LU505018B1

LU505018B1 - Method and device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid

Info

Publication number: LU505018B1
Application number: LU505018A
Authority: LU
Inventors: Xueli Hu; Jiabo Chen; Shutao Lin; Xinyu Cao; Yongheng Zhang; Yun Bai; Ping Xiang
Original assignee: Univ Chongqing
Priority date: 2023-08-29
Filing date: 2023-08-29
Publication date: 2024-02-29

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a method and a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid. A large number of cavitation bubbles can be generated by ultrasonic radiation, and the huge energy generated by the collapse of cavitation bubbles can destroy microbial cell walls and cell membranes, and can disperse pathogen cell aggregates attached to solid impurities into a single cell state, so that the resistance of cells to chemical disinfectants is reduced, which is beneficial to further inactivation of chemical disinfectants. After ultrasonic irradiation, the bacterial cells of pathogenic bacteria are in a single-cell dispersed state, and the protective effect of bacterial micelle is effectively reduced. Peroxyacetic acid can enter the cell and act on intracellular substances to further inactivate pathogenic bacteria through directly passing the damaged cell membrane, or through the molecular diffusion.

Description

DESCRIPTION LU505018

METHOD AND DEVICE FOR INACTIVATING PATHOGENIC

MICROORGANISMS IN WATER BY ACOUSTIC WAVE ENHANCED PERACETIC

ACID

TECHNICAL FIELD

The invention relates to the technical field of wastewater treatment, in particular to a method and a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid.

BACKGROUND

The problem of water pollution caused by pathogenic microorganisms is becoming more and more serious, which has attracted worldwide attention. Especially, when sudden pathogens spread wildly over a short period of time, a large number of sewages containing high concentration of pathogenic microorganisms might cause adverse effect on the traditional sewage treatment process. Disinfection of water body is the key to prevent the outbreak of pathogenic bacteria and ensure public health. However, traditional disinfection technologies (chlorine, ozone, sodium hypochlorite, hydrogen peroxide and ultraviolet) not only are difficult to deal with the sudden water pollution caused by pathogenic bacteria, but also produce a variety of disinfection by-products (DBPs), thereby posing a serious threat to the ecological environment and public safety. At present, efficient and environmentally friendly disinfection technology is urgently required to deal with the sudden water pollution caused by pathogenic microorganisms.

Ultrasonic wave refers to sound wave with frequency of 20 kHz or above, with short wave length, good directivity and strong penetration. According to the ultrasonic frequency, ultrasound can be divided into low-frequency ultrasound (20-100kHz) and high-frequency ultrasound (>100kHz). For low-frequency ultrasound (<100kHz, usually 20-48kHz), the key sterilization mechanism involves mechanical shock, which leads to the mechanical destruction of bacterial cell membrane. Compared with low-frequency ultrasound, high-frequency ultrasound (>100kHz) has stronger inactivation ability to pathogenic microorganisms in aqueous solution. High frequency ultrasound can produce cavitation bubbles. These microbubbles can inactivaté}505018 enzymes and destroy cell membrane, DNA, RNA and protein by producing physical and chemical effects, thus achieving the purpose of inactivating pathogenic microorganisms.

Peroxyacetic acid is an organic peroxide and broad-spectrum antibacterial agent, which is synthesized by the reaction of acetic acid with hydrogen peroxide (H,O) in the presence of sulfuric acid and other catalysts. Peroxyacetic acid is a strong oxidant with a high standard reduction potential (1.96V), which is close to HO; and higher than chlorine. Peroxyacetic acid has been widely used in sewage disinfection, pollutant degradation, pulp and paper industry and other fields. Compared with some traditional disinfectants, peracetic acid has many advantages in inactivating pathogenic microorganisms, including excellent bactericidal ability, strong operability and limited DBPs in treated effluent. Therefore, peracetic acid could be a promising substitute for chlorinated disinfectants to achieve a rapid disinfection in the sudden pathogen water pollution event. However, peracetic acid still has some problems. Firstly, a large amount of acetic acid produced by the self-decomposition of peracetic acid will provide a carbon source for the resurrection of pathogenic bacteria, which will increase the risk of pathogen re-growth.

Secondly, adding peracetic acid catalysts such as Cu”*, Ag’ and Co** will cause secondary pollution to water. Therefore, PAA combined with ultrasound could be an alternative to enhance disinfection and reduce the regrowth of pathogens in wastewater.

SUMMARY

The purpose of the invention is to provide a method and a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, so as to solve the problems existing in the prior art.

In order to achieve the above purpose, the invention provides a method and a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, comprising the following steps: removing insoluble impurities in sewage by precipitation; carrying out ultrasonic radiation treatment on sewage, wherein the ultrasonic radiation treatment at least comprises two different ultrasonic frequencies. When sewage is treated by ultrasonic radiation with different frequencies, the agglomerated pathogenic microorganisms hHU505018 the water are dispersed into single cell state, the cell membrane is destroyed, and the resistance of pathogenic microorganisms to chemical disinfectants is obviously reduced.

Adding strong oxidant into the sewage treated by ultrasonic radiation to further inactivate pathogenic microorganisms in the sewage, wherein the strong oxidant is peracetic acid solution.

