Device and method for enhancing biochemical efficiency of coking wastewater by action of weak ultrasonic waves on activated sludge

Abstract

The invention relates to a device and a method for enhancing the biochemical efficiency of coking wastewater by action of weak ultrasonic waves on activated sludge, and belongs to the field of water pollution treatment. The device comprises a water inlet barrel, a water outlet barrel, an activated sludge barrel, an SBR (Sequencing Batch Reactor), a weak ultrasonic system and a timing control device, the SBR reactor is provided with a water inlet and a water outlet, a stirrer is arranged in the SBR reactor, and an aeration disc is arranged at the bottom of the SBR reactor; the activated sludge barrel is connected with the SBR reactor through a sludge pump; the weak ultrasonic system comprises an ultrasonic generator and an ultrasonic vibration rod; the timing control device is a PLC timing control system. According to the method, the weak ultrasound is directly acted on the activated sludge, so that the coking wastewater treatment efficiency is improved, the aim of enhancing the biochemical treatment of the wastewater under the condition of high utilization rate of the weak ultrasound is fulfilled, and a theoretical basis is laid for improving the utilization efficiency of the weak ultrasound.

Description

Technical Field

[0001] The invention relates to the field of water pollution treatment, and in particular to a device and method for enhancing the biochemical efficiency of coking wastewater by using activated sludge under the action of weak ultrasonic waves. Background Art

[0002] Coking wastewater is industrial wastewater generated during the coal-to-coke production, coal gas purification, and chemical product refining processes. Its composition is complex and varied, and it is difficult to biodegrade. Its biodegradability is poor, making it considered one of the most difficult industrial wastewaters to treat. Coking wastewater has a complex composition, and its pollutants can be divided into inorganic and organic pollutants. Inorganic pollutants generally exist in the form of ammonium salts, while organic matter includes phenols, polycyclic aromatic hydrocarbons, and heterocyclic compounds containing nitrogen, oxygen, and sulfur. Coking wastewater also contains a large amount of difficult-to-degrade compounds and has poor biodegradability. The wastewater is highly toxic, containing highly toxic and carcinogenic substances that harm aquatic life and humans.

[0003] Ultrasound can improve the structure of sludge flocs and promote cell wall disruption to release enzymes. However, conventional high-intensity ultrasound can easily damage microbial activity and consumes a lot of energy. Weak ultrasound, without significantly damaging microorganisms, can enhance sludge metabolic activity and pollutant degradation rates, offering advantages in energy efficiency and high efficiency.

[0004] Currently, many biochemical processes are widely used in the treatment of coking wastewater. SBR, as a typical activated sludge process, can construct a weak ultrasound-coupled SBR reaction system. However, previous studies focused on the action of weak ultrasound on the activated sludge mixture, and the wastewater was subjected to the weak ultrasound effect, resulting in low utilization rate of weak ultrasound. Summary of the Invention

[0005] To address these issues, the present invention, focusing on a weak ultrasound-assisted activated sludge model, proposes a device and method for enhancing the biochemical efficiency of coking wastewater using weak ultrasound. This invention directly applies weak ultrasound to the activated sludge, not only improving the treatment efficiency of coking wastewater but also achieving the goal of enhancing wastewater biochemical treatment under conditions of high weak ultrasound utilization, laying a theoretical foundation for improving the utilization efficiency of weak ultrasound.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A device for enhancing the biochemical efficiency of coking wastewater by using weak ultrasonic waves to act on activated sludge, the device comprising a water inlet bucket, a water outlet bucket, an activated sludge bucket, an SBR reactor, a weak ultrasonic system and a timing control device;

[0008] The SBR reactor is provided with a water inlet and a water outlet, the water inlet bucket is connected to the water inlet via a water inlet peristaltic pump, and the water outlet bucket is connected to the water outlet via a water outlet valve;

[0009] The SBR reactor is provided with an agitator and an aeration plate at the bottom;

[0010] The activated sludge tank is connected to the SBR reactor via a sludge pump, and the activated sludge is input into the SBR reactor via the sludge pump to treat the coking wastewater in the SBR reactor;

[0011] The weak ultrasonic system includes an ultrasonic generator and an ultrasonic vibrator. The ultrasonic vibrator is placed in the activated sludge barrel to directly act on the activated sludge in the activated sludge barrel with weak ultrasonic waves.

[0012] The timing control device is a PLC timing control system, which can control the switching of the water inlet peristaltic pump, the aeration plate, the stirrer, and the water outlet valve.

[0013] Furthermore, the SBR reactor is fixed on a base, and the agitator is fixed in the SBR reactor via a bracket.

