Ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms

Abstract

The invention provides a livestock and poultry farm ammonia-containing odor treatment and washing liquid regeneration device, and belongs to the field of breeding pollution odor treatment, the livestock and poultry farm ammonia-containing odor treatment and washing liquid regeneration device is characterized in that a first washing assembly is connected with an odor source of a farm, and the first washing assembly removes feed dust in odor to form a first washing liquid; after the second washing assembly is connected to the first washing assembly, the second washing assembly absorbs ammonia gas in the odor and transfers the ammonia gas to a liquid phase, and the second washing assembly oxidizes ammonia in the liquid phase to form a second washing solution; the first settling pond is connected behind the first washing assembly and is connected with a sewage source of the farm, and the first settling pond receives the first washing liquid and the sewage source at the same time for settling and forming first tail water; the circulating assembly is connected behind the first sedimentation tank and is connected with the effluent of the second washing assembly, the circulating assembly mixes the second washing liquid and the first tail water to form second tail water, and the circulating assembly performs denitrification and mud-water separation on the second tail water to form regenerated liquid; the regeneration liquid is conveyed to the first washing assembly and the second washing assembly and used for odor washing.

Description

Technical Field

[0001] The present invention relates to the technical field of odor pollution treatment in farms, and particularly to an ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms. Background Art

[0002] The odor emissions from large-scale farms are large in quantity, low in concentration, and complex in components, and ammonia is the main component of the odor in farming. Currently, the treatment of odors in large-scale farms mostly only considers the removal of components in the odor (such as ammonia), that is, it relies on cheap clean water or chemicals or biological treatment technologies, but these technologies have not effectively combined the physical absorption process of ammonia in the odor with the biological oxidation technology under acidic conditions to achieve the purpose of reducing operating costs or investment costs. Moreover, the current deodorization technologies do not fully consider the proper treatment of the large amount of nitrogen-containing washing liquid generated during the deodorization process, and there are problems of secondary pollution or high disposal costs.

[0003] In view of this, there is an urgent need in the art for a combined process suitable for solving the ammonia-containing odor and the regeneration of its washing liquid in large-scale farms, and this process is expected to solve: (1) the sustainability of ammonia removal in pig farms while solving the difficult problem of washing liquid regeneration treatment; (2) reducing the operating costs of treating ammonia-containing odors and their washing liquids. Summary of the Invention

[0004] In view of this, the present invention provides an ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms, which is used to solve the inherent defects existing in the current odor treatment technologies in farms that rely on single technical means (such as clean water absorption, chemical absorption and oxidation, or biological treatment), as well as the problem of regenerating a large amount of nitrogen-containing washing liquid generated during the deodorization process.

[0005] The technical solution of the present invention is realized as follows: The present invention provides an ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms, including a first washing component connected to the odor source of the farm, and the first washing component removes feed dust in the odor to form a first washing liquid; a second washing component connected after the first washing component, and the second washing component absorbs ammonia in the odor and transfers the ammonia to the liquid phase, and the second washing component oxidizes the ammonia in the liquid phase to form a second washing liquid; a first sedimentation tank connected after the first washing component and connected to the sewage source of the farm, and the first sedimentation tank simultaneously receives the first washing liquid and the sewage source for sedimentation and forms a first tail water; a circulation component connected after the first sedimentation tank and connected to the effluent of the second washing component, and the circulation component mixes the second washing liquid and the first tail water to form a second tail water, and the circulation component performs denitrification, short-cut nitrification and mud-water separation on the second tail water to form a regeneration liquid, and the regeneration liquid is transported to the first washing component and the second washing component and used for washing the odor.

[0006] Based on the above technical solutions, preferably, the first washing component includes a first water curtain wall arranged facing the flowing direction of the odor. The first water curtain wall deodorizes the feed dust in the odor by spraying a water curtain; a first circulation pool is arranged below the first water curtain wall and receives the washing water falling from the first water curtain wall to form a first washing liquid.

[0007] Even more preferably, the second washing component includes a second water curtain wall also arranged facing the flowing direction of the odor. The second water curtain wall absorbs ammonia in the odor by spraying a water curtain; a second circulation pool is arranged below the second water curtain wall and receives the washing water falling from the second water curtain wall; a packing box is arranged in the second circulation pool. The packing box is provided with packing attached with nitrifying bacteria to oxidize ammonia in the washing water to form a second washing liquid.

[0008] Even more preferably, the circulation component includes an adjustment pool connected after the first sedimentation tank. The first tail water in the first sedimentation tank flows into the adjustment pool by gravity, and the second washing liquid of the second washing component is drained and injected into the adjustment pool; a denitrification tank is connected after the adjustment pool and denitrifies the second tail water; a second sedimentation tank is connected after the denitrification tank and separates the mud and water from the denitrified second tail water; a short-term nitrification tank is connected after the second sedimentation and oxidizes ammonia nitrogen in the second tail water to nitrite and separates the mud and water again to obtain a regeneration liquid; a reuse pool is connected after the short-term nitrification tank and receives the regeneration liquid, and fresh water is supplemented to the reuse pool.

[0009] Even more preferably, the washing water used for the first water curtain wall is sourced from the first circulation pool; the washing water used for the second water curtain wall is sourced from the second circulation pool.

