JP2000153268A - Treatment of liquid and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for treating liquid, which enables to dehydrate sludge in a high dehydration efficiency without using chemicals, to sterilize without using the chemicals and to treat without using a large power. SOLUTION: The liquid treating method is a method for converging laser 2 in a liquid to be treated to cause break down (dielectric break down) in the liquid 4. Plasma, radical, UV light and impulse are generated by the break down and the treatment is performed by the plasma, radical, UV light and impulse. The laser 2 is preferably scanned. As the laser 2, any one of the followings; pulse laser, Q-switching pulse laser, ultraviolet laser or laser exited by sunlight is used. The liquid to be treated is a solution containing bacteria or a solution containing sludge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for efficiently performing a large amount of sludge dehydration treatment, sterilization treatment, crushing of scales and solids, and prevention of biofouling by using a laser. , Liquid processing technology.

[0002]

2. Description of the Related Art Conventionally, in a sludge dewatering treatment, a polymer flocculant is added to excess sludge from an activated sludge method such as sewage, and the sludge is dewatered by a centrifugal separator or the like. It is said that it is necessary to make the addition ratio of the sludge and the polymer flocculant proper in order to efficiently perform the dehydration treatment. For example, in Japanese Patent Application Laid-Open No. 5-168977, in order to prevent floc sludge from being formed inside the centrifugal dewatering machine and to prevent the chemical injection rate from increasing, a flow rate ratio calculator is used and a viscometer is used. Although the centrifugal dehydrator is controlled, a centrifugal separator disclosed in JP-A-60-206458 or the like is used.

In a power plant or a factory using a large amount of freshwater or seawater, aquatic organisms adhere to an intake pipe and other water pipes to proliferate and narrow the flow passage area. For example, in nuclear power plants or thermal power plants that use large amounts of seawater as cooling water, aquatic organisms attach to equipment, pipes, and cooling water pipes, which grow and reproduce, reducing the amount of water withdrawal and heat. It causes various obstacles such as reduced efficiency and damage to exchangers and pumps. Therefore, it is necessary to prevent the adhesion, growth and reproduction of various aquatic organisms having the above-mentioned adhesive properties. Conventional methods for preventing aquatic organisms from adhering include a chemical treatment method, a physical treatment method, and a mechanical treatment method. First, as a chemical treatment method,
There are a chemical injection method using hydrogen peroxide and hypochlorous acid, an antifouling coating, an electrolytic method, a copper ion method, and the like. However, as a problem common to these methods, the toxicity of the chemical substance used or the generated chemical substance is pointed out, and environmental pollution due to this toxicity is regarded as a problem.

[0004] Physical treatment methods include a hot water treatment method, a fresh water treatment method, a hot air drying treatment method, an electric shock method, an ultrasonic method, and an ultraviolet irradiation method. However, when implementing the hot water treatment method, fresh water treatment method and hot air drying treatment method, the cooling water system must be temporarily stopped, but temporarily stopping the cooling water system has a major problem in power plants and the like. . In addition, in the electric shock method, about 800 V / c
An electric field strength of about m is required, and power consumption by continuous processing is enormous. Ultrasonic methods can damage the water tube walls. Mechanical treatment methods include the method of preventing larvae from entering using a microstrainer, the method of removing attached shellfish using an underwater robot, the method of removing attached larvae using a sponge ball or a water jet, and the work using tools and the like. There are laws.

[0005] For the sterilization treatment of water, the aforementioned ultraviolet irradiation method is often used. Ultraviolet light is known as a disinfectant for water. In the past, it was common to provide a bank of a series of UV bulbs and to flow the water to be treated over the surface of the bulb. This method has a number of disadvantages. First, the intensity of ultraviolet light varies depending on the distance from the surface of the bulb. Therefore, the valves must be placed very close together or a special valve array must be used to provide sufficient intensity of UV light to all of the water passing through the valves. Even with such an approach, the water flow through the bulb had to be relatively slow to provide adequate UV light to the water. Also, placing the valves in close proximity resulted in significant head loss. Second, the bulb tends to be coated or clouded, which reduces the intensity of the UV light. One solution to this problem is to increase the intensity of the UV light beyond what is initially required, so that even after the bulb has been coated, a suitable intensity of UV light is obtained. Met.
Third, the bacteria attached to the suspended particles,
When blocked from the light source by these particles, there is a possibility that they will not be exposed to ultraviolet rays.