Peracetic acid enters cells by molecular diffusion or directly penetrate damaged cell membranes to oxidize substances in cells, and further inactivates pathogenic microorganisms in water.

Optionally, the ultrasonic radiation treatment further comprises: arranging low-frequency ultrasonic probe below the sewage level, arranging high-frequency ultrasonic transducer at the bottom of the sewage.

Optionally, the precipitation time is not less than 10 min.

Optionally, the ultrasonic radiation treatment time is not less than 10 min.

Optionally, the ultrasonic radiation treatment further comprises: outputting a sinusoidal signal for conversion into ultrasonic waves by an ultrasonic generator, wherein the power density of the ultrasonic generator is not lower than 0.038W/mL.

Optionally, the ultrasonic radiation treatment further comprises: arranging the low-frequency ultrasonic probe 2 cm below the sewage level.

Optionally, the concentration of peracetic acid in sewage is not less than 26 um.

Optionally, the mass fraction of peracetic acid in the peracetic acid solution is not less than 18.04%.

The invention provides a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, sequentially comprising a sewage inlet area, an ultrasonic radiation area and a peracetic acid reaction area.

The sewage inlet area is provided with a water inlet pipe, a flow retarder, a bypass pipe, a circular gate I and a circular gate II. The circular gate I is installed on the water inlet pipe. The bypass pipe is arranged at the bottom of the sewage inlet area, and the circular gate II is installed on the bypass pipe. When the gate and ram are damaged and the equipment need to be maintained, the water in the intake area can be discharged through the bypass pipe. Meanwhile, when the inlet water quality is good and does not need to be treated, the inlet water can be directly discharged from the bypass pipe, and the flow retarder is used to ensure the stability 68505018 the water flow speed,

An ultrasonic radiation area is provided with a drain pipe, a butterfly valve, an ultrasonic transducer, a power distribution cabinet, an ultrasonic generator and a water level monitor. The butterfly valve is installed on the drainage pipe. The ultrasonic generator can convert the commercial power into alternating current signals to matched with the ultrasonic transducer. The ultrasonic transducer can generate at least three different ultrasonic frequencies (60 kHz, 430 kHz and 1120 kHz). When the ultrasonic equipment fails, the sewage in the ultrasonic radiation area can be discharged through the drain pipe at the bottom for quick maintenance.

A flashboard is arranged between the sewage inlet area and the ultrasonic radiation area for controlling water flow.

The peracetic acid reaction zone is provided with a water level controller, an automatic dosing box, a stirrer and a water outlet pipe, and a circular gate III. The circular gate III is installed on the water outlet pipe. The stirrer is used for fully mixing the peracetic acid solution and sewage in the reaction zone, and the automatic dosing box is used for dosing the peracetic acid solution with appropriate concentration into the reaction zone.

A hydraulic controller and a power distribution cabinet connected with the hydraulic controller are arranged between the ultrasonic radiation zone and the peracetic acid reaction zone, and the water level controller in the peracetic acid reaction zone and the water level monitor in the ultrasonic radiation zone are both electrically connected with the hydraulic controller.

Compared with the prior art, the invention has the following advantages and technical effects. 1. Ultrasound and peracetic acid have excellent synergistic bactericidal effect. Ultrasonic radiation can produce a large number of cavitation bubbles, and the huge energy generated by the collapse of cavitation bubbles is enough to cause water molecules (radiation decomposition) to split into hydroxyl radicals (OH-) and hydrogen atoms (He). Highly active OHe inactivate pathogenic microorganisms by attacking microbial cell walls and cell membranes. The rupture of cavitation bubbles also could cause several physical effects, including huge shear forceV505018 instantaneous high temperature and high pressure, which could disperse pathogen cell aggregates into single-cell state through directly acting on the cell structure. These physical effects would decrease the resistance of cells to chemical disinfectants and further enhance inactivation of chemical disinfectants. On the other hand, ultrasonic radiation can effectively destroy the cell membrane of pathogenic bacteria, which is conducive to the direct diffusion of peracetic acid into cells through damaged cell membranes or molecules, and act on intracellular substances to further inactivate pathogenic bacteria. 2. The synergistic sterilization technology of ultrasound and peracetic acid can effectively reduce the energy consumption and time cost of ultrasonic sterilization alone, which provides technical reference for the large-scale and wide-range application of ultrasonic sterilization. At the same time, ultrasonic and peracetic acid sterilization technology produce limited disinfection by-products, which is an efficient and environmentally friendly disinfection technology. 3. The ultrasonic enhanced peracetic acid disinfection device can be resized to adapt to the inactivation of pathogens in different wastewater, such as hospital wastewater, domestic wastewater and aquaculture wastewater. Ideally, the device can be manually moved to different locations, such as houses, commercial buildings, hospitals, warehouses and sewage treatment plants, to achieve rapid disinfection of different wastewater. The integrated device can greatly reduce the risk of water disease, and effectively avoid the problems of toxic by-products and high energy consumption in the traditional disinfection method.

BRIEF DESCRIPTION OF THE FIGURES

In order to explain the embodiments of the present invention or the technical scheme in the prior art more clearly, the drawings needed in the embodiments will be briefly introduced below.

