A method for treating reclaimed water

Abstract

The present application relates to the technical field of water treatment, and specifically discloses a method for treating reclaimed water. A method for treating reclaimed water disclosed in the present application specifically includes the following steps in sequence: ozone treatment: water is treated with ozone at a concentration of 2-15 mg / L; photocatalytic treatment: under the condition of titanium dioxide substrate immobilization, xenon gas and ultraviolet light are used in combination to treat water at the same time; activated carbon treatment: activated carbon with an iodine value of 900-1300, activated carbon with an iodine value of 600-900, and activated carbon with an iodine value of 400-600 are used to treat water in sequence until the water quality meets the standard. The present application adopts the above technical solution, combines the advantages of various processes, saves time, energy and water in actual operation, and uses the treated reclaimed water as a circulating cooling water source, which neither causes waste in water supply nor guarantees the basic water quality requirements of circulating cooling water.

Description

Technical Field

[0001] The present application relates to the technical field of water treatment, and in particular to a method for treating reclaimed water. Background Art

[0002] At present, there are a large number of reclaimed water treatment technologies, but after the reclaimed water is treated, its scope of use is greatly restricted due to the limitations of its water quality. Therefore, it is necessary and market demand to appropriately improve the quality of reclaimed water and expand its scope of use.

[0003] The replenishment source for circulating cooling water is typically municipal tap water, which has drinking water quality standards far exceeding those of industrial circulating cooling water. This is wasteful. However, inherent issues with circulating cooling water systems can cause the quality of the circulating cooling water to deteriorate, ultimately leading to a series of problems.

[0004] Therefore, developing an integrated reclaimed water system to treat reclaimed water with lower quality standards than circulating cooling water, allowing the treated water to be used as a circulating cooling water source, would be of great significance. This would avoid waste in water replenishment while ensuring the basic water quality requirements of circulating cooling water. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a method for treating reclaimed water.

[0006] The present application provides a method for treating reclaimed water, which specifically comprises the following steps:

[0007] Ozone treatment: Use ozone with a concentration of 2-15mg / L to treat water. At the same time, use a fully automatic control method to automatically control the ozone concentration of the ozone generator based on the water quality indicators monitored online.

[0008] Photocatalytic treatment: Under the condition of titanium dioxide substrate immobilization, 300-800nm ​​xenon gas, 254nm ultraviolet light, and 185nm ultraviolet light are used to treat water simultaneously;

[0009] Activated carbon treatment: Use activated carbon with iodine value a=900-1300, activated carbon with iodine value b=600-900, and activated carbon with iodine value c=400-600 to treat water in turn until the water quality meets the standards.

[0010] The main process of this application utilizes a combination of O3 ozone treatment, photocatalysis, and activated carbon adsorption. The effluent from each process step undergoes multiple water quality tests based on the characteristics of the reclaimed water. Once it meets the technical requirements, it proceeds to the next step; if it fails, it flows back to the previous step. This maximizes the advantages of each process step, saving time, energy, and water through actual operation to achieve a suitable water quality for cooling circulation. The treated reclaimed water is used as the source of circulating cooling water, eliminating waste in water replenishment while ensuring the basic water quality requirements for circulating cooling water.

[0011] The primary function of ozone treatment is to efficiently oxidize organic matter in water, breaking it down into carbon dioxide, water, and inorganic matter, significantly reducing organic pollutants. Ozone is a strong oxidant that rapidly kills bacteria, viruses, and other microorganisms in water. It also has a certain removal effect on colloids and soil particles in the water, resulting in safer and more thorough disinfection. Furthermore, ozone can oxidize and decompose substances that cause odor and color, improving the sensory properties of the water.

[0012] The main function of photocatalysis is to use light energy to activate catalysts, thereby promoting the decomposition of organic pollutants and converting them into harmless small molecules such as carbon dioxide and water.

[0013] The main function of activated carbon adsorption is to utilize the high specific surface area and porous structure of activated carbon to adsorb pollutants such as dissolved organic matter and heavy metal ions in water; and it can quickly remove odor, color and other impurities in water.

