CN115340225A - Wastewater treatment method and application thereof - Google Patents
Wastewater treatment method and application thereof Download PDFInfo
- Publication number
- CN115340225A CN115340225A CN202110522883.2A CN202110522883A CN115340225A CN 115340225 A CN115340225 A CN 115340225A CN 202110522883 A CN202110522883 A CN 202110522883A CN 115340225 A CN115340225 A CN 115340225A
- Authority
- CN
- China
- Prior art keywords
- water
- wastewater
- reverse osmosis
- nanofiltration
- scale inhibitor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
- C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
- C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/02—Softening water by precipitation of the hardness
- C02F5/06—Softening water by precipitation of the hardness using calcium compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
- C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
- C02F5/14—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances containing phosphorus
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
The invention provides a wastewater treatment method, which comprises the step of carrying out first contact on wastewater containing a scale inhibitor and ozone gas to reduce the content of the scale inhibitor in the wastewater. By adopting the ozone oxidation treatment of the wastewater containing the scale inhibitor, the scale-forming salts such as calcium sulfate and calcium carbonate in the membrane concentrated water can be separated out, the wastewater recovery rate is improved, and the long-period effective operation of a wastewater treatment unit is ensured. The process flow is simple and convenient to operate, no by-product is generated, the storage and sale of miscellaneous salt or waste water are not required to be considered, and compared with the prior art, the process flow has social and economic benefits.
Description
Technical Field
The invention relates to a wastewater treatment method and application thereof.
Background
Zero discharge is a water using mode with high water saving level of a power plant, and has good social and environmental benefits. With the rapid development of economy and electric power in China, in northern areas with more coal and less water, the available amount of water resources is increasingly reduced, the water price and the pollution discharge cost are continuously increased, and the zero discharge of the waste water of the power plant is inevitable. The membrane concentration and salt separation technology is widely applied to the zero-emission process. The recycling treatment of the concentrated solution becomes a link of the zero emission process, and the trend of finding a treatment method with low cost and high efficiency for recycling is formed.
The domestic invention patent CN 201610982209.1 discloses a low-cost power plant desulfurization wastewater zero-discharge treatment process, which mainly comprises pretreatment, membrane concentration and evaporative crystallization processes. In the pretreatment process, lime is used for magnesium removal reaction in primary softening, sodium sulfate is added in secondary softening to enable supersaturated crystallization and separation of calcium sulfate solution at normal temperature, so that partial calcium hardness softening is realized, secondary softened effluent enters an NF unit for salt separation, NF concentrated water and primary softened effluent are mixed and enter a crystallizer, and divalent salt calcium sulfate is separated out; and (3) allowing NF produced water to enter an RO system to realize water production recycling, allowing concentrated water to enter an evaporator to be evaporated and crystallized, and performing crystallization and separation on crystal slurry.
The invention of domestic patent CN108178408A discloses a device and a method for treating desulfurization waste water, which comprises the following steps: firstly, the desulfurization wastewater enters a pretreatment system for pretreatment in an early stage, wherein the pretreatment system comprises a tempering tank, a lime magnesium-conditioning system and a filtering system; the effluent of the filtration system enters a nanofiltration system for salt separation, the concentrated water of the nanofiltration system returns to a tempering tank for treatment, and the fresh water of the nanofiltration system enters a seawater reverse osmosis system; fresh water of the seawater reverse osmosis system and fresh water of the brackish water reverse osmosis system enter the nanofiltration system, and the rest fresh water is recycled; concentrated water of the seawater reverse osmosis system and concentrated water of the brackish water reverse osmosis system enter an electrically driven membrane separation system, fresh water of the electrically driven membrane separation system returns to the brackish water reverse osmosis system, and concentrated water of the electrically driven membrane separation system enters an evaporative crystallization system.
The domestic invention patent CN 200310108454.2 discloses an electro-Fenton oxidation method of scale inhibitor in reverse osmosis concentrated solution, in the technical scheme of the invention, the reverse osmosis concentrated solution is treated by adopting the electro-Fenton method, and divalent iron ions (Fe) generated in the electrochemical process are utilized 2+ ) With hydrogen peroxide (H) 2 O 2 ) Strong oxidant-hydroxyl radical (OH) generated by reaction is used for oxidizing and destroying the scale inhibitor in the reverse osmosis concentrated solution to destabilize the high supersaturation scale-forming ions in the solution, and then the solution is coagulated to make the scale-forming salts in the concentrated solution such as CaCO 3 And the scaling tendency of the solution is reduced by precipitation, so that the concentrated solution can be reused as inlet water, and the water recovery rate of the reverse osmosis system is improved.
