Wastewater treatment device and method combining ozone catalytic oxidation and biological activated carbon

Abstract

This disclosure relates to a wastewater treatment apparatus and method using ozone catalytic oxidation combined with biological activated carbon. The apparatus includes a catalytic oxidation reactor and a biological activated carbon reactor. The biological activated carbon reactor is coaxially embedded outside the catalytic oxidation reactor. The catalytic oxidation reactor includes a fluidization zone, a sedimentation zone, a solid-liquid separation zone, a first inlet, an ozone inlet, a biofilm-containing activated carbon inlet, a debiofilm-removed activated carbon outlet, a first gas outlet, and a first outlet. The biological activated carbon reactor has a second inlet, an oxygen-containing gas inlet, a debiofilm-removed activated carbon inlet, a biofilm-containing activated carbon outlet, a second gas outlet, and a second outlet. The second inlet is connected to the first outlet, the debiofilm-removed activated carbon inlet is connected to the debiofilm-removed activated carbon outlet, the biofilm-containing activated carbon outlet is connected to the biofilm-containing activated carbon inlet, and the oxygen-containing gas inlet is connected to the first outlet. This method improves wastewater treatment efficiency and reduces flushing energy consumption.

Description

Technical Field

[0001] This disclosure relates to the field of wastewater treatment, specifically to a wastewater treatment device and method that combines ozone catalytic oxidation with biological activated carbon. Background Technology

[0002] Industrial and domestic pollutants discharged into the environment pollute water bodies. Deteriorating water quality not only causes water shortages in many areas and increases the cost of water access for society as a whole, but also endangers human health. Therefore, it is necessary to treat wastewater containing pollutants to ensure it meets discharge standards. With the continuous development of water treatment technology, most wastewater can be treated. However, the treatment of recalcitrant organic wastewater has long been a challenge in water treatment technology and a significant problem troubling the environmental community worldwide.

[0003] This type of wastewater has poor biodegradability, making it difficult to treat directly using biological methods. Conventional methods such as filtration and flocculation are generally ineffective, while advanced treatment technologies such as activated carbon adsorption are too expensive. Membrane separation technology also faces certain difficulties in application due to high investment costs and membrane fouling issues.

[0004] In recent years, the use of ozone oxidation, a high-level oxidation technology, to degrade COD in recalcitrant wastewater has received widespread attention. In particular, ozone heterogeneous catalytic oxidation technology offers advantages such as high ozone utilization, strong oxidizing power, and low energy consumption and cost. It can effectively degrade recalcitrant pollutants in wastewater and improve its biodegradability. For example:

[0005] CN102070238A relates to a process for treating reverse osmosis concentrate from refining wastewater using ozone catalytic oxidation. The method includes: homogenizing the reverse osmosis concentrate in a regulating tank, then pumping it into a pre-aeration tank. In the tank, the water is fully mixed and reacted with ozone provided by an ozone generator. The effluent is then pumped into a catalytic oxidation reaction tower and flows into a clear water tank. The catalyst packed in the catalytic oxidation reaction tower utilizes modified γ-Al2O3 as a carrier for the wastewater treatment catalyst. This modified γ-Al2O3 possesses strong cracking and ring-opening functions and effectively utilizes the adjustable pore structure to create a multi-channel catalyst channel, increasing the contact area with the wastewater. This facilitates the accumulation of large organic molecules within the catalyst channels, accelerates the catalytic reaction rate, opens the ring chains of recalcitrant organic compounds, and further oxidizes and degrades them, thereby removing COD and petroleum pollutants.

[0006] CN104418423A provides a method for treating reverse osmosis concentrate by ozone catalytic oxidation. In this method, metal ions loaded with peanut shell activated carbon are added as a catalyst to the ozone oxidation wastewater treatment system for treating reverse osmosis concentrate, thereby promoting the degradation of organic pollutants in the concentrate.

[0007] While the ozone oxidation method described above can serve as an effective advanced treatment technology to further remove organic matter and meet increasingly stringent effluent discharge standards, it also faces challenges such as low O3 utilization efficiency and catalyst deactivation due to severe scaling on the catalyst surface. Furthermore, ozone catalytic oxidation processes are often combined with biochemical processes such as BAF (Biological Aeration Fluidization), and BAF processes also suffer from drawbacks such as easy packing material caking and high backwashing frequency. Summary of the Invention

[0008] The purpose of this disclosure is to provide a wastewater treatment device and method that combines ozone catalytic oxidation with biological activated carbon, which can couple the ozone catalytic oxidation process with the biochemical process, resulting in good wastewater treatment effect, avoiding catalyst caking, avoiding biochemical packing caking, and eliminating the need for backwashing of the biochemical unit.

[0009] To achieve the above objectives, the first aspect of this disclosure provides a wastewater treatment device combining ozone catalytic oxidation and biological activated carbon, comprising a catalytic oxidation reactor, a biological activated carbon reactor, and an ozone generator; wherein the biological activated carbon reactor is coaxially embedded outside the catalytic oxidation reactor; the catalytic oxidation reactor includes a fluidization zone, a sedimentation zone, a solid-liquid separation zone, a first inlet, an ozone inlet, a biofilm-containing activated carbon inlet, a debiofilm-free activated carbon outlet, a first gas outlet, and a first outlet; wherein the sedimentation zone is disposed above and communicates with the fluidization zone, the first inlet, the ozone inlet, and the biofilm-containing activated carbon inlet are disposed in the fluidization zone, and the debiofilm-free activated carbon outlet and the first gas outlet are disposed in the sedimentation zone; the solid-liquid separation zone includes a fluidization zone, a sedimentation zone, a solid-liquid separation zone, a solid-liquid separation zone, a first inlet, an ozone inlet, a biofilm-containing activated carbon inlet, a debiofilm-free activated carbon outlet, and a first gas outlet; the solid-liquid separation zone includes a fluidization zone, a sedimentation zone, a solid-liquid separation ... A liquid separation zone is fitted outside the settling zone. A three-phase separator is installed inside the settling zone, and the settling zone is connected to the solid-liquid separation zone via an overflow device located at its upper part. The first outlet is located in the solid-liquid separation zone. The biological activated carbon reactor has a second inlet, an oxygen-containing gas inlet, a biofilm-removing activated carbon inlet, a biofilm-containing activated carbon outlet, a second gas outlet, and a second outlet. The second inlet is connected to the first outlet of the solid-liquid separation zone. The biofilm-removing activated carbon inlet is connected to the biofilm-removing activated carbon outlet of the settling zone. The biofilm-containing activated carbon outlet is connected to the biofilm-containing activated carbon inlet of the fluidization zone. The oxygen-containing gas inlet is connected to the first gas outlet of the settling zone, and the ozone inlet is connected to an ozone source.

