Treatment method of aircraft deicing wastewater

Abstract

The invention provides a treatment method of aircraft deicing wastewater, and belongs to the technical field of wastewater treatment. The treatment method provided by the invention comprises the following steps: (1) carrying out low-temperature evaporation and concentration on the aircraft deicing wastewater, and condensing to obtain distilled water; the temperature of the low-temperature evaporation concentration is 35-50 DEG C; and (2) carrying out deep treatment on the distilled water obtained in the step (1) to obtain purified water. The aircraft deicing wastewater is subjected to low-temperature evaporation and concentration, compared with traditional high-temperature evaporation, the energy consumption is greatly reduced, the operation cost is reduced, and the distilled water subjected to low-temperature evaporation and concentration is subjected to deep treatment, so that the effluent reaches the discharge or reuse standard.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a method for treating aircraft deicing wastewater. Background Art

[0002] In the aviation field, a large amount of wastewater is generated during aircraft deicing operations. This wastewater contains various pollutants such as deicing agents, impurities, and microorganisms. If directly discharged, it will cause serious pollution to the environment. The evaporation and concentration method is a simple and efficient treatment method. Usually, the wastewater to be treated is heated to boiling (about 100 °C) to evaporate the water in the wastewater. However, its energy consumption is relatively high, which limits its practical application. Therefore, how to reduce the energy consumption in the process of treating aircraft deicing wastewater has become a difficult problem in the existing technology. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for treating aircraft deicing wastewater. The treatment method provided by the present invention has relatively low energy consumption.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a method for treating aircraft deicing wastewater, comprising the following steps:

[0006] (1) Low-temperature evaporating and concentrating the aircraft deicing wastewater and then condensing it to obtain distilled water; the temperature of the low-temperature evaporation and concentration is 35-50 °C;

[0007] (2) Deeply treating the distilled water obtained in step (1) to obtain purified water.

[0008] Preferably, the pressure of the low-temperature evaporation and concentration in step (1) is -100 to -98 kPa.

[0009] Preferably, the temperature of the low-temperature evaporation and concentration in step (1) is 35-45 °C.

[0010] Preferably, the deep treatment in step (2) includes one or more of activated carbon adsorption, reverse osmosis, and ozone oxidation.

[0011] Preferably, the particle size of the activated carbon is 20-50 mesh, the pore diameter of the activated carbon is 0.7-1.2 nm, the porosity of the activated carbon is 0.5-0.7 cm 3 / g, and the specific surface area of the activated carbon > 1200 m 2 / g.

[0012] Preferably, the pressure of the reverse osmosis is 15-30 bar, the flux of the reverse osmosis is 20-50 L / m 2 ·h, and the temperature of the reverse osmosis is 15-35 °C.

[0013] Preferably, the pH value of the ozone oxidation is >9, the time of the ozone oxidation is 1 to 3 h, and the temperature of the ozone oxidation is 25 to 35 °C.

[0014] Preferably, hydrogen peroxide is added during the ozone oxidation.

[0015] Preferably, the mass concentration of the hydrogen peroxide is 30%.

[0016] Preferably, the volume ratio of the hydrogen peroxide to the distilled water is 1:(200 - 500).

[0017] The present invention provides a method for treating aircraft deicing wastewater, comprising the following steps: (1) subjecting the aircraft deicing wastewater to low-temperature evaporation and concentration and then condensing to obtain distilled water; the temperature of the low-temperature evaporation and concentration is 35 to 50 °C; (2) subjecting the distilled water obtained in step (1) to advanced treatment to obtain purified water. The present invention performs low-temperature evaporation and concentration on the aircraft deicing wastewater, which greatly reduces the energy consumption and operation cost compared with the traditional high-temperature evaporation. The advanced treatment of the distilled water after low-temperature evaporation and concentration enables the effluent to meet the discharge or reuse standards. The results of the examples show that the energy consumption of the treatment method of the present invention is about 1 kWh / kg of ethylene glycol, while the energy consumption of the traditional high-temperature evaporation is about 4.2 kWh / kg of ethylene glycol. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the device used for the method for treating aircraft deicing wastewater according to the present invention;

[0019] Figure 2 is a macroscopic view of the device used in the low-temperature evaporation and concentration process in the method for treating aircraft deicing wastewater according to the present invention;

[0020] Figure 3 is a curve of the change in the ethylene glycol content in the concentrated liquid at different times in step (1) of Example 2;

[0021] Figure 4 is the ethylene glycol concentration rate in the concentrated liquid at different times in step (1) of Example 2;

[0022] Figure 5 is a curve of the change in the ethylene glycol content in the distilled water at different times in step (1) of Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention provides a method for treating aircraft deicing wastewater, comprising the following steps:

[0024] (1) Subjecting the aircraft deicing wastewater to low-temperature evaporation and concentration and then condensing to obtain distilled water; the temperature of the low-temperature evaporation and concentration is 35 to 50 °C;

[0025] (2) Deeply treat the distilled water obtained in the step (1) to obtain purified water.

