A method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process

Abstract

The present invention aims at solving the problem of low denitrification efficiency in view of the characteristics of high nitrogen content, high concentration of organic pollutants and complex composition, high biological toxicity and low C / N of fermented antibiotic pharmaceutical wastewater, and discloses a method for deep denitrification of pharmaceutical wastewater based on synchronous short-term nitrification and denitrification process. The method cultivates SND aerobic synchronous short-term nitrification and denitrification bio-enhanced bacterial flora under aerobic conditions, and inoculates it in a reactor containing pharmaceutical wastewater, and controls the dissolved oxygen concentration and temperature, and utilizes the organic carbon source in the wastewater to achieve short-term synchronous removal of ammonia nitrogen and nitrate nitrogen. The synchronous short-term nitrification and denitrification denitrification technology obtained in this way can not only realize synchronous short-term nitrification and denitrification in the same reaction tank in a true sense, but also make full use of the organic carbon source in the raw water to achieve synchronous and efficient removal of total nitrogen and organic matter, providing reliable technical support for deep denitrification of fermented antibiotic pharmaceutical wastewater.

Description

Technical Field

[0001] The invention relates to wastewater treatment, in particular to a method for deep denitrification of pharmaceutical wastewater based on a synchronous short-range nitrification and denitrification process, and belongs to the technical field of sewage treatment. Background Art

[0002] Pharmaceutical wastewater is internationally recognized as one of the serious sources of environmental pollution. High-concentration fermentation antibiotic wastewater includes high-concentration yeast solution, refining residual liquid, solvent recovery residual liquid, waste filtrate, etc. discharged from the fermentation workshop. The concentration of organic pollutants is high. For example, the COD concentration of waste acid water, waste mother liquor and other waste liquids can reach more than 20,000 mg / L; the nitrogen content is high, and the total nitrogen can reach 700-1000 mg / L, mainly in the form of organic nitrogen and ammonia nitrogen; the chroma is high and the suspended solids concentration is high. In particular, antibiotics in water have an inhibitory and killing effect on microorganisms, and are highly toxic and difficult to biodegrade. In recent years, with the upgrading of fermentation pharmaceutical technology, the control of the environment has become increasingly strict, and the requirements for the discharge of total nitrogen in the effluent have become more stringent.

[0003] Due to the toxicity of antibiotics in pharmaceutical wastewater and the lack of carbon sources in the subsequent biological treatment process, the traditional biological treatment process cannot meet the requirements for total nitrogen removal, and the denitrification efficiency is 70-80%. When a large amount of carbon source is added by adding carbon sources such as glucose and methanol or supplementing raw water, it still cannot meet the emission standards. In addition, due to the large amount of carbon source added, there is a risk of exceeding the standard, increasing sludge production and high operating costs.

[0004] The theory of simultaneous nitrification and denitrification is to carry out nitrification and denitrification reactions simultaneously in the same effective volume, which can effectively reduce aeration energy consumption and carbon source dosage, and has great application potential. However, the currently operating nitrification and denitrification processes often integrate independent tanks to carry out nitrification and denitrification reactions separately, or achieve different dissolved oxygen concentration gradients in the same reactor to achieve simultaneous nitrification and denitrification. Such water treatment processes that rely on the macro-environment theory have high energy consumption, complex processes, low removal rates, and unsatisfactory operating results.

[0005] Based on the above problems, developing a deep denitrification process for fermentation antibiotic pharmaceutical wastewater with higher efficiency and lower energy consumption is a major challenge facing the fermentation pharmaceutical industry and is also the key to technological upgrading. Summary of the invention

[0006] The purpose of the present invention is to provide a method for deep denitrification of pharmaceutical wastewater, which can realize synchronous short-range nitrification and denitrification in the same reaction tank in a true sense, and helps to reduce aeration energy consumption and solve the problem of insufficient carbon source, in view of the shortcomings of the prior art.

[0007] The present invention cultivates SND (aerobic synchronous short-range nitrification and denitrification) bio-enhanced bacterial flora under aerobic conditions, inoculates it in a reactor containing pharmaceutical wastewater, controls the dissolved oxygen concentration and temperature of the reactor, and utilizes the organic carbon source in the wastewater to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen.

