CN1211295C - Fixed membrane optocatalytic oxidation water treating system - Google Patents

Abstract

The present invention relates to a novel fixed membrane photocatalysis oxidation water treatment system, particularly to a device capable of removing organic matter in water and waste water. The device comprises a water tank (1), an intake pump (6), a chemical oxidation reactor (20), a photocatalysis oxidation reactor (12) and a flow meter (15) which are connected by a pipeline, wherein photocatalyst of the photocatalysis oxidation reactor (12) can be instantly formed and instantly back washed off, and the thickness, the hole diameter and the formula can be freely adjusted. The present invention realizes the combination use of chemical oxidation, photooxidation and photocatalysis oxidation, and solves the immobilization problem of the photocatalyst. Additionally, the photocatalyst can be recovered, the operating cost is low, the treatment efficiency is good, the structure is reasonable, the maintenance is convenient, and the application range is wide. The device can be independently used for treating various kinds of water and waste water, and can also be used in pretreatment or terminal treatment in flow paths of conventional water treatment, and yielding water can be directly discharged or be recycled. The device is especially suitable for the treatment of hard degraded organic waste water and organic waste water with high concentration and high chrominance, the advanced treatment of potable water and the terminal treatment and the pretreatment of water with high purity.

Description

An instant film-forming photocatalytic oxidation water treatment system

Technical field

The invention relates to a novel fixed-film photocatalytic oxidation water treatment device. The invention can be widely used to remove organic matter in water and waste water, and is especially suitable for the treatment of various refractory organic waste water, high-concentration and high-color organic waste water, advanced treatment of drinking water, terminal treatment and pretreatment of high-purity water, etc.

Background technique

In recent decades, with the rapid development of organic chemical, petrochemical, pharmaceutical, pesticide and other industries, the types and output of organic compounds are increasing day by day. And through various ways into the human environment, especially the water environment, it is estimated that there are about 96,000 kinds of organic matter in the water environment. They are very harmful to the environment. Whether it is river, river, lake water or waste water or tap water, the organic matter pollution in it has become the main problem of water pollution. Therefore, the removal of organic pollutants in water has become one of the primary tasks of water treatment. Especially in landfill leachate, pharmaceutical wastewater, coking wastewater, papermaking wastewater, petrochemical wastewater and other high-concentration and refractory organic wastewater, the organic matter and ammonia nitrogen concentration are very high, even toxic, and have poor biodegradability. Traditional biochemical treatment is often difficult Get the desired effect.

Photocatalytic oxidation begins with the excited transition of electrons in semiconductors under light irradiation, most commonly UV/ _TiO2 . It has been proved that if there is sufficient reaction time, photocatalytic oxidation can completely mineralize organic substances into simple inorganic substances such as CO ₂ and H ₂ O. If additional oxidants such as H ₂ O ₂ and O ₃ are added at the same time, the effect will be better. However, since the traditional suspension-type photocatalytic oxidation directly puts TiO ₂ powder in wastewater and irradiates it with ultraviolet light, the separation of TiO ₂ powder and water after the reaction is time-consuming and laborious, so it cannot be popularized and applied. The traditional photocatalytic oxidation of fixed film adopts methods such as sol-gel or vapor deposition to form _TiO2 film on glass fiber (cloth), glass ball and other carriers in advance. The film forming method is complicated, the cost is high, and the thickness of the film Very limited, the efficiency of photocatalytic oxidation reaction is low, it is difficult to adapt to the requirements of practical engineering, at the same time, the cleaning or replacement of photocatalyst film after "poisoning" is complicated, which also limits the transformation of photocatalytic oxidation technology to practical technology. Therefore, photocatalytic oxidation technology has not been applied to practical water treatment projects so far.

Contents of invention

The object of the present invention is to solve the above problems, and design a new fixed-film photocatalytic oxidation water treatment system that is suitable for the needs of actual water treatment projects and can efficiently remove various organic substances in water.