The domestic invention patent CN 200610116306.9 discloses a method for coagulating and removing calcium sulfate scaling salt in reverse osmosis concentrated solution, which utilizes coagulant to remove Ca in the reverse osmosis concentrated solution 2+ 、SO 4 2- The coagulation effect of the nanometer particles formed by the scaling ions enables the scaling ions with high supersaturation degree in the solution to be deposited out, then the sediment is removed through solution filtration, and the scaling trend of the reverse osmosis concentrated solution is reduced, so that the reverse osmosis concentrated solution can be reused as inlet water, and the water recovery rate of a reverse osmosis system is improved.
Aiming at the water quality characteristics of the desulfurization wastewater, the zero-discharge treatment technology is generally integrated and combined by two or more technologies such as pretreatment, salt separation, membrane concentration, evaporative crystallization and the like, and the technologies are all related in the domestic invention patents. And (5) finding by comparison. The concentration degree and the reduction degree are different in the subsequent membrane treatment process, and the zero emission treatment is limited to a certain extent. The concentrated solution has large directly evaporated water amount and high cost; the use of fenton oxidation in the concentrate does not allow the recovery of divalent salts and also produces a certain amount of sludge. If the concentrated solution is not treated and directly enters the softening unit, the risk that the crystallization process cannot be stably carried out due to the accumulation of the scale inhibitor exists.
Disclosure of Invention
In view of the above situation, the invention provides an ozone oxidation treatment method of a scale inhibitor in industrial wastewater, which can reduce the scaling tendency of a membrane concentrated solution and reuse the membrane concentrated solution as inlet water. The technical scheme of the invention utilizes O in the ozone oxidation process 3 Oxidizing and destroying the scale inhibitor in the membrane-falling concentrated solution by itself or generated hydroxyl free radical (OH), destabilizing high supersaturation scaling ions in the solution, and coagulating the solution to make the scaling salts in the concentrated solution such as CaSO 4 、CaCO 3 And the precipitation is carried out to reduce the scaling tendency of the solution, so that the concentrated solution can be reused as inlet water, and the water recovery rate of a membrane concentration system is improved. And the ozone oxidation has no sludge or other byproducts, and has no influence on the water quality.
The invention can control different kinds of antisludging agents aiming at water quality with different supersaturation degrees. The introduction of ozone oxidation provides important guarantee for the stable operation of a subsequent membrane system, improves the water recovery rate of the system, reduces the discharge of concentrated solution, and simultaneously can recover divalent salt such as calcium sulfate and the like from the membrane concentrated solution, thereby having important economic value and social significance.
In a first aspect, the present invention provides a method for treating wastewater, comprising first contacting wastewater containing a scale inhibitor with ozone gas to reduce the content of the scale inhibitor in the wastewater.
According to some embodiments of the invention, the scale inhibitor comprises a polycarboxylic acid molecule and/or an organic phosphonic acid molecule.
According to some embodiments of the invention, the wastewater comprises concentrate water after membrane concentration.
According to a preferred embodiment of the invention, the wastewater comprises water selected from reverse osmosis concentrate and/or nanofiltration concentrate.
According to some embodiments of the invention, the pH of the wastewater is between 6 and 10, e.g. 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5.
According to a preferred embodiment of the invention, the pH of the waste water is between 8 and 10.
According to some embodiments of the invention, the concentration of the scale inhibitor in the wastewater is 5-100ppm, such as 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm.
According to some embodiments of the invention, the ozone gas is added in a concentration of 20-150mg/L, such as 30mg/L, 50mg/L, 70mg/L, 90mg/L, 110mg/L, 130mg/L. In the invention, the dosage of the ozone gas refers to the ozone gas added into each liter of wastewater.
According to a preferred embodiment of the present invention, the ozone gas is added in a concentration of 50-140mg/L.