[0008] The present invention proposes and deeply studies the theory of synchronous short-range nitrification and denitrification, and provides a new method for the biological denitrification of sewage, so that nitrogen can be efficiently removed under the condition of insufficient carbon source in low carbon-nitrogen ratio pharmaceutical wastewater. It fundamentally solves the problem of substandard total nitrogen in effluent during the denitrification treatment of pharmaceutical wastewater, and also provides a new idea for saving energy consumption.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for deep denitrification of pharmaceutical wastewater based on a synchronous short-range nitrification and denitrification process comprises the following steps:

[0011] 1) Picking 2 rings of Ochrobacterium, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii, and Paracoccus denitrificans respectively, transferring them to a nutrient solution, culturing them independently at 35-37° C. for 1-3 days, inoculating them into a proliferation medium at a volume ratio of 5-15%, culturing them independently at 35-37° C. for 1-3 days, and centrifuging them (5000-8000 rpm, 3-5 min) to obtain logarithmic growth phase cells of various bacteria respectively;

[0012] 2) washing the cells in the logarithmic growth phase with phosphate buffer for 1 to 3 times, and then taking 18 to 25% of Ochrobacterium, 14 to 18% of Stenotrophomonas maltophilia, 16 to 20% of Pseudomonas stutzeri, 20 to 25% of Citrobacter freundii and 17 to 27% of Paracoccus denitrificans respectively according to the volume ratio to obtain a SND bio-enhanced bacterial flora for aerobic synchronous short-range nitrification and denitrification;

[0013] 3) The SND bio-enhanced bacterial community is made into a bacterial suspension with an OD600 of 1.0 to 1.5 using sterile water, and inoculated into a reactor containing pharmaceutical wastewater at a ratio of 1 to 5%. The pharmaceutical wastewater enters the reactor after anaerobically treated in an anaerobic water distribution tank, and the dissolved oxygen concentration and temperature in the reactor are controlled, and the organic carbon source in the wastewater is used to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen.

[0014] Furthermore, the Ochrobactrum, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii and Paracoccus denitrificans described in step 1) were purchased from Guangdong Microbiological Culture Collection Center (Cat. No.: GDMCC 1.1609, GDMCC 1.552, GDMCC 1.1225, GDMCC 1.1031, GDMCC 1.335).

[0015] Furthermore, the main components of the nutrient solution in step 1) are: 10.0 g / L tryptone, 10.0 g / L NaCl, 5.0 g / L yeast extract powder, pH 6.8-7.2, and the rest is water.

[0016] Furthermore, the main components of the proliferation culture medium in step 1) are: 20.0 g / L casein, 3.0 g / L potassium dihydrogen phosphate, 3.0 g / L glucose, 5.0 g / L sodium chloride, and the rest is water.

[0017] Furthermore, the main components of the phosphate buffer described in step 2) are: 8.0 g / L sodium chloride, 7.98 g / L dipotassium hydrogen phosphate trihydrate, 2.04 g / L potassium dihydrogen phosphate, and the rest is water.

[0018] Furthermore, the mass ratio of C to N in the pharmaceutical wastewater entering the reactor in step 3) is 2.0 to 6.0.

[0019] Furthermore, the dissolved oxygen concentration in the reactor described in step 3) is controlled at 0.5-1.5 mg / L, and the temperature is controlled at 28-32°C.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) The synchronous short-range nitrification and denitrification technology established by SND bio-enhanced bacterial flora can truly achieve synchronous short-range nitrification and denitrification in the same reaction tank, which can effectively reduce aeration energy consumption and make full use of raw water to avoid secondary pollution caused by excessive sludge load;

[0022] 2) No alkalinity is added. Nitrification is an acid-producing process, while denitrification is an alkali-producing process. The synchronous short-range nitrification and denitrification technology can effectively maintain the pH stability in the reactor.