Obviously, the drawings described below are only some embodiments of the present invention, and other drawings can be obtained according to these drawings without creative work for ordinary people in the field.

Fig. 1 is a schematic diagram of a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid;

Fig. 2 is a top view of the device for inactivating pathogenic microorganisms in water 4505018 acoustic wave enhanced peracetic acid;

Fig. 3 is a cross-sectional view of a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid;

Fig. 4 shows the effect of ultrasonic enhanced peracetic acid treatment on the cell morphology of Escherichia coli;

Fig. 5 shows the effects of ultrasonic alone, peracetic acid alone and ultrasonic enhanced peracetic acid treatment on protein of Escherichia coli in water,

Fig. 6 shows the effect of pH on inactivation of Escherichia coli in water by ultrasound enhanced peracetic acid treatment;

Fig. 7 shows the effect of the temperature on inactivation of Escherichia coli in water by ultrasound enhanced peracetic acid treatment;

Fig. 8 shows the inactivation efficiency of ultrasonic enhanced peracetic acid treatment against Escherichia coli in actual sewage; 1. Water inlet pipe; 2. Circular gate I; 3. Flow retarder; 4. Bypass pipe; 5. Circular gate II; 6.

Flashboard; 7. Drainage pipe; 8. Ultrasonic transducer; 9. Power distribution cabinet; 10.

Ultrasonic generator; 11. Water level monitor, 12. Hydraulic controller; 13. Water level controller; 14. Automatic dosing box; 15. Stirrer; 16. Water outlet pipe; 17. Circular gate III; 18.

Butterfly valve.

DESCRIPTION OF THE INVENTION

It should be noted that the embodiments in the present invention and the features in the embodiments can be combined with each other without conflict. The described embodiment is only a part of the embodiment of the present invention, not the whole embodiment. All other embodiments obtained by ordinary people in the field without creative work belong to the scope of protection of the present invention. The present invention will be described in detail with reference to the attached drawings and examples.

The invention provides a method and a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, which comprises the following steps: removing insoluble impurities in sewage by precipitation;

treating the sewage by ultrasonic radiation, so that the agglomerated pathogent&/505018 microorganisms in the sewage are dispersed into a single cell state; wherein ultrasonic waves with at least two frequencies are arranged in the ultrasonic radiation treatment; when sewage is treated by ultrasonic radiation with different frequencies, the agglomerated pathogenic microorganisms in the water are dispersed into single cell state, the cell membrane is destroyed, and the resistance of pathogenic microorganisms to chemical disinfectants is obviously reduced, adding a strong oxidant into the sewage treated by ultrasonic radiation, and stirring with a stirrer 15 to inactivate of pathogenic microorganisms in the sewage, concretely, the peracetic acid enters cells through molecular diffusion or directly penetrating damaged cell membranes to oxidize substances in cells, and further inactivate pathogenic microorganisms in water, wherein the strong oxidant is peracetic acid solution;

Further, the ultrasonic radiation treatment further comprises: low-frequency ultrasonic waves are arranged below the sewage level, and the low-frequency ultrasonic waves are arranged vertically below the sewage level by using a probe-type ultrasonic transducer; high-frequency ultrasonic waves are arranged at the bottom of the sewage, and the high-frequency ultrasonic waves are arranged horizontally at the bottom of the solution by using a planar ultrasonic transducer.

Further, the precipitation time is not less than 10 min.

Further, the time of ultrasonic radiation treatment is not less than 10 min.

Further, the ultrasonic radiation treatment further comprises: an ultrasonic generator outputs sinusoidal signals for conversion into ultrasonic waves, and the power density of the ultrasonic generator is not lower than 0.038W/mL.

Further, the ultrasonic radiation treatment further comprises: the low-frequency ultrasonic wave is arranged 2 cm below the sewage level.

Further, the concentration of peracetic acid in sewage is not less than 26 um.

Further, the mass fraction of peracetic acid in peracetic acid solution is not less than 18.04%.

Further, the peracetic acid solution also contains hydrogen peroxide, and the mass fraction of hydrogen peroxide is not less than 12%.

Further, the rotation speed of the stirrer 15 is not less than 150 revolutions, so as to ensuk&/505018 the full mixing of pathogenic microorganisms and peracetic acid in water.

The invention also provides a device for inactivating pathogenic microorganisms in water by acoustic enhanced peracetic acid, which sequentially comprises a sewage inlet area, an ultrasonic radiation area and a peracetic acid reaction area.

The sewage inlet area is provided with a water inlet pipe 1, a retarder 3 and a bypass pipe 4, wherein a circular gate I 2 is installed on the water inlet pipe 1, and a circular gate II 5 is installed on the bypass pipe 4. When the gate and ram are damaged, resulting in device blockage or equipment damage and maintenance, the water in the sewage inlet area can be discharged through the bypass pipe 4. Meanwhile, when the inlet water quality is good and does not need to be treated, the inlet water can be directly discharged from the bypass pipe, and the flow retarder 3 is used to ensure the stability of the water flow speed.