According to some embodiments of the invention, the time of the first contacting is 10-40min.
According to a preferred embodiment of the invention, the first contact time is 20-40min.
According to some embodiments of the invention, the ozone gas is produced by an ozone generator.
According to some embodiments of the invention, the ozone gas is passed into the wastewater through an aeration disc or an eductor.
According to some embodiments of the invention, the method further comprises second contacting the wastewater after the first contacting with a flocculant to obtain a precipitate and a wastewater of reduced hardness.
According to some preferred embodiments of the invention, the wastewater with reduced hardness is recycled.
According to some embodiments of the invention, the flocculant comprises at least one selected from the group consisting of polyacrylamide, polyaluminium sulfate and polyferric sulfate.
According to some embodiments of the invention, the flocculant is added in an amount of 2 to 10mg/L.
According to some embodiments of the invention, the time of the second contacting is 10-40min.
According to some preferred embodiments of the invention, the time of the second contacting is 20-40min.
According to some embodiments of the invention, the temperature of the second contacting is 10-40 ℃.
According to a preferred embodiment of the invention, the supersaturation of scaling salts in the hardness-reduced wastewater is reduced to 100% to 230%, such as 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%.
According to a preferred embodiment of the invention, supersaturation of scaling salts in the hardness-reduced wastewater is reduced to 100% to 150%.
According to a further preferred embodiment of the invention, the supersaturation of scaling salts in said hardness-reduced wastewater is reduced to 115% to 125%.
In the present invention, the supersaturation of scaling salts =100% (-molarity of the scaling salts in the salt solution/solubility corrected for by the homoionic effect (i.e. saturation concentration of scaling salts)).
According to some embodiments of the invention, the scale forming salts comprise calcium sulfate and/or calcium carbonate.
According to the invention, after the ozone treatment, the content of other COD in the wastewater is reduced, the purity of the calcium sulfate as the byproduct of divalent salt is improved, and the resource value of the calcium sulfate is directly influenced. The reverse osmosis concentrated solution without scale forming ions and scale inhibitor can be reused as reverse osmosis inlet water, and the water recovery rate of a reverse osmosis system is improved by 7 percent.
In a second aspect, the present invention provides the use of a method according to the first aspect in a method of treating desulphurised waste water.
According to some embodiments of the invention, the desulfurized wastewater comprises a scale inhibitor.
According to a preferred embodiment of the present invention, the concentration of the scale inhibitor is 5 to 100ppm.
According to some embodiments of the invention, the method for treating desulfurization waste water comprises the steps of:
step A: contacting the desulfurization wastewater with a calcium hydroxide solution for softening pretreatment to obtain a solid precipitate and softened desulfurization wastewater;
and B: contacting the softened desulfurization wastewater with a scale inhibitor, and performing nanofiltration treatment to obtain nanofiltration concentrated water and nanofiltration produced water;
step C: b, enabling the nanofiltration concentrated water obtained in the step B to contact with ozone gas, and carrying out ozone treatment to obtain nanofiltration concentrated water after ozone treatment;
step D: optionally contacting the nanofiltration concentrated water treated by ozone with a flocculating agent to crystallize and separate out solids and generate crystallized water;
step E: and C, performing reverse osmosis treatment on the nanofiltration water produced in the step B to obtain reverse osmosis concentrated water and reverse osmosis water.
According to some embodiments of the invention, the method further comprises step F: and performing bipolar membrane electrodialysis treatment on the reverse osmosis concentrated water to obtain a sodium hydroxide solution, a hydrochloric acid solution and electrodialysis produced water, wherein the sodium hydroxide solution and the hydrochloric acid solution are returned to the softening pretreatment for recycling.
According to some embodiments of the invention, the water produced by crystallization is recycled by refluxing into nanofiltration influent water.
According to some embodiments of the invention, the reverse osmosis produced water is recycled as reuse water.
According to some embodiments of the invention, the electrodialysis product water is recycled to the reverse osmosis treatment.
According to some embodiments of the invention, in step a, the softening pretreatment comprises a first softening pretreatment and a second softening pretreatment; wherein the first softening pretreatment comprises the steps of contacting the desulfurization wastewater with a calcium hydroxide solution, organic sulfur, a flocculating agent and a coagulant aid, and neutralizing, settling, flocculating and clarifying to obtain clarified water.
