A method and system for treating high-organic, high-color, high-salinity wastewater

Abstract

The application provides a high-organic, high-color and high-salt wastewater treatment method and system. The method comprises the following steps: sequentially subjecting the wastewater to air floatation treatment, softening and coupling coagulation treatment, adsorption and coupling coagulation treatment, oxidation treatment, ultrafiltration treatment and evaporation treatment, and discharging the obtained condensate. The system comprises an air floatation unit, a softening and coupling coagulation unit, an adsorption and coupling coagulation unit, an oxidation unit, an ultrafiltration unit and an evaporation unit connected in sequence. The wastewater treatment method and system can significantly reduce the organic matter concentration of evaporation feed water, thereby solving the problem of serious foaming in the evaporation process, and can effectively reduce the color, inorganic scale ion concentration, ammonia nitrogen and suspended substance content of the bubble drainage, thereby improving the water quality of the effluent, so that the effluent treated by the application can be discharged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial wastewater treatment, in particular to a high-organic, high-color and high-salt wastewater treatment method and system. BACKGROUND

[0002] In the middle and late stages of gas field well exploitation, due to the decrease of formation pressure, i.e. the decrease of lifting energy, the well bottom liquid accumulation cannot be discharged in time, which causes the water flooding of gas well and reduces the natural gas production, even causes the water flooding of production, and seriously affects the ultimate recovery of gas field. In order to solve the problem that the well bottom liquid accumulation cannot be discharged in time, the foam drainage (referred to as "foam drainage") gas recovery technology is the most widely used drainage gas recovery technology at present due to its low cost and quick effect. The principle of foam drainage technology is to inject a large amount of foaming agent (such as betaine) into the well, when the well bottom water contacts with the foaming agent, a large amount of low-density water-containing foam is generated under the agitation of gas flow, so as to improve the water carrying capacity of gas and lift the well bottom liquid accumulation to the ground. However, due to the addition of foaming agent, the foam drainage has stubborn foaming property, and the content of organic matter, ammonia nitrogen, suspended solids, salinity, calcium and magnesium ions, chloride ions and color is high, if directly discharged, it will cause great harm to the external environment.

[0003] At present, the foam drainage mainly passes through pretreatment (softening + coagulation) + membrane treatment + evaporation treatment, and the evaporation condensate is discharged into the external environment after reaching the standard, wherein the evaporation unit is mainly used for treating a large amount of membrane concentrated liquid, so the evaporation is the key unit for the stable and standard discharge of the treated water in the whole process. Since the existing process cannot effectively reduce the organic matter, ammonia nitrogen and color in the foam drainage, the color, organic matter and ammonia nitrogen content of the evaporation unit inlet water is high, the evaporation unit foams seriously, the evaporation effluent water quality is poor, and exceeds the standard for external discharge. Therefore, it is urgent to develop a foam drainage standard discharge treatment process, especially a treatment technology which can effectively reduce the color, organic matter and ammonia nitrogen of the evaporation unit inlet water, solve the problem of serious foaming of the evaporation unit, make the evaporation effluent water quality reach the standard, and thus solve the problem of harmless treatment of oil and gas field wastewater. SUMMARY

[0004] In order to solve the above technical problems, the purpose of the present application is to provide a high-organic, high-color and high-salt wastewater treatment method and system. The wastewater treatment method and system provided by the present application can especially treat the high-organic, high-color and high-salt foam drainage, and can make the treated effluent water reach the standard.

[0005] In order to achieve the above purpose, the first aspect of the present application provides a high-organic, high-color and high-salt wastewater treatment method, which comprises the following steps:

[0006] (1) subjecting the wastewater to air flotation treatment to obtain a liquid after air flotation treatment;

[0007] (2) softening and coupling coagulation treatment is performed on the liquid after the air floatation treatment to obtain a liquid after softening and coupling coagulation treatment;

[0008] (3) adsorption and coupling coagulation treatment is performed on the liquid after the softening and coupling coagulation treatment to obtain a liquid after adsorption and coupling coagulation treatment;

[0009] (4) oxidation treatment is performed on the liquid after the adsorption and coupling coagulation treatment to obtain a liquid after oxidation treatment;

[0010] (5) ultrafiltration treatment is performed on the liquid after the oxidation treatment to obtain a liquid after ultrafiltration treatment;

[0011] (6) evaporation treatment is performed on the liquid after the ultrafiltration treatment to obtain a condensed liquid which meets the discharge standard.

[0012] In the above method, preferably, the wastewater is foam drainage.

[0013] In the above method, preferably, step (1) specifically comprises: the wastewater enters an air floatation unit, air is introduced into the wastewater to treat the wastewater, and scum formed on the liquid surface is scraped off to obtain a liquid after air floatation treatment.

[0014] In the above method, preferably, in step (1), the device for treating the wastewater in the air floatation unit comprises an aeration tank.

[0015] In the above method, preferably, in step (1), the amount of air introduced into the wastewater is 5% to 20% (volume percentage) of the water inflow amount of the wastewater in the air floatation unit, and the hydraulic retention time of the wastewater in the air floatation unit is 5 to 20 min.

[0016] In the above method, preferably, step (1) further comprises: the sludge generated after the treatment is sent to a filter press; more preferably, the sludge generated after the treatment is discharged from the bottom of the aeration tank and sent to the filter press through a pipeline.

[0017] The air floatation adopted in the present application is dissolved air floatation, that is, air is introduced into the wastewater (foam drainage) to oxidize the reducing substances in the wastewater (foam drainage) to form precipitates, such as oxidizing divalent iron ions to trivalent iron ions to form precipitates, and to degrade part of macromolecular organic matter, mineralize part of small molecular organic matter, and sterilize (such as sulfate-reducing bacteria, saprophytic bacteria, and iron bacteria). The uniform, high-density, nanoscale air bubbles formed by air aeration can take the substances (such as petroleum, suspended matter, particles, and colloids) with a density less than water in the wastewater (foam drainage) to the upper part of the liquid to form scum, which is scraped off and removed. The present application does not make special limitation on the scraping method of the scum, and a scraper (such as a mud scraper) can be used to scrape off the scum. The sludge generated after the air floatation treatment can be discharged from the bottom of the aeration tank and sent to the filter press.

[0018] In the above method, preferably, step (2) specifically comprises: making the liquid after the air floatation treatment enter a softening-coupling coagulation unit, in which the liquid after the air floatation treatment is treated with a first softening agent, then treated with a second softening agent and a barium removal agent, and then treated with a first coagulation agent, and then treated with a first flocculation agent, and then obtained after precipitation.

[0019] In the above method, preferably, in step (2), the treatment with the first softening agent comprises: making the liquid after the air floatation treatment enter a first reaction tank, and adding the first softening agent into the first reaction tank while mechanical stirring is performed, the liquid after the air floatation treatment stays in the first reaction tank for a period of time, and then a liquid after the first softening agent treatment is obtained. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the liquid after the air floatation treatment in the first reaction tank is 8-12 min. More preferably, the liquid after the air floatation treatment enters the first reaction tank from a liquid inlet at the upper part of the first reaction tank.

[0020] In the above method, preferably, in step (2), the first softening agent comprises NaOH. More preferably, the pH value of the liquid after the first softening agent treatment is 9.5-11.5. The present application does not make special limitation on the adding amount and adding form of the first softening agent, and a person skilled in the art can make routine adjustment as long as the pH value defined in the present application is met.

[0021] In step (2) of the above method, the supernatant (i.e., the liquid after the air floatation treatment) in the aeration tank of the air floatation unit enters the first reaction tank of the softening-coupling coagulation unit, and after the treatment with the first softening agent, the magnesium ions in the liquid after the air floatation treatment (bubble drainage) form Mg(OH)2 precipitate, and the HCO3 - in the liquid after the air floatation treatment is converted into CO3 2- , and forms carbonate precipitate with part of the non-fouling cations (Ca 2+ , Sr 2+ , etc.).

[0022] In the above method, preferably, step (2), the treatment with a second softener and a barium remover includes: allowing the liquid treated with the first softener to enter a second reaction tank from the first reaction tank, and adding the second softener and the barium remover therein, while simultaneously performing mechanical stirring. The liquid treated with the first softener remains in the second reaction tank for a period of time to obtain the liquid treated with the second softener and the barium remover. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic residence time of the liquid treated with the first softener in the second reaction tank is 8-12 min. More preferably, the liquid treated with the first softener is discharged from the liquid outlet at the bottom of the first reaction tank and enters the second reaction tank through the liquid inlet at the bottom of the second reaction tank.

[0023] In the above method, preferably, in step (2), the second softening agent includes Na2CO3, and the barium removal agent includes Na2SO4. 4。

[0024] In the above method, preferably, in step (2), the dosage of the second softening agent is 1.5 to 2 times the total hardness (calculated as CaCO3, mg / L) in the wastewater (foaming drainage), and the dosage of the barium removal agent is 1.5 to 2 times the barium ion concentration in the wastewater (foaming drainage). It should be noted that the dosages of the second softening agent and the barium removal agent described in this invention are based on the amount of pure substance. Those skilled in the art should understand that the second softening agent and the barium removal agent can be added in solid form or in solution form, and the concentration of the solution can be conventionally adjusted by those skilled in the art.

