CN111825252A

CN111825252A - Wastewater oxidation device and system and wastewater advanced treatment oxidation method

Info

Publication number: CN111825252A
Application number: CN201910319187.4A
Authority: CN
Inventors: 王辉; 高嵩; 孙钰林; 余正齐; 孙飞
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-04-19
Filing date: 2019-04-19
Publication date: 2020-10-27

Abstract

The invention relates to the field of sewage treatment, and discloses a wastewater oxidation device and system and an oxidation method for advanced wastewater treatment, wherein the device comprises a hollow cylinder body with an upper end cover and a lower end cover, and the upper end cover and the lower end cover respectively seal the top end and the bottom end of the hollow cylinder body; the bottom of the oxidation section is adjacent to the top of the filtration separation section through a porous membrane, and the porous membrane divides the oxidation section and the filtration separation section into two independent spaces. The oxidation device and the oxidation system for advanced treatment of industrial wastewater and the oxidation method for advanced treatment of wastewater provided by the invention can realize advanced treatment of refractory organic pollutants in industrial wastewater and improve advanced oxidation treatment efficiency.

Description

Wastewater oxidation device and system and wastewater advanced treatment oxidation method

Technical Field

The invention relates to the field of sewage treatment, in particular to a wastewater oxidation device and system for advanced treatment of industrial wastewater and an oxidation method for advanced treatment of wastewater.

Background

With the rapid development of industry, the contradiction between production and environment is increasingly prominent, and environmental protection has become a measure index of economic construction.

Along with the increasing tightening of water environment protection indexes and the complication of processing technology, various industries (such as petrochemical, pharmaceutical, steel, printing and dyeing and the like) face increasingly severe environmental protection pressure, and the traditional industrial wastewater treatment process (primary treatment and secondary biochemical) cannot meet new standards and future environmental protection requirements, so that the development of a novel efficient industrial wastewater advanced treatment process has important significance for sewage upgrading and deep reaching standards.

In the existing industrial wastewater treatment process, a biochemical process is an important stage for removing organic pollutants in wastewater, but the removal effect of the stage on the organic pollutants difficult to biodegrade is very little, so that the key point for improving the effluent quality of the industrial wastewater lies in the removal of the organic pollutants difficult to degrade. The existing advanced treatment process has various types, such as coagulating sedimentation, activated carbon adsorption, membrane separation and the like, although the process can remove organic pollutants which are difficult to degrade in industrial wastewater to a certain degree, secondary pollution can be generated, such as sludge and inactivated activated carbon formed by using a large amount of medicaments; or high construction and operation costs, such as membrane module replacement and maintenance, etc.

The advanced oxidation technology is a novel advanced wastewater treatment technology, and utilizes free radicals (such as hydroxyl free radical. OH) which have strong oxidizing property and no selectivity and are generated under different conditions to oxidize and degrade refractory organic matters in wastewater to easily biodegradable micromolecule organic matters or CO₂And water. Common advanced oxidation treatment technologies include fenton oxidation, ozone catalytic oxidation, ultraviolet light catalytic process and the like, but the existing processes have limited treatment efficiency and high cost, such as large consumption of fenton oxidationThe preparation is measured, the iron-containing sludge is generated, the problems of tail gas treatment, safety, catalyst inactivation and the like exist in ozone catalytic oxidation, and the light energy utilization rate of the conventional ultraviolet light catalysis process is low. Therefore, how to make best use of the advantages and avoid the disadvantages and how to construct an efficient advanced oxidation system is the key point of research on the advanced treatment of industrial wastewater.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a wastewater oxidation device and system and a wastewater oxidation method for advanced treatment, wherein the wastewater oxidation device and system can realize advanced treatment of refractory organic pollutants in industrial wastewater and improve advanced oxidation treatment efficiency.

In order to accomplish the above objects, according to one aspect of the present invention, there is provided an apparatus for oxidizing waste water, wherein the apparatus includes a hollow cylinder having an upper end cap and a lower end cap, the upper end cap and the lower end cap sealing a top end and a bottom end of the hollow cylinder, respectively;

the inner space of the hollow cylinder comprises an oxidation section and a filtering separation section, wherein the oxidation section comprises an exhaust valve arranged on an upper end cover, a porous membrane arranged at the bottom of the oxidation section, a water inlet and a sewage outlet; the filtration separation section comprises a port for introducing gas or discharging treated wastewater;

the bottom of the oxidation section is adjacent to the top of the filtration and separation section through the porous membrane, and the porous membrane divides the oxidation section and the filtration and separation section into two independent spaces.

The invention provides an oxidation method for advanced wastewater treatment, wherein the method is carried out in the oxidation device for wastewater, and comprises the steps of feeding wastewater and an optional catalyst into an oxidation section through a water inlet under the irradiation of a vacuum ultraviolet light source, feeding gas into a filtering separation section through a port for introducing gas or discharging treated wastewater, and feeding the gas into the oxidation section after the gas is subjected to gas distribution through a porous membrane to be in contact with the wastewater for oxidation treatment; and after the treatment is finished, stopping introducing the gas, filtering the treated wastewater by the porous membrane, then entering a filtering separation section, and discharging the gas or the treated wastewater by using an outlet discharge device.

In a third aspect, the present invention provides a wastewater oxidation system, wherein the wastewater oxidation system comprises a water inlet unit, a gas delivery unit, the wastewater oxidation device of the present invention, and a water outlet unit,

the water inlet unit is used for sending the wastewater and an optional catalyst into an oxidation section of a wastewater oxidation device;

the gas conveying unit is used for introducing gas into the filtering separation section, and the gas enters the oxidation section after being subjected to gas distribution through the porous membrane;

the wastewater oxidation device is used for contacting wastewater and an optional catalyst with gas in an oxidation section for oxidation treatment under the irradiation of a vacuum ultraviolet light source; after the treatment is finished, the treated wastewater enters a filtering separation section after being filtered by a porous membrane;

and the water outlet unit is an oxidation device for discharging the oxidized and filtered wastewater out of the wastewater.

The fourth aspect of the invention provides an oxidation method for advanced wastewater treatment, wherein the method is carried out in the wastewater oxidation system of the invention, and comprises the steps of starting a water inlet pump, sending wastewater and an optional catalyst added through a catalyst adding unit into an oxidation section of a wastewater oxidation device through a water inlet, starting a vacuum ultraviolet light source, an air pump and an air inlet valve on an air inlet pipeline, closing an water outlet pump and an water outlet valve on a water outlet pipeline, introducing gas into a filtering separation section through a port for introducing gas or discharging treated wastewater, and allowing the gas to enter the oxidation section after gas distribution through a porous membrane to contact with the wastewater for oxidation treatment; after the treatment is finished, the air pump and the air inlet valve on the air inlet pipeline are closed, the water outlet pump and the water outlet valve on the water outlet pipeline are opened, and the treated wastewater enters the filtering and separating section after being filtered by the porous membrane and is discharged out of the system.

The oxidation device and the system for advanced treatment of industrial wastewater and the oxidation method for advanced treatment of wastewater provided by the invention can realize advanced treatment of refractory organic pollutants in industrial wastewater, improve advanced oxidation treatment efficiency, have the characteristics of easily controlled reaction conditions, high treatment efficiency, strong membrane pollution resistance and the like, and have the characteristics of short process flow, small occupied area and easy operation.

Drawings

FIG. 1 is a view for explaining an embodiment of an apparatus for oxidizing waste water according to the present invention;

fig. 2 is a view for explaining another embodiment of the wastewater oxidation apparatus according to the present invention.

Description of reference numerals:

1: and (3) gas source 2: gas rotor flowmeter

3: the intake valve 4: three-way valve

5: ports for introducing gases or discharging treated waste water

6: the lower end cover 7: porous membrane

8: the hollow cylinder 9: vacuum ultraviolet lamp with integrated structure

10: and (3) a water inlet pump 11: catalyst feeding unit

12: water inlet 13: water outlet valve

14: a vacuum pressure gauge 15: water outlet pump

16: exhaust valve 17: drain outlet

18: the blow-off valve 19: and (4) an upper end cover.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, the terms "upper", "lower", "bottom" and "top" are used to indicate the orientation of the wastewater oxidation apparatus in the use state, which is determined based on the horizontal plane; the terms "inner" and "outer" are used in the sense of the internal space of the hollow cylinder of the wastewater oxidation plant, for example: "inwardly" refers to a direction toward the interior space of the hollow cylinder and "outwardly" refers to a direction away from the interior space of the hollow cylinder.

