Wastewater treatment method

Abstract

A wastewater treatment method, comprising: carrying out heat treatment on honeycomb stone under the action of ferric sulfate, urea and deionized water, and carrying out annealing treatment to obtain iron oxide nano-modified honeycomb stone; carrying out ozone oxidation pretreatment on wastewater, and then adjusting the pH value to 6.8-7.2; and inoculating sludge in an up-flow anaerobic sludge blanket (UASB) reactor and adding the iron oxide nano-modified honeycomb stone to process the wastewater. By establishing a UASB process based on synergistic enhancement of ozone and iron oxide nano-modified honeycomb stone, the starting time is shortened by 18 days compared with a common UASB reactor, the maximum organic load which can be borne is 2-4 times that of a common UASB reactor, and the average daily methane yield is increased by 10%-30%.

Description

Wastewater treatment method Technical Field

[0001] The present application belongs to the technical field of high-concentration organic wastewater treatment, and in particular relates to a method for optimizing UASB anaerobic process by using ozone and nano-iron oxide modified honeycomb stone. Background Art

[0002] Anaerobic biological treatment technology is one of the most commonly used methods for treating landfill leachate. Anaerobic biological treatment technology mainly involves microorganisms breaking down macromolecular organic matter such as proteins, polysaccharides, and fats into organic acids in an oxygen-free environment, and further converting them into CH4 and CO2. Upflow anaerobic sludge blanket (UASB) is widely used in the field of high-concentration organic wastewater due to its low operating costs and ability to maintain high biomass and rich microbial diversity. However, UASB reactors also have problems such as poor load shock resistance, easy acidification, and unstable operation. At the same time, landfill incineration leachate contains a large amount of difficult-to-degrade substances, high concentrations of ammonia nitrogen, volatile fatty acids, metal ions, and toxic compounds, which will have a certain inhibitory effect on anaerobic microorganisms, thereby affecting the stable operation of the anaerobic reactor and reducing the efficiency of anaerobic digestion.

[0003] Studies have found that carrier materials such as zeolite and activated carbon have the characteristics of good adsorption performance, porosity, and large specific surface area. While adsorbing pollutants in water, they can also fix microorganisms on the surface of the carrier, promote microorganisms to secrete more extracellular polymers, and accelerate the formation of anaerobic granular sludge, thereby improving anaerobic digestion efficiency and microbial activity. In addition, some conductive materials such as carbon cloth, magnetite, activated carbon, etc. can stimulate direct interspecies electron transfer (DIET) of microorganisms, which can effectively solve the problem that traditional anaerobic metabolism is too dependent on hydrogen partial pressure. Lei et al. added carbon cloth to the UASB reactor to treat incineration leachate. After adding carbon cloth, the reactor was able to achieve an OLR (influent organic load) of 49.4 kgCOD / (m 3 d) Stable operation.

[0004] However, the current UASB process still has problems such as low anaerobic digestion efficiency and poor load shock resistance, which need further improvement.

[0005] Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a wastewater treatment method, aiming to solve the problems of low anaerobic digestion efficiency and poor load impact resistance in the current UASB process.

[0007] The embodiment of the present application is implemented as follows: a wastewater treatment method, characterized by comprising:

[0008] The honeycomb stone is heated in the presence of ferric sulfate, urea and deionized water, and then annealed to obtain iron oxide nano-modified honeycomb stone.

[0009] After pre-treatment of wastewater with ozone oxidation, the pH value was adjusted to 6.8-7.2;

[0010] The wastewater is treated by inoculating sludge in an upflow anaerobic sludge blanket reactor and adding the iron oxide nano-modified honeycomb stone.

[0011] Optionally, the honeycomb stone is subjected to a heating treatment under the action of ferric sulfate, urea and deionized water, and then subjected to an annealing treatment to obtain the iron oxide nano-modified honeycomb stone, comprising:

[0012] The honeycomb stone is placed in ferric sulfate, urea and deionized water, mixed evenly and then heated at 100°C for 12 hours. After cooling and washing the precipitate, the obtained precursor is annealed at 600°C for 4 hours to obtain iron oxide nano-modified honeycomb stone.

