JP2002096097A - Method of removing heavy metal in sludge and sludge which is made pollution-free - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly remove the heavy metals in sludge. SOLUTION: Membranes are clogged by virtue of the nature of material known as sludge in a membrane type separation method and therefore a separating means which is the same electrophoresis but gathers and discharges the heavy metals to a cathode side by passing electricity in a horizontal direction when the sludge is put into water and particles fall is adopted. The effective utilization of the sludge is made possible, by which the amount of utilization is expanded and incineration disposal and burying disposal are averted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for removing heavy metals contained in sludge.

[0002]

2. Description of the Related Art The amount of sludge to be discarded is enormous, and it is necessary to use technology for removing heavy metals contained in sludge when using it in any way. The harm was so great that removal techniques were needed. Conventionally, there have been a method using a chemical treatment and a method using an ion-permeable membrane. Techniques using heavy metals include electroplating, cathodic protection, and the like. For the ion permeable membrane, refer to Japanese Patent Application No. Hei 11-335.
There were 95 technologies. For ion permeable membranes, there was a technology as a pre-treatment for waste disposal of plating effluent, and there was a technology to use a permeable membrane to improve water quality when using groundwater as agricultural water. In electroplating, it was a technique of depositing through electricity under the conditions of high concentration metal and high concentration electrolyte. In cathodic protection, rust (oxidation of metal) is suppressed by passing a trace amount of electricity through tap water for a long time to attach a trace amount of metal to the water and replenishing ions to prevent the release of ions from the pipe (metal). There was technology. Both electroplating and cathodic protection are techniques for attaching metals, but not techniques for removing metals.

[0003]

The separation of heavy metals in sludge by electrophoresis can be considered, but clogging of the membrane is a major problem in the ion permeable membrane system. Japanese Patent Application 11
In the technique of No. 33595, there is no description about the amount to be treated, and clogging of the permeable membrane is mentioned as a major problem.

[0004]

[Means to be Solved] In the membrane type separation method, since the nature of the substance called sludge is dull, the same electrophoresis is carried out. However, when the sludge is put into water and the particles fall, the electricity is applied horizontally. Separation means is used to collect heavy metals on the cathode side and discharge them.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that when sludge is put into water from above, electricity flows from a horizontal direction when particles settle, heavy metals are gathered to the cathode side by the force, and the remaining sludge is discharged together with water. The basic idea is that heavy metals will be reduced from the understanding. Since the basic theory regarding electrophoresis is used as it is, details of the theory are omitted. In the case of separating sludge, the electrolyte is replenished and the amount required for electrophoresis is mixed because the electrolyte is insufficient in the water quality as it is.

Description of basic technology (technical inventive step, novelty) When sludge is discharged from the water, the particles sink down due to the difference in specific gravity with water, and at that time, when electricity flows from the horizontal direction, heavy metal Are moved to the cathode side. This is a new technology that combines the principle of particle settling and the principle of attracting to the cathode side by electrophoresis. (Combined Use of Electrophoresis and Precipitation for Separation and Separation) In the method of separation, the present invention is basically a different idea from the method of squeezing which is positioned as the separation and separation. (Difference between movement by electrophoresis and squeezing) This is a new technology that uses a natural providence that separates and discharges a wall near the bottom so that heavy metals do not mix with the precipitate. The ion-permeable membrane, which is tentatively referred to as a precipitation electrophoresis combined separation method and hereinafter referred to as a combined method, will be described in comparison with the technology of Japanese Patent Application No. 11-33595 (hereinafter referred to as a membrane type). 1. Due to the nature of what is called sludge, the clogging of the membrane is an important requirement, and it is easy to cover the eye area with other materials. Problems do not surface, but when dealing with large quantities,
The combination method has an advantage because it is an unavoidable problem. 2. It is described that sludge can be separated in slurry form, but it is possible to do it, but it requires transfer energy for ionized molecules to displace other substances and reach the cathode. Energy is needed to get through. Therefore, there is an advantage in the combined use method in which sludge is mixed with water and moved when settling. (The general interpretation of slurry is to remove water from the sludge, and the state of about mayonnaise is said to be slurry.) The reason is that water secures the space where ionized material can pass freely, so it is pushed away The combined system has an advantage because the energy of the movement for the movement and the energy of the movement for passing through the membrane are reduced. (It is possible to move in granular form.) 3. The above-mentioned design is linked to the sludge treatment time, so the combination type is superior in treating sludge in a short time. Considering the time until the heavy metal is ionized and the time until the ionized material reaches the electrode, the amount of mechanical force in electrophoresis is considered to be not so large, which is superior to those without obstacles. There is. Naturally, it cannot be specified by the type of heavy metal, the size of the particles, the amount of electricity to be applied (Coulomb value), etc., but a time loss of pushing an obstacle can be considered. The shorter the processing time is, the more advantageous it is. Therefore, the combination type has an advantage. 4. Regarding the matter of flowing a large amount of water on the cathode side to secure the electrolyte, other technologies (production of electrolytic water) use potassium chloride (KCl), sodium chloride (NaCl salt), etc. as the electrolyte. Improving electrical conductivity by adding electrolyte to sludge is a technique in combination with other techniques. Improving the conductivity in water does not hinder the ionization of heavy metals, but the substance is also an electrolyte, so the term synonymous with electrolyte was used. (Underwater conductivity improver) 5. The inferiority of the combined type between the membrane type and the combined type is that sludge is mixed in regardless of the cathode side. Alleviate the problem. (The combined use type is inferior to the membrane type in terms of the separation accuracy on the cathode side.) It is also possible to increase the accuracy by passing the material from the cathode side through another combined device again. 7. Since there is no problem with the separated anode-side discharge, there is a feature in securing an absolute condition amount.