[0014] Preferably, in the ozone treatment, when the water quality indicators are any one or more of CODcr>60mg / L, conductivity>1800us / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2, ozone at a concentration of 8-15mg / L is used to treat the water; when the water quality indicators are any one or more of CODcr=40-60mg / L, conductivity=1500-1800us / cm, total heterotrophic bacteria=50-75 / mL, and fecal coliform count=1-2, ozone at a concentration of 2-7mg / L is used to treat the water.

[0015] Due to the varying quality of the incoming reclaimed water, the unit has clear regulations for the effluent quality. If it does not meet these requirements, it must undergo reflux treatment. To save processing costs and energy, O3 production and concentration must be managed in a step-by-step manner. If the effluent quality data is high, a high concentration is used; if the effluent quality data is low, a low concentration is used. The control method is fully automatic, automatically controlling the ozone generator's gas output based on the online monitored water quality indicators.

[0016] Preferably, when the effluent water quality indicators after ozone treatment meet the following conditions at the same time: CODcr <40 mg / L, conductivity <1500 us / cm, total heterotrophic bacteria <50 / mL, and fecal coliform count = 0, it enters photocatalytic treatment.

[0017] Preferably, in the photocatalytic treatment, the illumination intensity of 300-800 nm xenon gas is 320-380 mW / cm 2 , 254nm ultraviolet light intensity is 240-300mW / cm 2 , 185nm ultraviolet light intensity is 120-220mW / cm 2 .

[0018] Preferably, in the photocatalytic treatment, the wavelength of xenon gas is 400-600 nm and the light intensity is 340-360 mW / cm 2 ; The light intensity of 254nm ultraviolet light is 260-280mW / cm 2 ; The light intensity of 185nm ultraviolet light is 140-200mW / cm 2 .

[0019] In a specific embodiment, the wavelength of the xenon gas can be 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, or 800 nm; the light intensity can be 320 mW / cm 2 、340mW / cm 2 、350mW / cm 2 、360mW / cm 2 、380mW / cm 2 .

[0020] In a specific embodiment, the 254 nm ultraviolet light intensity can be 240 mW / cm 2 , 260mW / cm 2 , 270mW / cm 2 、280mW / cm 2 、300mW / cm 2 .

[0021] In a specific embodiment, the 185 nm ultraviolet light intensity can be 12 mW / cm 2 、140mW / cm 2 、170mW / cm 2 , 200mW / cm 2 , 220mW / cm 2 .

[0022] During the photocatalytic treatment, the light source ratio of the three light sources is adjusted to meet the water quality requirements of the treatment unit; the control method also adopts automatic control, and the luminous power of each of the three light sources is controlled by controlling the light source power supply according to the water quality indicators monitored online.

[0023] Through experimental analysis, it can be seen that in the photocatalytic treatment of this application, the light source ratio of the three light sources is controlled within the above range, which further improves the efficiency of water treatment and reduces the time of water treatment.

[0024] Preferably, when the effluent water quality indicators after the photocatalytic treatment meet the following conditions at the same time: CODcr <30 mg / L, conductivity <1200 us / cm, total iron <0.3 mg / L, and total number of heterotrophic bacteria <10 / mL, it enters the activated carbon treatment.

[0025] Preferably, in the activated carbon treatment, the relationship between the iodine values ​​of the activated carbon is: a=(1.05-2.05)b and b=(1.05-2.05)c.

[0026] Preferably, in the activated carbon treatment, the relationship between the iodine values ​​of the activated carbon is: a=(1.2-1.6)b and b=(1.6-2.0)c.

[0027] In a specific embodiment, the relationship between the iodine values ​​of the activated carbons can be: a=1.2b, a=1.3b, a=1.4b, a=1.5b, a=1.6b; and b=1.6c, b=1.7c, b=1.8c, b=1.9c, b=2.0c.

