PBR biological pretreatment method and denitrification method for high-concentration cyanide wastewater

Abstract

The invention relates to the technical field of wastewater biological treatment, and discloses a PBR biological pretreatment method and a denitrification method for high-concentration cyanide wastewater. The biological pretreatment method comprises the following steps: (1) detecting the concentration of total cyanide in the cyanide wastewater, when the detected concentration of the total cyanide is higher than 1300mg / L, performing water quality regulation until the concentration of the total cyanide is not higher than 1300mg / L, and then performing a step (2); and (2) introducing the cyanide wastewater into a biological pretreatment device inoculated with the minicalatomonas 324B6, and carrying out ammoniation to remove cyanide so as to obtain the pretreated wastewater, wherein the minicalatomonas 324B6 is inoculated with the minicalatomonas 324B6. In the biological pretreatment and denitrification method disclosed by the invention, the micromonas 324B6 is adopted to treat the cyanide wastewater, so that efficient ammonification and removal of cyanide can be realized, and the problem that the cyanide wastewater is difficult to efficiently treat through a microbiological method due to over-high biotoxicity is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of biological wastewater treatment, and particularly relates to a biological pretreatment method and a denitrification method for high-concentration cyanide wastewater. Background Art

[0002] With the development of industries such as mining, electroplating, and coking, wastewater containing cyanide (chemical formula -C≡N or -CN) is continuously generated, and the discharge amount is increasing day by day. Cyanide wastewater is characterized by high toxicity and strong pollution. Most cyanides are highly toxic and act quickly, with a very low lethal dose in organisms. After being discharged into the environment, it can cause ecological imbalance, death of livestock, and reduction of crop yields, and also pose a threat to human health. Therefore, the harmless treatment of cyanide wastewater is of great importance.

[0003] Compared with physical and chemical methods, the microbial method uses the metabolic activities of cyanide-degrading bacteria to remove cyanide in wastewater, and has the advantages of simple process, low operating cost, no secondary pollution, etc., and thus has a good development prospect. However, due to the strong biological toxicity of cyanide and the poor biodegradability of cyanide wastewater, the existing cyanide-degrading bacteria can tolerate and effectively treat relatively low cyanide concentrations. When used for the treatment of high-concentration cyanide wastewater (cyanide concentration higher than 500 mg / L), it is necessary to dilute it with a large amount of water in advance, or reduce the cyanide concentration by physical and chemical methods, resulting in low wastewater treatment efficiency and high treatment cost. Summary of the Invention

[0004] In order to solve the above technical problems, that is, the biological toxicity of high-concentration cyanide wastewater is too high and it is difficult to achieve efficient treatment by the microbial method, the present invention provides a PBR biological pretreatment method and a denitrification method for high-concentration cyanide wastewater. In the biological pretreatment and denitrification methods of the present invention, Microcystis minima 324B6 is used to treat cyanide wastewater, which can achieve efficient ammoniation and removal of cyanide, and overcomes the problem that it is difficult to efficiently treat cyanide wastewater with high biological toxicity by the microbial method.

[0005] The specific technical solution of the present invention is as follows: In the first aspect, the present invention provides a PBR biological pretreatment method for high-concentration cyanide wastewater, including the following steps: (1) Detect the total cyanide concentration in the cyanide wastewater. When the measured total cyanide concentration is higher than 1300 mg / L, adjust the water quality until the total cyanide concentration is not higher than 1300 mg / L, and then proceed to step (2); (2) The cyanide wastewater is introduced into a pioneer bioreactor inoculated with Pusillimonas sp. 324B6 for ammonification to remove cyanide and obtain pretreated wastewater; the Pusillimonas sp. 324B6 was deposited at the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on November 8, 2023, with the deposit number CGMCC No. 28905.

[0006] The strain Pusillimonas sp. 324B6 used in the present invention belongs to a new species within the genus Pusillimonas. The 16S rDNA sequence and physiological and biochemical characteristics are shown in Example 1. In the present invention, this new species is temporarily referred to as "Pusillimonas sp.".

[0007] Pusillimonas sp. 324B6 has a high tolerance to the toxicity of cyanide and can achieve efficient ammonification (converting N in -CN to NH3-N) and removal of cyanide. Compared with cyanide, the NH3-N generated after treatment with Pusillimonas sp. 324B6 has lower biological toxicity and can be removed by conventional biological treatment methods (a large number of biological treatment methods for removing NH3-N from wastewater have been reported).

[0008] In addition, in addition to cyanide, Pusillimonas sp. 324B6 can also effectively degrade methanol, ethanol, tetrahydrofuran (THF), dichloromethane, N,N-dimethylformamide (DMF), and triethylamine. Therefore, while ammonifying and removing cyanide in the wastewater, it can also achieve good treatment effects on the above-mentioned common organic pollutants in the cyanide wastewater.

[0009] A pioneer bioreactor (PBR) is a wastewater pretreatment device that uses a microbial fermentation process to decompose and utilize refractory organic matter, thereby improving the biodegradability of high-concentration wastewater. In the present invention, a PBR inoculated with Pusillimonas sp. 324B6 is used, which can ammonify and remove cyanide in the wastewater, improve the biodegradability of the cyanide wastewater, and at the same time reduce the contents of methanol, ethanol, THF, dichloromethane, DMF, and triethylamine in the wastewater.

[0010] Preferably, before step (2), the COD value of the wastewater is adjusted to not higher than 40000 mg / L, the TN value is not higher than 2000 mg / L, the NH3-N concentration is not higher than 2000 mg / L, the TDS value is not higher than 2%, and the pH is 7.5 - 8.0.

[0011] Preferably, in step (2), in the pioneer bioreactor, the dissolved oxygen content is controlled to be not lower than 2 mg / L, and the water temperature is 25 - 30 °C.

[0012] Preferably, in step (2), during the biological pretreatment, KH2PO4 is added to the pioneer bioreactor at a dosage of 0.1 g / L.

[0013] Second, the present invention provides a method for denitrifying high-concentration cyanide wastewater, comprising the following steps: (I) Using the above biological pretreatment method to perform biological pretreatment on cyanide wastewater to obtain pretreated wastewater; (II) Passing the pretreated wastewater into a nitrification device inoculated with nitrifying bacteria for nitrification treatment to obtain nitrified wastewater; (III) Passing the nitrified wastewater into a denitrification device inoculated with denitrifying bacteria for denitrification treatment to obtain denitrified wastewater.