[0010] Optionally, the catalytic oxidation reactor further includes a transition zone, wherein the fluidization zone, transition zone, and settling zone are connected sequentially from bottom to top and coaxially arranged; the horizontal cross-sectional areas of the fluidization zone, transition zone, and settling zone increase sequentially; the first water inlet, ozone inlet, and biofilm-containing activated carbon inlet are located at the bottom of the fluidization zone; the first gas outlet is located at the top of the settling zone; and the biofilm-containing activated carbon inlet is located above the ozone inlet; the first water outlet is located at the upper part of the solid-liquid separation zone; and a slag discharge port is also provided at the bottom of the solid-liquid separation zone.

[0011] Optionally, in the biological activated carbon reactor, the debiofilm activated carbon inlet and the second outlet are respectively located at the upper part of the biological activated carbon reactor; the second gas outlet is located at the top of the biological activated carbon reactor; the second water inlet, the oxygen-containing gas inlet, and the biofilm-containing activated carbon outlet are respectively located at the lower part of the biological activated carbon reactor; the debiofilm activated carbon inlet of the biological activated carbon reactor and the debiofilm activated carbon outlet of the settling zone are connected through an upper packing pipe; the biofilm-containing activated carbon outlet of the biological activated carbon reactor and the biofilm-containing activated carbon inlet of the fluidization zone are connected through a lower packing pipe.

[0012] Optionally, the horizontal position of the debiofilm activated carbon outlet of the catalytic oxidation reactor is higher than the debiofilm activated carbon inlet of the biological activated carbon reactor, so that the upper packing tube slopes downward from the debiofilm activated carbon outlet to the debiofilm activated carbon inlet; the horizontal position of the biofilm-containing activated carbon outlet of the biological activated carbon reactor is higher than the biofilm-containing activated carbon inlet of the catalytic oxidation reactor, so that the lower packing tube slopes downward from the biofilm-containing activated carbon outlet to the biofilm-containing activated carbon inlet; Optionally, the bottom of the biological activated carbon reactor is located above the bottom of the fluidization zone of the catalytic oxidation reactor, and the top of the biological activated carbon reactor is located below the top of the settling zone of the catalytic oxidation reactor; Optionally, the device further includes an ozone generator, the ozone outlet of which is connected to the ozone inlet of the catalytic oxidation reactor.

[0013] Optionally, the catalytic oxidation reactor includes an inner shell and an outer shell arranged vertically. The inner shell includes a cylindrical fluidizing zone, a transition zone, and a cylindrical settling zone connected sequentially from bottom to top. The diameter of the settling zone is larger than the diameter of the fluidizing zone, and the transition zone is formed into an inverted frustum shape. The outer shell is fitted outside the inner shell of the settling zone and forms a cylindrical solid-liquid separation zone. Optionally, the bottom surface of the solid-liquid separation zone is flush with the bottom surface of the settling zone in the horizontal direction. The top edge of the solid-liquid separation zone is lower than the top edge of the settling zone. The bio-activated carbon reactor includes a cylindrical shell arranged vertically, and the diameter of the shell of the bio-activated carbon reactor is larger than the diameter of the fluidizing zone and the transition zone.

[0014] Optionally, the ratio of the top diameter of the transition zone to the diameter of the fluidization zone is 1.5 to 20:1, preferably 2 to 10:1; the ratio of the height to the diameter of the fluidization zone is 2 to 20:1, preferably 5 to 10:1; the ratio of the height of the transition zone to the height of the settling zone is 0.2 to 5:1, preferably 0.5 to 2:1; and the ratio of the diameter of the solid-liquid separation zone to the diameter of the settling zone is 1.2 to 5:1, preferably 1.5:3:1.

[0015] The second aspect of this disclosure provides a wastewater treatment method using ozone catalytic oxidation combined with biological activated carbon. This method employs the apparatus described in the first aspect of this disclosure and includes the following steps: S1, introducing wastewater containing organic matter, ozone, and activated carbon carrier into the fluidized zone of the catalytic oxidation reactor for fluidized catalytic oxidation reaction; the resulting reaction mixture enters the sedimentation zone and undergoes sedimentation separation in the three-phase separator to obtain debiofilm activated carbon, a first gas, and a solid-liquid mixture; the solid-liquid mixture then enters the solid-liquid separation zone for solid-liquid separation to obtain first treated water and residue; S2, the wastewater from the catalytic oxidation reactor... The first treated water, the debiofilm activated carbon, and the oxygen-containing gas from the oxidation reactor enter the biological activated carbon reactor, whereby the remaining organic matter in the first treated water undergoes an aerobic biochemical reaction with the wastewater treatment bacteria in the biological activated carbon reactor under aeration conditions, yielding purified water, biofilm-containing activated carbon, and a second gas; wherein the oxygen-containing gas includes the first gas from the catalytic oxidation reactor; S3, the biofilm-containing activated carbon from the biological activated carbon reactor is returned to the fluidization zone of the catalytic oxidation reactor to contact the wastewater to be treated and ozone, thereby washing and regenerating the biofilm-containing activated carbon.