According to a first aspect of the present invention, there is provided an apparatus for oxidizing waste water, comprising a hollow cylinder having an upper end cap and a lower end cap, the upper end cap and the lower end cap sealing a top end and a bottom end of the hollow cylinder, respectively; the inner space of the hollow cylinder comprises an oxidation section and a filtering separation section.

According to the wastewater oxidation device of the present invention, in order to ensure the wastewater treatment capacity and the wastewater treatment effect, the ratio of the height of the oxidation section to the height of the hollow cylinder is preferably 0.85-0.95:1 based on the bottom end of the hollow cylinder.

According to the wastewater oxidation device, the oxidation section comprises the exhaust valve arranged on the upper end cover, the porous membrane arranged at the bottom of the oxidation section, the water inlet and the sewage outlet. The internal space of the oxidation section is a space defined by the upper end cap, the corresponding inner wall of the hollow cylinder, and the porous membrane.

When the wastewater oxidation device operates, the oxidation section is used for contacting the fed wastewater to be treated and the optional catalyst with the introduced gas to perform catalytic oxidation of the wastewater under the irradiation of the vacuum ultraviolet light source.

According to the wastewater oxidation device, the water inlet is used for introducing wastewater to be treated into the oxidation section of the wastewater oxidation device and is usually arranged at the upper part of the oxidation section, and preferably, the ratio of the height of the water inlet to the height of the hollow cylinder is 0.8-0.9:1 by taking the bottom end of the hollow cylinder as a reference. The number of the water inlets can be 1, or more than 2, such as 2-4. When the number of the water inlets is more than two, the heights of the water inlets can be the same or different, preferably the same; in addition, when the number of the water inlets is more than two, the water inlets may be uniformly distributed along the circumferential side wall of the hollow cylinder, or may be non-uniformly distributed along the circumferential side wall of the hollow cylinder, preferably uniformly distributed along the circumferential side wall of the hollow cylinder.

According to the wastewater oxidation device, the sewage draining outlet is used for draining sewage when the wastewater oxidation device is cleaned and subjected to sewage draining treatment, and is usually arranged at the lower part of the oxidation section, and preferably, the ratio of the height of the sewage draining outlet to the height of the hollow cylinder is 0.1-0.2: 1; more preferably, the lower section of the pipe of the sewage draining outlet is in the same plane with the upper surface of the porous membrane, so as to ensure that sewage is fully drained as much as possible. Further preferably, the wastewater oxidation device is further provided with a drain valve for controlling the start and stop of the drain, and the drain valve is arranged on a pipeline connected with the drain. The number of the sewage discharge outlets can be 1, or more than 2, such as 2-4. When the number of the sewage draining outlets is more than two, the heights of the sewage draining outlets can be the same or different, and are preferably the same; in addition, when the number of the drain outlets is more than two, the drain outlets can be uniformly distributed along the circumferential side wall of the hollow cylinder body, also can be non-uniformly distributed along the circumferential side wall of the hollow cylinder body, and preferably are uniformly distributed along the circumferential side wall of the hollow cylinder body.

According to the wastewater oxidation device of the present invention, the exhaust valve is generally disposed on the upper end cap, and is opened to exhaust the exhaust gas generated in the wastewater oxidation device and closed to make the wastewater oxidation device in a closed environment. The number of the exhaust valves is generally 1.

According to the wastewater oxidation apparatus of the present invention, the filtering separation section includes a port for introducing gas or discharging treated wastewater. The internal space of the filtration and separation section is a space defined by the lower end cap, the corresponding inner wall of the hollow cylinder and the porous membrane.

According to the wastewater oxidation apparatus of the present invention, the bottom of the oxidation stage and the top of the filtration and separation stage are adjoined by the porous membrane, and the porous membrane divides the oxidation stage and the filtration and separation stage into two separate spaces.

According to the wastewater oxidation device, the porous membrane integrates the functions of a gas distributor and filtering separation, and the functions of gas distribution and filtering separation are switched by alternately starting and stopping the ventilation pipeline valve and the drainage pipeline valve. When the device is used as a gas distributor, pressurized gas enters wastewater to be treated in an oxidation section above the porous membrane from a filtering separation section below the porous membrane through porous membrane pore passages to form a large amount of micro-fine bubbles and increase the gas-liquid contact area; when the device is used as a filtering and separating device, the filtering and separating section below the porous membrane forms a negative pressure state, oxidized wastewater enters the filtering and separating section below the porous membrane after being filtered by the porous membrane pore passage through the oxidizing section, the porous membrane can be backwashed at the same time, and then the treated wastewater is discharged out of the device.

According to the apparatus for oxidizing waste water of the present invention, the kind of the porous membrane is well known to those skilled in the art. For better achieving the effects of advanced oxidation and advanced filtration treatment of wastewater, preferably, the average pore diameter of the porous membrane is 0.1 to 50 μm, preferably 0.5 to 10 μm; the porosity is 40-50%, most preferably 50%. The porosity is the percentage of the pore volume in the total volume of the porous membrane and is measured by a nitrogen adsorption method. The average pore diameter is determined by a scanning electron microscope method. The porous membrane is made of a material capable of resisting sewage corrosion. In general, the porous membrane may be one or a combination of two or more of a ceramic membrane, a metal membrane, and a polymer membrane, and one preferred embodiment of the present invention is a ceramic membrane.

According to the wastewater oxidation device of the present invention, the porous membrane 7 separates the oxidation section and the filtration separation section into two independent spaces, and thus the porous membrane is hermetically connected to the inner wall of the hollow cylinder. The porous membrane may be fixed to the inner circumferential side wall of the hollow cylinder by a conventional method depending on the material of the porous membrane, and for example, the sealing connection of the porous membrane and the inner circumferential side wall of the hollow cylinder may be achieved by one or more of a rubber ring, a flange connection, and an adhesive bonding.

According to the wastewater oxidation apparatus of the present invention, the port for introducing gas or discharging treated wastewater is provided on the lower end cap, preferably, at the bottom end of the hollow cylinder to facilitate drainage.

According to the wastewater oxidation device provided by the invention, in order to realize vacuum ultraviolet catalytic oxidation of wastewater, the device further comprises one or more than two openings arranged on the upper end cover, and one or more than two vacuum ultraviolet light sources arranged in the oxidation section. In order to protect the vacuum ultraviolet light source from directly contacting with wastewater and enable the vacuum ultraviolet light source to perform normal irradiation, the vacuum ultraviolet light source is generally required to be arranged in the sleeve, the bottom end of the sleeve is closed, the upper end of the sleeve is open, the peripheral side wall of the upper end of the sleeve is fixedly connected with the open hole formed in the upper end cover, so that the upper end of the sleeve is fixed with the upper end cover, and the vacuum ultraviolet light source can be conveniently placed, fixed and taken out. Furthermore, the bottom end of the sleeve may be free, i.e. not fixed.

The sleeve can be made of various materials which can resist water corrosion and do not influence the normal irradiation of the vacuum ultraviolet light source, and is preferably made of quartz material.

The outer peripheral side wall of the upper end of the sleeve may be fixed to the upper end cap by a conventional method, for example, one or more of screwing, bolting, and bonding with an adhesive, depending on the material of the sleeve and the upper end cap.

The number of vacuum ultraviolet light sources is such that the treatment capacity of the wastewater treatment plant can be satisfied, and for example, may be 1 to 10, preferably 1 to 5. As shown in fig. 2, according to an embodiment of the present invention, when more than two vacuum ultraviolet light sources are required to be disposed in the oxidation section, correspondingly, more than two sleeves are correspondingly provided, and correspondingly, more than two openings are provided on the upper end cap, and the peripheral side walls of the upper ends of the sleeves are fixedly connected with the openings provided on the upper end cap, respectively. Preferably, the vacuum ultraviolet light source is a straight tube vacuum ultraviolet lamp. More preferably, the sleeve and the vacuum ultraviolet light source are of an integral structure, namely, the position of the vacuum ultraviolet light source is fixed when the sleeve is fixed in the opening on the end cover. According to a preferred embodiment of the present invention, the vacuum ultraviolet light source is a vacuum ultraviolet lamp 9 of an integrated structure.