[0014] After the cyanide wastewater is treated by Microcystis aeruginosa 324B6, the cyanide therein is converted into NH3-N, which can be converted into NO2 through nitrification treatment - -N and / or NO3 - -N, and then further converted into nitrogen through denitrification treatment, realizing the denitrification of cyanide wastewater.

[0015] Preferably, in step (III), the denitrifying bacteria is Paracoccus denitrificans 392A9, which was deposited in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on October 20, 2023, with the deposit number CGMCC No. 28691.

[0016] Paracoccus denitrificans 392A9 can tolerate and effectively treat nitrate (NO3 - -N) concentrations up to 10,000 mg / L. Currently, within the species Paracoccus denitrificans, no strains have been reported to have the ability to tolerate and treat high-concentration nitrates at a level comparable to that of the strain of the present invention.

[0017] Moreover, the aerobic denitrification process and the anaerobic denitrification process each have their own advantages and disadvantages (the aerobic process requires oxygen supply and consumes more electricity, that is, more electricity costs, but it is relatively safe; the anaerobic process does not require oxygen, only stirring, and consumes less electricity, but there are safety risks). However, Paracoccus denitrificans 392A9 can perform efficient denitrification on wastewater with high nitrate concentrations under both aerobic and anaerobic conditions. Therefore, the anaerobic and aerobic processes can be flexibly selected according to different requirements.

[0018] In addition, Paracoccus denitrificans 392A9 can adapt to a relatively wide pH range. Through experiments, it is found that under aerobic and anaerobic conditions, this strain can survive and remove nitrates in wastewater in an environment with a pH of 5.0 - 9.0. Therefore, when this strain is used for the denitrification treatment of wastewater, it can simplify the process of adjusting the pH of the wastewater in the early stage, reduce the use of pH adjustment reagents, and lower the cost of wastewater treatment.

[0019] Furthermore, in step (III), in the denitrification device, the dissolved oxygen content is controlled to be no higher than 0.5 mg / L, and the water temperature is 25 - 30 °C.

[0020] Preferably, before step (II), the pretreated wastewater is subjected to flocculation air flotation to remove the bacteria in it.

[0021] Preferably, after step (III), the denitrified wastewater is subjected to flocculation air flotation to remove the bacteria in it.

[0022] Furthermore, after the denitrified wastewater is subjected to flocculation air flotation, a part of the wastewater is refluxed to the pioneer bioreactor, and the reflux ratio is 100 - 200%.

[0023] During the anaerobic denitrification process, the organic nitrogen in the wastewater can be further ammoniated to NH3-N. By refluxing the wastewater after denitrification and through air flotation and flocculation to the pioneer bioreactor, this part of NH3-N can be further removed.

[0024] Compared with the prior art, the present invention has the following advantages: (1) The Pusillimonas sp. 324B6 used in the present invention belongs to a new species within the genus Pusillimonas. Using this strain for the biological pretreatment of cyanide-containing wastewater can achieve the efficient ammoniation and removal of cyanide, overcoming the problem that it is difficult to efficiently treat cyanide-containing wastewater by the microbial method due to its high biological toxicity.

[0025] (2) After the present invention uses Pusillimonas sp. 324B6 for the biological pretreatment of cyanide-containing wastewater and then sequentially performs nitrification and denitrification treatments, the denitrification of cyanide-containing wastewater can be achieved.

[0026] (3) The Paracoccus denitrificans 392A9 used in the denitrification treatment of the present invention can tolerate and effectively treat high-concentration (up to 10,000 mg / L) nitrates under both aerobic and anaerobic conditions, and can adapt to a relatively wide pH range, and can survive and remove nitrates in wastewater in an environment with a pH of 5.0 - 9.0. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow diagram for the denitrification treatment of wastewater in Example 6.

[0028] Figure 2 Schematic diagram of the small-scale PBR biological treatment test device used in Example 2.

[0029] Figure 3 Treatment effect of strain 324B6 on TN and organic nitrogen ammonification of wastewater. Among them, "NH3-N of PBR-1" and "TN of PBR-1" respectively refer to NH3-N and TN in the effluent of PBR-1 pool, and "NH3-N of PBR-2" and "TN of PBR-2" respectively refer to NH3-N and TN in the effluent of PBR-2 pool.

[0030] Figure 4 Treatment effect of strain 324B6 on TOC of wastewater. Among them, "PBR-1" and "PBR-2" respectively refer to the effluent of PBR-1 pool and the effluent of PBR-2 pool.

[0031] Figure 5 Microscopic examination status of strain 324B6 in the PBR pool during the stable operation period (magnification: 400 times).

[0032] Figure 6 Treatment effect of strain 324B6 on COD of wastewater. Among them, "PBR-1" and "PBR-2" respectively refer to the effluent of PBR-1 pool and the effluent of PBR-2 pool.

[0033] Figure 7 Treatment effect of strain 324B6 on TN and organic nitrogen ammonification of wastewater. Among them, "NH3-N of PBR-1" and "TN of PBR-1" respectively refer to NH3-N and TN in the effluent of PBR-1 pool, and "NH3-N of PBR-2" and "TN of PBR-2" respectively refer to NH3-N and TN in the effluent of PBR-2 pool.

[0034] Figure 8 Schematic diagram of the aerobic continuous influent and effluent test device used in Example 4.

[0035] Figure 9 Effect of influent pH on aerobic denitrification effect of strain 392A9.

[0036] Figure 10 Effect of HRT on aerobic denitrification effect of strain 392A9.

[0037] Figure 11 Schematic diagram of the anaerobic continuous influent and effluent test device used in Example 5.

[0038] Figure 12 Effect of influent pH on anaerobic denitrification effect of strain 392A9.

[0039] Figure 13Effect of HRT on anaerobic denitrification of strain 392A9 Detailed implementation manners

[0040] The present invention will be further described below in conjunction with embodiments.

[0041] General embodiment A PBR biological pretreatment method for high-concentration cyanide wastewater, comprising the following steps: (1) Detect the total cyanide concentration in the cyanide wastewater. When the measured total cyanide concentration is higher than 1300 mg / L, adjust the water quality so that the total cyanide concentration is not higher than 1300 mg / L and then proceed to step (2); (2) Feed the cyanide wastewater into a pioneer bioreactor inoculated with Pusillimonas sp. 324B6 to perform ammoniation to remove cyanide and obtain pretreated wastewater; the Pusillimonas sp. 324B6 was deposited at the General Microbiology Center of the China National Culture Collection Center on November 8, 2023, with the deposit number CGMCC No. 28905.