According to some embodiments of the invention, in step a, the second softening pretreatment comprises contacting the clarified effluent with a calcium hydroxide solution to obtain a magnesium hydroxide precipitate and softened desulfurization wastewater.
According to some embodiments of the invention, in the first softening treatment, the pH of the desulfurization waste water is 9 to 10.
According to a preferred embodiment of the present invention, in the step a, the pH of the desulfurization waste water in the first softening treatment is 9 to 9.5.
According to some embodiments of the invention, in step a, the pH of the clarified effluent of the second softening pretreatment is between 11 and 12.
According to a preferred embodiment of the present invention, in step a, the pH of the clarified effluent in the second softening pretreatment is from 11.5 to 12.
According to some embodiments of the invention, in step a, the solid precipitate comprises magnesium hydroxide.
According to some embodiments of the invention, in step B, the pH of the softened sweet wastewater is from 6 to 8.
According to a preferred embodiment of the present invention, in step B, the pH of the softened desulfurization waste water is 6.5 to 7.5.
According to some embodiments of the invention, in step B, the scale inhibitor comprises a polycarboxylic acid molecule and/or an organic phosphonic acid molecule.
According to some embodiments of the invention, in step C, the pH of the nanofiltration concentrate water of the reaction is between 8 and 10.
According to some embodiments of the invention, the ozone gas is added in a concentration of 20-150mg/L. In the invention, the dosage of the ozone gas refers to the ozone gas added in each liter of wastewater. .
According to a preferred embodiment of the present invention, the ozone gas is added in a concentration of 50-140mg/L.
According to some embodiments of the invention, the time of the first contacting is 10-40min.
According to a preferred embodiment of the invention, the first contact time is 20-40min.
According to some embodiments of the invention, in step C, the ozone gas is produced by an ozone generator.
According to some embodiments of the invention, in step C, the ozone gas is passed into the wastewater containing the scale inhibitor through an aeration disc or an eductor.
According to some embodiments of the invention, in step C, the ozone gas is mixed with the scale inhibitor-containing wastewater by a gas-liquid mixing pump.
According to some embodiments of the invention, in step D, the solids comprise calcium sulfate.
In the invention, the desulfurization wastewater is neutralized by calcium hydroxide to remove heavy metal ions and most suspended matters, and the pH is adjusted to be more than 11 to remove magnesium ions; the effluent enters a nanofiltration salt separation system after passing through an ultrafiltration system, and nanofiltration concentrated water rich in divalent salt is firstly oxidized by ozone to destroy the scale inhibition effect of the scale inhibitor. In the process of softening and calcium hardness removal by pretreatment, sodium carbonate is replaced by sodium sulfate, most of calcium hardness is regulated and controlled, the crystallization technology and the nanofiltration technology are combined, the softening cost is reduced, and a divalent salt calcium sulfate byproduct is obtained. The crystallized effluent returns to a nanofiltration unit for circular treatment. And (3) the nanofiltration produced water rich in monovalent salt enters a reverse osmosis system for concentration and decrement, the reverse osmosis produced water reaches the reuse standard and returns to a plant area for reuse, the reverse osmosis concentrated water enters a bipolar membrane electrodialysis section, and monovalent salt is produced in the form of hydrochloric acid and sodium hydroxide solution. The zero-emission process reduces the cost of softening agents, realizes the resource recovery of the primary and the divalent salts, reduces the pretreatment dosing cost and the dosage workload, and reduces the desalting load of the whole system.
The application has the advantages that:
1. the ozone is adopted to oxidize the membrane concentrated solution to destroy the scale inhibition effect of the scale inhibitor, so that scale-forming salts such as calcium sulfate and calcium carbonate in the membrane concentrated water can be separated out, the wastewater recovery rate is improved, and the long-period effective operation of a wastewater treatment unit is ensured.
2. Partial COD in the wastewater can be removed while the ozone oxidation unit is introduced to treat the membrane concentrated solution, so that the membrane pollution caused by the accumulation of the COD in the zero-discharge process is prevented.
3. The process flow is simple and convenient to operate, no by-product is generated, the storage and sale of miscellaneous salt or waste water are not required to be considered, and compared with the prior art, the integral operation cost can be greatly reduced, and the social and economic benefits are better achieved.