[0028] Through experimental analysis, it can be seen that in the activated carbon treatment, the relationship between the iodine values ​​of the upper, middle and lower layers of activated carbon in this application is controlled within the above range, which further reflects the inherent advantages of each activated carbon treatment process link, further improves the efficiency of water treatment, and reduces the time of water treatment.

[0029] Preferably, the effluent water quality index after the activated carbon treatment meets the following conditions at the same time: suspended solids <5mg / L, turbidity <10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, free chlorine <0.2mg / L, total heterotrophic bacteria <1×10 5 When the number of fecal coliform bacteria is 0, the water quality meets the standard.

[0030] Water enters the activated carbon treatment tank from the top and exits from the bottom. This primarily ensures that the entire activated carbon layer is fully functional. When activated carbon fails, the entire activated carbon layer fails. Water quality indicators are monitored online. If qualified, it enters the treated water tank for standby use. If unqualified, it is returned to the tank. If unqualified after return, the performance indicators of the three layers of activated carbon are tested. If unqualified, it is replaced.

[0031] Preferably, the reclaimed water is treated using an integrated reclaimed water treatment device;

[0032] The integrated reclaimed water treatment device comprises an ozone generator, a photocatalytic generator, and an activated carbon generator connected in sequence;

[0033] The water outlet ends of the ozone generator, photocatalytic generator, and activated carbon generator are equipped with a reflux device and a water quality detection point, and the water quality detection point is connected to an intelligent multi-parameter water quality detection cabinet;

[0034] The photocatalytic generator is provided with a xenon lamp and an ultraviolet lamp;

[0035] The activated carbon generator is provided with activated carbon with an iodine value of a=900-1300, activated carbon with an iodine value of b=600-900, and activated carbon with an iodine value of c=400-600 from top to bottom. Water flows into the activated carbon generator tank from the upper end and flows out from the lower end.

[0036] In summary, the technical solution of this application has the following effects:

[0037] This application's process combines O3 ozone treatment, photocatalysis, and activated carbon adsorption. The effluent from each process step undergoes multiple water quality tests based on the characteristics of the reclaimed water. Water that meets technical requirements proceeds to the next step, while unqualified water flows back to the previous step. This maximizes the inherent advantages of each process step, saving time, energy, and water through practical operation. The treated reclaimed water is used as a circulating cooling water source, eliminating waste in water replenishment while ensuring the basic water quality requirements for circulating cooling water. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a diagram of the integrated reclaimed water treatment device for this application.

[0039] Figure 2 This is a detailed diagram of the intelligent multi-parameter water quality testing cabinet device in the integrated reclaimed water treatment device of this application. DETAILED DESCRIPTION

[0040] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in this application. Example

[0041] Example 1

[0042] Example 1 provides a method for treating reclaimed water.

[0043] The specific method for treating recycled water in this embodiment is as follows.

[0044] The initial water quality of the treated reclaimed water in this embodiment is as follows: suspended solids = 11.5 mg / L, turbidity = 214 mg / L, Cl - =512mg / L, free chlorine = 0.38mg / L, CODcr = 45.7mg / L, conductivity = 1820us / cm, total iron = 1.05mg / L, NH3-N = 54mg / L, total heterotrophic bacteria = 89 cells / mL, fecal coliform count = 3 cells / L. The designed water treatment capacity is 50 tons / h.

[0045] The diagram of the integrated reclaimed water treatment device is as follows Figure 1 As shown, it includes an ozone generator (O3), a photocatalytic generator, and an activated carbon generator connected in sequence; the outlet ends of the ozone generator, photocatalytic generator, and activated carbon generator are equipped with a reflux device and a water quality detection point, which is connected to the intelligent multi-parameter water quality detection cabinet; the photocatalytic generator is equipped with a xenon lamp and an ultraviolet lamp; the activated carbon generator is equipped with activated carbon with an iodine value of a=1200, activated carbon with an iodine value of b=850, and activated carbon with an iodine value of c=500 from top to bottom, and the water flows into the activated carbon generator tank from the top and flows out from the bottom; a=1.41b and b=1.7c. The details of the intelligent multi-parameter water quality detection cabinet in the integrated water treatment device are shown in the figure below. Figure 2 As shown, when manufacturing the equipment, the unit modules of the ozone generator (O3) and the photocatalytic generator can be used one for use and one for backup.