[0010] Even more preferably, it further includes a hydrolysis acidification tank connected between the sewage source and the first sedimentation tank. The hydrolysis acidification tank decomposes macromolecular organic matter in the sewage into small molecular substances and converts the hydrolysis products into volatile fatty acids.

[0011] Even more preferably, an alkaline agent is added during the mixing process of the sewage and the first washing liquid in the first sedimentation tank to supplement the alkalinity of the first tail water.

[0012] Even more preferably, control the DO in the adjustment pool < 0.2mg / L, and control the COD / NO3 - -N in the adjustment pool to be 2.0 - 4.0.

[0013] Even more preferably, a number of packing balls are arranged in the packing box. The packing balls are filled with polyurethane sponges and nitrifying bacteria are attached to the polyurethane sponges. The filling rate of the packing box is 20% - 35%, and the filling rate of the packing balls is 30% - 40%.

[0014] More preferably, the volume of the reuse pool is greater than the sum of the volumes of the first circulation pool and the second circulation pool, and the first circulation pool or the second circulation pool has a preset water level; when the water level in the first circulation pool or the second circulation pool is lower than the preset water level, the reuse pool conveys the regenerated liquid to the first circulation pool or the second circulation pool; when the water level in the first circulation pool or the second circulation pool reaches the preset water level, the reuse pool stops conveying the regenerated liquid to the first circulation pool or the second circulation pool.

[0015] The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms of the present invention has the following beneficial effects compared with the prior art:

[0016] The present invention combines the ammonia absorption and biological oxidation processes, creatively develops the concept of "treating waste with waste", and at the same time, based on the anaerobic ammonium oxidation denitrification technology, efficiently removes the nitrogen in the washing liquid and reuses it in the deodorization process, realizing the unity of odor and wastewater treatment, eliminating secondary pollution, and providing a sustainable solution for the removal of ammonia in large-scale farms. It has the following advantages compared with the existing processes:

[0017] (1) The stability of ammonia removal efficiency is higher. When using clean water to absorb ammonia, the absorption efficiency will decrease due to the increase in pH value. In the present invention, after ammonia is transferred from the gas phase to the liquid phase, the hydrolysis process will release OH - , and the nitrifying bacteria attached to the packing can oxidize NH4 + -N as a substrate to NO3 - -N, consuming the alkalinity in the water and generating H + . Since the absorption and biological oxidation processes are carried out synchronously and the generated H + is greater than the OH - generated when ammonia dissolves in water, the dynamic weakly acidic absorption condition of the washing liquid is maintained. By combining absorption and biological oxidation, the dynamic and efficient removal of ammonia is ensured.

[0018] (2) It has better economic benefits. On the one hand, the ammonia removal process adopted in the present invention no longer requires dilute acid chemical agents to remove ammonia, which can greatly save the chemical agent consumption cost during operation. At the same time, the water in the absorption process mainly comes from the washing liquid regeneration system, saving a large amount of clean water. On the other hand, the present invention makes full use of the nutrients (including carbon source, trace elements, phosphorus source, etc.) in the wastewater discharged from the farm and uses the economically good anaerobic ammonium oxidation denitrification technology to remove the nitrogen in the washing liquid, which can greatly save the cost of separately treating the washing liquid wastewater again. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] Figure 1 Schematic diagram of the connection relationship of each component of the ammonia-containing odor treatment device of the present invention;

[0021] Figure 2 Stereoscopic schematic diagram of the packing frame of the present invention;

[0022] Figure 3 Removal performance graph of ammonia in a typical cycle pigsty of the present invention;

[0023] Figure 4 Graph of the change of pH and nitrogen in the washing liquid in a typical cycle of the present invention;

[0024] Figure 5 Removal performance graph of total nitrogen by the washing liquid regeneration system in a typical cycle of the present invention.

[0025] In the figure: 1, odor source; 2, first washing component; 21, first water curtain wall; 22, first circulation pool; 3, second washing component; 31, second water curtain wall; 32, second circulation pool; 33, packing frame; 331, packing balls; 4, sewage source; 5, first sedimentation tank; 6, circulation component; 61, regulation tank; 62, denitrification tank; 63, second sedimentation tank; 64, shortcut nitrification tank; 65, reuse tank; 7, hydrolysis acidification tank. Detailed implementation manners

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] As Figure 1 shown, an ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms of the present invention includes a first washing component 2, a second washing component 3, a first sedimentation tank 5, a circulation component 6 and a hydrolysis acidification tank 7.

[0028] Among them, the first washing component 2 is connected to the odor source 1 of the farm, and the first washing component 2 removes feed dust in the odor to form a first washing liquid.

[0029] The second washing component 3 is connected after the first washing component 2. The second washing component 3 absorbs ammonia in the odor and transfers the ammonia to the liquid phase. The second washing component 3 oxidizes the ammonia in the liquid phase to form a second washing liquid.