[0006] In addition to the bulbs or lamps currently used for sterilization, there are various sources of ultraviolet light. As one of the light sources that can emit light in the gratitude area,
There are lasers with appropriately selected laser excitation gases. The use of lasers to generate gratitude light for the sterilization of wastewater has not heretofore been proposed. The laser is
It has been found that it has a number of operational advantages, such as flow rate, or properties of water or other liquids such as turbidity, organic matter content. The laser can generate high intensity ultraviolet light, so it can increase the flow rate of water, reduce head loss, adapt to high turbidity water, and prevent bacteria from being exposed to ultraviolet light Reduce sex.

As one of the water treatment means, a treatment method using underwater pulse discharge is known in addition to the above-described method. In this treatment method, electrodes are installed in water,
By performing high-power pulse discharge in a liquid, water treatment is performed by accompanying plasma, UV light, radicals, and shock waves. These plasma and
It is used for water treatment such as sterilization, sludge, and solid matter crushing using UV light, radicals, and shock waves. In sterilization and sludge treatment,
Processing using plasma, UV light, radicals, and shock waves is performed. When these phenomena are used in combination, effective processing becomes possible. Microorganisms that are not easily sterilized or cell wall damaged by UV alone can effectively treat plasma, radicals, and shock waves by superimposing the effects.
In the case of crushing a solid object, a treatment using a shock wave is performed. By using a container in which the shock wave generated by the pair of electrodes can be focused again at another place, the solid object is set at the refocusing point, and the solid object is crushed by the focused shock wave. . When the shock wave is focused, the strength of the shock wave increases, that is, the pressure fluctuation increases, and when the solid object is irradiated, the pressure fluctuation increases and the shock wave is broken.

In Japanese Patent Application Laid-Open No. 5-168977, as described above, in the sludge dewatering technology, a centrifugal dewatering machine is used to prevent the chemical injection rate from increasing.
Using a flow rate ratio calculator and controlling using a viscometer, in order to further improve the dewatering rate of the sludge dewatering technology, JP-A-8-57475 discloses that sludge water is irradiated with a laser. He proposes that if the cell wall of sludge is destroyed by a laser, the sludge dewatering efficiency can be increased thereby. Regarding the sterilization of water, the invention of Japanese Patent Application Laid-Open No. 61-263690 shows a method of using a laser efficiently and effectively in sterilizing water. The killing ability of lasers that emit in the ultraviolet spectrum consists primarily in killing bacteria by direct contact, rather than by secondary photochemical effects. These side effects may also have the effect of killing bacteria,
The sterilization process has only a negative effect. JP 61
Although the method and apparatus of the invention of -263690 is particularly suitable for the treatment of water, it can also be used for the sterilization of common liquids, including water-based or non-water-based liquids. Thus, attempts are being made to utilize lasers in connection with water treatment.

[0009]

In the above-mentioned dewatering of sludge, in the solid-liquid separation method using a chemical such as a flocculant, the separated liquid is discharged as it is, but the sludge containing solids is centrifuged. After passing through the separator, the dewatered cake still contains considerable moisture. In the technical field of the current dehydrator, the dehydrator main body and the flocculant are being developed, but the water content of the dewatered cake is insufficiently reduced, and further reduction is difficult with the current technology. This is because the cell liquid of the microorganisms present in the sludge occupies a large proportion as residual water, and is largely due to the difficulty of dehydration.

[0010] The problem of aquatic organisms adhering to a thermal power plant or the like is caused by the problem of large-sized equipment, necessity of complicated maintenance, improper processing as a method for treating narrow pipes, and a great deal of labor and time. Yes, and they are also struggling with the disposal of aquatic waste generated after removal. In the conventional laser processing technology, the laser irradiation intensity is low, and the place where the laser is irradiated is limited to a part of the pipeline flow. For example, JP-A-8-164188
In the method as shown in FIG. C-1 of the publication, light irradiation is performed in a state where the laser intensity has a distribution below the size of the eleven laser transmission windows. Therefore, there is a region that is not irradiated with light or a region that is weakly irradiated. When the flow rate is high, the irradiation time is short, so that the sterilizing effect is small. In order to solve this problem, it is necessary to perform laser irradiation by turning many times, but for that purpose, it is necessary to increase the size of the device, and to increase the reach of laser intensity, a large output laser is required, High cost is required. In a situation where a large number of microorganisms are present, the microorganisms are irradiated with laser light in a state where the microorganisms overlap each other. Therefore, although the microorganisms received first have a high bactericidal effect, the germicidal effect of the microorganisms located on the back as viewed from the incident side occurs because the irradiation intensity decreases. Further, in a building or the like, when time elapses, propagation and transport of microorganisms may be newly performed in a flow path after laser irradiation (a place where laser is not irradiated).