According to the wastewater oxidation device provided by the invention, in order to ensure that the vacuum ultraviolet light is radiated to the maximum extent, the vacuum ultraviolet light source (and the sleeve) is arranged along the radial direction of the hollow cylinder and extends to the lower part of the oxidation section. More preferably, the vacuum ultraviolet light source (and sleeve) has a bottom perpendicular to the porous membrane at a distance of 5-20mm, preferably 8-15 mm.

According to the wastewater oxidation device of the present invention, the outer peripheries of the upper end cap and the lower end cap are respectively connected to the top end and the bottom end of the hollow cylinder in a sealing manner, so that the top end and the bottom end of the hollow cylinder are sealed. The sealing connection mode can be selected according to the materials of the hollow cylinder body and the upper end cover and the lower end cover, such as one or more of welding, threaded connection, bonding, buckling connection and clamping groove connection. Preferably, in order to further improve the sealing performance of the wastewater oxidation device, the upper end cover, the hollow cylinder and the lower end cover are of an integrated structure.

According to the wastewater oxidation device of the present invention, the hollow cylinder, the upper end cap and the lower end cap may be made of various materials capable of resisting wastewater corrosion, for example, one or more of a metal material and a non-metal material, the metal material may be stainless steel, the non-metal material may be one or more of an inorganic material and an organic material, for example, one or more of a ceramic material, a glass material and a polymer material (such as organic glass) may be adopted.

In addition, the end surfaces of the upper end cover and the lower end cover can be flat surfaces, and can also be surfaces protruding outwards (such as arc surfaces protruding outwards).

According to an embodiment of the present invention, as shown in fig. 1, the oxidation apparatus for wastewater comprises a hollow cylinder 8 having an upper end cap 19 and a lower end cap 6, the upper end cap 19 and the lower end cap 6 sealing the top end and the bottom end of the hollow cylinder 8, respectively; the inner space of the hollow cylinder 8 comprises an oxidation section and a filtration separation section. The oxidation section comprises an exhaust valve 16 arranged on an upper end cover 19, one or more than two openings, a porous membrane 7 arranged at the bottom of the oxidation section, a water inlet 12, a sewage draining outlet 17 and a sewage draining valve 18, wherein the sewage draining valve 18 is arranged on a pipeline connected with the sewage draining outlet 17. The filtration separation section comprises a port 5 for introducing gas or discharging treated wastewater. The bottom of the oxidation section is adjacent to the top of the filtration separation section through the porous membrane 7, and the porous membrane 7 separates the oxidation section and the filtration separation section into two independent spaces. The device also comprises one or more than two vacuum ultraviolet light sources arranged in the oxidation section. The vacuum ultraviolet light source is arranged in the sleeve, the bottom end of the sleeve is closed, the upper end of the sleeve is open, the peripheral side wall of the upper end of the sleeve is fixedly connected with the open hole formed in the upper end cover 19, the upper end of the sleeve is fixed with the upper end cover 19, and the bottom end of the sleeve is a free end and is not fixed.

According to a third aspect of the present invention, there is provided a wastewater oxidation system, comprising a water inlet unit, a gas delivery unit, a wastewater oxidation device according to the first aspect of the present invention, and a water outlet unit; the water inlet unit is used for sending the wastewater and an optional catalyst into an oxidation section of a wastewater oxidation device; the gas conveying unit is used for introducing gas into the filtering separation section, and the gas enters the oxidation section after being subjected to gas distribution through the porous membrane; the wastewater oxidation device is used for contacting wastewater and an optional catalyst with gas in an oxidation section for oxidation treatment under the irradiation of a vacuum ultraviolet light source; after the treatment is finished, the treated wastewater enters a filtering separation section after being filtered by a porous membrane; and the water outlet unit is an oxidation device for discharging the treated wastewater out of the wastewater. The wastewater oxidation device has been described in detail above, and will not be described in detail here.

According to the wastewater oxidation system of the present invention, as shown in fig. 1, the water inlet unit includes a water inlet pump 10, a water inlet pipeline, and optionally a catalyst adding unit 11 disposed on the water inlet pipeline. The water inlet pipeline is connected with a water inlet of the wastewater oxidation device and is used for conveying the wastewater to be treated into the wastewater oxidation device. The catalyst adding unit 11 can selectively add a catalyst agent into the water inlet pipeline so as to send the wastewater to be treated mixed with the catalyst agent into the wastewater oxidation device.

According to the oxidation system of wastewater of the present invention, as shown in fig. 1, the gas delivery unit includes a gas pump (not shown in the figure), an air inlet pipe, and a gas rotameter 2 and an air inlet valve 3 provided on the air inlet pipe. The gas inlet line is connected to the opening 5 of the wastewater oxidation device for introducing gas or discharging treated wastewater, and is used for introducing gas into the wastewater oxidation device. The other end of the air inlet pipeline can be connected with an air source 1. The gas rotameter 2 is used to control the amount and speed of intake air. The inlet valve 3 is used to control the opening and closing of the inlet line and may be a conventional inlet valve.

According to the oxidation system of wastewater of the present invention, as shown in fig. 1, the water outlet unit comprises a water outlet pump 15, a water outlet pipeline, and a water outlet valve 13 and an optional vacuum pressure gauge 14 which are arranged on the water outlet pipeline, the water outlet pipeline is connected with a port 5 of the oxidation device of wastewater for introducing gas or discharging treated wastewater, firstly, the gas is introduced into the oxidation device to contact with wastewater for oxidation treatment, and secondly, the treated wastewater discharged from the oxidation device of wastewater is received and conveyed to a water storage device or a discharge device. The outlet valve 13 is used for controlling the opening and closing of the water inlet pipeline, and may be a common outlet valve. The vacuum pressure gauge 14 is used for reading the pressure of the gas during the intake. When the water outlet valve 13 is opened and the air inlet valve 3 is closed, the water outlet pipeline is used for discharging the treated wastewater; when the inlet valve 3 is open and the outlet valve 13 is closed, the outlet line is used for introducing gas, wherein the two functions are performed alternately.

According to the oxidation system of waste water of the present invention, preferably, as shown in fig. 1, the system further comprises a three-way valve 4, wherein a first end of the three-way valve 4 is connected with an air inlet pipeline, a second end of the three-way valve is connected with the water outlet pipeline, a third end of the three-way valve is connected with a port 5 of the oxidation device of waste water for introducing air or discharging treated waste water through a pipeline, and three outlets can be integrated together through the three-way valve, so that ventilation or drainage can be realized through the alternate start and stop of a ventilation pipeline valve and a drainage pipeline valve more conveniently and safely. The three-way valve may be a common three-way valve.

According to the wastewater oxidation system, when the wastewater oxidation system is in an operation state, the air pump and the water outlet pump alternately operate, when the air pump operates, the water outlet pump is closed, the air inlet valve on the air inlet pipeline is opened, and the water outlet valve on the water outlet pipeline is closed; when the water outlet pump runs and the air pump stops, the air inlet valve on the air inlet pipeline is closed, and the water outlet valve on the water outlet pipeline is opened, so that the porous membrane alternately performs the functions of bubble generation and filtration. When the air pump and the water outlet pump are operated alternately, the sewage outlet 17, preferably the sewage valve 18, is closed.

According to the wastewater oxidation system of the present invention, when the treatment capacity of the wastewater oxidation apparatus reaches a certain level (for example, when the discharge requirement of the treated wastewater cannot be satisfied) or the transmembrane pressure difference of the porous membrane rises to a certain level (for example, when the filtration requirement cannot be satisfied or the filtration effect cannot be achieved), the wastewater oxidation apparatus needs to be cleaned and the pollution discharge treatment is performed. The blowdown valve 18 is opened, the air pump and the air inlet valve 3 are opened, the gas rotameter 2 is adjusted, the water inlet pump 10 is opened, water can be fed into the device to be various cleaning liquids, the water outlet valve 13 is closed, the blowdown port 17 is opened after the cleaning liquids stay in the device for a period of time, the blowdown valve 18 is preferably opened, dirt carrying the porous membrane and the surface of the vacuum ultraviolet light source (sleeve) is discharged from the blowdown port 17, and therefore cleaning and blowdown in the wastewater oxidation device are achieved. The cleaning solution may be any of various cleaning solutions suitable for cleaning an oxidation apparatus for wastewater, and may be one or more selected from an inorganic acid cleaning solution, an inorganic alkali cleaning solution, and an organic solvent cleaning solution.