[0016] Optionally, in step S1, based on the amount of wastewater introduced in 1L, the flow rate of ozone is 50-20000mL / min, preferably 200-5000mL / min; based on the amount of wastewater introduced in 1L, the amount of activated carbon carrier introduced is 50-5000g, preferably 100-2000g; the residence time of the wastewater in the fluidization zone is 0.05-5h, preferably 0.1-2h; the reaction temperature is 10-40℃, preferably 15-30℃; the COD of the wastewater is 60-150mg / L, and the BOD / COD ratio is less than 0.25.

[0017] Optionally, in step S2, based on the amount of wastewater introduced in 1L, the dissolved oxygen in the biological activated carbon reactor is 1-8 mg, preferably 2-4 mg; based on the amount of wastewater introduced in 1L, the amount of biofilm-degraded activated carbon introduced is 2-500 g, preferably 5-200 g; the residence time of the first treated wastewater in the biological activated carbon reactor is 0.2-12 h, preferably 1-6 h; and the reaction temperature is 10-40℃, preferably 20-35℃.

[0018] Optionally, the activated carbon support has an average particle size of 60–200 mesh, an average pore size of 0.01–10 nm, and a total pore volume of 0.001–0.5 cm³. 3 / g, BET specific surface area is 1~1000m² 2 / g.

[0019] Through the above technical solution, this disclosure provides a wastewater treatment device and method combining ozone catalytic oxidation with biological activated carbon. The coupling of ozone catalytic oxidation and biological activated carbon processes results in excellent wastewater treatment performance. By introducing the biofilm-containing activated carbon obtained from the biochemical reaction in biological activated carbon reactor II into catalytic oxidation reactor I, both the catalytic action of the activated carbon carrier for ozone catalytic oxidation and the scouring effect of water and air flow in fluidized zone 1, along with the oxidation effect of ozone, cause the aged biofilm in the activated carbon carrier to detach and the carrier to be renewed, eliminating the need for additional equipment to backwash the carrier after the reaction in biological activated carbon reactor II. The fluidized catalytic oxidation reaction also avoids catalyst caking in catalytic oxidation reactor I; the suspended biochemical reaction in biological activated carbon reactor II also avoids biochemical packing caking. This disclosure employs a unique reactor design that combines the advantages of fluidized beds and suspended beds, simplifying the internal structure and reducing the energy consumption required for separate backwashing of the catalyst to remove the biofilm.

[0020] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is an exemplary structural schematic diagram of a wastewater treatment device combining ozone catalytic oxidation and biological activated carbon, as provided in this disclosure.

[0023] Figure 2 This is an exemplary structural schematic diagram of a catalytic oxidation reactor provided in this disclosure.

[0024] Explanation of reference numerals in the attached figures

[0025] 1-Catalytic oxidation reactor, 1-Fluidized zone, 2-Transition zone, 3-Settling zone, 4-Solid-liquid separation zone, 5-Upper packing tube, 6-Lower packing tube, 7-First water inlet, 8-Ozone inlet, 9-Three-phase separator, 10-First gas outlet, 11-Overflow device, 12-First water outlet, 13-Slag discharge port

[0026] II - Biological activated carbon reactor, 14 - Oxygen-containing gas inlet, 15 - Second water inlet, 16 - Second gas outlet, 17 - Second water outlet Detailed Implementation

[0027] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0028] In this disclosure, unless otherwise stated, the terms "first," "second," and "third" are used only to distinguish different components and do not imply any actual connection order. In this disclosure, directional terms such as "upper" and "lower" refer to the upper and lower positions of the device in its normal operating state, while "inner" and "outer" refer to the outline of the device.

[0029] like Figure 1 and Figure 2As shown, the first aspect of this disclosure provides a wastewater treatment device combining ozone catalytic oxidation and biological activated carbon, including a catalytic oxidation reactor I and a biological activated carbon reactor II; wherein, the biological activated carbon reactor II is coaxially embedded outside the catalytic oxidation reactor I; the catalytic oxidation reactor I includes a fluidization zone 1, a settling zone 3, a solid-liquid separation zone 4, a first inlet 7, an ozone inlet 8, a biofilm-containing activated carbon inlet, a debiofilm-free activated carbon outlet, a first air outlet 10, and a first outlet 12; wherein the settling zone 3 is located above and connected to the fluidization zone 1, the first inlet 7, the ozone inlet 8, and the biofilm-containing activated carbon inlet are located in the fluidization zone 1, and the debiofilm-free activated carbon outlet and the first air outlet 10 are located in the settling zone 3; the solid-liquid separation zone 4 is sleeved outside the settling zone 3, a three-phase separator 9 is provided inside the settling zone 3, and the settling zone 3 is connected to the solid-liquid separation zone 4 through an overflow device 11 located above it, and the first outlet 12 is located in the solid-liquid separation zone 4;

[0030] The biological activated carbon reactor II is equipped with a second inlet 15, an oxygen-containing gas inlet 14, a biofilm-removing activated carbon inlet, a biofilm-containing activated carbon outlet, a second gas outlet 16, and a second outlet 17. The second inlet 15 is connected to the first outlet 12 of the solid-liquid separation zone 4, the biofilm-removing activated carbon inlet is connected to the biofilm-removing activated carbon outlet of the settling zone 3, the biofilm-containing activated carbon outlet is connected to the biofilm-containing activated carbon inlet of the fluidization zone 1, the oxygen-containing gas inlet 14 is connected to the first gas outlet 10 of the settling zone 3, and the ozone inlet 8 is connected to the ozone source.

[0031] The wastewater treatment device provided in this disclosure couples ozone catalytic oxidation with biological activated carbon technology, resulting in excellent wastewater treatment performance. By introducing the biofilm-containing activated carbon obtained from the biochemical reaction in biological activated carbon reactor II into catalytic oxidation reactor I, ozone catalytic oxidation can be carried out using the catalysis of the activated carbon carrier. Furthermore, the scouring effect of water and air flow in fluidized zone 1, along with the oxidation effect of ozone, causes the aged biofilm in the activated carbon carrier to detach, thus renewing the carrier. No additional backwashing device is needed for the carrier after the reaction in biological activated carbon reactor II. The fluidized catalytic oxidation reaction also avoids catalyst caking in catalytic oxidation reactor I. The suspended biochemical reaction in biological activated carbon reactor II also avoids caking of the biochemical packing. This disclosure employs a unique reactor design that combines the advantages of fluidized beds and suspended beds, simplifying the internal structure and reducing the energy consumption required for additional backwashing.

