A device and process for treating phosphate-containing wastewater

Abstract

The invention discloses a device and a process for treating phosphate-containing wastewater, the device comprising: a precision filter, a membrane tube assembly, an electromagnetic flowmeter, a high-pressure pump and a control system; wherein the water inlet of the precision filter is used to access the wastewater to be treated; the membrane tube assembly is composed of a number of parallel membrane tubes, the water inlet end of each membrane tube is connected to the water outlet of the precision filter through a pipeline, and the water outlet end of the membrane tube is used to output purified water; the high-pressure pump is arranged on the pipeline in which the precision filter is connected to the membrane tube; the electromagnetic flowmeter is arranged on the pipeline in which the high-pressure pump is connected to the membrane tube; the control system is connected to the electromagnetic flowmeter and the high-pressure pump through a bus; and the precision filter is filled with fillers or modified fillers. The present invention performs filler adsorption and membrane adsorption on phosphorus-containing wastewater, and the treated water can be used for recovery and even recycling, and the method of the present invention can be widely applied to the phosphate-containing wastewater treatment industry.

Description

Technical Field

[0001] The invention relates to a device for treating wastewater, and in particular to a device and a process for treating wastewater containing phosphate radicals. Background Art

[0002] Small nucleic acid drugs are currently the third wave of drugs emerging in the world after small molecule drugs and antibody drugs. Small nucleic acid drugs are widely favored by the global biopharmaceutical community for their unique therapeutic effects. Driven by this trend, companies involved in the upstream raw materials and auxiliary materials of nucleosides and nucleotides, the midstream oligonucleotides, and the downstream finished products have experienced explosive development. Since small nucleic acid drugs are linked by phosphate groups, there is a problem in the upstream, midstream, and downstream, that is, a large amount of phosphate-containing wastewater will be generated. This type of wastewater has a characteristic that the phosphate content is not high but the wastewater volume is large. The "Comprehensive Sewage Discharge Standard" stipulates the discharge standards for phosphorus-containing wastewater in my country. The first-level standard: A standard: 1.0 mg / L; B standard: 1.5 mg / L; second-level standard: 3.0 mg / L; third-level standard: 5.0 mg / L; the phosphate discharge standards are as follows: first-level standard: 0.5 mg / L; second-level standard: 1.0 mg / L; no third-level standard.

[0003] Traditional phosphorus-containing wastewater treatment usually involves adding bacteria or composite phosphorus removal agents for sedimentation. The equipment is expensive and complex, the treatment cycle is long, and the footprint is large, such as Chinese patents CN106542627A, CN207121517U and CN110104821A. Summary of the invention

[0004] The purpose of the present invention is to provide a device and a process method for treating phosphate-containing wastewater. By performing primary filtration (filler adsorption) and secondary filtration (membrane adsorption) on the phosphorus-containing wastewater, the treated water can be used for recovery and even recycling. The method of the present invention can be widely used in the phosphate-containing wastewater treatment industry.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a device for treating phosphate-containing wastewater, which comprises: a precision filter, a membrane tube assembly, an electromagnetic flowmeter, a high-pressure pump and a control system; wherein the precision filter is provided with a water inlet and a water outlet, and the water inlet is used to connect the wastewater to be treated; the membrane tube assembly is composed of a plurality of parallel membrane tubes, the water inlet end of each membrane tube is connected with the water outlet of the precision filter through a pipeline, and the water outlet end of the membrane tube is used to output purified water; the high-pressure pump is arranged on the pipeline connecting the precision filter and the membrane tube, and is used to pump the wastewater to be treated into the membrane tube assembly; the electromagnetic flowmeter is arranged on the pipeline connecting the high-pressure pump and the membrane tube, and is used to monitor the water flow of the wastewater to be treated at the outlet of the high-pressure pump; the control system is connected to the electromagnetic flowmeter and the high-pressure pump through a bus, and is used to collect the flow information measured by the electromagnetic flowmeter, and regulate the high-pressure pump according to the flow information; the precision filter is filled with modified fillers; the modified fillers are sodium-based fillers or aluminum cross-linked fillers; the fillers are selected from bentonite, montmorillonite, kaolin or zeolite.

[0006] Commercially available fillers have a good effect on adsorbing solid impurities, but have a poor adsorption effect on phosphate ions. The present invention uses a modified matrix for filling to achieve a better adsorption and separation effect.

[0007] Preferably, the outer shell material of all pipelines is stainless steel 304L or 316L, and the inner lining material is polytetrafluoroethylene material.