According to the system for oxidizing waste water of the present invention, the oxidation apparatus for waste water may be one, or a combination of two or more. When the number of the wastewater oxidation apparatuses is two or more, the wastewater oxidation apparatuses may be connected in series, may be connected in parallel, or may be a combination of series connection and parallel connection. The serial connection means that the effluent of the oxidation device of the previous wastewater is used as the influent of the oxidation device of the next wastewater, so that multi-stage treatment is formed, and the wastewater treatment effect is further improved; the parallel connection means that the oxidation devices of the waste water have no material flow exchange but have the same waste water source, so that multi-machine parallel treatment is formed, and the treatment capacity of the system is further improved. When the serial connection and the parallel connection are combined for use, the wastewater oxidation devices can be divided into a plurality of groups, the groups are connected in parallel, and the wastewater oxidation devices in each group are connected in series; or a plurality of groups can be connected in series, and the wastewater oxidation devices in each group are connected in parallel.

According to a second aspect of the present invention, there is provided an oxidation process for advanced wastewater treatment, wherein the process is carried out in an apparatus for oxidation of wastewater according to the first aspect of the present invention, comprising feeding wastewater and optionally a catalyst into an oxidation zone through a water inlet under irradiation of a vacuum ultraviolet light source, and introducing a gas into a filtration separation zone through a port for introducing a gas or discharging treated wastewater, the gas being subjected to gas distribution through a porous membrane and then being fed into the oxidation zone to contact with the wastewater for oxidation treatment; and after the treatment is finished, stopping introducing the gas, filtering the treated wastewater by the porous membrane, then entering a filtering separation section, and discharging the gas or the treated wastewater by using an outlet discharge device.

According to the method of the present invention, the introduction of gas and the discharge of treated wastewater are alternately performed, and the discharge of treated wastewater is stopped while the introduction of gas is continued; when the treated wastewater was discharged, the introduction of gas was stopped. The number of times of the alternate operation is not particularly limited, and may be one time or multiple times, so as to achieve the final wastewater treatment effect and meet the wastewater discharge requirement. In order to ensure that no liquid leakage occurs in the wastewater treatment process and the safety of the treatment process is ensured, when gas is introduced and treated wastewater is discharged alternately, the blowdown through the blowdown port is stopped, namely, the blowdown port is closed, and preferably, the blowdown valve is closed.

According to a fourth aspect of the present invention, the present invention provides an oxidation method for advanced wastewater treatment, wherein the method is performed in the oxidation system for wastewater according to the third aspect of the present invention, and comprises the steps of starting a water inlet pump, feeding wastewater and an optional catalyst added through a catalyst adding unit into an oxidation section of an oxidation apparatus for wastewater through a water inlet, starting a vacuum ultraviolet light source, an air pump and an air inlet valve on an air inlet pipeline, closing a water outlet pump and a water outlet valve on a water outlet pipeline, introducing gas into a filtration separation section through a port for introducing gas or discharging treated wastewater, and allowing the gas to enter the oxidation section after gas distribution through a porous membrane and contact with the wastewater for oxidation treatment; after the treatment is finished, the air pump and the air inlet valve on the air inlet pipeline are closed, the water outlet pump and the water outlet valve on the water outlet pipeline are opened, and the treated wastewater enters the filtering and separating section after being filtered by the porous membrane and is discharged out of the system.

According to the method of the invention, in order to ensure that no leakage occurs during the treatment of the waste water and to ensure the safety of the treatment process, the drain, preferably the drain valve, is closed while the introduction of gas and the discharge of filtered waste water are performed alternately. The number of times of the alternate operation is not particularly limited, and may be one time or multiple times, so as to achieve the final wastewater treatment effect and meet the wastewater discharge requirement.

According to the method of the second and fourth aspects of the present invention, the inventors of the present invention found that the vacuum ultraviolet light source is capable of simultaneously irradiating vacuum ultraviolet waves of 200nm or less and short-wavelength ultraviolet waves of 200nm or more, preferably, the wavelength of the vacuum ultraviolet waves is 185nm and the wavelength of the short-wavelength ultraviolet waves is 254 nm. On one hand, the irradiation of vacuum ultraviolet band (less than or equal to 200nm) with water absorption characteristic can directly generate hydroxyl radical OH, when no catalyst is added, the introduced gas is preferably ozone or oxygen-containing gas, the oxygen-containing gas can react to generate ozone by absorbing the irradiation of the vacuum ultraviolet band, and the strong oxidizing property of the hydroxyl radical OH and the ozone enables the process to have the characteristic of more effectively degrading the organic matters which are difficult to be biodegraded in the industrial wastewater. On the other hand, the light source residual waveband ultraviolet light (the wavelength is more than 200nm, and the preferable short wavelength ultraviolet wave is 254nm) can be coupled with different catalysts to form a homogeneous photocatalytic reaction system, so that the biodegradability of the wastewater is further improved or the removal of COD of the wastewater is directly realized. Therefore, the vacuum ultraviolet light catalytic oxidation is a novel and green ultraviolet light catalytic process which can realize the advanced treatment of the organic pollutants difficult to degrade in the wastewater and improve the advanced oxidation treatment efficiency of the wastewater.

According to the method of the invention, in order to obtain higher COD removal rate, when the gas is introduced into the wastewater to contact with the wastewater for oxidation treatment, the gas is irradiated by a vacuum ultraviolet light source or under the combined action of the irradiation of the vacuum ultraviolet light source and a catalyst.

According to the method, when gas is contacted with the wastewater under the irradiation of a vacuum ultraviolet light source or under the irradiation of the vacuum ultraviolet light source and in the presence of a catalyst simultaneously to carry out the oxidation treatment of the wastewater, the construction of various advanced oxidation systems can be realized in an oxidation device/an oxidation system of the wastewater by adjusting the types of the introduced gas and the homogeneous catalyst. Particularly, when the introduced gas is air and/or oxygen, the vacuum ultraviolet light source can simultaneously radiate ultraviolet light with the wavelength less than or equal to 200nm (preferably 185nm) and ultraviolet light with the wavelength more than 200nm (preferably 254nm), and the air and/or the oxygen entering the oxidation device of the waste water can generate ozone under the irradiation of the wave band less than or equal to 200nm (preferably 185nm) of the vacuum ultraviolet light source, so that a vacuum ultraviolet/ozone advanced oxidation system of the air and/or the oxygen source is constructed.

According to a preferred embodiment of the present invention, when the vacuum ultraviolet light source is turned on and the gas is contacted with the wastewater without adding the catalyst to perform the oxidation treatment of the wastewater, when the gas is ozone and/or oxygen-containing gas, a vacuum ultraviolet light/ozone system is constructed in the wastewater oxidation device/wastewater oxidation system.

According to a preferred embodiment of the present invention, when the vacuum ultraviolet light source is turned on, and a catalyst is added to contact gas with wastewater to perform oxidation treatment of wastewater, when the introduced gas is nitrogen and/or a group zero gas and the homogeneous catalyst is hydrogen peroxide, fenton reagent or persulfate, respectively, the systems constructed in the wastewater oxidation apparatus/wastewater oxidation system are vacuum ultraviolet light/hydrogen peroxide, vacuum ultraviolet light/fenton reagent and vacuum ultraviolet light/persulfate systems, respectively.

According to a preferred embodiment of the present invention, when the vacuum ultraviolet light source is turned on and the catalyst is added to contact the gas with the wastewater to perform the oxidation treatment of the wastewater, when the introduced gas is ozone and/or an oxygen-containing gas and the homogeneous catalyst is hydrogen peroxide, fenton reagent or persulfate, respectively, the systems constructed in the wastewater oxidation apparatus/wastewater oxidation system are vacuum ultraviolet light/ozone/hydrogen peroxide, vacuum ultraviolet light/ozone/fenton reagent and vacuum ultraviolet light/ozone/persulfate systems, respectively.

