Coagulation / ferrate oxidation interaction enhancement-ultrafiltration integrated device for drinking water treatment and application technology thereof

Abstract

The invention belongs to the technical field of environmental protection and water treatment, and particularly discloses a coagulation / ferrate oxidation interaction strengthening-ultrafiltration integrated device for drinking water treatment and an application technology of the coagulation / ferrate oxidation interaction strengthening-ultrafiltration integrated device. The effect of removing suspended matters, colloidal particles, soluble organic matters and new pollutants in water is synchronously enhanced, the water quality safety of the drinking water can be effectively guaranteed, the pollution of the ultrafiltration membrane is relieved, and the treatment cost of the drinking water is reduced. The integrated equipment also has the characteristics of small occupied area, simple structure and the like, can reduce the occupied area and the corresponding construction cost, and has important significance on the construction of future drinking water treatment engineering.

Description

Technical Field

[0001] The invention relates to a coagulation / ferrate oxidation mutual enhancement-ultrafiltration integrated device for drinking water treatment and an application technology thereof, belonging to the technical field of environmental protection and water treatment. Background Art

[0002] At present, most drinking water plants still use the traditional coagulation-sedimentation-filtration-disinfection process, which has effectively ensured the safety of drinking water quality in the past few decades. However, facing the challenges of modern water treatment, traditional processes have gradually exposed some limitations. First, the traditional water treatment process is long, the water treatment structure occupies a large area, the operation process consumes high energy and has high operating costs. Secondly, with the development of industrialization and the intensification of agricultural activities, the concentration of new pollutants in water sources is gradually increasing, and most of them do not have corresponding drinking water standards. Although these new pollutants are basically all at the ng / L level in drinking water sources. However, considering that the traditional water treatment process has extremely limited removal effect on these new pollutants, as these new pollutants further accumulate in drinking water sources, the potential drinking water safety risks caused by them are still gradually increasing. In summary, although the traditional water treatment process can still meet the basic requirements of current drinking water, with the demand for energy saving and consumption reduction in water treatment and the changes in the characteristics of pollutants in water, it is urgent to develop and reserve more advanced water treatment technologies to provide new technical guarantees for drinking water treatment.

[0003] At present, technologies such as coagulation, oxidation and ultrafiltration have been widely used in drinking water treatment. However, these methods are targeted at removing some pollutants in water, and their individual application still has certain defects. For example, coagulation can usually effectively remove colloids and suspended matter in water, but the effect on the removal of soluble organic matter in water is extremely limited; although oxidation can effectively degrade and remove soluble organic matter in water, it may also lead to problems such as the generation of toxic byproducts and increased energy consumption; although ultrafiltration technology performs well in removing suspended matter, colloids and macromolecular organic matter, the membrane fouling problem is more serious when it is used alone. Therefore, the above technologies usually need to be combined into a set of process flows to solve the defects that exist when a single technology is applied.

[0004] In recent years, short-process water treatment technology with ultrafiltration as the core has gradually emerged. Usually, coagulation, oxidation and adsorption technologies are coupled with ultrafiltration, which can significantly improve the removal effect of various pollutants such as particulate matter and dissolved organic matter in water, while effectively slowing down membrane pollution, thereby achieving multiple goals such as intensive water treatment structures, reduced treatment energy consumption and improved pollutant removal efficiency. However, the current short-process water treatment technology with membrane filtration as the core still has certain shortcomings. For example, the invention patent CN114249453A coagulation-sedimentation-ultrafiltration integrated device integrates three water treatment processes of coagulation, sedimentation and ultrafiltration into one, simplifies the treatment process, reduces equipment and construction costs, but still does not solve the potential safety risks caused by various new pollutants in water. Patent CN212669374U is a multi-stage activated carbon adsorption and ultrafiltration membrane combined drinking water treatment device, which can effectively filter chlorine, chemical toxins, pesticides, heavy metals, etc. in water to ensure the quality of drinking water. However, problems such as activated carbon regeneration, microbial growth on the surface of activated carbon for a long time and disposal of waste activated carbon still need to be considered. Patent CN104773886B discloses a method for removing dissolved organic matter from drinking water by combining titanium dioxide photocatalytic oxidation and ultrafiltration, which can effectively reduce membrane pollution by degrading dissolved organic matter in water. However, it still faces problems such as by-product generation and difficulty in removing particulate matter during its application. In summary, how to achieve the simultaneous removal of particulate matter, dissolved organic matter and new pollutants in water while maintaining its intensive and low energy consumption characteristics through short-process water treatment technology with ultrafiltration as the core is still a major problem in the field of drinking water treatment.