[0008] Preferably, the number of membrane tubes arranged in parallel in the membrane tube assembly is 2 to 6, and a regulating valve is provided on the pipeline connecting the water inlet end of the membrane tube and the water outlet of the precision filter, and the regulating valve is used to control whether the membrane tube is used or not.

[0009] Preferably, the concentration membrane used in the membrane tube is selected from R / O reverse osmosis membrane or nanofiltration membrane.

[0010] Preferably, the sodium-based filler is a filler modified with sodium carbonate.

[0011] Preferably, the sodium-based filler is prepared by the following method: the raw ore is crushed and sieved to 5-100 mesh, and then fully dispersed in water, and particles with high specific gravity are agglomerated and precipitated to the bottom by gravity, and some particles are suspended in water, and a suspension is obtained by screening with a suspension screen, and the suspension is pressed to achieve preliminary separation, and the obtained solid is the purified filler; then, the purified filler is prepared into a suspension, an excess of sodium carbonate solution is added, and the mixture is stirred for 3-5 hours to perform sodiumization to obtain the sodium-based filler.

[0012] Preferably, the aluminum cross-linked filler is a filler modified by an aluminum cross-linking agent; the filler modified by the aluminum cross-linking agent is prepared by the following method: dispersing the filler in water, soaking it in a 0.3~0.8 mol / L hydrochloric acid solution, first vigorously stirring at 400 Hz for 1~4 hours, standing for 12~36 hours, performing solid-liquid separation, and then drying to obtain an acid-treated filler; titrating a 0.5~1.5 mol NaOH solution into a 0.5~1.5 mol aluminum chloride solution, stirring while titrating until the pH of the aluminum chloride solution is 6~8, to obtain an aluminum cross-linking agent; fully dispersing the acid-treated filler in water, measuring the upper suspension, dripping the cross-linking agent while stirring, vigorously stirring at 400 Hz for 1~4 hours, then standing to settle, filtering, and drying at 100°C to obtain an aluminum cross-linked adsorbent.

[0013] Another object of the present invention is to provide a process method for treating phosphate-containing wastewater, which uses the device for treating phosphate-containing wastewater to treat phosphate-containing wastewater, comprising: loading the modified filler into the precision filter by a dry method or a wet method; allowing the wastewater to enter from the water inlet of the precision filter, and sequentially undergoing primary filtration through the modified filler in the precision filter, and then undergoing secondary filtration through a membrane tube, and finally discharging the water from which the phosphate is removed from the membrane tube; and the concentrating membrane used in the membrane tube is sequentially treated with 1 mole of sodium hydroxide, deionized water, 1 mole of hydrochloric acid and deionized water for activation and regeneration.

[0014] Preferably, the sample volume of the modified filler is 1 / 4 to 2 / 3 of the volume of the precision filter.

[0015] The device and process for treating phosphate-containing wastewater of the present invention have the following advantages:

[0016] The new method and device for treating phosphate-containing wastewater of the present invention, the device performs primary filtration (filler adsorption) and secondary filtration (membrane adsorption) on the phosphorus-containing wastewater. For this industry, the treated water can be recovered or even recycled. The method of the present invention can be widely applied to the phosphate-containing wastewater treatment industry.

[0017] The present invention selects fillers that can adsorb both mechanical impurities and phosphoric acid compounds as a basis, and uses chemical methods to improve and optimize them, so that they are more targeted for adsorbing wastewater containing phosphate radicals. The present invention uses sodium salt to modify the filler. If the sewage contains free phosphoric acid, it can be fully converted into sodium phosphate salt on the filler. The filler has a better attachment effect on ionic salts, and if the device accepts compounds containing phosphoric acid for a long time, it may be corroded. The modified filler can convert the acidic phosphoric acid substance into sodium salt and become a neutral ionic compound, and the conversion into sodium salt can play a role in protecting the device.

