378 results about "Aerobic denitrification" patented technology

The invention relates to an agrobacterium strain (Agrobacterium sp.) with heterotrophic nitrification-aerobic denitrification capability and an application thereof in nitrogenous effluent treatment. The bacterial strain is characterized in that: 16S rRNA gene contains nucleotide sequence shown in sequence table with a sequence length of 1418bp and a accession number FJ639330 in Genbank. The preservation number thereof is CGMCC No.2962. The agrobacterium of the invention has not only heterotrophic nitrification capability but also aerobic denitrification capability. During nitrogenous effluent treatment, and one aerobic phase can cause ammonian to change into gaseous product with high denitrification efficiency and easy operation and tremendous economic benefit compared with the traditional biological denitrification process.

The invention relates to aerobic denitrifying paracoccus denitrificans and application thereof. A bacterial strain provided in the invention is paracoccus denitrificans DN-3CGMCC No. 3658; the Paracoccus denitrificans can carry out aerobic denitrification by using nitrate nitrogen under both aerobic and oxygen-limited conditions and can also carry out heterotrophic nitrification-aerobic denitrification by using ammonia-N, and a total nitrogen removal rate on above mentioned occasions is greater than 90%. The paracoccus denitrificans provided in the invention has stable hereditary features, isapplicable to treatment of a variety of nitrogen-containing waste water and produces a good nitrogen removal effect.

The invention discloses a preparation method and an application of immobilized bacteria for improving the denitrification efficiency of a constructed wetland. 1. The preparation steps are as follows: 1) screening and culturing aerobic denitrification strains which are screened out of the constructed wetland in a thermotank; 2) selecting aerobic denitrification bacteria in slope conservation, inoculating into a sterile enrichment culture medium and aerating to get bacterial suspension; 3) using sodium alginate-polyvinyl alcohol to embed so as to get the immobilized aerobic denitrification bacteria; and 4) taking pellets of the aerobic denitrification bacteria out of a refrigerator, washing with double distilled water or physiological saline, soaking in the physiological saline, and aerating to activate the immobilized pellets. 2. An application of the immobilized bacteria in the constructed wetland is as follows: filling the immobilized pellets into a simulation column of the constructed wetland for performing waste water denitrification treatment. The preparation method of the immobilized bacteria is simple, the production cost is low, the application in the industrial waste water treatment is easy, the denitrification efficiency is high, the accumulation amount of nitrite nitrogen is low, and the service life is long.

The invention discloses a pseudomonas sp. strain capable of carrying out biological denitrification under a low temperature and an application thereof. The pseudomonas sp. strain HA11 provided by the invention was collected in the China General Microbiological Culture Collection Center (CGMCC) on September 15, 2010, with the collection number of CGMCC No.4169. At the temperature of 10-20 DEG C, the strain can carry out biological denitrification as long as the strain is put into the nitrogenous wastewater with dissolved oxygen of 2-6mg / L. The strain has the following beneficial effects: the strain has strong tolerance to low temperature, can grow well under a low temperature and simultaneously has the capabilities of heterotrophic nitrification and aerobic denitrification; and the strain can carry out nitrification and denitrification synchronously under low temperature and aerobic conditions to efficiently and thoroughly remove the total nitrogen in the sewage, thus effectively solving the great difficulty in carrying out biological denitrification under a low temperature and having a good application prospect.

The invention relates to a high salt-tolerant bacillus alitudinis with functions of heterotrophic nitrification-aerobic denitrification and phosphorous removal and application thereof to wastewater treatment. The bacillus alitudinis has strong high salt environment tolerance, grows well under a high-salt condition, and can metabolize by taking organic carbon as one and only carbon source and ammonia nitrogen as one and only nitrogen source; through the heterotrophic nitrification-aerobic denitrification, the ammonia nitrogen is directly converted into a gaseous product so as to achieve a denitrifying purpose; the bacillus alitudinis can also take nitrate nitrogen as one and only nitrogen source, the nitrate nitrogen is converted into a gaseous product through the aerobic denitrification; and under aerobic conditions inorganic phosphorus can be taken into a body and converted into a component of the body so as to realize a purpose of removing phosphorus in sewage. The bacillus alitudinis is applied to high-salt wastewater treatment, can achieve synchronization removal of nitrogen and phosphorus under a single aerobic condition, and provides a new way for solving a problem of biological removal of the nitrogen and phosphorus under the high-salt condition.