According to the method of the second and fourth aspects of the present invention, the vacuum ultraviolet light source may simultaneously irradiate ultraviolet light of 200nm or less and 200nm or more, the latter having a luminous intensity, generally expressed as radiant power, greater than the former. Therefore, it is further preferable that, in order to further improve the treatment efficiency and treatment effect of wastewater, the ratio of the radiation power of the vacuum ultraviolet wave irradiated at 200nm or less to the radiation power of the short-wavelength ultraviolet wave irradiated at 200nm or more is 1:3 to 8, more preferably 1:4 to 6.

According to the methods of the second and fourth aspects of the present invention, in the treatment process, depending on the nature of the wastewater and the desired treatment effect, a catalyst may or may not be added, as described above. In a preferred embodiment, a catalyst is added to the oxidation apparatus of wastewater during the treatment, and the catalyst may be any of various catalysts capable of promoting the catalytic oxidation of wastewater, and preferably, the catalyst is selected from one or more of hydrogen peroxide, fenton's reagent, persulfate, sulfite, and hypochlorous acid. The amount of the catalyst may be selected conventionally, and for example, the amount of the catalyst may be 10 to 1000mg/L based on the total amount of the wastewater. The method of the invention has obviously improved treatment efficiency, and can obtain good treatment effect even at lower catalyst dosage. According to the method of the present invention, the amount of the catalyst is preferably 50 to 100mg/L, more preferably 80 to 100mg/L, based on the total amount of the wastewater. The catalyst is preferably used in the form of a solution (e.g. an aqueous solution), for example in the form of an aqueous solution having a mass concentration of 20 to 50%, preferably 25 to 40%.

According to the method of the second and fourth aspects of the present invention, the gas introduced into the oxidation apparatus for wastewater through the port for introducing gas or discharging treated wastewater is mainly used for the wastewater introduced into the oxidation stage through the pore passages of the porous membrane, fine bubbles are generated in the wastewater, and the gas-liquid contact area is increased. The type of the gas is not particularly limited, and may be a gas that can generate microbubbles without additionally introducing contaminants into the wastewater. Preferably, the oxidation treatment effect of the wastewater is improved by using a gas which can generate microbubbles and promote the catalytic oxidation of the wastewater by combining a vacuum ultraviolet light source or a vacuum ultraviolet light source and a catalyst. Specifically, the gas is one or a combination of more than two of oxygen-containing gas, nitrogen, ozone and group zero gas, and the oxygen-containing gas is pure oxygen and/or air.

Preferably, according to an embodiment of the present invention, when a gas is contacted with wastewater under irradiation of a vacuum ultraviolet light source and in the presence of a catalyst to perform oxidation treatment of wastewater, the gas is one or a combination of two or more of an oxygen-containing gas, nitrogen, ozone and a group zero gas;

preferably, according to another embodiment of the present invention, when the gas is contacted with the wastewater only under the irradiation of the vacuum ultraviolet light source to perform the oxidation treatment of the wastewater, the gas is one or a combination of two or more of oxygen-containing gas and ozone, and the oxygen-containing gas is pure oxygen and/or air.

According to the method of the second and fourth aspects of the invention, the rate of introduction of the gas may be conventionally selected. Preferably, the gas is introduced at a rate of 50 to 500mL/min, so that a better sewage treatment effect can be obtained, and the service life of the porous membrane can be further prolonged. More preferably, the gas is introduced at a rate of 100-300 mL/min.

According to the method of the second and fourth aspects of the present invention, the oxidation treatment of the wastewater is preferably carried out in a batch operation, and therefore, the present invention is not particularly limited with respect to the water feed rate of the wastewater.

According to the method of the second and fourth aspects of the invention, wastewater from various sources can be treated, and the method is particularly suitable for advanced oxidation treatment of various industrial wastewater. For example, the industrial wastewater can be secondary biochemical effluent, acrylic fiber wastewater, reverse osmosis concentrated water, benzene-containing wastewater and the like.

The method of the present invention is described in detail below with reference to fig. 1. As shown in fig. 1, the water inlet line of the water inlet unit is turned on to pump the water 10. The wastewater to be treated enters the oxidation section of the hollow cylinder 8 through the water inlet pipeline and the water inlet 12 of the wastewater oxidation device, optionally, a catalyst is added into the water inlet pipeline through the catalyst adding unit 11, and the catalyst enters the oxidation section of the hollow cylinder 8 along with the wastewater to be treated through the water inlet pipeline and the water inlet 12 of the wastewater oxidation device. During the introduction of the waste water, the outlet valve 13 of the outlet unit is closed as well as the waste outlet 17 and the waste valve 18. When the liquid level of the wastewater to be treated rises to about 5-10mm from the water inlet 12, the water inlet pump 10 of the water inlet unit is turned off.

The vacuum ultraviolet light source 9 is started, simultaneously, an air inlet pump of an air source 1 of an air conveying unit and an air inlet valve 3 are started, a gas rotameter 2 is adjusted, air enters a filtering separation section of an oxidation device of wastewater from the air source 1 through the air conveying unit and a port 5 for introducing air or discharging treated wastewater of the oxidation device of the wastewater through a three-way valve 4, the air enters an oxidation section on the upper part of a porous membrane through micropores of the porous membrane to form micro bubbles, and the micro bubbles move upwards against the direction of a gravity field and are continuously contacted and mixed with wastewater to be treated in the process of the upwards movement of the bubbles. On one hand, the fine bubbles strengthen hydraulic disturbance and improve the mass transfer efficiency; on the other hand, different advanced oxidation reaction systems can be constructed by changing the kind of gas.

After the wastewater treatment is finished, the air inlet pump of the air source 1 of the air conveying unit and the air inlet valve 3 are closed, the water outlet valve 13 and the water outlet pump 15 of the water outlet unit are opened, the interior of the filtering and separating section of the wastewater oxidation device is changed into a negative pressure state, the treated wastewater enters the filtering and separating section below the porous membrane 7 after being filtered by the porous membrane 7 from the oxidation section above the porous membrane 7, and then is discharged through the oxidation device of the port 5 for introducing air or discharging the treated wastewater, so that the porous membrane is backwashed while the filtration and the discharge of the oxidized wastewater are realized. The treated wastewater enters a water outlet pipeline of the water outlet unit through the three-way valve 4 and is discharged out of the system through the water outlet pipeline. During the discharge of the treated waste water, the sewage drain 17 and the sewage drain valve 18 are closed. At this time, the gas distributor and the filtering and separating function of the porous membrane 7 realize advanced oxidation and advanced filtration treatment of the industrial wastewater in the wastewater oxidation apparatus.

According to the invention, the operation sequence of the wastewater oxidation system is preferably water inlet, water inlet stopping, air source air inlet (the vacuum ultraviolet lamp is started and/or the catalyst is added along with the water inlet), wastewater oxidation treatment, air source air inlet stopping and water outlet filtering. At the end of a batch, the above steps may be repeated to begin the next batch depending on the extent of wastewater treatment and/or discharge requirements.

The present invention will be described in detail below by way of examples.

In the following examples, the COD of the wastewater was measured by the dichromate method (GB 11914-89). The BOD of the wastewater is measured by a dilution inoculation method (GB/T7488-1987).

COD removal rate is 100 (COD content in the wastewater before treatment-COD content in the wastewater after treatment)/COD content in the wastewater before treatment.

Examples 1-9 industrial wastewater was treated using the oxidation system for wastewater described in fig. 1.

(1) In the oxidation device of waste water, the hollow cylinder body, the upper end cover and the lower end cover are of an integrated structure and are all made of stainless steel materials. The inner space of the hollow cylinder body is equal in diameter, the inner diameter is 80mm, and the vertical distance from the top end of the upper end cover of the hollow cylinder body to the bottom end of the lower end cover is 1100 mm. The end surfaces of the upper end cover and the lower end cover of the hollow cylinder body are arc surfaces protruding outwards to form hemispherical surfaces respectively.

(2) The porous membrane was a flat ceramic membrane (available from Ming dynasty, Japan) having an outer diameter of 80mm, an average pore diameter of 0.1 μm, and a porosity of 50%. The flat ceramic membrane divides the hollow cylinder into two independent spaces, the upper part is an oxidation section, and the lower part is a filtration and separation section. The upper end face and the lower end face of the flat ceramic membrane are respectively provided with flange plates which can be matched with each other, the flat ceramic membrane and the hollow cylinder body are connected together through bolts, and a rubber sealing gasket is arranged at the joint part. The ratio of the height of the oxidation section to the height of the hollow cylinder is 0.9:1 by taking the bottom end of the hollow cylinder as a reference.