[0042] As a specific implementation manner, before step (2), adjust the COD value of the wastewater to not higher than 40000 mg / L, the TN value to not higher than 2000 mg / L, the NH3-N concentration to not higher than 2000 mg / L, the TDS value to not higher than 2%, and the pH to 7.5 - 8.0.

[0043] As a specific implementation manner, in step (2), in the pioneer bioreactor, control the dissolved oxygen content to not be lower than 2 mg / L, and the water temperature to be 25 - 30 °C; during the biological pretreatment, add KH2PO4 to the pioneer bioreactor, and the dosage is 0.1 g / L.

[0044] A denitrification method for high-concentration cyanide wastewater, comprising the following steps: (I) Adopt the above biological pretreatment method to perform biological pretreatment on the cyanide wastewater to obtain pretreated wastewater; (II) Feed the pretreated wastewater into a nitrification device inoculated with nitrifying bacteria to perform nitrification treatment to obtain nitrified wastewater; (III) Feed the nitrified wastewater into a denitrification device inoculated with denitrifying bacteria to perform denitrification treatment to obtain denitrified wastewater.

[0045] As a specific embodiment, in step (III), the denitrifying bacterium is Paracoccus denitrificans 392A9, which was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on October 20, 2023. The address of the depositary institution is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28691.

[0046] As a specific embodiment, in step (III), in the denitrification device, the dissolved oxygen content is controlled to be no higher than 0.5 mg / L, and the water temperature is 25 - 30 °C.

[0047] As a specific embodiment, before step (II), the pretreated wastewater is subjected to flocculation air flotation to remove the bacteria therein.

[0048] As a specific embodiment, after step (III), the denitrified wastewater is subjected to flocculation air flotation to remove the bacteria therein, and then part of the wastewater is refluxed to the pioneer bioreactor, and the reflux ratio is 100 - 200%.

[0049] The following examples are intended to further introduce and demonstrate the objectives, technical solutions, and technical effects of the present invention. Therefore, the examples should be understood as only being used to more specifically demonstrate the present invention, and not limiting the content of the present invention in any way. The raw materials used in the examples can be obtained from conventional commercial channels without special instructions, and the methods used, without special instructions, are conventional methods in the art.

[0050] In the following examples, the strain 324B6 refers to Pusillimonas sp. 324B6 with the deposit number of CGMCC No. 28905, and the strain 392A9 refers to Paracoccus denitrificans 392A9 with the deposit number of CGMCC No. 28691.

[0051] Example 1: Development of Strain 324B6 1.1 Wastewater Sample The wastewater is the high-concentration cyanide wastewater from a pharmaceutical company in Zhejiang. The main components are cyanoacetic acid, ethanol, sodium carbonate, sodium formate, ammonium bicarbonate, a small amount of sodium acetate, ammonium acetate, sodium cyanide, and cyclohexanone. The water quality is shown in Table 1.

[0052] Table 1 Wastewater Quality 1.2 Wastewater dilution Since the TDS of the wastewater is extremely high, it is diluted to about 4% TDS, that is, diluted by 5 times (i.e., wastewater: fresh water = 1:4, volume ratio). The basic water quality of the diluted wastewater is shown in Table 2.

[0053] Table 2 Basic water quality of cyanide wastewater diluted by 5 times Index Unit Value COD mg / L 17372 TOC mg / L 7695 <![CDATA[NH3-N]]> mg / L 24 TP mg / L 0.04 <![CDATA[NO2 - -N]]> mg / L 0 <![CDATA[NO3 - -N]]> mg / L 0 TN mg / L 1700 TDS ％ 3.60 pH / 10 1.3 Nutrient adjustment of wastewater The diluted wastewater is subjected to nutrient adjustment, and the specific method is as follows: Add KH2PO4 0.5 g / L to the diluted wastewater and adjust the pH to 7.5 - 8.0.

[0054] 1.4 Source of strains The strains are sourced from the high-salt pharmaceutical and chemical PBR system strain library (containing more than 1000 strains) accumulated by the research team of this invention through long-term scientific research.

[0055] 1.5 Culture medium The formula and preparation method of the culture medium are as follows: (1) LB liquid culture medium: Yeast powder 5 g / L, peptone 10 g / L, NaCl 10 g / L, natural pH.

[0056] (2) Wastewater solid culture medium: Solution A: The wastewater after dilution and nutrient adjustment in this example is filtered and sterilized with a sterile 0.22 μm filter membrane.

[0057] Solution B: Prepare a 4% agar solution with distilled water and sterilize it at 121 °C for 20 min.

[0058] Mix Solution A and Solution B at a ratio of 1:1 (v / v) and pour it into a sterile petri dish to obtain the wastewater solid separation culture medium.

[0059] 1.6 Primary screening of strains The strains are activated in a 96-well plate containing LB liquid culture medium. After culturing for 2 days, each bacterial solution is inoculated into a 96-well plate containing the diluted and nutrient-adjusted wastewater at an inoculation amount of 1% using a high-throughput breeding platform. The system is placed in a micro oscillator and cultured at 30 °C. Select the strains with OD 600 > 0.5 within 3 days using an enzyme-labeled instrument to screen the strains with rapid growth in high-concentration cyanide wastewater, and use them as the re-screened strains I.

[0060] Result: A total of 5 re-screened strains I are obtained.

[0061] 1.7 Re-screening of strains After activating the above-mentioned secondary screening strain I in LB liquid medium for 2 days, inoculate each bacterial liquid into a test tube containing 3 mL of wastewater after dilution and nutrient adjustment at an inoculation amount of 1%. The system is cultured at 150 r / min and 30 °C. Select the strains with a COD removal rate of ≥50% in the system within 5 days, and repeatedly streak the strains on the wastewater solid medium to obtain the strains that can stably grow on the wastewater as the secondary screening strain II.

[0062] Result: One strain of the secondary screening strain II was obtained, and the strain name is 324B6.