[0013] Optionally, the honeycomb stone is subjected to a heating treatment under the action of ferric sulfate, urea and deionized water, and then subjected to an annealing treatment to obtain the iron oxide nano-modified honeycomb stone, comprising:

[0014] 10 g of honeycomb stone was weighed and placed in a conical flask, 20.0 g of ferric sulfate, 12.0 g of urea and 50 mL of deionized water were added to a beaker, and the mixture was stirred and dissolved on a magnetic stirrer for 10 minutes; the solution was transferred to the conical flask, the conical flask was sealed and placed in an oven, heated at 100° C. for 12 hours, and then naturally cooled to room temperature; the precipitate was collected and washed with deionized water; finally, the precursor was annealed at 600° C. for 4 hours to obtain iron oxide nano-modified honeycomb stone.

[0015] Optionally, the process of inoculating sludge in an upflow anaerobic sludge blanket reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater includes a startup phase and a load shock phase;

[0016] The startup phase includes operating conditions 1, 2 and 3, each lasting 20 days. Operating condition 1 corresponds to the 1st to 20th day, with a hydraulic retention time of 22±0.2h; operating condition 2 corresponds to the 21st to 40th day, with a hydraulic retention time of 20.5±0.2h; operating condition 3 corresponds to the 41st to 60th day, with a hydraulic retention time of 19±0.2h. By the end of the startup phase, the influent organic load is increased to 6-10kgCOD / (m 3 d) or above;

[0017] The load shock stage includes operating conditions 4, 5 and 6; operating condition 4 corresponds to the 61st to 90th day, the hydraulic retention time is 18±0.2h, and the influent organic load is increased to 24kgCOD / (m 3 ·d); Operating condition 5 corresponds to the 91st to 130th day, the hydraulic retention time is 16±0.2h, and the influent organic load is increased to 37kgCOD / (m 3 ·d) and then dropped to 15kgCOD / (m 3 ·d); Operating condition 6 corresponds to the 131st-165th day, the hydraulic retention time is 14.5±0.2h, and the influent organic load is increased to 70kgCOD / (m 3 ·d).

[0018] Optionally, in the step of inoculating sludge in an upflow anaerobic sludge blanket reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater, the particle size of the iron oxide nano-modified honeycomb stone is 1.00 mm to 3.00 mm.

[0019] Optionally, in the step of inoculating sludge in an upflow anaerobic sludge blanket reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater, the amount of the iron oxide nano-modified honeycomb stone added accounts for 10% of the effective volume of the upflow anaerobic sludge blanket reactor.

[0020] Optionally, the upflow anaerobic sludge blanket reactor is provided with an external water circulation insulation layer, and the temperature of the upflow anaerobic sludge blanket reactor is controlled to be (35±1)°C.

[0021] Optionally, the ozone is produced by an air source ozone generator.

[0022] Optionally, the pH of the wastewater is adjusted to 6.8-7.2 by adding sodium bicarbonate.

[0023] The wastewater treatment method provided in the embodiments of this application pre-treats the wastewater with ozone oxidation and adjusts the pH to 6.8-7.2. The wastewater is then inoculated with sludge in an upflow anaerobic sludge blanket reactor and treated with specially prepared iron oxide nano-modified honeycomb stone. This application establishes a synergistically enhanced UASB process using ozone and iron oxide nano-modified honeycomb stone. The process shortens startup time by 18 days compared to conventional UASB reactors, allows for a maximum organic load that is 2-4 times that of conventional UASB reactors, and increases average daily methane production by 10-30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic diagram of an experimental device provided in an embodiment of the present application;

[0025] FIG2 is an SEM image of the honeycomb stone before and after modification provided in an embodiment of the present application;

[0026] FIG3 is a COD removal efficiency effect diagram provided in an embodiment of the present application;

[0027] FIG4 is a schematic diagram of the influent organic load and methane production provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0029] In order to enhance the anaerobic efficiency and load shock resistance of the UASB reactor, the present embodiment proposes a method for optimizing the UASB anaerobic process by using ozone and iron oxide nano-modified honeycomb stone. First, ozone oxidation improves the biodegradability of the waste incineration leachate, reduces the biotoxicity of the leachate, and enhances the microbial activity within the UASB reactor. Second, the addition of iron oxide nano-modified honeycomb stone to the UASB reactor facilitates the biofilm formation and growth of microorganisms, reduces sludge loss caused by the impact of rising flow rate and gas production on anaerobic sludge, and maintains a high biomass and a suitable environment for microbial growth.