[0025] In step (2) of the above method, after treatment with the second softener and barium remover, a large number of residual non-scaling cations (Ca) remain in the liquid (foam drain) after treatment with the first softener. 2+ Ba 2+ (etc.) form carbonate and sulfate precipitates. The softener used in this invention avoids the shortcomings of commonly used wastewater softening agents such as lime (Ca(OH)2). These shortcomings include low removal rate of inorganic scale ions if the lime dosage is too low, and excessive dosage leading to the formation of Ca(OH)2 precipitates in the lime. 2+ Instead, it increases the concentration of residual inorganic scale ions. The barium removal agent used in this invention has a better removal effect than conventional barium removal agents (such as Na2CO3).

[0026] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0027] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0029] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0029] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0029] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0029] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant into the third reaction tank, and carrying out mechanical stirring, and the second softening and barium removal treated liquid stays in the third reaction tank for a period of time to obtain a first coagulant treated liquid. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the second softening and barium removal treated liquid in the third reaction tank is 5-10 min. More preferably, the second softening and barium removal treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and enters the third reaction tank through the liquid inlet at the upper part of the third reaction tank.

[0029] In the above method, preferably, in step (2), the first coagulant comprises polyaluminum chloride (PAC). More preferably, the dosage of the first coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal treated liquid). The dosage of the first coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0028] In the above method, preferably, in step (2), the treatment with the first coagulant comprises: feeding the second softening and barium removal treated liquid from the second reaction tank into a third reaction tank, adding the first coagulant

[0030] In the above method, preferably, in step (2), the softened and coagulated treated liquid is obtained by: making the first flocculant treated liquid from the fourth reaction tank into a first inclined plate sedimentation tank, and staying in the first inclined plate sedimentation tank for a period of time for sedimentation, to obtain the softened and coagulated treated liquid. More preferably, the first flocculant treated liquid stays in the first inclined plate sedimentation tank for 20-40 min. More preferably, the first flocculant treated liquid is discharged from the liquid outlet in the middle of the fourth reaction tank and enters the first inclined plate sedimentation tank through the liquid inlet of the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is arranged on the side wall of the first inclined plate sedimentation tank and slightly below the inclined plate.

[0031] In the above method, preferably, step (2) further comprises: sending the sludge generated in the first reaction tank, and / or the second reaction tank, and / or the third reaction tank, and / or the fourth reaction tank, and / or the first inclined plate sedimentation tank to a filter press; more preferably, the sludge generated in the first reaction tank, and / or the second reaction tank, and / or the third reaction tank, and / or the fourth reaction tank, and / or the first inclined plate sedimentation tank is discharged from the sludge outlet at the bottom of the tank and sent to the filter press through the pipeline.

[0032] The present application performs softened and coagulated treatment on the air floatation treated liquid, first performs softened and sedimentation treatment to remove scale-forming ions such as calcium, magnesium, barium, strontium, etc., and then performs coagulation, flocculation, and sedimentation to reduce the suspended solids, colloids, inorganic scale, organic matter, turbidity, etc. in the air floatation treated liquid (foam drainage), and the sludge generated in the softened and coagulated unit can be sent to a filter press.

[0033] In the above method, preferably, step (3) specifically comprises: making the softened and coagulated treated liquid into an adsorption and coagulation unit, adjusting the pH value of the softened and coagulated treated liquid with a first pH adjuster in the adsorption and coagulation unit, then treating it with an adsorbent, then treating it with a second coagulant, then treating it with a second flocculant, and then obtaining the adsorption and coagulation treated liquid after sedimentation.

[0034] In the above method, preferably, in step (3), the treatment of the softened and coagulated liquid with the first pH regulator to adjust the pH value and then with the adsorbent comprises: the softened and coagulated liquid enters a fifth reaction tank, the first pH regulator is added to adjust the pH value of the liquid to 5-6.5, the adsorbent is then added, and mechanical stirring is performed, the softened and coagulated liquid stays in the fifth reaction tank for a period of time, and an adsorbent-treated liquid is obtained. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the softened and coagulated liquid in the fifth reaction tank is 20-40 min. More preferably, the softened and coagulated liquid is discharged from the liquid outlet of the first inclined plate sedimentation tank and enters the fifth reaction tank through the liquid inlet at the bottom of the fifth reaction tank.

[0035] In the above method, preferably, in step (3), the first pH regulator comprises hydrochloric acid and / or sodium hydroxide. The present application does not make special limitations on the addition amount and addition form of the first pH regulator, and those skilled in the art can make routine adjustments as long as the pH value defined in the present application is met.

[0036] In the above method, preferably, in step (3), the adsorbent comprises a combination of 3-7 kinds of coconut shell activated carbon, nutshell activated carbon, coal, quartz sand, resin, bentonite, illite, activated alumina and montmorillonite, etc. More preferably, the adsorbent comprises a combination of a first group of adsorbents, a second group of adsorbents and a third group of adsorbents; wherein the first group of adsorbents is selected from 1-3 kinds of coconut shell activated carbon, quartz sand and illite, the second group of adsorbents is selected from 1-3 kinds of nutshell activated carbon, resin, bentonite and montmorillonite, and the third group of adsorbents is selected from 1 kind of coal and activated alumina. More preferably, the addition amount of a single adsorbent is 5-100 g / L (i.e. the addition amount of each adsorbent in the softened and coagulated liquid is 5-100 g per L).

[0037] In step (3) of the above method, the supernatant of the first inclined plate sedimentation tank in the softening-coupled coagulation unit (i.e., the liquid after the softening-coupled coagulation treatment) is introduced into the fifth reaction tank of the adsorption-coupled coagulation unit, and the pH of the liquid after the softening-coupled coagulation treatment is adjusted to 5-6.5 using a pH adjuster, and then an adsorbent is added for adsorption. Under acidic conditions, the organic matter (such as betaine surfactant) in the liquid is positively charged, and the adsorbent is negatively charged, and a strong electrostatic attraction can be formed between the organic matter and the adsorbent, thereby increasing the adsorption capacity. Under alkaline conditions, the organic matter (such as betaine surfactant) in the liquid is negatively charged after being ionized, and the adsorbent has strong negative charge, and the adsorption capacity is reduced. Therefore, the liquid after the softening-coupled coagulation treatment is first adjusted to be acidic using a pH adjuster, and then an adsorbent is added for adsorption, which can increase the adsorption capacity of the adsorbent for the organic matter in the wastewater (foam drainage).

[0038] In the above method, preferably, in step (3), the treatment using the second coagulant includes: introducing the liquid after the adsorbent treatment into a sixth reaction tank, and adding a second coagulant into the sixth reaction tank while mechanical stirring is performed, the liquid after the adsorbent treatment stays in the sixth reaction tank for a period of time, and a liquid after the second coagulant treatment is obtained. More preferably, the speed of the mechanical stirring is 100-400 r / min. More preferably, the hydraulic retention time of the liquid after the adsorbent treatment in the sixth reaction tank is 5-10 min. More preferably, the liquid after the adsorbent treatment is discharged from the liquid outlet at the upper part of the fifth reaction tank and introduced into the sixth reaction tank through the liquid inlet at the upper part of the sixth reaction tank.

[0039] In the above method, preferably, in step (3), the second coagulant includes polyaluminum chloride (PAC). More preferably, the dosage of the second coagulant is 50-1000 mg / L (i.e., 50-1000 mg of the second coagulant is added per L of the liquid after the adsorbent treatment). The dosage of the second coagulant can be calculated based on the effective substance content of polyaluminum chloride. Further preferably, the polyaluminum chloride (PAC) used in the present application has a purity of 100%.

[0040] In the above method, preferably, in step (3), the treatment with the second flocculant comprises: feeding the second coagulant treated liquid into a seventh reaction tank, and adding the second flocculant into the seventh reaction tank while mechanical stirring is performed, the second coagulant treated liquid stays in the seventh reaction tank for a period of time to obtain a second flocculant treated liquid. More preferably, the speed of the mechanical stirring is 20-80 r / min. More preferably, the hydraulic retention time of the second coagulant treated liquid in the seventh reaction tank is 5-10 min. More preferably, the second coagulant treated liquid is discharged from a liquid outlet at the bottom of the sixth reaction tank and fed into the seventh reaction tank through a liquid inlet at the bottom of the seventh reaction tank.

[0041] In the above method, preferably, in step (3), the second flocculant comprises polyacrylamide (PAM). More preferably, the second flocculant comprises cationic polyacrylamide with a cationic degree of 10-60 and a molecular weight of 3 million-8 million. Further preferably, the dosage of the second flocculant is 0.05-10 mg / L (i.e. 0.05-10 mg of the second flocculant is added per L of the second coagulant treated liquid). The dosage of the second flocculant can be calculated based on the effective substance content of polyacrylamide. Further preferably, the purity of the cationic polyacrylamide used in the present application is 100%.

[0042] In the above method, preferably, in step (3), the adsorption-coupled coagulation treated liquid obtained after precipitation comprises: feeding the second flocculant treated liquid from the seventh reaction tank into a second inclined plate sedimentation tank, and allowing the second flocculant treated liquid to stay in the second inclined plate sedimentation tank for a period of time to perform precipitation, to obtain an adsorption-coupled coagulation treated liquid. More preferably, the second flocculant treated liquid stays in the second inclined plate sedimentation tank for 20-40 min. More preferably, the second flocculant treated liquid is discharged from a liquid outlet in the middle of the seventh reaction tank and fed into the second inclined plate sedimentation tank through a liquid inlet of the second inclined plate sedimentation tank, and the liquid inlet of the second inclined plate sedimentation tank is arranged on the side wall of the second inclined plate sedimentation tank and slightly lower than the inclined plate.

