Reclaimed water treatment method

Abstract

The invention relates to the technical field of water treatment, and particularly discloses a reclaimed water treatment method. The invention discloses a reclaimed water treatment method. The reclaimed water treatment method specifically comprises the following steps in sequence: ozone treatment: treating water by adopting ozone with the concentration of 2-15mg / L; photocatalytic treatment: under the condition of immobilization of the titanium dioxide base material, xenon and ultraviolet rays are jointly utilized, and water is treated at the same time; activated carbon treatment: sequentially utilizing activated carbon with the activated carbon iodine value of 900-1300, activated carbon with the activated carbon iodine value of 600-900 and activated carbon with the activated carbon iodine value of 400-600 to treat the water until the water quality reaches the standard. According to the technical scheme, the advantages of various technologies are combined, time, energy and water are saved in actual operation, the treated reclaimed water serves as a circulating cooling water source, waste is not caused in water source supply, and the basic water quality requirement of circulating cooling water can be met.

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 in line with market demand to appropriately improve the quality of reclaimed water and expand its scope of use.

[0003] The replenishment water source for circulating cooling water is usually municipal tap water, whose water quality standard is drinking water, which is much higher than the water quality standard of industrial circulating cooling water. This is a waste. However, due to the inevitable problems in the circulation of cooling water system, the quality of circulating cooling water will continue to deteriorate, eventually causing a series of problems.

[0004] Therefore, it is of great significance to develop an integrated reclaimed water device to treat reclaimed water with a water quality standard lower than that of circulating cooling water, so that the treated reclaimed water can be used as a circulating cooling water source, which will not only avoid waste in water supply, but also ensure the basic water quality requirements of circulating cooling water. Summary of the invention In order to solve the above technical problems, the present application provides a method for treating reclaimed water.

[0005] The present application provides a method for treating reclaimed water, which specifically comprises the following steps in sequence: Ozone treatment: Use 2-15mg / L ozone to treat water, and use full-automatic control to automatically control the ozone concentration of the ozone generator according to the water quality indicators monitored online; Photocatalytic treatment: Under the condition of titanium dioxide substrate fixation, 300-800nm ​​xenon gas, 254nm ultraviolet light, and 185nm ultraviolet light are used to treat water simultaneously; 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 the water in turn until the water quality meets the standard.

[0006] The main process of this application adopts O 3The three processes of ozone treatment, photocatalysis and activated carbon adsorption are combined. The effluent of each process link is tested for water quality according to the characteristics of the reclaimed water quality. If it meets the technical requirements, it will enter the next link. If it fails, it will flow back to the previous link. The advantages of each process link are reflected to the maximum extent. Through actual operation, time, energy and water are saved to achieve the water quality suitable for cooling circulating water. The treated reclaimed water is used as the source of circulating cooling water, which neither causes waste in water supply nor guarantees the basic water quality requirements of circulating cooling water.

[0007] The main function of ozone treatment is to efficiently oxidize organic matter in water and decompose it into carbon dioxide, water and inorganic matter, thereby significantly reducing organic pollutants in water. Ozone is a strong oxidant that can quickly kill bacteria, viruses and other microorganisms in water; it also has a certain cleaning effect on colloids, soil particles, etc. in water, and the disinfection effect is safer and more thorough. At the same time, ozone can oxidize and decompose substances that produce odor and color, improving the sensory indicators of water.

[0008] 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.

[0009] 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 soluble organic matter and heavy metal ions in water; and it can quickly remove odor, color and other impurities in water.

[0010] Preferably, in the ozone treatment, when the water quality index is any one or more of CODcr>60mg / L, conductivity>1800us / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2, 8-15mg / L of ozone is used to treat the water; when the water quality index is 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, 2-7mg / L of ozone is used to treat the water.

[0011] Due to the different and changing water quality of the reclaimed water, there are clear regulations on the effluent quality of the unit. If it does not meet the requirements, it needs to be refluxed. In order to save treatment costs and energy, O 3 The output and concentration are managed in a step-by-step manner. When the water quality data of the effluent is detected to be high, a high concentration is used, and when the water quality data of the effluent is detected to be low, a low concentration is used. The control method adopts a fully automatic control method, which automatically controls the gas output of the ozone generator according to the water quality indicators monitored online.

[0012] Preferably, when 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, and fecal coliform count=0, it enters photocatalytic treatment.

[0013] Preferably, 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 .

[0014] Preferably, 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 .

[0015] In a specific embodiment, the wavelength of the xenon gas can be 300nm, 400nm, 500nm, 600nm, 700nm, 800nm; the light intensity can be 320mW / cm 2 、340mW / cm 2 、350mW / cm 2 、360mW / cm 2 、380mW / cm 2 .

[0016] In a specific embodiment, the light intensity of 254nm ultraviolet light can be 240mW / cm 2 、260mW / cm 2 、270mW / cm 2 、280mW / cm 2 、300mW / cm 2 .