[0030] Specifically, ozone oxidation can reduce the biological toxicity of wastewater and improve its biodegradability. During the ozonation process, ozone molecules and hydroxyl radicals produced by ozone can react directly or indirectly with pollutants in the wastewater. In direct reactions, due to the strong oxidizing properties of ozone, ozone molecules or single oxygen atoms directly undergo redox reactions with most organic matter in the wastewater, and organic matter containing unsaturated bonds is removed. In indirect reactions, highly active hydroxyl radicals are produced during the oxidation process. Hydroxyl radicals have high redox potentials and interact with organic pollutants in the leachate to achieve chain scission and ring opening of chain or ring molecules in toxic and difficult-to-degrade organic matter. The ozone oxidation process is a feasible pre-biological treatment method.

[0031] Honeycomb stone has the characteristics of low density, large specific surface area, internal porosity, and high chemical stability. It is a good support and adsorption material, and the raw materials of honeycomb stone are easily available and low in cost. After being subjected to iron oxide nano-modification, the specific surface area and adsorption performance of the modified material are further increased. Adding it to the reactor is conducive to the contact and biofilm formation of microorganisms, providing a good growth environment for microbial growth. In addition, ozone has good effects in disinfection, sterilization, deodorization, decolorization, and improving the biodegradability of wastewater without secondary pollution. This application uses ozone as a pretreatment method for the UASB anaerobic reactor to reduce the toxicity of landfill leachate, improve its biodegradability, and further improve the anaerobic digestion efficiency of the UASB reactor.

[0032] The present invention provides a method for treating wastewater, comprising the following steps:

[0033] The honeycomb stone is heated in the presence of ferric sulfate, urea and deionized water, and then annealed to obtain iron oxide nano-modified honeycomb stone.

[0034] After pre-treatment of wastewater with ozone oxidation, the pH value was adjusted to 6.8-7.2;

[0035] The wastewater is treated by inoculating sludge in an upflow anaerobic sludge blanket reactor and adding the iron oxide nano-modified honeycomb stone.

[0036] Among them, the nano-iron oxide modified honeycomb stone process is an improvement on the traditional process technology. The nano-iron oxide modified honeycomb stone is a porous material with a large specific surface area, which can provide attachment sites for the growth and reproduction of microorganisms. The microorganisms form a biofilm on the surface of the material. The material is a conductive material and can enhance the anaerobic digestion methanogenesis by stimulating direct interspecies electron transfer (DIET), thereby shortening the reactor startup time and improving the UASB's ability to withstand shock loads; ozone synergistically with nano-iron oxide modified honeycomb stone not only improves the UASB reactor's ability to degrade organic matter, but also increases the relative abundance of microorganisms with the ability to promote electron transfer, thereby enhancing the biological methanogenesis performance.

[0037] The iron oxide nano-modified honeycomb stone can be prepared by the following method: wash the honeycomb stone with deionized water to remove soluble impurities on the surface, then dry it in an electric constant-temperature forced-air drying oven at 100°C for 12 hours. Weigh 10g of the honeycomb stone into a conical flask. Add 20.0g of ferric sulfate, 12.0g of urea, and 50mL of deionized water to a beaker and stir on a magnetic stirrer for 10 minutes to dissolve. The solution is transferred to the conical flask, sealed, and placed in an oven at 100°C for 12 hours, then cooled naturally to room temperature. The precipitate is collected and washed with deionized water. Finally, the precursor is annealed at 600°C for 4 hours.

[0038] Among them, the leachate from the waste incineration plant is treated, the UASB reactor is inoculated with sludge and iron oxide nano-modified honeycomb stone is added. The incineration leachate is treated as the object, and the incineration leachate is first pre-treated with ozone.