The invention adopts a combination device of chemical oxidation, photooxidation and photocatalytic oxidation to completely remove various organic substances in water. The device used to realize the object of the present invention is composed of a water tank, a water inlet pump, a chemical oxidation reactor, a photocatalytic oxidation reactor, a flow meter and the pipes and valves connected together. The chemical oxidation reactor is fed with water from the upper part and discharged from the bottom. The photocatalytic oxidation reactor is an instant film-forming type, with water inflow from the bottom and water out from the top. There is a speed-regulating stirrer on the top of the water tank. A water inlet pipe and a water inlet control valve are successively arranged on the upper part of the water tank, and a medicine adding control valve and a medicine feeding port are also successively arranged on the water inlet pipe. The lower part of the water tank is connected with the water inlet pump through the water pump water inlet valve. The outlet of the water inlet pump is connected to the chemical oxidation reactor and the photocatalytic oxidation reactor respectively through a tee, two valves and two pipes, which are divided into upper and lower routes. The lower pipeline is first connected to the one-way valve at the water outlet at the bottom of the chemical oxidation reactor, and then connected to the water inlet at the bottom of the photocatalytic oxidation reactor and the vent valve installed at the bottom of the photocatalytic oxidation reactor through a tee, so that The photocatalyst is recovered through the vent valve. The water outlet on the top of the photocatalytic oxidation reactor is divided into two branches through a tee, and one branch is connected to the flow meter through the water outlet control valve, so that the qualified water after removing various organic substances is output from the flow meter to become clean water or The water can be discharged; the other branch is returned to the water tank through the return pipe to form a circulation. The upper pipeline of the water inlet pump is divided into two ways through a three-way connection, one way is connected to the water inlet valve on the top of the chemical oxidation reactor, and the other way is connected to the two return water pipes on the top return water pipeline of the photocatalytic oxidation reactor through a three-way connection. valve connection.

The photocatalytic oxidation reactor is an instant film-forming type, consisting of a spherical upper head with a flange, a conical lower head, a cylindrical shell, a partition with holes, a filter element, and an ultraviolet germicidal lamp with a quartz sleeve. Composition, it can instantly form a film on demand, undergo a photocatalytic oxidation reaction, and immediately backwash the photocatalyst film. A partition with holes divides the photocatalytic oxidation reactor into two parts, the upper part is a clean water chamber, and the lower part is a photocatalytic oxidation reaction chamber. The filter element is firmly welded into a cylindrical shape through a circular top plate, a stainless steel column, and a circular bottom plate, or it is firmly connected into a hexahedron shape through a hollow hexagonal top plate, a hexagonal bottom plate, and a stainless steel column through a nut. Tightly wrapped stainless steel mesh. The outer net of the filter element can be coated or removed with a photocatalyst film in real time to meet the process requirements for removing organic matter in water. The top fixing plate integrated with the filter element and the partition plate with holes are fixedly connected with filter element nuts and filter element bolts. The spherical upper head with flange, the perforated partition of the inherent filter element, and the cylindrical shell are integrated into one body by bolts and nuts. In the photocatalytic oxidation reactor of the present invention, the ultraviolet sterilizing lamp is connected to the power supply through the upper cover head, and the quartz sleeve and the upper cover head are sealed as a whole through a silk screen cap. Germicidal UV lamps with quartz sleeves are placed inside the filter element, or outside the filter element. In order to increase the light intensity, ultraviolet germicidal lamps may be installed inside and outside the filter element at the same time.

