Coal chemical biochemical tail water total organic carbon removal water treatment method

Abstract

The present application relates to the technical field of water treatment, in particular to a water treatment method for removing total organic carbon from coal chemical biochemical tail water, which is characterized by the following steps: performing advanced oxidation treatment on the difficult-to-degrade biochemical tail water to improve the biodegradability, controlling the total organic carbon content of the effluent by deep biochemical system treatment, performing deep oxidation on the effluent from the deep biochemical system to oxidize the oxidizable molecular groups of the organic matter into carboxyl groups, performing deep adsorption on the effluent after the deep oxidation to remove difficult-to-oxidize organic matter and other small-molecule organic matter, and then entering a negatively charged nanofiltration membrane system to remove multivalent ion type organic matter in the water by using the surface electric charging effect of the membrane and remove some macromolecules through the nanoscale pore diameter of the nanofiltration membrane, and finally removing salt and a small amount of total organic carbon through a reverse osmosis system. The present application controls the total organic carbon content from the source, removes the total organic carbon through synergy and complementation, and solves the problem that the coal chemical biochemical tail water cannot meet the water requirement of high-temperature and high-pressure boilers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a water treatment method for removing total organic carbon from coal chemical industry biochemical tail water. BACKGROUND

[0002] Coal chemical industry wastewater is generally divided into easily degradable coal chemical industry wastewater and hardly degradable coal chemical industry wastewater, and after physical, chemical and biochemical treatment, the biochemical tail water is divided into hardly degradable coal chemical industry biochemical tail water and degradable coal chemical industry biochemical tail water. When coal chemical industry is produced on a large scale, not only a large amount of production wastewater is generated, but also a large amount of high-temperature and high-pressure steam is consumed. When the high-temperature and high-pressure boiler water is gasified at high temperature, the organic matter in the boiler water will react with water to generate hydrogen gas, and the accumulation of hydrogen gas will cause the boiler to explode. Therefore, the water entering the high-temperature and high-pressure boiler must meet the requirement that the total organic carbon (TOC) is less than 0.5 mg / L. Although the organic matter in raw water is generally low, the total organic carbon (TOC) of the effluent of the reverse osmosis treatment system matched with the boiler can be less than 0.5 mg / L. However, because of the extreme water shortage in many coal regions in the northwest, it is necessary to treat the biochemical tail water into water with total organic carbon (TOC) less than 0.5 mg / L.

[0003] The composition of coal chemical industry wastewater is complex, and the composition of its biochemical tail water is even more complex. The technology for removing organic matter from coal chemical industry biochemical tail water generally includes activated carbon adsorption and nanofiltration membrane removal, and reverse osmosis membrane is mainly used for desalination. Activated carbon adsorption has strong adsorption capacity for organic matter with poor solubility, poor hydrophilicity and weak polarity (such as benzene, phenol, petroleum and petroleum products), weak adsorption capacity for organic matter with high solubility, strong hydrophilicity and strong polarity, and poor removal effect. The main removal is for organic matter with weak polarity, such as benzene, phenol, petroleum and petroleum products. Nanofiltration membrane utilizes Donnan effect, has good removal effect on macromolecules and multivalent ion organic matter larger than the pore size of nanofiltration membrane, and low removal rate on monovalent ion organic matter and non-ionic organic matter; nanofiltration membrane basically does not intercept monovalent ions, and has certain interception on multivalent ions according to the pore size and performance of nanofiltration membrane. Due to the respective defects of activated carbon adsorption and nanofiltration membrane, the coal chemical industry biochemical tail water is currently difficult to be treated to have total organic carbon (TOC) less than 0.5 mg / L, and cannot meet the water requirement of high-temperature and high-pressure boiler (GB / T1576-2018 Industrial Boiler Water Quality). Therefore, the coal chemical industry biochemical tail water can only be used for low-end use, such as circulating water, greening, toilet flushing, river water replenishment, etc. The coal chemical industry biochemical tail water treatment is faced with the problems of low resource utilization rate and water resource waste. SUMMARY

[0004] The present application aims to provide a water treatment method for removing total organic carbon from biochemical tail water, so as to solve the problems of low resource utilization rate and water resource waste in the current coal chemical industry biochemical tail water treatment.

