Sewage treatment device for double-membrane concentrated water

Abstract

The sewage treatment device comprises a UASB (Upflow Anaerobic Sludge Blanket) anaerobic reactor, a water outlet pipeline of the UASB anaerobic reactor is connected with a water inlet pipeline of a biological contact oxidation pond, and a water outlet pipeline of the biological contact oxidation pond is connected with a water inlet pipeline of a secondary sedimentation tank; the secondary sedimentation tank is connected with the ozone-biological activated carbon device, the ozone-biological activated carbon device consists of an ozone contact tower and a biological activated carbon filter tank, a water outlet pipeline of the secondary sedimentation tank is connected with a water inlet pipeline of the ozone contact tower, and a water outlet pipeline of the ozone contact tower is connected with a water inlet pipeline of the biological activated carbon filter tank. The UASB anaerobic reactor, the biological contact oxidation tank, the secondary sedimentation tank and the ozone-biological activated carbon device are arranged, so that the sewage treatment process flow is simple, an external carbon source is not needed, and the capital construction cost and the operation cost are low.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment devices, in particular to a sewage treatment device for double-membrane concentrated water. Background Art

[0002] In recent years, due to water resource shortages, many sewage treatment plants have implemented advanced treatment of their effluent for reuse. Common water reuse technologies include reverse osmosis (RO), electrodialysis (ED), nanofiltration (NF), vapor compression (VC), multi-effect evaporation (MED), and multi-stage flash (MSF). The proportion of recycled water produced using each technology is 44% for RO, 40% for MSF, and 26% for other technologies. This indicates that RO is effective in removing inorganic salts and some organic matter, resulting in high-quality effluent and lower investment and operating costs than VC, MED, and MSF. The dual-membrane process, consisting of ultrafiltration and reverse osmosis, has become an important method for wastewater / sewage reuse, with effluent meeting high-level reuse standards, even reaching drinking water standards.

[0003] An increasing number of companies are adopting the ultrafiltration-reverse osmosis dual-membrane process for wastewater reuse and treatment to reduce wastewater discharge. However, this dual-membrane process only produces approximately 40-50% of clean water for reuse, leaving the remaining 50-60% of concentrate requiring further treatment to meet discharge standards. This system's key advantages include stable effluent quality, low system acid and alkali consumption, and high fresh water consumption. The recovery rate of a single-stage reverse osmosis process is generally around 75%, meaning that 25% of the fresh water is discharged as reverse osmosis concentrate.

[0004] While the dual-membrane process is widely used in wastewater recycling, the discharge of process brine is gradually coming under control. Failure to recycle it not only wastes water resources but also has adverse environmental impacts. The treatment of RO brine has always been one of the challenges of the process. RO brine, characterized by high COD, high salinity, and high chroma, is difficult to handle. Removal of organic matter is a key step in the subsequent treatment of this brine. Based on the characteristics of organic matter and testing, the organic matter in RO brine is difficult to biodegrade again, making it challenging to use a single biochemical treatment process.

[0005] At present, the main problems of concentrated water recovery are:

[0006] 1) Easy to scale. Due to the selective permeability of reverse osmosis, on the one hand, the permeability of CO2 is almost 100%, which leads to an increase in the pH value of the concentrated water side. On the other hand, Ca 2+ The transmittance is almost zero, resulting in the measurement of Ca in concentrated water. 2+ The concentration is about 4 times that of the influent, and the combined effect of the two easily causes CaCO3 to precipitate;

[0007] 2) Easy to foul and clog. Due to the interception effect of reverse osmosis on organic matter and colloids, organic matter and colloids accumulate on the concentrated water side. If they are not effectively controlled, they will also cause fouling and clogging of the reverse osmosis membrane;

[0008] 3) Easy to pollute. When the reverse osmosis device is running, various nutrients in the water are enriched, making it very easy for microorganisms to breed on the concentrated water side. If there is no effective control, it will also cause biological pollution of the reverse osmosis membrane.