[0043] In the above method, preferably, step (3) further comprises: feeding the sludge generated in the fifth reaction tank, and / or the sixth reaction tank, and / or the seventh reaction tank, and / or the second inclined plate sedimentation tank to a filter press; more preferably, the sludge generated in the fifth reaction tank, and / or the sixth reaction tank, and / or the seventh reaction tank, and / or the second inclined plate sedimentation tank is discharged from a sludge outlet at the bottom of the tank and fed to the filter press through a pipeline.

[0044] The application is to soften the coupling coagulation treated liquid to carry out adsorption coupling coagulation treatment, to carry out adsorption, coagulation, flocculation and precipitation in the adsorption coupling coagulation unit, so as to further reduce the suspended solids, colloids, organic matter, turbidity, color and the like in the wastewater (foam drainage), and the sludge generated in the adsorption coupling coagulation unit can be sent to the filter press.

[0045] In the above method, preferably, step (4) specifically comprises: making the adsorption coupling coagulation treated liquid enter an oxidation reactor in the oxidation unit, adding a second pH adjuster to adjust the pH value of the liquid to 5-6, and then adding a first oxidizing agent and a second oxidizing agent in sequence, and the adsorption coupling coagulation treated liquid stays in the oxidation reactor for a period of time, and is subjected to oxidation treatment under the action of ultraviolet and ultrasonic waves in the oxidation reactor to obtain the oxidation treated liquid.

[0046] In the above method, preferably, in step (4), the second pH adjuster comprises hydrochloric acid and / or sodium hydroxide and the like. The application does not make special limitation to the adding amount and adding form of the second pH adjuster, and the person skilled in the art can make routine adjustment as long as the pH value defined in the application is met.

[0047] In the above method, preferably, in step (4), the first oxidizing agent comprises Na2S2O8, and the second oxidizing agent comprises H2O2. More preferably, the molar ratio of the adding amount of the first oxidizing agent to the second oxidizing agent is (1-4):1, and the ratio of the adding amount of the second oxidizing agent to the COD concentration of the treated wastewater (foam drainage) is (0.6-2):1.

[0048] In the above method, preferably, in step (4), the frequency of the ultrasonic wave in the oxidation reactor is 20-28 kHz, and the power is 50-250 W; the wavelength of the ultraviolet in the oxidation reactor is 185-400 nm, and the power is 3-55 W. More preferably, the ultraviolet and the ultrasonic wave in the oxidation reactor are respectively generated by the immersed ultraviolet lamp and the immersed ultrasonic instrument arranged in the oxidation reactor.

[0049] In the above method, preferably, in step (4), the oxidation treatment is carried out under mechanical stirring, and the speed of the mechanical stirring is 30-80 r / min.

[0050] In the above method, preferably, in step (4), the adsorption coupling coagulation treated liquid stays in the oxidation reactor for 20-60 min.

[0051] In step (4) of the above method, the supernatant of the second inclined plate sedimentation tank in the adsorption-coupled coagulation unit (i.e., the liquid after adsorption-coupled coagulation treatment) is introduced into the oxidation reactor in the oxidation unit for treatment. First, a second pH regulator is used to adjust the pH value of the liquid to 5-6, and then a first oxidant Na2S2O8 and a second oxidant H2O2 are sequentially added. This is because, under acidic conditions, Na2S2O8 is easily activated to generate sulfate radicals (SO4 - ·) with strong oxidizing properties, and H2O2 generates hydroxyl radicals (OH·) with strong oxidizing properties. Meanwhile, the oxidation reactor is provided with an immersed ultraviolet lamp and an immersed ultrasonic instrument. Oxidation treatment is carried out under the action of ultraviolet light and ultrasound. Since ultraviolet light and ultrasound can both enhance the generation of sulfate radicals (SO4 - ·) and hydroxyl radicals (OH·), they can promote oxidation and help remove organic matter and ammonia nitrogen in the wastewater (foam drainage).

[0052] The present application performs oxidation treatment on the liquid after adsorption-coupled coagulation treatment, and further reduces organic matter, bacteria, color, ammonia nitrogen, etc. in the wastewater (foam drainage) after deep treatment in the oxidation unit.

[0053] In the above method, preferably, step (5) specifically comprises: introducing the liquid after oxidation treatment into an ultrafiltration device of an ultrafiltration unit, and adding a third pH regulator in the ultrafiltration device to adjust the pH value of the liquid to neutral to obtain a liquid after ultrafiltration treatment. The ultrafiltration device can use a conventional ultrafiltration membrane device in the field of wastewater treatment. More preferably, the liquid after oxidation treatment is discharged from the liquid outlet at the upper part of the oxidation reactor and enters the ultrafiltration device through the liquid inlet of the ultrafiltration device.

[0054] In the above method, preferably, in step (5), the third pH regulator includes hydrochloric acid and / or sodium hydroxide, etc. The present application does not make special limitations on the addition amount and addition form of the third pH regulator, and those skilled in the art can make routine adjustments as long as the pH value defined in the present application is met.

[0055] The present application performs ultrafiltration treatment on the liquid after oxidation treatment, and further removes impurities in the wastewater (foam drainage) by filtering the liquid in the ultrafiltration unit.

[0056] In the above method, preferably, step (6) specifically comprises: making the liquid after the ultrafiltration treatment enter an evaporation unit, and performing evaporation in a steam mechanical recompression device (MVR) to obtain a condensate that meets the discharge standard. More specifically, the condensate meets the first level standard of the “Integrated Wastewater Discharge Standard” (GB 8978-1996) and the first level standard of the “Sichuan Province Water Pollutant Discharge Standard” (DB 51190-93).

[0057] The present application performs evaporation treatment on the liquid after the ultrafiltration treatment, and performs desalination treatment on the liquid in the evaporation unit to obtain a condensate that meets the discharge standard.

[0058] The second aspect of the present application provides a high-organic-matter, high-colority, and high-salt wastewater treatment system, which is used to implement the above-mentioned high-organic-matter, high-colority, and high-salt wastewater treatment method. The system comprises, in sequence, an air flotation unit, a softening and coupling coagulation unit, an adsorption and coupling coagulation unit, an oxidation unit, an ultrafiltration unit, and an evaporation unit.

[0059] In the above system, preferably, the air flotation unit comprises an aeration tank. More preferably, the upper part of the aeration tank is provided with a scraper. More preferably, the air flotation unit further comprises an air compressor connected to the bottom of the aeration tank through a pipeline for introducing air into the aeration tank. Further preferably, the bottom of the aeration tank is provided with a sludge discharge pipe connected to an external filter press for discharging sludge from the bottom of the aeration tank to the filter press.

[0060] In the above system, preferably, the softening and coupling coagulation unit comprises, in sequence, a first reaction tank, a second reaction tank, a third reaction tank, a fourth reaction tank, and a first inclined plate sedimentation tank. More preferably, the upper middle part of the first reaction tank is provided with a liquid inlet for making the liquid after the air flotation treatment from the air flotation unit enter the first reaction tank; the liquid outlet at the bottom of the first reaction tank is connected to the liquid inlet at the bottom of the second reaction tank; the liquid outlet at the upper middle part of the second reaction tank is connected to the liquid inlet at the upper middle part of the third reaction tank; the liquid outlet at the bottom of the third reaction tank is connected to the liquid inlet at the bottom of the fourth reaction tank; and the liquid outlet at the middle part of the fourth reaction tank is connected to the liquid inlet of the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is arranged on the side wall of the first inclined plate sedimentation tank and is lower than (slightly lower than) the position of the inclined plate.

[0061] In the above system, preferably, the first reaction tank, the second reaction tank, the third reaction tank, and the fourth reaction tank are provided with stirrers inside for mechanically stirring the liquid therein. The specific structure and arrangement of the stirrers can adopt the conventional techniques in the art, and the present application does not make special limitations thereon.

[0062] In the system, preferably, the bottom of the first reaction tank, and / or the second reaction tank, and / or the third reaction tank, and / or the fourth reaction tank, and / or the first inclined plate sedimentation tank is provided with a sludge discharge pipe connected to an external filter press for discharging sludge from the bottom of the tank and sending it to the filter press.

[0063] In the system, preferably, the adsorption-coupled coagulation unit comprises a fifth reaction tank, a sixth reaction tank, a seventh reaction tank and a second inclined plate sedimentation tank connected in sequence. More preferably, the bottom of the fifth reaction tank is provided with a liquid inlet for allowing softened water from the softening-coupled coagulation unit to enter the fifth reaction tank after softening-coupled coagulation treatment; the liquid outlet at the upper part of the fifth reaction tank is connected to the liquid inlet at the upper part of the sixth reaction tank; the liquid outlet at the bottom of the sixth reaction tank is connected to the liquid inlet at the bottom of the seventh reaction tank; the liquid outlet at the middle part of the seventh reaction tank is connected to the liquid inlet of the second inclined plate sedimentation tank, and the liquid inlet of the second inclined plate sedimentation tank is provided on the side wall of the second inclined plate sedimentation tank and is lower than (slightly lower than) the inclined plate.

[0064] In the system, preferably, the fifth reaction tank, the sixth reaction tank and the seventh reaction tank are provided with a stirrer inside for mechanically stirring the liquid therein. The specific structure and arrangement of the stirrer can be conventional in the art, and the present application does not make special limitations thereon.

[0065] In the system, preferably, the bottom of the fifth reaction tank, and / or the sixth reaction tank, and / or the seventh reaction tank, and / or the second inclined plate sedimentation tank is provided with a sludge discharge pipe connected to an external filter press for discharging sludge from the bottom of the tank and sending it to the filter press.