With respect to the sterilization method, a problem when using the conventional laser irradiation is that the sterilizing effect is small because the light intensity is low. In addition, since the effect is exhibited only in the portion where the light hits, the place is restricted. In order to exhibit a bactericidal effect, there is a restriction to use an ultraviolet laser. Furthermore, in the processing technology using underwater pulse discharge, this processing method has an effect only in the vicinity of the position where the electrodes are installed, and requires a large number of electrodes and a large output power supply for a large amount of processing, resulting in high cost. . In addition, there is a problem that the electrode material dissolves during discharge. Additional means such as separation and recovery of the eluted metal are further required. In addition, long-term use makes it impossible to maintain a normal discharge due to adhesion of contaminants on the electrode surface, etc., so that high cost is required for maintenance.

As described above, the points to be solved include the following. Sludge treatment: In the sludge dewatering treatment, conventionally, a large amount of chemicals such as a flocculant had to be used. In addition, the dewatering efficiency was poor, and it was difficult to make a low-moisture cake of sludge. Further, in the case of underwater pulse discharge, a large amount of electrodes and a large amount of electric power are required, and there are complicated steps such as limitation of the effect area and addition of a post-metal recovery treatment step due to dissolution of the electrode material. Sterilization treatment: Use limited to ultraviolet lasers.
In addition, the light intensity is low, and a very high cost is required to achieve a high output. Also, since it is a process where there is a flow,
Low irradiation dose / light intensity per unit flow rate and low processing effect.

Further, in the case of underwater pulse discharge, a large amount of electrodes and a large amount of electric power are required, and there are complicated steps such as limitation of an effective area and addition of a post-processing step of metal recovery by melting out electrode materials. Prevention of aquatic organism adhesion: Conventionally, the mechanical method has problems of large size of equipment, necessity of complicated maintenance, inadequacy as a treatment method in narrow pipes, and great labor and time, and also occurs after removal. They also struggle with the disposal of aquatic waste. Even with the laser method, the conventional method has problems in that the processing area is limited, the light intensity is low, and the processing effect is weak. Crushing of solids: Treatment mainly using shock waves, but conventionally, shock waves due to underwater discharge are used. In this method, an electrode for underwater discharge is required, and unstable operation occurs due to water contamination due to leaching of the electrode and contamination of the electrode surface, and maintenance is complicated. Thus, it is necessary to be able to solve these problems when applying a laser.

[0014]

Means for Solving the Problems The present inventor has studied means effective not only for water treatment but also for liquid treatment widely. Since laser treatment is commonly used, attention has been paid to laser treatment. However, the conventional laser processing has a disadvantage that the processing effect is small, and this means has not been practically used conventionally. However, the present inventor has studied a laser processing technique, and found that a larger processing effect can be obtained by causing a breakdown (dielectric breakdown) by the laser, thereby developing a laser processing technique having a larger processing effect. Things.

That is, the present invention has solved the above-mentioned problems by the following means. (1) A liquid processing method characterized in that a laser is focused on a liquid to be processed to cause breakdown (dielectric breakdown) in the liquid. (2) Plasma by breakdown (dielectric breakdown)
Generating radicals, UV light and shock waves,
The liquid treatment method according to the above (1), wherein the treatment is performed by radicals, UV light and shock waves. (3) The liquid processing method according to (1) or (2), wherein the laser is scanned (scanned). (4) The laser according to (1), wherein any one of a pulse laser, a Q switching pulse laser, an ultraviolet laser, and a laser excited by sunlight is used as the laser.
The liquid processing method according to any one of (1) to (3).

(5) The liquid according to any one of (1) to (3), wherein the liquid to be treated is a solution containing bacteria and the laser is used to kill the bacteria. The liquid treatment method as described in the above. (6) The liquid according to any one of (1) to (5), wherein the liquid to be treated is a solution containing sludge, and the sludge is decomposed by the laser to reduce the sludge volume. Liquid treatment method. (7) The liquid treatment method according to any one of (1) to (5), wherein an object in the liquid to be treated is crushed by the laser. (8) The liquid treatment method according to any one of the above (1) to (5), wherein the laser is used to suppress an organism from adhering to a container wall or a building wall in contact with the liquid. (9) A liquid processing apparatus comprising: a laser generation device; and a device for converging a laser from the laser generation device on the liquid to be processed with sufficient intensity to cause breakdown (dielectric breakdown) in the liquid to be processed. apparatus.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that, when a laser is used for liquid processing, laser-induced breakdown (dielectric breakdown) is caused in the liquid to be processed by the laser, and the effect is utilized. This is fundamentally different from the conventional laser utilization technology. That is, the present invention utilizes the action of laser-induced breakdown (dielectric breakdown), and does not merely irradiate the liquid with laser light. Only when a high-intensity laser beam is focused and a high energy density state is achieved,
Laser breakdown can be realized. When this laser breakdown occurs, physical and chemical phenomena different from the case of simply irradiating a laser occur in a liquid (solution), and it is possible to perform efficient liquid treatment using the phenomenon. It is a feature.