[0030] The first sedimentation tank 5 is connected after the first washing component 2 and is connected to the sewage source 4 of the farm. The first sedimentation tank 5 receives the first washing liquid and the sewage source 4 at the same time for sedimentation and forms a first tail water. The first sedimentation tank 5 is a coagulation and flocculation sedimentation tank, which mainly completes the removal step of a small amount of suspended solids in the effluent of the hydrolysis acidification tank 7 and the suspended solids in the first washing liquid. The first sedimentation tank 5 is composed of a coagulation tank, a flocculation tank and a sedimentation tank. The form of the sedimentation tank is not limited specifically and can be a vertical flow sedimentation tank or a horizontal flow sedimentation tank.

[0031] Preferably, conventional medicaments such as refined lime or composite alkali, polyacrylamide (PAM), etc. can be selected for the coagulation and flocculation tank. The dosing concentration depends on the site conditions. The surface loading of the first sedimentation tank should be 0.5 - 1.2m 3 / (㎡·d);

[0032] Preferably, the pH value is monitored by an on-line pH probe and the dosing amount of the alkaline medicament is adjusted. The pH should be 6.5 - 8.0;

[0033] The circulation component 6 is connected after the first sedimentation tank 5 and is connected to the effluent of the second washing component 3. The circulation component 6 mixes the second washing liquid and the first tail water to form a second tail water. The circulation component 6 performs denitrification, short-cut nitrification and sludge-water separation on the second tail water and forms a regenerated liquid. The regenerated liquid is transported to the first washing component 2 and the second washing component 3 and is used for washing the odor.

[0034] The present invention mainly includes two parts: one is the ammonia-containing odor treatment system, including two-stage washing components; the other is the washing liquid regeneration system, including the first sedimentation tank 5, the circulation component 6 and the hydrolysis acidification tank 7. The working process of the whole system is as follows:

[0035] (1) The odor generated from the poultry house and livestock house as the odor source 1 enters the odor treatment room after being led by the exhaust duct and the fan. Two-stage washing components are arranged in the odor treatment room. Specifically, the odor is first preliminarily removed of the feed dust and a small part of the components easily soluble in water in the odor by the first washing component 2, and then enters the second washing component 3 for washing, so that the ammonia in the odor is transferred to the liquid phase, and the ammonia in the liquid phase is oxidized by nitrifying bacteria and consumes the alkalinity in the washing liquid, thus completing the dynamic absorption and oxidation of ammonia.

[0036] (2) The first washing liquid generated during the deodorization process and the sewage after hydrolysis acidification (the sewage source 4 is usually the sewage storage tank of the farm sewage treatment station. The farm sewage treatment station will conduct preliminary treatment on the farm sewage. The sewage has been filtered through a 0.5 mm hydraulic screen, and pig manure and crude fiber have been removed) together form the first tail water and enter the first sedimentation tank 5 (the first sedimentation tank 5 is generally a coagulation and flocculation sedimentation tank). The first tail water will flow into the circulation component 6 by gravity; the second washing liquid will be added to the circulation component 6 as a participant in water quality balancing and form the second tail water. This tail water will successively complete denitrification, — shortcut nitrification, and mud-water separation. The resulting regenerated liquid, a part of which will flow back to the denitrification tank (62) in the circulation component 6 to provide NH4 + -N and NO2 - -N, and the other part of the regenerated liquid will enter the reuse tank 65 and then be transported to the two-stage washing component for cyclic washing use, so as to achieve cyclic regeneration and utilization and realize the purpose of "treating waste with waste".

[0037] In Figure 1 a preferred embodiment shown, the first washing component 2 includes a first water curtain wall 21 and a first circulation tank 22.

[0038] Among them, the first water curtain wall 21 is arranged facing the flow direction of the odor. The first water curtain wall 21 washes the feed dust in the odor through a spray water curtain. The first water curtain wall 21 adopts an intermittent spray or continuous spray method to keep the packing in a wet state, so as to capture and intercept the large-particle dust in the odor components. When spraying intermittently, the on-off ratio of the water pump is 0.2 - 1.0, and the spray liquid-gas ratio should be 0.2 - 0.8 L / m 3 ; the packing used in the first water curtain wall 21 includes, but is not limited to, honeycomb regular polypropylene (PP) packing. The specific surface area should be greater than 250 m 2 / m 3 , the packing thickness should be 450 mm, the empty bed wind speed of the packing should be 0.5 - 2 m / s, and the empty bed residence time of the packing should be 0.5 - 2.0 s.

[0039] The first circulation tank 22 is arranged below the first water curtain wall 21 and receives the washing water falling from the first water curtain wall 21 to form the first washing liquid.

[0040] For the two-stage water curtain walls of the present invention, there are obvious distinctions in their functions: Since the odor emitted from the farm often contains feed dust, etc., the accumulation of feed dust is likely to cause the blockage of the water curtain wall and thus reduce the absorption efficiency. Therefore, the first water curtain wall 21 is mainly used for dust removal, removing large-particle substances, and a small amount of odor components to protect the packing in the second water curtain wall 31 from being blocked; the second water curtain wall 31 is the core unit for ammonia absorption.

[0041] In Figure 1In a preferred embodiment shown, the second washing assembly 3 includes a second water curtain wall 31, a second circulation pool 32 and a packing frame 33.