[0032] In one specific implementation, such as Figure 1 As shown, the device also includes an ozone generator III, the ozone outlet of which is connected to the ozone inlet 8 of the catalytic oxidation reactor I.

[0033] In a preferred embodiment, such as Figure 2 As shown, the catalytic oxidation reactor I also includes a transition zone 2. The fluidization zone 1, transition zone 2 and settling zone 3 are connected sequentially from bottom to top and are arranged coaxially. The horizontal cross-sectional areas of the fluidization zone 1, transition zone 2 and settling zone 3 increase sequentially.

[0034] The first water inlet 7, ozone inlet 8, and biofilm-containing activated carbon inlet are located at the bottom of fluidization zone 1; the first air outlet 10 is located at the top of settling zone 3; and the biofilm-containing activated carbon inlet is located above ozone inlet 8.

[0035] The first outlet 12 is located at the upper part of the solid-liquid separation zone 4;

[0036] The bottom of the solid-liquid separation zone 4 is also equipped with a slag discharge port 13.

[0037] In this disclosure, the horizontal cross-sectional areas and diameters of the fluidization zone 1, transition zone 2, and settling zone 3 increase sequentially, which reduces the flow velocity of the mixture from the fluidization zone 1 after entering the transition zone and settling zone, thus facilitating the settling of the activated carbon carrier after biofilm removal at the bottom of the settling zone 3.

[0038] In one implementation, such as Figure 1 As shown, in the biological activated carbon reactor II, the biofilm-removing activated carbon inlet and the second water outlet 17 are located at the upper part of the biological activated carbon reactor II; the second air outlet 16 is located at the top of the biological activated carbon reactor II; the second water inlet 15, the oxygen-containing gas inlet 14 and the biofilm-containing activated carbon outlet are located at the lower part of the biological activated carbon reactor II.

[0039] The biofilm-free activated carbon inlet of biological activated carbon reactor II is connected to the biofilm-free activated carbon outlet of sedimentation zone 3 through upper packing pipe 5; the biofilm-containing activated carbon outlet of biological activated carbon reactor II is connected to the biofilm-containing activated carbon inlet of fluidization zone 1 through lower packing pipe 6.

[0040] In one implementation, such as Figure 1 and Figure 2 As shown, the catalytic oxidation reactor I includes an inner shell and an outer shell arranged in a vertical direction. The inner shell includes a cylindrical fluidization zone 1, a transition zone 2 and a cylindrical settling zone 3 connected sequentially from bottom to top. The diameter of the settling zone 3 is larger than the diameter of the fluidization zone 1. The transition zone 2 is formed into an inverted frustum shape. The outer shell is fitted outside the inner shell of the settling zone 3 and forms a cylindrical solid-liquid separation zone 4.

[0041] Optionally, the bottom surface of the solid-liquid separation zone 4 is flush with the bottom surface of the settling zone 3 in the horizontal direction; the top edge of the solid-liquid separation zone 4 is lower than the top edge of the settling zone 3.

[0042] The biological activated carbon reactor II includes a cylindrical shell arranged in a vertical direction, and the diameter of the shell of the biological activated carbon reactor II is larger than the diameter of the fluidization zone 1 and the transition zone 2.

[0043] like Figure 1 and Figure 2 As shown, the specific process principle of the wastewater treatment device provided according to the foregoing embodiments includes:

[0044] The wastewater to be treated enters the fluidized zone 1 of the ozone catalytic oxidation reactor I through the first inlet 7. Simultaneously, ozone enters the fluidized zone 1 through the ozone inlet 8 from the ozone generator III. Biofilm-containing activated carbon from the biological activated carbon reactor II enters the fluidized zone 1 through the lower packing pipe 6 and the biofilm-containing activated carbon inlet. In the fluidized zone 1, the ozone catalytic oxidation reaction takes place under the catalysis of the activated carbon carrier. The fluidized zone 1 has a small diameter and high water and air flow velocities, and the carrier is in a fluidized state within it. Furthermore, through the scouring effect of the water and air flow in the fluidized zone 1, as well as the oxidation effect of ozone, the aged biofilm in the carrier detaches, and the carrier is renewed.

[0045] The reactants continue to move upwards, entering the bottom of the transition zone 2 from the top of the fluidization zone 1. The transition zone 2 is an inverted frustum-shaped cylinder with a larger diameter than the fluidization zone 1. Within the transition zone 2, the water and air flow velocities decrease as the diameter increases. Then, the reactants enter the bottom of the settling zone 3 from the top of the transition zone 2. A three-phase separator 9 is installed in the settling zone 3, where gas, liquid, and solid phases are separated. Waste gas is discharged from the first outlet 10 at the top of the settling zone 3 and introduced as oxygen-containing gas into the biological activated carbon reactor II via the oxygen-containing gas inlet 14 for deoxidation. The biofilm activated carbon settles to the bottom of the settling zone 3 and flows back to the upper part of the biological activated carbon reactor II through the upper packing pipe 5; water and biofilm detached from the biofilm activated carbon overflow from the overflow device 11 (e.g., overflow weir) at the top of the settling zone 3 into the solid-liquid separation zone 4 for solid-liquid separation, resulting in sludge and first treated water. The sludge is discharged through the sludge discharge port 13 at the bottom of the solid-liquid separation zone 4; the first treated water is led out through the first outlet 12 at the top of the solid-liquid separation zone 4 and then enters the biological activated carbon reactor II through the second inlet 15 at the bottom of the biological activated carbon reactor II.