[0046] Ozone treatment: Use 2-15mg / L ozone concentration to treat water, and adopt full automatic control mode to automatically control the ozone concentration of the ozone generator according to the water quality indicators monitored online; when the water quality indicators are any one or more of CODcr>60mg / L, conductivity>1800us / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2, use 10mg / L ozone concentration to treat water; when the water quality indicators are any one or more of CODcr=40-60mg / L, conductivity=1500-1800us / cm, total heterotrophic bacteria=50-75 / mL, and fecal coliform count=1-2, use 4mg / L ozone concentration to treat water. After 82 seconds of treatment, the effluent water quality indicators after ozone treatment meet the following conditions at the same time: CODcr <40mg / L, conductivity <1500us / cm, total heterotrophic bacteria <50 / mL, fecal coliform count = 0, and enter photocatalytic treatment.

[0047] Photocatalytic treatment: equipped with xenon lamp and ultraviolet lamp, under the condition of titanium dioxide substrate fixation, the combined use of light intensity of 350mW / cm 2 500nm xenon, light intensity is 270mW / cm 2 254nm ultraviolet light with a light intensity of 170mW / cm 2 The water is then treated simultaneously with 185nm ultraviolet light. After 58 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 cells / mL, before entering the activated carbon treatment phase.

[0048] Activated carbon treatment: Water enters the upper end of the activated carbon generator tank and passes through activated carbon with an iodine value of a=1200, activated carbon with an iodine value of b=850, and activated carbon with an iodine value of c=470 (a=1.41b and b=1.81c); the water flows out from the lower end. After 85 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids <5mg / L, turbidity <10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0049] Examples 2-7

[0050] Example 2-7 provides a method for treating reclaimed water.

[0051] The difference between the above embodiment and embodiment 1 is that the photocatalytic treatment steps are different, as shown below.

[0052] In Example 2: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 270 mW / cm 2 500nm xenon, light intensity is 170mW / cm 2 254nm ultraviolet light with a light intensity of 350mW / cm 2 The water is then treated simultaneously with 185nm ultraviolet light. After 112 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 cells / mL, before entering the activated carbon treatment process.

[0053] In Example 3: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 350 mW / cm 2 500nm xenon, light intensity is 170mW / cm 2 254nm ultraviolet light with a light intensity of 270mW / cm 2 The water is then treated simultaneously with 185nm ultraviolet light. After 138 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 / mL, before entering the activated carbon treatment phase.

[0054] In Example 4: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 320 mW / cm 2 500nm xenon, light intensity is 270mW / cm 2 254nm ultraviolet light with a light intensity of 170mW / cm 2 The water is then treated simultaneously with 185nm ultraviolet light. After 65 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 / mL, before entering the activated carbon treatment phase.

[0055] In Example 5, photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 380 mW / cm 2 500nm xenon, light intensity is 270mW / cm 2 254nm ultraviolet light with a light intensity of 170mW / cm 2 The water is then treated simultaneously with 185nm ultraviolet light. After 70 seconds of ozone treatment, if the effluent meets the following conditions: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 / mL, it enters the activated carbon treatment process.

[0056] In Example 6: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 350 mW / cm 2 500nm xenon, light intensity is 240mW / cm 2 254nm ultraviolet light with a light intensity of 220mW / cm 2The water is then treated simultaneously with 185nm ultraviolet light. After 64 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 / mL, before entering the activated carbon treatment phase.

[0057] In Example 7, photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 350 mW / cm 2 500nm xenon, light intensity of 300mW / cm 2 254nm ultraviolet light with a light intensity of 120mW / cm 2 The water was simultaneously treated with 185nm ultraviolet light. After 59 seconds of treatment, the effluent quality indicators after ozone treatment met the following conditions: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, and total heterotrophic bacteria <10 / mL, and then entered the activated carbon treatment.