[0014] A method for enhancing the biochemical efficiency of coking wastewater by using activated sludge under weak ultrasonic action, the method comprising the following steps:

[0015] (1) Adding coking wastewater and activated sludge into the SBR reactor;

[0016] (2) The water inlet time is controlled by the timing control device. After the water inlet is completed, the aeration plate is controlled to work. After the aeration is completed, the stirrer is controlled to work. After the stirring is completed, the water is allowed to settle for a certain period of time, and the outlet valve is controlled to drain water.

[0017] (3) Turn off the timing control device, pump half of the activated sludge in the SBR reactor into the activated sludge barrel through the sludge pump, perform weak ultrasonic treatment on the activated sludge through the weak ultrasonic system, and then pump it back into the SBR reactor through the sludge pump after the end;

[0018] (4) Repeat the addition of coking wastewater and steps (2) to (4).

[0019] Furthermore, in step (1), the volume ratio of coking wastewater to activated sludge is 1-3:1.

[0020] Furthermore, in step (3), the power of weak ultrasound is 8-15 W / L, and the ultrasound is performed for 10-15 minutes.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The device of the present invention uses weak ultrasound to act on activated sludge to enhance the biochemical efficiency of coking wastewater. By setting an ultrasonic vibrator to directly act on the activated sludge after the effluent instead of acting on the mixture of coking wastewater, it emits weak ultrasonic waves during operation. On the one hand, it can improve the treatment efficiency of coking wastewater, and on the other hand, it can achieve the enhancement of wastewater biochemical treatment under the condition of high utilization rate of weak ultrasound.

[0023] 2. The present invention directly applies weak ultrasound to activated sludge, which can fully act on the activated sludge, slowing the growth rate of activated sludge concentration, increasing activated sludge enzyme activity, reducing the gaps between activated sludge flocs, increasing the specific surface area of ​​activated sludge flocs, and improving the permeability of activated sludge cell membranes. Compared with the blank group, the activated sludge directly treated with weak ultrasound reduced the growth of activated sludge by 16.3%. The activated sludge enzyme activities of ammonia monooxygenase, nitrosatase, nitrite reductase, nitrate reductase, and dehydrogenase increased by 0.1 U / g, 1.059 U / g, 104 umo / d / g, 6.8 umol / d / g, and 60 ug / d / g, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the device of the present invention.

[0025] In the figure, 1. bracket, 2. base, 3. aeration plate, 4. SBR reactor, 5. ultrasonic generator, 6. ultrasonic vibrator, 7. water outlet, 8. water outlet valve, 9. water outlet bucket, 10. water inlet bucket, 11. water inlet peristaltic pump, 12. water inlet, 13. agitator, 14. timing control device, 15. ultrasonic generator display, 16. ultrasonic generator power supply, 17. ultrasonic generator current adjustment button, 18. ultrasonic generator start and pause button, 19. sludge pump, 20. activated sludge barrel. DETAILED DESCRIPTION

[0026] The technical solutions and effects of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] Existing technologies often use biochemical processes to treat coking wastewater, combining them with ultrasound to act on a mixed activated sludge solution for a synergistic effect. However, in this coking wastewater treatment process, the wastewater takes on the role of weak ultrasound, resulting in less weak ultrasound energy reaching the activated sludge, leading to low utilization rates of both weak ultrasound and activated sludge.

[0028] The present invention finds that by directly acting weak ultrasound on activated sludge, then adding the activated sludge after weak ultrasound into coking wastewater and treating it with a biochemical process, the treatment efficiency of the coking wastewater is improved.

[0029] The technical solutions and effects of the present invention will be further illustrated below using examples and comparative examples.

[0030] Example 1

[0031] like Figure 1As shown, the device for enhancing the biochemical efficiency of coking wastewater by using weak ultrasonic waves to activate sludge of the present invention comprises a water inlet bucket 10, a water outlet bucket 9, an activated sludge bucket 20, an SBR reactor 4, a weak ultrasonic system and a timing control device 14;

[0032] The SBR reactor 4 is provided with a water inlet 12 and a water outlet 7, the water inlet bucket 10 is connected to the water inlet 12 via a water inlet peristaltic pump 11, and the water outlet bucket 9 is connected to the water outlet 7 via a water outlet valve 8;

[0033] The SBR reactor 4 is provided with a stirrer 13 and an aeration plate 3 at the bottom;

[0034] The activated sludge tank 20 is connected to the SBR reactor 4 via a sludge pump 19, and the activated sludge is input into the SBR reactor 4 via the sludge pump 19 to treat the coking wastewater in the SBR reactor 4;

[0035] The weak ultrasonic system includes an ultrasonic generator 5 and an ultrasonic vibrator 6. The ultrasonic vibrator 6 is placed in the activated sludge barrel 20 to directly act on the activated sludge in the activated sludge barrel 20 with weak ultrasonic waves.

[0036] The timing control device 14 is a PLC timing control system, which can control the switching of the water inlet peristaltic pump 11, the aeration plate 3, the stirrer 13, and the water outlet valve 8. The specific connection relationship is the existing technology and will not be repeated here.

