of fish and shrimp, and improves feed conversion. rate, improve disease resistance, survival rate and growth rate, so as to achieve the purpose of high-density aquaculture while saving water. Adopting the recirculating aquaculture system can also make the breeding process easy to monitor. Through the monitoring and management of the breeding process, the cultured products can more easily meet the international food hygiene standards and ensure that the products can enter the international market smoothly.

Ammonia nitrogen is one of the most important water quality indicators in aquaculture water. Ammonia nitrogen in aquaculture water mainly comes from bait, excrement of aquatic animals and the remains of dead animals and plants. When ammonia dissolves in water, part of the ammonia reacts with water to form ammonium ions (NH ₄ ⁺ -N), and part of it forms hydrated ammonia, also known as non-ionic ammonia (NH ₃ -N). The sum of the two is called total Ammonia nitrogen (Total Ammonia Nitrogen, TAN). The specific form of ammonia in water is closely related to the pH value of the water. Studies have shown that when the water temperature is 20°C and the pH is equal to 7.0, the non-ionic ammonia in the water only accounts for 0.4% of the total ammonia nitrogen, but once the pH is greater than 8, the proportion of non-ionic ammonia to the total ammonia nitrogen will increase with the increase of pH High and rapid increase, the highest can reach more than 80%. Non-ionic ammonia nitrogen is highly toxic to fish. When its concentration in fish blood increases, the pH of the blood rises accordingly, which will inhibit the activity of various enzymes in the fish; At low concentrations, it will also reduce the oxygen transport capacity of the blood, damage the gill epidermis, cause poor oxygen and waste exchange and suffocate, and even cause the death of fish; at low concentrations, it will also reduce the food intake, growth rate and Disease resistance, resulting in slow growth or disease in farmed fish. Since recirculating aquaculture generally adopts a high-density aquaculture model, the amount of bait added in the unit water body and the excretion of the cultured objects are large, which will inevitably cause the concentration of ammonia nitrogen in the aquaculture water to increase and the C/N to decrease. If it is not handled in time, It will affect the yield and quality of aquaculture. Therefore, the accumulation of ammonia nitrogen is an important limiting factor for increasing the breeding density in the recirculating aquaculture model, and the effective removal of ammonia nitrogen in the water is a necessary condition for the normal and efficient operation of the recirculating aquaculture system.

At present, the commonly used ammonia nitrogen removal methods in high-density circulating aquaculture systems include air stripping, ion exchange adsorption, ozone oxidation treatment, submerged plant treatment, microbial treatment, etc. Air blowing is to adjust the pH of the water body, use the gas-liquid phase balance and medium transfer Henry's law, fill a large amount of gas into the aquaculture water body, reduce the partial pressure of soluble gas in the water body, and discharge the NH ₃ dissolved in the water body to achieve the removal of The purpose of ammonia nitrogen. This method has high requirements on the pH of the aquaculture water body. It is difficult to maintain a stable pH that can not only greatly improve the treatment efficiency of ammonia nitrogen, but also satisfy the safety of fish production in the water body. temperature, resulting in slower growth of fish. Ion exchange adsorption is to use the physical characteristics of the exchange medium (zeolite, fluorspar, exchange resin, etc.) to realize the exchange and adsorption of ammonia nitrogen in the aquaculture water, so as to finally achieve the effect of degrading ammonia nitrogen. The problem with this method is that the adsorbent needs to be regenerated frequently, and the waste liquid generated by the regeneration still needs to be treated, which makes the operation difficult and the cost is high. Ozone is a strong oxidant and disinfectant, which can disinfect and remove suspended solids in aquaculture water, and also has a good effect on ammonia nitrogen treatment. Ozone catalytic oxidation can directly convert ammonia nitrogen into N ₂ and discharge the water body, but it is easy to produce some oxidation by-products such as NO ₂ ^- and NO ₃ ^- , which instead increases the nitrate content in the aquaculture water body, and also affects the pH of the water body . The treatment of ammonia nitrogen by submerged plants is to use the nitrogen and phosphorus substances metabolized by cultured fish to carry out photosynthesis through submerged plants to achieve the purpose of degrading ammonia nitrogen. However, the processing efficiency and stability of this method need to be improved, and sometimes supplementary lighting is required underwater, making management and maintenance difficult. Microbial treatment is to use the nitrification of nitrifying bacteria and nitrosifying bacteria to transform ammonia nitrogen in aquaculture water, and it is also a type of ammonia nitrogen treatment technology that is widely used at present. Common microbial treatment processes include contact oxidation, sequencing batch activated sludge (Sequencing Batch Reactor, SBR), cyclic activated sludge (Cyclic Activated Sludge System, CASS), biological aerated filter (Biological Aerated Filter, BAF )Wait. These processes have a common feature, which is the need for aeration equipment, and the price of the aeration fan is relatively high, and the power is relatively large, and its energy consumption accounts for a considerable part of the cost of wastewater treatment.