[0066] In the system, preferably, the oxidation unit comprises an oxidation reactor provided with an immersed ultraviolet lamp and an immersed ultrasonic device inside. The immersed ultraviolet lamp and the immersed ultrasonic device can be conventional devices in the art, and the present application does not make special limitations on their structures. More preferably, the oxidation reactor is further provided with a stirrer inside for mechanically stirring the liquid therein. The specific structure and arrangement of the stirrer can be conventional in the art, and the present application does not make special limitations thereon. More specifically, the side wall of the oxidation reactor is provided with a liquid inlet and a liquid outlet, the liquid inlet can be located at the middle-lower part of the side wall of the oxidation reactor, the liquid outlet can be located at the middle-upper part of the side wall of the oxidation reactor, and the liquid inlet and the liquid outlet are oppositely arranged on the side wall of the oxidation reactor.

[0067] In the above system, preferably, the ultrafiltration unit comprises an ultrafiltration device. The ultrafiltration device can be a conventional ultrafiltration membrane device in the field of wastewater treatment.

[0068] In the above system, preferably, the evaporation unit comprises a mechanical vapor recompression device (MVR).

[0069] The present application provides a high-organic, high-color, and high-salt wastewater treatment method and system, in particular, a high-organic, high-color, and high-salt foam drainage treatment method and system. The method of the present application mainly processes the foam drainage through a gas flotation unit, a softening-coupled coagulation unit, an adsorption-coupled coagulation unit, an oxidation unit, an ultrafiltration unit, and an evaporation unit. The method can stably and completely solve the problems of high-organic, high-color, and high-salt foam drainage, effectively reduce the color, inorganic scale ion concentration, suspended solids, organic matter, and ammonia nitrogen content in the foam drainage, improve the water quality of the evaporation unit, solve the problem of severe foaming in the evaporation unit, and stabilize the COD, color, suspended solids, chloride ion, ammonia nitrogen, etc. of the treated evaporation effluent to reach the first-level standard in the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the "Sichuan Water Pollutant Discharge Standard" (DB 51190-93).

[0070] The high-organic, high-color, and high-salt wastewater treatment method and system provided by the present application have at least the following excellent technical effects:

[0071] (1) The organic matter concentration of the evaporation influent can be significantly reduced, thereby solving the problem of severe foaming in the evaporation process;

[0072] (2) The color, inorganic scale ion concentration, ammonia nitrogen, and suspended solids content of the foam drainage can be effectively reduced, thereby improving the effluent water quality;

[0073] (3) The COD, color, suspended solids, chloride ion, ammonia nitrogen, etc. of the treated effluent stably reach the first-level standard in the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the "Sichuan Water Pollutant Discharge Standard" (DB 51190-93). BRIEF DESCRIPTION OF DRAWINGS

[0074] Figure 1 The flow and structure schematic diagram of the high-organic, high-color, and high-salt foam drainage treatment method and system provided by the present application for a specific embodiment. DETAILED DESCRIPTION

[0075] In order to have a clearer understanding of the technical features, objectives, and beneficial effects of the present application, the technical solutions of the present application are described in detail below, but it cannot be understood as limiting the implementable scope of the present application.

[0076] In a preferred embodiment of the present application, the present application provides a high-organic-matter, high-colority, high-salt foam drainage treatment method, a flow chart of which is shown in Fig. 1, and the method comprises the following steps: Figure 1

[0077] (1) The foam drainage is fed into an aeration tank of a flotation unit, air is introduced into the foam drainage for treatment, the amount of air introduced is 5% to 20% of the water inflow of the foam drainage in the flotation unit, the hydraulic retention time of the foam drainage in the flotation unit is 5 to 20 min, then the scum formed on the liquid surface in the aeration tank is scraped off by a scraper (such as a mud scraping plate) to obtain a liquid after flotation treatment, and the sludge generated after treatment is discharged from the bottom of the aeration tank and sent to a filter press through a pipeline;

[0078] (2) The liquid after flotation treatment (i.e., the supernatant in the aeration tank) is fed into a first reaction tank of a softening-coupled coagulation unit, a first softening agent NaOH is added thereto, and mechanical stirring is performed at the same time, the speed of mechanical stirring is 100 to 400 r / min, the hydraulic retention time of the liquid after flotation treatment in the first reaction tank is 8 to 12 min, a liquid after first softening agent treatment is obtained, and the pH value of the liquid after first softening agent treatment is 9.5 to 11.5; more specifically, the liquid after flotation treatment is fed into the first reaction tank from the liquid inlet at the upper part of the first reaction tank;

[0079] The liquid after first softening agent treatment is further fed from the first reaction tank into a second reaction tank, a second softening agent Na2CO3 and a barium removal agent Na2SO4 are added thereto, the addition amount of the second softening agent Na2CO3 is 1.5 to 2 times the total hardness (in terms of CaCO3, mg / L) in the foam drainage, the addition amount of the barium removal agent Na2SO4 is 1.5 to 2 times the barium ion concentration in the foam drainage, mechanical stirring is performed at the same time, the speed of mechanical stirring is 100 to 400 r / min, the hydraulic retention time of the liquid after first softening agent treatment in the second reaction tank is 8 to 12 min, and a liquid after second softening agent and barium removal agent treatment is obtained; more specifically, the liquid after first softening agent treatment is discharged from the liquid outlet at the bottom of the first reaction tank and fed into the second reaction tank through the liquid inlet at the bottom of the second reaction tank;

[0080] ​The second softening and barium removal agent treated liquid is then fed from the second reaction tank into a third reaction tank, and a first coagulant, polyaluminum chloride (PAC), is added thereto, the addition amount of the first coagulant being 50-1000 mg / L (i.e. 50-1000 mg of the first coagulant is added per L of the second softening and barium removal agent treated liquid), the polyaluminum chloride (PAC) used having a purity of 100%, and mechanical stirring is carried out at a speed of 100-400 r / min, the hydraulic retention time of the second softening and barium removal agent treated liquid in the third reaction tank being 5-10 min, to obtain a first coagulant treated liquid; more specifically, the second softening and barium removal agent treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and fed into the third reaction tank through the liquid inlet at the upper part of the third reaction tank;

[0081] The first coagulant treated liquid is then fed from the third reaction tank into a fourth reaction tank, and a first flocculant is added thereto, the first flocculant being anionic polyacrylamide with a molecular weight of 8-15 million, the addition amount of the first flocculant being 0.05-10 mg / L (i.e. 0.05-10 mg of the first flocculant is added per L of the first coagulant treated liquid), the anionic polyacrylamide used having a purity of 100%, and mechanical stirring is carried out at a speed of 20-80 r / min, the hydraulic retention time of the first coagulant treated liquid in the fourth reaction tank being 5-10 min, to obtain a first flocculant treated liquid; more specifically, the first coagulant treated liquid is discharged from the liquid outlet at the bottom of the third reaction tank and fed into the fourth reaction tank through the liquid inlet at the bottom of the fourth reaction tank;

[0082] The first flocculant treated liquid is then fed from the fourth reaction tank into a first inclined plate sedimentation tank, and is allowed to settle in the first inclined plate sedimentation tank for 20-40 min, to obtain a softening and coagulation treated liquid; more specifically, the first flocculant treated liquid is discharged from the liquid outlet at the middle of the fourth reaction tank and fed into the first inclined plate sedimentation tank through the liquid inlet of the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is arranged at the side wall of the first inclined plate sedimentation tank and is slightly lower than the inclined plate;

[0083] The sludge produced in the first reaction tank, the second reaction tank, the third reaction tank, the fourth reaction tank and the first inclined plate sedimentation tank is discharged from the sludge outlet at the bottom of the tank and sent to a filter press through a pipeline;

[0084] (3) the softened and coagulated liquid (i.e. supernatant in the first inclined plate sedimentation tank) is introduced into a fifth reaction tank of the adsorption and coagulation coupled unit, and a first pH adjusting agent, hydrochloric acid and / or sodium hydroxide, is added to adjust the pH of the liquid to 5-6.5, and an adsorbent is added, the adsorbent including a combination of 3-7 kinds of coconut activated carbon, nutshell activated carbon, coal, quartz sand, resin, bentonite, illite, activated alumina and montmorillonite, more preferably, the adsorbent includes a combination of a first group of adsorbents, a second group of adsorbents and a third group of adsorbents; wherein the first group of adsorbents is selected from 1-3 kinds of coconut activated carbon, quartz sand and illite, the second group of adsorbents is selected from 1-3 kinds of nutshell activated carbon, resin, bentonite and montmorillonite, and the third group of adsorbents is selected from 1 kind of coal and activated alumina, and the dosage of a single adsorbent is 5-100 g / L (i.e. the dosage of each adsorbent in the softened and coagulated liquid is 5-100 g per L), and then mechanical stirring is performed at a speed of 100-400 r / min, and the hydraulic retention time of the softened and coagulated liquid in the fifth reaction tank is 20-40 min to obtain an adsorbent-treated liquid; more specifically, the softened and coagulated liquid is discharged from the liquid outlet of the first inclined plate sedimentation tank and introduced into the fifth reaction tank through the liquid inlet at the bottom of the fifth reaction tank;

[0085] Then the adsorbent-treated liquid is introduced into a sixth reaction tank, and a second coagulant, polyaluminum chloride (PAC), is added, and the dosage of the second coagulant is 50-1000 mg / L (i.e. 50-1000 mg of the second coagulant is added per L of the adsorbent-treated liquid), and the purity of the polyaluminum chloride (PAC) used is 100%, and mechanical stirring is performed at a speed of 100-400 r / min, and the hydraulic retention time of the adsorbent-treated liquid in the sixth reaction tank is 5-10 min to obtain a second coagulant-treated liquid; more specifically, the adsorbent-treated liquid is discharged from the liquid outlet at the upper part of the fifth reaction tank and introduced into the sixth reaction tank through the liquid inlet at the upper part of the sixth reaction tank;

