Domestic chemical wastewater treatment method

Abstract

The invention discloses a daily chemical wastewater treatment method which specifically comprises the following steps: S1, carrying out anaerobic microorganism decomposition on daily chemical wastewater to remove most pollutants in the daily chemical wastewater so as to obtain pretreated wastewater; s2, mixing the pretreated daily chemical wastewater with ozone to obtain wastewater dissolved with ozone; and S3, conveying the ozone-dissolved wastewater into an ozone biological activated carbon reactor (9), decomposing organic matters in the wastewater, precipitating and discharging. According to the invention, the biodegradability of the wastewater can be improved, the additional addition of chemicals can be realized, the generation of sludge is greatly reduced, and the operation cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of chemical wastewater treatment, and in particular to a method for treating daily chemical wastewater. Background Art

[0002] At present, the commonly used treatment methods for daily chemical wastewater are mainly the following: (1) The main treatment method adopts the "coagulation sedimentation + AAO + secondary sedimentation" process. The wastewater first reacts in the coagulation sedimentation by adding chemicals to remove some color and suspended solids, and then the decomposition of anaerobic and aerobic microorganisms removes most of the pollutants. Finally, the microorganisms are precipitated and the water is discharged; (2) The main treatment method adopts the "Fenton + coagulation sedimentation + AAO + secondary sedimentation" process. The wastewater first enters the Fenton reaction tank. Through the action of Fenton oxidation, some organic pollutants are reduced. By adding chemicals to react in the coagulation sedimentation, some color and suspended solids are removed. Then, through the decomposition of anaerobic and aerobic microorganisms, most of the pollutants in the wastewater are removed. Finally, the microorganisms are precipitated and the water is discharged. (3) The process of "Fenton + coagulation sedimentation + AAO + MBR" is mainly used for treatment. The wastewater first enters the Fenton reaction tank, and the addition of oxidants reduces some organic pollutants through the action of Fenton oxidation. The addition of chemicals reacts in the coagulation sedimentation to remove some chromaticity and suspended solids. The decomposition of anaerobic and aerobic microorganisms removes most of the pollutants in the wastewater. Finally, the water is filtered out through the MBR membrane. (4) The process of "Fenton + coagulation sedimentation + UASB + AO + MBR" is mainly used for treatment. On the basis of (3), UASB is used to replace the original anaerobic tank. The wastewater first enters the Fenton reaction tank, and the addition of oxidants reduces some organic pollutants through the action of Fenton oxidation. The addition of chemicals reacts in the coagulation sedimentation to remove some chromaticity and suspended solids. The decomposition of UASB and aerobic microorganisms removes most of the pollutants in the wastewater. Finally, the water is filtered out through the MBR membrane.

[0003] The four daily chemical wastewater treatment processes in the above-mentioned prior art all have shortcomings: In method 1, its main shortcomings are: a. A large amount of reagents need to be added during coagulation and sedimentation, resulting in an increase in the amount of sludge produced, and the cost of reagents and sludge treatment and disposal also increases accordingly; b. The biodegradability of this type of wastewater is poor, and no measures to improve biodegradability are set up at the front end. The removal rate of various pollutants using conventional AAO sewage treatment processes is low; c. The overall process has a low removal rate for various pollutants, and it is difficult to meet high emission standards.

[0004] (2) The main difference between Method 2 and Method 1 is that Method 2 has been partially improved by adding a Fenton treatment process before the coagulation sedimentation tank. Through Fenton oxidation, the color and organic matter in the wastewater can be effectively removed, the biodegradability of the wastewater can be improved, and the subsequent biochemical treatment effect can be improved. However, the Fenton treatment process requires a large amount of reagents to be added, the reaction conditions are strictly controlled, and the operation and maintenance are troublesome, which will further increase the amount of sludge treatment and disposal and the operating cost. It is difficult for enterprises to accept it. In addition, this method still cannot meet the high emission standards;

[0005] (3) Compared with method 2, method 3 has made another improvement to the process, using MBR filtered water instead of conventional secondary sedimentation water. This method can effectively increase the concentration of microorganisms in the biochemical treatment system, improve the water quality of the effluent, and reduce the land area. However, the MBR membrane has a short service life, is easy to clog, has high requirements for operators, and is more troublesome to operate and maintain. Therefore, in addition to adding a large amount of chemicals, this method also increases the operating cost of the MBR membrane, further increasing the cost of wastewater treatment.