The ultrasonic radiation area is provided with a drainage pipe 7, an ultrasonic transducer 8, a power distribution cabinet 9, an ultrasonic generator 10, a water level monitor 11, and a butterfly valve 18. The butterfly valve 18 is installed on the drainage pipe 7. The ultrasonic generator 10 can convert the commercial power into alternating current signals to matched with the ultrasonic transducer 8. The ultrasonic transducer 8 can generate at least three different ultrasonic frequencies of 60 kHz, 430 kHz and 1120 kHz. When the ultrasonic equipment fails, the sewage in the ultrasonic radiation area can be discharged through the drain pipe 7 at the bottom for quick maintenance.

A gate 6 is arranged between the sewage inlet area and the ultrasonic radiation area for controlling the water flow.

The peracetic acid reaction zone is provided with a water level controller 13, an automatic dosing box 14, a stirrer 15 and a water outlet pipe 16, and a circular gate III 17. The circular gate

IIT 17 is installed on the water outlet pipe 16. The stirrer 15 is used for fully mixing the peracetic acid solution and sewage in the peracetic acid reaction zone. The automatic dosing box 14 is used for dosing the peracetic acid solution with appropriate concentration into the peracetic acid reaction zone.

A hydraulic controller 12 and a power distribution cabinet 9 connected with the hydraulké/505018 controller 12 are arranged between the ultrasonic radiation zone and the peracetic acid reaction zone, and the water level controller 13 in the peracetic acid reaction zone and the water level monitor 11 in the ultrasonic radiation zone are both electrically connected with the hydraulic controller 12.

The sewage to be disinfected first enters the sewage inlet area, and insoluble solid particles in the sewage are removed by precipitation in the sewage inlet area; the settled sewage enters the ultrasonic radiation area. In the ultrasonic radiation area, the ultrasonic generator 10 controls the ultrasonic transducer 8 to generate ultrasonic waves with different frequencies and powers, and the ultrasonic time in the ultrasonic radiation area is at least 10 min. The sewage after ultrasonic treatment enters the peracetic acid reaction zone. In the peracetic acid reaction zone, the automatic dosing box 14 feeds peracetic acid solution with appropriate concentration according to the set flow rate, and the peracetic acid reaction zone is equipped with a stirrer 15. The pathogenic microorganisms after ultrasonic treatment are further inactivated in the peracetic acid reaction zone for at least 10min under the full mixing of the stirrer 15. After a period of reaction, the sewage is discharged from the peracetic acid reaction zone through the water outlet pipe 16.

The invention provides a device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, and the specific starting steps are as follows:

The sewage to be disinfected enters the sewage inlet area through the water inlet pipe 1, and then enters the ultrasonic radiation area through the retarder 3 and the flashboard 6. The flow retarder 3 can adjust the inlet water flow to guarantee the flow rate stable. A circular gate I 2 installed on the water inlet pipe 1 can control the inflow. A bypass pipe 4 is arranged at the bottom of the sewage inlet area, and a circular gate Il 5 is arranged on the bypass pipe 4. When the device is blocked or the equipment is damaged and needs to be maintained, the water in the device can be discharged through the bypass pipe 4. Meanwhile, when the influent water quality is good, the influent water also can be directly discharged from the bypass pipe 4. The ultrasonic transducer 8 is controlled and adjusted by the ultrasonic generator 10, and the power distribution cabinet 9 supplied them with electric energy. The ultrasonic transducer 8 can be customized according to parameters such as ultrasonic frequency range, hydraulic retention time, treatment flow scale, etc. À drain pipe 7 is arranged at the bottom of the ultrasonic radiation area, andlä}505018 butterfly valve 18 is installed on the drain pipe 7. The water flow after ultrasonic treatment enters the peracetic acid reaction zone through the water level controller 13. The hydraulic controller 12 controls the water level controller 13 according to the water level monitored by the water level monitor 11 to adjust the water level in the peracetic acid reaction zone. In the peracetic acid reaction zone, the peracetic acid solution is added into the peracetic acid reaction zone by the automatic dosing box 14, and then is stirred and mixed by the stirrer 15 to make it fully react.

The size of the reaction zone is determined according to the hydraulic retention time of sewage in the peracetic acid reaction zone, and the treated water flow is finally discharged from the device by the water outlet pipe 16. The outlet pipe 16 is provided with a circular gate III 17, and all the electrical instruments in this device are powered by the power distribution cabinet 9.

Example 1

In order to study the inactivation performance of ultrasound combined with peracetic acid,

Escherichia coli suspension was divided into different groups with a volume of 500 mL. Before sterilization, the volume of Escherichia coli cell suspension added to the reactor was determined by measuring the absorbance at 600nm, so as to achieve a consistent initial cell concentration of (1.3-1.6)x107 CFUml". For ultrasonic treatment alone, the Escherichia coli suspension enters the sewage inflow area, and then enters the ultrasonic radiation area from the sewage inflow area, and the Escherichia coli suspension is ultrasonically treated by different frequencies (60 kHz, 430 kHz and 1120 kHz) for 10 min. For peracetic acid treatment alone, the suspension of

Escherichia coli was added to the peracetic acid reaction zone, and the peracetic acid solution was added to into the peracetic acid reaction zone through an automatic dosing box to treat the bacterial suspension for 10 min. For the ultrasonic enhanced peracetic acid treatment, the

Escherichia coli suspension enters the sewage inflow area, and then enters the ultrasonic radiation area from the sewage inflow area. In the ultrasonic radiation area, the sewage is treated for 10min by ultrasonic waves with different frequencies (60 kHz, 430 kHz and 1120 kHz). Then, the sewage treated by ultrasonic waves enters the peracetic acid reaction area, and peracetic acid continues to treat the Æscherichia coli suspension for 10min. During the treatment, the concentration of peracetic acid (PAA) was 26 uM.

