High-salinity wastewater resourceful treatment system and method

Abstract

The invention discloses a high-salinity wastewater resourceful treatment system and method. The system comprises a water sample detection and analysis system, a pretreatment system, an ozonization system, an ultrafiltration membrane system, a reverse osmosis system, a membrane distillation system, an electrolytic hydrogen production system, an ozone generation system and an evaporation system. Only reverse osmosis pure water, membrane distillation high-purity water, high-purity hydrogen and evaporated solid residues are generated in the whole process, and zero emission of high-salinity wastewater is achieved. Membrane distillation, electrolytic hydrogen production and ozonized water treatment are combined for use, so that zero discharge of wastewater is realized, and cyclic utilization of resources such as water, oxygen and a low-grade heat source is also realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial sewage resource utilization, and particularly relates to a high-salt wastewater resource treatment system and method. Background Art

[0002] Industrial high-salt wastewater, such as desulfurization wastewater, oilfield produced water, reverse osmosis concentrate, gasification ash water, boiler blowdown water, etc., has complex components, which are mainly divided into two categories: organic matter and inorganic salts, including K + 、Ca 2+ 、Na + 、Mg 2+ 、CO 3 2- 、NO 3 2- 、Cl - 、SO 4 2- 、suspended oil, emulsified oil, dissolved oil, low-carbon organic matter, heavy metals, cyanide, aromatic and heterocyclic compounds, radioactive elements, etc. It is difficult to discharge or reuse these substances through simple treatment.

[0003] Chinese Patent with application number CN201610457392.3 discloses a wastewater treatment system and a wastewater treatment method. The wastewater treatment system includes: a pretreatment system that adjusts and precipitates the wastewater to obtain pretreated wastewater; a first treatment system that anaerobically treats and microbially intercepts the pretreated wastewater, softens and membrane filters the wastewater after microbial interception to obtain softened membrane-filtered effluent; a second treatment system that converts free ammonia in the softened membrane-filtered effluent into ionic ammonium to obtain converted effluent, and performs high-pressure reverse osmosis treatment, material separation treatment, and evaporation crystallization treatment on the converted effluent. In the wastewater treatment system of this invention, each treatment unit in the technical process can relatively thoroughly remove specific pollutants, and at the same time create favorable treatment conditions for subsequent units, forming an innovative and complete combined process. However, this invention cannot achieve "zero discharge" of wastewater. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a high-salt wastewater resource treatment system and method, which only produces reverse osmosis pure water, membrane distillation high-purity water, high-purity hydrogen, and solid residues after evaporation throughout the process, achieving "zero discharge" of high-salt wastewater.

[0005] The technical solution of the present invention is as follows:

[0006] One of the purposes of the present invention is to provide a high-salt wastewater resource treatment system, including:

[0007] Water sample detection and analysis system: It conducts sampling and analysis on high-salt wastewater for at least three batches to obtain the pH, COD, TDS, hardness, and the content range values of various pollutants in the high-salt wastewater;

[0008] Pretreatment system: It conducts softening, flocculation, and sedimentation treatment on the detected and analyzed high-salt wastewater to obtain supernatant and pretreatment concentrate. The supernatant enters the next-stage ozonation system, and the pretreatment concentrate enters the evaporation system;

[0009] Ozonation system: It uses an ozone aeration device to make the supernatant fully contact with ozone to obtain ozonated effluent and ozonated concentrate. The ozonated effluent enters the next-stage ultrafiltration system, and the ozonated concentrate enters the evaporation system;

[0010] Ultrafiltration membrane system: It intercepts suspended solid particles, macromolecular polymers, and bacteria in the ozonated effluent to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate. The ultrafiltration membrane effluent enters the next-stage reverse osmosis system, and the ultrafiltration membrane concentrate enters the evaporation system;