[0018] The wastewater treatment device designed by the present invention has high treatment efficiency and can achieve a treatment capacity of 1 ton / 4h. The treated water can be recycled or discharged directly after detection. In addition, the device has the advantages of small footprint, free movement, no odor, and less solid waste (such as phosphate bentonite). The use of the device provides a new idea for the treatment of phosphorus-containing wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the device for treating phosphate-containing wastewater of the present invention. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] A device for treating wastewater containing phosphate radicals, see Figure 1 The device includes: precision filter, membrane tube assembly, electromagnetic flowmeter ( Figure 1 M), a high-pressure pump and a control system. Among them, a water inlet and a water outlet are provided on the precision filter, and the water inlet is used to connect the wastewater to be treated. The membrane tube assembly is composed of a number of membrane tubes in parallel, and the water inlet end of each membrane tube is connected to the water outlet of the precision filter through a pipeline, and the water outlet end of the membrane tube is used to output purified water. The high-pressure pump is arranged on the pipeline connecting the precision filter and the membrane tube, and is used to pump the wastewater to be treated into the membrane tube assembly. The electromagnetic flowmeter is arranged on the pipeline connecting the high-pressure pump and the membrane tube, and is used to monitor the water flow rate of the wastewater to be treated at the outlet of the high-pressure pump. The control system is connected to the electromagnetic flowmeter and the high-pressure pump through a bus, and is used to collect the flow information measured by the electromagnetic flowmeter, and regulate the high-pressure pump according to the flow information.

[0022] The outer shell material of all pipelines from the liquid inlet to the liquid outlet is stainless steel 304L or 316L, and the inner lining material is polytetrafluoroethylene. If 304L stainless steel is used, its corrosion resistance is poor. Before use, the whole device can be passivated for 0.5~1.0h with 0.5~1.0 molar hydrochloric acid solution without membrane.

[0023] The number of membrane tubes arranged in parallel in the above-mentioned membrane tube assembly is 2 to 6. An artificial regulating valve is provided on the pipeline connecting the water inlet end of the membrane tube with the water outlet of the precision filter. The switch can be adjusted according to demand to control whether the membrane tube is used or not.

[0024] The concentration membrane used in the above membrane tube is selected from R / O reverse osmosis membrane or nanofiltration membrane. After the R / O reverse osmosis membrane reaches saturation, it can be activated and regenerated by treating it in sequence of 1 mole of sodium hydroxide-deionized water-1 mole of hydrochloric acid-deionized water, and can be used for 6 to 10 times after regeneration.

[0025] The precision filter is filled with a modified filler. The filler is selected from bentonite, montmorillonite, kaolin or zeolite. The modified filler is a sodium-based filler or an aluminum cross-linked filler, wherein the sodium-based filler is a filler modified by sodium carbonate. The aluminum cross-linked filler is a filler modified by an aluminum cross-linking agent.

[0026] Specifically, the preparation method of the sodium-based filler comprises:

[0027] After the raw ore is crushed and sieved to 5-100 mesh (preferably 50 mesh), it is fully dispersed in water. The particles with higher specific gravity agglomerate and sink to the bottom by gravity, and some particles are suspended in water. The suspension is screened through a suspension screen and pressed dry to achieve preliminary separation. The solid obtained is the purified filler. Then, the purified filler is prepared into a suspension, and an excess of sodium carbonate solution is added. Stir for 3-5 hours to obtain sodium-based fillers, such as sodium soil (i.e. sodium-based bentonite). Finally, the modified filler after screening is passed through a 5-100 mesh sieve and wet-loaded.

[0028] Wherein, the above-mentioned raw ore is selected from bentonite, montmorillonite, kaolin or zeolite raw ore.

[0029] Specifically, the preparation method of aluminum cross-linked filler comprises:

[0030] Disperse commercially available bentonite in distilled water, soak it in 0.3-0.8 mol / L hydrochloric acid solution, place it on a magnetic stirrer for strong stirring for 1-4 hours, let it stand for 12-36 hours, separate the solid and liquid, and then place the bentonite in an oven to dry for later use;

[0031] Titrate 0.5~1.5 mole NaOH solution into 0.5~1.5 mole aluminum chloride solution, stirring while titrating, until the pH of the aluminum chloride solution is 6~8, to obtain an aluminum crosslinking agent. The newly prepared crosslinking agent can be stored at a low temperature of 2~8 degrees and can be used in subsequent crosslinking;

[0032] Weigh a certain amount of the above-treated bentonite and fully disperse it in water, measure the upper suspension, drop the cross-linking agent into it while stirring until the mixed solution becomes turbid, then let it stand to settle, filter it, and dry it at 100°C to obtain the aluminum cross-linked adsorbent.

[0033] During the research, although it is simple and quick to directly use unmodified fillers for dry or wet filling (add 3 volumes of purified water slurry for wet filling), the phosphorus removal effect is lower than that of modified fillers when compared with the phosphorus removal effect of modified fillers by wet filling.

[0034] The following describes the application of the device for treating phosphate-containing wastewater provided by the present invention in specific wastewater treatment through application examples.

[0035] Application Example 1

[0036] The device of the present invention is used to treat 1 ton of wastewater with an initial phosphate concentration of 20.8 mg / L.

[0037] The sodium bentonite is wet loaded, and the loading volume is 1 / 2 of the volume of the precision filter. The wastewater enters from the water inlet of the precision filter, and is filtered through the filler of the precision filter in turn for the first level, and then through 3 membrane tubes for the second level, and finally the water with phosphate removed is discharged from the membrane tube.

[0038] The preparation method of the above sodium bentonite is:

[0039] The commercial bentonite is crushed and sieved to 50 mesh, fully dispersed in water, and separated and purified from impurity minerals such as muscovite, quartz, zeolite, etc. with larger particle size or specific gravity. Then, the purified bentonite is prepared into a suspension, and a sodium carbonate solution with an excess of 5-10% mass fraction relative to the purified bentonite is added, stirred for 3-5 hours, and sodiumized to obtain sodium soil, which is passed through a 50-mesh sieve, and the sieved modified sodium bentonite is wet-filled.

[0040] It was determined that the removal rate of phosphate after primary filtration was 84%, and the removal rate of phosphate after secondary filtration was 100%.

[0041] Application Example 2

[0042] It is basically the same as Application Example 1, except that the filler used is aluminum cross-linked bentonite.

[0043] The preparation method of the above aluminum cross-linked bentonite is:

[0044] Disperse commercially available bentonite in distilled water, soak it in 0.3~0.8 mol / L hydrochloric acid solution, place it on a magnetic stirrer and stir it vigorously for 1~4 hours, let it stand for 12~36 hours, then perform solid-liquid separation, and then place the bentonite in an oven to dry for later use.

[0045] Titrate the prepared 0.5-1.5 molar NaOH solution into the 0.5-1.5 molar aluminum chloride solution, stirring while titrating until the pH of the aluminum chloride solution is 6-8. Leave the prepared aluminum crosslinking agent at room temperature for three weeks for use.

[0046] Weigh a certain amount of sodium bentonite and fully disperse it in water. Measure the upper suspension and drip the aluminum crosslinking agent while stirring until the mixed solution becomes turbid. Then let it stand for sedimentation, filter it, and dry it at 100°C to obtain aluminum crosslinked bentonite.

[0047] The modified bentonite is wet packed.

[0048] It has been determined that the removal rate of phosphate after primary filtration is 85%, and the removal rate of phosphate after secondary filtration is 100%.

[0049] Application Example 3

[0050] It is basically the same as Application Example 2, except that the sample volume is 1 / 4 of that of the precision filter device.

[0051] It was determined that the removal rate of phosphate after primary filtration was 88%, and the removal rate of phosphate after secondary filtration was 100%.

[0052] Comparative Example 1

[0053] It is basically the same as Application Example 1, except that the filler used is untreated bentonite.

[0054] It was determined that the removal rate of phosphate after primary filtration was 55%, and the removal rate of phosphate after secondary filtration was 69%.

[0055] Comparative Example 2

[0056] It is basically the same as Comparative Example 1, except that the sample volume is 2 / 3 of the volume of the precision filter.

[0057] It was determined that the removal rate of phosphate after primary filtration was 52%, and the removal rate of phosphate after secondary filtration was 79%.

[0058] Comparative Example 3

[0059] It is basically the same as Application Example 1, except that: the device used only has the membrane tube component of the device of the present invention, and there is no precision filter as the first-level filtration, and it does not pass through the first-level filtration, but only passes through the membrane tube component.

[0060] It was determined that the removal rate of phosphate in phosphorus-containing wastewater by the device of comparative example 3 was 43%. Compared with application example 1, the removal rate of phosphorus was significantly lower, which shows that without the adsorption effect of the matrix, the adsorption efficiency of the membrane tube alone is far lower than the two-stage purification efficiency.

[0061] Comparative Example 4

[0062] It is basically the same as Application Example 2, except that: the device used only has the precision filter of the device of the present invention as the primary filtration, there is no membrane tube assembly, and no secondary filtration is performed.

[0063] It was determined that the removal rate of phosphate in phosphorus-containing wastewater after the device of comparative example 4 was 75%. Compared with application example 2, the removal rate of phosphorus was significantly reduced. It can be seen that without the secondary adsorption effect, it is difficult to completely adsorb the impurity phosphorus by relying on a simple primary adsorption, and there is a synergistic effect between the two-stage filtration, and the secondary filtration increases the removal rate of the primary filtration.