[0026] The present invention condenses the aircraft deicing wastewater after low-temperature evaporation and concentration to obtain distilled water.

[0027] The present invention has no special limitation on the source of the aircraft deicing wastewater, and the aircraft deicing wastewater well-known to those skilled in the art can be used.

[0028] In the present invention, the aircraft deicing wastewater includes alcohols (propylene glycol and / or ethylene glycol), water, surfactants, corrosion inhibitors, thickeners, aircraft fuel, sand and other garbage.

[0029] In the present invention, the aircraft deicing wastewater is preferably pretreated before low-temperature evaporation and concentration.

[0030] In the present invention, the pretreatment preferably includes oil removal and filtration carried out in sequence.

[0031] The present invention preferably removes oil from the aircraft deicing wastewater through an oil skimmer. The present invention has no special limitation on the operation of removing oil through the oil skimmer, and the technical solutions well-known to those skilled in the art can be used. The present invention has no special limitation on the source of the oil skimmer, and commercially available products well-known to those skilled in the art can be used.

[0032] The present invention preferably filters the oil-removed aircraft deicing wastewater through a quartz sand filter tank. In the present invention, the diameter of the quartz sand is preferably 0.5 - 1 mm, and the thickness of the filter layer composed of the quartz sand is preferably 0.9 - 1.5 m. The present invention removes suspended solids and part of the colloid in the aircraft deicing wastewater through filtration. By controlling the particle size of the quartz sand and the thickness of the filter layer within the above ranges, the present invention can more fully remove the suspended solids and colloids in the aircraft deicing wastewater.

[0033] The present invention pretreats the aircraft deicing wastewater, which is more conducive to the subsequent low-temperature evaporation and concentration.

[0034] In the present invention, the pressure of the low-temperature evaporation and concentration is preferably -100 to -98 kPa; the temperature of the low-temperature evaporation and concentration is 35 to 50 °C. As an implementation manner, the temperature of the low-temperature evaporation and concentration can specifically be 35 °C, 37 °C, 40 °C, 42 °C, 45 °C, 48 °C or 50 °C.

[0035] The present invention has no special limitation on the time of the low-temperature evaporation and concentration, and it can be adjusted according to the inlet concentration and treatment requirements of the aircraft deicing wastewater, as well as the treatment water volume.

[0036] In the present invention, when the amount of aircraft de-icing wastewater is large, continuous treatment is preferably carried out. In the present invention, during the continuous treatment, the water inflow of the aircraft de-icing wastewater is preferably adjusted by a liquid level gauge in the evaporation tank of the low-temperature evaporation and concentration equipment. When it is lower than the bottom liquid level in the evaporation tank (near the upper part of the heating coil), the equipment automatically fills with water. When it is higher than the top liquid level in the evaporation tank, the equipment stops filling with water.

[0037] The present invention controls the pressure and temperature of the low-temperature evaporation and concentration within the above ranges, enabling the wastewater to be evaporated and concentrated at a relatively low temperature, reducing energy consumption, and at the same time avoiding damage to the structure of the alcohol substances in the aircraft de-icing wastewater, which is beneficial to improving the effluent quality and the recycling and reuse of alcohol substances.

[0038] In the present invention, an antifoaming agent is preferably added during the low-temperature evaporation and concentration process. In the present invention, the antifoaming agent is preferably a non-ionic surfactant. The present invention has no special limitation on the addition amount of the antifoaming agent, and it can be selected according to the amount of foam during the low-temperature evaporation and concentration process. Adding the antifoaming agent in the present invention can reduce the amount of foam during the low-temperature evaporation and concentration process, which is more conducive to the progress of the low-temperature evaporation and concentration process and improving the effluent quality.

[0039] The present invention has no special limitation on the operation of the condensation, as long as the steam of the low-temperature evaporation and concentration can be fully condensed to obtain distilled water.

[0040] In the present invention, during the low-temperature evaporation and concentration process, other substances are concentrated to obtain a concentrated solution.