[0063] 1.8 Strain identification 1.8.1 16S rDNA sequencing and alignment Use a genomic DNA extraction kit to extract the genomic DNA of strain 324B6, and perform molecular biological identification by PCR amplification of 16S rDNA and sequencing. The upstream primer and downstream primer used for PCR amplification are respectively: Upstream primer 27F: 5'-GAGAGTTTGATCMTGGCTCAG-3' Downstream primer 1492R: 5′-TACGGYTACCTTGTTACGAC-3′ The purification and sequencing of the PCR product were both completed by Sangon Biotech (Shanghai). The 16S rDNA sequence of strain 324B6 obtained is shown in SEQ ID NO:1, with a sequence length of 1262 bp. The specific sequence is as follows: >324B6 GGTGAGTAATGTATCGGAACGTGCCCAGTAGCGGGGGATAACTACTCGAAAGAGTGGCT AATACCGCATACGCCCTACGGGGGAAAGGGGGGGATCGCAAGACCTCTCACTATTGGAG CGGCCGATATCGGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCGTCGATCCGTA GCTGGTTTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACG GGAGGCAGCAGTGGGGAATTTTGGACAATGGGGGGAACCCTGATCCAGCCATCCCGCG TGTGCGATGAAGGCCTTCGGGTTGTAAAGCACTTTTGGCAGGGAAGAAAAGGCTCTGG TTAATACCCGGAGCTGCTGACGGTACCTGCAGAATAAGCACCGGCTAACTACGTGCCAG CAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGCGTGC GCAGGCGGTTTGGCAAGAAGGATGTGAAATCCCGGGGCTTAACCTCGGAACTGCATTCT TAACTGCCAGGCTAGAGTATGTCAGAGGGGGGTAGAATTCCGCGTGTAGCAGTGAAATG CGTAGAGATGCGGAGGAATACCGATGGCGAAGGCAGCCCCCTGGGATAATACTGACGCT CATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAA CGATGTCAACTAGCTGTTGGGGCCTTCGGGCCTTAGTAGCGCAGCTAACGCGTGAAGTT GACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGC ACAAGCGGTGGATGATGTGGATTAATTCGATGCAACGCGAAAAaCCTTACCTACCCTTGA CATGTCTGGAATCCTTTAGAGATAGAGGAGTGCTCGCAAGAGAACCGGAACACAGGTG CTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGC AACCCTTGTCATTAGTTGCTACGAAAGGGCACTCTAATGAGACTGCCGGTGACAAACCG GAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTC ATACAATGGTCGGGACAGAGGGTCGCCAACCCGCGAGGGGGAGCCAATCCCAGAAACC CGATCGTAGTCCGGATTGCAGTCTGCAACTCGACTGCATGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATAC。

[0064] The 16S rDNA sequence of strain 324B6 was aligned in the EzBioCloud database, and the results are shown in Table 3 - the alignment results showed that the most closely related species was Pusillimonas noertemannii DSM 10065 T , and the 16S rDNA sequence similarity was 97.77%.

[0065] Table 3 Alignment information of the 16S rDNA sequence of the strain Strain number The most closely related species in 16S rDNA sequence alignment Similarity 324B6 <![CDATA[Pusillimonas noertemannii DSM 10065 T > 97.77％ 1.8.2 Physiological and biochemical characteristics Strain 324B6 was a Gram-negative bacterium, with positive oxidase and catalase activities. The main fatty acids were C 16:0 , C 17:0 cyclo, C 18:0 , C 19:0 cycloω8c. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and unidentified amino lipids. The main respiratory quinone was Q-8, and the genomic (G + C) content was 60.6 mol%. These characteristics were basically consistent with those of the genus Pusillimonas.

[0066] The suitable temperature range for the growth of strain 324B6 is 20 - 45 °C (optimum 35 °C), the suitable pH range for growth is 5.0 - 10.0 (optimum 7.5 - 8.0), the suitable NaCl range for growth is 0 - 10% (optimum 0.5% - 1%), and the suitable Na2SO4 range for growth is 0 - 15% (optimum 3%). The cell size is 0.5 - 1.0 μm in length and 0.2 - 0.5 μm in width. When cultured on LB medium at 30 °C for 2 days, the colonies are white, transparent, and have smooth edges. The strain is positive for nitrate reduction and can produce indole. β-galactosidase, gelatinase, α-glucosidase (starch hydrolysis), β-glucosidase, alkaline phosphatase, arginine dihydrolase, and cysteine arylamidase are positive; acid phosphatase, esterase (C4), esterase (C8), and leucine arylamidase are negative. It can utilize acetic acid, ethanol, L-trehalose, glycogen, L-arabinose, D,L-lactic acid, L-rhamnose, citric acid, glucose, D-sucrose, D-maltose; it cannot utilize adipic acid, L-arabinose, capric acid, D-glucose, L-histidine, L-malic acid, L-mannose, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, D-maltose, and salicylic acid as carbon sources. These physiological and biochemical characteristics are different from those of Pusillimonas noertemannii and also different from other species within the genus Pusillimona.

[0067] 1.8.3 Identification results Based on the comparison results of the 16S rDNA sequence and physiological and biochemical characteristics of strain 324B6, strain 324B6 was identified as a new species within the genus Pusillimonas (in this invention, the polyphasic taxonomy identification method used in strain identification was adopted, and this method was also used in papers such as "Analysis of the Cultivable Bacterial Diversity in the Northern South China Sea and Polyphasic Taxonomy Study of Two Bacteria in the Deep Sea Area" and "Combined Traditional Polyphasic Taxonomy and High-Throughput Sequencing to Study Extreme Environment Microbial Resources and Evolution"). In this invention, the new species has not been named yet and is referred to as "sp.", and this strain is called Pusillimonas sp.324B6.

[0068] Example 2: Ammoniation and removal effect of strain 324B6 on cyanide (bench-scale test) 2.1 PBR (Pioneer Bioreactor) biological treatment bench-scale test device The test device is a continuous inflow and outflow device to simulate the on-site treatment system to the greatest extent to test the treatment effect of the strain on high-nitrate wastewater. The whole set of devices is as Figure 2As shown in the figure, it is composed of a sequentially connected inlet tank, PBR-1 tank, PBR-2 tank, and outlet tank. The inlet tank is used to supplement nutrients and accommodate wastewater, and a stirring system is installed at the bottom; both the PBR-1 tank and the PBR-2 tank are bacterial biochemical treatment tanks, and an aeration system is installed at the bottom. The effective volume of each tank body is 3L, and the inlet and outlet methods are bottom-in and top-out; the wastewater in the inlet tank is lifted to the PBR-1 tank by a peristaltic pump, and the wastewater in the PBR-1 tank is lifted to the PBR-2 tank by a peristaltic pump. The outlet tank is used to collect the treated wastewater.