[0006] (4) Compared with method 3, method 4 mainly uses UASB to replace the traditional anaerobic tank. This improvement can effectively improve the pollutant removal rate, reduce the project land area, and meet the high emission standards. However, this method still cannot solve the shortcomings of method 3.

[0007] Therefore, the present invention improves and proposes a method for treating daily chemical wastewater to solve the shortcomings of the prior art. Summary of the invention

[0008] The present invention aims to solve at least one of the problems in the related art to a certain extent. To this end, the purpose of the present invention is to provide a method for treating daily chemical wastewater, which can not only improve the biodegradability of wastewater, but also realize the addition of additional reagents, greatly reduce the amount of sludge generated and reduce the operating cost.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme: a method for treating daily chemical wastewater, comprising:

[0010] S1: Anaerobic microbial decomposition of daily chemical wastewater removes most of the pollutants in the daily chemical wastewater to obtain pretreated wastewater.

[0011] S2: After pretreatment, daily chemical wastewater is mixed with ozone to obtain wastewater dissolved with ozone.

[0012] S3: The wastewater dissolved with ozone is transported to the ozone biological activated carbon reactor 9 to decompose the organic matter in the wastewater and then precipitate and discharge it.

[0013] The daily chemical wastewater treatment method steps in the above steps S1-S3 need to be completed by a raw water barrel 1, a raw water pump 2, a UASB reactor 3, an anaerobic sedimentation tank 4, an intermediate tank 5, a dissolved air pump 6, a Churi ejector 7, a dissolved air tank 8, an ozone biological activated carbon reactor 9, an air compressor 10 and an ozone generator 11 being connected to form a wastewater treatment system.

[0014] Furthermore, the outlet of the raw water barrel 1 is connected to the UASB reactor 3 through a pipeline provided with a raw water pump 2, the outlet of the UASB reactor 3 is connected to the anaerobic sedimentation tank 4 through a pipeline, and the outlet of the anaerobic sedimentation tank 4 is connected to the intermediate tank 5 through a pipeline.

[0015] Furthermore, an anaerobic sludge return port is provided at the bottom of the anaerobic sedimentation tank 4 to return anaerobic sludge to the UASB reactor 3 through a pipeline.

[0016] Furthermore, the water outlet of the intermediate pool 5 is connected to the air dissolving tank (8) through a pipeline provided with an air dissolving pump 6, and a venturi ejector 7 is installed in front of the air dissolving pump 6. The venturi ejector 7 is connected to an ozone generator 11, and the ozone generator 11 is connected to an air compressor 10. The water outlet of the air dissolving tank 8 is connected to an ozone biological activated carbon reactor 9 through a pipeline.

[0017] Furthermore, the ozone biological activated carbon reactor 9 adopts a tower structure design, which is divided into two functional areas, the upper part is a precipitation area, and the lower part is a reaction area, wherein:

[0018] The reaction zone includes a releaser 901, which is connected to the ozone biological activated carbon reactor 9. A support layer 902 is provided at the upper end of the releaser 901, an activated carbon layer A903 is provided at the upper end of the support layer 902, an ozone catalyst layer 904 is provided at the upper end of the activated carbon layer A903, and an activated carbon layer 905 is provided at the end of the ozone catalyst layer 904;

[0019] The sedimentation area includes a guide tube 907, an overflow weir 908, an exhaust pipe 909, and a top mud discharge pipe 910. The overflow weir 908 is arranged above the sedimentation area, the guide tube 907 is arranged in the middle of the sedimentation area, the exhaust pipe 909 is arranged on both sides of the sedimentation area, and the top mud discharge pipe 910 is below the sedimentation area.

[0020] Furthermore, a bottom mud discharge pipe 906 is provided at the bottom of the reaction zone below the ozone biological activated carbon reactor 9 , and inspection holes 911 are provided on both sides of the ozone biological activated carbon reactor 9 .

[0021] Furthermore, a perforated aeration pipe 912 is provided between the releaser 901 and the supporting layer 902 , and the perforated aeration pipe 912 is connected to a blower 913 .