The laser breakdown will be described in detail below. When the laser beam is condensed and a very high electric field intensity is locally attained and exceeds about 10 ¹⁰ W / cm ² , the electrons in the atoms violently vibrate and desorb. At the same time, dissociation of molecules occurs, and plasma and radicals are formed. At this time, a high-pressure, high-density, high-temperature state is formed in the portion where the laser is focused, and a shock wave due to the high pressure, high density and high temperature is also formed. Further, with the formation of the above-described plasma, radicals, and shock waves, UV light (in addition, visible light and infrared light are naturally generated) also occurs. Such phenomena are explained by theories such as multiphoton absorption of molecules and high-frequency discharge mechanism of electrons. In some cases, cavitation and X-rays may occur. Although the laser beam is condensed even in the conventional treatment by laser irradiation (Japanese Patent Application Laid-Open No. Hei 8-57475), since the laser output is only 50 W, laser breakdown does not occur.

The basic actions of plasma, radicals, UV light and shock waves in laser breakdown will be described below. In the area of laser breakdown, high-density light energy is concentrated, resulting in high-temperature, high-density, high-pressure conditions.
Plasma, UV light, radicals, and shock waves are formed. Hereinafter, each operation will be described. Plasma: Ions (positive / negative ions) and electrons are present in the plasma, which excites atoms and molecules at a high level, breaks bonds and atoms in solid and organic substances, dissociates liquid molecules, and emits light. Do. Therefore, a high chemical reaction and a secondary heating state are generated. In particular, the presence of ions significantly improves the effect of the chemical reaction. As ions and radicals in plasma, for example, considering water, H, O
There are H ions and radicals. When a stronger plasma is generated, H, H ₂ , O, O ₂ , OH
There are species of ions and radicals. These have a high effect on sterilization and cell membrane dissolution.

Radicals: Generated by plasma and photoexcitation. It is mainly formed by dissociation of molecules and activation by excitation of atoms and molecules. For example, H ₂ O (water molecule)
Is decomposed into H and OH, and OH produces a particularly high bactericidal action and a dissolving action for inorganic and organic substances. UV light: By photoexcitation of atoms and molecules and plasma excitation
appear. UV light has a germicidal effect. It also has an effect on the relaxation and destruction of interatomic bonds in solids and organic substances. Shock wave: The pressure, density,
Generates rapid changes in temperature. This rapid change has effects on sterilization, destruction of organic substances such as cell membranes, and destruction of solids. This plasma, radical, UV light, and shock wave
A narrow area where the laser is focused, for example, 10 × 10μ
is condensed in the area of m ^2, when the breakdown occurs, not only occur only in that region, its occurrence happened to its peripheral region, up to 100 times more area at a volume ratio, the liquid treatment effect Can be exerted.

The operation and effect of the liquid treatment using the laser breakdown according to the present invention will be described in more detail. 1) When liquid processing is performed using laser breakdown, liquid can be processed in a non-contact manner. That is, a solid object such as an electrode in a liquid is not required as in underwater pulse discharge. In this step, no contaminants such as chemicals are required. In other words, for example, it is possible to eliminate or simplify processes such as maintenance by electrode corrosion and melting required for conventional underwater discharge and mechanical treatment, post-treatment such as metal recovery and chemical solution separation, and the cost and efficiency are high. give. In the present invention, since only the incidence of the laser beam is performed in the liquid, all the control can be performed in a place separated from the liquid to be treated. Therefore, control can be performed regardless of the liquid, so that controllability is good. In the case where an electrode or a chemical is required, the control system is greatly influenced by the surface state of the electrode in the liquid, the mixed state of the chemical, and the reaction state, and thus the controllability is poor as compared with the present invention.

2) Laser, breakdown, plasma, radicals, UV light, and shock waves are generated. Liquid processing is performed using these. If these effects are used, not only the narrow region where the laser is focused, but also the periphery of the laser focused region, the effective affected region can be expanded. FIG. 8 shows a principle diagram of laser breakdown. The laser 2 is condensed to form a condensed spot A on the condensing portion 6, where a laser breakdown occurs due to the high energy, but a plasma generation region B and a radical generation region C around the periphery and a shock wave region outside the laser generation region B. D is formed, and a shock wave 29 exits from the surroundings. 3, 4) By scanning the laser, the location where laser breakdown occurs can be changed, so that a wide range of liquids can be affected with respect to the liquid to be processed. That is, large area and large capacity processing can be performed efficiently. In recent years, laser pulse oscillation is possible up to about 10 KHz to 1 MHz, and by using this technique, laser breakdown can be performed at 10 KHz to 1 MHz. That is, 1
Laser breaking can occur 10,000 to 1,000,000 times per second, and by gradually changing the location by scanning, it is possible to exert a processing effect on the entire area of the liquid.