[0011] Reverse osmosis system: It uses an RO protection filter and an RO membrane module to conduct reverse osmosis treatment on the ultrafiltration membrane effluent to obtain reverse osmosis high-purity water and reverse osmosis concentrate;

[0012] Membrane distillation system: It conducts membrane distillation treatment on the reverse osmosis concentrate to obtain membrane distillation high-purity water and membrane distillation concentrate;

[0013] Electrolytic hydrogen production system: It conducts electrolytic hydrogen production on the membrane distillation high-purity water to obtain and collect high-purity hydrogen and oxygen;

[0014] Ozone generation system: It uses the corona discharge method to make ozone mixed gas from the oxygen collected by the electrolytic hydrogen production system and transports it through pipelines to the ozone aeration device for ozonation treatment;

[0015] Evaporation system: It conducts evaporation treatment on the pretreatment concentrate, ozonated concentrate, ultrafiltration membrane concentrate, and membrane distillation concentrate to obtain solid residues.

[0016] Further, in the pretreatment system, the steps of the softening treatment include neutralization, precipitation, and flocculation reactions on the high-salt wastewater.

[0017] Further, in the ozonation system, the ozone is generated by an ozone generator.

[0018] Further, in the ozonation system, during the process of using the ozone aeration device to make the supernatant fully contact with ozone, a composite catalyst is also added.

[0019] Further, in the ozonation system, multiple-stage ozone aeration devices are set up.

[0020] Furthermore, the ultrafiltration membrane system comprises an ultrafiltration circulation pump, and the ultrafiltration membrane system changes the water production flux and water quality of the ultrafiltration membrane system by regulating the flow rate and pressure of the ultrafiltration circulation pump.

[0021] Furthermore, the reverse osmosis system includes a high-pressure pump, and the reverse osmosis system adjusts the flow rate of the concentrated liquid and the system recovery rate by controlling the operating pressure of the high-pressure pump.

[0022] Furthermore, the driving force of the membrane distillation system and the evaporation system is industrial low-grade waste heat.

[0023] Furthermore, in the electrolytic hydrogen production system, the electrolytic hydrogen production process is an alkaline electrolytic hydrogen production process or a PEM electrolytic hydrogen production process.

[0024] The second object of the present invention is to provide a method for resource treatment of high-salt wastewater, comprising the following steps:

[0025] Water sample testing and analysis: At least three batches of high-salinity wastewater shall be sampled and analyzed to obtain the pH, COD, TDS, hardness and content range values ​​of various pollutants of the high-salinity wastewater;

[0026] Pretreatment: Soften, flocculate and settle the high-salinity wastewater that has been tested and analyzed to remove most of the ions in the high-salinity wastewater and generate insoluble substances to settle them, thereby obtaining supernatant and pretreatment concentrate;

[0027] Ozonation treatment: using an ozone aeration device to fully contact the supernatant with ozone, removing most of the remaining heavy metal salts in the pre-treated precipitate, and reducing the COD value to obtain ozonated effluent and ozonated concentrated liquid;

[0028] Ultrafiltration membrane treatment: intercepting the suspended solid particles, macromolecular polymers and bacteria in the ozonated effluent to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate;

[0029] Reverse osmosis treatment: using RO protective filter and RO membrane group to perform reverse osmosis treatment on the effluent of the ultrafiltration membrane to obtain reverse osmosis high-purity water and reverse osmosis concentrated liquid;

[0030] Membrane distillation treatment: performing membrane distillation treatment on the reverse osmosis concentrated liquid to obtain membrane distillation high-purity water and membrane distillation concentrated liquid;

[0031] Electrolysis for hydrogen production: electrolyzing the membrane distillation high-purity water to produce hydrogen, and obtaining and collecting high-purity hydrogen and oxygen;

[0032] Ozone generation: The oxygen collected in the electrolytic hydrogen production process is converted into an ozone mixed gas by a corona discharge method in an ozone generator, and then transported to the ozone aeration device through a pipeline for ozonation treatment;

[0033] Evaporation treatment: The pre-treatment concentrated liquid, ozonation concentrated liquid, ultrafiltration membrane concentrated liquid, and membrane distillation concentrated liquid are subjected to evaporation treatment to obtain solid residues.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. A high-salt wastewater resource treatment system provided by the present invention realizes zero discharge of wastewater by combining membrane distillation with electrolytic hydrogen production and ozonation water treatment. At the same time, it also achieves the recycling of water, oxygen, and industrial low-grade waste heat. The water resource utilization rate of the whole system is greater than 85%.

[0036] 2. In the ozonation system of the present invention, during the process of making the supernatant fully contact with ozone by using the ozone aeration device, a composite catalyst is also added, which can accelerate the oxidation precipitation of heavy metal substances in the supernatant produced by the pre-treatment system.

[0037] 3. In the present invention, the ozonation system can achieve stepwise oxidation of the supernatant produced by the pre-treatment system by setting up a multi-stage ozone aeration device, thereby improving the reaction efficiency and product quality.

[0038] 4. In the present invention, since the operation energy consumption of the membrane distillation system and the evaporation system is low, industrial low-grade waste heat can be used as the driving force to achieve the purpose of recycling.

[0039] 5. In the present invention, the by-product oxygen of electrolytic water hydrogen production can be used to in-situ prepare ozone for the pre-treatment of the water inlet of the water treatment system, saving costs and realizing the reuse of resources. Description of the Drawings

[0040] Figure 1 It is a flow chart of a high-salt wastewater resource treatment method. Detailed Embodiments

[0041] The following combines preferred embodiments and refers to the attached Figure 1 , to further illustrate the present invention. In the scope disclosed in the present invention, the endpoints and any values of the ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values; for numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article; the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels without special instructions; the experimental methods in the following embodiments are conventional methods without special instructions.

[0042] Example 1

[0043] This embodiment provides a resource treatment system for high-salt wastewater, including:

[0044] Water sample detection and analysis system: It conducts sampling and analysis on the high-salt wastewater for at least three batches to obtain the pH, COD, TDS, hardness, and the content range values of various pollutants in the high-salt wastewater;

[0045] Pretreatment system: It conducts softening, flocculation, and sedimentation treatment on the high-salt wastewater after detection and analysis to remove most of the ions, generate insoluble substances, and sediment under the action of flocculants and coagulants to obtain supernatant and pretreatment concentrate. The supernatant enters the next-level ozonation system, and the pretreatment concentrate enters the evaporation system;

[0046] In this embodiment, the steps of the softening treatment include neutralization, precipitation, and flocculation reactions on the high-salt wastewater.

[0047] Ozonation system: It uses an ozone aeration device to make the supernatant fully contact with ozone, removes most of the remaining heavy metal salts in the wastewater, and reduces the COD value of the wastewater to obtain ozonated effluent and ozonated concentrate. The ozonated effluent enters the next-level ultrafiltration system, and the ozonated concentrate enters the evaporation system;

[0048] In this embodiment, the ozone is generated by an ozone generator. During the process of making the supernatant fully contact with ozone using the ozone aeration device in this embodiment, a composite catalyst is also added, which can accelerate the oxidation and precipitation of heavy metal substances in the supernatant generated by the pretreatment system; this embodiment also realizes the stepwise oxidation of the supernatant generated by the pretreatment system by setting up a multi-stage ozone aeration device, thereby improving the efficiency of the oxidation reaction and the quality of the products;

[0049] Ultrafiltration membrane system: It intercepts suspended solid particles, macromolecular polymers, and bacteria in the ozonated effluent to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate. The ultrafiltration membrane effluent enters the next-level reverse osmosis system, and the ultrafiltration membrane concentrate enters the evaporation system;

[0050] In this embodiment, the ultrafiltration membrane system includes an ultrafiltration circulation pump. In this embodiment, by regulating the flow rate and pressure of the ultrafiltration circulation pump, the water production flux and water production quality of the ultrafiltration membrane system are changed;

[0051] Reverse osmosis system: It conducts reverse osmosis treatment on the ultrafiltration membrane effluent using an RO protection filter and an RO membrane module to obtain reverse osmosis high-purity water and reverse osmosis concentrate;

[0052] In this embodiment, the reverse osmosis system includes a high-pressure pump. In this embodiment, by controlling the operating pressure of the high-pressure pump, the flow rate of the ultrafiltration membrane concentrate and the system recovery rate are adjusted.

[0053] Membrane distillation system: It performs membrane distillation treatment on the reverse osmosis concentrate to obtain membrane distillation high-purity water and membrane distillation concentrate;

[0054] In this embodiment, due to the low operating energy consumption of the membrane distillation system, the waste heat of the flue gas is used as the driving force of the membrane distillation system;

[0055] Electrolytic hydrogen production system: It electrolyzes the membrane distillation high-purity water to produce and collect high-purity hydrogen and oxygen;

[0056] In this embodiment, the process of electrolytic hydrogen production is the PEM electrolytic hydrogen production process;

[0057] Ozone generation system: It uses the corona discharge method to make the oxygen collected by the electrolytic hydrogen production system into an ozone mixture gas, and transports it through a pipeline to the ozone aeration device for ozonation treatment;

[0058] Evaporation system: It performs evaporation treatment on the pretreatment concentrate, ozonation concentrate, ultrafiltration membrane concentrate and membrane distillation concentrate to obtain solid residues.

[0059] In this embodiment, the driving force of the evaporation system is also the waste heat of the flue gas.

[0060] Example 2

[0061] This embodiment provides a method for resource treatment of high-salt wastewater, as Figure 1 shown, including the following steps:

[0062] Water sample detection and analysis: Sampling and analysis of the high-salt wastewater are carried out in 3 batches to obtain the pH, COD, TDS, hardness and the content range values of various pollutants of the high-salt wastewater, as shown in the following table;

[0063] Table 1 Summary table of high-salt wastewater detection and analysis results

[0064]

[0065]

[0066] Pretreatment: Softening, flocculation and sedimentation treatments are carried out to remove most of the ions in the high-salt wastewater, and insoluble substances are generated and settled to obtain supernatant and pretreatment concentrate. The specific process is as follows:

[0067] Through the chemical hardness removal process, the TDS and hardness of the wastewater are reduced to the ideal influent water quality range of the membrane distillation system for producing ultra-pure water. In this embodiment, the influent volume of the chemical hardness removal equipment is 100 t / d, the influent TDS is 100 g / L, and the total hardness is 90 g / L; the effluent volume is 95 t / d, the effluent TDS is 1 g / L, and the total hardness is 500 mg / L;

[0068] Adjust the pH value of the detected and analyzed high-salt wastewater to above 10, so that most of the calcium and magnesium ions and a small part of other ions in the high-salt wastewater form insoluble substances; add organic sulfides to react with some heavy metal ions to form insoluble sulfide precipitates;

[0069] Add a flocculant to coagulate the insoluble substances in the wastewater into large particles and deposit them. The addition of a coagulant aid can be used to further sediment them to obtain supernatant and pretreated concentrate;

[0070] Ozonation treatment: Make the supernatant fully contact with ozone by setting a secondary ozone aeration device, and accelerate the oxidation precipitation of heavy metal substances in the supernatant by adding a composite catalyst to remove most of the remaining heavy metal salts in the supernatant and reduce the COD value to obtain ozonated effluent and ozonated concentrate. The ratio of ozone to COD is 1.5:1;

[0071] Ultrafiltration membrane treatment: Retain suspended solid particles, macromolecular polymers and bacteria in the ozonated effluent to further reduce the COD value to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate;

[0072] In this embodiment, the water inflow of the ultrafiltration membrane system is 95t / d, the influent TDS is 1g / L, and the total hardness is 500mg / L; the water production of the ultrafiltration membrane effluent is 90t / d, the produced water TDS is 800mg / L, and the total hardness is 400mg / L;

[0073] Reverse osmosis treatment: Use an RO protection filter and an RO membrane module to perform reverse osmosis treatment on the ultrafiltration membrane effluent to obtain reverse osmosis high-purity water and reverse osmosis concentrate;

[0074] In this embodiment, the water inflow of the reverse osmosis system is 90t / h, the influent TDS is 500mg / L, and the total hardness is 400mg / L; the water production of the reverse osmosis high-purity water is 60t / d, the produced water TDS is 100mg / L, and the total hardness is 50mg / L; the water production of the reverse osmosis concentrate is 30t / d, the produced water TDS is 1300mg / L, and the total hardness is 1100mg / L;

[0075] Membrane distillation treatment: Perform membrane distillation treatment on the reverse osmosis concentrate to obtain membrane distillation high-purity water and membrane distillation concentrate;

[0076] In this embodiment, the inlet water temperature of the membrane distillation system is 80°C, the cooling water temperature is 30°C, the designed water inflow is 30t / d, the influent TDS is 1300mg / L, and the total hardness is 1100mg / L; the water production of the membrane distillation high-purity water is 27t / d, the produced water TDS is 50mg / L; the water production of the membrane distillation concentrate is 3t / d, the produced water TDS is 13g / L;

[0077] Electrolytic hydrogen production: Electrolyze the membrane distillation high-purity water to produce hydrogen by electrolysis. Based on alkaline electrolytic hydrogen production, high-purity hydrogen and oxygen are prepared and collected. In this embodiment, the designed hydrogen production capacity is 1000 Nm 3 / h, and the oxygen production capacity is 500 Nm 3 / h.

[0078] Ozone generation: Remove water from the by-product oxygen obtained by electrolytic hydrogen production. In the ozone generator, use the corona discharge method to convert oxygen into ozone mixture gas, and transport it to the ozone aeration device through pipelines for ozonation treatment; in this embodiment, the ozone generation efficiency is 100 kg / h, and the ozone content is 11 wt%;

[0079] Evaporation treatment: Perform evaporation treatment on the pretreatment concentrate, ozonation concentrate, ultrafiltration membrane concentrate and membrane distillation concentrate to obtain solid residues.

[0080] In this embodiment, the water resource reuse rate of the whole system is 87%.

[0081] In the electrolytic hydrogen production step of this embodiment, the PEM electrolytic hydrogen production process can also be selected to produce hydrogen and oxygen.

[0082] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A high-salinity wastewater resource treatment system, characterized in that: include: Water sample detection and analysis system: It samples and analyzes at least three batches of high-salinity wastewater to obtain the pH, COD, TDS, hardness and content range values ​​of various pollutants in the high-salinity wastewater; Pretreatment system: It softens, flocculates and settles the high-salinity wastewater that has been tested and analyzed to obtain supernatant and pretreatment concentrate. The supernatant enters the next-level ozonation system, and the pretreatment concentrate enters the evaporation system. Ozonation system: It uses an ozone aeration device to make the supernatant liquid fully contact with ozone to obtain ozonated effluent and ozonated concentrated liquid. The ozonated effluent enters the next-stage ultrafiltration system, and the ozonated concentrated liquid enters the evaporation system; Ultrafiltration membrane system: It intercepts suspended solid particles, macromolecular polymers and bacteria in the ozonated effluent to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate. The ultrafiltration membrane effluent enters the next-level reverse osmosis system, and the ultrafiltration membrane concentrate enters the evaporation system; Reverse osmosis system: It uses RO protection filter and RO membrane group to perform reverse osmosis treatment on the effluent of the ultrafiltration membrane to obtain reverse osmosis high-purity water and reverse osmosis concentrated liquid; Membrane distillation system: it performs membrane distillation treatment on the reverse osmosis concentrated liquid to obtain membrane distillation high-purity water and membrane distillation concentrated liquid; Electrolytic hydrogen production system: it electrolyzes the membrane distillation high-purity water to produce hydrogen, and obtains and collects high-purity hydrogen and oxygen; Ozone generation system: it uses corona discharge method to convert oxygen collected by electrolytic hydrogen production system into ozone mixed gas, and transports it to the ozone aeration device through pipelines for ozonation treatment; Evaporation system: It evaporates the pre-treated concentrated liquid, the ozonation concentrated liquid, the ultrafiltration membrane concentrated liquid and the membrane distillation concentrated liquid to obtain solid residue.

2. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: In the pretreatment system, the softening treatment step includes neutralization, precipitation and flocculation reactions on the high-salinity wastewater.

3. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: In the ozonation system, the ozone is generated by an ozone generator.

4. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: In the ozonation system, a composite catalyst is added during the process of fully contacting the supernatant with ozone by using the ozone aeration device.

5. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: In the ozonation system, a multi-stage ozone aeration device is provided.

6. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: The ultrafiltration membrane system comprises an ultrafiltration circulation pump, and the ultrafiltration membrane system changes the water production flux and water quality of the ultrafiltration membrane system by regulating the flow rate and pressure of the ultrafiltration circulation pump.

7. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: The reverse osmosis system comprises a high-pressure pump, and the reverse osmosis system adjusts the flow rate of the concentrate and the system recovery rate by controlling the operating pressure of the high-pressure pump.

8. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: The driving force of the membrane distillation system and the evaporation system is industrial low-grade waste heat.

9. A high-salinity wastewater resource treatment system according to claim 1, characterized in that: In the electrolytic hydrogen production system, the electrolytic hydrogen production process is an alkaline electrolytic hydrogen production process or a PEM electrolytic hydrogen production process.

10. A method for recycling high-salt wastewater, characterized in that: The following steps are involved: Water sample testing and analysis: At least three batches of high-salinity wastewater shall be sampled and analyzed to obtain the pH, COD, TDS, hardness and content range values ​​of various pollutants of the high-salinity wastewater; Pretreatment: Soften, flocculate and settle the high-salinity wastewater that has been tested and analyzed to remove most of the ions in the high-salinity wastewater and generate insoluble substances to settle them, thereby obtaining supernatant and pretreatment concentrate; Ozonation treatment: using an ozone aeration device to fully contact the supernatant with ozone, removing most of the heavy metal salts remaining in the pre-treated precipitate, and reducing the COD value to obtain ozonated effluent and ozonated concentrated liquid; Ultrafiltration membrane treatment: intercepting the suspended solid particles, macromolecular polymers and bacteria in the ozonated effluent to obtain ultrafiltration membrane effluent and ultrafiltration membrane concentrate; Reverse osmosis treatment: using RO protective filter and RO membrane group to perform reverse osmosis treatment on the effluent of the ultrafiltration membrane to obtain reverse osmosis high-purity water and reverse osmosis concentrated liquid; Membrane distillation treatment: performing membrane distillation treatment on the reverse osmosis concentrated liquid to obtain membrane distillation high-purity water and membrane distillation concentrated liquid; Electrolysis for hydrogen production: electrolysis of the membrane distillation high-purity water for hydrogen production, obtaining and collecting high-purity hydrogen and oxygen; Ozone generation: The oxygen collected in the electrolytic hydrogen production process is converted into an ozone mixed gas by a corona discharge method in an ozone generator, and then transported to the ozone aeration device through a pipeline for ozonation treatment; Evaporation treatment: The pretreatment concentrate, ozonation concentrate, ultrafiltration membrane concentrate and membrane distillation concentrate are evaporated to obtain a solid residue.

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