[0039] The pH of the influent incineration leachate is adjusted to 6.8-7.2 by adding sodium bicarbonate.

[0040] The startup phase is divided into three operating conditions, each lasting 20 days. Operating condition 1: hydraulic retention time is 22 hours; operating condition 2 (21-40 days): hydraulic retention time is 20.5 hours; operating condition 3 (41-60 days): hydraulic retention time is 19 hours. By the end of the startup phase, the influent organic load is increased to 10kgCOD / (m 3 d) or above.

[0041] The load impact stage is divided into three working conditions. Working condition 4 (61-90 days), hydraulic retention time is 18h, OLR is increased to 25kgCOD / (m 3 d); Operating condition 5 (91-130 days), hydraulic retention time is 16h, OLR is increased to 37kgCOD / (m 3 ·d) and then dropped to 15kgCOD / (m 3 d); Operating condition 6 (131-165 days), hydraulic retention time is 14.5h, OLR is increased to 70kgCOD / (m 3 ·d).

[0042] Among them, the leachate from waste incineration power generation is treated with ozone oxidation, and the ozone is produced by an air source ozone generator.

[0043] Among them, nano-modified honeycomb stone carriers with different particle sizes of iron oxide are added to the UASB reactor. Particles of different sizes will lead to different degrees of pressure gradients and liquid flows. Anaerobic digestion is a complex biological reaction process, which may produce different reaction conditions in different areas. Uneven synthetic materials can provide more diverse biological attachment environments, resulting in richer microbial communities, which help to improve treatment efficiency and stability. Such non-uniformity can make the reactor more flexible and can better cope with load fluctuations or changes in wastewater characteristics. The modified honeycomb stone added in this application has a particle size between 1 and 3 mm, and the addition amount accounts for 10% (250 mL) of the total volume of the reactor. Because honeycomb stone is a natural material, it is impossible to guarantee the uniformity of all particle sizes. If the particle size is too large, it will cause pipe blockage and deposit at the bottom of the reactor. If it is too small, it will flow out of the reactor with the effluent, resulting in a reduction in the amount of carrier added. Therefore, honeycomb stone with a particle size of 1 to 3 mm is selected as the reactor carrier material.

[0044] The UASB reactor is provided with an external water circulation insulation layer, and the temperature of the UASB reactor is controlled to be (35±1)°C.

[0045] The pH of the UASB influent was adjusted to between 6.8 and 7.2.

[0046] Among them, the organic load of the UASB reactor is steadily increased. The specific operation is shown in Table 1:

[0047] Table 1 Reactor operating conditions

[0048] The following will be combined with the wastewater treatment method of this application to clearly and completely describe the technical solutions in the examples of this application. Obviously, the described examples are only part of the examples of this application, not all of them. Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial sources.

[0049] In addition, it should be noted that the numerical values ​​given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0050] In this embodiment, the wastewater treatment method includes the following steps:

[0051] Step 1: Wash the honeycomb stone with deionized water to remove soluble impurities on the surface. Dry the stone in an electric constant-temperature forced-air drying oven at 100°C for 12 hours. Weigh 10g of the honeycomb stone into an Erlenmeyer flask. Add 20.0g of ferric sulfate, 12.0g of urea, and 50mL of deionized water to a beaker and stir on a magnetic stirrer for 10 minutes to dissolve. Transfer the solution to the aforementioned Erlenmeyer flask, seal it, and place it in an oven at 100°C for 12 hours, then cool it naturally to room temperature. Collect the precipitate and wash it with deionized water. Finally, anneal the precursor at 600°C for 4 hours. This yields iron oxide nano-modified honeycomb stone.

[0052] Step 2: The fresh landfill leachate from the regulating tank of a waste incineration power plant in Hefei was used as the treatment object. The incineration leachate was first pretreated with ozone, and then the UASB reactor was inoculated with sludge and iron oxide nano-modified honeycomb stone was added.

[0053] Step 3: Adjust the pH of the influent incineration leachate to 6.8-7.2 by adding sodium bicarbonate.