Anaerobic Ammonium Oxidation (ANAMMOX) process was developed by the Kluyver Biotechnology Laboratory of Delft University of Technology in the Netherlands. Under anaerobic conditions, microorganisms use CO ₂ or HCO ₃ ^- as carbon source and NH ₄ ⁺ -N is an electron donor, NO ₂ ^- -N is an electron acceptor, and NH ₄ ⁺ -N is directly converted into N ₂ , so as to achieve the purpose of denitrification. The anaerobic ammonium oxidation process is generally used to treat wastewater with high ammonia nitrogen concentration, but recently some scholars have found that the anaerobic ammonium oxidation reaction can proceed smoothly under the condition of low ammonia nitrogen concentration, and because the reaction does not require oxygen and additional carbon Therefore, it is very suitable for low-cost denitrification treatment of aquaculture wastewater with low C/N.

Constructed wetland is a sewage treatment resource ecological engineering technology developed on the basis of natural wetland purification function. It has low infrastructure investment, low operating cost, increased green area, improved and beautified ecological environment, relatively simple maintenance and management, and effective treatment. Good and other advantages. Its purification methods include filtration, adsorption, precipitation, ion exchange, plant absorption and microbial metabolism, etc. Through the synergistic effect of physics, chemistry and biology, it can effectively remove suspended solids, organic matter, nitrogen, phosphorus, heavy metals and pathogenic microorganisms in wastewater. Constructed wetlands can be divided into various types according to the flow state of wastewater in wetlands. Among them, Integrated Vertical-flow Constructed Wetland (IVCW) effectively solves the problem with its unique structure and "down-up" water flow. It eliminates the "short circuit" phenomenon that is easy to occur in other types of wetlands, and provides microorganisms with an aerobic-anoxic-anaerobic living environment, which is conducive to the denitrification of wetland systems. At the same time, this technology can make full use of the comprehensive effects of substrates, plants and microorganisms, and has a significant removal efficiency for organic matter and suspended matter in wastewater. In addition, the unique flow pattern and structure of the composite vertical flow constructed wetland form a good nitrification and denitrification functional area, making its removal effect on ammonia nitrogen significantly better than other types of wetlands.

The anaerobic ammonium oxidation process can specifically remove ammonia nitrogen in wastewater, but the purification effect on other pollutants is not ideal. Although composite vertical flow constructed wetlands can comprehensively remove various pollutants in medium and low concentration organic wastewater, the ammonia nitrogen purification effect in high-density recirculating aquaculture wastewater is often high, and its ammonia nitrogen purification effect cannot directly meet the standards for fishery water. Therefore, the present invention integrates the advantages and disadvantages of the two, and proposes a combined treatment process of "anammox + composite vertical flow constructed wetland". The artificial wetland is fully purified, and finally realizes the enhanced denitrification treatment of high ammonia nitrogen wastewater.

Contents of the invention

The purpose of the present invention is to provide a method for the enhanced denitrification treatment of high-ammonia-nitrogen waste water in a high-efficiency and low-consumption circulating aquaculture system. The method is easy to implement and easy to operate. The total nitrogen, ammonia nitrogen and other main water quality indicators in the water can meet the water body standards of Class I~II in the "Fishery Water Quality Standard" (GB11607-1989) or "Surface Water Environmental Quality Standard" (GB 3838-2002), realizing circulating aquaculture The purification and reuse of aquaculture water in the system has a very low treatment cost.