[0005] Based on the above background, the present invention proposes a coagulation / ferrate oxidation mutual enhancement-ultrafiltration integrated device for drinking water treatment and its application technology based on the unique mutual enhancement effect of coagulation and ferrate oxidation found in previous studies. This technology innovatively utilizes the interaction between coagulation and ferrate oxidation to achieve efficient drinking water treatment. Specifically, coagulation can effectively remove particulate matter and large molecular hydrophobic organic matter in the water, and remove the interference of the above pollutants for ferrate oxidation, so that it can more efficiently oxidize small molecular hydrophilic organic matter and new pollutants in the water. At the same time, the new ecological iron generated by the ferrate oxidation reaction can not only adsorb new pollutants, but also serve as the flocculation core to enhance the growth of flocs in the coagulation process, improve the sedimentation performance of colloids and suspended matter in water, and simultaneously reduce ultrafiltration membrane pollution. The interactive reinforcement effect of coagulation and oxidation makes the removal of various pollutants in the water treatment process more comprehensive and efficient. It can not only remove suspended matter and colloidal particles in the water, but also remove soluble organic matter and new pollutants. It can effectively reduce ultrafiltration membrane pollution while improving the effluent quality, and simultaneously ensure the safety of drinking water and reduce operating costs. It is of great significance for the construction of future drinking water treatment projects. Summary of the invention

[0006] A coagulation / ferrate oxidation interactive enhancement-ultrafiltration integrated device for drinking water treatment and its application technology

[0007] The technical solution of the present invention is as follows:

[0008] A coagulation / ferrate oxidation mutual enhancement-ultrafiltration integrated device for drinking water treatment, characterized in that: coagulation reaction, ferrate oxidation reaction and ultrafiltration can occur in the same reactor. By utilizing the unique mutual enhancement effect of coagulation and ferrate oxidation, the coagulation / ferrate oxidation-ultrafiltration integrated device can increase the membrane flux by 25 times and has a significant effect on DOC and UV. 254 The removal rates of ibuprofen (IBP) and 2,4-dichlorophenoxyacetic acid (2,4-D) were as high as 75.00% and 85.00% respectively, and the removal rates of ibuprofen (IBP) and 2,4-dichlorophenoxyacetic acid (2,4-D) were even higher, reaching 95.00% and 93.00%.

[0009] As a further solution of the present invention, the unique interactive strengthening effect of coagulation and ferrate oxidation means that coagulation can effectively remove particulate matter and large molecular hydrophobic organic matter in water, and remove the interference of the above pollutants for ferrate oxidation, so that it can more efficiently oxidize small molecular hydrophilic organic matter and new pollutants in water. At the same time, the new ecological iron generated by the ferrate oxidation reaction can not only adsorb new pollutants, but also serve as a flocculation core to strengthen the growth of flocs in the coagulation process, improve the sedimentation performance of colloids and suspended matter in water, and simultaneously reduce ultrafiltration membrane pollution.

[0010] The coagulation reaction is characterized in that: the type of coagulant added is polyaluminium chloride with a B value of 2.0, and the addition amount is 30mg / L; the ferrate oxidation reaction is characterized in that: potassium ferrate (K2FeO4) is added, and the addition amount is 30mg / L, the oxidation time is 60min, and the stirring speed is 50rpm; coagulation / ferrate oxidation can remove DOC to 60% and remove UV 254 To 83.00%; the ultrafiltration is characterized in that: negative pressure is used to drive the liquid through the ultrafiltration membrane for filtration, and the membrane material used in the ultrafiltration is polyvinylidene fluoride (PVDF).