From Table 1, it can be seen that the inactivation effect of Escherichia coli treated wit#505018 different frequencies (60 kHz, 430 kHz and 1120 kHz) for 10 min is poor, with only 0.13-log, 0.09-log and 0.16-log respectively. Different from ultrasonic treatment alone, the inactivation of peracetic acid alone for 10min on Escherichia coli can reach 2.29-log. The peracetic acid alone shows excellent disinfection effect, mainly because peracetic acid can oxidize protein and sulfhydryl group (-SH) and disulfide bond (S-S) in enzymes, and finally leading to apoptosis of pathogenic cells. Compared with ultrasonic treatment alone or peracetic acid treatment alone, the inactivation efficiency of Escherichia coli was significantly improved after the ultrasonic (60 kHz, 430 kHz and 1120 kHz) enhanced peracetic acid treatment for 10 min, reaching 4.69-log, 4.1-log and 4.06-log respectively. It can be found that although the inactivation effect of ultrasonic radiation alone on Escherichia coli is poor in a short time, the cells of Escherichia coli after ultrasonic pretreatment are more dispersed, the cell membrane is perforated and the cell contents are leaked. The ultrasonic treatment makes Escherichia coli more sensitive to peracetic acid and further improves the bactericidal effect of peracetic acid.

Example 2

The volume of Escherichia coli cell suspension added to the reactor was determined by measuring the absorbance at 600nm, so that the initial cell concentration was (1.3-1.6) x 10’

CFU ml. 500 mL Escherichia coli bacterial liquid first enters the sewage inlet area, and then enters the ultrasonic radiation area. Turn on the ultrasonic generator 10 and adjust the ultrasonic frequency of the ultrasonic generator to be 60 kHz. The electric signal generated by the ultrasonic generator 10 is transmitted to the ultrasonic transducer 8, and the ultrasonic transducer 8 converts the electric signal into 60 kHz ultrasonic wave. The Escherichia coli bacterial liquid is subjected to 60 kHz low-frequency ultrasonic treatment for 10min in the ultrasonic radiation area, and the ultrasonic treated Escherichia coli bacterial liquid enters the peracetic acid reaction area.

In the peracetic acid reaction zone, the stirrer 15 and the automatic dosing box 10 are turned on.

Peracetic acid is added into the reaction zone through the automatic dosing box 10, and peracetic acid in sewage is fully mixed with Escherichia coli under the stirring action of the stirrer 15.

Escherichia coli bacterial liquid is treated in the peracetic acid reaction zone for 10 min, the treated water sample is collected. The changes of the micro-morphology of Escherichia coli cells in the water sample are analyzed by transmission electron microscope and scanning electrd1/505018 microscope. In the peracetic acid reaction zone, the concentration of peracetic acid was 26 um.

Scanning electron microscope (SEM) was used to observe the micromorphological changes of Escherichia coli before and after different treatments. As shown in Fig. 4, untreated

Escherichia coli has uniform, smooth and intact rod-shaped cells with clear and full microstructure. After ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment, some depressions appeared on the surface of Escherichia coli cells, including cell collapse, cell surface perforation and outer wall rupture of Escherichia coli. The results showed that ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment could effectively destroy the cell structure of

Escherichia coli.

Similarly, the influence of ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment on the morphology of Escherichia coli cells was further analyzed by transmission electron microscope. As shown in Fig. 4, the untreated Escherichia coli cell structure is normal and the cell membrane structure is clear. After ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment, obvious changes occurred in Escherichia coli cells, including blurred cell membrane and leakage of cell contents. The results further confirmed that ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment can effectively kill Escherichia coli by destroying the cell structure.

Example 3

The volume of Escherichia coli cell suspension added to the reactor was determined by measuring the absorbance at 600 nm, so that the initial cell concentration was (1.3-1.6) x 10’

CFU ml. 500 mL of Escherichia coli bacterial liquid first enters the sewage inlet area, then enters the ultrasonic radiation area from the sewage inlet area. Turn on the ultrasonic generator 10, and the ultrasonic frequency of the ultrasonic generator is adjusted to be 60 kHz. The electric signal generated by the ultrasonic generator 10 is transmitted to the ultrasonic transducer 8, and the ultrasonic transducer 8 converts the electric signal into 60 kHz ultrasonic wave. The

Escherichia coli liquid is treated in the ultrasonic radiation area for 10 min, and the Escherichia coli sample after ultrasonic treatment is taken and stored at 4°C for analysis. After ultrasonic treatment, the Escherichia coli bacteria solution enters the peracetic acid reaction zone. In the peracetic acid reaction zone, the stirrer 15 and the automatic dosing box 14 are turned ohU505018

Peracetic acid is added into the reaction zone through the automatic dosing box 14, and peracetic acid is fully mixed with Escherichia coli under the stirring action of the stirrer 15. Escherichia coli bacterial liquid is treated in the peracetic acid reaction zone for 10 min. In addition,

Escherichia coli with the cell concentration of (1.3-1.6)x10” CFU ml! is treated by peracetic acid alone for 10 min, and samples are taken and stored at 4°C for analysis. The concentration of peracetic acid is 26 pM. Protein concentration of Escherichia coli in the sample is determined by protein concentration determination kit.