[0017] In a specific embodiment, the light intensity of 185nm ultraviolet light can be 12mW / cm 2 、140mW / cm 2 、170mW / cm 2 , 200mW / cm 2 、220mW / cm 2 .

[0018] The light source ratio of the three light sources is adjusted during photocatalytic treatment 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.

[0019] Through experimental analysis, it can be known that in the photocatalytic treatment of the present 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.

[0020] 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, total heterotrophic bacteria <10 / mL, it enters the activated carbon treatment.

[0021] 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.

[0022] 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.

[0023] In a specific embodiment, the relationship between the iodine values ​​of activated carbon 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.

[0024] Through experimental analysis, it can be known that in the activated carbon treatment, the relationship between the iodine values ​​of the upper, middle and lower layers of activated carbon 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.

[0025] Preferably, the effluent water quality indicators after the 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, free chlorine<0.2mg / L, total number of heterotrophic bacteria<1×10 5 When the number of fecal coliform bacteria is 0, the water quality meets the standard.

[0026] The water flows in from the upper end of the activated carbon treatment tank and flows out from the lower end. The main effect is to make the entire activated carbon fully exert its effectiveness. When the activated carbon fails, it is the whole state. Through the online monitoring of water quality indicators, qualified water enters the treated water tank for standby. If there are unqualified items, it will be refluxed. If it is still unqualified after reflux, the performance indicators of the three-layer activated carbon will be tested. If it fails, it will be replaced.

[0027] Preferably, the reclaimed water is treated 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 which are connected in sequence; The water outlet ends of the ozone generator, photocatalytic generator and activated carbon generator are provided 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, and water flows into the activated carbon generator tank from the upper end and flows out from the lower end.

[0028] In summary, the technical solution of this application has the following effects: This application process adopts O 3 The three processes of ozone treatment, photocatalysis and activated carbon adsorption are combined. The effluent of each process link is tested for water quality according to the characteristics of the reclaimed water quality. If it meets the technical requirements, it will enter the next link. If it fails, it will flow back to the previous link. The advantages of each process link are reflected to the maximum extent. Through actual operation, time, energy and water are saved. The treated reclaimed water is used as the source of circulating cooling water, which not only avoids waste in water supply, but also guarantees the basic water quality requirements of circulating cooling water. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a diagram of the integrated reclaimed water treatment device of this application.

[0030] 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

[0031] 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 the present application. Example

[0032] Example 1 Example 1 provides a method for treating reclaimed water.

[0033] The specific method for treating the reclaimed water in this embodiment is as follows.

[0034] 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, NH 3 -N=54mg / L, total heterotrophic bacteria=89 / mL, fecal coliform count=3 / L. The designed water treatment capacity is 50 tons / h.

[0035] The picture of the integrated 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 water outlets of the ozone generator, photocatalytic generator, and activated carbon generator are provided 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; a xenon lamp and an ultraviolet lamp are provided in the photocatalytic generator; the activated carbon generator is provided 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 in from the upper end of the activated carbon generator tank and out from the lower end; a=1.41b and b=1.7c. The detailed diagram of the intelligent multi-parameter water quality detection cabinet in the integrated reclaimed water treatment device is shown in FIG. 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.

[0036] Ozone treatment: Use 2-15mg / L ozone to treat the water, and use full-automatic control 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 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, use 4mg / L ozone to treat the water. After 82 seconds of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <40 mg / L, conductivity <1500 us / cm, total heterotrophic bacteria <50 / mL, fecal coliform count = 0, and entered the photocatalytic treatment.

[0037] 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, light intensity is 170mW / cm 2 The water was treated with 185nm ultraviolet light at the same time. After 58s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0038] Activated carbon treatment: water flows into 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); water flows out from the lower end. After 85s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0039] Embodiment 2-7 Example 2-7 provides a method for treating grey water.

[0040] The differences between the above embodiment and embodiment 1 are as follows: the photocatalytic treatment steps are different.

[0041] In Example 2: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp are provided, and the combined use of light intensity is 270 mW / cm 2 500nm xenon, light intensity is 170mW / cm 2 254nm ultraviolet light, light intensity is 350mW / cm 2 The water was treated with 185nm ultraviolet light at the same time. After 112s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0042] In Example 3: Photocatalytic treatment: a xenon lamp and an ultraviolet lamp are provided, and the combined use of light intensity is 350 mW / cm 2 500nm xenon, light intensity is 170mW / cm 2 254nm ultraviolet light, light intensity is 270mW / cm 2 The water was treated with 185nm ultraviolet light at the same time. After 138s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0043] 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, light intensity is 170mW / cm 2 The water is treated with 185nm ultraviolet light at the same time. After 65s of treatment, the effluent water quality indicators after ozone treatment meet the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and enter the activated carbon treatment.

[0044] 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, light intensity is 170mW / cm 2 The water is treated with 185nm ultraviolet light at the same time. After 70s of treatment, the effluent water quality indicators after ozone treatment meet the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and enter the activated carbon treatment.