[0042] Among them, the second water curtain wall 31 is also arranged facing the flowing direction of the odor. The second water curtain wall 31 absorbs ammonia in the odor through the sprayed water curtain. The absorption of ammonia is mainly completed in the second water curtain wall 31. The factors affecting the absorption efficiency mainly include the specific surface area of the packing, the wind speed, the spraying intensity (liquid-gas ratio), the residence time of the empty bed of the packing, and the pH of the absorbent. The water pump of the second-stage water curtain wall operates continuously, that is, the continuous spraying method is realized. The liquid-gas ratio of the sprayed liquid should be 0.2-1.2 L / m 3 ; The packing used in the second water curtain wall 31 includes but is not limited to regular plastic packing, and the specific surface area should be greater than 250 ㎡ / m 3 ³, the packing thickness should be 450 mm - 900 mm, the empty bed wind speed of the packing should be 0.5 - 2 m / s, and the residence time of the empty bed of the packing should be 0.5 - 2.0 s.

[0043] The second circulation pool 32 is arranged below the second water curtain wall 31 and receives the washing water falling from the second water curtain wall 31.

[0044] The packing frame 33 is arranged in the second circulation pool 32, and the packing attached with nitrifying bacteria is arranged in the packing frame 33; at the same time, nitrifying bacteria are also attached to the second-stage water curtain wall 31. The nitrifying bacteria attached to the packing in the packing frame 33 and the nitrifying bacteria attached to the second-stage water curtain wall 31 oxidize ammonia in the second washing water to form a second washing liquid, and the existing form of its nitrogen-containing compounds is mainly NH4 + ⁻-N and NO3 - ⁻-N. The nitrifying bacteria in the second water curtain wall 31 and the packing frame 33 are commercially available. The inoculation amount of nitrifying bacteria in the packing frame 33 and the second-stage water curtain wall 31 is 0.05% - 5% of the volume of the circulation water pool, and the effective viable bacteria count is 5 - 10 billion CFU / mL. During operation, the DO of the second washing liquid is 4.0 - 6.5 mg / L, the COD is 50 - 200 mg / L, the pH is 4.8 - 6.5, the TN should be ≤ 1000 mg / L, and the mass concentration ratio of NO3 - ⁻-N / NH4 + ⁻-N is preferably 1.0 - 1.5.

[0045] In the present invention, by organically combining the physical absorption of ammonia and the biological oxidation technology, the maintenance of a dynamic weak acidic environment (pH < 7.0) is realized, and further the efficient absorption of ammonia and the control of the nitrification process are ensured.

[0046] In Figure 1 a preferred embodiment shown, the circulation assembly 6 includes an adjustment pool 61, a denitrification pool 62, a short-range nitrification pool 64 and a reuse pool 65.

[0047] Among them, the regulating tank 61 is connected after the first sedimentation tank 5, and the first tail water in the first sedimentation tank 5 flows into the regulating tank 61 by gravity, and the second washing liquid of the second washing assembly 3 is drained and injected into the regulating tank 61.

[0048] The denitrification tank 62 is connected after the regulating tank 61 and denitrifies the second tail water. The denitrification tank 62 is a partial denitrification / anaerobic ammonium oxidation (PD / A) reaction tank, and a completely mixed reactor can be used. After the second tail water from the regulating tank 61 enters the PD / A tank, the partial denitrifying bacteria in the tank quickly adsorb and store most of the easily degradable organic matter in the cells, and at the same time use this as a carbon source to quickly reduce most of the NO3 - -N to NO2 - -N; under the condition that both available substrate NH4 + -N and NO2 - -N exist, synchronously, the anaerobic ammonium-oxidizing bacteria (AnAOB) attached to the packing and a small amount of AnAOB in the flocculent sludge convert NH4 + -N and NO2 - -N reduced from NO3 - -N into nitrogen gas, constituting a cycle of one PD / A process. The by-product (NO3 - -N) generated in this process then enters the next PD / A process cycle again with the remaining NH4 + -N, and so on. Under the condition of carbon source limitation, a small amount of denitrifying bacteria in the PD / A can synchronously convert NO x - -N (NO3 - -N and NO2 - -N) into nitrogen gas to achieve the purpose of synergistic denitrification. The mixed liquor volatile suspended solids (MLVSS) in the PD / A tank of the denitrification tank 62 should be 2000-4500 mg / L, the DO in the tank during operation should be <0.1 mg / L, pH 6.5-8.0, and the ORP should be less than 50 mV; the sludge reflux ratio is 50%-150% (the ratio of the sludge return flow from the second sedimentation tank to the PD / A tank to the flow from the regulating tank to the PD / A tank); the AnAOB inoculated packing includes but is not limited to biological ropes, polyurethanes, etc., and the biomass attached to the inoculated packing is not less than 10 mgMLVSS / cm 3 , and the packing filling rate is 20%-45%; the nitrogen loading rate (NLR) of the reactor should be 0.5-2.0 kgN / (m 3 ·d).

[0049] The second sedimentation tank 63 is connected after the denitrification tank 62 and separates the mud and water from the denitrified second tail water.