[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0023] (1) The problem of large dosage of chemical wastewater treatment agents in current daily use is solved. The present invention does not require additional dosage of chemical agents during use, greatly reducing the amount of sludge generated and the operating cost;

[0024] (2) Changing the way to improve the biodegradability of wastewater, replacing the Fenton oxidation process with ozone oxidation, can effectively improve the biodegradability of wastewater while reducing the requirements for operators;

[0025] (3) Changing the traditional AAO biochemical treatment process and adopting an ozone biofilter structure, the activated carbon with a large specific surface area can provide a large growth space for microorganisms, can carry more microorganisms, and effectively remove various pollutants in wastewater;

[0026] (4) Reduce the floor space. The present invention combines ozone oxidation, biochemical and precipitation processes into one, and adopts a tower structure, which can greatly reduce the floor space.

[0027] (5) To solve the problem of short service life and easy clogging of MBR membrane. The key ozone biochemical activated carbon technology of the present invention uses activated carbon as a carrier, which can be used for a long time without replacement and only requires regular backwashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0029] In the attached figure:

[0030] Figure 1 This is a flow chart of the method for treating daily chemical wastewater in this application;

[0031] Figure 2 This is a system diagram for wastewater treatment used in this application.

[0032] The above drawings include the following reference numerals:

[0033] 1. Raw water barrel; 2. Raw water pump; 3. UASB reactor; 4. Anaerobic sedimentation tank; 5. Intermediate tank; 6. Dissolved air pump; 7. Venturi tube; 8. Dissolved air tank; 9. Ozone biological activated carbon reactor; 10. Air compressor; 11. Ozone generator; 901. Releaser; 902. Support layer; 903. Activated carbon layer A; 904. Ozone catalyst layer; 905. Activated carbon layer; 906. Bottom mud discharge pipe; 907. Guide tube; 908. Overflow weir; 909. Exhaust pipe; 910. Top mud discharge pipe; 911. Inspection hole; 912. Perforated aeration pipe; 913. Blower. DETAILED DESCRIPTION

[0034] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Without departing from the spirit and essence of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention all belong to the scope of protection of the present invention. Unless otherwise specified, the experimental materials, reagents, instruments, etc. used in the present examples are all commercially available; unless otherwise specified, all technical means in the examples of the present invention are conventional means well known to those skilled in the art.

[0035] See also Figure 1 and Figure 2 The invention provides a technical solution: a method for treating daily chemical wastewater. The specific steps of the wastewater treatment method are as follows:

[0036] S1: Anaerobic microbial decomposition of daily chemical wastewater removes most of the pollutants in the daily chemical wastewater to obtain pretreated wastewater.

[0037] S2: After pretreatment, daily chemical wastewater is mixed with ozone to obtain wastewater dissolved with ozone.

[0038] S3: The wastewater dissolved with ozone is transported to the ozone biological activated carbon reactor (9) to decompose the organic matter in the wastewater and then precipitate it out.

[0039] The daily chemical wastewater treatment method steps in the above steps S1-S3 need to be completed by the raw water barrel (1), the raw water pump (2), the UASB reactor (3), the anaerobic sedimentation tank (4), the intermediate tank (5), the dissolved air pump (6), the Churi ejector (7), the dissolved air tank (8), the ozone biological activated carbon reactor (9), the air compressor (10) and the ozone generator (11) being connected to form a set of wastewater treatment system.

[0040] Specifically, in step S1, the daily chemical wastewater is first temporarily stored in a raw water barrel (1), and then lifted and transported to the UASB reactor (3) through a raw water pump (2) and a pipeline. The anaerobic sludge in the UASB reactor (3) contains a large number of anaerobic microorganisms, and most of the pollutants in the daily chemical wastewater can be removed through the decomposition action of the anaerobic microorganisms, thereby improving the biodegradability of the wastewater and reducing the subsequent treatment load.

[0041] The daily chemical wastewater enters the anaerobic sedimentation tank (4) from the outlet of the UASB reactor (3). The anaerobic sludge in the wastewater is precipitated to the bottom of the anaerobic sedimentation tank 4 by gravity sedimentation. At the bottom of the anaerobic sedimentation tank 4, a return pipe is provided to remove the precipitated anaerobic sludge and return it to the UASB reactor (3) to prevent the sludge from clogging the subsequent treatment system.