[0054] Step 4: The startup phase is divided into three operating conditions, each lasting 20 days. Operating condition 1: hydraulic retention time is 22 hours; operating condition 2 (21-40 days): hydraulic retention time is 20.5 hours; operating condition 3 (41-60 days): hydraulic retention time is 19.2 hours. By the end of the startup phase, COD concentration increased from 500mg / L to 9500mg / L and influent organic load increased to 10kgCOD / (m 3 d) or above.

[0055] Step 6: The load shock stage is divided into three working conditions. Working condition 4 (61-90 days), hydraulic retention time is 18.1h, COD concentration is 10000~15000mg / L, OLR is increased to 24kgCOD / (m 3 d); Operating condition 5 (91-130 days), COD concentration is 16400~20800mg / L, hydraulic retention time is 16.2h, OLR is increased to 37kgCOD / (m 3 ·d) and then dropped to 15kgCOD / (m 3 d); Operating condition six (131-165 days), the hydraulic retention time is 14.6h, wherein, as shown in the schematic diagram of the experimental apparatus in FIG1 , the control group is the R1 reactor (traditional UASB reactor), and the R2 reactor is the ozone and iron oxide nano-modified honeycomb stone optimized UASB reactor corresponding to the embodiment of the present application. The COD concentration of the R1 reactor is 5000-9000 mg / L, and the OLR is maintained at 8.5-13.88 kgCOD / (m 3 d), the COD concentration of R2 is 25000~45000mg / L, and OLR continues to increase to 70kgCOD / (m 3 ·d).

[0056] Scanning electron microscopy observations of the morphology of the honeycomb stone before and after modification in the above embodiment are shown in Figure 2. Figure 2a is a SEM image of the honeycomb stone before modification, showing that the surface of the honeycomb stone particles is honeycomb-shaped with a number of pores randomly distributed. Figure 2b is a SEM image of the honeycomb stone after iron oxide nano-modification, showing that the surface of the honeycomb stone is completely covered with spherical iron oxide.

[0057] FIG3 is a COD removal rate effect diagram provided in the embodiment of the present application. In the initial stage of the startup, COD Cr The removal rate gradually increased, and the COD Cr The removal rate reached 90% on the 30th day, and the UASB reactor was started up. The R1 reactor was not started up until the 48th day. From the 60th to the 130th day, the influent organic load of R1 and R2 was kept the same. On the 75th day, the influent organic load was 18.01 kgCOD / (m 3 d) COD of R1 Cr The removal rate dropped to 86.66%. On the 102nd day, the load continued to increase to 37.08 kgCOD / (m 3 d) COD of R1 Cr The removal rate dropped to 71.60%, while the R2 reactor always maintained more than 90% of COD CrAfter 130 days, the water was separated and R2 continued to increase the influent concentration to explore the maximum organic load it could withstand. On the 156th day, when the influent organic load of the R2 reactor was 57.32 kgCOD / (m 3 ·d), COD Cr The removal rate dropped to 88.74%.

[0058] Figure 4 is a schematic diagram of the influent organic load and methane production provided by the examples of this application. As the influent organic load increases, the daily methane production gradually increases. Under the same load in the first 130 days, the average daily methane production of R2 reactor is 20.11% higher than that of R1 reactor.

[0059] In summary, the combined process of ozone and nano-iron oxide-modified honeycomb stone-enhanced UASB reactor provided in the present embodiment shortens the startup time. The present invention can complete startup on the 30th day, while the control reactor (R1) takes 48 days.

[0060] On the other hand, the ozone-assisted UASB reactor process enhanced by nano-iron oxide-modified honeycomb stone provided in the present embodiment improves the load shock resistance. The maximum organic load that this application can withstand is 2 to 4 times that of the control group.

[0061] On the other hand, the combined ozone-assisted UASB reactor process enhanced by nano-iron oxide-modified honeycomb stone enhances anaerobic digestion efficiency. The average daily methane production in this application increased by 10% to 30% compared to the control group, and the organic matter removal rate increased by 5% to 20%.