Another object of the present invention is to provide a high-efficiency and low-consumption circulating aquaculture system intensified denitrification device for high-ammonia nitrogen wastewater. The advantages of both, taking into account the enhanced treatment of ammonia nitrogen and the removal of general pollutants, simple structure, low energy consumption, good treatment effect, and convenient use and maintenance.

In order to achieve the above object, the present invention adopts the following technical measures:

A kind of waste water strengthened denitrification treatment method for recirculating aquaculture system, its steps are:

(1) The waste water is filtered through the all-stainless steel structure mechanical grille with a grid gap of 2-4mm;

(2) The wastewater treated in step (1) is lifted into the anammox tank through the water pump. Under anaerobic conditions, the anammox microbial flora uses CO ₂ or HCO ₃ ^- as carbon source, and NH ₄ ⁺ - N is an electron donor, NO ₂ ^- -N is an electron acceptor, and NH ₄ ⁺ -N and NO ₂ ^- -N are converted into N ₂ , so as to achieve the purpose of denitrification;

(3) The wastewater treated in step (2) enters the intermediate sedimentation tank. The intermediate sedimentation tank adopts the form of a vertical flow sedimentation tank, and the surface load is not more than 0.8m ³ /(m ² h), to further remove suspended solids (SS) in the water , the same below), to prevent the clogging of the constructed wetland due to too high SS;

(4) The wastewater treated in step (3) enters the composite vertical flow artificial wetland (composed of a downflow pool and an upflow pool in the attached drawing), and is further degraded and removed under the joint action of wetland fillers, microorganisms and plants Pollutants such as organic matter, ammonia nitrogen and SS;

(5) The wastewater treated in step (4) enters the aeration tank, and the concentration of dissolved oxygen (DO) in the water is increased to more than 3 mg/L by aeration, so as to meet the requirements of fish farming and further remove organic pollutants in the water, The total nitrogen, ammonia nitrogen and other major pollutants in the effluent are effectively removed, and the effluent can reach Class I~II in the "Fishery Water Quality Standard" (GB 11607-1989) or "Surface Water Environmental Quality Standard" (GB 3838-2002) Water requirements.

In the waste water enhanced denitrification treatment method for a circulating aquaculture system according to the present invention, a water collection well is arranged behind the mechanical grid in step (1), and the effective volume of a lift pump (in terms of the lowest design water level) is set in the water collection well is not less than that in the well The maximum water output of one lift pump is 15 minutes, and the number of starts of the lift pump per hour is not more than 3, and the lift pump adopts automatic liquid level control.

In the waste water enhanced denitrification treatment method for a circulating aquaculture system according to the present invention, the aeration system of the aeration tank in step (5) adopts a diaphragm type microporous aeration form, and is supplied with air by a fan, and the water is raised by aeration. DO concentration.

A device for enhanced denitrification of waste water in a circulating aquaculture system, including a mechanical grid, a water collection well, a lift pump, an anammox tank, a combined filler, a water inlet pipe I, a water distribution pipe I, an outlet pipe I, and intermediate sedimentation Pool, water inlet pipe II, water distribution pipe II, downflow pool, downflow pool filler, pipe hole at the bottom of the partition wall, upflow pool, upflow pool filler, water collection pipe, outlet pipe II, downflow pool plant, upflow pool plant , an aeration tank, an aeration system and a blower fan, characterized in that: the mechanical grille is connected to the water collection well, a lift pump is arranged in the water collection well, the lift pump is connected to the water inlet pipe I, the water inlet pipe I enters the anammox tank, and is connected to the water distribution pipe I, the water distribution pipe I is laid at the bottom of the anammox tank, and the upper part of the anammox tank is equipped with a combined filler to improve the denitrification effect of the wastewater. The top of the anammox tank is equipped with an outlet pipe I, and the outlet pipe I enters the intermediate sedimentation tank , the outlet water of the middle sedimentation tank enters the water inlet pipe II, the water inlet pipe II enters the downflow tank, and connects the water distribution pipe II, and the water distribution pipe II is laid on the filling surface of the downflow tank, and at the same time, plants are planted on the downflow tank filling surface, and the downflow tank and The upward flow pool is connected through the bottom tube hole of the partition wall, and the bottom of the partition wall between the downstream flow pool and the upward flow pool has a plurality of tube holes arranged in parallel to ensure that the water flow can enter the upward flow pool from the downstream flow pool; the wetland in the upward flow pool The water collection pipe is laid on the filling surface, and the upward flow pond plants are planted on the filling surface of the upward flow tank. The water collection pipe is connected to the outlet pipe II, the outlet pipe II passes through the wall of the upflow pond and the aeration tank wall, and the outlet pipe II enters the aeration tank The aeration system in the aeration tank adopts the form of microporous aeration, which is supplied by a fan, and the DO concentration in the water is increased through aeration.