[0058] The other process parameters in the above embodiment are the same as those in Example 1.

[0059] Examples 8-11

[0060] Examples 8-11 provide a method for treating reclaimed water.

[0061] The difference between the above embodiment and embodiment 1 is that the activated carbon treatment steps are different, as shown below.

[0062] In Example 8: Activated carbon treatment: Water enters the upper end of the activated carbon generator tank and passes through activated carbon with an iodine value of a = 1300, activated carbon with an iodine value of b = 650, and activated carbon with an iodine value of c = 600 (a = 2b and b = 1.08c); the water flows out from the lower end. After 158 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids < 5mg / L, turbidity < 10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0063] In Example 9: Activated carbon treatment: Water enters the upper end of the activated carbon generator tank and passes through activated carbon with an iodine value of a = 1000, activated carbon with an iodine value of b = 900, and activated carbon with an iodine value of c = 400 (a = 1.1b and b = 2.25c); the water flows out from the lower end. After 141 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids < 5mg / L, turbidity < 10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0064] In Example 10: Activated carbon treatment: Water enters the upper end of the activated carbon generator tank and passes through activated carbon with an iodine value of a = 1020, activated carbon with an iodine value of b = 840, and activated carbon with an iodine value of c = 420 (a = 1.21b and b = 2c); the water flows out from the lower end. After 90 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids < 5mg / L, turbidity < 10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0065] In Example 11: Activated carbon treatment: Water enters the upper end of the activated carbon generator tank and passes through activated carbon with an iodine value of a = 1200, activated carbon with an iodine value of b = 750, and activated carbon with an iodine value of c = 460 (a = 1.6b and b = 1.63c); the water flows out from the lower end. After 89 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids < 5mg / L, turbidity < 10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0066] The other process parameters in the above embodiment are the same as those in Example 1.

[0067] Comparative Example

[0068] Comparative Example 1-2

[0069] Comparative Examples 1-2 each provide a method for treating reclaimed water.

[0070] The difference between the comparative example and Example 1 is that the photocatalytic treatment steps are different, as shown below.

[0071] Comparative Example 1: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 350 mW / cm 2 500nm xenon, light intensity is 270mW / cm 2 The water is then treated simultaneously with 254nm ultraviolet light. After 268 seconds of ozone treatment, the effluent meets the following quality criteria: CODcr < 30mg / L, conductivity < 1200us / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 / mL, before entering the activated carbon treatment phase.

[0072] Comparative Example 2: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp were provided, and the combined use of light intensity was 350 mW / cm 2 500nm xenon, light intensity is 270mW / cm 2 254nm ultraviolet light with a light intensity of 170mW / cm 2 The water was then treated simultaneously with 280nm ultraviolet light. After 209 seconds of ozone treatment, the effluent met the following quality criteria: CODcr < 30mg / L, conductivity < 1200µs / cm, total iron < 0.3mg / L, and total heterotrophic bacteria < 10 cells / mL, before entering the activated carbon treatment.

[0073] The other process parameters in the above comparative example are the same as those in Example 1.

[0074] Comparative Examples 3-4

[0075] Comparative Examples 3-4 respectively provide a method for treating reclaimed water.

[0076] The difference between the comparative example and Example 1 is that the activated carbon treatment steps are different, as shown below.

[0077] In comparative example 3: activated carbon treatment: water flows into the upper end of the activated carbon generator tank, passes through activated carbon with an iodine value of a = 750, activated carbon with an iodine value of b = 500, and activated carbon with an iodine value of c = 300 (a = 1.5b and b = 1.67c); the water flows out from the lower end. After 304 seconds of treatment, the effluent water quality indicators meet the following conditions: suspended solids < 5mg / L, turbidity < 10mg / L, Cl -<100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0078] In comparative example 4: activated carbon treatment: water flows into the upper end of the activated carbon generator tank, passes through activated carbon with an iodine value of a=1400, and activated carbon with an iodine value of b=850 (a=1.41b); the water flows out from the lower end. After 288s of treatment, the effluent water quality indicators meet the following conditions: suspended solids <5mg / L, turbidity <10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0079] The other process parameters in the above comparative example are the same as those in Example 1.