When working, first add photocatalyst powder into the water tank filled with water in advance, start the speed-regulating mixer, and make slurry. Then start the water inlet pump, and the photocatalyst slurry starts to circulate between the water tank and the photocatalytic oxidation reactor. After 20 minutes of circulation, the slurry will become clear, and a photocatalyst filter membrane has been formed on the surface of the filter element at this time. Then start to inject wastewater into the water tank, light up the ultraviolet germicidal lamp, open and adjust the outlet valve of the photocatalytic oxidation reactor, and control the outlet water flow according to the requirements of the wastewater quality and effluent water quality, that is, control the residence time of the wastewater in the photocatalytic oxidation reactor, Excess waste water is returned to the tank. When the wastewater flows through the photocatalyst filter membrane, under the irradiation of ultraviolet rays, the photocatalyst is excited and generates hydroxyl radicals (·OH) with strong oxidizing ability, which can directly oxidize and degrade the organic pollutants in the water into CO ₂ , Simple inorganic substances such as H ₂ O, or the oxidation of refractory organic pollutants into biodegradable organic substances, improve the biodegradability of wastewater.

In order to improve the rate and efficiency of the photocatalytic oxidation reaction, chemical oxidants can also be added to the water tank or chemical oxidation reactor. The oxidant used in the present invention can be ozone, hydrogen peroxide or pure oxygen, or air. Liquid or solid oxidant can be added into the water tank for reaction through the feed port on the water inlet pipe of the water to be treated at the upper part of the water tank, and gas oxidant can be added through the feed port at the bottom of the chemical oxidation reactor.

The photocatalyst in the present invention can be one or a combination of powders of TiO ₂ , WO ₃ , ZrO ₂ , V ₂ O ₅ , MoO ₃ and ZnO ₂ .

The present invention has following characteristics and advantages:

1. Owing to adding O _or (and) H _{2 O} oxidizers and _TiO photocatalysts such as photocatalysts such as adding O in the water tank of forming the present invention, chemical oxidation reactor, instant film-forming type photocatalytic oxidation reactor, make the present invention realize Combination of chemical oxidation, photooxidation and photocatalytic oxidation. The photocatalyst film of the present invention does not need to be prefabricated, but is formed immediately and backwashed immediately. The thickness, pore size and formulation of the photocatalyst film can be adjusted at any time. Light intensity can also be adjusted as desired. The pore size of the formed photocatalyst membrane is equivalent to the fine filtration membrane, so it has a fine filtration effect while completing the photocatalytic reaction, and can simultaneously remove water turbidity, SS, colloid, suspended matter and floating matter, and the turbidity of filtered water It can reach zero Ntu, and the water quality is clear and transparent. Therefore, the invention not only solves the problem of photocatalyst immobilization and the separation of photocatalyst and water after the reaction, but also has good effect of photocatalytic oxidation reaction.

2. The filter element in the instant film-forming photocatalytic oxidation reactor of the present invention can be assembled in advance, and the photocatalyst film can be formed on the filter element immediately, and the ultraviolet germicidal lamp set can be easily taken out and replaced, so the present invention Reasonable structure and convenient maintenance.

3. Since the present invention can conveniently backwash the photocatalyst film by using the water inlet pump, the photocatalyst under backwashing can also be used again. Therefore, the invention not only solves the problem of separating the photocatalyst and water after the reaction, but also can recover the photocatalyst with low operation cost.

4. The invention has a wide range of uses. It can be used alone for the treatment of various water and wastewater, and can also be used as pretreatment or terminal treatment of conventional water treatment processes. The effluent can be directly discharged or reused, eliminating the need for sedimentation, air flotation or other Solid-liquid separation means and terminal disinfection measures.

Description of drawings

Fig. 1 is a schematic diagram of the system of the present invention.

Fig. 2 is a schematic structural view of the photocatalytic oxidation reactor of the present invention.

Fig. 3 is A-A schematic diagram of the photocatalytic oxidation reactor.

Fig. 4 is a schematic structural diagram of a filter element of a photocatalytic oxidation reactor.

Fig. 5 is a B-B schematic diagram of the filter element of the photocatalytic oxidation reactor.