The changes of protein level of Escherichia coli before and after sterilization are determined by protein concentration determination kit. As shown in Fig. 5, compared with the untreated group, the protein concentration of Escherichia coli treated by ultrasound alone decreases from 0.27 mg mL“ to 0.25 mg mL“. Peroxyacetic acid alone also reduces the intracellular protein content of Escherichia coli. Notably, the concentration of Escherichia coli protein is significantly decreased after ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment.

Example 4

To study the effects of pH on the inactivation of Escherichia coli by ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment, the volume of the cell suspension spiked into the reactor was determined by measuring absorbance at 600 nm to achieve a consistent initial cell concentration of (1.3-1.6) x10” CFU mL”, and the volume was 500 mL. The pH values of bacterial suspension are adjusted to 3, 5, 7 and 10 respectively. 500 mL of Escherichia coli bacteria solution with different pH first enters the sewage inlet area, and then enters the ultrasonic radiation area from the sewage inlet area. Turn on the ultrasonic generator 10, and adjust the ultrasonic frequency of the ultrasonic generator to be 60 kHz. The electric signal generated by the ultrasonic generator 10 is transmitted to the ultrasonic transducer 8, the ultrasonic transducer 8 converts the electric signal into 60 kHz ultrasonic wave. The Escherichia coli bacterial liquid is ultrasonically treated at 60 kHz for 10min in the ultrasonic radiation area.

After ultrasonic treatment, the Escherichia coli bacteria solution enters the peracetic acid reaction zone. In the peracetic acid reaction zone, the stirrer 15 and the automatic dosing box 10 are turned on, peracetic acid is added into the reaction zone under the stirring action of the stirret/505018 15. Escherichia coli bacterial liquid is treated in the peracetic acid reaction zone for 10 min, and the treated water samples are collected. The plate counting method is used to evaluate the inactivation effect of ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment on

Escherichia coli under different pH conditions. In the peracetic acid reaction zone, the concentration of peracetic acid is 26 pM.

In this example, the inactivation experiment of Escherichia coli by ultrasonic enhanced peracetic acid (US—PAA) is carried out at different pH values. As can be seen from Fig. 6, the inactivation efficiency of Escherichia coli by ultrasonic enhanced peracetic acid (US—PAA) is higher than 4-log in acidic state (pH<7). When pH>7, the inactivation of Escherichia coli by ultrasound-enhanced peracetic acid (US—PAA) is obviously reduced. The results show that ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment had a good inactivation effect on

Escherichia coli under acidic conditions.

Example 5

To study the effects of temperature on the inactivation of Escherichia coli by ultrasonic enhanced peracetic acid (60 kHz—PAA) treatment, the volume of the cell suspension spiked into the reactor was determined by measuring absorbance at 600 nm to achieve a consistent initial cell concentration of (1.3-1.6) x10” CFU mL. The temperature of bacterial suspension is adjusted to 5°C, 10°C, 25°C and 38°C respectively. 500 mL of Escherichia coli bacteria liquid with different pH first enters the sewage inflow area, and then enters the ultrasonic radiation area from the sewage inflow area. The ultrasonic generator 10 is turned on, and the ultrasonic frequency of the ultrasonic generator 10 is adjusted to be 60 kHz. The electric signal generated by the ultrasonic generator 10 is transmitted to the ultrasonic transducer 8, and the ultrasonic transducer 8 converts the electric signal into 60 kHz ultrasonic wave. The Escherichia coli bacteria liquid is treated in the ultrasonic radiation area for 10 min. After ultrasonic treatment, the Escherichia coli bacteria solution enters the peracetic acid reaction zone. In the peracetic acid reaction zone, the stirrer 15 and the automatic dosing box 14 in the reaction zone are turned on.

Peracetic acid is added into the reaction zone, and peracetic acid in the sewage is fully mixed with Escherichia coli under the stirring action of the stirrer 15. The Escherichia coli bacterial solution is treated in the peracetic acid reaction zone for 10 min, and the treated water sample$/505018 are collected. The inactivation effect of ultrasonic enhanced peracetic acid treatment (US—PAA) on Escherichia coli under different pH conditions was calculated by plate counting method. In the peracetic acid reaction zone, the concentration of peracetic acid is 26 uM.

The inactivation effect of peracetic acid on bacteria increases with the increase of temperature. As shown in Fig. 7, with the temperature increasing from 5°C to 38°C, the inactivation performance of ultrasonic enhanced peracetic acid (60 kHz—PAA) on Escherichia coli increased from 1.84-log to 4.99-log. Peroxyacetic acid can produce ‘Oz at high temperature, which promotes the inactivation of Escherichia coli. In addition, the ultrasonic pretreatment can reduce the resistance of cells to peracetic acid by destroying cell membranes, thus enhancing the inactivation of peracetic acid.