[0069] 2.2 Inlet The inlet water is the wastewater diluted in Example 1 without nutrient adjustment.

[0070] 2.3 Preparation of seed liquid The bacterial liquid of strain 324B6 preserved with glycerol was streaked onto a sterile wastewater solid medium (prepared according to the method in Example 1), and after culturing at 30°C for 2 days, single colonies were picked into an LB liquid medium (prepared according to the method in Example 1) and cultured at 30°C and 150 rpm until the OD 600 value reached about 1.0, and the seed liquid of strain 324B6 was obtained.

[0071] 2.4 Addition of strains When the PBR-1 tank and the PBR-2 tank are started, they are filled with clear water and the pH is adjusted to about 7.0, and then the seed liquid of strain 324B6 is inoculated into the PBR-1 tank and the PBR-2 tank at an inoculation amount of 15%, and aeration is started and mixed evenly.

[0072] 2.5 Condition control By adjusting the flow rate of the peristaltic pump, the HRT of the inlet water in the PBR-1 tank and the PBR-2 tank is controlled to be 4 days respectively, and the total HRT is 8 days. Control the OD≥2mg / L and the temperature at 25-30°C in the PBR-1 tank and the PBR-2 tank.

[0073] 2.6 Treatment effect It was continuously operated for 28 days, and during this period, the inlet water quality and the outlet water quality of the PBR-1 tank and the PBR-2 tank were monitored. The results are shown in Figure 3 、 Figure 4 and Table 4 (Table 4 is the data during the stable operation period, that is, the average value of the last 14 days of the test); samples were taken from the PBR-1 tank and microscopic examination was carried out during the stable operation period. The results are shown in Figure 5 .

[0074] Table 4 Summary of pilot-scale treatment effects It can be seen from the above data that: Strain 324B6 grows well and has high activity in the wastewater system, indicating that this strain can well adapt to the high-concentration cyanide wastewater. Strain 324B6 can simultaneously achieve efficient treatment of COD and TOC, with a treatment rate of over 76% in 8 days; it not only realizes the efficient conversion of organic nitrogen (the conversion rate is over 74%, and the increase in the NH3-N index indicates that the organic nitrogen in the wastewater has been converted into NH3-N), but also achieves the efficient removal of TN (the removal rate is about 56%); it also efficiently removes the characteristic pollutant cyanide, with a removal rate of 97.9%.

[0075] Example 3: Ammoniation and removal effect of strain 324B6 on cyanide (pilot-scale test) 3.1 PBR test device The test device is an enlarged version of the test device in Example 2, and the effective volume of each tank is 180L.

[0076] 3.2 Influent water quality The influent water quality is shown in Table 5.

[0077] Table 5 Pilot-scale influent water quality Index Unit Value COD mg / L 35663～37683 <![CDATA[NH3-N]]> mg / L 386.4 TP mg / L 0 <![CDATA[NO2 - -N]]> mg / L 0 <![CDATA[NO3 - -N]]> mg / L 0 TN mg / L 2000 TDS ％ 4.50 pH / 10 3.3 Preparation of seed liquid The bacterial liquid preserved with glycerol was streaked onto a sterile wastewater solid medium (prepared according to the method in Example 1). After culturing at 30°C for 2 days, single colonies were picked into an LB liquid medium (prepared according to the method in Example 1) and cultured at 30°C and 150 rpm until the OD 600 value reached about 1.0, and the seed liquid of strain 324B6 was obtained.

[0078] 3.4 Addition of strains When starting up, the PBR-1 tank and the PBR-2 tank were filled with clear water, the pH was adjusted to about 7.0, and then the seed liquid of strain 324B6 was inoculated into the PBR-1 tank and the PBR-2 tank at an inoculation amount of 15%. Aeration was started and mixed evenly.

[0079] 3.5 Condition control By adjusting the flow rate of the metering pump, the HRT of the influent water in the PBR-1 tank and the PBR-2 tank was controlled to be 4 days respectively, and the total HRT was 8 days. Control the OD≥2mg / L and the temperature at 25-30°C in the PBR-1 tank and the PBR-2 tank.

[0080] 3.6 Treatment effect It was continuously operated for 30 days. During this period, the influent water quality and the effluent water quality of the PBR-1 tank and the PBR-2 tank were monitored. The results are shown in Figure 6 、 Figure 7 and Table 6 (Table 6 is the data during the stable operation period, that is, the average value of the last 14 days of the test).

[0081] Summary of Pilot-scale Treatment Effects in Table 6 As can be seen from the above data: After the pilot-scale test, strain 324B6 can not only achieve a COD removal rate of 90%, TN and organic nitrogen removal rates of 73.4% and 48.8% respectively, but also achieve the efficient removal of 7 characteristic pollutants, with the removal rates all reaching or approaching 100%, indicating the engineering application feasibility of strain 324B6 in treating high-concentration cyanide wastewater.

[0082] Example 4: Denitrification Effect of Strain 324B6 under Aerobic Conditions (Laboratory-scale Test) 4.1 Wastewater Sample The wastewater is a high-nitrate wastewater from a new material in Hubei, and its main component is sodium nitrate. The wastewater quality is shown in Table 7.

[0083] Table 7 Wastewater Quality Index Unit Value COD mg / L 80364 TOC mg / L 41391 <![CDATA[NH3-N]]> mg / L 0 TP mg / L 5 <![CDATA[NO2 - -N]]> mg / L 0 <![CDATA[NO3 - -N]]> mg / L 10000 TN mg / L 10000 TDS ％ 1.20 pH / 5 4.2 Culture Medium The formula and preparation method of the culture medium are as follows: (1) LB Liquid Medium: Yeast powder 5 g / L, peptone 10 g / L, NaCl 10 g / L, pH natural.

[0084] (2) LB Solid Medium: On the basis of the formula of LB liquid medium, add agar 20 g / L.