A process for treating nitrogenous wastewater contains an autotrophic denitrification reaction, a heterotrophic denitrification reaction and a COD removal reaction simultaneously and mixedly taking place in a single reactor. The nitrification reaction is caused by nitrifying bacteria, in which ammonium is oxidized into nitrite. The autotrophic denitrification reaction is caused by autotrophic denitrifying bacteria, in which ammonium used as electron donor and nitrite used as electron acceptor are converted into nitrogen gas and nitrate. The heterotrophic denitrification reaction is caused by heterotrophic denitrifying bacteria, in which nitrate and COD are consumed. It is not necessary to build two separate reactors for aerobic nitrification and anaerobic denitrification, thereby effectively reducing the fabrication and operation cost.

The invention relates to a reduction method for biological sludge, which comprise the following steps: adding a Tween surfactant into the sludge for carrying out cell wall breaking on the remaining sludge, wherein the added amount of the surfactant is 10 to 500 mg / l; and adding alkali and adjusting the pH value to be between 9 and 13, the temperature to be between 10 and 100 DEG C and the processing time to be between 15 and 300 minutes. The method improves the wall breaking effect and reduces the wall breaking cost, and greatly reduces the cell dissolving cost of the sludge with small investment. By returning the biological sludge subjected to cell dissolving to an anaerobic or anoxic tank for carrying out anaerobic-anoxic-aerobic denitrification and phosphorous removal processes, the method not only can reduce the sludge production, but also provide carbon sources for denitrification and phosphorous removal, thereby improving the denitrification and phosphorous removal efficiency.

The invention discloses an achromobacter xylosoxidans strain for biological denitrificaion and application thereof. The achromobacter xylosoxidans strain GAD3 is preserved in China General Microbiological Culture Collection Center (CGMCC for short) with preservation number CGMCC No. 2964 in March 19th, 2009. The strain is added to nitrogenous effluent with 2 to 6mg / L of dissolved oxygen to realize biological denitrificaion. The strain not only has the capability of heterotrophic nitrification, but also has the capability of aerobic denitrification. In the process of treating the nitrogenous effluent, only one aerobic stage is needed, the denitrification efficiency is high, and the operation is convenient and quick; and compared with the conventional biological denitrification process, the application has huge economic benefits.

The invention discloses achromobacter xylosoxidans subsp.xylosoxidans LH-N25 with CGMCC No.6972. The invention also discloses a heterotrophic nitrification and aerobic denitrification microorganism bactericide. The microorganism bactericide comprises achromobacter xylosoxidans subsp.xylosoxidans LH-N25 or also comprises paracoccus aminovorans LH-N40; and the strains are combined according to any ratio. The invention also discloses a preparation method of the microorganism bactericide. The microorganism bactericide disclosed by the invention not only can solve the problem that total nitrogen cannot be easily removed in the traditional reactor, but also can effectively remove ammonia nitrogen and total nitrogen in a water body in the same reactor, and has tolerance and degradation ability on the toxic substances such as phenols, amines, hetercyclics, cyanogens and polyaromatic hydrocarbon in the wastewater at the same time. The microorganism bactericide is especially suitable for chemical wastewater containing nitrogen, is simple in treatment process, stable in effect, and resistant to impact of environmental toxic substances, and has a wide application prospect in treatment of chemical wastewater containing nitrogen.

The invention provides a device and a method for treatment of low-temperature and low-carbon ammonia nitrogen wastewater on the basis of solid-phase denitrification and heterotrophic nitrification-aerobic denitrification. The device comprises a reactor and a reflux system, wherein the upper part and lower part of the reactor are respectively provided with a fluidized bed aerobic zone and a filterpool anoxic zone which are filled with a solid carbon source filling material and separated by a porous water distribution plate; an aeration tube is arranged on the water distribution plate and connected with an aeration device through a gas flowmeter; the lower end of the reactor is provided with a water inlet; the upper end of the reactor is provided with a water outlet; an effluent of the reactor enters a secondary sedimentation tank, and an effluent of the secondary sedimentation tank enters an intermediate water storage tank through an overflowing opening; the upstream end of the refluxsystem communicates with an effluent of the intermediate water storage tank; the downstream end of the reflux system communicates with the reflux opening of the lower end of the reactor through a liquid flowmeter; and the interior of the fluidized bed aerobic zone is provided with a dissolved oxygen monitor and a nitrate concentration monitor. The device and the method provided by the invention can still realize highly-efficient removal of ammonia nitrogen and total nitrogen under the conditions of low temperature and low carbon.