The height of the anaerobic ammonium oxidation tank is 3-8m, in which there is a combination of soft filler made of aldehyde fiber and semi-soft filler made of polyethylene, which is filled in a single sheet and in a string, compared to The surface area is 3000-5000m ² /m ³ , after the waste water enters through the water inlet pipe I, it enters the anammox tank through the water distribution pipe I, flows from bottom to top to the top of the anammox tank, is discharged through the outlet pipe I, and enters the intermediate sedimentation tank , the rising flow rate of wastewater in the anaerobic ammonium oxidation tank is not more than 0.5m/h; the volume load of NH ₄ ⁺ -N is not more than 0.5kg/(m ³ ·d), the hydraulic retention time is 8-12h, and the water inlet of the anammox tank Alkalinity adjustment device and heating device should be installed at the place, and heat insulation layer should be added outside the anaerobic ammonium oxidation tank in cold northern regions.

The composite vertical flow constructed wetland consists of water inlet pipe II, water distribution pipe II, downflow pool, downflow pool filler, pipe hole at the bottom of the partition wall, upflow pool, upflow pool filler, water collection pipe, outlet pipe II, downflow The filler in the downflow pool is gravel, which is divided into 3 layers from bottom to top, with particle sizes of 30-50mm, 15-30mm, and 5-15mm; the bottom layer of the upflow pool filler is particle size The gravel is 30-50mm, the middle layer is gravel with a particle size of 15-30mm, the upper layer is a mixed matrix of coarse sand (0.5-2mm), blast furnace slag, and diatomite, and the depth of the pool is 0.8-1.2m. The thickness of the filler is 10-30cm higher than that of the upflow pool, the bottom slope is 0.5%-1%, and the hydraulic retention time is 12-24h. Plants are planted on the surface of the downflow pool and the upflow pool. Water collection pipes are arranged on the surface, a partition wall is provided between the two pools, and pipe holes are provided at the bottom to connect the downflow pool and the upflow pool. The waste water enters from the water inlet pipe II, enters the downflow pool through the water distribution pipe II, passes through the filler of the downflow pool from top to bottom, collects at the bottom of the downflow pool, and enters the upflow pool through the pipe hole at the bottom of the partition wall. In the process, the waste water flows from the bottom to the top through the filling of the upflow pool, and is discharged from the outlet pipe II after being collected by the water collection pipe on the surface.

Compared with the prior art, the present invention has the following advantages and effects:

(1) In view of the characteristics of high nitrogen content and low C/N in circulating aquaculture wastewater, the present invention proposes anaerobic ammonium oxidation + composite vertical flow artificial wetland technology, and realizes the purpose of deep denitrification of wastewater. After the wastewater is treated, the removal rate of the main pollutants in the effluent is above 90%, and the total nitrogen, ammonia nitrogen and other main water quality indicators can all meet the "Fishery Water Quality Standard" (GB 11607-1989) or "Surface Water Environmental Quality Standard" (GB 3838-2002) Requirements for Class I~II water bodies.

(2) The present invention realizes the recycling of aquaculture wastewater, meets the needs of developing aquaculture in areas where fishery water resources are scarce, and also avoids the pollution of the water environment caused by the untreated arbitrarily discharged aquaculture wastewater.

(3) The present invention can efficiently remove ammonia nitrogen in aquaculture wastewater, build a relatively stable ecological environment suitable for its growth for the cultured object, thereby improving the feed conversion rate, disease resistance, survival rate and growth rate of the cultured object. While saving water, realize the purpose of high-density aquaculture.