[0050] The short-cut nitrification tank 64 is connected after the second sedimentation tank 63 to oxidize ammonia nitrogen in the second effluent into nitrite and perform mud-water separation. Specifically, the short-cut nitrification tank 64 is a Membrane Bio-Reactor (MBR) tank, and the inside of the tank is a mixture of flocculent sludge and water, where the flocculent sludge contains ammonia-oxidizing bacteria (AOB) and aerobic heterotrophic bacteria. Under low-oxygen conditions, aerobic heterotrophic bacteria can complete the oxidation of the remaining COD in the water coming from the denitrification tank. Similarly, AOB can also oxidize the remaining NH4 + -N into NO2 - -N. The mud-water separation process in the short-cut nitrification tank 64 is completed by a micron-level MBR membrane module (polymer hollow fiber membrane), that is, the water in the mud-water mixture in the short-cut nitrification tank 64 is forced through the MBR membrane by a water production pump to obtain clear water after sterilization. Part of the clear water is refluxed to the PD / A tank to provide NH4 + -N and NO2 - -N to remove the remaining NH4 + -N in the effluent of the denitrification tank 62, and the other part of the clear water enters the reuse tank 65. The MLVSS in the short-cut nitrification tank 64 should be 2000 - 4500 mg / L; the aeration fan is interlocked with DO control. When continuous aeration is adopted, the DO should be 0 - 0.3 mg / L. When the intermittent aeration mode is adopted, the aeration-stop ratio should be 0.2 - 1.5. The mode of producing clear water during MBR operation is the intermittent mode. The water is produced at a high liquid level (1.0 m above the membrane module), and the water production stops at a low liquid level (0.15 m above the membrane module). The ratio of NO2 - -N to NH4 + -N in the produced water is 1.0 - 1.5. The water production flux during operation should be 10 - 20 L / (㎡·h). The backwashing is an automatic backwashing cycle of 20 - 30 min / 3 - 10 d. The online cleaning agent is sodium hypochlorite with a concentration of 150 - 200 mg / L. The cleaning frequency depends on the operation, generally 15 - 30 d; the water production reflux ratio (clear water refluxed to the denitrification tank 62) should be 100% - 400%.

[0051] The reuse tank 65 is connected after the short-cut nitrification tank 64 and receives the regenerated liquid. At the same time, clear water is supplemented to the reuse tank by an automatic control program to make up for the water loss (such as evaporation, etc.) during the deodorization and recycling regeneration process.

[0052] The absorption and oxidation process of ammonia by the two-stage washing component achieves the removal and conversion of ammonia in the gas phase. However, it generates washing liquid wastewater with a low carbon-nitrogen ratio (COD / TN, C / N). When this wastewater is regenerated using traditional nitrification and denitrification processes, the operating cost is prohibitively high and unacceptable. Therefore, the second part of the present invention is a washing liquid regeneration system, which is a process based on the anaerobic ammonia oxidation denitrification technology to convert the nitrogen in the washing liquid into nitrogen gas, so as to achieve the purpose of denitrification (converting liquid nitrogen into gaseous nitrogen). The specific implementation principle is as follows: The main forms of nitrogen in the washing liquid are mainly NH4 + -N and NO3 - -N. Therefore, by controlling appropriate conditions, a denitrification path mainly based on shortcut denitrification and anaerobic ammonia oxidation with denitrification as an auxiliary can occur in the denitrification tank 62 (PD / A tank). The complete denitrifying bacteria can reduce NO3 - -N and NO2 - -N to nitrogen gas, while the shortcut denitrifying bacteria can reduce NO3 - -N in the washing liquid to NO2 - -N. Then, anaerobic ammonia oxidizing bacteria (AnAOB) use NO2 - -N as an electron acceptor to convert NH4 + -N in the washing liquid into nitrogen gas, and simultaneously produce approximately 0.11×(NO2 - -N + NH4 + -N) of NO3 - -N, completing the first PD / A process; further, the shortcut denitrifying bacteria continue to reduce the NO3 - -N generated during the anaerobic ammonia oxidation reaction process to NO2 - -N. Then, AnAOB uses NO2 - -N as an electron acceptor to convert NH4 + -N in the washing liquid into nitrogen gas, and simultaneously produce approximately 0.11×(NO2 - -N + NH4 + -N) of NO3 - -N, completing the second PD / A process, and repeating the cycle. In addition, the NO2 - -N and NH4 + -N in the regenerated liquid refluxed from the shortcut nitrification tank 64 (MBR membrane tank) are further consumed by AnAOB in the PD / A tank, and the 0.11×(NO2 - -N + NH4 + -N) of NO3 - -N generated in this process then enters the PD / A process and repeats the cycle. It can be found that the regeneration of the washing liquid is completed through the cooperation of the PD / A + MBR system.

[0053] In Figure 1In a preferred embodiment shown, the washing water source for the first water curtain wall 21 is from the first circulation pool 22; the washing water source for the second water curtain wall 31 is from the second circulation pool 32, realizing the recycling of water used in the overall system.

[0054] In Figure 1 In a preferred embodiment shown, it further includes a hydrolysis acidification tank 7.

