Method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing

Abstract

The invention relates to a method for realizing advanced nitrogen removal of high-salinity petrochemical wastewater by enhancing microbial population sensing, belongs to the technical field of biological treatment of high-salinity industrial wastewater, and aims at the problem of poor nitrogen removal efficiency of the high-salinity petrochemical wastewater by constructing a sulfur autotrophic denitrification deep-bed filter tank. The signal molecule dosing system is respectively connected with a water quality on-line monitoring module, a signal molecule pressurization system and a water inlet pump, a static mixer is arranged between the signal molecule dosing system and the sulfur autotrophic denitrification deep bed filter device, and a salinity on-line monitoring module is arranged between the water inlet pump and the sulfur autotrophic denitrification deep bed filter device; according to the present invention, the sulfur autotrophic denitrification deep bed filtration tank device is constructed, common activated sludge is inoculated, and the addition amount of the quorum sensing signal molecules is regulated and controlled by monitoring the salinity in real time so as to achieve efficient deep denitrification; the efficient deep denitrification of the high-salinity petrochemical wastewater is effectively realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological treatment of high-salt industrial wastewater, and particularly relates to a method for enhancing microbial quorum sensing to achieve deep denitrification of high-salt petrochemical wastewater. Background Art

[0002] Wastewater generated during the processing of the petrochemical industry generally contains 3%-8% sodium chloride (equivalent to a conductivity of 30-80 mS / cm), and at the same time contains toxic substances such as benzene series and sulfides, featuring high salinity, a large number of complex and difficult-to-degrade organic matters, and a low C / N ratio.

[0003] Currently, methods commonly used for the advanced treatment of petrochemical wastewater include membrane separation methods (reverse osmosis / electrodialysis), advanced oxidation methods (Fenton / ozone), and biological treatment, etc. Although membrane separation technology can remove salts, it has serious membrane fouling and difficult-to-treat concentrated liquid problems. Advanced oxidation technology can achieve the removal of difficult-to-degrade organic matters, but the removal efficiency of total nitrogen is low. Biological treatment technology can effectively achieve deep denitrification of sewage. However, under the osmotic pressure stress caused by salinity, problems such as dehydration and inactivation of microbial cells, a decrease in the rate of key enzymatic reactions, and obstruction of the electron transport chain are likely to occur, resulting in a decline in the denitrification performance of the system. Therefore, how to achieve efficient deep denitrification of petrochemical wastewater is an urgent problem to be solved at present.

[0004] Microbial quorum sensing is a communication mechanism by which microorganisms secrete and sense specific signal molecules to dynamically regulate group behavior. When the concentration of signal molecules reaches a threshold value, it triggers a cascade of gene expression reactions to coordinate group behaviors such as biofilm formation, secretion of toxic factors, and metabolic regulation. Existing research has found that a high-salt environment destroys the expression of LuxI / LuxR proteins, resulting in a 60%-80% decrease in the activity of signal molecule synthase. In addition, salt ions interfere with molecular diffusion. Based on this, the present invention realizes efficient denitrification of high-salt petrochemical wastewater by enhancing microbial quorum sensing. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention proposes a method for enhancing microbial quorum sensing to achieve deep denitrification of high-salt petrochemical wastewater, which can effectively and efficiently remove nitrate nitrogen in high-salt petrochemical wastewater, and has the advantages of good activity enhancement effect, high denitrification efficiency, low operating cost, no secondary pollution, etc. It is particularly suitable for the deep denitrification treatment of petrochemical wastewater with a salinity greater than 3%, and solves problems such as low denitrification efficiency caused by high-salt inhibition of microbial activity and the need for additional carbon source addition in traditional processes.