Drawings
Fig. 1 is a flow chart of a method for removing scale inhibitors from reverse osmosis concentrated water according to an embodiment of the present invention.
Fig. 2 is a flow chart of a method for removing scale inhibitors from nanofiltration concentrate water according to an embodiment of the present invention.
Detailed Description
The present invention will be more fully understood by those skilled in the art by describing the present invention in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention in any way.
The main ion concentrations of the water quality of the reverse osmosis concentrated water of the saline wastewater at the pilot plant site of a certain power plant adopted in the following examples 1 to 10 are shown in table 1, and the supersaturation degree of calcium sulfate of the reverse osmosis concentrated water is 280%.
TABLE 1
| pH | Na + | Ca 2+ | Mg 2+ | SO 4 2- | Cl - |
| 6.2 | 4017mg/L | 1300mg/L | 5mg/L | 6800mg/L | 5000mg/L |
In the following examples 1-10, the following examples,
calcium sulfate supersaturation =100% (% by mass molar concentration of calcium sulfate in salt solution/solubility corrected for homoionic effects (i.e. saturation molar concentration of calcium sulfate)).
The main component of the used scale inhibitor A is polycarboxylic acid molecules which are purchased from Nalcidae Beijing environmental protection technology development Limited company;
the main component organic phosphonic acid molecules of the scale inhibitor B are purchased from Naalco Beijing environmental protection technology development Limited company;
the main components of the scale inhibitor C are organic phosphonic acid molecules and polycarboxylic acid molecules, which are purchased from special chemical engineering Limited.
Example 1
Adopting reverse osmosis concentrated water as shown in Table 1, wherein the reverse osmosis concentrated water contains 10ppm of scale inhibitor A, adjusting the pH value to 9.0, introducing ozone gas generated by an ozone generator into the reverse osmosis concentrated water through an aeration disc, and allowing the ozone gas to enter a crystallization tank for reaction, wherein the ozone adding concentration is 120mg/L based on each liter of reverse osmosis concentrated water, the reaction temperature is 22 ℃, and the reaction time is 20min.
And adding 2mg/L polyacrylamide flocculant into the crystallization tank for crystallization at 22 ℃ for 30min, wherein the supersaturation degree of calcium sulfate in the effluent of the crystallization tank is 122%. The effluent of the crystallization tank is reused as reverse osmosis inlet water, the reverse osmosis unit operates stably, and the phenomenon of effluent supersaturation degree increase or membrane scaling does not occur.
Example 2
The method is basically the same as that of the example 1, except that the reverse osmosis concentrated water contains 40ppm of the scale inhibitor B, and finally, the supersaturation degree of the calcium sulfate of the effluent of the crystallization tank is 110 percent.
Example 3
The method is basically the same as the example 1, except that the reverse osmosis concentrated water contains 40ppm of scale inhibitor C, and finally, the supersaturation degree of the calcium sulfate in the effluent of the crystallization tank is 128%.
Example 4
The method is basically the same as that of the example 1, except that the reverse osmosis concentrated water contains 20ppm of the scale inhibitor C, and finally, the supersaturation degree of the calcium sulfate in the effluent of the crystallization tank is 113%.
Example 5
The method is basically the same as that of the example 1, except that the reverse osmosis concentrated water contains 100ppm of the scale inhibitor C, and finally, the supersaturation degree of the calcium sulfate in the effluent of the crystallization tank is 230 percent.
Example 6
The method is basically the same as in example 3, except that the pH of the reverse osmosis concentrated water is adjusted to 10.0, and finally, the supersaturation degree of calcium sulfate in the effluent of the crystallization tank is 120%.
Example 7
The process was essentially the same as in example 3, except that the pH of the reverse osmosis concentrate was adjusted to 8.0 and finally the degree of supersaturation of calcium sulfate in the crystallizer effluent was 130%.
Example 8
The process was essentially the same as in example 3, except that the pH of the reverse osmosis concentrate was adjusted to 4.0 and finally the supersaturation of calcium sulfate in the crystallizer effluent was 180%.
Example 9
The method is substantially the same as that of example 3, except that the concentration of ozone added is 60mg/L, and finally, the supersaturation degree of calcium sulfate in the effluent of the crystallization tank is 155%.