[0086] The second flocculant-treated liquid is then introduced into a seventh reaction tank, and a second flocculant is added thereto, the second flocculant being cationic polyacrylamide with a cationic degree of 10-60 and a molecular weight of 3 million-8 million, the second flocculant being added in an amount of 0.05-10 mg / L (i.e. 0.05-10 mg of the second flocculant is added per L of the second flocculant-treated liquid), the cationic polyacrylamide used having a purity of 100%, and mechanical stirring is performed at a speed of 20-80 r / min, the second flocculant-treated liquid being retained in the seventh reaction tank for 5-10 min to obtain a second flocculant-treated liquid; more specifically, the second flocculant-treated liquid is discharged from a liquid outlet at the bottom of the sixth reaction tank and introduced into the seventh reaction tank through a liquid inlet at the bottom of the seventh reaction tank;

[0087] The second flocculant-treated liquid is then introduced into a seventh reaction tank, and a second flocculant is added thereto, the second flocculant being cationic polyacrylamide with a cationic degree of 10-60 and a molecular weight of 3 million-8 million, the second flocculant being added in an amount of 0.05-10 mg / L (i.e. 0.05-10 mg of the second flocculant is added per L of the second flocculant-treated liquid), the cationic polyacrylamide used having a purity of 100%, and mechanical stirring is performed at a speed of 20-80 r / min, the second flocculant-treated liquid being retained in the seventh reaction tank for 5-10 min to obtain a second flocculant-treated liquid; more specifically, the second flocculant-treated liquid is discharged from a liquid outlet at the bottom of the sixth reaction tank and introduced into the seventh reaction tank through a liquid inlet at the bottom of the seventh reaction tank;

[0088] The sludge produced in the fifth reaction tank, the sixth reaction tank, the seventh reaction tank and the second inclined plate sedimentation tank is discharged from a sludge outlet at the bottom of each tank and sent to a filter press through a pipeline;

[0089] (4) the adsorption coupling coagulation treated liquid (i.e. supernatant in the second inclined plate sedimentation tank) is introduced into an oxidation reactor in the oxidation unit, and a second pH adjusting agent, hydrochloric acid and / or sodium hydroxide, is added to adjust the pH value of the liquid to 5-6, and then a first oxidizing agent, Na2S2O8, and a second oxidizing agent, H2O2, are added in sequence, the molar ratio of the first oxidizing agent to the second oxidizing agent is (1-4):1, the addition amount of the second oxidizing agent is (0.6-2):1 of the COD concentration of the treated foam drainage, the adsorption coupling coagulation treated liquid stays in the oxidation reactor for 20-60 min, and the oxidation treatment is carried out under the action of ultraviolet and ultrasonic waves in the oxidation reactor and mechanical stirring, the frequency of the ultrasonic wave in the oxidation reactor is 20-28 kHz, the power of the ultrasonic wave is 50-250 W, the wavelength of the ultraviolet is 185-400 nm, and the power of the ultraviolet is 3-55 W, the ultraviolet and the ultrasonic wave in the oxidation reactor are generated by the immersed ultraviolet lamp and the immersed ultrasonic instrument arranged in the oxidation reactor, respectively, and the speed of the mechanical stirring is 30-80 r / min, to obtain the oxidation treated liquid;

[0090] (5) the oxidation treated liquid is introduced into an ultrafiltration device in the ultrafiltration unit, the ultrafiltration device can adopt a conventional ultrafiltration membrane device in the wastewater treatment field, and a third pH adjusting agent, hydrochloric acid and / or sodium hydroxide, is added to adjust the pH value of the liquid to neutral, to obtain the ultrafiltration treated liquid; more specifically, the oxidation treated liquid is discharged from the liquid outlet at the upper part of the oxidation reactor and introduced into the ultrafiltration device through the liquid inlet of the ultrafiltration device;

[0091] (6) the ultrafiltration treated liquid is introduced into the evaporation unit, and evaporation is carried out in a steam mechanical re-compression device (MVR), and the obtained condensate is discharged up to the standard; more specifically, the condensate reaches the first level standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the first level standard of the "Sichuan Province Water Pollutant Discharge Standard" (DB 51190-93).

[0092] In a preferred embodiment of the present application, a high-organic, high-color and high-salt foam drainage treatment system is provided, and a structure diagram thereof is shown in Figure 1 The system is used to realize the high-organic, high-color and high-salt wastewater treatment method, and the system comprises a flotation unit, a softening coupling coagulation unit, an adsorption coupling coagulation unit, an oxidation unit, an ultrafiltration unit and an evaporation unit connected in sequence.

[0093] The air floatation unit comprises an aeration tank and an air compressor; the upper part of the aeration tank is provided with a scraper; the air compressor is connected to the bottom of the aeration tank through a pipeline and is used for introducing air into the aeration tank; the bottom of the aeration tank is provided with a sludge discharge pipe which is connected to an external filter press and is used for discharging sludge from the bottom of the aeration tank and sending the sludge to the filter press;

[0094] The softening and coupling coagulation unit comprises a first reaction tank, a second reaction tank, a third reaction tank, a fourth reaction tank and a first inclined plate sedimentation tank which are connected in sequence; the middle upper part of the first reaction tank is provided with a liquid inlet for entering the first reaction tank with liquid treated by the air floatation unit; the liquid outlet at the bottom of the first reaction tank is connected to the liquid inlet at the bottom of the second reaction tank; the liquid outlet at the middle upper part of the second reaction tank is connected to the liquid inlet at the middle upper part of the third reaction tank; the liquid outlet at the bottom of the third reaction tank is connected to the liquid inlet at the bottom of the fourth reaction tank; the liquid outlet at the middle part of the fourth reaction tank is connected to the liquid inlet of the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is arranged at the side wall of the first inclined plate sedimentation tank and is lower than (slightly lower than) the position of the inclined plate;

[0095] The first reaction tank, the second reaction tank, the third reaction tank and the fourth reaction tank are provided with stirrers inside for mechanically stirring the liquid therein, and the specific structure and arrangement of the stirrers can adopt conventional techniques in the art, and the present application does not specially limit them;

[0096] The bottom of the first reaction tank, the second reaction tank, the third reaction tank, the fourth reaction tank and the first inclined plate sedimentation tank is provided with a sludge discharge pipe which is connected to an external filter press and is used for discharging sludge from the bottom of the tank and sending the sludge to the filter press;

[0097] The adsorption and coupling coagulation unit comprises a fifth reaction tank, a sixth reaction tank, a seventh reaction tank and a second inclined plate sedimentation tank which are connected in sequence; the bottom of the fifth reaction tank is provided with a liquid inlet for entering the fifth reaction tank with liquid treated by the softening and coupling coagulation unit; the liquid outlet at the middle upper part of the fifth reaction tank is connected to the liquid inlet at the middle upper part of the sixth reaction tank; the liquid outlet at the bottom of the sixth reaction tank is connected to the liquid inlet at the bottom of the seventh reaction tank; the liquid outlet at the middle part of the seventh reaction tank is connected to the liquid inlet of the second inclined plate sedimentation tank, and the liquid inlet of the second inclined plate sedimentation tank is arranged at the side wall of the second inclined plate sedimentation tank and is lower than (slightly lower than) the position of the inclined plate;

[0098] The fifth reaction tank, the sixth reaction tank and the seventh reaction tank are internally provided with agitators for mechanically agitating the liquid therein, the specific structure and arrangement of the agitators can adopt the conventional technology in the field, and the present application does not specially limit them;

[0099] The bottom of the fifth reaction tank, the sixth reaction tank, the seventh reaction tank and the second inclined plate sedimentation tank is provided with a sludge discharge pipe connected with an external filter press for discharging the sludge at the bottom and sending it to the filter press;

[0100] The oxidation unit comprises an oxidation reactor, the inside of which is provided with an immersed ultraviolet lamp and an immersed ultrasonic instrument; the inside of the oxidation reactor is also provided with an agitator for mechanically agitating the liquid therein, the specific structure and arrangement of the agitator can adopt the conventional technology in the field, and the present application does not specially limit them; the side wall of the oxidation reactor is provided with a liquid inlet and a liquid outlet, the liquid inlet can be located at the middle-lower part of the side wall of the oxidation reactor, the liquid outlet can be located at the middle-upper part of the side wall of the oxidation reactor, and the liquid inlet and the liquid outlet are oppositely arranged on the side wall of the oxidation reactor;

[0101] The ultrafiltration unit comprises an ultrafiltration device, which can adopt the conventional ultrafiltration membrane device in the field of wastewater treatment;

[0102] The evaporation unit comprises a steam mechanical re-compression device (MVR).

[0103] It should be noted that, Figure 1 The raw bubble drainage tank is not included in the high-organic-matter, high-colority, high-salt bubble drainage treatment system of the present application. The raw bubble drainage tank is a conventional device in the field.

[0104] It should be noted that the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features indicated or the number of the technical features indicated. For example, the first reaction tank, the second reaction tank and the like reaction tanks described in the present application can all adopt the conventional reaction tank in the field, which can be the same device or different devices, and can be conventionally selected by those skilled in the art. The first inclined plate sedimentation tank and the second inclined plate sedimentation tank described in the present application can both adopt the conventional inclined plate sedimentation tank in the field, which can be the same device or different devices, and can be conventionally selected by those skilled in the art.