The invention breaks through the restriction of the traditional autotrophic nitrification and anoxic denitrifying metabolism principle, and discloses a method for removing carbon and nitrogen pollutants in waste water in one step according to physiological feature and metabolism principle of heterotrophic nitrification-aerobic denitrification bacteria. In a single biochemical reactor, mixed solution of the heterotrophic nitrification-aerobic denitrification bacteria and active slurry in a certain proportion is inoculated, after a certain period of aeration is performed, nitrogen and organic substances are removed at the same time, and the efficiency of denitrification and carbon removal is high. By using the method, a traditional biochemical treatment system can be updated and transformedwithout constructing a new building based on the traditional biochemical treatment system, and the operation is convenient and fast. The method overcomes the bottleneck problems that the nitrobacteria propagate slowly, the nitrification and denitrification reactions are performed in sections, and the like.

The invention belongs to the technical field of microorganism denitrification, and particularly discloses a pseudomonas mendocina MKC-02 strain and the application of the pseudomonas mendocina MKC-02 strain to waste water denitrification. The strain is preserved in the Guangdong Microbial Culture Collection Center (GDMCC) in November 14, 2016, and the preservation number is GDMCC No:60104. The strain is a heterotrophic nitrification-aerobic denitrification strain, simultaneous nitrification and denitrification is possible, and the strain has great application value in the sewage treatment aspect.

The invention relates to denitrification acinetobacters and a use thereof, and belongs to the field of environmental microbiology. The denitrification acinetobacters have a category name of Acinetobacter schindleri LN5, are preserved in the China general microbiological culture collection center of the China microbiological preservation management committee on May 30th, 2012, and has a preservation number of CGMCC No.6165. The denitrification acinetobacters have heterotrophic nitrification-aerobic denitrification functions, have high aureomycin resistance, can be used for simultaneous nitrification and denitrification (SND) treatment on nitrogen-containing sewage and especially on nitrogen and aureomycin-containing sewage, realize removal of a large part of ammonia nitrogen in nitrogen-containing sewage, realize small accumulation amounts of nitrite and nitrate nitrogen, realize nitrification-denitrification and COD removal in the same reactor, and realize environmentally-friendly, low-consumption and high-efficiency treatment on nitrogen-containing sewage.

The invention discloses a salinivibrio strain which can carry out biological denitrification under high-saline conditions, and an application thereof. The salinivibrio strain provided by the invention is collected in China General Microbiological Culture Collection Center (CGMCC) on 29th March, 2012 with a collection number of CGMCC No.5946. With a salinity (calculated according to NaCl) below 3-10%, the strain is placed in nitrogen-containing wastewater with dissolved oxygen of 2-6mg / L, such that biological denitrification can be carried out. The strain has high tolerance to high salinity, and grows well in a high-saline condition. The strain has both heterotrophic nitrification and aerobic denitrification capacities. Under a high-saline aerobic condition, the strain can carry out synchronous nitrification and denitrification, such that total nitrogen in sewage can be completely removed with high efficiency. Therefore, a major problem of biological denitrification under high-saline conditions is effectively solved, and a good application prospect is provided.

The invention discloses heterotrophic nitrification-aerobic denitrification pseudomonas mendocina as well as culture and application thereof. The strain is pseudomonas mendocina WZUF22 and is collected at the China General Microbiological Culture Collection Center with a registration number CGMCC No. 7523. The strain WZUF22 has proper pH (potential of Hydrogen) and wide temperature range during heterotrophic nitrification and aerobic denitrification, has high removal rate for NH4<+>-N, NO3<->-N and NO2<->-N and can provide a source for synchronous nitrification and denitrification.