Example 10
The method is substantially the same as in example 3, except that the concentration of ozone added is 30mg/L, and finally, the supersaturation degree of calcium sulfate in the effluent of the crystallization tank is 210%.
In the invention, the method of treating the reverse osmosis concentrated solution by ozone oxidation is introduced to destroy the scale inhibitor in the reverse osmosis concentrated solution, improve the water recovery rate of a reverse osmosis system and ensure the long-term stability of the operation of the membrane; meanwhile, divalent calcium sulfate in the concentrated water can be smoothly crystallized and separated out after entering the pre-settling tank.
Example 11
Referring to fig. 2, this example is provided to illustrate a method for treating desulfurization wastewater according to the present invention, which can remove scale inhibitors from nanofiltration concentrate.
The water quality of a certain desulfurized wastewater is shown in Table 2.
TABLE 2
| pH | Na + | Ca 2+ | Mg 2+ | SO 4 2- | Cl - |
| 6.7 | 3662mg/L | 1000mg/L | 2000mg/L | 7000mg/L | 8000mg/L |
In this example, the calcium sulfate supersaturation =100% (% by mass molar concentration of calcium sulfate in the salt solution/solubility corrected for the homoionic effect (i.e. saturation molar concentration of calcium sulfate)).
The treatment method of the desulfurization wastewater comprises the following steps:
step 1, adding a calcium hydroxide solution with the mass concentration of 10% into power plant desulfurization wastewater of 15t/h, adjusting the pH to 9.5, simultaneously adding organic sulfur (2 wt% of TMT-15) and a coagulant aid (5 wt% of PAM) for first softening pretreatment, reacting for 30min, and clarifying for 60min to obtain clarified effluent;
step 2, adding a calcium hydroxide solution with the mass concentration of 10% into the clear effluent obtained in the step 1 again, continuously adjusting the pH value to 11.5, adding a coagulant aid (5% of PAM) to react for 30min for second softening pretreatment, and staying for 30min for sedimentation to obtain magnesium hydroxide precipitate and softened desulfurization wastewater;
and 3, adding hydrochloric acid into the softened desulfurization wastewater obtained in the step 2 to adjust the pH value to 7.4, and filtering out suspended matters through sand filtration and ultrafiltration. Adding 10ppm of organic phosphine scale inhibitor into the super-filtered water, and performing nanofiltration treatment in a nanofiltration system to obtain nanofiltration concentrated water and nanofiltration produced water, wherein the supersaturation degree of calcium sulfate in the nanofiltration concentrated water is 280-350%;
step 4, adjusting the pH value of the nanofiltration concentrated water obtained in the step 3 to 9, and bringing ozone gas generated by an ozone generator into the nanofiltration concentrated water through a gas-liquid mixing pump, wherein the adding concentration of the ozone is 80mg/L in terms of per liter of the nanofiltration concentrated water, and the reaction temperature is 22 ℃;
and 5, introducing the mixed stream of the ozone and the nanofiltration concentrated water obtained in the step 4 into a crystallization tank for carrying out ozone reaction and crystallization at the temperature of 22 ℃ for 60min. Crystallizing to separate out solids, generating crystallization water, and refluxing the obtained crystallization water to nanofiltration water for recycling, wherein the supersaturation degree of calcium sulfate in the crystallization water is-120%;
step 6, the nanofiltration produced water obtained in the step 3 enters a reverse osmosis-bipolar membrane electrodialysis system for reverse osmosis treatment to obtain reverse osmosis concentrated water and reverse osmosis produced water, and the reverse osmosis produced water is recycled as reuse water;
and 7, performing bipolar membrane electrodialysis treatment on the reverse osmosis concentrated water obtained in the step 6, and electrolyzing to generate electrodialysis water and high-purity NaOH and HCl solutions, wherein the electrodialysis water is refluxed to the reverse osmosis treatment for recycling, and the NaOH solution and the HCl solution are returned to the softening pretreatment for recycling.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described in relation to an exemplary embodiment, and it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.
Claims (10)
1. A wastewater treatment method comprises the step of carrying out first contact on wastewater containing a scale inhibitor and ozone gas so as to reduce the content of the scale inhibitor in the wastewater.