[0085] (3) RM Nutrient Solution: Rpf crude extract 10 mL, MgSO4·7H2O 0.3 g / L, MnSO4·H2O 0.2 g / L, CaCl2 0.2 g / L, FeSO4·7H2O 0.2 g / L, Na2MoO4·2H2O 0.008 g / L, CuSO4·5H2O 0.006 g / L, ZnSO4·7H2O 0.009 g / L, CoCl2·6H2O 0.0001 g / L, H3BO3 0.015 g / L, pH = 6. The preparation method of Rpf crude extract refers to Patent ZL202211094469.7 A Complex for Promoting the Isolation and Cultivation of Anaerobic Microorganisms and Its Application.

[0086] 4.3 Test Device The test device is a continuous influent and effluent device to simulate the on-site treatment system to the greatest extent to test the treatment effect of the strain on high-nitrate wastewater. The whole set of devices is as Figure 8As shown in the figure, it is composed of a sequentially connected inlet pond, a strain pond, and an outlet pond. The effective volume of each pond is 3L. The inlet pond is used to supplement nutrients and accommodate wastewater, and a stirring system is installed at the bottom. The strain treatment pond is a biochemical treatment pond for strains, and an aeration system is installed at the bottom. The wastewater in the inlet pond is lifted to the strain pond by a peristaltic pump; the outlet pond is used to collect the treated wastewater.

[0087] 4.4 Inlet The inlet water is the high-nitrate wastewater in this embodiment, and 0.5 g / L of KH2PO4, 1 mL / L of RM nutrient solution, and a certain amount of glucose are added, and adjusted to a certain pH.

[0088] 4.5 Adding Strains The strain 392A9 is cultured on an LB solid medium at 30 °C for 2 d. Single colonies are picked and inoculated into an LB liquid medium, and cultured at 150 r / min and 30 °C until the logarithmic phase to obtain the seed liquid of the strain 392A9.

[0089] 1 mL / L of RM nutrient solution is added to the strain pond, the starting pH of the strain pond system is adjusted to 7.0, and the seed liquid of the strain 392A9 is inoculated into the strain treatment pond at an inoculation amount of 10%.

[0090] 4.6 Influence of Inlet Water pH on Aerobic Denitrification Effect No additional glucose is added to the inlet water. The DO in the strain pond is controlled to be ≥2.0 mg / L, and the water temperature is 25 - 30 °C. The inlet water pH is set to 5.0, 6.0, 7.0, 8.0, and 9.0 respectively. Check the treatment effect of the strains on the wastewater within 10 d of the HRT in the strain pond. The results are shown in Figure 9 . Figure 9 In, the denitrification rate is the TN removal rate.

[0091] The results show that when the inlet water pH is adjusted between 5.0 and 6.0, the denitrification rate reaches 50%. Then, as the inlet water pH increases, the denitrification rate gradually decreases. The reason is speculated as follows: In the aerobic denitrification reaction stage, the pH of the strain pond system shows an upward trend. The higher the inlet water pH, the higher the pH of the strain pond system. For example, when the inlet water pH is 5.0, the pH of the strain pond finally stabilizes at about 9.0; when the inlet water pH is 9.0, the pH of the strain pond system is as high as 11.0, and the ultra-high pH of the system inhibits the growth and metabolism of the strains.

[0092] Conclusion: The strain 392A9 can carry out aerobic denitrification within the range of inlet water pH 5.0 - 9.0. The inlet water pH should be controlled between 5.0 and 6.0, and the best is 5.0.

[0093] 4.7 Influence of HRT on Aerobic Denitrification Effect Adjust the influent pH to 5.0, add an additional 15 g / L of glucose, control the DO in the strain pool ≥ 2.0 mg / L, and the water temperature at 25 - 30 °C. Observe the influence of different HRTs (5 d, 6 d, 7 d, 8 d, 9 d, 10 d) in the strain pool on the treatment effect of the strain. The results are shown in Figure 10 . Figure 10 In, the denitrification rate is the TN removal rate.

[0094] The results show that: within the range of HRT from 5 to 10 d, as the HRT extends, the denitrification rate gradually increases. When the HRT is 9 d, the maximum denitrification rate reaches 99.5%.

[0095] Conclusion: The optimal HRT of the strain pool for aerobic denitrification by strain 392A9 is 9 d.

[0096] 4.8 Aerobic wastewater treatment effect under the optimal conditions Adjust the influent pH to 5.0, add an additional 15 g / L of glucose, control the DO in the strain pool ≥ 2.0 mg / L, and the water temperature at 25 - 30 °C. Observe the treatment effect of the strain on the wastewater within 9 d of HRT in the strain pool. The results are shown in Table 8.

[0097] Table 8 Treatment effect of strain 392A9 on high - nitrate wastewater by aerobic process Inlet water Outlet water Removal rate Volumetric loading HRT Unit mg / L mg / L ％ <![CDATA[kg / (m 3 ·d)]]> d COD 98567 9810 90.0 9.9 9 TOC 54754 5436 90.1 5.5 9 <![CDATA[NO3 - -N]]> 10000 55 99.5 1.1 9 TN 10000 55 99.5 1.1 9 Note: In Table 8, the influent COD and TOC of the wastewater are the data after adding glucose.

[0098] The results show that: Strain 392A9 can directly treat wastewater with a nitrate - nitrogen concentration of up to 10,000 mg / L, and achieve a denitrification rate of 99.5% and a denitrification volume load of 1.1 kg / (m 3 ·d) at HRT of 9 d, and simultaneously achieve efficient removal of wastewater COD and TOC, with a removal rate of approximately 90%. During aerobic denitrification, the required TOC / TN is approximately 5.0 and COD / TN is approximately 8.9.

[0099] Example 5: Denitrification effect of strain 392A9 under anaerobic conditions (bench - scale test) 5.1 Test device The test device is a continuous influent and effluent device, which simulates the on - site treatment system to the greatest extent to test the treatment effect of the strain on high - nitrate wastewater. The whole set of devices is as Figure 11 shown, consisting of an influent pool, a strain pool, and an effluent pool connected in sequence. The effective volume of each pool is 3 L. The influent pool is used to supplement nutrients and accommodate wastewater, and a stirring system is installed at the bottom. The strain treatment pool is a biochemical treatment pool for the strain, and a stirring system is installed at the bottom. The wastewater in the influent pool is lifted to the strain pool by a peristaltic pump; the effluent pool is used to collect the treated wastewater.

[0100] 5.2 Influent Same as Example 4.

[0101] 5.3 Seeding of Bacteria Same as Example 4.