[0007] Scope of sludge [0007] What is usually called sludge is defined as dirty sludge. In the present invention, the sludge described below is defined as sludge. 1. Sediment discharged from sewage treatment and water treatment 2. Sediment dredged from rivers, swamps, canals, and dams 3. Incinerated ash dissolved in water to remove heavy metals 4. Agricultural land, residential area Dissolved in water to remove heavy metals in general contaminated soil such as

Hereinafter, a specific description will be given with reference to the drawings. FIG. 1 is a perspective view of a skeleton constituting the whole. Electrodes are attached to both side walls of the tank, wiring is provided between the electrodes, and a DC power supply is provided between the wirings. Connect the power supply. Connect the power supply to the one marked with a circle. It is important that the electrode plate is attached to the entire surface of the tank, and when electricity flows, it is important that the current flows from surface to surface. Therefore, it is not preferable because the ionization becomes uneven in the portion where the current is not applied and the movement of the heavy metal becomes uneven. Although not an absolute condition, it is assumed that the current flows in a straight line from the anode surface to the cathode surface in a normal state. A pipe for sludge water is provided from the upper surface of the tank, and the sludge water is put in. The heavy metals attracted to the cathode are discharged from the pipe (4) that discharges the water together with the water, and the remaining sludge water is discharged from the pipe (5). I do. The amount to be injected and the amount to be discharged are the same, and the discharge on the cathode side and the discharge on the anode side are 1: 5
The discharge on the anode side is increased at a ratio of about 1:20. A valve is provided for each pipe to adjust the flow rate. The same is true even if the inflow is adjusted with a water level sensor. FIG. 2 and FIG. 3 are schematic cross-sectional views in which the sludge water is continuously put into the tank, and electricity is supplied when the sludge water is discharged. FIG. 2 shows that heavy metals are attracted to the cathode side from the sludge water and settle without being attached to the electrode and settle down. It is described that the remaining sludge is discharged from the anode side together with water. The projections are provided at the bottom of the tank, so that even if heavy metals settle, it does not go to the anode side, and it also expresses that sludge mixes on the cathode side. Therefore, the reason why the discharge amount of the cathode and anode is made different can be understood. What is important here is that heavy metals are removed on the anode side, and there is little problem that sludge is mixed with heavy metals on the cathode side. The reason is that only the discharge on the cathode side can be separated again in another tank. (2 devices
Separation can be performed sequentially in stages or in multiple stages, and the amount discharged is reduced in order. The anode side after the second stage can be returned to the previous stage in order. (FIG. 10) FIG. 3 shows the state of change when salt is added to sludge water and then flows. Ionization becomes uniform by expressing that electricity is uniformly applied to the sludge water. The surface layer is a saline solution area, the anode side becomes more acidic as it goes down, the cathode side becomes more alkaline as it goes down, and in the middle of both poles at the bottom part, there is a shortage of electrolyte and electricity is generated. It expresses the state of flowing around. As for the inlet, as shown in Fig. 4, the water is discharged from the circumferential direction of the pipe.
By this, it was expressed that the sludge water was distributed and supplied in the horizontal direction. 2 and 3 are phenomena occurring at the same time, but are shown in two drawings for easy understanding.