At this time, it is particularly efficient to use a Q switching giant pulse laser. In the Q switching giant pulse laser, laser oscillation with a high peak value is possible, so that a higher energy density can be realized. For example, in the case of a ruby laser, the pulse oscillation of a normal oscillation pulse laser is
/ Cm ² level output, but a Q switching giant pulse laser can achieve a peak output of about 40 MW / cm ² with a pulse width of 25 ns. In addition, titanium sapphire laser, long and short pulse laser, 1
00fs pulse, 150μJ energy, wavelength 790n
With a m-titanium sapphire laser, an energy density of 1 TW / cm ² or more in the focusing region can be obtained. Such a high power density is difficult with a continuous oscillation system. Normally, pulse output can obtain a higher peak output than continuous oscillation. Approximately several tens of times higher peak output is obtained in normal pulse oscillation, and higher peak output is obtained in Q switching. When such a high peak output is obtained, a strong plasma / radical / UV light / shock wave is obtained when laser breakdown occurs, so that a strong processing effect can be obtained.

5) As a laser, an ultraviolet laser can be used. As an ultraviolet laser, for example,
Excimer laser, ruby laser, nitrogen laser, N
d: A harmonic (fourth harmonic) laser of YAG or the like can be used. As described above, when the laser itself that causes laser breakdown is ultraviolet light, the energy of the wavelength is relatively high, and the laser breakdown easily occurs. Further, the liquid treatment by the ultraviolet effect can be performed more effectively. For example, for sterilization and sludge treatment, if an ultraviolet laser is used as a laser, it itself exerts an ultraviolet sterilization action and a cell damage action,
It is more efficient.

6) As the laser, a laser excited by sunlight can be used. As a result, the energy efficiency is dramatically improved, and a laser liquid processing system with low energy supply can be realized. In a laser oscillator, there are usually many lamp excitations and discharges. In order to reduce the power consumption, in the present invention, it is preferable to use a laser oscillator excited by sunlight. A solid-state laser such as an Nd: YAG laser or a gas laser such as CO ₂ can realize such a solar-pumped laser oscillator. In a system that performs continuous processing, a combined use method with lamp excitation is used. Further, if the processing can be performed on a sunny day, only the solar light excitation system may be used.

7) When a liquid containing bacteria is treated as the liquid to be treated, a strong sterilizing effect can be obtained. Compared to UV light irradiation or laser light irradiation, not only can treatment be performed by giving high-density laser energy, but also plasma, radical, and UV generated accompanying
This is a process that uses both light and shock waves. In addition, there is no adverse effect due to solids such as electrodes and their dissolution in the liquid. In addition, since no chemical is used in this step, the post-processing step is simplified, and there are great advantages in terms of cost and efficiency.

8) In treating a solution containing sludge, a problem of the conventional dehydration treatment is that the dehydration rate cannot be increased. It is believed that the main cause is that the cells of the attached microorganisms are not destroyed and the cell fluid cannot be dehydrated. In the present invention, since the cell has a strong cell destruction effect, the sludge-containing liquid can be efficiently treated. Laser breakdown not only provides high-density laser energy to achieve cell destruction, but also generates plasma, radicals, UV light,
By using the shock wave, a powerful cell destruction effect can be exerted even around the laser focusing area. Also,
Since the processing area can be enlarged by scanning the laser, efficient mass processing can be performed. In the present invention,
By the method using the laser breakdown, the dewatering efficiency is 150 to 200% as compared with the ordinary mechanical processing method.
Or better results were obtained.

9) Performing a destruction treatment of a solid in a liquid by using a laser breakdown has the advantage that scattering of the destruction can be suppressed. Conventionally, a shock wave caused by electric pulse discharge by an electrode has been used for this destruction treatment. At this time, corrosion and breakage of the electrode and melting of the electrode material become a problem, which is a factor that complicates the post-treatment process. According to the laser breakdown as in the present invention, not only the shock wave generated by the laser breakdown but also the laser energy can be directly applied to the object to be destroyed, and more precise destruction becomes possible. Also, no electrode maintenance is required. Good controllability for non-contact operation. There are merits such as a simple post-processing step. In the present invention, as the solid material, specifically, a processed product (size: 10 × 10 cm) obtained by chipping a personal computer, a car, or the like, a concrete lump (size: several cm), and the like can be considered. By these crushing and disintegration, for example, gold is collected from an IC chip, or concrete and a reinforcing bar are separated, and a reinforcing bar is recovered. Further, a harmful substance (for example, summary or GaAs used for an IC chip or a circuit) can be separated and subjected to a recovery treatment so as not to diffuse to the outside.