[0055] Among them, the hydrolysis acidification tank 7 is connected between the sewage source 4 and the first sedimentation tank 5. The hydrolysis acidification tank 7 decomposes the macromolecular organic matter in the sewage into small molecule substances and converts the hydrolysis products into volatile fatty acids. Generally speaking, this process can be divided into two stages, the hydrolysis stage and the acidification stage. (1) Hydrolysis stage: Under anaerobic conditions, microorganisms decompose macromolecular organic matter (such as proteins, starches, celluloses, etc.) into small molecule organic matter (such as fatty acids, monosaccharides, amino acids, etc.) through extracellular enzymes or immobilized enzymes, making it a soluble substance and forming hydrolysis products; (2) Acidification stage: Further, the hydrolysis products are converted into volatile fatty acids (such as acetic acid, propionic acid, etc.) under the action of acidifying bacteria, and at the same time, a small amount of carbon dioxide and hydrogen are generated. The COD of the pig farm sewage quality is 10,000 - 20,000 mg / L, NH4 + -N is 500 - 750 mg / L, NO2 - -N ≈ 0 mg / L, NO3 - -N is 0 - 3 mg / L, TP is 4,0 - 120 mg / L, TN is 550 - 800 mg / L, pH is 7.0 - 7.8, alkalinity is 2,500 - 3,500 mg / L (calculated as CaCO3), and there are rich trace elements; the reaction pH of the hydrolysis acidification tank 7 should be 5.5 - 6.5, the reaction temperature should be 20°C - 35°C, the rising flow rate should be 0.5 - 2.0 m / h, MLVSS should be 2,000 - 4,500 mg / L, HRT is 4.0 - 12.0 h, DO should be < 0.2 mg / L, the organic loading rate (OLR) is 1.0 - 5.0 kgCOD / (m 3 ·d), and the soluble COD (SCOD) in the effluent of the hydrolysis acidification tank 7 should be 6,000 - 15,000 mg / L, and the VFA concentration should not be lower than 1,000 mg / L.

[0056] In the above embodiment, when using clean water as the absorbent, the main characteristics of the washing liquid quality are: containing COD of 50 - 200 mg / L, NH4 + -N is 350 - 600 mg / L, NO2 --N is 400 - 700 mg / L, pH is 4.8 - 6.5, DO is 4.0 - 6.5 mg / L, and there is almost no phosphorus source and trace elements. Under such water quality characteristics, it is difficult to meet the conditions required for the PD / A process. Therefore, in order to achieve this denitrification process, it is necessary to provide available carbon sources, trace elements, phosphorus sources, inorganic carbon sources, appropriate pH (6.7 - 8.0), and an anoxic environment to the biochemical system. The present invention realizes the above requirements by introducing the high-concentration sewage discharged from pig farms after solid-liquid separation into the washing liquid. The specific implementation principle is as follows: (1) The sewage from pig farms contains rich carbon sources, phosphorus sources, trace elements, alkalinity, etc., which can provide suitable external conditions for the microbial processes involved in the present invention; (2) The hydrolysis acidification tank 7 can convert macromolecular organic matters in the sewage from pig farms into short-chain and easily utilizable organic matters (such as volatile fatty acids, VFAs), providing available carbon sources for short-cut denitrifying bacteria and complete denitrifying bacteria; (3) Appropriate amounts of hydrated lime and PAM agents are added to the first sedimentation tank 5 to remove suspended solids in the effluent of the hydrolysis acidification tank and simultaneously increase the pH of the mixed liquid; (4) By controlling the addition ratio of the sewage from pig farms, water quality homogenization can be achieved in the regulating tank 61. The reasons are as follows: First, the sewage from pig farms has a high alkalinity, and after adding this sewage, the overall alkalinity of the mixed liquid can be increased; Second, the addition of sewage without dissolved oxygen will introduce a high concentration of organic matters, which will promote the respiration of aerobic microorganisms and thus quickly consume the dissolved oxygen in the washing liquid discharged from the two-stage circulation tank, creating an anaerobic environmental condition for the subsequent biochemical system; Finally, an appropriate C / N can be adjusted in the regulating tank to meet the carbon source requirements of short-cut denitrifying bacteria and complete denitrifying bacteria, and the denitrification tank can simultaneously generate alkalinity. In addition, in the MBR aeration tank, under low-oxygen conditions, AOB converts the remaining NH4 + -N into NO2 - -N. At the same time, aerobic heterotrophic bacteria can further degrade part of the COD to ensure the effluent water quality. The sterilized clear water obtained after being filtered by the MBR membrane, part of it is recycled to the PD / A denitrification tank 62 to provide NH4 + -N and NO2 - -N for AnAOB, and the other part enters the recycled water tank to supplement the water required in the two-stage circulation tank to achieve an overall closed loop. The sludge generated during the regeneration process enters the pig farm sewage treatment station for unified treatment.

[0057] In Figure 1 In a preferred embodiment shown, alkaline agents are added during the mixing process of the sewage and the first washing liquid in the first sedimentation tank 5 to supplement the alkalinity of the first tail water and remove suspended solids, which can provide a suitable pH value for the operation of the subsequent biochemical unit.

[0058] In Figure 1 In a preferred embodiment shown, control the DO in the regulating tank 61 < 0.2 mg / L, and control the COD / NO3 in the regulating tank 61- -N is 2.0 to 4.0. The core purpose of the regulating tank 61 in the present invention is to balance the water quality. An on-line pH probe, COD, and nitrate nitrogen on-line monitoring instruments are provided in the regulating tank 61 to monitor the water quality.