[0009] Therefore, in order to solve the above problems, a sewage treatment device for double-membrane concentrated water is proposed. Utility Model Content

[0010] The utility model aims to provide a sewage treatment device for double-membrane concentrated water, comprising a UASB anaerobic reactor, wherein the outlet pipe of the UASB anaerobic reactor is connected to the inlet pipe of a biological contact oxidation tank, the outlet pipe of the biological contact oxidation tank is connected to the inlet pipe of a secondary sedimentation tank, the secondary sedimentation tank is connected to an ozone-biological activated carbon device, the ozone-biological activated carbon device consists of an ozone contact tower and a biological activated carbon filter, the outlet pipe of the secondary sedimentation tank is connected to the inlet pipe of the ozone contact tower, and the outlet pipe of the ozone contact tower is connected to the inlet pipe of the biological activated carbon filter.

[0011] Furthermore, the UASB anaerobic reactor is used to perform anaerobic biological treatment on the double-membrane concentrated water. Through the oxidation action of anaerobic microorganisms, the refractory organic matter in the concentrated water is degraded into small molecular organic matter, inorganic matter, and CH4 through hydrolysis, acidification, hydrogen and acid production, and methane production. The generated biogas is comprehensively utilized after gas-water separation, and the treated water enters the biological contact oxidation tank.

[0012] Furthermore, the biological contact oxidation tank is used for aerobic biological treatment. After the effluent from the UASB anaerobic reactor enters the biological contact oxidation tank, the microorganisms in the large number of biofilms adhered to the composite filler degrade the pollutants in the wastewater, and at the same time further remove the nitrogen in the sewage. The effluent enters the secondary sedimentation tank for solid-liquid separation and then enters the deep treatment device.

[0013] Furthermore, the ozone-biological activated carbon treatment refers to the effluent from the secondary sedimentation tank entering the ozone-biological activated carbon system, using the oxidizing ability of ozone to degrade long-chain, large-molecule organic matter in the wastewater, using activated carbon to adsorb dissolved organic matter in the water, enriching microorganisms in the water, and removing suspended matter.

[0014] Furthermore, the UASB anaerobic reactor adopts medium-temperature anaerobic fermentation, with the optimum reaction temperature being 30-38°C and the volume load being 3kg-8kg COD Cr / (m 3 ·d).

[0015] Furthermore, the dissolved oxygen concentration in the biological contact oxidation pond is 2-4 mg / L, the combined filler filling rate is 50-70%, and the sludge concentration is 2.5-4.0 kg MLSS / L.

[0016] Furthermore, the sludge return ratio R in the sludge return system of the secondary sedimentation tank is 30-50%.

[0017] Furthermore, the ozone contact tower is a cylindrical tower structure with a height-to-diameter ratio of 6-8, an ozone contact time of 5-10 minutes, and an ozone dosage of 0.5-1 mg / L.

[0018] Furthermore, the filling height of the activated carbon in the biological activated carbon filter is 1.5-2m, the filling density is 480-500g / L, the filtration rate of the filter is 8-10m / h, and the contact time is 10-15min.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The utility model sets up UASB anaerobic reactor, biological contact oxidation tank, secondary sedimentation tank and ozone-biological activated carbon device, which has simple sewage treatment process, no need for external carbon source, and low capital construction cost and operation cost.

[0021] 2. The utility model is easy to operate and manage, and there is no problem of sludge bulking. Therefore, there is no need to frequently monitor the sludge situation in the reaction tank and change the operating parameters, making daily operation and management simpler.

[0022] 3. The utility model has low operating energy consumption and adopts UASB anaerobic reactor to treat double-membrane concentrated water. The sludge concentration in UASB is high. The refractory organic matter in the concentrated water is degraded into small molecular organic matter, inorganic matter and CH4 through the oxidation action of anaerobic microorganisms. The use of UASB technology can greatly save energy consumption.

[0023] 4. The utility model adopts biological contact oxidation process, which has a higher volumetric load; it has strong adaptability to sudden changes in water quality and quantity, is resistant to shock loads, has a small amount of residual sludge, does not have sludge expansion problems, reduces sludge treatment costs, and is easy to operate and manage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the utility model;

[0025] Figure 2 It is a flow chart of the utility model.