[0042] In step S2, the pretreated wastewater after precipitation in the anaerobic precipitation tank 4 of step S1 is transported to the intermediate tank (5) for temporary storage. While entering the next step of treatment, the air compressor 10 and the ozone generator 11 are operated to produce ozone, which is sucked into the Venturi ejector (7) arranged between the intermediate tank (5) and the dissolved air pump (6) and mixed with the wastewater. The ozone is then lifted and transported into the dissolved air tank (8) by the dissolved air pump (6); wherein the air source required by the ozone generator (11) is provided by the air compressor (10) to ensure that the working pressure meets the requirements; after the wastewater and ozone are mixed and enter the dissolved air tank (8), the ozone is fully dissolved into the wastewater under a certain pressure, thereby strengthening the contact between the ozone and the wastewater.

[0043] In step S3, the wastewater dissolved with ozone is transported into the ozone biological activated carbon reactor (9) and then released through the releaser (12). After the wastewater is released, the pressure suddenly decreases, and the ozone dissolved in the wastewater is released as extremely small bubbles, and then fully contacts and reacts with the wastewater. Through the strong oxidation effect of ozone, the organic matter in the wastewater is decomposed, and the color in the wastewater is removed, thereby improving the biodegradability of the wastewater.

[0044] Specifically, the present invention designs a tower-type biochemical treatment equipment in this key step, named as an ozone biological activated carbon reactor, which is divided into two functional areas, the upper part is a precipitation area, and the lower part is a reaction area, wherein the wastewater released in the reaction area passes through the support layer (13) upward and enters the activated carbon layer A (14), the ozone catalyst layer (904) and the activated carbon layer (905), the support layer (13) is made of crushed stone to prevent sludge from going upward, which can effectively reduce blockage, the activated carbon has a large specific surface area, and can provide a growth carrier for a large number of aerobic and facultative microorganisms, and the ozone catalyst can decompose excess ozone to prevent it from causing harm to the upper microorganisms. The decomposed ozone forms oxygen, which provides good conditions for the growth of microorganisms, and the ozone can be fully utilized.

[0045] A perforated aeration pipe (912) is also laid between the releaser (901) and the supporting layer (902), and the perforated aeration pipe (912) is connected to a blower (913). The blower (21) provides aeration for air washing of the ozone biological activated carbon reactor (9) to prevent it from being blocked.

[0046] The ozone biological activated carbon reactor (9) of the present application is located above the sedimentation zone. The wastewater after biochemical treatment contains a small amount of sludge, which can be directly discharged through the outlet after sedimentation in the sedimentation zone. The sedimentation zone is also provided with an overflow weir (18) to adjust the water level. A guide tube (17) is provided in the middle position to effectively buffer the release of water inlet energy, reduce the impact force on the bottom of the sedimentation zone, and reduce the impact of water inlet fluctuations on the sedimentation zone, thereby improving the sedimentation effect. The top mud discharge pipe (20) is located below, which can discharge mud regularly. Exhaust pipes (19) are provided on both sides to discharge the generated waste gas.

[0047] Finally, a bottom mud discharge pipe (906) is provided at the bottom of the ozone biological activated carbon reactor (9) of the present application, so that mud can be discharged regularly; and inspection holes are provided on both sides of the ozone biological activated carbon reactor (9) to facilitate daily observation and maintenance.

[0048] In summary, a daily chemical wastewater treatment method of the present application can effectively reduce the wastewater treatment cost without using chemicals, and adopts ozone oxidation process to replace Fenton oxidation process, which can not only reduce the amount of drugs added, but also greatly reduce the amount of sludge generated; secondly, adopting UASB+ozone activated carbon biofilter process to replace traditional AAO biochemical process can greatly reduce the floor space, because activated carbon has a large specific surface area, under the same volume, more microorganisms can survive, greatly improving the treatment efficiency; secondly, the ozone activated carbon biofilter of the present invention combines ozone oxidation, biochemical and precipitation processes into one, and adopts a tower structure, which can greatly improve the utilization rate of ozone. The lower layer ozone oxidizes organic matter, improves the biodegradability of wastewater, and is easy to be decomposed by microorganisms in the upper layer. The decomposed ozone becomes oxygen, providing good living conditions for the upper microorganisms. The structure is very reasonable, and a sedimentation area is set on the top. The sludge in the water and the sludge generated during the air washing process can be precipitated here, without the need to set up additional sedimentation tanks, thus reducing the land area; secondly, the venturi ejector + dissolved air pump + dissolved air tank + releaser process is used for aeration to replace the traditional microporous aeration method. This aeration method can convert ozone into extremely small bubbles, and the bubble diameter is much smaller than the bubble diameter of microporous aeration, which can allow ozone to fully contact with pollutants in the wastewater, thereby improving the pollution removal rate and ozone utilization rate; secondly, a perforated aeration pipe is added below the ozone biological activated carbon reactor. The aeration pipe is mainly used for air washing of the ozone biological activated carbon reactor. Regularly opening the device can effectively prevent equipment blockage, and the mud generated by air washing can be discharged through the top and bottom mud discharge pipes; finally, an ozone catalyst is added to the middle of the ozone biological activated carbon reactor. This practice serves as a safety device, which can effectively remove excess ozone, allow ozone to fully decompose into oxygen, and prevent ozone from toxic to the microorganisms in the upper layer.