[0045] 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, light intensity is 220mW / cm 2The water is treated with 185nm ultraviolet light at the same time. After 64s of treatment, the effluent water quality indicators after ozone treatment meet the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and enter the activated carbon treatment.

[0046] 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 is 300mW / cm 2 254nm ultraviolet light, light intensity is 120mW / cm 2 The water was treated with 185nm ultraviolet light at the same time. After 59s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0047] The other process parameters in the above embodiment are the same as those in embodiment 1.

[0048] Embodiment 8-11 Examples 8-11 provide a method for treating grey water.

[0049] The difference between the above embodiment and embodiment 1 is that the activated carbon treatment steps are different, as shown below.

[0050] In Example 8: Activated carbon treatment: water flows into 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); water flows out from the lower end. After 158s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0051] In Example 9: Activated carbon treatment: water flows into 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); water flows out from the lower end. After 141s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0052] In Example 10: Activated carbon treatment: water flows into 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); water flows out from the lower end. After 90s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0053] In Example 11: Activated carbon treatment: water flows into 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); water flows out from the lower end. After 89 seconds of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0054] The other process parameters in the above embodiment are the same as those in embodiment 1.

[0055] Comparative Example Comparative Example 1-2 Comparative Examples 1-2 respectively provide a method for treating reclaimed water.

[0056] The difference between the comparative example and Example 1 is that the photocatalytic treatment steps are different, as shown below.

[0057] In 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 was treated with 254nm ultraviolet light at the same time. After 268s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0058] In 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, light intensity is 170mW / cm 2 The water was treated with 280nm ultraviolet light at the same time. After 209s of treatment, the effluent water quality indicators after ozone treatment met the following conditions at the same time: CODcr <30mg / L, conductivity <1200us / cm, total iron <0.3mg / L, total heterotrophic bacteria <10 / mL, and entered the activated carbon treatment.

[0059] The other process parameters in the above comparative example are the same as those in Example 1.

[0060] Comparative Examples 3-4 Comparative Examples 3-4 each provide a method for treating reclaimed water.

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

[0062] In comparative example 3: activated carbon treatment: water flows into the upper end of the activated carbon generator tank, and 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); water flows out from the lower end. After 304s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0063] 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); water flows out from the lower end. After 288s of treatment, the effluent water quality indicators 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 <600us / cm, total iron <0.3mg / L, NH 3 -N<5mg / L, total number of heterotrophic bacteria<1×10 5 / mL, fecal coliform count = 0, the water quality meets the standard.

[0064] The other process parameters in the above comparative example are the same as those in Example 1.

[0065] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for treating reclaimed water, characterized in that: Specifically, the following steps are performed in sequence: Ozone treatment: Use 2-15mg / L ozone to treat water, and use full-automatic control to automatically control the ozone concentration of the ozone generator according to the water quality indicators monitored online; Photocatalytic treatment: Under the condition of titanium dioxide substrate fixation, 300-800nm ​​xenon gas, 254nm ultraviolet light, and 185nm ultraviolet light are used to treat water simultaneously; 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 the water in turn until the water quality meets the standard.

2. The method for treating reclaimed water according to claim 1, characterized in that: In the ozone treatment, when the water quality index is any one or more of CODcr>60mg / L, conductivity>1800us / cm, total heterotrophic bacteria>75 / mL, and fecal coliform count>2, ozone with a concentration of 8-15mg / L is used to treat the water; when the water quality index is 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 with a concentration of 2-7mg / L is used to treat the water.

3. The method for treating reclaimed water according to claim 1, characterized in that: When the effluent water quality indicators after the ozone treatment meet the following conditions at the same time: CODcr<40mg / L, conductivity<1500us / cm, total heterotrophic bacteria<50 / mL, and fecal coliform count=0, it enters the photocatalytic treatment.

4. The method for treating reclaimed water according to claim 1, characterized in that: 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 .

5. The method for treating reclaimed water according to claim 4, characterized in that: 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 .

6. The method for treating reclaimed water according to claim 1, characterized in that: When the effluent water quality indicators after the photocatalytic treatment meet the following conditions at the same time: CODcr<30mg / L, conductivity<1200us / cm, total iron<0.3mg / L, total heterotrophic bacteria<10 / mL, it enters the activated carbon treatment.

7. The method for treating reclaimed water according to claim 1, characterized in that: 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.

8. The method for treating reclaimed water according to claim 7, 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.

9. The method for treating reclaimed water according to claim 1, characterized in that: 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 <600us / cm, total iron <0.3mg / L, NH3-N <5mg / L, free chlorine <0.2mg / L, total number of heterotrophic bacteria <1×10 5 When the number of fecal coliform bacteria is 0, the water quality meets the standard.

10. 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 which are connected in sequence; The water outlet ends of the ozone generator, photocatalytic generator and activated carbon generator are provided 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, and water flows into the activated carbon generator tank from the upper end and flows out from the lower end.

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