[0005] In order to achieve the above-mentioned purpose, the present application provides a water treatment method for removing total organic carbon from coal chemical industry biochemical tail water, which classifies the coal chemical industry biochemical tail water according to the biodegradability B / C ratio (5-day biochemical oxygen demand / chemical oxygen demand) from the source, and the degradable biochemical tail water with a B / C ratio greater than 0.3 is directly introduced into a deep biochemical system, the non-degradable biochemical tail water with a B / C ratio less than 0.3 is subjected to advanced oxidation treatment to improve the biodegradability, and the B / C ratio is increased to 0.3 or more before being introduced into the deep biochemical system, the content of total organic carbon (TOC) in the effluent is stably controlled after the treatment of the deep biochemical system, and the total organic carbon (TOC) in the effluent is less than 25 mg / L; the effluent from the deep biochemical system is subjected to deep oxidation, the organic oxidizable molecular groups (such as hydroxyl, aldehyde group, ketone group, phenolic hydroxyl, methylene, etc.) are oxidized into carboxyl, and the organic matter is formed into alkyl polycarboxylic acid (R(COOH)n) as much as possible, and the deep oxidation removal rate of total organic carbon (TOC) is between 50% and 70%; the effluent after the deep oxidation is introduced into a deep adsorption system, the non-oxidizable organic matter, benzene, petroleum and petroleum products, monovalent carboxylic acid and other small molecular organic matters are removed, and then the effluent is introduced into a negatively charged nanofiltration membrane system, the multivalent ion type organic matter in the water is removed through the membrane surface electric channel effect of the negatively charged nanofiltration membrane, and some macromolecules are removed through the nanoscale pore diameter of the nanofiltration membrane; the deep oxidation system, the deep adsorption system and the deep separation system are complementary to each other, and finally the salt and a small amount of total organic carbon are removed through a reverse osmosis system, so that the total organic carbon (TOC) in the effluent can be less than 0.5 mg / L.

[0006] According to the above idea, the present application provides a water treatment method for removing total organic carbon from coal chemical industry biochemical tail water, which adopts the following technical scheme, and the treatment steps are as follows:

[0007] (1) The tail water after the biochemical treatment of the coal chemical industry wastewater is divided into non-degradable coal chemical industry biochemical tail water and degradable coal chemical industry biochemical tail water, and the non-degradable coal chemical industry biochemical tail water is further subjected to advanced oxidation system treatment;

[0008] (2) The effluent after the treatment of the non-degradable coal chemical industry biochemical tail water by the advanced oxidation system and the degradable coal chemical industry biochemical tail water are mixed and introduced into a deep biochemical system for treatment, the total organic carbon (TOC) in the effluent is less than 25 mg / L, and is preferably 15-20 mg / L;

[0009] (3) The effluent of step (2) is introduced into a deep oxidation system for treatment;

[0010] (4) The effluent of step (3) is introduced into a deep adsorption system;

[0011] (5) The effluent of step (4) is introduced into a deep separation system for treatment, the total organic carbon (TOC) in the effluent is less than 1 mg / L, and is preferably 0.6-0.8 mg / L;

[0012] (6) the concentrated phase water of step (5) is returned to step (2) to be treated in the deep biochemical system;

[0013] (7) the effluent of step (5) is treated in a reverse osmosis system, and the total organic carbon (TOC) of the effluent is less than 0.5 mg / L, preferably 0.3-0.5 mg / L; the concentrated phase water of the reverse osmosis system is treated in a desalination system.

[0014] According to the above step (1), the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical industry biochemical tail water is greater than 0.3, and the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the non-degradable coal chemical industry biochemical tail water is less than 0.3. The two kinds of biochemical tail water can be mixed in any proportion according to the actual production situation.

[0015] According to the above step (1), the total organic carbon (TOC) of the degradable coal chemical industry biochemical tail water is less than 30 mg / L, preferably 25-30 mg / L; and the total organic carbon (TOC) of the non-degradable coal chemical industry biochemical tail water is less than 150 mg / L, preferably 80-120 mg / L.