Detailed ways

See Figure 1. The present invention is formed by connecting a water tank 1, a water inlet pump 6, a photocatalytic oxidation reactor 12, a chemical oxidation reactor 20 and a flow meter 15 through pipelines. A speed-regulating mixer 2 is installed on the top of the water tank 1, and the stirring paddle of the speed-regulating mixer 2 is placed in the water tank 1. The upper part of the water tank 1 is provided with a water inlet pipe and a water inlet control valve 4 in sequence. The water inlet pipe is also sequentially equipped with a dosing control valve 3 and a dosing port, so that liquid or solid oxidant can be added in the water tank 1 as required. The lower part of the water tank 1 is connected with the water inlet pump 6 through the water pump water inlet valve 5 . The outlet of the water inlet pump 6 is connected to the chemical oxidation reactor 20 and the photocatalytic oxidation reactor 12 respectively through a three-way, two valves 7, 8 and two pipelines in an upper and lower way. The chemical oxidation reactor 20 is fed with water from the top and discharged from the bottom. The photocatalytic oxidation reactor 12 has water inflow from the bottom and water outflow from the top, and an observation window 13 is provided on the front. The lower pipeline of the water inlet pump 6 is first connected with the one-way valve 10 of the water outlet at the bottom of the chemical oxidation reactor 20, and then through a three-way connection with the water inlet at the bottom of the photocatalytic oxidation reactor 12 and the bottom of the photocatalytic oxidation reactor 12 The vent valve 11 is connected so that the photocatalyst is recovered through the vent valve 11. The water outlet at the top of the photocatalytic oxidation reactor 12 is divided into two branches through a tee, and one branch is connected to the flow meter 15 through the water outlet control valve 14, so that the qualified water after removing various organic substances is output from the flow meter 15 become clean water or dischargeable water; the other branch flows back into the water tank 1 through the return pipe and the return water control valve 16, 23 to form a cycle. The upper pipeline of the water inlet pump 6 is divided into two ways through a tee, one way is connected with the water inlet valve 21 at the top of the chemical oxidation reactor 20, and the other way is connected with the backflow water at the top of the photocatalytic oxidation reactor 12 through the valve 22 and a tee. The return water control valves 16, 23 on the pipeline and the return water pipeline connected with the water tank 1 are formed.

The chemical oxidation reactor 20 is composed of a shell 19 , upper and lower heads and a built-in polyhedral filler 18 . One side of the lower head of the chemical oxidation reactor 20 is equipped with a gas oxidant such as an ozone inlet with a one-way valve 9 . The added gas oxidant passes through the perforated plate 17 at the lower part of the chemical oxidation reactor 20 and contacts and mixes with the wastewater sprayed from the upper part in the polyhedral filler 18 to complete the chemical oxidation reaction.

Please refer to Figure 2 and Figure 3. The photocatalytic oxidation reactor 12 of the present invention is instant film-forming type, by the ultraviolet sterilizing of spherical upper end cap 24, perforated partition plate 25, bolt 26, nut 27, cylindrical shell 28, quartz sleeve 30 protection Lamp 29, filter element 31, conical lower sealing head 32, water distribution plate 33, silk screen cap 36 form, and its front is provided with observation window 13. The partition plate 25 with holes divides the photocatalytic oxidation reactor 12 into two parts, the upper part is a clean water chamber, and the lower part is a photocatalytic oxidation reaction chamber. The four filter elements 31 placed in the housing 28 are all integrated with the perforated partition plate 25 through the filter element nut 34 and the filter element bolt 35, and then the upper head 24 and the inherent filter element are fixed by bolts 26 and nuts 27. The perforated dividing plate 25 of 31, housing 28 are solid as a whole. An ultraviolet germicidal lamp 29 with a quartz sleeve 30 is inserted into the filter element 31 through the upper head 24 . The quartz casing 30 and the upper sealing head 24 are sealed as a whole through a silk screen cap 36 . The lower end of the conical lower head 32 has a water distribution plate 33 . See Figure 4 and Figure 5. Each filter element 31 is composed of a top fixing plate 37 , a top plate 38 , a stainless steel wire mesh 39 , a column 40 and a bottom plate 41 firmly connected. The top plate 38 is circular, and the diameter of its outer edge is equal to the diameter of the circular bottom plate 41 . Twelve columns 40 are firmly welded to the outer edges of the top plate 38 and the bottom plate 41 to form a skeleton, and then the stainless steel mesh 39 is tightly wrapped outside the skeleton to make the filter element 31 appear in a cylindrical shape. The top plate 38 of the filter element 31 is welded together with the top fixing plate 37 , and then the top fixing plate 37 on the filter element 31 and the porous plate 25 are fixed as a whole through the filter element nut 34 and the filter element bolt 35 . The inside of the filter element 31 is provided with an ultraviolet germicidal lamp 29 with a quartz sleeve 30 . On the stainless steel wire mesh 39, the photocatalyst filter material can be immediately coated or removed as required, so as to meet the process requirements for removing organic matter and turbidity, SS, colloid, suspended matter, floating matter, bacteria and viruses in water.