[0023] 3) The construction cost of the structure is low, and the process of nitrification and denitrification is realized in the same structure, which reduces the capital construction cost and saves the floor space. It effectively solves the difference in the demand of nitrifying bacteria and denitrifying bacteria for carbon source, alkalinity, sludge age and dissolved oxygen. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1a is the NH of the synchronous short-cut nitrification and denitrification process in Example 1 4 + -N, NO 2 - -N, NO 3 - -N, TN concentration change diagram;

[0025] Figure 1b is the NH of the synchronous short-cut nitrification and denitrification process in Example 1 4+ -N, TN removal efficiency and SND efficiency diagram;

[0026] Figure 2a is the NH of the synchronous short-cut nitrification and denitrification process in Example 2 4 + -N, NO 2 - -N, NO 3 - -N, TN concentration change diagram;

[0027] Figure 2b is the NH of the synchronous short-cut nitrification and denitrification process in Example 2 4 + -N, TN removal efficiency and SND efficiency diagram;

[0028] Figure 3a is the NH of the synchronous short-cut nitrification and denitrification process in Example 3 4 + -N, NO 2 - -N, NO 3 - -N, TN concentration change diagram;

[0029] Figure 3b is the NH of the synchronous short-cut nitrification and denitrification process in Example 3 4 + -N, TN removal efficiency and SND efficiency diagram. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] The present invention aims to solve the problem of low denitrification efficiency by targeting the characteristics of fermentation antibiotic pharmaceutical wastewater, such as high nitrogen content, high concentration of organic pollutants and complex composition, high biological toxicity and low C / N, and discloses a method for deep denitrification of pharmaceutical wastewater based on a synchronous short-range nitrification and denitrification process.

[0032] Example 1

[0033] 1) Pick up Ochrobacterium, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii, and Paracoccus denitrificans (all purchased from Guangdong Microbial Culture Collection Center, item number: GDMCC 1.1609, GDMCC 1.552, GDMCC1.1225, GDMCC 1.1031, GDMCC 1.335) and transfer 2 loops to the nutrient solution (whose main components are: tryptone 10.0 g / L, NaCl 10.0 g / L, yeast extract powder 5.0 g / L, pH 7.2, the rest is water), cultured independently at 37°C for 3 days, inoculated into proliferation medium (whose main components are: casein 20.0 g / L, potassium dihydrogen phosphate 3.0 g / L, glucose 3.0 g / L, sodium chloride 5.0 g / L, the rest is water) at a volume ratio of 15%, cultured independently at 37°C for 3 days, centrifuged (8000 rpm, 3 min), and obtained logarithmic growth phase cells of various bacteria respectively;

[0034] 2) washing the cells in the logarithmic growth phase with a phosphate buffer (whose main components are: 8.0 g / L sodium chloride, 7.98 g / L potassium hydrogen phosphate trihydrate, 2.04 g / L potassium dihydrogen phosphate, and the rest is water) for 3 times, and then taking 25% of Ochrobacterium, 18% of Stenotrophomonas maltophilia, 20% of Pseudomonas stutzeri, 20% of Citrobacter freundii and 17% of Paracoccus denitrificans in accordance with the volume ratio to obtain aerobic synchronous short-range nitrification and denitrification SND bio-enhanced bacterial flora;

[0035] 3) The SND bio-augmented bacterial community was made into a bacterial suspension with an OD600 of 1.5 using sterile water, and inoculated into a reactor containing pharmaceutical wastewater at a ratio of 5%. The pharmaceutical wastewater was anaerobic treated in an anaerobic water distribution tank before entering the reactor, the mass ratio of C to N was 6.0, the dissolved oxygen concentration in the reactor was controlled to be 1.5 mg / L, the temperature was 32°C, and the organic carbon source in the wastewater was used to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen.

[0036] The technology of this embodiment is used to denitrify 1L of pharmaceutical wastewater (influent water quality: ammonia nitrogen 392.10mg / L, total nitrogen 395.25mg / L, COD 2371.50mg / L). Figure 1a It can be seen that the reactor effluent contains only 27.60 mg NH 4 + -N / L, 9.80mg NO 2 - -N / L, 0.80mg NO 3 - -N / L, 38.2mg TN / L; at the same time Figure 1b As shown, NH 4 +The -N removal efficiency is 92.96%, the TN removal efficiency is 90.34%, and the SND efficiency is as high as 98.37%.