10) Using laser breakdown,
A remarkable effect can be exhibited in the killing treatment of the aquatic organism-containing solution and the prevention of adhesion of shellfish and the like adhering to the shore wall. According to the laser breakdown, strong killing damage can be given to aquatic organisms, and thus particularly strong killing damage to juveniles can be given. In addition, physical damage can be given to prevent adhesion of grown shellfish and the like. In addition, since an arbitrary area can be irradiated by scanning, the effect can be uniformly exerted on all the fluid volumes to be processed. These can produce effects mainly by using shock waves due to laser breakdown.
Further, since no chemicals or electrodes are used, there is no risk of water pollution due to them.

[0030]

The present invention will be described in detail with reference to the following examples. However, the present invention is not limited to only these examples.

Embodiment 1 FIG. 1 shows an outline of Embodiment 1. In FIG. 1, a laser 2 emitted from a laser oscillator 1 is condensed by a condensing mirror 3 and forms a condensing portion 6 in a liquid 4 in a container 5 to cause a laser breakdown, causing plasma or the like to surround the laser. The generated active region 7 is formed. The laser used is a pulsed CO ₂ laser, an oscillation wavelength of 10.6 μm, and a beam diameter of 30.
mm, 1 kW to 10 kW output control, 10 to 1 kW
Those capable of pulse oscillation of z were used. The beam oscillated from the laser oscillator is guided into the solution in the container by the focusing mirror and focused. A solution for sterilization or sludge treatment is contained in the container. The laser focuses into this solution to reach a high energy density of the following magnitude, causing breakdown in a pulsed manner, thereby generating plasma, radicals, UV light, and shock waves. By these actions, liquid processing is performed.

The light condensing area is an area having a diameter of 50 μm, and the light intensity is 3.6 TW / cm ² or more. Due to the high energy density, the breakdown of the liquid occurs, and the above-described plasma, radical, UV light, and shock wave are generated. These reach a region wider than the focusing region, and the plasma is 100 to 1000 times in volume ratio and the radicals are 100 to 1000 times.
An area of 0 to 100000 times can be reached. Further, the UV light and the shock wave reach an area of 1,000,000 times or more. Due to the combined effect of such phenomena, the effective working area is expanded, and the action can be exerted on the entire container. If the operation is limited, the optical system can be moved to exert an effect on the entire liquid in the container.

As the laser used here, a CO laser, YAG (Nd: YAG) is used in place of the CO ₂ laser.
Etc.) Laser, Ar ion laser, glass laser,
Excimer laser, ruby laser, N ₂ laser, titanium sapphire laser, iodine laser, H ₂ O laser, HF laser, dye laser, semiconductor laser and the like can be similarly used. The following two cases are shown as the treated liquid. 1) In the case of sterilization of water: Yeast bacteria, actinomycetes, filamentous fungi,
Contains bacteria, protozoa, algae, etc. Such water can be subjected to the above-described laser breakdown to perform sterilization. 2) Sludge treatment: The aqueous solution contains sludge. Before the dehydration treatment, the cells of the microorganisms are destroyed by the above-described laser breakdown, so that the dehydration efficiency can be drastically increased. In the dewatering of sludge, the dewatering rate when using a dewatered cake using a normal mechanical dewatering machine is a weight ratio, 80 to 60% for clean water, and sewage for clean water Although it is 85 to 70%, when laser breakdown is performed on these, the sludge dewatering efficiency is improved by 150 to 200% as compared with the above case.

Example 2 As shown in FIG. 2, when an aqueous solution containing sludge or water that needs to be sterilized is flowing through a flow path, a laser breakdown is caused by a condensed laser and the sludge is generated. Perform treatment or sterilization treatment. In FIG. 2, a laser 2 emitted from a laser oscillator 1 changes an optical path by a reflection mirror 8, and a part goes to a condensing / scanning mirror 10 by a half mirror 9, enters a liquid flow 12 below, and is Causes laser breakdown, and the rest of laser 2
The scanning mirror 11 enters the lower liquid flow 12 and also causes laser breakdown there, so that the laser breakdown can occur at two locations. The laser is a Q-switch giant pulse laser with a beam diameter of 30 mm and an output of 25 n pulse width.
s, peak power 40 MW / cm ² , repetition frequency 10
Irradiation at 0 kHz.