2. The method of claim 1, wherein the scale inhibitor comprises a polycarboxylic acid molecule and/or an organic phosphonic acid molecule; the wastewater comprises concentrated water after membrane concentration, and is preferably selected from reverse osmosis concentrated water and/or nanofiltration concentrated water.
3. The method according to claim 1 or 2, characterized in that the pH of the wastewater is 6-10, preferably 8-10; and/or
In the wastewater, the concentration of the scale inhibitor is 5-100ppm; and/or
The adding concentration of the ozone gas is 20-150mg/L, preferably 50-140mg/L; and/or
The first contact time is 10-40min, preferably 20-40min; and/or the temperature of the first contacting is 10-40 ℃.
4. A method according to any one of claims 1-3, characterized in that the ozone gas is produced by an ozone generator, preferably the ozone gas is passed into the waste water by means of an aeration disc or an eductor.
5. The method according to any one of claims 1 to 4, further comprising a second contacting of the wastewater after the first contacting with a flocculant to obtain a precipitate and a wastewater with reduced hardness, preferably wherein the wastewater with reduced hardness is recycled.
6. The method of claim 5, wherein the flocculant comprises at least one selected from the group consisting of polyacrylamide, polyaluminum sulfate, and polyferric sulfate; and/or
The addition amount of the flocculating agent is 2-10mg/L; and/or
The second contact time is 10-40min, preferably 20-40min; and/or the temperature of the second contacting is 10-40 ℃.
7. A method according to claim 5 or 6, characterized in that the supersaturation of scaling salts such as calcium sulphate and/or calcium carbonate in the hardness-reduced wastewater is reduced to 100-230%, preferably 100-150%.
8. Use of a method according to any one of claims 1 to 7 in a method of treating desulphurised waste water.
9. The use according to claim 8, wherein the desulfurized wastewater contains a scale inhibitor, preferably in a concentration of 5-100ppm.
10. The use according to claim 8 or 9, characterized in that the method for treating desulfurization waste water comprises the following steps:
step A: contacting the desulfurization wastewater with a calcium hydroxide solution, and performing softening pretreatment to obtain a solid precipitate and softened desulfurization wastewater;
and B: contacting the softened desulfurization wastewater with a scale inhibitor, and performing nanofiltration treatment to obtain nanofiltration concentrated water and nanofiltration produced water;
and C: b, enabling the nanofiltration concentrated water obtained in the step B to contact with ozone gas, and carrying out ozone treatment to obtain nanofiltration concentrated water after ozone treatment;
step D: optionally contacting the ozone-treated nanofiltration concentrated water with a flocculating agent to crystallize and separate out solids and produce crystallized water;
step E: b, performing reverse osmosis treatment on the nanofiltration produced water obtained in the step B to obtain reverse osmosis concentrated water and reverse osmosis produced water;
preferably, the method for treating desulfurization wastewater further comprises the step F: carrying out bipolar membrane electrodialysis treatment on the reverse osmosis concentrated water to obtain a sodium hydroxide solution, a hydrochloric acid solution and electrodialysis produced water, wherein the sodium hydroxide solution and the hydrochloric acid solution are returned to softening pretreatment for recycling;
more preferably, the crystallization water is refluxed to nanofiltration water for recycling; and/or the reverse osmosis produced water is recycled as reuse water; and/or the electrodialysis water is returned to the reverse osmosis treatment for recycling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110522883.2A CN115340225A (en) | 2021-05-13 | 2021-05-13 | Wastewater treatment method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110522883.2A CN115340225A (en) | 2021-05-13 | 2021-05-13 | Wastewater treatment method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115340225A true CN115340225A (en) | 2022-11-15 |
Family
ID=83946569
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110522883.2A Pending CN115340225A (en) | 2021-05-13 | 2021-05-13 | Wastewater treatment method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115340225A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20150368137A1 (en) * | 2013-02-01 | 2015-12-24 | Addleman Enterprises, Inc. | Method and apparatus for treating natural gas and oil well waste waters for removal of contaminants and dissolved solids |