[0041] In the present invention, the concentrated solution is preferably post-treated to recover the alcohol substances therein as raw materials for automotive antifreeze, cold storage condensers, or carbon sources for sewage treatment plants.

[0042] The present invention has no special limitation on the operation of the post-treatment. The alcohol substances can be recovered by using the post-treatment technical solutions well-known to those skilled in the art. Post-treating the concentrated solution in the present invention enables the recycling and reuse of resources.

[0043] After obtaining the distilled water, the present invention further processes the distilled water to obtain purified water.

[0044] In the present invention, the further treatment preferably includes one or more of activated carbon adsorption, reverse osmosis, and ozone oxidation.

[0045] The present invention preferably fills activated carbon into a columnar filter, and then passes the distilled water through the columnar filter for activated carbon adsorption.

[0046] In the present invention, the particle size of the activated carbon is preferably 20 - 50 mesh; the pore diameter of the activated carbon is preferably 0.7 - 1.2 nm; the porosity of the activated carbon is preferably 0.5 - 0.7 cm3 / g; the specific surface area of the activated carbon is preferably > 1200 m 2 / g.

[0047] In the present invention, the activated carbon is preferably coconut shell activated carbon. The present invention does not have special limitations on the source of the activated carbon, and commercially available products well-known to those skilled in the art can be used, as long as its various parameters are within the above ranges.

[0048] In the present invention, the thickness of the activated carbon layer is preferably 1 - 2.5 m.

[0049] In the present invention, the flow rate of distilled water during the adsorption by the activated carbon is preferably 0.1 - 0.6 m / h. As an implementation manner, the flow rate of distilled water during the adsorption by the activated carbon can specifically be 0.1 m / h, 0.2 m / h, 0.3 m / h, 0.4 m / h, 0.5 m / h or 0.6 m / h. By controlling the various parameters of the activated carbon adsorption within the above ranges in the present invention, impurities in the distilled water can be removed more fully, and the water quality of the effluent can be further improved.

[0050] In the present invention, the pressure of the reverse osmosis is preferably 15 - 30 bar. As an implementation manner, the pressure of the reverse osmosis can specifically be 15 bar, 20 bar, 25 bar or 30 bar.

[0051] In the present invention, the flux of the reverse osmosis is preferably 20 - 50 L / m 2 ·h. As an implementation manner, the flux of the reverse osmosis can specifically be 20 L / m 2 ·h, 25 L / m 2 ·h, 30 L / m 2 ·h, 35 L / m 2 ·h, 40 L / m 2 ·h, 45 L / m 2 ·h or 50 L / m 2 ·h.

[0052] In the present invention, the temperature of the reverse osmosis is preferably 15 - 35 °C. As an implementation manner, the temperature of the reverse osmosis can specifically be 15 °C, 20 °C, 25 °C, 30 °C or 35 °C.

[0053] In the present invention, the pH value of the reverse osmosis is preferably 6.5 - 7.5.

[0054] In the present invention, the material of the reverse osmosis membrane is preferably polyamide; the pore diameter of the reverse osmosis membrane is preferably 0.4 - 0.6 nm, more preferably 0.5 nm; the thickness of the reverse osmosis membrane is preferably 140 - 160 μm, more preferably 150 μm. By controlling the parameters of reverse osmosis within the above ranges in the present invention, impurities in distilled water can be removed more thoroughly, further improving the water quality of the effluent.

[0055] In the present invention, the mass ratio of ozone to organic pollutants (COD) in distilled water is preferably (1 - 5):1. As an embodiment, the mass ratio of ozone to organic pollutants (COD) in distilled water can specifically be 1:1, 2:1, 3:1, 4:1, or 5:1.

[0056] In the present invention, the pH value of ozone oxidation is preferably > 9.

[0057] In the present invention, the time of ozone oxidation is preferably 1 - 3 h. As an embodiment, the time of ozone oxidation can specifically be 1 h, 1.5 h, 2 h, 2.5 h, or 3 h.

[0058] In the present invention, the temperature of ozone oxidation is preferably 25 - 35 °C. As an embodiment, the temperature of ozone oxidation can specifically be 25 °C, 28 °C, 30 °C, 32 °C, or 35 °C.

[0059] In the present invention, hydrogen peroxide is preferably added during ozone oxidation.

[0060] In the present invention, the mass concentration of hydrogen peroxide is preferably 30%; the volume ratio of hydrogen peroxide to distilled water is preferably 1:(200 - 500). As an embodiment, the volume ratio of hydrogen peroxide to distilled water can specifically be 1:200, 1:300, 1:400, or 1:500.