[0037] In this embodiment, the SBR reactor 4 is fixed on the base 2 , and the agitator 13 is fixed in the SBR reactor 4 via the bracket 1 .

[0038] As a specific embodiment, the SBR reactor 4 is a non-sealed cylindrical reactor made of organic glass.

[0039] As a specific embodiment, the ultrasonic generator 5 is provided with an ultrasonic generator display screen 15, an ultrasonic generator power supply 16, an ultrasonic generator current adjustment button 17, and an ultrasonic generator start and pause button 18, which are used to operate the ultrasonic generator 5. The ultrasonic generator 5 adjusts the output current size to adjust the sound energy density of the ultrasonic vibrator irradiated ultrasound, and at the same time adjusts the duration and mode.

[0040] The working principle of the device is as follows: after the effluent stage, weak ultrasound acts directly on the activated sludge. Through mechanical vibration, weak ultrasound improves the sludge floc structure, promotes cell wall rupture and releases intracellular enzymes; enhances microbial metabolic activity, accelerates the decomposition of difficult-to-degrade organic matter such as polycyclic aromatic hydrocarbons; avoids the damage of traditional high-intensity ultrasound to microorganisms, and at the same time improves the utilization rate of ultrasonic energy.

[0041] The present invention also provides a method for enhancing the biochemical efficiency of coking wastewater by using the above device through the action of weak ultrasonic waves on activated sludge, comprising the following steps:

[0042] (1) Adding coking wastewater and activated sludge into the SBR reactor;

[0043] (2) The water inlet time is controlled by the timing control device. After the water inlet is completed, the aeration plate is controlled to work. After the aeration is completed, the stirrer is controlled to work. After the stirring is completed, the water is allowed to settle for a certain period of time, and the outlet valve is controlled to drain water.

[0044] (3) Turn off the timing control device, pump half of the activated sludge in the SBR reactor into the activated sludge barrel through the sludge pump, perform weak ultrasonic treatment on the activated sludge through the weak ultrasonic system, and then pump it back into the SBR reactor through the sludge pump after the end;

[0045] (4) Repeat the addition of coking wastewater and steps (2) to (4).

[0046] In this embodiment, the activated sludge added in step (1) is activated sludge treated with weak ultrasound.

[0047] In this embodiment, the volume ratio of coking wastewater to activated sludge is 1-3:1.

[0048] In this embodiment, the power of weak ultrasound is 8-15 W / L, the ultrasound is performed for 10-15 minutes, and the ultrasound frequency can be selected to be 40 kHz.

[0049] Half of the sludge was taken out for weak ultrasound because the experiment explored the amount of sludge acted on by weak ultrasound at 1, 1 / 2, 1 / 3 and 1 / 4 of the total amount of activated sludge respectively; when the amount of the total amount of sludge was explored, because the amount of activated sludge acted on was too much, the ultrasonic energy would be dispersed in a large amount in more activated sludge particles and water bodies, resulting in a decrease in the ultrasonic energy density received by the activated sludge per unit volume; and when the amount of sludge acted on was 1 / 3 and 1 / 4, because the amount of activated sludge acted on by ultrasound was too small, the synergistic effect between the activated sludge particles and with other components was difficult to effectively exert, resulting in a higher effluent concentration.

[0050] Therefore, considering the water quality treatment effect and other indicators, the optimal parameter is 1 / 2 of the total amount of activated sludge under weak ultrasonic treatment.

[0051] As a specific embodiment, a method for enhancing the biochemical efficiency of coking wastewater by using activated sludge with weak ultrasound comprises the following steps:

[0052] 3 L of coking wastewater and 2 L of activated sludge were added to the SBR reactor;

[0053] Turn on the timing control device, the timing time is water inlet 10 minutes, aeration 6 hours, stirring 4 hours, sedimentation and standing 100 minutes, water discharge 10 minutes; that is, water is inlet from the water inlet for 10 minutes, then the aeration plate works for 6 hours, after the aeration is completed, the stirrer works for 4 hours, after the stirring is completed, it is stood for 100 minutes, and after the standing is completed, water is discharged from the water outlet 7 for 10 minutes.

[0054] Turn off the timing control device, use the sewage pump to pump out half of the activated sludge into the activated sludge barrel, place the ultrasonic vibrator into the activated sludge barrel, start the ultrasonic generator, adjust the current to 0.1A, that is, the power density is 11W / L, ultrasonicate for 10 minutes, then re-introduce the activated sludge into the SBR reactor and continue the above operations.

[0055] The coking wastewater and activated sludge used in the experiment were collected from a coking plant in Pingdingshan City, Henan Province. The influent COD concentration was 662 mg / L, the influent phenol concentration was 113.2 mg / L, and the influent nitrate nitrogen concentration was 1.7 mg / L.