(3) The water inlet is arranged at the upper part of the oxidation section, the ratio of the height of the water inlet to the height of the hollow cylinder is 0.9:1 by taking the bottom end of the hollow cylinder as a reference; the sewage draining port is arranged at the lower part of the oxidation section, and the lower tangent plane of the pipeline of the sewage draining port and the upper surface of the flat ceramic membrane are positioned on the same plane.

(4) The port for introducing gas or discharging treated wastewater is provided at the bottom end (lowest point of the lower end surface) of the hollow cylinder.

(5) The vacuum ultraviolet light source is a straight tube vacuum ultraviolet lamp with an integrated structure, namely the straight tube vacuum ultraviolet lamp is arranged in a quartz sleeve, the diameter of the vacuum ultraviolet lamp is 15mm, and the outer diameter of the quartz sleeve is 23 mm. The peripheral side wall of the upper end of the sleeve is fixedly connected with the opening on the upper end cover in a bolt connection mode. The vacuum ultraviolet lamp is a 185nm/254nm composite tube, the rated power is 80W (the ratio of the radiation power of vacuum ultraviolet waves with the irradiation less than or equal to 200nm to the radiation power of short wavelength ultraviolet waves with the irradiation more than 200nm is 1:5), the tube voltage is AC77V, the tube current is 1.2A, the length is 950mm, and the vertical distance between the bottom of the straight tube vacuum ultraviolet lamp tube of the integrated structure and the flat-plate ceramic membrane is 10 mm.

The industrial wastewater to be treated is taken from the effluent of a biochemical unit of a certain refinery, the COD is 72.4mg/L, the BOD is 9.5mg/L, and the BOD/COD is about 0.13.

Example 1

Starting a water inlet pump, enabling the industrial wastewater to be treated to enter an oxidation section in a hollow cylinder of the wastewater oxidation device from a water inlet of a water inlet unit (without adding a homogeneous catalyst), and closing a water outlet valve, a sewage outlet and a sewage valve of a water outlet unit in the process of introducing the wastewater. When the liquid level of the wastewater to be treated rises to be 5-10mm away from the water inlet, the water inlet pump of the water inlet unit is closed.

Opening a straight tube vacuum ultraviolet lamp with an integrated structure, opening an air inlet pump and an air inlet valve of a nitrogen gas source of a gas conveying unit, adjusting a gas rotor flow meter until the gas flow is 100mL/min, enabling the gas to enter a filtering and separating section of the wastewater oxidation device, enabling the gas to enter an upper oxidation section through micropores of a flat ceramic membrane to form micro bubbles, and enabling the micro bubbles to be in continuous contact with and mixed with the industrial wastewater to be treated. After 30min treatment in the wastewater oxidation device, the nitrogen source and the air inlet valve are closed. Opening a water outlet valve and a water outlet pump, changing the interior of a filtering and separating section of the wastewater oxidation device into a negative pressure state, filtering the treated wastewater by using a flat ceramic membrane, then feeding the filtered wastewater into a filtering and separating section below, discharging the wastewater oxidation device, and determining the water quality condition of effluent as follows: COD was 65.0mg/L, BOD was 16.6mg/L, and BOD/COD was about 0.26.

Comparative example 1

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started at the same time, the industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 weight percent), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integrated structure is closed, an air inlet pump and an air inlet valve of a nitrogen gas source of a gas conveying unit are started, a gas rotor flow meter is adjusted until the gas flow is 100mL/min, and after the wastewater is treated for 30min in the oxidation device of the wastewater, the effluent water quality condition: COD was 72.0mg/L, BOD was 10.0mg/L, and BOD/COD was about 0.14.

Example 2

The same method as that of example 1 is adopted to treat the industrial wastewater with the same water quality as that of example 1, except that the gas source is oxygen, the gas flow is 100mL/min, and after the treatment for 30min in the wastewater oxidation device, the effluent water quality is measured as follows: COD was 62.0mg/L, BOD was 21.1mg/L, and BOD/COD was about 0.34.

Comparative example 2

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started at the same time, the industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 weight percent), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integrated structure is closed, an air inlet pump and an air inlet valve of an oxygen gas source of a gas conveying unit are started, a gas rotor flow meter is adjusted until the gas flow is 100mL/min, and after the wastewater is treated for 30min in the oxidation device of the wastewater, the effluent water quality condition: COD was 69.4mg/L, BOD was 10.8mg/L, and BOD/COD was about 0.16.

Example 3

The same method as that of example 1 is adopted to treat the industrial wastewater with the same water quality as that of example 1, except that a water inlet pump is started and a medicament adding unit is started at the same time, the industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 weight percent), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of a water inlet unit, and after the wastewater is treated in the oxidation device of the wastewater for 30min, the water quality condition of effluent is determined as follows: COD was 45.0mg/L, BOD was 18.2mg/L, and BOD/COD was about 0.40.

Example 4

The same method as that of example 1 is adopted to treat the industrial wastewater with the same water quality as that of example 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and a homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 wt%), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, an air source is oxygen, the air flow is 100mL/min, and after the wastewater is treated in the oxidation device for 30min, the water quality condition of effluent is measured as follows: COD was 28.5mg/L, BOD was 8.5mg/L, and BOD/COD was about 0.30.

Example 5

The same method as that of example 1 is adopted to treat the industrial wastewater with the same water quality as that of example 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 wt%), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, an air source is air, the gas flow is 100mL/min, and after the wastewater is treated in the oxidation device for 30min, the water quality condition of effluent is measured as follows: COD was 35.6mg/L, BOD was 9.0mg/L, and BOD/COD was about 0.25.

Comparative example 3

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started at the same time, the industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 weight percent), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integrated structure is closed, an air inlet pump and an air inlet valve of an ozone source of an air conveying unit are started, a gas rotor flow meter is adjusted to control the gas flow to be 100mL/min, so that the ozone adding concentration is 50mg/L, and after the wastewater is treated for 30min in the oxidation device of the wastewater, the water quality: COD was 49.3mg/L, BOD was 17.3mg/L, and BOD/COD was about 0.35.

Comparative example 4

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and a Fenton reagent (the industrial wastewater to be treated is used in the form of aqueous hydrogen peroxide (30 weight percent), the concentration of hydrogen peroxide in the wastewater is 30mg/L, the industrial wastewater to be treated is used in the form of aqueous ferrous sulfate (25 weight percent) and the concentration of ferrous sulfate in the wastewater is 80mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integrated structure is closed, an air inlet pump and an air inlet valve of a nitrogen gas source of a gas conveying unit are started, a gas rotor flow meter is adjusted until the gas flow is 100mL/min, and after the wastewater is treated in the oxidation device of the wastewater for, the effluent quality was measured as follows: COD was 58.1mg/L, BOD was 25.3mg/L, and BOD/COD was about 0.44.

Example 6

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and a homogeneous catalyst potassium persulfate (used in the form of a potassium persulfate aqueous solution (40 weight percent), and the concentration of the potassium persulfate in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integrated structure is started, an air inlet pump and an air inlet valve of a nitrogen gas source of an air conveying unit are started, a gas rotor flow meter is adjusted until the gas flow is 100mL/min, and after 30min treatment in the oxidation device of the wastewater, the effluent water quality condition is determined as follows: COD was 40.2mg/L, BOD was 17.2mg/L, and BOD/COD was about 0.43.

Example 7

The same apparatus and system for oxidation of wastewater as in examples 1-6 were used except that the ceramic membrane had an average pore size of 20 μm and a porosity of 50%.

The same method as that of example 1 is adopted to treat the industrial wastewater with the same water quality as that of example 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and a homogeneous catalyst hydrogen peroxide (used in the form of aqueous hydrogen peroxide (30 wt%), and the concentration of the hydrogen peroxide in the wastewater is 30mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater from a water inlet of the water inlet unit, an air source is oxygen, the gas flow is 100mL/min, and after the treatment for 30min in the oxidation device, the water quality of effluent is measured as follows: COD was 46.3mg/L, BOD was 16.7mg/L, and BOD/COD was about 0.36.