[0037] Example 2

[0038] 1) Pick up Ochrobacterium, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii, and Paracoccus denitrificans (all purchased from Guangdong Microbial Culture Collection Center, item number: GDMCC 1.1609, GDMCC 1.552, GDMCC1.1225, GDMCC 1.1031, GDMCC 1.335) and transfer 2 loops to the nutrient solution (whose main components are: tryptone 10.0 g / L, NaCl 10.0 g / L, yeast extract powder 5.0 g / L, pH 7.0, the rest is water), cultured independently at 36°C for 2 days, inoculated into proliferation medium (whose main components are: casein 20.0 g / L, potassium dihydrogen phosphate 3.0 g / L, glucose 3.0 g / L, sodium chloride 5.0 g / L, the rest is water) at a volume ratio of 10%, cultured independently at 36°C for 2 days, centrifuged (6500 rpm, 4 min), and obtained logarithmic growth phase cells of various bacteria respectively;

[0039] 2) washing the cells in the logarithmic growth phase twice with a phosphate buffer (whose main components are: 8.0 g / L sodium chloride, 7.98 g / L potassium hydrogen phosphate trihydrate, 2.04 g / L potassium dihydrogen phosphate, and the rest is water), and then taking 22% of Ochrobacterium, 16% of Stenotrophomonas maltophilia, 18% of Pseudomonas stutzeri, 24% of Citrobacter freundii and 20% of Paracoccus denitrificans in accordance with the volume ratio to obtain aerobic synchronous short-range nitrification and denitrification SND bio-enhanced bacterial flora;

[0040] 3) The SND bio-augmented bacterial community was made into a bacterial suspension with an OD600 of 1.2 using sterile water, and inoculated into a reactor containing pharmaceutical wastewater at a ratio of 3%. The pharmaceutical wastewater was anaerobic treated in an anaerobic water distribution tank before entering the reactor, the mass ratio of C to N was 4.0, the dissolved oxygen concentration in the reactor was controlled to be 1.0 mg / L, the temperature was 30°C, and the organic carbon source in the wastewater was used to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen.

[0041] The technology of this embodiment is used to denitrify 1L of pharmaceutical wastewater (influent water quality: ammonia nitrogen 649.13mg / L, total nitrogen 688.50mg / L, COD 2754.00mg / L). Figure 2a It can be seen that the reactor effluent contains only 31.10 mg NH 4 + -N / L, 14.70mg NO 2 - -N / L, 3.50mg NO3 - -N / L, 49.30mg TN / L; at the same time Figure 2b As shown, NH 4 + The -N removal efficiency was 95.21%, the TN removal efficiency was 92.84%, and the SND efficiency was as high as 94.17%.

[0042] Example 3

[0043] 1) Pick up Ochrobacterium, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii, and Paracoccus denitrificans (all purchased from Guangdong Microbial Culture Collection Center, item number: GDMCC 1.1609, GDMCC 1.552, GDMCC1.1225, GDMCC 1.1031, GDMCC 1.335) and transfer 2 loops to the nutrient solution (whose main components are: tryptone 10.0 g / L, NaCl 10.0 g / L, yeast extract powder 5.0 g / L, pH 6.8, the rest is water), cultured independently at 35°C for 1 day, inoculated into a proliferation medium (whose main components are: casein 20.0 g / L, potassium dihydrogen phosphate 3.0 g / L, glucose 3.0 g / L, sodium chloride 5.0 g / L, the rest is water) at a volume ratio of 5%, cultured independently at 35°C for 1 day, centrifuged (5000 rpm, 5 min), and obtained logarithmic growth phase cells of various bacteria respectively;

[0044] 2) washing the cells in the logarithmic growth phase with a phosphate buffer (whose main components are: 8.0 g / L sodium chloride, 7.98 g / L potassium hydrogen phosphate trihydrate, 2.04 g / L potassium dihydrogen phosphate, and the rest is water) once, and then taking 18% of Ochrobacterium, 14% of Stenotrophomonas maltophilia, 16% of Pseudomonas stutzeri, 25% of Citrobacter freundii and 27% of Paracoccus denitrificans in accordance with the volume ratio to obtain aerobic synchronous short-range nitrification and denitrification SND bio-enhanced bacterial flora;

[0045] 3) The SND bio-augmented bacterial community is made into a bacterial suspension with an OD600 of 1.0 using sterile water, and inoculated into a reactor containing pharmaceutical wastewater at a ratio of 1%. The pharmaceutical wastewater enters the reactor after anaerobically treated in an anaerobic water distribution tank, the mass ratio of C to N is 2.0, the dissolved oxygen concentration in the reactor is controlled to be 0.5 mg / L, the temperature is 28°C, and the organic carbon source in the wastewater is used to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen.