[0026] The reference numerals and names in the figures are as follows:

[0027] 1. UASB anaerobic reactor; 2. Biological contact oxidation tank; 3. Secondary sedimentation tank; 4. Ozone-biological activated carbon device; 5. Ozone contact tower; 6. Biological activated carbon filter. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] As attached Figure 1 、 2 As shown, the utility model provides a sewage treatment device for double-membrane concentrated water, including a UASB anaerobic reactor 1, the outlet pipe of the UASB anaerobic reactor 1 is connected to the inlet pipe of the biological contact oxidation tank 2, the outlet pipe of the biological contact oxidation tank 2 is connected to the inlet pipe of the secondary sedimentation tank 3, the secondary sedimentation tank 3 is connected to the ozone-biological activated carbon device 4, the ozone-biological activated carbon device 4 is composed of an ozone contact tower 5 and a biological activated carbon filter 6, the outlet pipe of the secondary sedimentation tank 3 is connected to the inlet pipe of the ozone contact tower 5, and the outlet pipe of the ozone contact tower 5 is connected to the inlet pipe of the biological activated carbon filter 6.

[0030] Specifically, a combined biological filler is provided inside the biological contact oxidation pond 2 , and an aeration device is provided at the bottom of the biological contact oxidation pond 2 .

[0031] Specifically, the UASB anaerobic reactor adopts medium-temperature anaerobic fermentation, with the optimal reaction temperature being 30-38°C and the volume load being 3kg-8kg COD Cr / (m 3 ·d).

[0032] Specifically, the dissolved oxygen concentration in the biological contact oxidation pond is 2-4 mg / L, the combined filler filling rate is 50-70%, and the sludge concentration is 2.5-4.0 kg MLSS / L.

[0033] Specifically, the sludge return ratio R in the sludge return system of the secondary sedimentation tank is 30-50%.

[0034] Specifically, the ozone contact tower is a cylindrical tower structure with a height-to-diameter ratio of 6-8, an ozone contact time of 5-10 minutes, and an ozone dosage of 0.5-1 mg / L.

[0035] Specifically, the filling height of the activated carbon in the biological activated carbon filter is 1.5-2m, the filling density is 480-500g / L, the filtration rate of the filter is 8-10m / h, and the contact time is 10-15min.

[0036] Working principle: After being collected, the double-membrane concentrated water enters the UASB anaerobic reactor 1, where the refractory organic matter in the concentrated water is broken down and decomposed into small-molecule organic matter through the action of anaerobic granular sludge, thereby removing some organic matter and improving the biodegradability of the wastewater. The effluent from the UASB anaerobic reactor 1 enters the biological contact oxidation tank 2 for aerobic treatment, where the pollutants in the wastewater are degraded by the microorganisms in the large number of biofilms adhering to the composite fillers. The effluent from the biological contact oxidation tank 2 enters the secondary sedimentation tank 3 for solid-liquid separation and then enters the ozone-biological activated carbon device 4. The ozone-biological activated carbon device 4 uses the oxidizing ability of ozone to degrade the long-chain and large-molecule organic matter in the wastewater, and uses activated carbon to adsorb the dissolved organic matter in the water, enriches the microorganisms in the water, and removes the suspended matter, so that the effluent finally meets the discharge standards.

[0037] Experimental Example 1:

[0038] The quality of the concentrated water effluent from the ultrafiltration reverse osmosis system of a sewage treatment plant in an industrial park is COD Cr 200-220mg / L, BOD 35-60mg / L, pH 6-9, turbidity 8-10NTU, wastewater volume 5000m 3 / d.

[0039] The double-membrane concentrated water treatment device of the present invention is used for treatment, which includes the following steps:

[0040] (1) The collected double membrane concentrated water enters the UASB anaerobic reactor 1, the anaerobic temperature of the UASB anaerobic reactor 1 is 33-35 ° C, and the volume load is 3 kg COD Cr / (m 3 d) Anaerobic biological treatment to remove most of the organic matter through oxidation of anaerobic granular sludge and produce biogas;

[0041] (2) The effluent from the UASB anaerobic reactor 1 enters the biological contact oxidation tank 2 for aerobic biological treatment. The dissolved oxygen concentration in the biological contact oxidation tank is 3 mg / L, the filling rate of the composite filler is 60%, and the sludge concentration is 3.0 kg MLSS / L. The pollutants in the wastewater are removed by the action of microorganisms in the large amount of biofilm adhered to the composite biological filler;

[0042] (3) The effluent from the biological contact oxidation tank 2 enters the secondary sedimentation tank 3 for solid-liquid separation, and the sludge return ratio of the secondary sedimentation tank is 40%;

[0043] (4) The effluent from the secondary sedimentation tank 3 enters the ozone-biological activated carbon device 4, wherein the height-to-diameter ratio of the ozone contact tower 5 is 6, the ozone contact time is 5 minutes, and the ozone dosage is 0.5 mg / L; the filling height of the activated carbon in the biological activated carbon filter 6 is 1.5 meters, the filling density is 480 g / L, the filtration rate of the filter is 8 meters / hour, and the contact time is 10 minutes. The effluent from the ozone-biological activated carbon device 4 further removes the refractory organic matter and meets the reuse water standard.