(4) Wastewater mainly relies on gravity self-flow in the technological process of the present invention, only carried out once lifting in the sump well through the water pump, and only simple aeration system is set in the aeration tank simultaneously, compared with conventional biological treatment process, equipment investment and operating costs are reduced.

Description of drawings

Fig. 1 is a schematic structural diagram of a device for enhanced denitrification of wastewater used in a recirculating aquaculture system.

Among them, 1-mechanical grille; 2-collection well; 3-lift pump; 4-anammox tank; 5-combined packing; 6-inlet pipe I; 7-water distribution pipe I; 8-outlet pipe I; 9 - intermediate sedimentation tank; 10 - water inlet pipe II; 11 - water distribution pipe II; 12 - downflow tank; 13 - downflow tank filler; 14 - pipe hole at the bottom of the partition wall; ; 17 - water collection pipe; 18 - outlet pipe II; 19 - plants in the downstream flow pool; 20 - plants in the upward flow pool; 21 - aeration tank; 22 - aeration system (membrane microporous aeration, average pore 80- 100μm); 23 - fan (ordinary). Arrows are the direction of water flow.

detailed description

The above-mentioned content of the present invention will be further described in detail through the following examples, but it should not be understood that the scope of the above-mentioned subject of the present invention is limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.

Example:

A kind of waste water strengthened denitrification treatment method for recirculating aquaculture system, its steps are:

(1) The waste water first flows through the all-stainless steel structural mechanical grille 1 with a grid gap of 2 or 3 or 4 mm, and then flows into the water collection well 2 after removing water plants, branches and large particle pollutants, and then lifts it to the water collection well 2 by using the lift pump 3 The anaerobic ammonium oxidation pool 4 is used for denitrification treatment of wastewater.

(2) The waste water enters the anammox tank 4 through the lifting pump. In order to make the influent water evenly distributed, the influent adopts a water distribution system (perforated pipe type, DN100 for the main pipe, and DN75 for the branch pipe), and a combined packing is arranged in the anammox tank 4 (It is composed of soft filler made of aldehydic fiber and semi-soft filler made of polyethylene, filled in a single sheet or string, with a specific surface area of 3000-5000m ² /m ³ ), anammox microbial flora ( It mainly includes Planctomycetes, Proteobacteria, Bacteroidete and Nitrospira, among which the Planctomycetes are mainly Candidatus Brocadia and Candidatus Kuenenia, which are anaerobic ammonia The main functional bacteria of oxidation reaction) degrade ammonia nitrogen and organic matter in wastewater through anaerobic ammonium oxidation reaction under anaerobic conditions. Set up an anammox tank with a height of 4m, NH ₄ ⁺ -N volume load of 0.21kg/(m ³ ·d), and hydraulic retention time of 12h.

The combined filler is specifically a combination of soft and semi-soft fillers, filled in a single sheet or in strings;

The anammox microbial flora mainly includes Planctomycetes, Proteobacteria, Bacteroidete and Nitrospira, etc., wherein Planctomycetes are Candidatus Brocadia and Candidatus Kuenenia is the main genus, which is the main functional bacteria of anammox reaction.

(3) The effluent from the anammox tank 4 flows into the vertical flow intermediate sedimentation tank 9 with a surface load of 0.6m ³ /(m ² ·h).

(4) The effluent from the intermediate sedimentation tank flows into the composite vertical flow artificial wetland to further remove ammonia nitrogen, organic matter and suspended matter. The composite vertical flow artificial wetland consists of water inlet pipe II10, water distribution pipe II11, downflow pool 12, downflow pool filler 13, pipe hole at the bottom of the partition wall 14, upflow pool 15, upflow pool filler 16, water collection pipe 17, and outlet pipe II18 , Downflow pool plants 19 and upflow pool plants 20, hydraulic retention time 24h. The depth of the downflow pool is 110cm, the bottom layer is gravel with a particle size of 30 or 35 or 40 or 45 or 50mm, and the thickness is 20cm, the middle layer is gravel with a particle size of 15 or 20 or 25 or 30mm, and the thickness is 50cm, and the upper layer is a particle size of 5 or 10 or 15mm gravel with a thickness of 40cm; the upflow pool is 90cm deep, the bottom layer is laid with gravel with a particle size of 30 or 35 or 40 or 45 or 50mm, and the thickness is 20cm, the middle layer is gravel with a particle size of 15 or 20 or 25 or 30mm, and the thickness is 30cm. It is a mixed matrix of coarse sand (particle size 0.5-2mm), blast furnace slag and diatomite in a certain proportion, with a thickness of 40cm. Typhalatifolia and Agave sisalana were planted on the surface of the downflow pool, and Canna genaralis and Phyllostachys heteroclada were planted on the surface of the upflow pool.