[0059] In Figure 2 In a preferred embodiment shown, a number of packing balls 331 are provided in the packing frame 33. Polyurethane sponge is filled in the packing balls 331 and nitrifying bacteria are inoculated on the polyurethane sponge. The filling rate of the packing frame 33 is 20% to 35%, and the filling rate of the packing balls 331 is 30% to 40%. The realization principle of the colonization and enrichment of nitrifying bacteria is as follows: Autotrophic nitrifying bacteria are inoculated into the circulating water tank, and carrier packings including but not limited to polyurethane sponge are added to the circulating water tank, and the nitrifying bacteria are gradually colonized and enriched on the carriers of the packing frames in the second-stage water curtain wall and the second-stage circulating water tank; under the condition of poor COD (50 - 200 mg / L) content, the domesticated nitrifying bacteria will occupy the dominant ecological niche and proliferate. At this time, the nitrifying bacteria attached to the packing or the second-stage water curtain wall can oxidize ammonia nitrogen in the liquid phase into nitrate nitrogen, and at the same time consume alkalinity (generate H + ) to maintain the weakly acidic environment of the washing liquid in the second-stage circulating water tank. The principle formula is:

[0060] NH4 + Oxidation:

[0061] NH4 + +1.238O2+0.04HCO3 - +0.161CO2→0.96NO2 - +0.04C5H7NO2+0.919H2O+1.919H + ;

[0062] NO2 - Oxidation:

[0063] NO2 - +0.01NH4 + +0.45O2+0.01HCO3 - +0.01H2O+0.04CO2→NO3 - +0.01C5H7NO2.

[0064] The nitrifying bacteria culture process is mainly divided into two stages:

[0065] The first stage is the colonization stage of nitrifying bacteria: First, the nitrifying bacteria purchased from the market and inorganic nutrient agents (carbon source, nitrogen source, phosphorus source, etc.) are mixed in 1m 3The volumetric container is activated for 2 - 4 h under the condition of aeration (DO ≥ 2.0 mg / L), and then inoculated into the second circulation tank 32. Then, the pH of the washing liquid is controlled at 7.0 - 8.0 by adding sodium bicarbonate and a small amount of inorganic salt nutrient agent is supplemented. The pig house exhaust fan is turned on, and the circulating water pump spraying system is turned on for continuous spraying for 7 - 10 d. Secondly, during the operation stage, the liquid level in the second circulation tank 32 is regularly detected (the washing liquid is not discharged externally), and an appropriate amount of clear water is supplemented to maintain the constant liquid level in the second circulation tank 32. Thirdly, the concentrations of DO, ammonia nitrogen, nitrite, and nitrate nitrogen in the second washing liquid are detected daily. Finally, the mass concentration percentage of NO3 - -N in the nitrogen in the second washing liquid is used as the judgment basis for the establishment of the nitrification process. When its proportion > 30% - 40%, the biological oxidation process of ammonia is gradually established, otherwise the above steps need to be repeated.

[0066] The second stage is the domestication and enrichment stage of nitrifying bacteria: First, all the second washing liquid in the second circulation tank 32 is emptied, and fresh tap water is added again to the same liquid level height. Secondly, the pig house exhaust fan is turned on, and the water pump in the second circulation tank 32 is turned on to start the spraying system to complete the ammonia absorption process. An appropriate amount of clear water (containing a small amount of nutrient agent) is regularly supplemented to maintain the constant liquid level in the second circulation tank 32, and the pH value gradually decreases from neutral to weakly acidic and operates continuously for 10 - 15 d. Finally, the changes in the pH, ammonia nitrogen, nitrite, and nitrate nitrogen indexes in the second washing liquid are detected daily. When under the condition of weakly acidic pH and the mass concentration proportion of NO3 - -N > 50%, it indicates that the domestication and enrichment of nitrifying bacteria are gradually stabilizing, otherwise the above steps need to be repeated. After entering the normal operation stage, the addition of the nutrient agent is stopped, and the nutrient elements of the nitrifying bacteria are provided by the regenerated washing liquid, and the ammonia absorption follows the technical parameters of the nitrifying bacteria enrichment stage.

[0067] In Figure 1 In a preferred embodiment shown, the volume of the reuse tank 65 is larger than the sum of the volumes of the first circulation tank 22 and the second circulation tank 32, and the first circulation tank 22 or the second circulation tank 32 has a preset water level; when the water level in the first circulation tank 22 or the second circulation tank 32 is lower than the preset water level, the reuse tank 65 transports the regenerated liquid to the first circulation tank 22 or the second circulation tank 32; when the water level in the first circulation tank 22 or the second circulation tank 32 reaches the preset water level, the reuse tank 65 stops transporting the regenerated liquid to the first circulation tank 22 or the second circulation tank 32. Through the above control, the full utilization of the circulating regenerated liquid is realized.