The invention relates to a heterotrophic nitrification-aerobic denitrification compound bacterial agent for low-temperature high ammonia-nitrogen removal and application. The compound bacterial agentis formed by compounding of 10-20% of cupriavidus SWA1, 5-20% of alcaligenes faecalis, 10-30% of acinetobacter and 20-50% of ochrobacterum TAC-2. The compound bacterial agent has advantages of high ammonia-nitrogen resistance, low-temperature resistance, heavy metal resistance and synchronous nitrification and denitrification; by synergistic effects of four microorganisms, efficient denitrification of high ammonia-nitrogen wastewater can be realized in an aerobic environment under low-temperature conditions.

The invention discloses a bacillus cereus with heterotrophic nitrification-aerobic denitrification performance and an N2O emission control method thereof, wherein the accession number of the bacilluscereus is CGMCC NO.3047. The bacillus cereus can degrade nitrate under the aerobic condition and perform denitrification; and the bacillus cereus can also grow in the ammonia nitrogen wastewater, perform heterotrophic nitrification-aerobic denitrification by using ammonia nitrogen under the aerobic condition, obtain the gaseous product N2O with extremely low emission amount in the denitrificationprocess and achieve the purpose of N2O emission control from the biological point of view.

The invention discloses a comamonas testosteroni strain for biological denitrificaion and application thereof. The comamonas testosteroni strain GAD4 is preserved in China General Microbiological Culture Collection Center (CGMCC for short) with preservation number CGMCC No. 2963 in March 19th, 2009. The strain is added to nitrogenous effluent with 2 to 6mg / L of dissolved oxygen to realize biological denitrificaion. The strain not only has the capability of heterotrophic nitrification, but also has the capability of aerobic denitrification. In the process of treating the nitrogenous effluent, only one aerobic stage is needed, the denitrification efficiency is high, and the operation is convenient and quick; and compared with the conventional biological denitrification process, the application has huge economic benefits.

The invention discloses a pseudomonas stutzeri and application thereof. The name of pseudomonas stutzeri is pseudomonas stutzeri XL-2 and is preserved in China General Microbiological Culture Collection Center (CGMCC for short) on November 10, 2016; the preservation number is No. 13252. The strain is obtained by taking active sludge of Chongqing Jiguanshi Sewage Treatment Plant as the raw material and carrying out repeated domestication separation by using a high-concentration nitrate nitrogen NO3-N selective culture medium. The pseudomonas stutzeri is capable of carrying out aerobic denitrification by using high-concentration NO3-N under aerobic condition; after the pseudomonas stutzeri is cultured for 20 hours, the removal rate of NO3-N of the pseudomonas stutzeri reaches up to 95.5%; the removal rate of total nitrogen (TN) can reach 84.8%; the final removal rate of COD reaches 74.5%; and the accumulation of an intermediate product, namely nitrite nitrogen (NO2-N), is avoided. In addition, the pseudomonas stutzeri has the effect of automatically gathering and settling; rod-shaped cells are embedded with each other and are gathered at the bottom of the culture medium in bulks; sludge-water separation can be rapidly achieved; the pseudomonas stutzeri has a good application prospect in the field of treatment of high-concentration nitrogen-containing wastewater.

The invention belongs to the field of microbe, and particularly relates to a halomonas campisalis with heterotrophic nitrification aerobic denitrification function and an application thereof. The preservation number of the halomonas campisalis BMEN3 (Halomonas campisalis. BMEN3) with heterotrophic nitrification aerobic denitrification function is CGMCC NO.6536. According to the halomonas campisalis BMEN3, the 16S rDNA sequence of the halomonas campisalis is shown as SEQ IDNo.1. The selected bacterial strain Halomonas campisalis. BMEN3 has heterotrophic nitrification and aerobic denitrification ability under the condition of high salinity and high alkali, and the bacterial strain can grow under the condition of aerobic heterotrophism, so that the growth velocity of the thallus is greatly improved, the biofilm culturing speed is enhanced, the starting time of the reactor is shortened, and the denitration efficiency is improved. The salinity and pH that the bacterial strain can adapt are wide in range, and the extreme value is high.