[0062] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0063] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A wastewater treatment method, characterized in that, comprising: heating honeycomb stone under the action of ferric sulfate, urea and deionized water, and performing annealing treatment to obtain iron oxide nano-modified honeycomb stone; performing ozone oxidation pretreatment on the wastewater and adjusting the pH value to 6.8 - 7.2; inoculating sludge in an upflow anaerobic sludge bed reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater.

2. The wastewater treatment method according to claim 1, characterized in that, the step of heating honeycomb stone under the action of ferric sulfate, urea and deionized water and performing annealing treatment to obtain iron oxide nano-modified honeycomb stone includes: placing honeycomb stone in ferric sulfate, urea and deionized water, mixing evenly, then placing it at 100 °C for heating treatment for 12 h, after cooling and washing the precipitate, annealing the obtained precursor at 600 °C for 4 hours to obtain iron oxide nano-modified honeycomb stone.

3. The wastewater treatment method according to claim 1, characterized in that, the step of heating honeycomb stone under the action of ferric sulfate, urea and deionized water and performing annealing treatment to obtain iron oxide nano-modified honeycomb stone includes: weighing 10 g of honeycomb stone and putting it into a conical flask, adding 20.0 g of ferric sulfate, 12.0 g of urea and 50 mL of deionized water into a beaker, placing it on a magnetic stirrer and stirring for dissolution for 10 min; transferring the solution into the conical flask, sealing the conical flask and putting it into an oven for heating at 100 °C for 12 h, then naturally cooling to room temperature; collecting the precipitate and washing it with deionized water; finally, annealing the precursor at 600 °C for 4 hours to obtain iron oxide nano-modified honeycomb stone.

4. The wastewater treatment method according to claim 1, characterized in that, the process of inoculating sludge in an upflow anaerobic sludge bed reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater includes a startup stage and a load shock stage; Among them, the start-up stage includes operating condition 1, operating condition 2, and operating condition 3, each lasting for 20 days; operating condition 1 corresponds to days 1-20, with a hydraulic retention time of 22 ± 0.2 h; operating condition 2 corresponds to days 21-40, with a hydraulic retention time of 20.5 ± 0.2 h; operating condition 3 corresponds to days 41-60, with a hydraulic retention time of 19 ± 0.2 h. By the end of the start-up stage, the influent organic load is increased to more than 6-10 kg COD / (m 3 ·d). The load impact stage includes operating condition four, operating condition five, and operating condition six; operating condition four corresponds to days 61 - 90, with a hydraulic retention time of 18 ± 0.2 h and the influent organic load increased to 24 kg COD / (m 3 ·d); operating condition five corresponds to days 91 - 130, with a hydraulic retention time of 16 ± 0.2 h and the influent organic load increased to 37 kg COD / (m 3 ·d) and then decreased to 15 kg COD / (m 3 ·d); operating condition six corresponds to days 131 - 165, with a hydraulic retention time of 14.5 ± 0.2 h and the influent organic load increased to 70 kg COD / (m 3 ·d).

5. The wastewater treatment method according to claim 1, characterized in that, in the step of inoculating sludge in an upflow anaerobic sludge bed reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater, the particle size of the iron oxide nano-modified honeycomb stone is 1.00 mm - 3.00 mm.

6. The wastewater treatment method according to claim 1, characterized in that, in the step of inoculating sludge in an upflow anaerobic sludge bed reactor and adding the iron oxide nano-modified honeycomb stone to treat the wastewater, the addition amount of the iron oxide nano-modified honeycomb stone accounts for 10% of the effective volume of the upflow anaerobic sludge bed reactor.

7. The wastewater treatment method according to claim 1, characterized in that, the upflow anaerobic sludge bed reactor is provided with an external water circulation insulation layer, and the temperature of the upflow anaerobic sludge bed reactor is controlled at (35 ± 1) °C.

8. The wastewater treatment method according to claim 1, characterized in that, the ozone is prepared by an air source ozone generator.

9. The wastewater treatment method according to claim 1, characterized in that, Adjust the pH of the wastewater to 6.8 - 7.2 by adding sodium bicarbonate.

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