[0102] 5.4 Influence of Influent pH on Anaerobic Denitrification Effect No additional glucose was added to the influent. The DO in the bacteria pool was controlled at ≤ 0.5 mg / L, and the water temperature was 25 - 30 °C. The influent pH was set at 5.0, 6.0, 7.0, 8.0, and 9.0 respectively. The treatment effect of the bacteria on the wastewater within 10 days of HRT in the bacteria pool was observed. The results are shown in Figure 12 . Figure 12 In, the denitrification rate is the TN removal rate.

[0103] The results showed that when the influent pH was adjusted between 6.0 and 7.0, the denitrification rate reached 50% in both cases, and the pH of the bacteria pool system was stable at around 9.0. However, when the influent pH was lower or higher, the denitrification rate decreased. Presumably, during the anaerobic denitrification reaction stage, when the influent pH was 5.0, the pH of the bacteria pool finally stabilized at around 7.5; while when the influent pH was 8.0 - 9.0, the pH of the bacteria pool system was as high as 10.0, and the excessively high pH of the system inhibited the growth and metabolism of the bacteria.

[0104] Conclusion: Strain 392A9 can carry out anaerobic denitrification within the range of influent pH 5.0 - 9.0. The influent pH should be controlled between 6.0 and 7.0, and the optimal value is 6.0.

[0105] 5.5 Influence of HRT on Anaerobic Denitrification Effect The influent pH was adjusted to 6.0, and 3 g / L of glucose was added additionally. The DO in the bacteria pool was controlled at ≤ 0.5 mg / L, and the water temperature was 25 - 30 °C. The influence of different HRTs (5 d, 10 d, 15 d, 20 d) in the bacteria pool on the treatment effect of the bacteria was observed. The results are shown in Figure 13 . Figure 13 In, the denitrification rate is the TN removal rate.

[0106] The results showed that within the range of HRT from 5 to 10 d, the denitrification rate gradually increased with the extension of HRT. When the HRT was 5 d, the denitrification rate was only 22.2%; when the HRT was 15 d, the maximum denitrification rate reached 98.9%, and further extension of the HRT did not increase the denitrification rate.

[0107] Conclusion: The optimal HRT of the bacteria pool for strain 392A9 to carry out anaerobic denitrification is 15 d.

[0108] 5.6 Anaerobic Wastewater Treatment Effect under Optimal Conditions Adjust the influent pH to 6.0, add an additional 3 g / L of glucose, control the DO in the strain pool ≤ 0.5 mg / L, and the water temperature at 25 - 30 °C. Check the treatment effect of the strain on the wastewater within 15 days of HRT in the strain pool. The results are shown in Table 9.

[0109] Table 9 Treatment Effect of Strain 392A9 on Anaerobic Process for High Nitrate Wastewater Inlet water Outlet water Removal rate Volumetric loading HRT Unit mg / L mg / L ％ <![CDATA[kg / (m 3 ·d)]]> d COD 85364 20410 76.1 4.3 15 TOC 42796 9365 78.1 2.2 15 <![CDATA[NO3 - -N]]> 10000 106 98.9 0.7 15 TN 10000 106 98.9 0.7 15 Note: In Table 9, the influent COD and TOC of the wastewater are the data after adding glucose.

[0110] The results show that strain 392A9 can directly treat wastewater with a nitrate nitrogen concentration of up to 10,000 mg / L. Within 15 days of HRT, the denitrification rate reaches 98.9%, and the denitrification volume load reaches 0.7 kg / (m 3 ·d). At the same time, efficient removal of wastewater COD and TOC is achieved, with a removal rate of approximately over 75%. During anaerobic denitrification, the required TOC / TN is approximately 3.4 and COD / TN is approximately 6.6.

[0111] Example 6: Denitrification Treatment of High - Concentration Cyanide - Containing Wastewater 6.1 Wastewater Treatment System The wastewater treatment system consists of a high - concentration adjustment tank, a pioneer bioreactor (PBR), Air Flotation Tank 1#, an enhanced aerobic nitrification (CLEAN) device, an enhanced anaerobic denitrification device, and Air Flotation Tank 2# connected in sequence. Among them, the PBR adopts the pioneer bioreactor in Example 1 of the applicant's patent ZL202122101338.4, the enhanced aerobic nitrification device adopts the integrated nitrifying bacteria cultivation device in Example 1 of the applicant's patent ZL202321091675.2, the enhanced anaerobic denitrification device adopts a tank body with a stirring device inside, and Air Flotation Tank 1# and Air Flotation Tank 2# adopt a partial - reflux pressurized jet - dissolved air horizontal - flow combined air flotation.

[0112] 6.2 Wastewater Denitrification Treatment Process The wastewater denitrification treatment process is as Figure 1 shown.

[0113] 6.2.1 Water Quality Adjustment In the high - concentration adjustment tank, mix the high - concentration cyanide - containing wastewater with low - concentration wastewater (domestic sewage), and then adjust the pH to 7.5 - 8.0 using NaOH and H2SO4.

[0114] 6.2.2 Bio - pretreatment startup phase: Streak the bacterial solution of strain 324B6 preserved in glycerol onto a sterile wastewater solid medium, and incubate it at 30 °C for 2 days. Then pick a single colony and transfer it to an LB liquid medium, and incubate it at 30 °C and 150 rpm until the OD600 value reaches about 1.0 to obtain the seed solution of strain 324B6. Then inoculate the seed solution of strain 324B6 into the PBR at an inoculation amount of 15%, fill the PBR with low - concentration wastewater, start aeration, control OD ≥ 2 mg / L, mix evenly, and adjust the system pH = 7.0 with NaOH or H2SO4. The duration of the startup phase is 6 days (starting from when the strain is added to the PBR, excluding the previous strain preparation).

[0115] The formula of the above - mentioned LB liquid medium is as follows: yeast powder 5 g / L, peptone 10 g / L, NaCl 10 g / L, and the pH is natural.

[0116] The preparation method of the above - mentioned wastewater solid medium is as follows: Solution A: Filter and sterilize the mixed wastewater in this example with a sterile 0.22 - μm filter membrane. Solution B: Prepare a 4% agar solution with distilled water and sterilize it at 121 °C for 20 min.

[0117] Mix Solution A and Solution B at a ratio of 1:1 (v / v) and pour it into a sterile petri dish to obtain the wastewater solid separation medium.