During work, first add commercially available TiO ₂ powder into the water tank 1 filled with water in advance, and start the speed-regulating mixer 2 to make a slurry. Then open the valve 5, start the water inlet pump 6, then open the valve 7, the return water control valve 16, 23, the photocatalyst slurry enters the photocatalytic oxidation reactor 12 from the bottom, and enters the inside of the filter element 31 through the gap of the stainless steel mesh 39 outside the filter element It flows into the clean water chamber, then flows out from the upper part of the photocatalytic oxidation reactor 12, and starts to circulate between the water tank 1 and the photocatalytic oxidation reactor 12. After 20 minutes of circulation, the photocatalyst slurry becomes clear, and a photocatalyst filter membrane has been formed on the surface of the filter element 31 at this time. Then inject waste water in the water tank 1, then light the ultraviolet sterilizing lamp 29, open and adjust the water outlet control valve 14, control the water outlet flow meter 15 to meet the water outlet flow rate of the process requirements, and determine the waste water in the photocatalytic oxidation reactor 12 according to the water quality of the waste water. During the residence time, the excess waste water is returned to the water tank 1. When the wastewater flows through the photocatalyst filter membrane, under the irradiation of ultraviolet rays, the photocatalyst is excited and generates hydroxyl radicals (·OH) with strong oxidizing ability, which can directly oxidize and degrade the organic pollutants in the water into CO ₂ , Simple inorganic substances such as H ₂ O. While the photocatalytic oxidation reaction is going on, the photocatalyst membrane is also playing a filtering role.

If it is necessary to add a liquid oxidant such as hydrogen peroxide, the oxidant can be added to the waste water through the dosing port on the waste water inlet pipe on the top of the water tank 1 and the valve 3, and the chemical oxidation reaction can be completed in the water tank 1.

If it is necessary to add a gas oxidant such as ozone, the photocatalytic oxidation reactor 12 can start to work, after controlling the outlet water flow of the flow meter 15, open the water inlet valve 21, then slowly open the valve 8, and slowly close the valve 7 at the same time , the waste water flows in from the upper part of the chemical oxidation reactor 20, flows out from the lower part and then enters the photocatalytic oxidation reactor 12. Open the ozone generator power supply, the ozone enters the chemical oxidation reactor 20 through the one-way valve 9, and the waste water sprayed down by the porous plate 17 provided with the upper part of the chemical oxidation reactor 20 is upwardly contacted in the polyhedral filler 18, mixed and Complete the chemical oxidation reaction. Ozone that has not reacted completely in the chemical oxidation reactor 20 undergoes a photooxidation reaction in the photocatalytic oxidation reactor 12 .

After a certain period of chemical oxidation, photocatalytic oxidation, photooxidation reaction and filtration, the filter residue layer on the surface of the photocatalyst membrane will gradually become thicker, and the water head loss between the reaction chamber of the photocatalytic oxidation reactor 12 and the clean water chamber will continue to increase. When the water head loss reaches 0.1Mpa or by adjusting the outlet water control valve 14 and the backflow water control valve 16, the required outlet water flow rate can not be obtained, the reaction can be stopped and flushing can be carried out. First close the water outlet control valve 14, the return water control valve 23, then close the valve 8, the water inlet valve 21, and close the water inlet pump 6. Then open the vent valve 11 of the photocatalytic oxidation reactor 12, and more than 90% of the photocatalyst filter membrane will fall off and flow out with water for recovery. Turn on the water inlet pump 6 again, open the valve 8, the valve 22, the backflow water control valve 16, and backwash the photocatalytic oxidant filter membrane on the filter element 31 from top to bottom, and the photocatalyst washed down can be recycled. When the filter element is rinsed clean, a new film-forming and reaction process can begin.