[0006] The present invention adopts the following technical solutions to solve the above problems:

[0007] A method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing. According to the influent salinity monitored in real time, the activity of denitrifying bacteria is enhanced by exogenous addition of quorum sensing signal molecules to achieve efficient deep denitrification. The specific steps are as follows:

[0008] S1: Construct a deep denitrification system, set up a sulfur autotrophic denitrification deep bed filter device, load fillers inside, and use pebbles to support the bottom of the fillers;

[0009] S2: Add traditional activated sludge to the sulfur autotrophic denitrification deep bed filter system, carry out internal circulation domestication, and cultivate the system flora;

[0010] S3: Keep the sulfur autotrophic denitrification deep bed filter in continuous operation until the sulfur autotrophic denitrification deep bed filter system is domesticated;

[0011] S4: Install a salinity on-line monitoring system at the influent. By adjusting the salinity on-line monitoring system, ensure the accuracy of the salinity on-line monitoring system;

[0012] S5: Regulate the signal molecule dosing device, and automatically adjust the dosing amount of signal molecules according to the influent salinity;

[0013] S6: After the system is debugged, connect the influent to the effluent of the secondary sedimentation tank. By detecting the influent salinity, timely add exogenous quorum sensing signal molecules to ensure efficient and stable denitrification of the sulfur autotrophic denitrification system.

[0014] Further, in S1, the sulfur autotrophic denitrification deep bed filter device is respectively connected with a water quality on-line monitoring module, a signal molecule pressurization system and a feed pump. A static mixer is provided between the signal molecule dosing system and the sulfur autotrophic denitrification deep bed filter device. A salinity on-line monitoring module is provided between the feed pump and the sulfur autotrophic denitrification deep bed filter device. The sulfur autotrophic denitrification deep bed filter device is also provided with a drainage well.

[0015] Further, in S1, the main body of the sulfur autotrophic denitrification deep bed filter device is 3 m high, the filler area is 1.5 m high, the backwashing area is 1.0 m high, the overflow area is 0.5 m high, and the filler height is 1.5 m.

[0016] Further, in S1, the filler uses pyrite particles with a particle size of 6 - 8 mm.

[0017] Further, in S2, when culturing the system flora, the influent nitrate nitrogen concentration is 50 mg / L, and the internal circulation domestication is carried out for 144 h, and nitrate nitrogen is supplemented every 24 h.

[0018] Further, in S3, the sign of successful domestication is that the total nitrogen in the effluent is lower than 10 mg / L.

[0019] Further, in S5, when the salinity is lower than 1%, the dosage of the signaling molecule is 1 μM, and when the salinity is higher than 1%, the dosage of the signaling molecule is 2 μM.

[0020] Further, in S6, the type of the quorum sensing signaling molecule is C6-HSL among acyl-homoserine lactone (AHL) signaling molecules. Under high salinity conditions, after the denitrification performance of the sulfur autotrophic denitrification deep bed filter is enhanced by the quorum sensing signaling molecule, the total nitrogen in the effluent can be lower than 15 mg / L.

[0021] Advantages of the present invention:

[0022] 1. The method of the present invention can effectively and efficiently remove nitrate nitrogen in petrochemical high-salt wastewater, and has the advantages of good activity enhancement effect, high denitrification efficiency, low operating cost, no secondary pollution, etc.

[0023] 2. The sulfur autotrophic denitrification deep bed filter device constructed in the present invention uniformly inoculates activated sludge in the deep bed filter in the form of suspended bacteria, and promotes its attachment and reproduction by means of circulating flow.

[0024] 3. According to the salinity detected by the on-line monitoring system, the denitrification performance of the sulfur autotrophic denitrification system is enhanced by externally adding quorum sensing signaling molecules.

[0025] 4. By strengthening the quorum sensing effect of microorganisms, the denitrification performance of the sulfur autotrophic denitrification deep bed filter is further enhanced.

[0026] 5. The method of the present invention can achieve a total nitrogen removal rate higher than 90% without externally adding a carbon source, while reducing the aeration energy consumption by more than 40%, and has strong resistance to salinity fluctuations, and is suitable for green and low-cost deep denitrification treatment of high-salt petrochemical wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The exemplary embodiments of the present invention will be described in more detail in conjunction with the accompanying drawings, making the above-mentioned objects, features and advantages of the present invention more obvious. In the exemplary embodiments of the present invention, the same reference numerals generally denote the same components.