[0016] According to the above step (1), the advanced oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide-ozone combined catalytic oxidation system, preferably a hydrogen peroxide-ozone combined catalytic oxidation system.

[0017] According to the above step (1), the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the non-degradable coal chemical industry biochemical tail water after being treated by the advanced oxidation system is greater than 0.3.

[0018] According to the above step (2), the deep biochemical system is an anoxic-aerobic-biological aerated filter (AO-BAF) system or an anoxic-aerobic-microfiltration membrane (AO-MBR) system.

[0019] According to the above step (3), the deep oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide-ozone combined catalytic oxidation system, and the total organic carbon (TOC) removal rate of the effluent after being treated by the deep oxidation system is 50%-70%, preferably 60%.

[0020] According to the above step (4), the deep adsorption system is a macroporous adsorption resin system or an activated carbon adsorption system, preferably an activated carbon adsorption system.

[0021] According to the above step (5), the deep separation system is a negatively charged nanofiltration membrane system, and the filtration precision is between 150-600 daltons, preferably 300-400 daltons.

[0022] According to the above processing step (7), the reverse osmosis system is a desalination reverse osmosis membrane filtration system, and the selected reverse osmosis membrane material is cellulose acetate, aromatic polyamide, chitosan membrane, polyphenyl reverse osmosis membrane or composite membrane made of the above materials.

[0023] Further, according to the above processing steps, the residence time of the anoxic-aerobic-microfiltration membrane (AO-MBR) system is 12-48 hours, preferably 24 hours; the residence time of the anoxic-aerobic-biological aerated filter (AO-BAF) system is 12-48 hours, preferably 24 hours.

[0024] Further, according to the above processing steps, the activated carbon is coal-based granular carbon, wooden activated carbon, shell activated carbon, synthetic resin activated carbon, rubber / plastic activated carbon, regenerated granular activated carbon or bamboo charcoal, preferably shell activated carbon or regenerated granular activated carbon; the macroporous adsorption resin is non-polar, weakly polar, moderately polar or polar resin, preferably polar resin.

[0025] Further, according to the above processing steps, the negatively charged nanofiltration membrane material is polyamide (PA), sulfonated polysulfone (SPS), polyvinyl alcohol (PVA), sulfonated polyether sulfone (SPES), cellulose acetate (CA), polysulfone (PS), polyether ether ketone (PEEK) or composite membrane formed by the above materials, preferably polyamide (PA).

[0026] Further, according to the above processing steps, the activated carbon is mesoporous activated carbon or macroporous activated carbon.

[0027] The present application realizes the innovation of the technology by performing advanced oxidation on the biodegradable coal chemical biochemical tail water, and performing deep biochemical treatment on the degradable coal chemical biochemical tail water, and then performing a series of steps such as deep oxidation, deep adsorption, deep separation and reverse osmosis.

[0028] The present application has the following advantages: the present application controls the total organic carbon content from the source, and the various process systems in the treatment process are complementary, especially the combination of deep oxidation, deep adsorption and negatively charged nanofiltration membrane, which strongly removes the total organic carbon, and finally removes salt and total organic carbon through the reverse osmosis system, and the effluent is stable to reach total organic carbon (TOC) less than 0.5mg / L. The present application solves the problem that the coal chemical biochemical tail water cannot be treated to total organic carbon (TOC) less than 0.5mg / L, and cannot meet the water requirement of high temperature and high pressure boiler (GB / T1576-2018 industrial boiler water quality), solves the problem of low water resource utilization rate of coal chemical enterprises, and avoids water resource waste, is a green and environmentally friendly technology. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1This is a schematic flowchart of an embodiment of the water treatment method for removing total organic carbon from coal chemical and biochemical tailwater of the present invention.