Example 6

The inactivation effect of ultrasonic enhanced peracetic acid (60 kHz—PAA) on

Escherichia coli in different water qualities (ultra-pure water, untreated influent, secondary effluent and tertiary effluent) is discussed. Considering the complexity of microbial composition in real sewage, the real sewage is autoclaved for 20 min in an autoclave to eliminate the influence of original microorganisms in sewage. The volume of the cell suspension spiked into the reactor was determined by measuring absorbance at 600 nm to achieve a consistent initial cell concentration of (1.3-1.6) x10” CFU mL”. 500 mL of different water quality containing

Escherichia coli first enters the ultrasonic radiation zone, and the ultrasonic generator 10 is turned on, and the ultrasonic frequency of the ultrasonic generator is adjusted to be 60 kHz. The electric signal generated by the ultrasonic generator 10 is transmitted to the ultrasonic transducer 8, and the ultrasonic transducer 8 converts the electric signal into 60 kHz ultrasonic waves. The sewage first enters the sewage inlet area, and then enters the ultrasonic radiation area from the sewage inlet area and is subjected to 60 kHz ultrasonic treatment for 10 min. The sewage after ultrasonic treatment enters the peracetic acid reaction zone. In the peracetic acid reaction zone, the stirrer 15 and the automatic dosing box 14 are turned on. Peracetic acid is added into the reaction zone, and peracetic acid in the sewage is fully mixed with Escherichia coli under the stirring action of the stirrer 15. Sewage is treated in the peracetic acid reaction zone for 10min,

and the treated water samples are collected. The inactivation effect of Escherichia coli B3J505018 ultrasonic enhanced peracetic acid (US—PAA) treatment in different water qualities is evaluated by plate counting method. In the peracetic acid reaction zone, the concentration of peracetic acid was 26 uM.

As shown in Fig. 8, the inactivation performance of ultrasound-enhanced peracetic acid (US—PAA) treatment in ultra-pure water is the highest among all samples, which is 4.67-log.

The inactivation performance was reduced by 25.05% in the tertiary effluent from sewage treatment plant compared with that in the ultrapure water. Compared with ultra-pure water, the disinfection performance decreased by 51.39% in the secondary effluent. The disinfection performance of untreated effluent was the lowest, with 0.49-log. Previous studies have also shown that the disinfection performance of peracetic acid is easily affected by organic matter, inorganic particles, suspended solids and other substrates in water. The higher the COD content in the actual wastewater, the more serious the organic pollution is, which seriously affects the inactivation efficiency of Escherichia coli in the actual wastewater by ultrasonic enhanced peracetic acid treatment (60kHz—PAA). It can be seen from the above results that the typical deactivation order is: ultra-pure water > tertiary effluent > secondary effluent > untreated influent.

Table 1 shows the inactivation efficiency of Escherichia coli in water by ultrasonic alone, peracetic acid alone and ultrasonic enhanced peracetic acid treatment.

A

The above is only the preferred embodiment of this application, but the protection scope of this application is not limited to this. Any change or replacement that can be easily thought of by a person familiar with this technical field within the technical scope disclosed in this application should be included in the protection scope of this application. Therefore, the protection scope of this application should be based on the protection scope of the claims.

Claims

CLAIMS LU505018

I. A method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, comprising: removing insoluble impurities in sewage by precipitation; carrying out ultrasonic radiation treatment on sewage, wherein the ultrasonic radiation treatment at least comprises two different ultrasonic frequencies; adding strong oxidant into the sewage treated by ultrasonic radiation to further inactivate pathogenic microorganisms in the sewage, wherein the strong oxidant is peracetic acid solution.
2. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the ultrasonic radiation treatment further comprises: arranging low-frequency ultrasonic probe below the sewage level, arranging high-frequency ultrasonic transducer at the bottom of the sewage.
3. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the precipitation time is not less than 10 min.
4. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the ultrasonic radiation treatment time is not less than 10min.
5. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the ultrasonic radiation treatment further comprises: outputting a sinusoidal signal for conversion into ultrasonic waves by an ultrasonic generator (10), wherein the power density of the ultrasonic generator (10) 1s not lower than