(5) The effluent from the composite vertical flow artificial wetland enters the aeration tank, where an aeration system (membrane microporous aeration, with an average pore size of 100 μm) is installed to increase the dissolved oxygen concentration in the water to above 3mg/L. To further remove organic pollutants, the hydraulic retention time is 2.0h, and the water from the aeration tank flows back to the breeding tank for reuse.

A device for realizing the enhanced denitrification treatment method for circulating aquaculture wastewater, which consists of a mechanical grid 1, a water collection well 2, a lift pump 3, an anammox tank 4, a combined filler 5, an inlet pipe I6, a water distribution pipe I7, an outlet Water pipe I8, intermediate sedimentation tank 9, water inlet pipe II10, water distribution pipe II11, downflow pool 12, downflow pool filler 13, pipe hole 14 at the bottom of the partition wall, upflow pool 15, upflow pool filler 16, water collection pipe 17, outlet The water pipe II18, the plants in the downflow pool 19, the plants in the upflow pool 20, the aeration tank 21, the aeration system 22, and the fan 23 are composed of: the mechanical grille 1 is connected with the water collection well 2, and a lift pump is set in the water collection well 2 3. The lift pump 3 is connected to the water inlet pipe I6, which enters the anammox tank 4, and is connected to the water distribution pipe I7, which is laid at the bottom of the anammox tank 4, and the upper part of the anammox tank 4 is equipped with a combined filler 7. In order to improve the denitrification effect of wastewater, an outlet pipe I8 is set on the top of the anammox tank 4, and the outlet pipe I8 enters the intermediate sedimentation tank 9, and the outlet water of the intermediate sedimentation tank 9 enters the water inlet pipe II10, and the water inlet pipe II10 enters the downflow pool 12, and connects The water distribution pipe II11 and the water distribution pipe II11 are laid on the surface of the filler 13 of the downflow pool, and plants 19 are planted on the surface of the downflow pool filler 13. The bottom of the partition wall of the flow pool 12 and the upward flow pool 15 has a plurality of pipe holes arranged side by side in parallel to ensure that the water flow can enter the upward flow pool 15 from the downstream flow pool 12; Upflow pond filler 16 is planted with upflow pond plants 20 on the surface, water collection pipe 17 is connected to outlet pipe II18, outlet pipe II18 passes through the walls of upflow pond 15 and aeration pond 21, and outlet pipe II18 enters aeration pond 21 for aeration. The aeration system 22 in the air pool 21 adopts the membrane type microporous aeration form, and the air is supplied by the fan 23, and the DO concentration in the water is increased through aeration.

The plants 19 in the descending flow pool are specifically Typha latifolia (Typha latifolia) and sisal (Agavesisalana);

The filler 13 of the downflow pool is gravel, which is divided into three layers from bottom to top, with particle sizes of 30-50mm, 15-30mm, and 5-15mm;

Described upflow pool filler 16 is that the lower layer is the gravel of particle diameter 30-50mm, and the middle layer is the gravel of particle diameter 15-30mm, and the upper layer is coarse sand (particle diameter 0.5-2mm), blast furnace slag, Diatomaceous earth mixed matrix;

The plants 20 in the upflow pond are specifically Canna genaralis and Phyllostachysheteroclada.

Among them, the grid distance of the mechanical grid 1 is not greater than 4mm, and the lift pump 3 is installed in the water collection well 2. The effective volume of the water collection well (measured by the lowest design water level) is not less than the water output of the largest lift pump in the well for 15 minutes, and the lift pump The number of starts is not more than 3, the lifting pump adopts automatic liquid level control, the anaerobic ammonia oxidation tank 4NH ₄ ⁺ -N volume load is 0.21kg/(m ³ ·d), the hydraulic retention time is 12h, and the intermediate sedimentation tank 9 adopts vertical flow type, The surface load is 0.6m ³ /(m ² ·h).