[0046] In the biological activated carbon reactor II, aeration is carried out through the lower oxygen-containing gas inlet 14 (ozone tail gas from the first outlet also enters the biological activated carbon reactor II; oxygen-containing gas can also be added externally if oxygen-containing gas is insufficient), and a suspended aerobic biochemical reaction is performed. The waste gas (second gas) is discharged through the second outlet 16 set at the top, and the treated wastewater is discharged through the second outlet 17. The biofilm-loaded activated carbon obtained from the biochemical reaction is returned to the fluidization zone 1 in the ozone catalytic oxidation reactor I through the lower packing pipe 6 for recycling.

[0047] In one implementation, such as Figure 1 As shown, the horizontal position of the activated carbon outlet of the catalytic oxidation reactor I is higher than that of the activated carbon inlet of the biofilm-de-film reactor II, so that the upper packing tube 5 is inclined downward from the activated carbon outlet of the biofilm-de-film reactor II to the activated carbon inlet of the biofilm-de-film reactor II.

[0048] The biofilm-containing activated carbon outlet of the biological activated carbon reactor II is positioned higher than the biofilm-containing activated carbon inlet of the catalytic oxidation reactor I, so that the lower packing tube 6 slopes downwards from the biofilm-containing activated carbon outlet to the biofilm-containing activated carbon inlet. Optionally, the bottom of the biological activated carbon reactor II is located above the bottom of the fluidization zone 1 of the catalytic oxidation reactor I, and the top of the biological activated carbon reactor II is located below the top of the settling zone 3 of the catalytic oxidation reactor I. In this embodiment, the biological activated carbon reactor II is coaxially sleeved outside the catalytic oxidation reactor I, and the axial length of the biological activated carbon reactor II is less than the sum of the total axial lengths of the fluidization zone 1 and the transition zone 2 in the catalytic oxidation reactor I.

[0049] This disclosure utilizes inclined upper packing pipes 5 and lower packing pipes 6 to facilitate the recycling of activated carbon between catalytic oxidation reactor I and biological activated carbon reactor II. More specifically, multiple upper packing pipes 5 and lower packing pipes 6 can be installed according to actual needs, and these multiple upper packing pipes 5 and multiple lower packing pipes 6 can be symmetrically arranged around the activated carbon in catalytic oxidation reactor I and biological activated carbon reactor II, forming a central axis.

[0050] In one specific implementation, such as Figure 1 As shown, the activated carbon outlet for debiofilm removal in catalytic oxidation reactor I is located directly above the activated carbon inlet for debiofilm removal in biological activated carbon reactor II, and the upper packing tube 5 is set vertically.

[0051] In one specific embodiment, the ratio of the top surface diameter of the transition zone 2 to the diameter of the fluidization zone 1 is 1.5 to 20:1, preferably 2 to 10:1;

[0052] The height to diameter ratio of fluidization zone 1 is 2 to 20:1, preferably 5 to 10:1;

[0053] The height ratio of transition zone 2 to settlement zone 3 is 0.2 to 5:1, preferably 0.5 to 2:1;

[0054] The diameter ratio of the solid-liquid separation zone 4 to the sedimentation zone 3 is 1.2 to 5:1, preferably 1.5 to 3:1;

[0055] The biological activated carbon reactor II includes a cylindrical shell arranged in a vertical direction, and the diameter of the shell of the biological activated carbon reactor II is larger than the diameter of the fluidization zone 1 and the transition zone 2.

[0056] The second aspect of this disclosure provides a wastewater treatment method using ozone catalytic oxidation combined with biological activated carbon, the method employing the apparatus described in the first aspect of this disclosure, and comprising the following steps:

[0057] S1. The wastewater containing organic matter, ozone, and activated carbon carrier are introduced into the fluidized zone 1 of the catalytic oxidation reactor I for fluidized catalytic oxidation reaction. The resulting reaction mixture enters the sedimentation zone 3 and is separated by the three-phase separator 9 to obtain debiofilm activated carbon, a first gas, and a solid-liquid mixture. The solid-liquid mixture is then introduced into the solid-liquid separation zone 4 for solid-liquid separation to obtain the first treated water and residue.

[0058] S2. The first treated water, the debiofilm activated carbon, and the oxygen-containing gas from the catalytic oxidation reactor I are introduced into the biological activated carbon reactor II, so that the remaining organic matter in the first treated water and the wastewater treatment bacteria in the biological activated carbon reactor II undergo an aerobic biochemical reaction under aeration conditions to obtain purified water, biofilm activated carbon, and a second gas; wherein the oxygen-containing gas includes the first gas from the catalytic oxidation reactor I.

[0059] S3. The biofilm-containing activated carbon from the biological activated carbon reactor II is returned to the fluidization zone 1 of the catalytic oxidation reactor I to contact the wastewater to be treated and ozone, and the biofilm-containing activated carbon is washed and regenerated.

[0060] In one embodiment, in step S1, based on the amount of wastewater introduced in 1L, the flow rate of ozone is 50-20000mL / min, preferably 200-5000mL / min; based on the amount of wastewater introduced in 1L, the amount of activated carbon carrier introduced is 50-5000g, preferably 100-2000g; the residence time of the wastewater in the fluidization zone 1 is 0.05-5h, preferably 0.1-2h, and the reaction temperature is 10-40℃, preferably 15-30℃.

[0061] In one embodiment, the COD of the wastewater to be treated is 60-150 mg / L, and the BOD / COD ratio is less than 0.25.

[0062] In one embodiment, in step S2, based on the 1L of wastewater to be treated introduced, the dissolved oxygen in the biological activated carbon reactor II is 1-8mg, preferably 2-4mg.

[0063] Based on the amount of wastewater introduced into 1L of the wastewater to be treated, the amount of activated carbon introduced for biofilm removal is 2 to 500g, preferably 5 to 200g;

[0064] The first wastewater is retained in the biological activated carbon reactor II for 0.2 to 12 hours, preferably 1 to 6 hours; the reaction temperature is 10 to 40°C, preferably 20 to 35°C.