[0030] Figure 2 This is a block diagram of an ozone catalytic oxidation system;

[0031] Figure 3 Block diagram of hydrogen peroxide-ozone combined catalytic system;

[0032] Figure 4 A block diagram of anoxic-aerobic-aerated biological filter system;

[0033] Figure 5 Block diagram of an anoxic-aerobic-microfiltration membrane system;

[0034] Figure 6 Block diagrams for deep separation and reverse osmosis systems. Detailed Implementation

[0035] The following detailed description illustrates the specific implementation method:

[0036] Example 1

[0037] like Figures 1-6 As shown, a system and method for treating coal chemical biochemical effluent to remove total organic carbon is disclosed. The system employs a sequential arrangement of an advanced oxidation system, a deep biochemical system, a deep oxidation system, a deep adsorption system, a deep separation system, and a reverse osmosis system.

[0038] Advanced oxidation systems are used to further oxidize and treat recalcitrant coal chemical and biochemical wastewater.

[0039] The advanced biological treatment system is used to mix the effluent from the advanced oxidation system with the biodegradable coal chemical biochemical tailwater for further biological treatment.

[0040] A deep oxidation system is used to oxidize the effluent from a deep biological treatment system.

[0041] A deep adsorption system is used to adsorb and treat the effluent from a deep oxidation system.

[0042] The deep separation system is used to separate and treat the effluent from the deep adsorption system and send the resulting concentrated phase water into the deep biological treatment system.

[0043] The reverse osmosis system is used to treat the effluent from the deep separation system by reverse osmosis. The concentrated phase water obtained from the reverse osmosis system enters the desalination system.

[0044] The method includes the following steps:

[0045] (1) the coal chemical wastewater after physical, chemical and biochemical treatment is divided into non-degradable coal chemical biochemical tail water and degradable coal chemical biochemical tail water, the non-degradable coal chemical biochemical tail water is further treated by a high-level oxidation system, wherein the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical biochemical tail water is 0.4, the total organic carbon (TOC) is 30 mg / L, the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the non-degradable coal chemical biochemical tail water is 0.1, the total organic carbon (TOC) is 80 mg / L, the ratio of the two kinds of biochemical tail water is 2:1, the high-level oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide-ozone combined catalytic oxidation system, preferably a hydrogen peroxide-ozone combined catalytic oxidation system, and the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the effluent of the non-degradable coal chemical biochemical tail water after the high-level oxidation system treatment is 0.35;

[0046] (2) the effluent of the non-degradable coal chemical biochemical tail water after the high-level oxidation system treatment and the degradable coal chemical biochemical tail water are mixed into a deep biochemical system for treatment, the deep biochemical system is an anoxic-oxygenation-microfiltration membrane (AO-MBR) system, the residence time is 24 hours, wherein the anoxic tank is 6 hours, the oxygenation tank is 18 hours, and the total organic carbon (TOC) of the effluent is 20 mg / L;

[0047] (3) the effluent of step (2) is treated by a deep oxidation system, the deep oxidation system is an ozone catalytic oxidation system, and the total organic carbon (TOC) removal rate of the effluent after the deep oxidation system treatment is 60%;

[0048] (4) the effluent of step (3) is treated by a deep adsorption system, the deep adsorption system is an activated carbon adsorption system, and the activated carbon is preferably a macroporous activated carbon such as nutshell activated carbon;

[0049] (5) the effluent of step (4) is treated by a deep separation system, the deep separation system is a negatively charged nanofiltration membrane system, the filtration precision is 300-400 daltons, the material of the negatively charged nanofiltration membrane is preferably polyamide (PA), and the total organic carbon (TOC) of the effluent is 0.7 mg / L;

[0050] (6) the concentrated phase water of step (5) is returned to step (2) for treatment by the deep biochemical system;

[0051] (7) the effluent of step (5) is treated by a reverse osmosis system, the total organic carbon (TOC) of the effluent is 0.38 mg / L, and the concentrated phase water of the reverse osmosis system is treated by a desalination system, the reverse osmosis system is a desalination reverse osmosis membrane filtration system, and the material of the selected reverse osmosis membrane is aromatic polyamide.