[0044] After treatment, the effluent COD Cr <50mg / L, BOD<10mg / L, turbidity<5NTU, meeting the requirements of "Water Quality for Industrial Water Use in Municipal Wastewater Recycling" GB / T19923-200.

[0045] Experimental Example 2:

[0046] The quality of concentrated water produced by the double membrane process in a paper mill wastewater treatment system is COD Cr 230-250mg / L, BOD is 40-68mg / L, pH is 6-9, turbidity is 9-14NTU, and the wastewater volume is 3000m 3 / d.

[0047] The double-membrane concentrated water treatment device of the present invention is used for treatment, which includes the following steps:

[0048] (1) The collected double membrane concentrated water enters the UASB anaerobic reactor 1, the anaerobic temperature of the UASB anaerobic reactor 1 is 33-35 ° C, and the volume load is 3.5 kg COD Cr / (m 3 d) Anaerobic biological treatment to remove most of the organic matter through oxidation of anaerobic granular sludge and produce biogas;

[0049] (2) The effluent from the UASB anaerobic reactor 1 enters the biological contact oxidation tank 2 for aerobic biological treatment. The dissolved oxygen concentration in the biological contact oxidation tank is 3.5 mg / L, the filling rate of the composite filler is 65%, and the sludge concentration is 3.5 kg MLSS / L. The pollutants in the wastewater are removed by the action of microorganisms in the large amount of biofilm adhered to the composite biological filler.

[0050] (3) The effluent from the biological contact oxidation tank 2 enters the secondary sedimentation tank 3 for solid-liquid separation, and the sludge return ratio of the secondary sedimentation tank is 45%.

[0051] (4) The effluent from the secondary sedimentation tank 3 enters the ozone-biological activated carbon device 4. The height-to-diameter ratio of the ozone contact tower 5 in the ozone-biological activated carbon device 4 is 7, the ozone contact time is 8 minutes, and the ozone dosage is 0.7 mg / L. The filling height of the activated carbon in the biological activated carbon filter is 1.8 m, the filling density is 490 g / L, the filtration rate of the filter is 9 m / h, and the contact time is 12 minutes. After the refractory organic matter is further removed by the ozone-biological activated carbon device 4, the effluent meets the reuse water standard.

[0052] After treatment, the effluent COD Cr <40mg / L, BOD<10mg / L, turbidity<5NTU, meeting the requirements of "Water Quality for Industrial Water Use in Municipal Wastewater Recycling" GB / T19923-2005.

[0053] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc. should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in this utility model based on the specific circumstances.

Claims

1. A sewage treatment device for concentrated water using a double membrane process, comprising a UASB anaerobic reactor (1), characterized in that: The outlet pipe of the UASB anaerobic reactor (1) is connected to the inlet pipe of the biological contact oxidation tank (2), the outlet pipe of the biological contact oxidation tank (2) is connected to the inlet pipe of the secondary sedimentation tank (3), the secondary sedimentation tank (3) is connected to the ozone-biological activated carbon device (4), and the ozone-biological activated carbon device (4) is composed of an ozone contact tower (5) and a biological activated carbon filter (6).

2. A sewage treatment device for concentrated water using a double membrane process according to claim 1, characterized in that: The water outlet pipe of the secondary sedimentation tank (3) is connected to the water inlet pipe of the ozone contact tower (5).

3. A sewage treatment device for concentrated water using a double membrane process according to claim 1, characterized in that: The water outlet pipe of the ozone contact tower (5) is connected to the water inlet pipe of the biological activated carbon filter (6).

4. A sewage treatment device for concentrated water using a double membrane process according to claim 1, characterized in that: A combined biological filler is provided inside the biological contact oxidation pond (2), and an aeration device is provided at the bottom of the biological contact oxidation pond (2).

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