The pipes are all made of UPVC pipes and connected by adhesives. The water distribution pipe I7, the water distribution pipe II11 and the water collection pipe 17 are divided into main pipes and branch pipes, of which the main pipe is DN100, the branch pipe is DN75, and the water distribution branch pipes are 45 degrees downward along the vertical pipe axis Holes are staggered, the hole diameter is 3mm, and the branch pipes of the water collection pipe are evenly opened.

The filler 13 for the downflow pool is gravel, which is divided into three layers from bottom to top, with particle sizes of 30-50mm, 15-30mm, and 5-15mm, and Typha latifolia and Agave sisalana are planted on the surface; The bottom layer of the upward flow pool filler 16 is gravel with a particle size of 30-50 mm, the middle layer is gravel with a particle size of 15-30 mm, and the upper layer is a mixed matrix of coarse sand with a small particle size (0.5-2 mm in particle size), blast furnace slag and diatomite , Canna genaralis and Phyllostachys heteroclada are planted on the surface. The filling thickness of the downflow pool is 10-30cm higher than that of the upflow pool, the bottom slope is 0.5%-1%, and the pool depth is 0.8-1.2m.

Operation mode: intermittent operation, the theoretical hydraulic retention time is 12-24h.

Apply the method and device of the present invention to a pilot test base of a circulating aquaculture system. The test system covers an area of 1500m ² and handles water of 160m ³ /d. Ammonia oxidation tank, combined filler, inlet pipe I, water distribution pipe I, outlet pipe I, intermediate sedimentation tank, water inlet pipe II, water distribution pipe II, downflow pool, downflow pool filler, bottom pipe hole of partition wall, upflow pool, Upflow tank filler, water collection pipe, outlet pipe II, downflow tank plants, upflow tank plants, aeration tank, aeration system and fans. As shown in Table 1, the enhanced denitrification treatment device can effectively remove the main pollutants in circulating aquaculture wastewater, especially ammonia nitrogen and total nitrogen.

Table 1 Pollutant removal rate of main process nodes (average value)

The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the specification only illustrates the principle of the present invention, and the present invention also has various aspects without departing from the scope of the principle of the present invention. Changes and improvements, these changes and improvements all fall within the protection scope of the present invention.

Claims (5)

1. a kind of waste water strengthened denitrification processing method for circulating water culture system, its step is：

A, waste water are all steel construction machine grid filtration of 2-4mm through grid gap；

B, the waste water processed by step (A) enter anaerobic ammonium oxidation tank through water pump lifting, and anaerobic ammonia oxidation microbiological flora exists Under anaerobic condition, with CO₂Or HCO₃ ^-It is carbon source, with NH₄ ⁺- N is electron donor, NO₂ ^-- N is electron acceptor, by NH₄ ⁺- N and NO₂ ^-- N is converted into N₂；

C, the waste water processed by step (B) enter intermediate sedimentation pond, and intermediate sedimentation pond uses vertical sedimentation basin, surface loading No more than 0.8m³/m²H, the suspended solid further gone in water removal；

D, the waste water processed by step (C) enter composite vertical current artificial wetland, in being total to for wet land filler, microorganism and plant Under same-action, organic matter, ammonia nitrogen and SS polluters in further degraded and removal waste water；

E, waste water enter aeration tank by the waste water that step (D) is processed, by be aerated improve oxygen in water concentration to 3mg/L with On, fish culture requirement is met, while the organic pollution further gone in water removal, total nitrogen, ammonia nitrogen and pollutant in water outlet Effectively removed, effluent quality reaches I~II class water body standards；

Mechanical grille (1) sets sump (2) afterwards in described step (A), and elevator pump (3) is set in sump, and sump has Not less than a maximum water yield of elevator pump 15min in well, the number of starts is not more than 3, lifting to elevator pump to effect volume per hour Pump is using automatic liquid level control；