[0052] Example 2

[0053] As Figures 1-6As shown, a system and method for removing total organic carbon from coal chemical biochemical tail water, the system module is the same as the embodiment, the method comprises the following steps:

[0054] (1) The coal chemical wastewater after physical and chemical and biochemical treatment is divided into non-degradable coal chemical biochemical tail water and degradable coal chemical biochemical tail water, and the non-degradable coal chemical biochemical tail water is further treated by a high-level oxidation system;

[0055] (2) The effluent after the non-degradable coal chemical biochemical tail water is treated by the high-level oxidation system and the degradable coal chemical biochemical tail water are mixed into a deep biochemical system for treatment, and the total organic carbon (TOC) of the effluent is 25 mg / L;

[0056] (3) The effluent of step (2) is treated by a deep oxidation system;

[0057] (4) The effluent of step (3) is treated by a deep adsorption system;

[0058] (5) The effluent of step (4) is treated by a deep separation system, and the total organic carbon (TOC) of the effluent is 0.8 mg / L;

[0059] (6) The concentrated phase water of step (5) is returned to step (2) and treated by a deep biochemical system;

[0060] (7) The effluent of step (5) is treated by a reverse osmosis system, and the total organic carbon (TOC) of the effluent is 0.4 mg / L, and the concentrated phase water of the reverse osmosis system is treated by a desalination system.

[0061] According to the above processing step (1), the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical biochemical tail water is 0.45, the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the non-degradable coal chemical biochemical tail water is 0.1, and the ratio of the two biochemical tail waters is 1.5:1.

[0062] The total organic carbon (TOC) of the degradable coal chemical biochemical tail water in the above processing step (1) is 30 mg / L, and the total organic carbon (TOC) of the non-degradable coal chemical biochemical tail water is 90 mg / L.

[0063] The high-level oxidation system in the above processing step (1) is an ozone catalytic oxidation system.

[0064] After the non-degradable coal chemical biochemical tail water in the above processing step (1) is treated by the high-level oxidation system, the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the effluent is 0.32.

[0065] The deep biochemical system in the above processing step (2) is an anoxic-aerobic-biological aerated filter (AO-BAF) system.

[0066] The deep oxidation system of the above processing step (3) is an ozone catalytic oxidation system, and the total organic carbon (TOC) removal rate of the effluent after the deep oxidation system treatment is 55%.

[0067] The deep adsorption system of the above processing step (4) is a macroporous adsorption resin system.

[0068] The deep separation system of the above processing step (5) is a negatively charged nanofiltration membrane system, and the filtration precision is 200-300 daltons.

[0069] The reverse osmosis system of the above processing step (7) is a desalination reverse osmosis membrane filtration system, and the selected reverse osmosis membrane material is a composite membrane made of cellulose acetate and aromatic polyamide material.

[0070] The anoxic-aerobic-biological aerated filter (AO-BAF) system of the above processing step has a residence time of 28 hours, of which the anoxic tank is 6 hours, the aerobic tank is 18, and the biological aerated filter is 4 hours.

[0071] The macroporous adsorption resin of the above processing step is a macroporous polar resin.

[0072] The negatively charged nanofiltration membrane material of the above processing step is sulfonated polysulfone (SPS).

[0073] Example 3

[0074] As shown in Figures 1-6 , a system and method for removing total organic carbon from coal chemical biochemical tail water, the system module is the same as the embodiment, the method comprises the following steps:

[0075] (1) The tail water after the coal chemical wastewater is treated by physical and chemical and biochemical is divided into non-degradable coal chemical biochemical tail water and degradable coal chemical biochemical tail water, and the non-degradable coal chemical biochemical tail water is further treated by a high-level oxidation system;

[0076] (2) The effluent after the non-degradable coal chemical biochemical tail water is treated by the high-level oxidation system and the degradable coal chemical biochemical tail water are mixed and treated by a deep biochemical system, and the total organic carbon (TOC) of the effluent is 22 mg / L;

[0077] (3) The effluent of step (2) is treated by a deep oxidation system;

[0078] (4) The effluent of step (3) is treated by a deep adsorption system;

[0079] (5) The effluent of step (4) is treated by a deep separation system, and the total organic carbon (TOC) of the effluent is 1.0 mg / L;

[0080] (6) The concentrated phase water of step (5) is returned to step (2) and treated by a deep biochemical system;

[0081] (7) The effluent from step (5) is treated in a reverse osmosis system, and the total organic carbon (TOC) of the effluent is 0.5 mg / L. The concentrated water from the reverse osmosis system is treated in a desalination system.