[0061] By controlling the parameters of ozone oxidation within the above ranges in the present invention, impurities in distilled water can be removed more thoroughly, further improving the water quality of the effluent.

[0062] There are no special limitations on the device used in the treatment method of the aircraft deicing wastewater in the present invention, and a device with the above functions well-known to those skilled in the art can be used.

[0063] In the present invention, when the advanced treatment is activated carbon adsorption, the structural schematic diagram of the device used in the treatment method of the aircraft deicing wastewater is preferably as Figure 1As shown in the figure, it includes an adjustment tank (for oil removal and filtration), an evaporation tank, an air-cooled condenser, a compressor, a vacuum cooling system, and an activated carbon column; the air-cooled condenser is connected to the evaporation tank and the vacuum cooling system, the vacuum cooling system is connected to the evaporation tank, the compressor is connected to the evaporation tank and the vacuum cooling system, and preferably a refrigerant is contained inside the compressor; the adjustment tank is connected to the evaporation tank, and a raw water inlet is provided on one side of the adjustment tank; a steam outlet is provided on the upper part of one side of the evaporation tank, the steam outlet is connected to the vacuum condensation system, a concentrated liquid outlet is provided at the bottom of the evaporation tank, a distilled water outlet is provided in the vacuum condensation system, and the distilled water enters the activated carbon column. The specific working process is as follows: The raw water (aircraft deicing wastewater) enters the adjustment tank through the raw water inlet for pretreatment, and then enters the evaporation tank for low-temperature evaporation and concentration. The vacuum condensation system evacuates to reduce the pressure inside the evaporation tank. The compressor compresses the refrigerant to generate heat to heat the raw water, generating steam. The steam enters the vacuum condensation system and is liquefied by cooling to obtain distilled water, which flows out from the distilled water outlet. The concentrated liquid inside the evaporation tank flows out through the concentrated liquid outlet at the bottom of the evaporation tank, and the distilled water enters the activated carbon column for in-depth treatment.

[0064] In the present invention, the macroscopic view of the device used in the low-temperature evaporation and concentration process in the treatment method of the aircraft deicing wastewater is preferably as Figure 2 shown.

[0065] The device provided by the present invention is simple, convenient to operate, can be automated, and is convenient for operation and maintenance.

[0066] The present invention performs low-temperature evaporation and concentration on the aircraft deicing wastewater. Compared with traditional high-temperature evaporation, it greatly reduces energy consumption and operating costs. The distilled water after low-temperature evaporation and concentration is subjected to in-depth treatment, and each treatment parameter is controlled to make the effluent meet the discharge or reuse standard.

[0067] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0068] For the aircraft deicing wastewater of an airport (the airport uses the CleanwingI aircraft deicing fluid of Xi'an High-Tech Physical and Chemical Technology Co., Ltd. Affected by climate and usage conditions, the actual content of ethylene glycol in its wastewater ranges from 10wt% to 30wt%, and the COD value is 70661 - 211983mg / L), the aircraft deicing wastewater with an ethylene glycol content of 10wt% is taken as aircraft deicing wastewater 1.

[0069] Take the aircraft deicing wastewater with an ethylene glycol content of 30 wt% as aircraft deicing wastewater 2.

[0070] Example 1

[0071] A treatment method for aircraft deicing wastewater: (1) Take 100 mL of aircraft deicing wastewater 1, remove oil through an oil skimmer, and then filter it through a quartz sand filter tank. The diameter of the quartz sand is 0.5 - 1 mm, the thickness of the filter layer composed of quartz sand is 0.9 m. After removing impurities, it is loaded into a rotary evaporator, and the vacuum pump is used to pump the vacuum to a pressure of -100 kPa. The rotary evaporator is heated to 37 °C for low-temperature evaporation and concentration for 30 min. The steam is condensed by a condenser to obtain distilled water, and the remaining substances obtain a concentrated solution;

[0072] (2) Pack coconut shell activated carbon into a columnar filter, and then pass the distilled water obtained in step (1) through the columnar filter for activated carbon adsorption treatment. The particle size of the coconut shell activated carbon is 20 - 50 mesh, the pore diameter is 0.7 - 1.2 nm, the porosity is 0.5 - 0.7 cm 3 / g, the specific surface area is > 1200 m 2 / g, the thickness of the activated carbon layer is 1 m, the flow rate of the distilled water is 0.1 m / h, the pH value of the distilled water is 6 - 7, the temperature is 25 °C, and it directly enters the activated carbon column for adsorption to obtain purified water.