[0105] Example 1

[0106] The present embodiment provides a high-organic-matter, high-colority, high-salt bubble drainage treatment method, the flow chart of which is as shown in Figure 1As shown, the method comprises the following steps:

[0107] (1) The foam drainage is made to enter the aeration tank of the air flotation unit, air is introduced into the foam drainage for treatment, the amount of air introduced is 12% to 20% of the water inflow of the foam drainage in the air flotation unit, the hydraulic retention time of the foam drainage in the air flotation unit is 12 to 20 min, then the scum formed on the liquid surface in the aeration tank is scraped off by a scraper (such as a mud scraping plate), a liquid after air flotation treatment is obtained, and the sludge generated after treatment is discharged from the bottom of the aeration tank and sent to the filter press through a pipeline;

[0108] (2) The liquid after air flotation treatment (i.e. supernatant in the aeration tank) is made to enter the first reaction tank of the softening coupled coagulation unit, a first softening agent NaOH is added thereto, and mechanical stirring is carried out at the same time, the speed of mechanical stirring is 250 to 400 r / min, the hydraulic retention time of the liquid after air flotation treatment in the first reaction tank is 8 to 12 min, a liquid after first softening agent treatment is obtained, and the pH value of the liquid after first softening agent treatment is 10 to 11.5; wherein, more specifically, the liquid after air flotation treatment enters the first reaction tank from the liquid inlet at the upper part of the first reaction tank;

[0109] The liquid after first softening agent treatment is further made to enter the second reaction tank from the first reaction tank, a second softening agent Na2CO3 and a barium removal agent Na2SO4 are added thereto, the addition amount of the second softening agent Na2CO3 is 1.7 to 2 times of the total hardness (in terms of CaCO3, mg / L) in the foam drainage, the addition amount of the barium removal agent Na2SO4 is 1.5 to 1.8 times of the barium ion concentration in the foam drainage, mechanical stirring is carried out at the same time, the speed of mechanical stirring is 250 to 400 r / min, the hydraulic retention time of the liquid after first softening agent treatment in the second reaction tank is 8 to 12 min, and a liquid after second softening agent and barium removal agent treatment is obtained; wherein, more specifically, the liquid after first softening agent treatment is discharged from the liquid outlet at the bottom of the first reaction tank and enters the second reaction tank through the liquid inlet at the bottom of the second reaction tank;

[0110] The second softening and barium removal agent treated liquid is then fed from the second reaction tank into a third reaction tank, and a first coagulant, polyaluminum chloride (PAC), is added thereto, the addition amount of the first coagulant being 400-1000 mg / L (i.e. 400-1000 mg of the first coagulant is added per L of the second softening and barium removal agent treated liquid), the polyaluminum chloride (PAC) used having a purity of 100%, and mechanical stirring is carried out at a speed of 250-400 r / min, the hydraulic retention time of the second softening and barium removal agent treated liquid in the third reaction tank being 5-10 min, to obtain a first coagulant treated liquid; more specifically, the second softening and barium removal agent treated liquid is discharged from the liquid outlet at the upper part of the second reaction tank and fed into the third reaction tank through the liquid inlet at the upper part of the third reaction tank;

[0111] The first coagulant treated liquid is then fed from the third reaction tank into a fourth reaction tank, and a first flocculant is added thereto, the first flocculant being anionic polyacrylamide with a molecular weight of 8-12 million, the addition amount of the first flocculant being 1-8 mg / L (i.e. 1-8 mg of the first flocculant is added per L of the first coagulant treated liquid), the anionic polyacrylamide used having a purity of 100%, and mechanical stirring is carried out at a speed of 30-60 r / min, the hydraulic retention time of the first coagulant treated liquid in the fourth reaction tank being 5-10 min, to obtain a first flocculant treated liquid; more specifically, the first coagulant treated liquid is discharged from the liquid outlet at the bottom of the third reaction tank and fed into the fourth reaction tank through the liquid inlet at the bottom of the fourth reaction tank;

[0112] The first flocculant treated liquid is then fed from the fourth reaction tank into a first inclined plate sedimentation tank, and is allowed to settle in the first inclined plate sedimentation tank for 30-40 min, to obtain a softening and coagulation treated liquid; more specifically, the first flocculant treated liquid is discharged from the liquid outlet at the middle part of the fourth reaction tank and fed into the first inclined plate sedimentation tank through the liquid inlet of the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is arranged at the side wall of the first inclined plate sedimentation tank and is slightly lower than the inclined plate;

[0113] The sludge produced in the first reaction tank, the second reaction tank, the third reaction tank, the fourth reaction tank and the first inclined plate sedimentation tank is discharged from the sludge outlet at the bottom of the tank and sent to a filter press through a pipeline;

[0114] (3) the softened and coagulated liquid (i.e. supernatant in the first inclined plate settling tank) is introduced into a fifth reaction tank of the adsorption and coagulation coupled unit, and a first pH regulator, hydrochloric acid and / or sodium hydroxide, is added to adjust the pH of the liquid to 5-6.5, and then an adsorbent is added, which includes a combination of a first group of adsorbents, a second group of adsorbents and a third group of adsorbents; wherein the first group of adsorbents is selected from 1-3 kinds of coconut shell activated carbon, quartz sand and illite, the second group of adsorbents is selected from 1-3 kinds of nutshell activated carbon, resin, bentonite and montmorillonite, and the third group of adsorbents is selected from 1 kind of coal and activated alumina, and the dosage of a single adsorbent is 5-100 g / L (i.e. the dosage of each adsorbent in the softened and coagulated liquid is 5-100 g per L), and then mechanical stirring is performed at a speed of 250-400 r / min, and the hydraulic retention time of the softened and coagulated liquid in the fifth reaction tank is 30-40 min to obtain an adsorbent-treated liquid; more specifically, the softened and coagulated liquid is discharged from the liquid outlet of the first inclined plate settling tank and introduced into the fifth reaction tank through the liquid inlet at the bottom of the fifth reaction tank;

[0115] Then the adsorbent-treated liquid is introduced into a sixth reaction tank, and a second coagulant, polyaluminum chloride (PAC), is added, and the dosage of the second coagulant is 400-1000 mg / L (i.e. 400-1000 mg of the second coagulant is added per L of the adsorbent-treated liquid), and the purity of the polyaluminum chloride (PAC) used is 100%, and mechanical stirring is performed at a speed of 250-400 r / min, and the hydraulic retention time of the adsorbent-treated liquid in the sixth reaction tank is 5-10 min to obtain a second coagulant-treated liquid; more specifically, the adsorbent-treated liquid is discharged from the liquid outlet at the upper part of the fifth reaction tank and introduced into the sixth reaction tank through the liquid inlet at the upper part of the sixth reaction tank;

[0116] The second coagulant treated liquid is then fed into the seventh reaction tank, and a second flocculant is added into the seventh reaction tank. The second flocculant is cationic polyacrylamide with a cationic degree of 30-60 and a molecular weight of 3-8 million. The addition amount of the second flocculant is 1-10 mg / L (i.e. 1-10 mg of the second flocculant is added per L of the second coagulant treated liquid). The purity of the cationic polyacrylamide used is 100%. Meanwhile, mechanical stirring is performed. The speed of the mechanical stirring is 30-60 r / min. The hydraulic retention time of the second coagulant treated liquid in the seventh reaction tank is 5-10 min. A second flocculant treated liquid is obtained. More specifically, the second coagulant treated liquid is discharged from the liquid outlet at the bottom of the sixth reaction tank and fed into the seventh reaction tank through the liquid inlet at the bottom of the seventh reaction tank.

[0117] Subsequently, the second flocculant treated liquid is fed from the seventh reaction tank into the second inclined plate sedimentation tank, and is allowed to stay in the second inclined plate sedimentation tank for 30-40 min for sedimentation. A flocculation and coagulation treated liquid is obtained. More specifically, the second flocculant treated liquid is discharged from the liquid outlet in the middle of the seventh reaction tank and fed into the second inclined plate sedimentation tank through the liquid inlet of the second inclined plate sedimentation tank. The liquid inlet of the second inclined plate sedimentation tank is arranged on the side wall of the second inclined plate sedimentation tank and is slightly lower than the inclined plate.

[0118] The sludge produced in the fifth reaction tank, the sixth reaction tank, the seventh reaction tank and the second inclined plate sedimentation tank is discharged from the sludge outlet at the bottom of the tank and sent to the filter press through the pipeline.

[0119] (4) The flocculation and coagulation treated liquid (i.e. the supernatant in the second inclined plate sedimentation tank) is fed into the oxidation reactor in the oxidation unit, and a second pH adjuster, hydrochloric acid and / or sodium hydroxide, is added into the oxidation reactor to adjust the pH value of the liquid to 5-6. Then, a first oxidant, Na2S2O8, and a second oxidant, H2O2, are sequentially added into the oxidation reactor. The molar ratio of the addition amount of the first oxidant to the second oxidant is (1-4): 1. The ratio of the addition amount of the second oxidant to the COD concentration of the treated bubble drainage is (0.6-2): 1. The flocculation and coagulation treated liquid stays in the oxidation reactor for 30-60 min. Oxidation treatment is performed under the action of ultraviolet and ultrasonic waves and mechanical stirring in the oxidation reactor. The frequency of the ultrasonic wave in the oxidation reactor is 20-28 kHz. The power of the ultrasonic wave is 50-250 W. The wavelength of the ultraviolet is 185-400 nm. The power of the ultraviolet is 3-55 W. The ultraviolet and the ultrasonic wave in the oxidation reactor are generated by the immersed ultraviolet lamp and the immersed ultrasonic instrument arranged in the oxidation reactor, respectively. The speed of the mechanical stirring is 30-60 r / min. An oxidation treated liquid is obtained.