The invention can be used alone or in series with other water treatment units. If it is applied to wastewater treatment, the present invention can be used as a terminal oxidation unit and placed behind the biochemical reactor; it can also be placed in front of the biochemical reactor to improve the biodegradability of wastewater through photocatalytic oxidation. The invention can also be applied to the treatment of heavy metal wastewater and the recovery of heavy metals.

Claims (2)

1, a kind of instant film forming photochemical catalytic oxidation water treatment system, comprise water tank (1), intake pump (6), chemical oxidation reaction device (20), photocatalysis oxidation reaction device (12) and under meter (15), it is characterized in that: be provided with speed governing stirrer (2) in the water tank (1), water tank (1) top is provided with water inlet pipe and water inlet control valve (4) successively, and dosing control valve (3) and dosing mouth are housed on the water inlet pipe successively; Water tank (1) bottom is connected with intake pump (6) by pump inlet valve (5); The outlet of intake pump (6) divides upper and lower two-way to be connected with chemical oxidation reaction device (20), photocatalysis oxidation reaction device (12) respectively by a threeway, two valves (7), (8) and two pipelines; The pipeline on following road is connected with the check valve (10) of chemical oxidation reaction device (20) bottom water outlet earlier, and then is connected with the bottom water-in and the blow-off valve (11) of photocatalysis oxidation reaction device (12) respectively by a threeway; The water outlet at photocatalysis oxidation reaction device (12) top is by two branch roads of one three reduction of fractions to a common denominator, branch road is connected with under meter (15) by outlet water control valve (14), and another branch road is back to by return line and recirculation water control valve (16), (23) that formation circulates in the water tank (1); The pipeline of setting out on a journey of intake pump (6) is by one three reduction of fractions to a common denominator two-way, one the tunnel is connected with chemical oxidation reaction device (20) top water intaking valve (21), another road is by valve (22) and a threeway, be connected respectively with photocatalysis oxidation reaction device (12) top recirculation water pipeline, and with recirculation water control valve (23), water tank (1).

2. a kind of instant film forming photochemical catalytic oxidation water treatment system according to claim 1 is characterized in that: described photocatalysis oxidation reaction device (12) is made up of spherical upper cover (24), foraminous dividing plate (25), bolt (26), nut (27), cylindrical housings (28), quartz socket tube (30), ultraviolet germicidal lamp (29), filter element (31), taper lower cover (32), water distribution board (33), a silk mouthful screen cap (36); Place the filter element (31) in the housing (28) all to be solidified as a whole by filter element nut (34), filter element bolt (35), use bolt (26) and nut (27) that upper cover (24), foraminous dividing plate (25), housing (28) are solidified as a whole again with foraminous dividing plate (25); The ultraviolet germicidal lamp (29) that has quartz socket tube (30) passes upper cover (24) and inserts in the filter element (31); Quartz socket tube (30) is sealed into one with upper cover (24) by a silk mouthful screen cap (36); The intrinsic water distribution board in lower end (33) of conical lower cover (32); Filter element (31) firmly connects into cylindrical or hexahedral shape by top retaining plate (37), top board (38), post (40) and base plate (41), and the outside is tightly wrapped up Stainless Steel Cloth (39) and constituted; The ultraviolet germicidal lamp (29) of band quartz socket tube (30) places filter element (31) inside, perhaps places filter element (31) outside, perhaps is provided with simultaneously in filter element (31) inside and filter element (31) outside.

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