0.038W/mL.
6. The method for inactivating pathogenic microorganisms in water by acoustic wav&/505018 enhanced peracetic acid according to claim 2, wherein the ultrasonic radiation treatment further comprises: arranging the low-frequency ultrasonic probe 2 cm below the sewage level.
7. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the concentration of peracetic acid in sewage 1s not less than 26 uM.
8. The method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to claim 1, wherein the mass fraction of peracetic acid in the peracetic acid solution is not less than 18.04%.
9. A device for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid, applied to the method for inactivating pathogenic microorganisms in water by acoustic wave enhanced peracetic acid according to any one of claims 1 to 8, comprising a sewage inlet area, an ultrasonic radiation area and a peracetic acid reaction area which are sequentially communicated; the sewage inlet area is provided with a water inlet pipe (1), a flow retarder (3) and a bypass pipe (4) arranged at the bottom of the sewage inlet area; a circular gate I (2) is installed on the water inlet pipe (1), and a circular gate II (5) is installed on the bypass pipe (4); an ultrasonic radiation area is provided with a drainage pipe (7), an ultrasonic transducer (8), a power distribution cabinet (9), an ultrasonic generator (10) and a water level monitor (11), and a butterfly valve (18) is installed on the drainage pipe (7); a flashboard (6) is arranged between the sewage inlet area and the ultrasonic radiation area; the peracetic acid reaction zone is provided with a water level controller (13), an automatic dosing box (14), a stirrer (15) and a water outlet pipe (16), and a circular gate III (17) is installed on the water outlet pipe (16); a hydraulic controller (12) and a power distribution cabinet (9) connected with the hydraulic controller (12) are arranged between the ultrasonic radiation zone and the peracetic acid reaction zone, and the water level controller (13) in the peracetic acid reaction zone and the water level505018 monitor (11) in the ultrasonic radiation zone are both electrically connected with the hydraulic controller (12).

PATENTANSPRÜCHE LU505018

1. Ein Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure, umfassend: Entfernen von unlôslichen Verunreinigungen im Abwasser durch Ausfällung; Durchführen einer Ultraschall-Strahlenbehandlung des Abwassers, wobei die Ultraschall-Strahlenbehandlung mindestens zwei verschiedene Ultraschallfrequenzen umfasst; Zugabe eines starken Oxidationsmittels in das Abwasser, behandelt mit Ultraschallstrahlung, um pathogene Mikroorganismen im Abwasser weiter zu inaktivieren, wobei das starke Oxidationsmittel eine Peressigsäurelôsung ist.

2. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei die Ultraschall-Strahlenbehandlung weiterhin umfasst: Anordnen einer Niederfrequenz-Ultraschallsonde unterhalb des Abwasserspiegels; Anordnen eines Hochfrequenz-Ultraschallwandlers am Boden des Abwassers.

3. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei die Fällungszeit nicht weniger als 10 Minuten beträgt.

4. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei die Behandlungszeit mit Ultraschallstrahlung nicht weniger als 10 Minuten beträgt.

5. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei die Ultraschall-Strahlenbehandlung ferner umfasst: Ausgeben eines sinusfôrmigen Signals zur Umwandlung in Ultraschallwellen durch einen Ultraschallgenerator (10), wobei die Leistungsdichte des Ultraschallgenerators (10) nicht geringer als 0,038 W/mL ist.

6. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch dié/505018 mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 2, wobei die Ultraschall-Strahlenbehandlung weiterhin umfasst: Anordnen der Niederfrequenz-Ultraschallsonde 2 cm unterhalb des Abwasserspiegels.

7. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei die Konzentration der Peressigsäure im Abwasser nicht weniger als 26 uM beträgt.

8. Das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach Anspruch 1, wobei der Massenanteil der Peressigsäure in der Peressigsäurelôsung nicht weniger als 18,04 % beträgt.

9. Fine Vorrichtung zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure, angewandt auf das Verfahren zur Inaktivierung von pathogenen Mikroorganismen in Wasser durch die mit akustischen Wellen verstärkte Peressigsäure nach einem der Ansprüche 1 bis 8, umfassend einen Abwassereinlassbereich, einen Ultraschallstrahlungsbereich und einen Peressigsäure-Reaktionsbereich, die nacheinander miteinander verbunden sind; der Abwassereinlassbereich ist mit einem Wassereinlassrohr (1), einem Stromungsverzogerer (3) und einem Bypassrohr (4), angeordnet am Boden des Abwassereinlassbereichs, versehen; ein kreisfôrmiges Tor I (2) ist an dem Wassereinlassrohr (1) installiert und ein kreisfôrmiges Tor II (5) ist an dem Bypassrohr (4) installiert; ein Ultraschallstrahlungsbereich ist mit einem Abflussrohr (7), einem Ultraschallwandler (8), einem Stromverteilerschrank (9), einem Ultraschallgenerator (10) und einem Wasserstand-Monitor (11) versehen, und auf dem Abflussrohr (7) ist eine Absperrklappe (18) installiert; zwischen dem Abwassereinlassbereich und dem Ultraschallstrahlungsbereich ist ein Flashboard (6) angeordnet;

der Peressigsäure-Reaktionsbereich ist mit einem Wasserstandsregler (13), einekt/505018 automatischen Dosierkasten (14), einem Rührer (15) und einem Wasserauslassrohr (16) ausgestattet, und an dem Wasserauslassrohr (16) ist ein kreisfôrmiger Tor III (17) angebracht;

ein Hydraulikregler (12) und ein mit dem Hydraulikregler (12) verbundener Stromverteilerschrank (9) sind zwischen dem Ultraschallstrahlungsbereich und dem Peressigsäure-Reaktionsbereich angeordnet, und der Wasserstandsregler (13) im Peressigsäure-Reaktionsbereich und der Wasserstand-Monitor (11) im Ultraschallstrahlungsbereich sind beide elektrisch mit dem Hydraulikregler (12) verbunden.