| US20170368476A1 (en) * | 2016-06-27 | 2017-12-28 | Enviro Water Minerals Company, Inc. | System and method for removal of scale forming components |
| CN107662987A (en) * | 2016-07-29 | 2018-02-06 | 通用电气公司 | The method and system of useful chemicals is produced from salt solution |
| CN108218072A (en) * | 2018-03-22 | 2018-06-29 | 山东泰禾环保科技股份有限公司 | Haline water alkali-making process and its device |
| CN211896391U (en) * | 2020-03-05 | 2020-11-10 | 山东蓝然环境科技有限公司 | Treatment device for high-salinity wastewater in sulfuric acid method titanium dioxide industry |
| CN112678985A (en) * | 2019-10-18 | 2021-04-20 | 中国石油化工股份有限公司 | Method and device for pretreating negative hardness water containing scale inhibitor |
-
2021
- 2021-05-13 CN CN202110522883.2A patent/CN115340225A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20150368137A1 (en) * | 2013-02-01 | 2015-12-24 | Addleman Enterprises, Inc. | Method and apparatus for treating natural gas and oil well waste waters for removal of contaminants and dissolved solids |
| US20170368476A1 (en) * | 2016-06-27 | 2017-12-28 | Enviro Water Minerals Company, Inc. | System and method for removal of scale forming components |
| CN107662987A (en) * | 2016-07-29 | 2018-02-06 | 通用电气公司 | The method and system of useful chemicals is produced from salt solution |
| CN108218072A (en) * | 2018-03-22 | 2018-06-29 | 山东泰禾环保科技股份有限公司 | Haline water alkali-making process and its device |
| CN112678985A (en) * | 2019-10-18 | 2021-04-20 | 中国石油化工股份有限公司 | Method and device for pretreating negative hardness water containing scale inhibitor |
| CN211896391U (en) * | 2020-03-05 | 2020-11-10 | 山东蓝然环境科技有限公司 | Treatment device for high-salinity wastewater in sulfuric acid method titanium dioxide industry |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6764850B2 (en) | Methods and systems for the treatment of brine wastewater | |
| CN108623063B (en) | Desulfurization wastewater treatment method and system | |
| CN108529802B (en) | Zero-discharge process for discharging high-salt-content wastewater in titanium dioxide production | |
| CN106430786B (en) | Desulfurization wastewater treatment method and device | |
| KR100743146B1 (en) | Pretreatment method of desulfurization and denitrification waste water | |
| CN106746115A (en) | Desulfurization wastewater recycling processing method and processing system | |
| CN110683709A (en) | Zero-discharge treatment method for fluorine-containing wastewater | |
| CN111170520A (en) | Treatment process and treatment system for desulfurization wastewater | |
| CN111170544A (en) | Zero discharge system and method for pretreatment wastewater of active coke desulfurization and denitrification and salt preparation from rich gas | |
| CN113461236A (en) | Zero discharge system that high salt waste water of power plant divides matter to handle | |
| CN112225355A (en) | Shale gas recovery flowback fluid treatment process | |
| CN113003845B (en) | Zero-emission treatment process and system for sewage with high sulfate content and high COD (chemical oxygen demand) | |
| CN108117223B (en) | Zero-discharge treatment method for salt-containing wastewater | |
| CN110407351B (en) | Treatment method of salt-containing wastewater | |
| CN219950761U (en) | High-salt fluorine-containing wastewater defluorination and resource utilization treatment system | |
| Gonzales et al. | Treatment of high-strength wastewater with coupled flocculation and membrane filtration prior to ammoniacal nitrogen enrichment by osmotically assisted reverse osmosis | |
| CN112573720A (en) | Thermal power plant desulfurization wastewater zero-discharge system and method | |
| CN112573767A (en) | Membrane-method salt separation recycling treatment system for high-salinity wastewater in petroleum refining industry | |
| CN115340225A (en) | Wastewater treatment method and application thereof | |
| CN112919709A (en) | Process for treating high-salt high-concentration organic wastewater | |
| CN110156237A (en) | A kind of waste water water conservancy recovery method | |
| CN114751564A (en) | Coking wastewater treatment method | |
| CN111099774A (en) | Desulfurization wastewater treatment method and system | |
| CN113754164A (en) | Desulfurization wastewater treatment method and system | |
| CN113461237A (en) | Zero discharge system for salt wastewater treatment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |