High-salinity wastewater recovery treatment system

Abstract

The invention discloses a high-salinity wastewater recovery treatment system. The system comprises a water storage tank, a water supply pump I, a sand filter, an FA pretreatment device, an FA water outlet tank, an FA water outlet pump, a security filter, a first-stage concentrated water reverse osmosis device, a first-stage concentrated water tank, a water supply pump II, a second-stage concentrated water ultrafiltration device, a second-stage concentrated water reverse osmosis device, a third-stage concentrated water ultrafiltration device, a third-stage concentrated water reverse osmosis device, a third-stage concentrated water tank and an MVR evaporation treatment device which are connected in sequence. According to the invention, through the combination of three-stage ultrafiltration and reverse osmosis, the hardness and turbidity of the high-salinity wastewater in chemical production are effectively reduced, suspended solids, colloids, macromolecular substances, bacteria, BOD, COD and other impurities in the high-salinity wastewater are removed, the separated water and salt are recycled, and the device is simple in configuration, high in automation degree and convenient to operate.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical water treatment, and in particular relates to a high-salt wastewater recovery and treatment system. Background Art

[0002] In the chemical industry, there is a large amount of high-salt wastewater, which is usually sent directly to the sewage treatment section, resulting in a waste of water resources. The existing high-salt wastewater treatment system has the disadvantages of low desalination efficiency, low degree of automation, high energy consumption, and large equipment footprint.

[0003] Chinese patent CN 204211580 U discloses a desalted water treatment device, comprising a raw water tank, an ultrafiltration security filter, an ultrafiltration device, an ultrafiltration pool, a primary security filter, a primary reverse osmosis device, a primary reverse osmosis water tank, a secondary security filter, a secondary reverse osmosis device, and a secondary reverse osmosis water tank connected in sequence through pipelines, wherein the secondary reverse osmosis water tank is connected to an electrodialysis ion exchange device through a pipeline, and the electrodialysis ion exchange device is connected to a desalted water tank through a pipeline. Although this utility model solves the problem of regenerated acid and alkali discharge in ion exchange in the existing desalted water treatment, improves the recycling of water resources, and reduces the pollution of wastewater discharge to the environment, it has a low degree of automation and a high labor cost.

[0004] Chinese patent CN 212640201 U discloses a novel desalted water treatment system, including a raw water pool, the raw water pool is sequentially connected to a desalted water tank via a raw water lift pump, a multi-media filter, an activated carbon filter, an ultrafiltration water production pool, a primary RO lift pump, a primary reverse osmosis system, an interstage water tank, a secondary reverse osmosis system, a fresh water tank, an EDI booster pump, and an EDI device; a first pipeline mixer is connected between the raw water lift pump and the multi-media filter, and the inner cavity of the first pipeline mixer is connected to a bactericide dosing device and a non-oxidizing bactericide dosing device; a second pipeline mixer is connected between the primary RO lift pump and the primary reverse osmosis system, and the inner cavity of the second pipeline mixer is connected to a reducing agent dosing device and a cationic scale dosing device. After filtering through the multi-media filter and the activated carbon filter, the utility model further desalts through the EDI device, which can reduce the conductivity of the desalted water to below 0.2μS / cm. The main purpose of this utility model is to reduce the conductivity of desalted water, but it cannot completely remove COD, BOD and other soluble solids; and the activated carbon needs to be replaced regularly, and the production cost is relatively high.

[0005] Chinese patent CN 212640201 U discloses a desalted water treatment device, including a pretreatment system, a membrane separation system and a post-treatment system connected in sequence; the pretreatment system includes a raw water tank, a primary filtration component and a precision filtration component arranged in sequence; the membrane separation system includes a primary reverse osmosis component, a primary water tank, a secondary reverse osmosis component and a secondary water tank arranged in sequence; the post-treatment system includes an EDI treatment component, a pure water tank, an ultraviolet sterilizer and an ultrafiltration membrane component arranged in sequence, and the above equipment are all connected through pipelines. The quartz sand filter and activated carbon filter used in the utility model need to replace the quartz sand and activated carbon after long-term use to ensure the water intake, and the production cost is relatively high. Summary of the invention

[0006] In order to effectively solve the existing problems, it is necessary to invent a high-salt wastewater recovery and treatment system.

[0007] The objective of the present invention is achieved through the following technical scheme: a high-salt wastewater recovery and treatment system, comprising a water storage tank, a sand filter, an FA pretreatment device, an FA water outlet tank, a security filter, a primary concentrated water reverse osmosis, a primary concentrated water tank, a secondary concentrated water ultrafiltration device, a secondary concentrated water reverse osmosis, a tertiary concentrated water ultrafiltration device, a tertiary concentrated water reverse osmosis, a tertiary concentrated water tank, and an MVR evaporation treatment device connected in sequence.

[0008] Furthermore, a water supply pump I is provided on the pipeline between the water storage tank and the sand filter.

[0009] Furthermore, a FA water outlet pump is provided on the pipeline between the FA water outlet pool and the security filter.

[0010] Furthermore, a water supply pump II is provided on the pipeline between the primary concentrated water tank and the secondary concentrated water ultrafiltration device.

[0011] Furthermore, the first-stage concentrated water reverse osmosis, the second-stage concentrated water reverse osmosis, and the second-stage concentrated water reverse osmosis are respectively provided with two outlets, one outlet is the produced water outlet, and the other outlet is the concentrated water outlet, and the produced water outlets are all connected to the circulating water replenishment network through pipelines.

[0012] Furthermore, a cleaning system is provided on the pipeline connecting the outlet of the water supply pump II and the outlet of the tertiary concentrated water reverse osmosis water product.

[0013] Furthermore, the cleaning system includes a forward wash valve, a concentrated water discharge valve, a water production valve, a backwash tank inlet valve, a backwash tank, a backwash pump, an alkali dosing device, an acid dosing device, a sodium hypochlorite dosing device, and a backwash valve.

[0014] Furthermore, the alkali added to the cleaning system by the alkali dosing device is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 0.1-0.3% (wt), the main purpose of which is to prevent the growth of bacteria and the excessive accumulation of pollutants.

[0015] Furthermore, the acid added to the cleaning system by the acid dosing device is a hydrochloric acid solution or a sulfuric acid solution with a concentration of 0.2-0.5% (wt), the main purpose of which is to prevent the growth of bacteria and the excessive accumulation of pollutants.

[0016] Furthermore, the sodium hypochlorite dosing device adds the sodium hypochlorite solution into the cleaning system with an effective chlorine concentration of 100-200 ppm, the main purpose of which is sterilization.

[0017] Compared with the prior art, the present invention has the following advantages: (1) The present invention effectively reduces the hardness and turbidity of high-salt wastewater in chemical production by combining three-stage ultrafiltration and reverse osmosis, removes suspended solids, colloids, macromolecular substances, bacteria, BOD, COD and other impurities in the high-salt wastewater, and recycles the separated water and salt to reduce production costs; (2) The reverse osmosis membrane used in the reverse osmosis device of the present invention is a semi-permeable roll membrane. When raw water is sent to the reverse osmosis membrane at a certain pressure, the water passes through the tiny pores on the membrane and is collected to obtain pure water, while impurities in the water such as soluble solids, organic matter, colloids and bacteria are retained by the reverse osmosis membrane, concentrated in the intercepted liquid and removed; the present invention uses three-stage reverse osmosis to remove more than 97% of soluble solids, more than 99% of organic matter and colloids, and almost 100% of bacteria in raw water. (3) The present invention is provided with a cleaning system to clean the ultrafiltration device and the reverse osmosis device, thereby preventing the membrane surfaces of the ultrafiltration device and the reverse osmosis device from being blocked by trace insoluble salts, microorganisms, organic and inorganic impurity particles in the high salt water, thereby greatly improving the water production and desalination rate; (4) The device of the present invention has a simple configuration, a high degree of automation, and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0019] Figure 1 It is a simplified process flow diagram of the present invention.

[0020] Figure 2 Schematic diagram of the cleaning system of the present invention.

[0021] Figure 1-2Among them, 1 is a water storage tank, 2 is a water supply pump I, 3 is a sand filter, 4 is a FA pretreatment device, 5 is a FA water outlet tank, 6 is a FA water outlet pump, 7 is a security filter, 8 is a primary concentrated water reverse osmosis, 9 is a primary concentrated water tank, 10 is a water supply pump II, 11 is a secondary concentrated water ultrafiltration device, 12 is a secondary concentrated water reverse osmosis, 13 is a tertiary concentrated water ultrafiltration device, 14 is a tertiary concentrated water reverse osmosis, 15 is a tertiary concentrated water tank, 16 is an MVR evaporation treatment device, 17 is a cleaning system, 17.1 is a forward wash valve, 17.2 is a concentrated water discharge valve, 17.3 is a water production valve, 17.4 is a backwash water tank inlet valve, 17.5 is a backwash water tank, 17.6 is a backwash pump, 17.7 is an alkali dosing device, 17.8 is an acid dosing device, 17.9 is a sodium hypochlorite dosing device, and 17.10 is a backwash valve. DETAILED DESCRIPTION

[0022] See attached Figure 1-2 An embodiment of the present invention provides a high-salt wastewater recovery and treatment system, which includes a water storage tank, a sand filter, an FA pretreatment device, an FA water outlet tank, a security filter, a primary concentrated water reverse osmosis, a primary concentrated water tank, a secondary concentrated water ultrafiltration device, a secondary concentrated water reverse osmosis, a tertiary concentrated water ultrafiltration device, a tertiary concentrated water reverse osmosis, a tertiary concentrated water tank, and an MVR evaporation treatment device, which are connected in sequence.

[0023] Another embodiment is different in that a water supply pump I is provided on the pipeline between the water storage tank and the sand filter to deliver the high-salt wastewater in the water storage tank to the sand filter to filter the suspended matter in the water.

[0024] Another embodiment is different in that a FA outlet pump is provided on the pipeline between the FA outlet tank and the security filter to deliver the wastewater stored in the FA outlet tank after the hardness and turbidity are reduced in the FA pretreatment device to the security filter. The FA pretreatment device mainly includes reaction, coagulation, flocculation, precipitation and filtration processes. Sodium hydroxide solution is added to the high-salt wastewater entering the FA pretreatment device to control the pH at 11-12, and then sodium carbonate solution is added. The calcium carbonate and magnesium carbonate generated by the reaction are added to the coagulant after being impacted and stirred by the water flow. A mixing tank is set in the FA pretreatment device. The coagulant and high-salt wastewater are quickly mixed through the baffle stirring in the mixing tank; a high-efficiency sedimentation tank is also set in the FA pretreatment device. The high-efficiency sedimentation tank is divided into two parts: flocculation and sedimentation. Flocculants are added to the flocculation part to re-form larger flocs that are easy to settle. The sedimentation part is divided into a pre-sedimentation area and an inclined tube sedimentation area by a partition. In the pre-sedimentation area, the flocs that are easy to settle quickly settle, and the tiny flocs that have not yet settled and are not easy to settle are captured by the inclined tube. Finally, the wastewater with reduced hardness and turbidity enters the FA effluent tank for storage, and the settled sludge enters the sewage treatment system.

[0025] Another embodiment is different in that a water supply pump II is provided on the pipeline between the primary concentrated water tank and the secondary concentrated water ultrafiltration device.

[0026] Another embodiment is different in that the first-stage concentrated water reverse osmosis, the second-stage concentrated water reverse osmosis, and the second-stage concentrated water reverse osmosis are respectively provided with two outlets, one outlet is the produced water outlet, and the other outlet is the concentrated water outlet, and the produced water outlets are all connected to the circulating water replenishment network through pipelines.

[0027] The fresh water separated by the three-stage concentrated water reverse osmosis is sent from the water production outlet to the circulating water replenishment network. The concentrated water enters the three-stage concentrated water tank for buffering through the concentrated water outlet and then enters the MVR evaporation treatment device. The concentrated water undergoes continuous high-temperature evaporation in the MVR evaporation treatment device to form crystalline salt.

[0028] As the running time of the device increases, trace insoluble salts, microorganisms, organic and inorganic impurity particles entering the secondary concentrated water ultrafiltration device, the secondary concentrated water reverse osmosis device, the tertiary concentrated water ultrafiltration device, and the tertiary concentrated water reverse osmosis device will clog the membrane surface. Therefore, the present invention provides a cleaning system on the pipeline connecting the outlet of the water supply pump II and the tertiary concentrated water reverse osmosis water output outlet.

[0029] Another embodiment is different in that the cleaning system includes a forward wash valve, a concentrated water discharge valve, a water production valve, a backwash tank inlet valve, a backwash tank, a backwash pump, an alkali dosing device, an acid dosing device, a sodium hypochlorite dosing device, and a backwash valve.

[0030] Another embodiment is different in that the alkali added to the cleaning system by the alkali dosing device is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 0.1-0.3% (wt), the main purpose of which is to prevent the growth of bacteria and the excessive accumulation of pollutants.

[0031] Another embodiment is different in that the acid added to the cleaning system by the acid adding device is a hydrochloric acid solution or a sulfuric acid solution with a concentration of 0.2-0.5% (wt), the main purpose of which is to prevent the growth of bacteria and the excessive accumulation of pollutants.

[0032] Another embodiment is different in that the sodium hypochlorite dosing device adds the sodium hypochlorite solution into the cleaning system with an effective chlorine concentration of 100-200 ppm, the main purpose of which is sterilization.

[0033] The operation process of the cleaning system includes three modes: forward washing, backwashing, and chemical enhanced backwashing. During forward washing, the forward washing valve and the concentrated water discharge valve are opened, the water production valve and the backwash water tank inlet valve are closed, and the concentrated water from the water supply pump II is used to flush the sediments polluted by the membrane by generating tangential acceleration on the membrane surface to increase the backwashing effect and fully restore the permeability of the ultrafiltration device and the reverse osmosis device. During backwashing, the water flow direction is opposite to the water production direction, the forward washing valve, the concentrated water discharge valve, and the water production valve are closed, the backwash water tank inlet valve and the backwash valve are opened, and the water produced from the three-stage concentrated water reverse osmosis water outlet is used as the backwash water to avoid contamination of the membrane on the water production side and clogging of the membrane pores by impurities. During chemically enhanced backwashing, the water flow direction is the same as the backwashing direction. Chemically enhanced backwashing is divided into three modes: chemically enhanced alkaline washing, chemically enhanced acid washing, and chemically enhanced sterilization. The time, frequency, and mode of chemically enhanced backwashing are determined according to the pollution situation. Chemically enhanced alkaline washing and chemically enhanced acid washing are generally not carried out separately in a chemically enhanced backwashing process. Instead, chemically enhanced alkaline washing is carried out first and then chemically enhanced acid washing, or chemically enhanced acid washing is carried out first and then chemically enhanced alkaline washing, or only chemically enhanced alkaline washing is carried out, or only chemically enhanced acid washing is carried out. The chemically enhanced sterilization process can be carried out irregularly according to production needs.

[0034] Another embodiment is different in that the COD content of the high-salinity wastewater entering the water storage tank is less than 120 mg / L, the ammonia nitrogen content is less than 20 mg / L, the turbidity is less than 10 NTU, and the pH is 6-9.

[0035] Another embodiment is different in that the water sent from the tertiary concentrated water reverse osmosis water outlet to the circulating water replenishment network has a COD content of <50 mg / L, an ammonia nitrogen content of <5 mg / L, a turbidity of <5 NTU, and a pH of 6-9.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-salinity wastewater recovery and treatment system, characterized in that: The device comprises a water storage tank, a sand filter, a FA pretreatment device, a FA water outlet tank, a security filter, a primary concentrated water reverse osmosis, a primary concentrated water tank, a secondary concentrated water ultrafiltration device, a secondary concentrated water reverse osmosis, a tertiary concentrated water ultrafiltration device, a tertiary concentrated water reverse osmosis, a tertiary concentrated water tank, and an MVR evaporation treatment device which are connected in sequence; a water supply pump I is provided on the pipeline between the water storage tank and the sand filter; a FA water outlet pump is provided on the pipeline between the FA water outlet tank and the security filter; a water supply pump II is provided on the pipeline between the primary concentrated water tank and the secondary concentrated water ultrafiltration device.

2. A high-salinity wastewater recovery and treatment system according to claim 1, characterized in that: The first-stage concentrated water reverse osmosis, the second-stage concentrated water reverse osmosis, and the second-stage concentrated water reverse osmosis are respectively provided with two outlets, one outlet is the produced water outlet, and the other outlet is the concentrated water outlet. The produced water outlets are all connected to the circulating water replenishment network through pipelines.

3. A high-salinity wastewater recovery and treatment system according to claim 2, characterized in that: A cleaning system is set up on the pipeline connecting the outlet of water supply pump II and the outlet of tertiary concentrated water reverse osmosis water.

4. A high-salinity wastewater recovery and treatment system according to claim 3, characterized in that: The cleaning system comprises a forward cleaning valve, a concentrated water discharge valve, a water production valve, a backwash water tank inlet valve, a backwash water tank, a backwash pump, an alkali dosing device, an acid dosing device, a sodium hypochlorite dosing device, and a backwash valve.

5. A high-salinity wastewater recovery and treatment system according to claim 4, characterized in that: The alkali added into the cleaning system by the alkali dosing device is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 0.1-0.3% (wt).

6. A high-salinity wastewater recovery and treatment system according to claim 4, characterized in that: The acid added into the cleaning system by the acid adding device is a hydrochloric acid solution or a sulfuric acid solution with a concentration of 0.2-0.5% (wt).

7. A high-salinity wastewater recovery and treatment system according to claim 4, characterized in that: The effective chlorine concentration of the sodium hypochlorite solution added into the cleaning system by the sodium hypochlorite dosing device is 100-200ppm.

8. A high-salinity wastewater recovery and treatment system according to claim 2, characterized in that: The water sent from the tertiary concentrated water reverse osmosis water outlet to the circulating water makeup network has a COD content of <50mg / L, ammonia nitrogen content of <5mg / L, turbidity of <5NTU, and a pH of 6-9.

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