[0073] The chemical properties of aircraft deicing wastewater 1 and the distilled water and concentrated solution obtained in step (1) in Example 1 are shown in Table 1.

[0074] Table 1 Chemical properties of aircraft deicing wastewater 1 and the distilled water and concentrated solution obtained in step (1) in Example 1

[0075] COD mg / L TN mg / L TP mg / L Ammonia nitrogen mg / L Aircraft deicing wastewater 1 70661 105.28 0.217 3.64 Average concentration of concentrated liquid 1100067 2312.38 Average concentration of distilled water 3300 33.19

[0076] The average COD value of the purified water obtained in step (2) of Example 1 is 145 mg / L.

[0077] Example 2

[0078] A treatment method for aircraft deicing wastewater, using Figure 2The device shown is as follows: (1) The aircraft deicing wastewater 1 enters the regulating tank through the raw water inlet, is degreased by an oil skimmer, and then filtered through a quartz sand filter tank. The diameter of the quartz sand is 0.5 - 1 mm, and the thickness of the filter layer composed of quartz sand is 0.9 m. After removing impurities, it is introduced into the evaporation tank, and the vacuum is pumped to make the pressure in the evaporation tank -98 kPa. The compressor starts to work to make the temperature in the evaporation tank 37°C. The water inflow is adjusted by the liquid level gauge in the evaporation tank of the low-temperature evaporation concentration equipment. When it is lower than the bottom liquid level in the evaporation tank (near the upper part of the heating coil), the equipment automatically fills with water. When it is higher than the top liquid level in the evaporation tank, the equipment stops filling with water and conducts continuous treatment for 25 h. The steam is condensed to obtain distilled water, and the remaining substances obtain concentrated liquid;

[0079] (2) Fill the columnar filter with coconut shell activated carbon, and then pass the distilled water obtained in step (1) through the columnar filter for activated carbon adsorption treatment. The particle size of the coconut shell activated carbon is 20 - 50 mesh, the pore diameter is 0.7 - 1.2 nm, the porosity is 0.5 - 0.7 cm 3 / g, and the specific surface area is > 1200 m 2 / g. The thickness of the activated carbon layer is 1 m, the flow rate of the distilled water is 0.1 m / h, the pH value of the distilled water is 6 - 7, and the temperature is between 25 - 30°C. It directly enters the activated carbon column for adsorption to obtain purified water.

[0080] The change curve of the ethylene glycol content in the concentrated liquid at different times in step (1) of Example 2 is as Figure 3 shown, and the ethylene glycol concentration ratio is as Figure 4 shown. It can be seen from Figure 3 that when processing for 1 h, 3 h, 6 h, 10 h, 13 h, 16 h, 19 h, 22 h, and 25 h, the ethylene glycol contents in the concentrated liquid are 132132 ug / g, 160403 ug / g, 240918 ug / g, 262715 ug / g, 333009 ug / g, 375669 ug / g, 427204 ug / g, 536137 ug / g, and 661507 ug / g respectively. During the 25-h processing, the ethylene glycol content in the concentrated liquid of the aircraft deicing wastewater (initial mass concentration of ethylene glycol 10%) gradually rises from the initial 132132 ug / g to 661507 ug / g. The data shows that with the extension of the processing time, the ethylene glycol concentration in the concentrated liquid increases significantly, especially showing an accelerating upward trend in the later stage (from 427204 ug / g to 661507 ug / g).

[0081] It can be seen from Figure 4It can be seen that when processed for 1h, 3h, 6h, 10h, 13h, 16h, 19h, 22h, and 25h, the ethylene glycol concentration rates are 16.09%, 19.53%, 29.34%, 31.99%, 40.55%, 45.75%, 52.03%, 65.29%, and 80.56% respectively. The concentration rate gradually increases from 16.09% to 80.56% (corresponding to 25h). The growth trend of the concentration rate is consistent with the increase in the ethylene glycol content, indicating that the treatment process can effectively concentrate ethylene glycol. It should be noted that the increase in the concentration rate is relatively large in the later stage (from 65.29% to 80.56%), indicating that there is still significant room for improvement in the treatment efficiency after long-term operation.

[0082] In Example 2, the change curve of the ethylene glycol content in distilled water at different times in step (1) is as Figure 5 shown. As can be seen from Figure 5 it, when processed for 10h, 13h, 16h, 19h, 22h, and 25h, the ethylene glycol contents in the distilled water are 426.96 ug / g, 503.59 ug / g, 977.79 ug / g, 1436.32 ug / g, 1570.13 ug / g, and 1637.47 ug / g respectively. The ethylene glycol in the distilled water increases with time.