[0049] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A method for treating daily chemical wastewater, characterized in that: The specific steps of wastewater treatment are as follows: S1: Decompose daily chemical wastewater with anaerobic microorganisms to remove most pollutants in the daily chemical wastewater and obtain pretreated wastewater; S2: The daily chemical wastewater after pretreatment is mixed with ozone to obtain wastewater dissolved with ozone; S3: The wastewater dissolved with ozone is transported to the ozone biological activated carbon reactor (9) to decompose the organic matter in the wastewater and then precipitate it out. The daily chemical wastewater treatment method steps in the above steps S1-S3 need to be completed by the raw water barrel (1), the raw water pump (2), the UASB reactor (3), the anaerobic sedimentation tank (4), the intermediate tank (5), the dissolved air pump (6), the Churi ejector (7), the dissolved air tank (8), the ozone biological activated carbon reactor (9), the air compressor (10) and the ozone generator (11) being connected to form a set of wastewater treatment system.

2. A method for treating daily chemical wastewater according to claim 1, characterized in that: The water outlet of the raw water barrel (1) is connected to the UASB reactor (3) via a pipeline provided with a raw water pump (2); the water outlet of the UASB reactor (3) is connected to the anaerobic sedimentation tank (4) via a pipeline; and the water outlet of the anaerobic sedimentation tank (4) is connected to the intermediate tank (5) via a pipeline.

3. A method for treating daily chemical wastewater according to claim 2, characterized in that: An anaerobic sludge return port is arranged at the bottom of the anaerobic sedimentation tank (4) to return anaerobic sludge to the UASB reactor (3) through a pipeline.

4. A method for treating daily chemical wastewater according to claim 1, characterized in that: The water outlet of the intermediate pool (5) is connected to the air dissolving tank (8) through a pipeline provided with an air dissolving pump (6), a venturi ejector (7) is installed in front of the air dissolving pump (6), the venturi ejector (7) is connected to an ozone generator (11), the ozone generator (11) is connected to an air compressor (10), and the water outlet of the air dissolving tank (8) is connected to an ozone biological activated carbon reactor (9) through a pipeline.

5. A method for treating daily chemical wastewater according to claim 4, characterized in that: The ozone biological activated carbon reactor (9) adopts a tower structure design, which is divided into two functional areas, the upper part is a precipitation area, and the lower part is a reaction area, wherein: The reaction zone comprises a releaser (901), the releaser (901) is connected to an ozone biological activated carbon reactor (9), a support layer (902) is arranged at the upper end of the releaser (901), an activated carbon layer A (903) is arranged at the upper end of the support layer (902), an ozone catalyst layer (904) is arranged at the upper end of the activated carbon layer A (903), and an activated carbon layer (905) is arranged at the end of the ozone catalyst layer (904); The sedimentation area includes a guide tube (907), an overflow weir (908), an exhaust pipe (909), and a top mud discharge pipe (910). The overflow weir (908) is arranged above the sedimentation area, the guide tube (907) is arranged in the middle of the sedimentation area, the exhaust pipe (909) is arranged on both sides of the sedimentation area, and the top mud discharge pipe (910) is below the sedimentation area.

6. A method for treating daily chemical wastewater according to claim 5, characterized in that: A bottom mud discharge pipe (906) is provided at the bottom of the reaction zone below the ozone biological activated carbon reactor (9), and inspection holes (911) are provided on both sides of the ozone biological activated carbon reactor (9).

7. A method for treating daily chemical wastewater according to claim 5, characterized in that: A perforated aeration pipe (912) is also provided between the releaser (901) and the supporting layer (902), and the perforated aeration pipe (912) is connected to a blower (913).

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