[0068] Taking a large-scale farm in Guangdong with an odor emission of 1.2 million m 3 / h as an implementation case, a portable ammonia detection instrument is used to detect the ammonia concentrations at the inlet and outlet. The average ammonia removal efficiency of the second water curtain wall 31 is 84.5 ± 2.9% (as Figure 3As shown, its pH value can be stably maintained under weakly acidic conditions (5.3 ± 0.42) (such as Figure 4 shown), the nitrogen in the washing liquid mainly exists in the form of NH4 + -N and NO3 - -N, and the mass ratio of NO3 - -N to NH4 + -N concentration is 1.2 ± 0.1. At the same time, the nitrogen removal performance of the washing liquid regeneration system during a typical cycle (such as Figure 5 shown) is detected, and the results show that the average nitrogen removal efficiency of the regeneration system for total nitrogen is 93.1 ± 5.1%.

[0069] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms, characterized in that, Comprising: A first washing component (2), connected to the odor source (1) of the breeding farm, and the first washing component (2) removes feed dust in the odor to form a first washing liquid; A second washing component (3), connected after the first washing component (2), and the second washing component (3) absorbs ammonia in the odor and transfers the ammonia to the liquid phase, and the second washing component (3) oxidizes ammonia in the liquid phase to form a second washing liquid; A first sedimentation tank (5), connected after the first washing component (2) and connected to the sewage source (4) of the breeding farm, and the first sedimentation tank (5) simultaneously receives the first washing liquid and the sewage source (4) for sedimentation and forms a first tail water; A circulation component (6), connected after the first sedimentation tank (5) and connected to the effluent of the second washing component (3), and the circulation component (6) mixes the second washing liquid and the first tail water to form a second tail water, and the circulation component (6) performs denitrification, shortcut nitrification and sludge-water separation on the second tail water to form a regenerated liquid, and the regenerated liquid is transported to the first washing component (2) and the second washing component (3) and used for washing the odor.

2. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 1, characterized in that: The first washing component (2) includes A first water curtain wall (21), arranged facing the flowing direction of the odor, and the first water curtain wall (21) washes and removes feed dust in the odor through a spraying water curtain; A first circulation tank (22), arranged below the first water curtain wall (21) and receiving the washing water falling from the first water curtain wall (21) to form a first washing liquid.

3. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 2, characterized in that: The second washing component (3) includes A second water curtain wall (31), also arranged facing the flowing direction of the odor, and the second water curtain wall (31) absorbs ammonia in the odor through a spraying water curtain; A second circulation tank (32), arranged below the second water curtain wall (31) and receiving the washing water falling from the second water curtain wall (31); A packing frame (33), arranged in the second circulation tank (32), and packing attached with nitrifying bacteria is arranged in the packing frame (33), and nitrifying bacteria oxidize ammonia in the washing water to form a second washing liquid.

4. An ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 3, characterized in that: The circulation component (6) includes An adjustment tank (61), connected after the first sedimentation tank (5), and the first tail water in the first sedimentation tank (5) flows into the adjustment tank (61) by gravity, and the second washing liquid of the second washing component (3) is diverted and injected into the adjustment tank (61); A denitrification tank (62), connected after the adjustment tank (61) and performing denitrification on the second tail water; A second sedimentation tank (63), connected after the denitrification tank (62) and performing sludge-water separation on the denitrified second tail water; A shortcut nitrification tank (64), connected after the second sedimentation tank (63) to oxidize the remaining ammonia nitrogen in the second tail water to nitrite and perform sludge-water separation again to obtain a regenerated liquid; A reuse tank (65), connected after the shortcut nitrification tank (64) and receiving the regenerated liquid, and adding clear water to the reuse tank (65).

5. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 3, characterized in that: The washing water used for the first water curtain wall (21) is sourced from the first circulation tank (22); the washing water used for the second water curtain wall (31) is sourced from the second circulation tank (32).

6. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 4, characterized in that, It further includes: An hydrolysis acidification tank (7), connected between the sewage source (4) and the first sedimentation tank (5), which decomposes macromolecular organic matters in the sewage into small molecule substances and converts the hydrolysis products into volatile fatty acids.

7. An ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 6, characterized in that: An alkaline agent is added during the mixing process of the sewage and the first washing liquid in the first sedimentation tank (5) to supplement the alkalinity of the first tail water.

8. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 4, wherein: Control the DO in the regulating pond (61) to be < 0.2 mg / L, and control the COD / NO3 - -N in the regulating pond (61) to be 2.0 - 4.

0.

9. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 3, wherein: A number of packing balls (331) are arranged in the packing frame (33). Polyurethane sponge is filled in the packing balls (331), and nitrifying bacteria are attached to the polyurethane sponge. The filling rate of the packing frame (33) is 20% - 35%, and the filling rate of the packing balls (331) is 30% - 40%.

10. The ammonia-containing odor treatment and washing liquid regeneration device for livestock and poultry farms according to claim 4, characterized in that: The volume of the reuse tank (65) is larger than the sum of the volumes of the first circulation tank (22) and the second circulation tank (32), and the first circulation tank (22) or the second circulation tank (32) has a preset water level; When the water level in the first circulation tank (22) or the second circulation tank (32) is lower than the preset water level, the reuse tank (65) transports the regenerated liquid to the first circulation tank (22) or the second circulation tank (32); When the water level in the first circulation tank (22) or the second circulation tank (32) reaches the preset water level, the reuse tank (65) stops transporting the regenerated liquid to the first circulation tank (22) or the second circulation tank (32).

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