[0082] The B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical industry biochemical tail water in the above treatment step (1) is 0.45, and the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the non-degradable coal chemical industry biochemical tail water is 0.1. The ratio of the two types of biochemical tail water is 1:1.

[0083] The total organic carbon (TOC) of the degradable coal chemical industry biochemical tail water in the above treatment step (1) is 28 mg / L, and the total organic carbon (TOC) of the non-degradable coal chemical industry biochemical tail water is 120 mg / L.

[0084] The advanced oxidation system in the above treatment step (1) is a hydrogen peroxide-ozone combined catalytic oxidation system.

[0085] After the non-degradable coal chemical industry biochemical tail water in the above treatment step (1) is treated by the advanced oxidation system, the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the effluent is 0.38.

[0086] The advanced biochemical system in the above treatment step (2) is an anoxic-oxygen-microfiltration membrane (AO-MBR) system, and the residence time of the anoxic-oxygen-microfiltration membrane (AO-MBR) system is 24 hours, including 8 hours in the anoxic tank and 16 hours in the aerobic tank.

[0087] The advanced oxidation system in the above treatment step (3) is an ozone catalytic oxidation system, and the total organic carbon (TOC) removal rate of the effluent after treatment by the advanced oxidation system is 65%.

[0088] The advanced adsorption system in the above treatment step (4) is an activated carbon adsorption system, and the activated carbon is regenerated granular activated carbon or mesoporous activated carbon.

[0089] The advanced separation system in the above treatment step (5) is a negatively charged nanofiltration membrane system, and the negatively charged nanofiltration membrane material is a composite membrane formed by polyamide (PA) and polyvinyl alcohol (PVA), with a filtration precision of 400-500 daltons.

[0090] The reverse osmosis system in the above treatment step (7) is a desalination reverse osmosis membrane filtration system, and the selected reverse osmosis membrane material is a composite membrane made of cellulose acetate and aromatic polyamide material.

[0091] The systems and devices mentioned in the above embodiments are mature technologies in the art, and those skilled in the art can make selections according to actual conditions, such as: the advanced oxidation system selects a hydrogen peroxide-ozone combined catalytic oxidation system, which includes a second catalytic oxidation tower and a second tail water inlet pipeline, a hydrogen peroxide inlet pipeline and a second ozone gas inlet pipeline connected thereto, wherein the second tail water inlet pipeline includes a water inlet pump and a buffer tank, the second ozone gas inlet pipeline includes a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device, and the hydrogen peroxide inlet pipeline includes a hydrogen peroxide storage tank and a hydrogen peroxide feeding pump.

[0092] The advanced biochemical system can be an anoxic-oxygenation-microfiltration membrane (AO-MBR) system, which includes a sewage lifting pump, a buffer tank, an anoxic tank, an oxygenation tank and a microfiltration membrane system arranged in sequence, the oxygenation tank is connected with an aeration device, a mixed liquor circulating pump and a sludge concentration device are arranged between the oxygenation tank and the anoxic tank, and the microfiltration membrane system is connected with a membrane cleaning and regeneration device; or an anoxic-oxygenation-biological aerated filter (AO-BAF) system, which includes a sewage lifting pump, a buffer tank, an anoxic tank, an oxygenation tank and a biological aerated filter arranged in sequence, the oxygenation tank and the biological aerated filter are provided with an aeration device, and a mixed liquor circulating pump and a sludge concentration device are arranged between the oxygenation tank and the anoxic tank.

[0093] The advanced oxidation system can be an ozone catalytic oxidation system, which includes a first catalytic oxidation tower and a first tail water inlet pipeline and a first ozone gas inlet pipeline connected thereto, wherein the first tail water inlet pipeline includes a water inlet pump and a buffer tank, the first ozone gas inlet pipeline includes a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device, and the vacuum adsorption oxygen generator, the ozone generator and the advanced oxidation system are shared.