The invention discloses an ammonia nitrogen-removed compound microorganism microbial agent. The ammonia nitrogen-removed compound microorganism microbial agent is prepared from Providencia rettgeri, Microbacterium lactium, Lactobacillus delbrueckii and Rhodococcus coprophilus in a volume ratio of 5 to 2.5 to 1 to 5. The invention further discloses application of the compound microorganism microbial agent in ammonia nitrogen-containing wastewater treatment. The four bacteria are reasonably matched and are combined by virtue of an adsorption method and an embedding method to form immobilized cell particles, so that the ammonia-nitrogen degradation capacity and stability of the compound microorganism microbial agent are remarkably enhanced; a dominant bacterial community can be immediately formed after the compound microorganism microbial agent is applied to denitrification and treatment process of sewage, river way landscape water and the like, the treatment time is short, and ammonia and nitrogen indexes of the sewage are rapidly decreased; and meanwhile, the compound microorganism microbial agent has an aerobic denitrification function and further has relatively good effect of removing COD, and accumulation of nitrite and nitrate is avoided.

The invention belongs to the field of environmental microorganisms and discloses a high-temperature-resistant aerobic denitrification bacteria, of which the classification name is pseudomonas stutzeri sp., wherein the strain has been preserved at China center for type culture collection at 2015 Jan.9 and has been assigned the accession number CCTCC NO: M2015027. The invention also discloses an application of the high-temperature-resistant aerobic denitrification bacteria. The strain grows well at 50 DEG C, has strong denitrification performance, is very less in accumulation of nitrite during denitrification and is free of secondary pollution. In the invention, the high-efficient aerobic denitrification bacteria are obtained through screening from a eutrophic lake water body, when being subjected to enlarged cultivation, the bacteria strain can be directly used for denitrification on lake water and can avoid environmental inadaptability of non-indigenous microorganisms. The bacteria strain can achieve huge economic benefit when being used in treatment of industrial waste.

The invention discloses a microbial degradation method for pollutants in industrial sewage. The method includes: (1) taking chemical plant industrial sewage, and testing the initial ammonia nitrogen concentration; (2) adding a compound microbial agent into industrial sewage, then adding a certain amount of carbon source, and then performing microbial cultivation; (3) adding diatomite into the chemical plant industrial sewage, conducting stirring and pumping filtration to obtain supernatant; (4) adding the compound microbial agent and the carbon source into the supernatant again, and performing cultivation; and (5) subjecting the supernatant to centrifugal treatment to obtain supernate, i.e. restored industrial sewage. According to the invention, a screened efficient heterotrophic nitrification-aerobic denitrification strain, i.e. a compound inoculant of raoultella and pseudomonas is adopted as the bacteria source for inoculation and expanding culture, and is then applied to purification treatment of high pollution industrial sewage, mainly for lowering the ammonia nitrogen concentration exceeding the standard. Use of the compound inoculant for treatment of industrial sewage has the advantages of simple operation, high efficiency and good treatment effect, etc.

The invention provides a heterotrophic nitrification-aerobic denitrification bacterium and application thereof and belongs to the technical field of microorganisms. The bacterium is alteromonas macleodii SLNX2 and is preserved in China General Microbiological Culture Collection Center (CGMCC) on November 27, 2015; and the preservation number is CGMCC NO. 11757. The invention further provides a method for purifying culture wastewater by utilizing the bacterium. The method specifically comprises the following step: controlling an adding final concentration of three heterotrophic nitrification-aerobic denitrification bacteria in a fish culture water body to be 1.3*10<6>CFU.mL<-1>. According to the method provided by the invention, the compound application and purification effect of the three bacteria is better than that of the single bacterium, so that ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen and chemical oxygen demand in the water body are lower than that of a control group without the bacterium and are lower than 68.55%, 48.36%, 58.38%, 40.02% and 27.47% respectively at maximum.

The invention discloses a three-dimensional floating bed and sinking bed combined type river water purifying device which comprises a reinforced ecological floating bed system and an ecological sinking bed system. The ecological floating bed system comprises emergent aquatic plants, filler and clams, wherein a biological film formed by a heterotrophic nitrification and aerobic denitrification bacterium hanging film is cultivated on the filler. The ecological sinking bed system comprises submerged plants, filler and ceramic particles, wherein a biological film formed by a humic acid reduction bacterium hanging film is arranged on the filler. The removal rate of COD in a water body can reach 60-80%, the nitrogen removal rate can reach 50-60%, the phosphorus removal rate can reach 20-30%, and the removal rate of humic acid and other large molecules difficult to degrade reaches 50-60%; by means of a float, the device can float up and sink down in water; due to the three-dimensional type structure and the adjustable structure, the water purification of a deep river bed is facilitated; in winter, ceramic particles can continuously have an adsorption effect so that water can be purified. A continuous effect is achieved for the water body of a river way, the ecological system of the river way is improved, and the self-purification capacity of the water body is restored.