[0065] In one embodiment, additional air may be introduced into the biological activated carbon reactor II to control the dissolved oxygen level in the biological activated carbon reactor II to be 1-8 mg (calculated based on the amount of wastewater introduced per 1 L of the wastewater to be treated).

[0066] In one embodiment, the biofilm-containing activated carbon includes an activated carbon carrier and a biofilm attached to the surface of the activated carbon carrier;

[0067] The activated carbon carrier has an average particle size of 60–200 mesh, an average pore size of 0.01–10 nm, and a total pore volume of 0.001–0.5 cm³. 3 / g, BET specific surface area is 1~1000m² 2 / g.

[0068] In this disclosure, the wastewater treatment strains used in the biological activated carbon reactor II are selected from species conventionally chosen in the art and are obtained through acclimatization and cultivation in the reactor using conventional methods in the art. The acclimatization and cultivation of the strains can be adjusted in practical applications.

[0069] The present disclosure will be further illustrated below with reference to embodiments.

[0070] The activated carbon carrier (purchased from Tianjin Dexin) has an average particle size of 60–200 mesh, an average pore size of 0.01–10 nm, and a total pore volume of 0.001–0.5 cm³. 3 / g, BET specific surface area is 1~1000m² 2 / g.

[0071] COD and BOD in wastewater were detected using the dichromate method (HJ 828-2017) and the dilution and inoculation method (HJ 505-2009), respectively.

[0072] Example 1

[0073] use Figure 1 and Figure 2 The apparatus shown is used to treat reverse osmosis concentrate from a coal chemical plant. The wastewater has a COD of 120 mg / L and a BOD of 15 mg / L (BOD / COD ratio of 0.125). The process includes the following steps:

[0074] S1. The wastewater containing organic matter, ozone, and activated carbon carrier are introduced into the fluidized zone 1 of the catalytic oxidation reactor I for fluidized catalytic oxidation reaction. The resulting reaction mixture enters the sedimentation zone 3 and is separated by the three-phase separator 9 to obtain debiofilm activated carbon, a first gas, and a solid-liquid mixture. The solid-liquid mixture is then introduced into the solid-liquid separation zone 4 for solid-liquid separation to obtain the first treated water and residue.

[0075] In catalytic oxidation reactor I, based on the amount of wastewater introduced in 1L, the ozone dosage is 50mg, the ozone flow rate is 2000mL / min, the amount of activated carbon carrier introduced is 500g, the wastewater residence time in fluidized zone 1 is 0.5h, the temperature of fluidized zone 1 is 25℃, and the residence time in solid-liquid separation zone 4 is 1.5h.

[0076] S2. The first treated water from the catalytic oxidation reactor I, the debiofilm activated carbon, and the oxygen-containing gas (i.e., the first gas from the catalytic oxidation reactor I) are introduced into the biological activated carbon reactor II. The remaining organic matter in the first treated water undergoes an aerobic biochemical reaction with the wastewater treatment bacteria in the biological activated carbon reactor II under aeration conditions, yielding purified water, biofilm-containing activated carbon, and a second gas; wherein...

[0077] In biological activated carbon reactor II, based on the amount of wastewater introduced in 1L, the dissolved oxygen is controlled at 2-4mg (which can vary within this range depending on the actual situation), the amount of activated carbon introduced for biofilm removal is 25g, the hydraulic retention time is 3h, and the temperature is 25℃.

[0078] In this embodiment, the ratio of the top diameter of the transition zone 2 to the diameter of the fluidization zone 1 is 2.5:1; the ratio of the height of the fluidization zone 1 to its diameter is 5:1; and the ratio of the height of the transition zone 2 to the height of the settling zone 3 is 1.5:1.

[0079] The treated wastewater (secondary purified water) has a COD of 45 mg / L and a BOD of 5 mg / L.

[0080] Example 2

[0081] Using the same treatment apparatus and method as in Example 1, the secondary biochemical effluent (sewage to be treated) of a coal chemical enterprise was treated. The wastewater had a COD of 95 mg / L and a BOD of 13 mg / L (BOD / COD = 0.137).

[0082] In catalytic oxidation reactor I, based on the amount of wastewater introduced in 1L, the ozone dosage is 40mg, the ozone flow rate is 1600mL / min, the amount of activated carbon carrier introduced is 800g, the residence time of wastewater in the fluidized zone is 0.5h, the temperature of fluidized zone I is 30℃, and the residence time in the solid-liquid separation zone is 1.5h.

[0083] In biological activated carbon reactor II, based on the amount of wastewater introduced per 1L, the dissolved oxygen is controlled at 2-4mg, the amount of activated carbon introduced for biofilm removal is 80g, the hydraulic retention time is 3h, and the temperature is 30℃.

[0084] The treated wastewater (secondary purified water) has a COD of 28 mg / L and a BOD of 3 mg / L.

[0085] Example 3

[0086] The same wastewater, treatment apparatus, and treatment method as in Example 1 were used. The difference from Example 1 is that:

[0087] In catalytic oxidation reactor I, based on the amount of wastewater introduced in 1L, the ozone dosage is 20mg, the ozone flow rate is 100mL / min, the amount of activated carbon carrier introduced is 70g, the residence time of wastewater in fluidized zone 1 is 3h, the temperature of fluidized zone 1 is 24℃, and the residence time in solid-liquid separation zone 4 is 1.5h.

[0088] In biological activated carbon reactor II, based on the amount of wastewater introduced in 1L, the dissolved oxygen is controlled at 1-1.5mg, the amount of activated carbon introduced for biofilm removal is 300g, the hydraulic retention time is 0.5h, and the reaction temperature is 15℃.

[0089] The treated wastewater (secondary purified water) has a COD of 68 mg / L and a BOD of 7 mg / L.