[0046] The technology of this embodiment is used to denitrify 1L of pharmaceutical wastewater (influent water quality: ammonia nitrogen 481.25mg / L, total nitrogen 542.11mg / L, COD 1084.00mg / L). Figure 3aIt can be seen that the reactor effluent contains only 37.30 mg NH 4 + -N / L, 13.30mg NO 2 - -N / L, 0.01mg NO 3 - -N / L, 50.60mg TN / L; at the same time Figure 3b As shown, NH 4 + The -N removal efficiency was 92.25%, the TN removal efficiency was 90.66%, and the SND efficiency was 88.23%.

[0047] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for deep denitrification of pharmaceutical wastewater based on a synchronous short-range nitrification and denitrification process, characterized in that: The steps include: 1) Pick out 2 loops of Ochrobacterium, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii, and Paracoccus denitrificans respectively, transfer them to the nutrient solution, culture them independently, inoculate them into the proliferation medium at a volume ratio of 5-15%, culture them independently, and centrifuge them to obtain the logarithmic growth phase cells of various bacteria respectively; 2) washing the cells in the logarithmic growth phase with phosphate buffer, and mixing 18-25% of Ochrobacterium sphaeroides, 14-18% of Stenotrophomonas maltophilia, 16-20% of Pseudomonas stutzeri, 20-25% of Citrobacter freundii and 17-27% of Paracoccus denitrificans in accordance with the volume ratio to obtain a SND bio-enhanced bacterial community for aerobic synchronous short-range nitrification and denitrification; 3) The SND bio-augmented bacterial flora was made into OD with sterile water. 600 A bacterial suspension with a concentration of 1.0 to 1.5 is inoculated into a reactor containing pharmaceutical wastewater at a ratio of 1 to 5%; the pharmaceutical wastewater is anaerobic treated in an anaerobic water distribution tank before entering the reactor, the dissolved oxygen concentration and temperature in the reactor are controlled, and the organic carbon source in the wastewater is used to achieve short-range synchronous removal of ammonia nitrogen and nitrate nitrogen; In step 1), the Ochrobactrum, Stenotrophomonas maltophilia, Pseudomonas stutzeri, Citrobacter freundii and Paracoccus denitrificans were purchased from Guangdong Microbiological Culture Collection Center, and their catalog numbers are: GDMCC 1.1609, GDMCC 1.552, GDMCC 1.1225, GDMCC 1.1031, GDMCC 1.335, respectively.

2. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 1), the culture conditions of the independent culture are: independent culture at 35-37° C. for 1-3 days.

3. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 1), the main components of the nutrient solution are: 10.0 g / L tryptone, 10.0 g / L NaCl, 5.0 g / L yeast extract powder, pH 6.8-7.2, and the rest is water.

4. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 1), the main components of the proliferation culture medium are: 20.0 g / L casein, 3.0 g / L potassium dihydrogen phosphate, 3.0 g / L glucose, 5.0 g / L sodium chloride, and the rest is water.

5. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 1), the centrifugal treatment is performed at 5000-8000 rpm for 3-5 min.

6. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 2), the main components of the phosphate buffer are: 8.0 g / L sodium chloride, 7.98 g / L dipotassium hydrogen phosphate trihydrate, 2.04 g / L potassium dihydrogen phosphate, and the rest is water.

7. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 2), the washing is performed 1 to 3 times.

8. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 3), the mass ratio of C to N in the pharmaceutical wastewater entering the reactor is 2.0-6.

0.

9. The method for deep denitrification of pharmaceutical wastewater based on synchronous short-range nitrification and denitrification process according to claim 1, characterized in that: In step 3), the dissolved oxygen concentration in the reactor is controlled at 0.5-1.5 mg / L, and the temperature is controlled at 28-32°C.

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