[0080] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for treating reclaimed water, characterized in that: Specifically, the following steps are performed in sequence: Ozone treatment: 2-15mg / L ozone is used to treat water. At the same time, a fully automatic control method is adopted to automatically control the ozone concentration of the ozone generator according to the water quality indicators monitored online. During the ozone treatment, if the water quality indicators are any one or more of CODcr>60mg / L, conductivity>1800μs / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2, 8-15mg / L ozone is used to treat the water. The water quality indicators are CODcr>60mg / L, conductivity>1800μs / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2. When the water quality index of the ozone treatment meets the following conditions simultaneously: CODcr < 40 mg / L, conductivity < 1500 μs / cm, total heterotrophic bacteria < 50 cells / mL, and fecal coliform bacteria = 0, the water enters the photocatalytic treatment; Photocatalytic treatment: Under the condition of titanium dioxide substrate immobilization, 300-800nm ​​xenon gas, 254nm ultraviolet light and 185nm ultraviolet light are used to treat water simultaneously. When the water quality indicators after photocatalytic treatment meet the following conditions: CODcr <30mg / L, conductivity <1200μs / cm, total iron <0.3mg / L, and total heterotrophic bacteria <10 / mL, the water enters the activated carbon treatment; Activated carbon treatment: Use activated carbon with iodine value a=900-1300, activated carbon with iodine value b=600-900 and activated carbon with iodine value c=400-600 to treat water in turn until the water quality meets the standards.

2. The method for treating reclaimed water according to claim 1, wherein: In the photocatalytic treatment, the illumination intensity of 300-800nm ​​xenon gas is 320-380mW / cm 2 , 254nm ultraviolet light intensity is 240-300mW / cm 2 , 185nm ultraviolet light intensity is 120-220mW / cm 2 .

3. The method for treating reclaimed water according to claim 2, wherein: In the photocatalytic treatment, the wavelength of xenon gas is 400-600nm and the light intensity is 340-360mW / cm 2 ; The light intensity of 254nm ultraviolet light is 260-280mW / cm 2 ; The light intensity of 185nm ultraviolet light is 140-200mW / cm 2 .

4. The method for treating reclaimed water according to claim 1, wherein: In the activated carbon treatment, the relationship between the iodine values ​​of the activated carbon is: a=(1.05-2.05)b and b=(1.05-2.05)c.

5. The method for treating reclaimed water according to claim 4, characterized in that: In the activated carbon treatment, the relationship between the iodine values ​​of the activated carbon is: a=(1.2-1.6)b and b=(1.6-2.0)c.

6. The method for treating reclaimed water according to claim 1, wherein: The effluent water quality indicators after activated carbon treatment meet the following conditions at the same time: suspended solids <5mg / L, turbidity <10mg / L, Cl - <100mg / L, free chlorine <0.2mg / L, CODcr <30mg / L, conductivity <600μs / cm, total iron <0.3mg / L, NH3-N <5mg / L, total heterotrophic bacteria <1×10 5 When the number of fecal coliform bacteria is 0, the water quality meets the standard.

7. The method for treating reclaimed water according to claim 1, characterized in that: Treat the reclaimed water using an integrated reclaimed water treatment device; The integrated reclaimed water treatment device comprises an ozone generator, a photocatalytic generator, and an activated carbon generator connected in sequence; The water outlet ends of the ozone generator, photocatalytic generator, and activated carbon generator are equipped with a reflux device and a water quality detection point, and the water quality detection point is connected to an intelligent multi-parameter water quality detection cabinet; The photocatalytic generator is provided with a xenon lamp and an ultraviolet lamp; The activated carbon generator is provided with activated carbon with an iodine value of a=900-1300, activated carbon with an iodine value of b=600-900, and activated carbon with an iodine value of c=400-600 from top to bottom. Water flows into the activated carbon generator tank from the upper end and flows out from the lower end.

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