Example 8

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that an air source is ozone, a gas rotameter is adjusted to control the gas flow rate to be 100mL/min, so that the adding concentration of the ozone is 50mg/L, and after the wastewater is treated in an oxidation device for 30min, the water quality condition of effluent is measured as follows: COD was 43.5mg/L, BOD was 17.0mg/L, and BOD/COD was about 0.39.

Example 9

The same method as that of the embodiment 1 is adopted to treat the industrial wastewater with the same water quality as that of the embodiment 1, except that a water inlet pump is started, a medicament adding unit is started, the industrial wastewater to be treated and a Fenton reagent (the industrial wastewater to be treated is used in the form of aqueous hydrogen peroxide (30 weight percent), the concentration of hydrogen peroxide in the wastewater is 30mg/L, the industrial wastewater to be treated is used in the form of aqueous ferrous sulfate (25 weight percent) and the concentration of ferrous sulfate in the wastewater is 80mg/L) enter an oxidation section in a hollow cylinder of an oxidation device of the wastewater, after the water inlet is finished, a straight tube vacuum ultraviolet lamp with an integral structure is started, an air inlet pump and an air inlet valve of a nitrogen gas source of a gas conveying unit are started, a gas rotor flow meter is adjusted until the gas flow is 100mL/min, and after the wastewater is treated in the oxidation device of the wastewater for, the effluent quality was measured as follows: COD was 32.2mg/L, BOD was 9.0mg/L, and BOD/COD was about 0.28.

Example 10 industrial wastewater was treated using the oxidation system for wastewater as described in fig. 2, and unlike examples 1 to 9, the number of vacuum ultraviolet light sources in the oxidation apparatus for wastewater was 4.

(1) In the oxidation device of waste water, the hollow cylinder body, the upper end cover and the lower end cover are of an integrated structure and are all made of stainless steel materials. The inner space of the hollow cylinder body is equal in diameter, the inner diameter is 150mm, and the vertical distance from the top end of the upper end cover of the hollow cylinder body to the bottom end of the lower end cover is 1100 mm. The end surfaces of the upper end cover and the lower end cover of the hollow cylinder body are arc surfaces protruding outwards to form hemispherical surfaces respectively.

(2) The porous membrane was a flat ceramic membrane (available from Ming dynasty, Japan) having an outer diameter of 150mm, an average pore diameter of 0.1 μm, and a porosity of 50%. The flat ceramic membrane divides the hollow cylinder into two independent spaces, the upper part is an oxidation section, and the lower part is a filtration and separation section. The upper end face and the lower end face of the flat ceramic membrane are respectively provided with flange plates which can be matched with each other, the flat ceramic membrane and the hollow cylinder body are connected together through bolts, and a rubber sealing gasket is arranged at the joint part. The ratio of the height of the oxidation section to the height of the hollow cylinder is 0.85:1, based on the bottom end of the hollow cylinder.

(3) The water inlet is arranged at the upper part of the oxidation section, the ratio of the height of the water inlet to the height of the hollow cylinder is 0.85:1 by taking the bottom end of the hollow cylinder as a reference; the sewage draining port is arranged at the lower part of the oxidation section, and the lower tangent plane of the pipeline of the sewage draining port and the upper surface of the flat ceramic membrane are positioned on the same plane.

The industrial wastewater to be treated was the same as in examples 1 to 10.

Example 10

Starting a water inlet pump and simultaneously starting a medicament adding unit, feeding industrial wastewater to be treated and homogeneous catalyst hydrogen peroxide (the concentration of hydrogen peroxide is 30mg/L) into an oxidation section in a hollow cylinder of the wastewater oxidation device from a water inlet of the water inlet unit, and closing a water outlet valve, a sewage discharge port and a sewage discharge valve of a water outlet unit in the process of introducing the wastewater. When the liquid level of the wastewater to be treated rises to be 5-10mm away from the water inlet, the water inlet pump of the water inlet unit is closed. Opening a straight tube vacuum ultraviolet lamp with an integrated structure, opening an air inlet pump and an air inlet valve of an oxygen gas source of a gas conveying unit, adjusting a gas rotor flow meter until the gas flow is 300mL/min, enabling the gas to enter a filtering and separating section of the wastewater oxidation device, enabling the gas to enter an upper oxidation section through micropores of a flat ceramic membrane to form micro bubbles, and enabling the micro bubbles to be in continuous contact with and mixed with the industrial wastewater to be treated. After 12min treatment in the wastewater oxidation device, the oxygen gas source and the gas inlet valve are closed. Opening a water outlet valve and a water outlet pump, changing the interior of a filtering and separating section of the wastewater oxidation device into a negative pressure state, filtering the treated wastewater by using a flat ceramic membrane, then feeding the filtered wastewater into a filtering and separating section below, discharging the wastewater oxidation device, and determining the water quality condition of effluent as follows: COD was 21.2mg/L, BOD was 5.3mg/L, and BOD/COD was about 0.25.

TABLE 1

The results of examples 1 to 10 demonstrate that the apparatus and system for oxidizing wastewater according to the present invention can achieve a better treatment effect when used for treating industrial wastewater.

Specifically, as can be seen from comparison of example 1, comparative example 1 and example 3, under the same treatment conditions and with a nitrogen gas source, the COD removal rate of the wastewater is only 1% only in the presence of the catalyst hydrogen peroxide without irradiation of the vacuum ultraviolet light source, whereas the COD removal rate of the wastewater is increased to 10% under irradiation of the vacuum ultraviolet light source, and further, the COD removal rate of the wastewater is further increased to 38% under irradiation of the vacuum ultraviolet light source and the presence of the catalyst hydrogen peroxide.

Specifically, as can be seen from comparison of example 2, comparative example 2 and example 4, under the same treatment conditions and with the oxygen as the gas source, the COD removal rate of the wastewater is only 4% only in the presence of the catalyst hydrogen peroxide without irradiation of the vacuum ultraviolet light source, while the COD removal rate of the wastewater is increased to 14% under irradiation of the vacuum ultraviolet light source, and further, the COD removal rate of the wastewater is further increased to 61% under irradiation of the vacuum ultraviolet light source and the presence of the catalyst hydrogen peroxide. Furthermore, as can be seen from the comparison between example 5 and example 4, under the same treatment conditions and in the presence of the same catalyst, the COD removal rate of the wastewater is still high, namely 51%, when the gas source is changed from oxygen to air. Thus, it is demonstrated that the removal rate of COD can be significantly improved by subjecting the wastewater to catalytic oxidation treatment by contacting with oxygen-containing gas/ozone under vacuum ultraviolet irradiation, more preferably by contacting with oxygen-containing gas/ozone under vacuum ultraviolet irradiation and in the presence of a catalyst.

Specifically, as can be seen from comparison between examples 4 and 5 and comparative examples 3 and 4, although the effect of treating wastewater by catalytic oxidation using ozone and fenton oxidation directly is still sufficient, the catalytic oxidation effect of wastewater by air or oxidation in combination with a catalyst can be further significantly improved under irradiation of vacuum ultraviolet light according to the present invention.

Specifically, as can be seen from a comparison between example 8 and comparative example 3, the removal rate of the COD in the wastewater is significantly improved by the irradiation with only the vacuum ultraviolet light source under the condition of ozone introduction, compared with the treatment mode in which only the hydrogen peroxide catalyst is added.

Specifically, as can be seen from comparison between example 9 and comparative example 4, the removal rate of COD from wastewater was significantly improved by irradiation with vacuum ultraviolet light source and combination with fenton reagent under the condition of introducing nitrogen gas, compared with the treatment method in which only fenton reagent was added.

Further, as is clear from comparison between example 7 and example 1, the effect of treating wastewater can be further improved by using the porous membrane having preferable parameters.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. An oxidation device for waste water, which is characterized by comprising a hollow cylinder body with an upper end cover and a lower end cover, wherein the upper end cover and the lower end cover respectively seal the top end and the bottom end of the hollow cylinder body;

2. The apparatus of claim 1, further comprising one or more openings disposed on the upper end cap, and one or more vacuum ultraviolet light sources disposed in the oxidation zone, the vacuum ultraviolet light sources being disposed in a sleeve, the bottom end of the sleeve being closed, the peripheral sidewall of the upper end of the sleeve being fixedly connected to the openings disposed on the upper end cap;

preferably, the sleeve is a quartz sleeve;

further preferably, the sleeve and the vacuum ultraviolet light source are of an integrated structure.