[0090] Example 4

[0091] The same wastewater, treatment apparatus, and treatment method as in Example 1 were used. The difference from Example 1 is that:

[0092] The ratio of the top diameter of the transition zone 2 to the diameter of the fluidization zone 1 is 1.5:1; the ratio of the height to the diameter of the fluidization zone 1 is 3:1; the ratio of the height of the transition zone 2 to the height of the settling zone 3 is 1.5:1; and the ratio of the diameter of the solid-liquid separation zone 4 to the diameter of the settling zone 3 is 4:1.

[0093] Using the same process parameters as in Example 1, the final treated wastewater (second purified water) had a COD of 76 mg / L and a BOD of 8 mg / L.

[0094] As can be seen from the above embodiments, the ozone catalytic oxidation process coupled with the biological activated carbon process using the treatment device and method provided in this disclosure can effectively treat wastewater; and it reduces the energy consumption required for backwashing the catalyst to remove the biofilm separately.

[0095] Furthermore, comparing Example 1 with Example 3, it can be seen that the process parameters in the preferred embodiment were used in Example 1 in the catalytic oxidation reactor I and the biological activated carbon reactor II. The COD and BOD contents of the purified water obtained in Example 1 are lower, and the treatment effect is better.

[0096] Furthermore, comparing Example 1 with Example 4, it can be seen that the structural configuration of the catalytic oxidation reactor I in Example 1 meets the proportions of the preferred embodiment, and the COD and BOD content in the purified water obtained in Example 1 is lower, resulting in better treatment effect.

[0097] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0098] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0099] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A wastewater treatment device combining ozone catalytic oxidation and biological activated carbon, characterized in that, The reactor includes a catalytic oxidation reactor (I) and a biological activated carbon reactor (II); wherein the biological activated carbon reactor (II) is coaxially embedded outside the catalytic oxidation reactor (I); the catalytic oxidation reactor (I) includes a fluidization zone (1), a settling zone (3), a solid-liquid separation zone (4), a first inlet (7), an ozone inlet (8), a biofilm-containing activated carbon inlet, a debiofilm-free activated carbon outlet, a first gas outlet (10), and a first outlet (12); wherein the settling zone (3) is located above the fluidization zone (1) and adjacent to the biological activated carbon inlet (II). The fluidization zone (1) is connected, and the first inlet (7), ozone inlet (8) and biofilm-containing activated carbon inlet are located in the fluidization zone (1). The biofilm-removing activated carbon outlet and the first air outlet (10) are located in the settling zone (3). The solid-liquid separation zone (4) is sleeved outside the settling zone (3). A three-phase separator (9) is provided in the settling zone (3). The settling zone (3) is connected to the solid-liquid separation zone (4) through an overflow device (11) located above it. The first outlet (12) is located in the solid-liquid separation zone (4). The biological activated carbon reactor (II) is provided with a second inlet (15), an oxygen-containing gas inlet (14), a biofilm-removing activated carbon inlet, a biofilm-containing activated carbon outlet, a second gas outlet (16), and a second outlet (17); the second inlet (15) is connected to the first outlet (12) of the solid-liquid separation zone (4), the biofilm-removing activated carbon inlet is connected to the biofilm-removing activated carbon outlet of the settling zone (3), the biofilm-containing activated carbon outlet is connected to the biofilm-containing activated carbon inlet of the fluidization zone (1), the oxygen-containing gas inlet (14) is connected to the first gas outlet (10) of the settling zone (3), and the ozone inlet (8) is connected to an ozone source.

2. The apparatus according to claim 1, characterized in that, The catalytic oxidation reactor (I) further includes a transition zone (2), wherein the fluidization zone (1), the transition zone (2) and the settling zone (3) are connected sequentially from bottom to top and are coaxially arranged; the horizontal cross-sectional area of ​​the fluidization zone (1), the transition zone (2) and the settling zone (3) increases sequentially. The first water inlet (7), ozone inlet (8) and biofilm-containing activated carbon inlet are located at the bottom of the fluidization zone (1); the first air outlet (10) is located at the top of the settling zone (3); and the biofilm-containing activated carbon inlet is located above the ozone inlet (8). The first water outlet (12) is located at the upper part of the solid-liquid separation zone (4); The bottom of the solid-liquid separation zone (4) is also provided with a slag discharge port (13).

3. The apparatus according to claim 1, characterized in that, Inside the biological activated carbon reactor (II), the biofilm-removing activated carbon inlet and the second water outlet (17) are respectively located at the upper part of the biological activated carbon reactor (II); the second gas outlet (16) is located at the top of the biological activated carbon reactor (II); the second water inlet (15), the oxygen-containing gas inlet (14), and the biofilm-containing activated carbon outlet are respectively located at the lower part of the biological activated carbon reactor (II); The biofilm-free activated carbon inlet of the bio-activated carbon reactor (II) is connected to the biofilm-free activated carbon outlet of the settling zone (3) through an upper packing pipe (5); the biofilm-containing activated carbon outlet of the bio-activated carbon reactor (II) is connected to the biofilm-containing activated carbon inlet of the fluidization zone (1) through a lower packing pipe (6).

4. The apparatus according to claim 3, characterized in that, The horizontal position of the biofilm-de-biofilm activated carbon outlet of the catalytic oxidation reactor (I) is higher than that of the biofilm-de-biofilm activated carbon inlet of the biological activated carbon reactor (II), so that the upper packing tube (5) is inclined downward from the biofilm-de-biofilm activated carbon outlet to the biofilm-de-biofilm activated carbon inlet. The biofilm-containing activated carbon outlet of the bio-activated carbon reactor (II) is positioned higher than the biofilm-containing activated carbon inlet of the catalytic oxidation reactor (I), so that the lower packing tube (6) is inclined downward from the biofilm-containing activated carbon outlet to the biofilm-containing activated carbon inlet.

5. The apparatus according to claim 4, characterized in that, The bottom of the bio-activated carbon reactor (II) is located above the bottom of the fluidization zone (1) of the catalytic oxidation reactor (I), and the top of the bio-activated carbon reactor (II) is located below the top of the settling zone (3) of the catalytic oxidation reactor (I).