In FIG. 5, the basic concept and the basic principle
08), except that the electrode rod is provided at the center and the periphery thereof is provided as an electrode plate by making it cylindrical. To explain the configuration, an electrode rod (21) is provided at the center of the axis of a cylindrical tank (11), an electrode plate (3) is attached in a circumferential direction inside the tank, and the electrodes are connected by an electric wire (8). In the meantime, a power source (9) is arranged, a funnel (53) is attached below the electrode, a discharge pipe (5) is inclined downward from the lower part of the funnel, and the pipe is extended to the outside of the tank. A flow control valve (51) is attached to the part, the bottom of the tank is shaped like a funnel, a discharge pipe (4) is mounted at the bottom, a flow control valve (41) is mounted in the middle, and an injection pipe ( The injection port (73) of 7) is attached, and the flow control valve (72) is attached to the injection pipe. When the injection pipe is installed, it is more effective that the sludge water is settled while rotating by installing the injection pipe so as to be inserted from the tangential direction of the tank. The direction of rotation is desirably left rotation when viewed from above. (In the case of the northern hemisphere of the earth) Since the water is drained from the container, counterclockwise is good. At this time, with the electrode plate inside the tank as the anode and the electrode rod as the cathode, electricity flows between the electrodes to attract and discharge heavy metals. By passing electricity from the circumference to the center, the current density increases near the electrode rods, and heavy metals can be strongly attracted, resulting in high efficiency. This is a great merit not found in the rectangular tank (described above). Speaking of what happens to a polygonal tank, a circle is good because the ultimate polygon is a circle. (Cylindrical is also advantageous in terms of rotation.) Even in a rectangular shape, there are disadvantages such as no rotation and the distance between the electrodes is different, but since it is concentrated at the center, the attractive force is strong, so it can be used. The inlet is merely a cut of the pipe, but a cut of a cross section determined so that the flow velocity at the outlet is about 2 m / s. (If it is too slow, it will not be given a turning force, and if it is too early, the water in the tank will splash and be wasted.)

In the gutter type, the basic concept and the basic principle are taken over from the description so far. However, if the direction display in FIG. 1 is used, the one in which the Y direction is large and the XZ direction is small is replaced with the name of a gutter. . The different features are described in 1 and 2 below. 1. The idea is to increase the ionization efficiency by applying a current density (passing electricity) to the sludge particles that settle at the bottom part due to the short distance from the water surface to the bottom, and settle. (Surface current is a bypass current.) 2. Sludge water flows downstream while electrolyzing and precipitating, but it is better to add the electrolyte according to the degree of decomposition than to add the entire amount of electrolyte first. The amount to do is small. To explain the configuration, the gutter (12) is installed with a gradient, and several electrode rods (21) are installed continuously on one side of the side surface.
Similarly, an electrode rod (31) is arranged on the opposite side, and the electrodes facing each other are connected by an electric wire (8). A power supply (9) and an ammeter (91) are attached between them, and the current between each electrode is set. A motor-operated valve (101) corresponding to the amount is provided, and a pipe (10) for injecting an electrolyte is provided. The bottom of the gutter has a horizontal protuberance on the upstream side and a convex (6) protruding in the axial direction from the middle. The outlet is maximized near the outlet and each outlet is provided at the bottom. In the tank type, the idea is to separate the current by flowing an electric current while the particles fall, and in the gutter type, the idea is to separate the current by flowing the electricity while dropping at the bottom part that has fallen down. It is a method and device for transforming the basic idea. In the cathode, there are those where heavy metals adhere and those which precipitate, but it is convenient to remove the stuck part with physical force, since it is shallow. Which of the tank type and the gutter type is better depends on the type and content of heavy metal contained in the sludge, the amount of sludge to be treated, and the like.

Description of common items 1. Since electrophoresis is used, some of the metals are faster and others are slower. 2. Electricity is applied to all the metals in the sludge, so the type of metal cannot be selected. (Since it changes in descending order of ionization tendency, direct selective separation is not possible. Among elements required for plants, calcium K and calcium Ca also move to the cathode side.) Heavy metals have a low ionization tendency, so If the standard is adjusted, K, Ca, etc. will move before that, so this device and this method cannot perform a single selective separation. However, if the current value is lowered before removing heavy metals, K , Ca, etc. can be extracted to some extent. (Claim 10) (Pretreatment device, shown in FIG. 10) 3. The amount of ionization is determined by the product of flowing current and time. (Coulomb value) (The amount of current that can flow between the electrodes underwater is increased by adding an electrolyte.) 4, The voltage between the electrodes measures the amount of heavy metal discharged from the anode side, and Determine the voltage according to the numerical value.
(Claim 3) 5, Some of the cathodes are those to which heavy metals adhere and others are precipitated. 6. If there is too much adhesion, there is also one that lowers the electrical conductivity (eg, calcium). Periodic cleaning such as reverse voltage, pickling, and brushing is required. The present invention is described in claim 11. By limiting the amount of adhesion to the cathode by repeating the application of a reverse voltage for a short period of time periodically, since maintenance and management can be performed without changing the device itself, it is effective. 8. When metals are used on the anode side, the elution phenomenon (electrolytic corrosion) occurs due to the release of ions. (Reduction is possible by using a metal with a low ionization tendency.) 9. Since gases such as chlorine, hydrogen, and oxygen are emitted from the tank, it is necessary to take measures. 10. Bacteria, insects, insect eggs, and plant species in the sludge are altered or killed by electrophoresis. (There is an example where it is used as a sterilization method in other fields ... It is considered that cells are also electrolyzed.)