[0118] Wastewater biological pretreatment: Use a metering pump to pump the water from the high - concentration regulation tank into the PBR, control the HRT of the wastewater in it to be 8 days, and control OD ≥ 2 mg / L (using a blower for oxygen supply), and the water temperature is 28 - 30 °C. Use a dosing pump to add KH2PO4 to the PBR, and the daily addition amount is 0.1 g / L. Slowly feed water in the early stage, and accelerate the water inlet after the OD of the strain concentration in the PBR 600 reaches above 1.0.

[0119] 6.2.3 Air flotation 1# Pass the PBR effluent into air flotation tank 1#, add PAC and PAM for flocculation air flotation, and the dosing amounts are 200 mg / L and 15 mg / L respectively.

[0120] 6.2.4 Enhanced aerobic nitrification startup phase: Add the nitrifying bacteria of Bei Huo Biotechnology (Shanghai) Co., Ltd. at an inoculation amount of 30%, fill the CLEAN device with low - concentration wastewater, control DO ≥ 2 mg / L, and add 0.5 g / L of (NH4)2SO4 every day to activate the nitrification function, and use Na2CO3 to control the system pH to 8.0. When the nitrification rate in the CLEAN device reaches 80%, start to introduce the effluent from air flotation tank 1#.

[0121] Nitrification treatment of wastewater: The effluent from the 1# flotation tank is introduced into the CLEAN device. The nitrification section is designed according to a nitrification load of 0.1 - 0.25 kg NH3-N / (m 3 ·d), controlling DO ≥ 2 mg / L (using a blower for oxygen supply), and the water temperature is 28 - 30 °C.

[0122] 6.2.5 Enhanced anaerobic denitrification startup stage: The seed liquid of strain 392A9 (prepared according to the method in Example 4) is inoculated into the enhanced anaerobic denitrification device at an inoculation amount of 10%. The enhanced anaerobic denitrification device is filled with low-concentration wastewater, controlling DO ≤ 0.5 mg / L, and the system pH is about 7.0. Glucose is added at 1 - 3 g / L per day. The startup stage lasts for 7 days (starting from when the strain is added to the PBR, excluding the previous strain preparation).

[0123] Denitrification treatment of wastewater: The effluent from the CLEAN device is introduced into the enhanced anaerobic denitrification device. The denitrification section is designed according to a denitrification load of 0.5 - 0.7 kg NO3 - -N / (m 3 ·d), and controlling DO ≤ 0.5 mg / L, and the water temperature is 28 - 30 °C.

[0124] 6.2.6 Flotation 2# Same as flotation 1#. Part of the effluent from the 2# flotation tank is refluxed to the PBR, and the reflux ratio is 150%.

[0125] 6.3 Wastewater denitrification treatment effect It is continuously operated for 30 days. During this period, the effluent water quality of the high-concentration regulation tank, PBR, CLEAN device, and enhanced anaerobic denitrification device is monitored. The average values during the stable operation period (i.e., the last 14 days of the test) are shown in Table 10.

[0126] Table 10 Denitrification treatment effect of cyanide wastewater The results show that: Using the strain 324B6 of the present invention for biological pretreatment can ammoniate (convert to NH3-N) and remove cyanide in the wastewater. Then, through nitrification treatment, NH3-N can be converted into NO3 - -N and NO2 - -N. Then, using the strain 392A9 of the present invention for denitrification treatment can further remove NO3 - -N and NO2 - -N, thereby achieving the denitrification of cyanide wastewater.

[0127] The raw materials and equipment used in the present invention, unless otherwise specified, are all common raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0128] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A PBR biological pretreatment method for high-concentration cyanide wastewater, characterized in that, It includes the following steps: (1) Detect the total cyanide concentration in the cyanide-containing wastewater. When the detected total cyanide concentration is higher than 1300 mg / L, adjust the water quality until the total cyanide concentration is not higher than 1300 mg / L, and then proceed to step (2); (2) Introduce the cyanide-containing wastewater into a pioneer bioreactor inoculated with Micromonospora sp. Pusillimonas sp. 324B6 to perform ammoniation to remove cyanide and obtain pretreated wastewater; the Micromonospora sp. 324B6 was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on November 8, 2023, with the deposit number of CGMCC No. 28905.

2. The biological pretreatment method according to claim 1, wherein Before step (2), adjust the COD value of the wastewater to not higher than 40000 mg / L, the TN value to not higher than 2000 mg / L, the NH3-N concentration to not higher than 2000 mg / L, the TDS value to not higher than 2%, and the pH to 7.5 - 8.

0.

3. The biological pretreatment method according to claim 1, wherein, In step (2), in the pioneer bioreactor, control the dissolved oxygen content to be not lower than 2 mg / L, and the water temperature to be 25 - 30 °C.

4. The biological pretreatment method according to claim 1, characterized in that In step (2), during the biological pretreatment, add KH2PO4 to the pioneer bioreactor, and the dosage is 0.1 g / L.

5. A method for denitrification of high-concentration cyanide wastewater, characterized in that, It includes the following steps: (I) Use the biological pretreatment method described in any one of claims 1 - 4 to perform biological pretreatment on the cyanide-containing wastewater to obtain pretreated wastewater; (II) Feed the pretreated wastewater into a nitrification device inoculated with nitrifying bacteria for nitrification treatment to obtain nitrified wastewater; (III) Feed the nitrified wastewater into a denitrification device inoculated with denitrifying bacteria for denitrification treatment to obtain denitrified wastewater.

6. The denitrification method according to claim 5, wherein In step (III), the denitrifying bacteria are Paracoccus denitrificans ( Paracoccus denitrificans ), strain 392A9, which was deposited at the China General Microbiological Culture Collection Center on October 20, 2023, with the deposit number CGMCC No. 28691.

7. The denitrification method according to claim 6, characterized in that, In step (III), in the denitrification device, control the dissolved oxygen content to be not higher than 0.5 mg / L, and the water temperature to be 25 - 30 °C.

8. The denitrification method according to claim 5, characterized in that, Before step (II), perform flocculation and air flotation on the pretreated wastewater to remove the bacteria therein.

9. The denitrification method according to claim 7, wherein After step (III), perform flocculation and air flotation on the denitrified wastewater to remove the bacteria therein.

10. The denitrification method according to claim 9, characterized in that, After performing flocculation and air flotation on the denitrified wastewater, part of the wastewater is refluxed to the pioneer bioreactor, and the reflux ratio is 100 - 200%.

Images