As shown in FIG. 2, the emitted laser 2
Is split into two beams by the half mirror 9,
Liquid treatment is performed in two places. This is to increase the processing level by performing the repetitive processing. One beam reflected by the half mirror 9 is reflected by the condensing / scanning mirror 10, and condenses the beam. At this time,
By scanning the condensing / scanning mirror 10, the effect of breakdown can be exerted on the liquid flowing through the flow path without leakage. Further, the remaining beam is reflected by the condensing / scanning mirror 11, and the beam is condensed. By scanning the mirror, the effect of the breakdown can be exerted on the liquid flowing through the flow path without leakage. . Although this drawing is a cross section, since the scanning is actually performed on the cross section of the flow path, the processing can be performed as shown in the perspective view of FIG. In this figure, it is possible to perform the breakdown by changing the location and to apply the processing effect of the breakdown to all of the liquid flowing in the unit time. This is made possible by controlling the flow velocity, focal length, and scanning speed.

In order to further enhance the processing effect, an optical system for performing multiplex processing is provided. That is the second stage (downstream side) laser breakdown. Beam scanning and breakdown are performed as described above. The effect can be improved by using a higher output excimer laser as the laser. In order to keep costs low, a CO ₂ laser or a YAG laser can be used. The method of FIG. 4 can also be used. In this method, the passage area of the fluid is reduced by the flow path restricting mechanism 15. Immediately after the liquid has passed, laser breakdown is performed and beam scanning is performed. Since the liquid passes through the narrowed cross-sectional area, by performing the beam scanning for the breakdown in a narrow region, the effect of the breakdown can be given to the passing liquid without leakage.
Although the flow velocity of the liquid is increased by narrowing the flow path, it can be ignored compared to the scanning speed of the laser.

Embodiment 3 This embodiment is characterized in that a hybrid system laser using both solar excitation and lamp excitation is used as a laser oscillator. When the laser of this hybrid system is used for an example like Embodiments 1 and 2,
Since the power consumption can be significantly reduced, lower cost can be realized. Since the laser is used to excite a YAG laser, which is an Nd: YAG laser, with sunlight, FIG.
As shown in (1), the sunlight 16 is condensed by using the solar collector 17 and the reflection mirror 18 and introduced into the YAG rod 21 from the YAG laser resonator mirror 1 to perform optical excitation.
The excited metal ions Nd in the YAG rod (or slab) 21 emit light having a laser wavelength of 1.06 μm, and a first resonator mirror and a second resonator mirror (not shown) of the laser resonator 22. As a result, light is amplified by stimulated emission, and a laser beam is emitted from the second resonator mirror. The second resonator mirror is provided with a mechanism for Q-switch giant pulse laser oscillation.
Thus, the emitted laser beam is a Q-switched giant pulse laser. Also, if the laser output due to sunlight excitation is insufficient due to insufficient sunlight,
The required output can be achieved in conjunction with lamp excitation.

The laser emitted in this manner is condensed by the reflection mirror 8 and the condensing mirror 3, and the condensing portion is guided into the liquid 4 to be processed. At the condensing part in this liquid, breakdown occurs, and plasma, radicals, and U
V light and shock waves are generated to process the liquid. As the treatment, sterilization and sludge treatment can be performed. At this time,
It is also possible to provide a beam scanning or a moving mechanism of an optical system to exert a processing effect on the entire liquid.

Example 4 This is an example of prevention of biofouling. As shown in FIG. 6, in the vicinity of the water intake 23 of a power plant or a factory, the floating larvae of aquatic deposits are killed, and the aquatic organisms are prevented from adhering to the water intake channel. As aquatic organisms, oysters, mussels, wisteria, etc. can be considered. A Q switch giant pulse laser such as a CO ₂ laser or an Nd: YAG laser is used. The laser beam is condensed using a condensing mirror, a condensing / scanning mirror, or a condensing lens to cause a breakdown. A breakdown occurs just before the intake. At this time, by performing beam scanning, the processing area can be expanded and the effect can be improved.
In addition, by using a hybrid system laser of lamp excitation and sunlight excitation, the sunlight excitation method is performed on a sunny day, and when the output is insufficient due to sunlight excitation, the lamp excitation is used together to reduce the power consumption. can do.