[0094] The advanced separation system and the reverse osmosis system include a lifting water pump, a water storage tank, a pressure pump, a multi-medium filtration system, a dosing device, a booster pump, a nanofiltration device, a backwashing pump, a water tank, an RO feed water pump, a dosing device, a security filter, an RO high-pressure pump, a reverse osmosis device and a water outlet storage tank arranged in sequence.

[0095] The negatively charged nanofiltration membrane system can be made of polyamide (PA), sulfonated polysulfone (SPS), polyvinyl alcohol (PVA), sulfonated polyether sulfone (SPES), cellulose acetate (CA), polysulfone (PS), polyether ether ketone (PEEK) or a composite membrane formed of the above materials; the reverse osmosis membrane material can be cellulose acetate, aromatic polyamide, chitosan membrane, polyphenyl reverse osmosis membrane or a composite membrane made of the above materials.

[0096] The above-mentioned are only embodiments of the present application, and common technical solutions and / or common knowledge of the scheme are not described in detail. It should be pointed out that, for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, and in the present application, unless otherwise specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances. The protection scope claimed in the present application should be subject to the content of its claims, and the specific embodiments and the like in the specification can be used to explain the content of the claims.

Claims

1. A water treatment method for removing total organic carbon from coal chemical biochemical tail water, characterized in that: It comprises the following steps: (1) the coal chemical wastewater after biochemical tail water is divided into difficult degradation coal chemical biochemical tail water and degradable coal chemical biochemical tail water, and the difficult degradation coal chemical biochemical tail water is further treated by the advanced oxidation system; (2) the effluent after the difficult degradation coal chemical biochemical tail water is treated by the advanced oxidation system is mixed with the degradable coal chemical biochemical tail water into the deep biochemical system for treatment, the B / C ratio of the effluent of the advanced oxidation system is greater than 0.3, and the total organic carbon is less than 25 mg / L; (3) the effluent of step (2) is treated by the deep oxidation system; (4) the effluent of step (3) is treated by the deep adsorption system; (5) the effluent of step (4) is treated by the deep separation system, the deep separation system is a negatively charged nanofiltration membrane system, the filtration precision is 150-600 daltons, and the total organic carbon of the effluent of the deep separation system is less than 1 mg / L; (6) the concentrated phase water of step (5) is returned to step (2) and treated by the deep biochemical system; (7) the effluent of step (5) is treated by the reverse osmosis system, the total organic carbon of the effluent of the reverse osmosis system is less than 0.5 mg / L, and the concentrated phase water of the reverse osmosis system is treated by the desalination system.

2. The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The B / C ratio of the degradable coal chemical biochemical tail water is greater than 0.3, and the B / C ratio of the difficult degradation coal chemical biochemical tail water is less than 0.

3. 3.The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The total organic carbon of the degradable coal chemical biochemical tail water is less than 30 mg / L, and the total organic carbon of the difficult degradation coal chemical biochemical tail water is less than 150 mg / L.

4. The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The advanced oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide ozone combined catalytic oxidation system.

5. The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The deep biochemical system is an anoxic-aerobic-biological aerated filter system or an anoxic-aerobic-microfiltration membrane system.

6. The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The deep oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide ozone combined catalytic oxidation system, and the total organic carbon removal rate of the effluent treated by the deep oxidation system is 50%-70%.

7. The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The deep adsorption system is a macroporous adsorption resin system or an activated carbon adsorption system. 8.The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 5, characterized in that: The residence time of the anoxic-aerobic-microfiltration membrane system is 12-48 hours, and the residence time of the anoxic-aerobic-biological aerated filter system is 12-48 hours. 9.The water treatment method for removing total organic carbon from coal chemical biochemical tail water according to claim 1, characterized in that: The negatively charged nanofiltration membrane material is polyamide, sulfonated polysulfone, polyvinyl alcohol, sulfonated polyether sulfone, cellulose acetate, polysulfone, polyether ether ketone or a composite membrane formed by the same.

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