[0056] Comparative Example 1

[0057] The method for enhancing the biochemical efficiency of coking wastewater by using activated sludge with weak ultrasonic wave in this comparative example is to directly add the activated sludge into the SBR reactor and perform weak ultrasonic wave on the mixed liquid in the SBR reactor. The power density of each weak ultrasonic wave is 11W / L and the ultrasonic wave lasts for 10 minutes.

[0058] Comparative Example 2

[0059] The method of enhancing the biochemical efficiency of coking wastewater by using activated sludge under weak ultrasonic treatment in this comparative example is to directly add the activated sludge into the SBR reactor without applying weak ultrasonic treatment.

[0060] After two cycles, the effluent quality of Example 1, Comparative Example 1 and Comparative Example 2 were:

[0061] Example 1: The effluent COD concentration is 109.8 mg / L, the effluent phenol concentration is 1.57 mg / L, and the effluent nitrate nitrogen concentration is 0.67 mg / L;

[0062] Comparative Example 1: The effluent COD concentration was 113.8 mg / L, the effluent phenol concentration was 4.2 mg / L, and the effluent nitrate nitrogen concentration was 0.71 mg / L;

[0063] Comparative Example 2: The effluent COD concentration was 118 mg / L, the effluent phenol concentration was 6.8 mg / L, and the effluent nitrate nitrogen concentration was 0.76 mg / L.

[0064] The removal rates of COD, phenol and nitrate nitrogen are shown in Table 1.

[0065] Table 1 Removal rates of COD, phenol and nitrate nitrogen

[0066]

[0067] In summary, the ultrasonic vibrator provided an ultrasonic power density of 11 W / L and an ultrasonic time of 10 min, which promoted the secretion of activated sludge enzymes and the improvement of enzyme activity in the reaction system, and improved the utilization rate of weak ultrasound while promoting the dispersion of objects in the liquid phase.

[0068] The activated sludge enzyme activities of ammonia monooxygenase, nitrosatase, nitrite reductase, nitrate reductase and dehydrogenase increased by 0.1 U / g, 1.059 U / g, 104 umo / d / g, 6.8 umol / d / g and 60 ug / d / g respectively compared with the blank group.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A device for enhancing the biochemical efficiency of coking wastewater by using weak ultrasonic waves to activate sludge, characterized in that: The device includes a water inlet bucket, a water outlet bucket, an activated sludge bucket, an SBR reactor, a weak ultrasonic system and a timing control device; The SBR reactor is provided with a water inlet and a water outlet, the water inlet bucket is connected to the water inlet via a water inlet peristaltic pump, and the water outlet bucket is connected to the water outlet via a water outlet valve; The SBR reactor is provided with an agitator and an aeration plate at the bottom; The activated sludge tank is connected to the SBR reactor via a sludge pump, and the activated sludge is input into the SBR reactor via the sludge pump to treat the coking wastewater in the SBR reactor; The weak ultrasonic system includes an ultrasonic generator and an ultrasonic vibrator. The ultrasonic vibrator is placed in the activated sludge barrel to directly act on the activated sludge in the activated sludge barrel with weak ultrasonic waves. The timing control device is a PLC timing control system, which can control the switching of the water inlet peristaltic pump, the aeration plate, the stirrer, and the water outlet valve.

2. The device for enhancing the biochemical efficiency of coking wastewater by using activated sludge under weak ultrasonic action according to claim 1 is characterized in that: The SBR reactor is fixed on a base, and the agitator is fixed in the SBR reactor through a bracket.

3. A method for enhancing the biochemical efficiency of coking wastewater by using weak ultrasonic wave to activate sludge, characterized in that: The method comprises the following steps: (1) Adding coking wastewater and activated sludge into the SBR reactor; (2) The water inlet time is controlled by the timing control device. After the water inlet is completed, the aeration plate is controlled to work. After the aeration is completed, the stirrer is controlled to work. After the stirring is completed, the water is allowed to settle for a certain period of time, and the outlet valve is controlled to drain water. (3) Turn off the timing control device, pump half of the activated sludge in the SBR reactor into the activated sludge barrel through the sludge pump, perform weak ultrasonic treatment on the activated sludge through the weak ultrasonic system, and then pump it back into the SBR reactor through the sludge pump after the end; (4) Repeat the addition of coking wastewater and steps (2) to (4).

4. The method for enhancing the biochemical efficiency of coking wastewater by using activated sludge with weak ultrasonic waves according to claim 3, characterized in that: In the step (1), the volume ratio of coking wastewater to activated sludge is 1-3:

1.

5. The method for enhancing the biochemical efficiency of coking wastewater by using activated sludge with weak ultrasonic waves according to claim 3, characterized in that: In the step (3), the power of weak ultrasound is 8-15 W / L, and the ultrasound is performed for 10-15 minutes.

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