[0028] Figure 1 It is a schematic connection structure diagram of the system;

[0029] Figure 2 It is a flow chart of the method. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The specific embodiments of the present invention will be described below to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, various changes are obvious within the spirit and scope of the present invention defined and determined by the appended claims. All inventions and creations using the concept of the present invention are within the scope of protection.

[0031] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the following embodiments of the present invention can be obtained through market purchases or prepared by existing methods.

[0032] As Figure 1 shown, the present invention first constructs a deep denitrification system. The autotrophic sulfur denitrification deep bed filter device is respectively connected with a water quality on-line monitoring module, a signal molecule pressurization system, and a feed pump. A static mixer is provided between the signal molecule dosing system and the autotrophic sulfur denitrification deep bed filter device. A salinity on-line monitoring module is provided between the feed pump and the autotrophic sulfur denitrification deep bed filter device. The autotrophic sulfur denitrification deep bed filter device is also provided with a drainage well.

[0033] The activated sludge is evenly inoculated into the deep bed filter in the form of suspended bacteria, and its attachment and reproduction are promoted by means of circulating flow. Subsequently, according to the salinity detected by the on-line monitoring system, the denitrification performance of the autotrophic sulfur denitrification system is enhanced by externally adding quorum sensing signal molecules. The quorum sensing signal molecule selected is C6-HSL among acyl-homoserine lactone (AHL) signal molecules. When the salinity is lower than 1%, the dosing amount is 1 μM. When the salinity is higher than 1%, the dosing amount is 2 μM. According to the real-time monitored influent salinity, the activity of denitrifying bacteria is enhanced by externally adding quorum sensing signal molecules to achieve efficient deep denitrification.

[0034] The above steps are described in detail below in conjunction with embodiments:

[0035] Embodiment 1

[0036] As Figure 2 shown, the method includes the following steps:

[0037] S1: Construct an autotrophic sulfur denitrification deep bed filter device, the main body of which is 3 m high, and a packing area (1.5 m), a backwashing area (1.0 m), and an overflow area (0.5 m) are set. The packing height is 1.5 m, and the packing is made of pyrite particles (particle size 6 - 8 mm), and pebbles are used to support the packing;

[0038] S2: Add traditional activated sludge to the autotrophic sulfur denitrification deep bed filter system. The influent nitrate nitrogen concentration is 50 mg / L. Carry out internal circulation domestication for 144 h, supplement nitrate nitrogen every 24 h, and cultivate the system flora.

[0039] S3: After the internal circulation operation mode in the second step, the autotrophic sulfur denitrification deep bed filter keeps running continuously until the total nitrogen in the effluent is lower than 10 mg / L, proving that the domestication of the autotrophic sulfur denitrification deep bed filter system is completed.

[0040] S4: Adjust the salinity on-line monitoring system to ensure its accuracy.

[0041] S5: Regulate the signal molecule dosing device, and automatically adjust the dosing amount of signal molecules according to the influent salinity. That is, when the salinity is lower than 1%, the dosing amount is 1 μM; when the salinity is higher than 1%, the dosing amount is 2 μM.

[0042] S6: After the system commissioning is completed, connect the influent to the effluent of the secondary sedimentation tank. By detecting the influent salinity, add the quorum sensing signal molecules in a timely manner to ensure the efficient and stable nitrogen removal of the autotrophic sulfur denitrification system.

[0043] Example 2

[0044] As the best embodiment of the present invention, the high-salt wastewater of a petrochemical enterprise in a coastal area contains a large amount of refractory organic matter and a high salt content after secondary biochemical treatment, and the total nitrogen is difficult to meet the national discharge standard. The water quality is as follows: the TOC value is 30 - 50 mg / L, the COD value is 70 - 90 mg / L, the TN value is 30 - 40 mg / L, and the salinity is 1% - 2%.