Example 5 This is an example of crushing solids in water. As shown in FIG. 7, an object 28 to be crushed is placed on a sample stage 27 in a liquid (water), and is irradiated with a laser beam focused on the object to be crushed by a condenser lens 25. The object 28 is crushed. At this time, the movement mechanism 26 controls the movement of the position of the light collecting unit. The position is moved from the vicinity of the object to be crushed, and the condensing part is gradually moved to the center of the object to be crushed. In this method, a more effective crushing is performed by first performing a breakdown in the vicinity of the crushed object, generating a crack on the surface mainly by a shock wave, and moving a position where the breakdown occurs to the center of the crushed object. As the laser, the lasers described in Examples 1 to 4 can be used. In particular, it is effective and efficient to use a Q-switch giant pulse laser.

[0041]

According to the present invention, since the laser breakdown involves generation of plasma, radicals and shock waves, the following excellent effects can be obtained. When the sludge is dewatered, an excellent dewatering efficiency of 150 to 200% or more is obtained as compared with the conventional method. When performed for sterilization, in addition to having high sterilization efficiency, it can act on a wide range and give a high sterilization effect to liquid flowing through a wide flow path, and there is no need to use a large amount of chemicals at all. The biofouling prevention treatment also has a strong effect and acts on a wide range. Scanning can provide a biofouling prevention effect over a considerably wide range. It also has the effect of destructing solid objects, and can easily recover valuable resources from those containing harmful substances or valuable substances, and prevent harmful substances from being emitted to the outside world. Compared to underwater pulse discharge, the electric power used is significantly less, there is no need to use chemicals, and there is no problem such as the dissolution of the metal used for the electrodes.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which a laser is focused on a liquid to cause laser breakdown.

FIG. 2 is an explanatory diagram showing laser breakdown in a liquid that flows by condensing a laser at two or more locations.

FIG. 3 is a perspective view illustrating a state of movement of a laser condensing portion with respect to a liquid in a flow channel in FIG. 2;

FIG. 4 is an explanatory diagram of a state in which laser breakdown occurs when a flow path restrictor for a liquid is provided in the flow path.

FIG. 5 is an explanatory diagram of a laser irradiation state when a solar light pumped laser is used.

FIG. 6 is an explanatory diagram of a laser irradiation state when laser irradiation is performed on a water intake such as cooling water.

FIG. 7 is an explanatory diagram of a laser irradiation state when crushing solids in water.

FIG. 8 shows a principle diagram of laser breakdown.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser oscillator 2 laser 3 focusing mirror 4 liquid 5 container 6 focusing section 7 active area 8 reflecting mirror 9 half mirror 10 focusing / scanning mirror 11 focusing / scanning mirror 12 liquid flow 13 liquid level 14 scanning 15 flow path Aperture 16 Sunlight 17 Sunlight collector 18 Reflecting mirror 19 Excitation light incidence 20 Excitation lamp 21 Laser rod 22 Laser resonator 23 Water intake 24 Pulse laser 25 Condensing lens 26 Moving mechanism 27 Sample table 28 Crushed object 29 Shock wave A Focused spot B Plasma generation area C Radical generation area D Shock wave generation area

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Chiaki Igarashi 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside Ebara Research Institute, Inc. (72) Inventor Kazuo Yamauchi 4-2-2 Motofujisawa, Fujisawa-shi, Kanagawa No. 1 F-term in EBARA Research Institute, Ltd. (reference) 4D037 AA12 AB03 BA16 BA18 BB01 4D059 BK11 BK13 BK23 BK24 BK25 CA21 4D067 CD05 GA20

Claims (9)

[Claims] 1. A liquid processing method comprising: focusing a laser beam on a liquid to be processed; and causing breakdown (dielectric breakdown) in the liquid. 2. The liquid processing method according to claim 1, wherein plasma, radicals, UV light and shock waves are generated by breakdown (dielectric breakdown), and the processing is performed by the plasma, radicals, UV light and shock waves. . 3. The liquid processing method according to claim 1, wherein the laser is scanned (scanned). 4. A pulse laser as the laser,
The liquid processing method according to any one of claims 1 to 3, wherein one of a switching pulse laser, an ultraviolet laser, and a laser excited by sunlight is used. 5. The liquid treatment according to claim 1, wherein the liquid to be treated is a solution containing bacteria, and the laser is used to kill the bacteria. Method. 6. The method according to claim 1, wherein the liquid to be treated is a solution containing sludge, and the sludge is decomposed by the laser to reduce the volume of the sludge.
The liquid treatment method according to the above item. 7. The liquid processing method according to claim 1, wherein an object in the liquid to be processed is crushed by the laser. 8. The liquid treatment method according to claim 1, wherein the laser is used to suppress an organism from adhering to a container wall or a building wall in contact with the liquid. 9. A laser generator, and a device for converging a laser from the laser generator to the liquid to be processed with sufficient intensity to cause breakdown (dielectric breakdown) in the liquid to be processed. Liquid treatment equipment.