Anaerobic ammonium oxidation tank (4) height 3-8m in described step (B), wherein being laid with by the soft-filler of hydroformylation fibre synthetic fibre material The combined stuffing (5) combined with the semi soft packing of polyethylene material, single sheet, string-like filling, specific surface area 3000- 5000m²/m³, after waste water is entered by water inlet pipe I (6), anaerobic ammonium oxidation tank is entered by water distributor I (7), flow to from bottom to top Anaerobic ammonium oxidation tank top, discharges, into intermediate sedimentation pond (9), waste water upper up-flow in anaerobic ammonium oxidation tank through outlet pipe I (8) Speed is not more than 0.5m/h；NH₄ ⁺- N volumetric loadings are not more than 0.5kg/ (m³D), hydraulic detention time 8-12h；

Waste water in described step (D) is entered by water inlet pipe II (10), and downstream pond (12) is entered by water distributor II (11), Downstream pond filler (13) is passed through from top to bottom, after descending bottom of the flow cell is collected, through in partition wall bottom pore (14) entrance Row stream pond (15), in upstream pond, waste water flows through upstream pond filler (16) from bottom to top, on top layer through receiving water pipe (17) discharged by outlet pipe II (18) after collecting；

Aeration tank (21) aerating system (22) use micro-pore aeration in described step (E), are supplied by blower fan (23), by aeration Improve the DO concentration in water.

2. the device that a kind of waste water strengthened denitrification for circulating water culture system described in claim 1 is processed, it includes machine Tool grid (1), sump (2), elevator pump (3), anaerobic ammonium oxidation tank (4), combined stuffing (5), water inlet pipe I (6), water distributor I (7), outlet pipe I (8), intermediate sedimentation pond (9), water inlet pipe II (10), water distributor II (11), downstream pond (12), downstream pond Filler (13), upstream pond 15, upstream pond filler (16), downstream pond plant (19), it is characterised in that：Mechanical grille (1) It is connected with sump (2), elevator pump (3) is set in sump (2), elevator pump (3) connects water inlet pipe I (6), and water inlet pipe I (6) enters Enter anaerobic ammonium oxidation tank (4), connection water distributor I (7), water distributor I (7) is laid in anaerobic ammonium oxidation tank (4) bottom, anaerobism ammonia oxygen Change pond (4) middle and upper part and lay combined stuffing (5), anaerobic ammonium oxidation tank (4) top sets outlet pipe I (8), and outlet pipe I (8) enters Intermediate sedimentation pond (9), intermediate sedimentation pond (9) water outlet enters water inlet pipe II (10), and water inlet pipe II (10) enters downstream pond (12) And water distributor II (11) is connected, water distributor II (11) is laid in downstream pond filler (13) surface, while downstream pond filler (13) surface grafting downstream pond plant (19), downstream pond (12) are with upstream pond (15) by partition wall bottom pore (14) phase Connection, downstream pond (12) have pore parallel side-by-side to set with the partition wall bottom in upstream pond (15), wet in upstream pond (15) Water pipe (17) is received in the laying of ground filler surface, and water pipe (17) is received in upstream pond filler (16) surface grafting upstream pond plant (20) Connection outlet pipe II (18), outlet pipe II (18) is through upstream pond (15) wall and aeration tank (21) wall, outlet pipe II (18) aeration tank (21) are entered, aerating system (22) is aerated using microporous diaphragm in aeration tank (21).

3. the device that a kind of waste water strengthened denitrification for circulating water culture system according to claim 2 is processed, it is special Levy and be：Described downstream pond plant (19) is common cattail and sisal hemp；Described downstream pond filler (13) is gravel, from Under to being above divided into three layers, particle diameter is respectively 30-50mm, 15-30mm, 5-15mm；Upstream pond plant (20) is canna and water Bamboo.

4. the device that a kind of waste water strengthened denitrification for circulating water culture system according to claim 2 is processed, it is special Levy and be：Described upstream pond filler (16) is the gravel of particle diameter 30-50mm, and middle level is the gravel of particle diameter 15-30mm, upper strata It is coarse sand (particle diameter 0.5-2mm), blast furnace slag, diatomite mixed-matrix.

5. the device that a kind of waste water strengthened denitrification for circulating water culture system according to claim 2 is processed, it is special Levy and be：Described downstream pond filler (13) thickness takes 0.5%-1% than upstream pond filler (16) 10-30cm high, base slope, Pond depth 0.8-1.2m.