[0064] Table 1 shows the removal rate of phosphate in each application example and comparative example.

[0065]

[0066] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A device for treating phosphate-containing wastewater, characterized in that: The device includes: precision filter, membrane tube assembly, electromagnetic flowmeter, high-pressure pump and control system; Wherein, the precision filter is provided with a water inlet and a water outlet, and the water inlet is used to receive the wastewater to be treated; The membrane tube assembly is composed of a plurality of membrane tubes connected in parallel, the water inlet end of each membrane tube is connected to the water outlet of the precision filter through a pipeline, and the water outlet end of the membrane tube is used to output purified water; The high-pressure pump is arranged on a pipeline connecting the precision filter and the membrane tube, and is used to pump the wastewater to be treated into the membrane tube assembly; The electromagnetic flowmeter is arranged on the pipeline connecting the high-pressure pump and the membrane tube, and is used to monitor the water flow of the wastewater to be treated at the outlet of the high-pressure pump; The control system is connected to the electromagnetic flowmeter and the high-pressure pump through a bus, and is used to collect flow information measured by the electromagnetic flowmeter and regulate the high-pressure pump according to the flow information; The precision filter is filled with a modified filler; the modified filler is a sodium-based filler or an aluminum cross-linked filler; the filler is selected from bentonite, montmorillonite, kaolin or zeolite; The concentration membrane used in the membrane tube is selected from R / O reverse osmosis membrane or nanofiltration membrane; The sodium-based filler is a filler modified by sodium carbonate; the sodium-based filler is prepared by the following method: After the raw ore is crushed and sieved to 5-100 mesh, it is fully dispersed in water. The particles with higher specific gravity agglomerate and sink to the bottom by gravity, while some particles are suspended in water. The suspension is screened by a suspension screen and squeezed to achieve preliminary separation. The solid obtained is the purified filler; Then, the purified filler is prepared into a suspension, an excess of sodium carbonate solution is added, and the mixture is stirred for 3 to 5 hours to obtain a sodium-based filler; The aluminum cross-linked filler is a filler modified by an aluminum cross-linking agent; the aluminum cross-linking agent-modified filler is prepared by the following method: The filler is dispersed in water, soaked in a 0.3-0.8 mol / L hydrochloric acid solution, stirred vigorously at 400 Hz for 1-4 hours, allowed to stand for 12-36 hours, then solid-liquid separation is performed, and then dried to obtain an acid-treated filler; Titrate 0.5-1.5 mol NaOH solution into 0.5-1.5 mol aluminum chloride solution, stirring while titrating, until the pH of the aluminum chloride solution reaches 6-8, to obtain an aluminum crosslinking agent; The acid-treated filler is fully dispersed in water, the upper suspension is measured, and the cross-linking agent is dripped into the suspension while stirring. The suspension is vigorously stirred at 400 Hz for 1 to 4 hours, and then allowed to settle, filtered, and dried at 100° C. to obtain an aluminum cross-linked adsorbent.

2. The device for treating phosphate-containing wastewater according to claim 1, characterized in that: The outer shell material of all pipelines is stainless steel 304L or 316L, and the lining material is polytetrafluoroethylene.

3. The device for treating phosphate-containing wastewater according to claim 1, characterized in that: The number of membrane tubes arranged in parallel in the membrane tube assembly is 2 to 6, and a regulating valve is provided on the pipeline connecting the water inlet end of the membrane tube and the water outlet of the precision filter, and the regulating valve is used to control whether the membrane tube is used or not.

4. A process for treating phosphate-containing wastewater, characterized in that: The process method uses the device for treating phosphate-containing wastewater as described in any one of claims 1 to 3 to treat phosphate-containing wastewater, comprising: Filling the modified filler into the precision filter by dry method or wet method; The wastewater enters the water inlet of the precision filter, is filtered through the modified filler in the precision filter, and then filtered through the membrane tube for the second stage, and finally the water with phosphate removed is discharged from the membrane tube; The concentrated membrane used in the membrane tube is activated and regenerated by treating with 1 molar sodium hydroxide, deionized water, 1 molar hydrochloric acid and deionized water in sequence.

5. The process according to claim 4, characterized in that: The sample loading volume of the modified filler is 1 / 4 to 2 / 3 of the volume of the precision filter.

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