[0011] The coagulation / ferrate oxidation mutual enhancement-ultrafiltration integrated device for drinking water treatment described in the present invention has the following operating steps:

[0012] (1) Add polyaluminium chloride with a B value of 2.0 into water and stir it thoroughly with a frame mixer. The addition amount is 30 mg / L.

[0013] (2) While the coagulation reaction is taking place, ferrate is added to the water. When the concentration of natural organic matter (NOM) is less than 5 mg / L, 20 mg / L K2FeO4 is added, and the oxidation time is 30 minutes. DOC and UV 254 The removal rates of DOC and UV were 69.00% and 78.00% respectively, and the removal rates of IBP and 2,4-D were 85.00% and 83.00% respectively. When the NOM concentration was greater than 5 mg / L, the ferrate dosage was increased to 30 mg / L, the reaction time was 60 minutes, and the removal rates of DOC and UV 254 The removal efficiencies of were 72.00% and 80.00%, and the removal efficiencies of IBP and 2,4-D were 95.00% and 93.00%, respectively.

[0014] (3) The water after the coagulation / ferrate oxidation cross-enhancement reaction is ultrafiltered in situ by negative pressure drive, and the effluent is disinfected for subsequent use. 254 The removal rates were as high as 75.00% and 85.00% respectively.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The interactive enhancement effect of coagulation and ferrate is used to simultaneously enhance the removal of suspended solids, colloidal particles, dissolved organic matter and new pollutants in water, effectively ensuring the safety of drinking water quality;

[0017] 2. The integrated equipment occupies a small area and has a simple structure, reducing the floor space and construction costs;

[0018] 3. Effectively reduce ultrafiltration membrane pollution, reduce maintenance frequency, extend the service life of membrane components, and reduce operating and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The invention discloses a coagulation / ferrate oxidation mutual enhancement-ultrafiltration integrated device for drinking water treatment, wherein 1 is a water inlet pipe; 2 is a coagulant addition port; 3 is an oxidant addition port; 4 is a mixer; 5 is a stirring paddle; 6 is a water outlet pipe; 7 is a backwash pipe; 8 is a vent pipe; 9 is an overflow pipe; 10 is an ultrafiltration membrane; and 11 is a backwash device. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to specific implementation cases:

[0021] Example 1

[0022] This embodiment is realized through a small test, and the coagulant uses PACl with a B value of 2.0. The specific process is to add PACl coagulant to the raw water to carry out a coagulation ferrate oxidation interaction experiment, wherein the coagulation stirring intensity is 100rpm, and ferrate (K2FeO4) is added simultaneously for oxidation experiment, and its addition amount is 30mg / L, the oxidation reaction time is set to 60 minutes, and the stirring speed is 100rpm. After the pretreatment is completed, the ultrafiltration experiment is immediately carried out, and then the coagulation oxidation ultrafiltration effluent is tested and analyzed to achieve UV 254 , DOC and new pollutants are removed simultaneously. Under the best conditions, DOC and UV 254 The removal rates of can be increased to 75.00% and 85.00%, and the removal rates of IBP and 2,4-D can reach 95.00% and 93.00%.

[0023] Example 2

[0024] This example uses a pilot scale experiment in a water plant. The specific process is as follows: First, the water sample of the water plant is coagulated and oxidized in a coagulation / ferrate oxidation interactive enhancement-ultrafiltration integrated device, and then the treated effluent is filtered through an ultrafiltration device to achieve DOC, UV 254 The coagulant is PACl, the oxidant is K2FeO4, and the ultrafiltration membrane is made of polyvinylidene fluoride (PVDF).

[0025] After taking the experimental water sample from the water plant, adjust the stirrer speed, add an appropriate amount of aluminum chloride solution, and simultaneously add a certain amount of ferrate solid powder for rapid stirring for 1 minute, followed by slow stirring at 50rpm for 60 minutes to complete the coagulation and ferrate oxidation interactive enhancement experiment, where the oxidation time and dosage are set according to the NOM content of the water sample from the water plant. The water after coagulation and ferrate oxidation is ultrafiltered in situ.

[0026] Through the coagulation / ferrate oxidation-ultrafiltration process, organic matter with a molecular weight of 10kDa and 1-4kDa can be removed efficiently. After using this process, the membrane flux increased by 25 times, DOC and UV 254 The removal rates of ferrate-oxidation and coagulation were 77.00% and 84.00%, respectively, while the removal rates of IBP and 2,4-D were 94.00% and 95.00%, respectively. In addition, the water plant calculations have verified that the coagulation / ferrate oxidation interactive enhancement-ultrafiltration integrated device has a small footprint and a simple structure, which can effectively reduce the land occupation and construction costs, while removing suspended solids, colloidal pollutants, dissolved organic matter and new pollutants, which helps to slow down the pollution of ultrafiltration membranes and reduce operation and maintenance costs.

[0027] The specific embodiments described above are only preferred implementations of the present invention, but other aspects and implementations will be obvious to those skilled in the art. Several modifications and improvements may be made without departing from the principles of the present invention, all of which fall within the scope of protection of this application.

Claims

1. A coagulation / ferrate oxidation cross-enhancement-ultrafiltration integrated device for drinking water treatment, characterized in that: In the same reactor, coagulation reaction, ferrate oxidation reaction and ultrafiltration can occur. By utilizing the unique interaction between coagulation and ferrate oxidation, the coagulation / ferrate oxidation-ultrafiltration integrated device can increase the membrane flux by 25 times and has a significant impact on DOC and UV. 254 The removal rates of ibuprofen (IBP) and 2,4-dichlorophenoxyacetic acid (2,4-D) were as high as 75.00% and 85.00% respectively, and the removal rates of ibuprofen (IBP) and 2,4-dichlorophenoxyacetic acid (2,4-D) were even higher, reaching 95.00% and 93.00%.

2. The unique interactive reinforcement effect of coagulation and ferrate oxidation described in claim 1 means that coagulation can effectively remove particulate matter and large molecular hydrophobic organic matter in water, remove the interference of the above pollutants for ferrate oxidation, and enable it to more efficiently oxidize small molecular hydrophilic organic matter and new pollutants in water. At the same time, the new ecological iron generated by the ferrate oxidation reaction can not only adsorb new pollutants, but also serve as a flocculation core to enhance the growth of flocs in the coagulation process, improve the sedimentation performance of colloids and suspended matter in water, and simultaneously reduce ultrafiltration membrane pollution.

3. The coagulation reaction according to claim 1, characterized in that: The type of coagulant added is polyaluminium chloride with a B value of 2.0, and the dosage is 30 mg / L.

4. The ferrate oxidation reaction according to claim 1, characterized in that: Potassium ferrate (K2FeO4) was added at a dosage of 30 mg / L, the oxidation time was 60 min, and the stirring speed was 50 rpm; coagulation / ferrate oxidation can remove DOC to 60% and remove UV 254 To 83.00%.

5. The ultrafiltration according to claim 1, characterized in that: Negative pressure is used to drive the liquid through the ultrafiltration membrane for filtration. The membrane material used in ultrafiltration is polyvinylidene fluoride (PVDF).

6. A coagulation / ferrate oxidation cross-enhancement-ultrafiltration integrated device for drinking water treatment according to claims 1-5, wherein the operating steps are as follows: (1) Add polyaluminium chloride with a B value of 2.0 into the water for coagulation reaction, and stir it thoroughly with a frame mixer. The addition amount is 30 mg / L. (2) While the coagulation reaction is taking place, ferrate is added to the water. When the concentration of natural organic matter (NOM) is less than 5 mg / L, 20 mg / L K2FeO4 is added and the oxidation time is 30 minutes; when the NOM concentration is greater than 5 mg / L, the ferrate dosage is increased to 30 mg / L and the reaction time is 60 minutes. (3) The water after the coagulation / ferrate oxidation cross-enhanced reaction is ultrafiltered in situ by negative pressure drive, and the effluent is disinfected for subsequent use.

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