[0045] On the 1st - 10th days, the salinity on-line monitoring module monitors that the influent salinity is higher than 1%. When the signal molecule dosing pump of the system is not turned on, the total nitrogen in the effluent is generally higher than 20 mg / L, and the nitrogen removal performance of the autotrophic sulfur denitrification system is poor.

[0046] On the 11th - 20th days, the salinity on-line monitoring module monitors that the influent salinity is higher than 1%, and the signal molecule dosing pump is automatically turned on with a dosing amount of 2 μM. On the 15th day of the autotrophic sulfur denitrification system, the detected total nitrogen in the effluent is lower than 15 mg / L, indicating that the exogenous signal molecules effectively enhance the nitrogen removal performance of the system.

[0047] The present invention has been described in detail through examples above, but the content is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: According to the influent salinity monitored in real time, the activity of denitrifying bacteria is enhanced by externally adding quorum sensing signal molecules to achieve efficient and deep nitrogen removal. The specific steps are as follows: S1: Construct a deep nitrogen removal system, set up a sulfur autotrophic denitrification deep bed filter device, load fillers inside, and use pebbles to support the bottom of the fillers; S2: Add traditional activated sludge to the sulfur autotrophic denitrification deep bed filter system, carry out internal circulation domestication, and cultivate the system flora; S3: Keep the sulfur autotrophic denitrification deep bed filter in a continuous operation state until the sulfur autotrophic denitrification deep bed filter system is domesticated; S4: Install a salinity online monitoring system for the influent. By adjusting the salinity online monitoring system, ensure the accuracy of the salinity online monitoring system; S5: Regulate the signal molecule dosing device, and automatically adjust the dosing amount of signal molecules according to the influent salinity; S6: After the system is debugged, connect the influent to the effluent of the secondary sedimentation tank. By detecting the influent salinity, externally add quorum sensing signal molecules in a timely manner to ensure efficient and stable nitrogen removal in the sulfur autotrophic denitrification system.

2. The method for deeply denitrifying high-salinity petrochemical wastewater by enhancing microbial quorum sensing according to claim 1, characterized in that: In S1, the sulfur autotrophic denitrification deep bed filter device is respectively connected with a water quality online monitoring module, a signal molecule pressurization system and a feed pump. A static mixer is provided between the signal molecule dosing system and the sulfur autotrophic denitrification deep bed filter device. A salinity online monitoring module is provided between the feed pump and the sulfur autotrophic denitrification deep bed filter device. The sulfur autotrophic denitrification deep bed filter device is also provided with a drainage well.

3. A method for deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing according to claim 1, characterized in that: In S1, the main body of the sulfur autotrophic denitrification deep bed filter device is 3m high, the filler area is 1.5m high, the backwashing area is 1.0m high, the overflow area is 0.5m high, and the filler height is 1.5m.

4. A method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: In S1, the filler uses pyrite particles with a particle size of 6 - 8mm.

5. A method for deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: In S2, when cultivating the system flora, the influent nitrate nitrogen concentration is 50mg / L, the internal circulation domestication is 144h, and nitrate nitrogen is supplemented every 24h.

6. A method for achieving deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: In S3, the sign of successful domestication is that the total nitrogen in the effluent is lower than 10mg / L.

7. A method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: In S5, when the salinity is lower than 1%, the dosing amount of the signal molecule is 1μM, and when the salinity is higher than 1%, the dosing amount of the signal molecule is 2μM.

8. A method for realizing deep denitrification of high-salinity petrochemical wastewater by enhancing microbial quorum sensing, characterized in that: In S6, the type of the quorum sensing signal molecule is C6 - HSL in acyl - homoserine lactone (AHL) - type signal molecules. Under high - salinity conditions, after the nitrogen removal performance of the sulfur autotrophic denitrification deep bed filter is enhanced by the quorum sensing signal molecule, the total nitrogen in the effluent can be lower than 15mg / L.

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