The invention belongs to the field of microorganisms, and discloses a strain of pseudomonas stutzeri ZH-14 with an aerobic denitrification function. The preservation number of the pseudomonas stutzeriZH-14 is CCTCC NO:M2018730. The pseudomonas stutzeri can be applied to degrading ammonia nitrogen or nitrate nitrogen or nitrite nitrogen or COD in nitrogen-containing sewage. The pseudomonas stutzeri ZH-14 has the advantages that the pseudomonas stutzeri ZH-14 has the aerobic denitrification function and a heterotrophic nitrification function, and the accumulation of the nitrite nitrogen with the extremely low content is involved in the degradation process; nitrite can be directly utilized for growth metabolism, the activity of nitrate reductase of the pseudomonas stutzeri ZH-14 is still high in an environment with a low carbon-nitrogen ratio, the aerobic expression is less influenced by the types of adopted carbon sources, and the carbon source problem in the process of utilizing aerobic denitrification bacteria for treating nitrogen-containing wastewater is solved.

The invention provides a low energy consumption integrated hydrolysis-denitrifying ammoxidation process for treating low C / N ratio wastewater, and belongs to the technical field of wastewater treatment in environment engineering. The process is characterized in that: a second hydrolysis region and an aerobic denitrification region are connected in series to provided a nitrate nitrogen electron acceptor for the denitrifying ammoxidation process; the second hydrolysis region is connected in parallel to provide volatile fatty acid and ammonia nitrogen; and autotrophic nitrogen removal without an additional carbon source can be realized in the denitrifying ammoxidation reacting region finally. The process has the advantages of improving the nitrogen pollutant removal effect without the additional carbon source, reducing aeration energy consumption and sludge yield, and reducing greenhouse gas emission compared with the traditional denitrification process; and the design of a modular reactor guided by an integrated baffle and the flow design without sludge return can effectively reduce floor area, and greatly reduce operation complexity.

The invention discloses a small brevibacterium strain capable of carrying out biological denitrification under the high-salt condition and application of the small brevibacterium strain. The small brevibacterium strain provided by the invention is preserved in China General Microbiological Culture Collection Center (CGMCC for short) on March 29th, 2012, with the preservation number of CGMCC No.5947. At the salinity (counted by NaCl) is 3-10 percent, the strain is added into nitrogen-containing wastewater with dissolved oxygen of 2-6mg / L for biological denitrification. The strain has strong resistant ability for high salinity and heterotrophic nitrification and aerobic denitrification capabilities and can better grow under the high-salinity condition. Under the high-salinity and aerobic conditions, the strain can be used for synchronous nitrification and denitrification and efficiently and thoroughly removing total nitrogen in sewage, and thus the major problem that biological denitrification is difficult to carry out under the high-salinity condition is effectively solved and a favorable application prospect is obtained.

The invention discloses a polyculture enrichment screening method for ocean heterotrophic denitrifying bacteria. With the method, the ocean heterotrophic denitrifying bacteria can be enriched in an early-stage autotrophic mode and a later-stage heterotrophic mode, and the bacteria with heterotrophic nitrification capability and heterotrophic nitrification and aerobic denitrification capability can be guaranteed to propagate. The polyculture enrichment screening method comprises the following steps: firstly, separating a selective culture medium; then, detecting and separating the ammonia monooxygenase gene and the nitrite oxidoreductase gene of a bacterial strain; finally, in a heterotrophic culture medium, determining whether a bacterial strain with a target gene is expressed or not by a nitrogen balance test. The autotrophic mode and the heterotrophic mode are alternately used for domestication and, enrichment as well as separation to finally obtain the screened bacterial strain which is determined as the heterotrophic nitrification bacterial strain or the heterotrophic nitrification and aerobic denitrification bacterial strain. The polyculture enrichment of heterotrophic nitrification and aerobic denitrification bacteria is not only the breakthrough of the bacteria enrichment theory, the bacterial strain is immobilized with a biofortification method to have a great practical application meaning for the biological denitrification of ocean cycling breeding wastewater, and the method is suitable for treating wastewater in the nitrification unit for the factory high-density breeding.