[0120] (5) The oxidized liquid is introduced into an ultrafiltration device of an ultrafiltration unit, the ultrafiltration device can adopt a conventional ultrafiltration membrane device in the field of wastewater treatment, and a third pH adjuster hydrochloric acid and / or sodium hydroxide is added in the ultrafiltration device to adjust the pH value of the liquid to neutral, to obtain an ultrafiltration treated liquid; more specifically, the oxidized liquid is discharged from the liquid outlet at the upper part of the oxidation reactor and enters the ultrafiltration device through the liquid inlet of the ultrafiltration device;

[0121] (6) The ultrafiltration treated liquid is introduced into an evaporation unit, and evaporation is carried out in a steam mechanical re-compression device (MVR), and the obtained condensate is discharged up to standard; more specifically, the condensate reaches the first level standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the first level standard of the "Sichuan Province Water Pollutant Discharge Standard" (DB 51190-93).

[0122] This example is to treat the foam drainage of a shale gas well in South Sichuan, and the indicators of the foam drainage and the indicators of the condensate (i.e. the effluent) after treatment in this example are shown in Table 1.

[0123] Comparative Example 1

[0124] This comparative example provides a conventional treatment method (softening-coagulation-membrane treatment-evaporation) for foam drainage, which comprises the following steps:

[0125] (1) The foam drainage is introduced into a reaction tank of a softening unit, and a softening agent Ca(OH)2 is added thereto, and mechanical stirring is carried out at the same time, the speed of the mechanical stirring is 250-400 r / min, the hydraulic retention time of the foam drainage in the reaction tank is 8-12 min, to obtain a softening treated liquid, and the pH value of the softening treated liquid is 9.5-11.5;

[0126] (2) The softening treated liquid is introduced into a reaction tank of a coagulation unit, and a coagulant polyaluminum chloride (PAC) is added thereto, the dosage of the coagulant is 400-1000 mg / L, the purity of the polyaluminum chloride (PAC) used is 100%, and mechanical stirring is carried out at the same time, the speed of the mechanical stirring is 250-400 r / min, the hydraulic retention time of the softening treated liquid in the reaction tank is 5-10 min, to obtain a coagulation treated liquid;

[0127] (3) The coagulation treated liquid is introduced into an ultrafiltration device of an ultrafiltration unit, the ultrafiltration device can adopt a conventional ultrafiltration membrane device in the field of wastewater treatment, and a pH adjuster hydrochloric acid and / or sodium hydroxide is added in the ultrafiltration device to adjust the pH value of the liquid to neutral, to obtain an ultrafiltration treated liquid;

[0128] (4) The liquid after the ultrafiltration treatment is introduced into an evaporation unit, and evaporated in a steam mechanical recompression device (MVR) to obtain condensed liquid (i.e. effluent water).

[0129] The treatment object of the present comparative example is the same as that of Example 1, and the indicators of the condensed liquid (i.e. effluent water) after the treatment of the present comparative example are shown in Table 1.

[0130] Table 1 Comparison of effluent water quality between bubble drainage and Example 1 and Comparative Example 1

[0131]

[0132] The water quality analysis results in Table 1 show that the COD, ammonia nitrogen, barium, color, petroleum, chlorides and suspended solids in the bubble drainage far exceed the first level standards of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the "Sichuan Province Water Pollutant Discharge Standard" (DB 51190-93). The COD and ammonia nitrogen in the effluent water after the treatment by the conventional method of Comparative Example 1 obviously exceed the two standards, while the COD, ammonia nitrogen, barium, color, petroleum, chlorides and suspended solids in the effluent water after the treatment by the method of Example 1 of the present application are far lower than the two standards.

Claims

1. A method for treating wastewater with high organic matter content, high color, and high salinity, comprising the following steps: (1) The wastewater is subjected to air flotation treatment to obtain the air flotation treated liquid; (2) The liquid after the air flotation treatment is introduced into the softening coupled coagulation unit. In the softening coupled coagulation unit, the liquid after the air flotation treatment is first treated with a first softening agent, then treated with a second softening agent and a barium removal agent, then treated with a first coagulant, then treated with a first flocculant, and then after sedimentation, the liquid after the softening coupled coagulation treatment is obtained. (3) The liquid after softening and coupling coagulation treatment is introduced into the adsorption and coupling coagulation unit. In the adsorption and coupling coagulation unit, the liquid after softening and coupling coagulation treatment is adjusted to pH value by a first pH adjuster, then treated with an adsorbent, then treated with a second coagulant, then treated with a second flocculant, and then after sedimentation, the liquid after adsorption and coupling coagulation treatment is obtained. (4) The liquid after adsorption-coupling coagulation treatment is introduced into the oxidation reactor in the oxidation unit, and a second pH adjuster is added to adjust the pH value of the liquid to 5-6. Then, the first oxidant and the second oxidant are added in sequence. The liquid after adsorption-coupling coagulation treatment stays in the oxidation reactor for a period of time and is oxidized under the action of ultraviolet light and ultrasound in the oxidation reactor to obtain the oxidized liquid. (5) The oxidized liquid is subjected to ultrafiltration to obtain an ultrafiltration liquid; (6) The liquid after ultrafiltration is evaporated and the resulting condensate is discharged in compliance with standards.

2. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, The wastewater is a foaming wastewater.

3. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, Step (1) specifically includes: allowing wastewater to enter the air flotation unit, introducing air into the wastewater to treat it, scraping off the scum formed on the surface of the liquid, and obtaining the liquid after air flotation treatment.

4. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 3, wherein, In step (1), the device for treating wastewater in the flotation unit includes an aeration tank.

5. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 3, wherein, In step (1), the amount of air introduced into the wastewater is 5% to 20% of the wastewater in the flotation unit, and the hydraulic residence time of the wastewater in the flotation unit is 5 to 20 minutes.

6. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 3, wherein, Step (1) further includes sending the sludge produced after treatment to a filter press.

7. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 6, wherein, Step (1) further includes: discharging the treated sludge from the bottom of the aeration tank and sending it to the filter press via pipeline.

8. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (2), the treatment with the first softener includes: allowing the liquid after air flotation treatment to enter the first reaction tank, adding the first softener to it, and simultaneously performing mechanical stirring. The liquid after air flotation treatment stays in the first reaction tank for a period of time to obtain the liquid treated with the first softener. The speed of mechanical stirring is 100~400r / min.

9. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 8, wherein, In step (2), the hydraulic residence time of the liquid after air flotation treatment in the first reaction tank is 8~12 minutes.

10. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (2), the first softening agent includes NaOH; And / or, in step (2), the pH value of the liquid treated with the first softener is 9.5~11.

5.

11. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 8, wherein, In step (2), the treatment with the second softener and the barium remover includes: allowing the liquid treated with the first softener to enter the second reaction tank from the first reaction tank, and adding the second softener and the barium remover to it, while mechanically stirring. The liquid treated with the first softener stays in the second reaction tank for a period of time to obtain the liquid treated with the second softener and the barium remover. The mechanical stirring speed is 100~400r / min.

12. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 11, wherein, In step (2), the hydraulic residence time of the liquid treated with the first softener in the second reaction tank is 8 to 12 minutes.

13. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (2), the second softening agent includes Na2CO3, and the barium removal agent includes Na2SO4; And / or, in step (2), the dosage of the second softener is 1.5 to 2 times the total hardness of the wastewater, and the dosage of the barium removal agent is 1.5 to 2 times the barium ion concentration in the wastewater.

14. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 11, wherein, In step (2), the treatment with the first coagulant includes: allowing the liquid treated with the second softener and the barium remover to enter the third reaction tank from the second reaction tank, and adding the first coagulant to it while mechanically stirring. The liquid treated with the second softener and the barium remover stays in the third reaction tank for a period of time to obtain the liquid treated with the first coagulant. The mechanical stirring speed is 100~400r / min.

15. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 14, wherein, In step (2), the hydraulic residence time of the liquid treated with the second softener and the barium removal agent in the third reaction tank is 5 to 10 minutes.

16. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (2), the first coagulant includes polyaluminum chloride; And / or, in step (2), the dosage of the first coagulant is 50~1000 mg / L.

17. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 14, wherein, In step (2), the treatment with the first flocculant includes: allowing the liquid treated with the first coagulant to enter the fourth reaction tank from the third reaction tank, adding the first flocculant to it, and simultaneously performing mechanical stirring. The liquid treated with the first coagulant stays in the fourth reaction tank for a period of time to obtain the liquid treated with the first flocculant. The mechanical stirring speed is 20~80r / min.

18. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 17, wherein, In step (2), the hydraulic residence time of the liquid treated with the first coagulant in the fourth reaction tank is 5 to 10 minutes.

19. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (2), the first flocculant includes polyacrylamide; And / or, in step (2), the first flocculant includes anionic polyacrylamide with a molecular weight of 8 million to 15 million; And / or, in step (2), the dosage of the first flocculant is 0.05~10 mg / L.

20. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 17, wherein, In step (2), obtaining the softened coupled coagulation treated liquid after sedimentation includes: allowing the liquid treated with the first flocculant to enter the first inclined plate sedimentation tank from the fourth reaction tank, and letting it stay in the first inclined plate sedimentation tank for a period of time to settle, thereby obtaining the softened coupled coagulation treated liquid.

21. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 20, wherein, In step (2), the liquid treated with the first flocculant stays in the first inclined plate sedimentation tank for 20 to 40 minutes.

22. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 20, wherein, Step (2) further includes sending the sludge generated in the first reaction tank, and / or the second reaction tank, and / or the third reaction tank, and / or the fourth reaction tank, and / or the first inclined plate sedimentation tank to a filter press.

23. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (3), the process of adjusting the pH value of the liquid after softening and coagulation treatment with a first pH adjuster and then treating it with an adsorbent includes: allowing the liquid after softening and coagulation treatment to enter the fifth reaction tank, adding the first pH adjuster to adjust the pH value of the liquid to 5~6.5, adding the adsorbent, and then mechanically stirring. The liquid after softening and coagulation treatment stays in the fifth reaction tank for a period of time to obtain the liquid treated with the adsorbent. The mechanical stirring speed is 100~400 r / min.

24. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 23, wherein, In step (3), the hydraulic residence time of the softened and coupled coagulated liquid in the fifth reaction tank is 20-40 min.

25. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (3), the first pH adjuster includes hydrochloric acid and / or sodium hydroxide; And / or, in step (3), the adsorbent comprises a combination of 3 to 7 of the following: coconut shell activated carbon, fruit shell activated carbon, coal, quartz sand, resin, bentonite, illite, activated alumina and montmorillonite; And / or, in step (3), the adsorbent includes a combination of a first group of adsorbents, a second group of adsorbents and a third group of adsorbents; wherein, the first group of adsorbents is selected from 1 to 3 of coconut shell activated carbon, quartz sand and illite, the second group of adsorbents is selected from 1 to 3 of fruit shell activated carbon, resin, bentonite and montmorillonite, and the third group of adsorbents is selected from 1 of coal and activated alumina; the dosage of a single adsorbent is 5 to 100 g / L.

26. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 23, wherein, In step (3), the treatment with the second coagulant includes: allowing the liquid treated by the adsorbent to enter the sixth reaction tank, adding the second coagulant to it, and simultaneously performing mechanical stirring. The liquid treated by the adsorbent stays in the sixth reaction tank for a period of time to obtain the liquid treated by the second coagulant. The mechanical stirring speed is 100~400r / min.

27. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 26, wherein, In step (3), the hydraulic residence time of the liquid treated with the adsorbent in the sixth reaction tank is 5 to 10 minutes.

28. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (3), the second coagulant includes polyaluminum chloride; And / or, in step (3), the dosage of the second coagulant is 50~1000 mg / L.

29. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 26, wherein, In step (3), the treatment with the second flocculant includes: the liquid treated with the second coagulant is introduced into the seventh reaction tank, and the second flocculant is added to it while mechanical stirring is performed. The liquid treated with the second coagulant stays in the seventh reaction tank for a period of time to obtain the liquid treated with the second flocculant. The mechanical stirring speed is 20~80r / min.

30. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 29, wherein, In step (3), the hydraulic residence time of the liquid treated with the second coagulant in the seventh reaction tank is 5 to 10 minutes.

31. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (3), the second flocculant includes polyacrylamide; And / or, in step (3), the second flocculant comprises cationic polyacrylamide with a cationicity of 10 to 60 and a molecular weight of 3 million to 8 million; And / or, in step (3), the dosage of the second flocculant is 0.05~10 mg / L.

32. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 29, wherein, In step (3), obtaining the liquid after adsorption-coupled coagulation treatment after sedimentation includes: allowing the liquid treated with the second flocculant to enter the second inclined plate sedimentation tank from the seventh reaction tank, and letting it stay in the second inclined plate sedimentation tank for a period of time to settle, thereby obtaining the liquid after adsorption-coupled coagulation treatment.

33. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 32, wherein, In step (3), the liquid treated with the second flocculant stays in the second inclined plate sedimentation tank for 20 to 40 minutes.

34. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 32, wherein, Step (3) further includes sending the sludge generated in the fifth reaction tank, and / or the sixth reaction tank, and / or the seventh reaction tank, and / or the second inclined plate sedimentation tank to a filter press.

35. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (4), the second pH adjuster includes hydrochloric acid and / or sodium hydroxide.

36. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (4), the first oxidant includes Na2S2O8, and the second oxidant includes H2O2; And / or, in step (4), the molar ratio of the first oxidant to the second oxidant is (1~4):1, and the ratio of the amount of the second oxidant added to the COD concentration of the treated wastewater is (0.6~2):

1.

37. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, In step (4), the frequency of the ultrasound in the oxidation reactor is 20~28kHz and the power is 50~250W; the wavelength of the ultraviolet light in the oxidation reactor is 185~400nm and the power is 3~55W. And / or, in step (4), the oxidation treatment is carried out under mechanical stirring at a speed of 30~80 r / min; And / or, in step (4), the liquid after the adsorption-coupled coagulation treatment stays in the oxidation reactor for 20 to 60 minutes.

38. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, Step (5) specifically includes: allowing the oxidized liquid to enter the ultrafiltration device of the ultrafiltration unit, and adding a third pH adjuster to the ultrafiltration device to adjust the pH value of the liquid to neutral, thereby obtaining the ultrafiltration-treated liquid.

39. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 38, wherein, In step (5), the third pH adjuster includes hydrochloric acid and / or sodium hydroxide.

40. The method for treating wastewater with high organic matter, high color, and high salinity according to claim 1, wherein, Step (6) specifically includes: allowing the ultrafiltration treated liquid to enter the evaporation unit, evaporating it in the steam mechanical recompression device, and discharging the condensate that meets the standards.

41. A wastewater treatment system for high organic matter, high color, and high salinity, the system being used to implement the wastewater treatment method for high organic matter, high color, and high salinity as described in any one of claims 1-40, the system comprising a flotation unit, a softening coupled coagulation unit, an adsorption coupled coagulation unit, an oxidation unit, an ultrafiltration unit, and an evaporation unit connected in sequence; the oxidation unit comprising an oxidation reactor, the oxidation reactor being internally equipped with an immersion ultraviolet lamp and an immersion ultrasonic instrument.

42. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The air flotation unit includes an aeration tank.

43. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 42, wherein, The aeration tank is equipped with a scraper at the top.

44. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 42, wherein, The air flotation unit also includes an air compressor, which is connected to the bottom of the aeration tank via a pipeline for introducing air into the aeration tank.

45. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 42, wherein, The bottom of the aeration tank is equipped with a sludge discharge pipe, which is connected to an external filter press to discharge sludge from the bottom of the aeration tank and send it to the filter press.

46. ​​The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The softening coupled coagulation unit includes a first reaction tank, a second reaction tank, a third reaction tank, a fourth reaction tank, and a first inclined plate sedimentation tank connected in sequence. A liquid inlet is provided in the upper middle part of the first reaction tank to allow liquid treated by the air flotation unit to enter the first reaction tank. A liquid outlet at the bottom of the first reaction tank is connected to a liquid inlet at the bottom of the second reaction tank. A liquid outlet in the upper middle part of the second reaction tank is connected to a liquid inlet in the upper middle part of the third reaction tank. A liquid outlet at the bottom of the third reaction tank is connected to a liquid inlet at the bottom of the fourth reaction tank. A liquid outlet in the middle of the fourth reaction tank is connected to a liquid inlet in the first inclined plate sedimentation tank, and the liquid inlet of the first inclined plate sedimentation tank is located on the side wall of the first inclined plate sedimentation tank and below the inclined plate. The first reaction tank, the second reaction tank, the third reaction tank, and the fourth reaction tank are equipped with stirrers for mechanically stirring the liquids therein.

47. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 46, wherein, The bottom of the first reaction tank, and / or the second reaction tank, and / or the third reaction tank, and / or the fourth reaction tank, and / or the first inclined plate sedimentation tank is provided with a sludge discharge pipe, which is connected to an external filter press for discharging sludge from the bottom of the tank and sending it to the filter press.

48. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The adsorption-coupled coagulation unit includes a fifth reaction tank, a sixth reaction tank, a seventh reaction tank, and a second inclined plate sedimentation tank connected in sequence. The bottom of the fifth reaction tank has a liquid inlet for allowing liquid from the softening-coupled coagulation unit to enter the fifth reaction tank after softening-coupled coagulation treatment. The upper liquid outlet of the fifth reaction tank is connected to the upper liquid inlet of the sixth reaction tank. The bottom liquid outlet of the sixth reaction tank is connected to the bottom liquid inlet of the seventh reaction tank. The middle liquid outlet of the seventh reaction tank is connected to the liquid inlet of the second inclined plate sedimentation tank, and the liquid inlet of the second inclined plate sedimentation tank is located on the side wall of the second inclined plate sedimentation tank and below the inclined plate. The fifth, sixth, and seventh reaction tanks are equipped with stirrers for mechanically stirring the liquids therein.

49. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 48, wherein, The bottom of the fifth reaction tank, and / or the sixth reaction tank, and / or the seventh reaction tank, and / or the second inclined plate sedimentation tank is provided with a sludge discharge pipe, which is connected to an external filter press for discharging sludge from the bottom of the tank and sending it to the filter press.

50. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The oxidation reactor is also equipped with a stirrer for mechanically stirring the liquid inside.

51. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The ultrafiltration unit includes an ultrafiltration device.

52. The wastewater treatment system for high organic matter, high color, and high salinity according to claim 41, wherein, The evaporation unit includes a steam mechanical recompression device.

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