3. The device according to claim 1, wherein the porous membrane has an average pore size of 0.1-50 μ ι η, preferably 0.5-10 μ ι η; the porosity is 40-50%;

more preferably, the porous membrane is a ceramic membrane.

4. The apparatus of any one of claims 1 to 3, wherein the ratio of the height of the oxidation zone to the height of the hollow cylinder, based on the bottom end of the hollow cylinder, is from 0.85 to 0.95: 1.

5. The apparatus according to any one of claims 1 to 3, wherein the water inlet is arranged at the upper part of the oxidation section, preferably, the ratio of the height of the water inlet to the height of the hollow cylinder is 0.8-0.9: 1;

the sewage draining outlet is arranged at the lower part of the oxidation section, and preferably, the ratio of the height of the sewage draining outlet to the height of the hollow cylinder is 0.1-0.2: 1; more preferably, the lower section of the pipe of the sewage draining outlet and the upper surface of the porous membrane are in the same plane; further preferably, the device is also provided with a drain valve for controlling the start and stop of the drain, and the drain valve is arranged on a pipeline connected with the drain.

6. The device according to claim 1, wherein the port for introducing gas or discharging treated wastewater is provided on a lower end cap, preferably at the bottom end of the hollow cylinder.

7. An oxidation method for advanced wastewater treatment, which is carried out in the wastewater oxidation device of any one of claims 1 to 6, and comprises the steps of feeding wastewater and an optional catalyst into an oxidation section through a water inlet under the irradiation of a vacuum ultraviolet light source, introducing gas into a filtering separation section through a port for introducing gas or discharging treated wastewater, and feeding the gas into the oxidation section after the gas is subjected to gas distribution through a porous membrane to be in contact with the wastewater for oxidation treatment; and after the treatment is finished, stopping introducing the gas, filtering the treated wastewater by the porous membrane, then entering a filtering separation section, and discharging the gas or the treated wastewater by using an outlet discharge device.

8. The method according to claim 7, wherein the introduction of gas and the discharge of treated wastewater are alternated, and the discharge of treated wastewater is stopped while the introduction of gas is continued; stopping introducing the gas when the treated wastewater is discharged;

the drain is closed, preferably the drain valve is closed, while the introduction of gas and the discharge of treated wastewater are alternated.

9. The method according to claim 7, wherein the vacuum ultraviolet light source is capable of simultaneously irradiating vacuum ultraviolet waves of less than or equal to 200nm and short wavelength ultraviolet waves of greater than 200nm, preferably the vacuum ultraviolet waves have a wavelength of 185nm and the short wavelength ultraviolet waves have a wavelength of 254 nm.

10. The method according to claim 9, wherein the ratio of the radiation power of the vacuum ultraviolet wave irradiated at 200nm or less to the radiation power of the short wavelength ultraviolet wave irradiated at 200nm or more is 1:3 to 8, preferably 1:4 to 6.

11. The method of claim 7, wherein the catalyst is selected from one or more of hydrogen peroxide, fenton's reagent, persulfate, sulfite, and hypochlorous acid;

preferably, the amount of the catalyst is 10 to 1000mg/L, more preferably 50 to 100mg/L, based on the total amount of the wastewater.

12. The method according to claim 7, wherein the gas is introduced at a rate of 50-500mL/min, preferably 100-300 mL/min.

13. The method according to any one of claims 7 to 12, wherein the gas is one or a combination of two or more of an oxygen-containing gas, nitrogen, ozone and a group zero gas, the oxygen-containing gas being pure oxygen and/or air;

preferably, when the gas is contacted with the wastewater under the irradiation of a vacuum ultraviolet light source and in the presence of a catalyst to carry out the oxidation treatment of the wastewater, the gas is one or the combination of more than two of oxygen-containing gas, nitrogen, ozone and a group zero gas;

preferably, when the gas is contacted with the wastewater only under the irradiation of the vacuum ultraviolet light source to carry out the oxidation treatment of the wastewater, the gas is one or the combination of more than two of oxygen-containing gas and ozone, and is more preferably ozone; the oxygen-containing gas is pure oxygen and/or air.

14. An oxidation system for wastewater, comprising a water inlet unit, a gas delivery unit, the wastewater oxidation apparatus of any one of claims 1 to 6, and a water outlet unit,

and the water outlet unit is an oxidation device for discharging the treated wastewater out of the wastewater.

15. The system of claim 14, wherein,

the water inlet unit comprises a water inlet pump, a water inlet pipeline and a catalyst adding unit which is optionally arranged on the water inlet pipeline, and the water inlet pipeline is connected with a water inlet of the wastewater oxidation device;

the gas conveying unit comprises a gas pump, a gas inlet pipeline, a gas rotor flow meter and a gas inlet valve, wherein the gas rotor flow meter and the gas inlet valve are arranged on the gas inlet pipeline;

the water outlet unit comprises a water outlet pump, a water outlet pipeline, a water outlet valve and an optional vacuum pressure gauge, wherein the water outlet valve and the optional vacuum pressure gauge are arranged on the water outlet pipeline;

preferably, the system further comprises a three-way valve, wherein a first end of the three-way valve is connected with the air inlet pipeline, a second end of the three-way valve is connected with the water outlet pipeline, and a third end of the three-way valve is connected with a port of the wastewater oxidation device for introducing gas or discharging treated wastewater through a pipeline.

16. The system of claim 15, wherein the air pump and the water outlet pump operate alternately, and when the air pump is turned on and the water outlet pump is turned off, an air inlet valve on the air inlet line is opened and a water outlet valve on the water outlet line is closed; when the water outlet pump runs and the air pump is closed, the air inlet valve on the air inlet pipeline is closed, and the water outlet valve on the water outlet pipeline is opened;

and when the air pump and the water outlet pump alternately operate, closing a sewage discharge port, preferably closing a sewage discharge valve.

17. The system of claim 15 or 16, wherein the wastewater oxidation devices are two or more, and the two or more wastewater oxidation devices are connected in parallel, in series, or in a combination of parallel and series.

18. An oxidation method for advanced wastewater treatment, which is carried out in the wastewater oxidation system of any one of claims 14 to 17, and comprises the steps of starting a water inlet pump, feeding wastewater and an optional catalyst added through a catalyst feeding unit into an oxidation section of a wastewater oxidation device through a water inlet, starting a vacuum ultraviolet light source, an air pump and an air inlet valve on an air inlet pipeline, closing a water outlet pump and a water outlet valve on a water outlet pipeline, introducing gas into a filtering separation section through a port for introducing gas or discharging treated wastewater, and allowing the gas to enter the oxidation section after gas distribution through a porous membrane to contact with the wastewater for oxidation treatment; after the treatment is finished, the air pump and the air inlet valve on the air inlet pipeline are closed, the water outlet pump and the water outlet valve on the water outlet pipeline are opened, and the treated wastewater enters the filtering and separating section after being filtered by the porous membrane and is discharged out of the system.

19. A method according to claim 18, wherein the drain is closed, preferably the drain valve is closed, while the gas feeding and the draining of the filtered waste water are alternated.

20. The method of claim 18, wherein the vacuum ultraviolet light source is capable of simultaneously irradiating vacuum ultraviolet waves less than or equal to 200nm and short wavelength ultraviolet waves greater than 200nm, preferably the vacuum ultraviolet waves have a wavelength of 185nm and the short wavelength ultraviolet waves have a wavelength of 254 nm.

21. The method according to claim 20, wherein the ratio of the radiation power of the vacuum ultraviolet wave irradiated at 200nm or less to the radiation power of the short wavelength ultraviolet wave irradiated at 200nm or more is 1:3 to 8, preferably 1:4 to 6.

22. The method of claim 18, wherein the catalyst is selected from one or more of hydrogen peroxide, fenton's reagent, persulfate, sulfite, and hypochlorous acid;

23. The method according to claim 18, wherein the gas is introduced at a rate of 50-500mL/min, preferably 100-300 mL/min.

24. The method of any one of claims 18-23, wherein the gas is one or a combination of two or more of an oxygen-containing gas, nitrogen, ozone, and a group zero gas, the oxygen-containing gas being pure oxygen and/or air;