6. The apparatus according to claim 1, characterized in that, The device also includes an ozone generator (III), the ozone outlet of which is connected to the ozone inlet (8) of the catalytic oxidation reactor (I).

7. The apparatus according to claim 2, characterized in that, The catalytic oxidation reactor (I) includes an inner shell and an outer shell arranged in a vertical direction. The inner shell includes a cylindrical fluidization zone (1), a transition zone (2) and a cylindrical settling zone (3) connected sequentially from bottom to top. The diameter of the settling zone (3) is larger than the diameter of the fluidization zone (1). The transition zone (2) is formed into an inverted frustum shape. The outer shell is fitted outside the inner shell of the settling zone (3) and forms a cylindrical solid-liquid separation zone (4).

8. The apparatus according to claim 7, characterized in that, The bottom surface of the solid-liquid separation zone (4) is flush with the bottom surface of the sedimentation zone (3) in the horizontal direction; the top edge of the solid-liquid separation zone (4) is lower than the top edge of the sedimentation zone (3); The bio-activated carbon reactor (II) includes a cylindrical shell arranged in a vertical direction, and the diameter of the shell of the bio-activated carbon reactor (II) is larger than the diameter of the fluidization zone (1) and the transition zone (2).

9. The apparatus according to claim 7, characterized in that, The ratio of the top diameter of the transition zone (2) to the diameter of the fluidization zone (1) is 1.5 to 20:1; The height to diameter ratio of the fluidized zone (1) is 2~20:1; The height ratio of the transition zone (2) to the settlement zone (3) is 0.2~5:1; The diameter ratio of the solid-liquid separation zone (4) to the sedimentation zone (3) is 1.2~5:

1.

10. The apparatus according to claim 9, characterized in that, The ratio of the top diameter of the transition zone (2) to the diameter of the fluidization zone (1) is 2 to 10:

1.

11. The apparatus according to claim 9, characterized in that, The ratio of the height to the diameter of the fluidized zone (1) is 5 to 10:

1.

12. The apparatus according to claim 9, characterized in that, The height ratio of the transition zone (2) to the settlement zone (3) is 0.5 to 2:

1.

13. The apparatus according to claim 9, characterized in that, The diameter ratio of the solid-liquid separation zone (4) to the sedimentation zone (3) is 1.5~3:

1.

14. A wastewater treatment method using ozone catalytic oxidation combined with biological activated carbon, wherein the method employs the apparatus described in any one of claims 1 to 13, characterized in that, Includes the following steps: S1. The wastewater containing organic matter, ozone, and activated carbon carrier are introduced into the fluidized zone (1) of the catalytic oxidation reactor (I) for fluidized catalytic oxidation reaction. The resulting reaction mixture is introduced into the sedimentation zone (3) and separated by the three-phase separator (9) to obtain debiofilm activated carbon, first gas, and solid-liquid mixture. The solid-liquid mixture is then introduced into the solid-liquid separation zone (4) for solid-liquid separation to obtain first treated water and residue. S2. The first treated water from the catalytic oxidation reactor (I), the debiofilm activated carbon, and the oxygen-containing gas are introduced into the biological activated carbon reactor (II), so that the remaining organic matter in the first treated water and the sewage treatment bacteria in the biological activated carbon reactor (II) undergo an aerobic biochemical reaction under aeration conditions to obtain purified water, biofilm activated carbon, and a second gas; wherein the oxygen-containing gas includes the first gas from the catalytic oxidation reactor (I). S3. The biofilm-containing activated carbon from the bio-activated carbon reactor (II) is returned to the fluidization zone (1) of the catalytic oxidation reactor (I) to contact the wastewater to be treated and ozone, thereby washing and regenerating the biofilm-containing activated carbon.

15. The method according to claim 14, characterized in that, In step S1, based on the 1L of wastewater to be treated introduced, the flow rate of ozone is 50~20000mL / min; Based on the amount of wastewater introduced in 1L, the amount of activated carbon carrier introduced is 50~5000g; The wastewater to be treated has a residence time of 0.05~5h in the fluidization zone (1) and a reaction temperature of 10~40℃; The COD of the wastewater to be treated is 60~150 mg / L, and the BOD / COD ratio is less than 0.

25.

16. The method according to claim 15, characterized in that, In step S1, based on the 1L of wastewater to be treated introduced, the flow rate of ozone is 200~5000mL / min.

17. The method according to claim 15, characterized in that, Based on the amount of wastewater introduced into 1L of the wastewater to be treated, the amount of activated carbon carrier introduced is 100~2000g.

18. The method according to claim 15, characterized in that, The wastewater to be treated has a residence time of 0.1 to 2 hours in the fluidization zone (1) and a reaction temperature of 15 to 30°C.

19. The method according to claim 14, characterized in that, In step S2, based on the 1L of wastewater to be treated introduced, the dissolved oxygen in the biological activated carbon reactor (II) is 1~8mg; Based on the amount of 1L of wastewater to be treated introduced, the amount of activated carbon introduced for biofilm removal is 2~500g; The first treated water has a residence time of 0.2 to 12 hours in the biological activated carbon reactor (II); the reaction temperature is 10 to 40°C.

20. The method according to claim 19, characterized in that, In step S2, based on the 1L of wastewater to be treated introduced, the dissolved oxygen in the biological activated carbon reactor (II) is 2~4mg.

21. The method according to claim 19, characterized in that, Based on the amount of wastewater introduced into 1L of the wastewater to be treated, the amount of activated carbon introduced for biofilm removal is 5~200g.

22. The method according to claim 19, characterized in that, The first treated water has a residence time of 1-6 hours in the biological activated carbon reactor (II); the reaction temperature is 20-35°C.

23. The method according to claim 14, characterized in that, The activated carbon carrier has an average particle size of 60-200 mesh, an average pore size of 0.01-10 nm, and a total pore volume of 0.001-0.5 cm³. 3 / g, BET specific surface area is 1~1000m² 2 / g.

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