[0083] The COD value of the purified water obtained in step (2) of Example 2 is generally lower than 200 mg / L.

[0084] Test Example 1

[0085] Take 100 mL of aircraft deicing wastewater 2, remove oil through an oil skimmer, then filter it through a quartz sand filter. The diameter of the quartz sand is 0.5 - 1 mm, and the thickness of the filter layer composed of quartz sand is 0.9 m. After removing impurities, load it into a rotary evaporator, evacuate to a pressure of -100 kPa with a vacuum pump, heat the rotary evaporator to 37 °C for low-temperature evaporation and concentration for 25 min. The steam is condensed by a condenser to obtain distilled water, and the remaining substances obtain a concentrated solution.

[0086] Comparative Test Example 1

[0087] Take 100 mL of aircraft deicing wastewater 2, remove oil through an oil skimmer, then filter it through a quartz sand filter. The diameter of the quartz sand is 0.5 - 1 mm, and the thickness of the filter layer composed of quartz sand is 0.9 m. After removing impurities, heat it at 100 °C for 25 min. The steam is condensed to obtain distilled water, and the remaining substances obtain a concentrated solution.

[0088] The treatment capacity in Comparative Test 1 is 2 m 3 / h; the steam consumption is 120 kg of steam / m 3Wastewater, but the energy consumption is relatively high at 4.2 kWh / kg of ethylene glycol, while the energy consumption in Test Example 1 is 1 kWh / kg of ethylene glycol. Compared with Comparative Test Example 1, the treatment method of the present invention can greatly reduce the energy consumption.

[0089] The content of ethylene glycol and the COD value of distilled water in the concentrates of Test Example 1 and Comparative Test Example 1 are shown in Table 2.

[0090] Table 2 Content of ethylene glycol and COD value of distilled water in the concentrates of Test Example 1 and Comparative Test Example 1

[0091] Time Ethylene glycol in concentrated liquid COD of distilled water Comparative test example 1 25 min 800067 mg / L 12200 mg / L Test example 1 25 min 1055457 mg / L 4377 mg / L

[0092] As can be seen from Table 2, under the same time and the same aircraft deicing wastewater, the concentration effect of ethylene glycol in the aircraft deicing wastewater in Test Example 1 (low-temperature and low-pressure distillation) is significantly better than that in Comparative Test Example 1 (high-temperature and atmospheric-pressure distillation), and the effluent COD is significantly lower than that in Comparative Test Example 1.

[0093] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for treating aircraft deicing wastewater, comprising the following steps: (1) Low-temperature evaporation and concentration of the aircraft deicing wastewater followed by condensation to obtain distilled water; the temperature of the low-temperature evaporation and concentration is 35 - 50 °C; (2) Deep treatment of the distilled water obtained in step (1) to obtain purified water.

2. The processing method according to claim 1, characterized in that In step (1), the pressure of the low-temperature evaporation and concentration is -100 to -98 kPa.

3. The processing method according to claim 1 or 2, characterized in that, In step (1), the temperature of the low-temperature evaporation and concentration is 35 - 45 °C.

4. The processing method according to claim 1, wherein The deep treatment in step (2) includes one or more of activated carbon adsorption, reverse osmosis, and ozone oxidation.

5. The processing method according to claim 4, characterized in that The particle size of the activated carbon is 20 to 50 mesh, the pore diameter of the activated carbon is 0.7 to 1.2 nm, the porosity of the activated carbon is 0.5 to 0.7 cm 3 / g, and the specific surface area of the activated carbon > 1200 m 2 / g.

6. The processing method according to claim 4, characterized in that, The pressure of the reverse osmosis is 15 to 30 bar, the flux of the reverse osmosis is 20 to 50 L / m 2 ·h, and the temperature of the reverse osmosis is 15 to 35 °C.

7. The processing method according to claim 4, characterized in that For the ozone oxidation, the pH value > 9, the ozone oxidation time is 1 - 3 h, and the ozone oxidation temperature is 25 - 35 °C.

8. The processing method according to claim 7, wherein Hydrogen peroxide is also added during the ozone oxidation.

9. The processing method according to claim 8, wherein The mass concentration of the hydrogen peroxide is 30%.

10. The processing method according to claim 9, characterized in that, The volume ratio of the hydrogen peroxide to the distilled water is 1:(200 - 500).

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