Description of the material and the necessity of the method and apparatus. The sludge described in the preceding paragraph (10), which combines insecticide, sterilization, and heavy metal removal, is considered to be valuable as a new material. It is basically used in the agricultural field and its value as 1, 1, as a vegetation material for organic agriculture 2, as a basic material for compost and compost 3, as a material to make charcoal by steaming sludge As mentioned above, by removing heavy metals and sterilizing and killing insects, it is regarded as a basic agricultural material in a different sense from sterilization and killing by chemicals or heating. To add further, it goes without saying that the place where sludge itself is dumped has reached its limit, and it is needless to say that the act of throwing sludge is not going to go. Incineration is not a good thing for the global environment because it uses fuel and emits carbon dioxide. Therefore, there is no value in discarding even “hed” or “sludge”, and it is meaningful to be able to use it, and the inconvenient part (with a large amount of organic matter) ( Sludge from which heavy metals, pests and pathogens have been removed is valuable. For preservation, it can be said that the sludge is detoxified by adding useful bacteria in an amount sufficient for preservation and protecting it from other malignant bacteria. This sludge is tentatively called “detoxified sludge” and will be described. Limiting the growth of malignant bacteria with benign bacteria is a concept similar to microbial pesticides. Bacterium, YOK, E
It is useful as a new material because it functions effectively because there are examples of the existence and use of M bacteria and the like. (Aerobic, anaerobic or anaerobic bacteria are good.) A familiar example is "natto", and it is known that bacteria control other bacteria in preference to other bacteria. Therefore, detoxified sludge is a new material. Storing sludge containing a large amount of short-term decomposition components in a sterile state for a long time may explosively increase due to other germs, and therefore a method of storing bacteria is necessary for a sterile state.
(Progress of decomposition by useful bacteria does not hinder) Especially in an anaerobic condition, methane gas and hydrogen sulfide gas may be emitted, and care must be taken for the propagation of malignant bacteria. Therefore, it is important to protect by adding benign bacteria . Dry storage can be considered as a matter of course, but in comparison with that, the cost of drying is added to the price, and even if it is detoxified sludge, it loses economical efficiency. However, it is desirable to preserve it as it is, and for that purpose, it is useful to preserve it with useful bacteria. Originally, sludge is a name to be discarded, and it is necessary to give an alias to use it. As a culture medium for nutrient cultivation, which has been applied by the applicant under the condition that heavy metals are removed from the sludge, Japanese Patent Application No. 11-18223.
1. As a method for decomposing organic substances, Japanese Patent Application No. 11-21572
0, which is related to the above two applications, and is a material that gives value to use and contributes to environmental preservation through use. Even when charcoal is made by steaming sludge, it is more efficient to remove heavy metals first. (Electrophoresis takes time afterwards.) When sludge is incinerated, heavy metals are contained in the ash, so heavy metals should be removed from the ash regardless of whether it is used or discarded. Even if the sludge is discarded or buried, it is likely that if heavy metals are not removed, it will penetrate into groundwater in the future, and it is desirable to remove it regardless of whether there is a law.

Since the present invention utilizes electrophoresis and sedimentation, the size and the like are limited. Therefore, approximate numerical values and explanations will be given below. 1. The distance between the electrodes is about 150 mm or more and about 5000 mm or less. 2. The water depth of the tank is about 500 mm or more and about 8000 mm or less. 3. The voltage applied between the electrodes is about 5 V or more and about 400 V or less. 4. The mixing ratio of the electrolyte is about 0.01% or more and about 15% or less. (Weight ratio to water) (Electrolyte concentration and energization performance are not proportional at high concentration, so waste and harm occur.) 5, Mixing ratio of sludge and water (sludge concentration) is about 0, 1% or more and about 25% Less than. (The sludge is converted to the weight when it is in a dry state.) 6. The capacity of the tank is about 20 minutes or more of the inflow (outflow) water volume.
Less than about an hour. 7. In the gutter type, the slope of the gutter is about 1/300 or more and 1 /
Less than about 100. 8. In the gutter type, the length of the gutter is about 5 m or more and about 50 m or less. 9. The time for applying the reverse voltage is about 0.5 seconds or more and about 120 seconds or less. 10. The switching interval from the normal voltage to the reverse voltage is 10 seconds or more and 10 minutes or less. The reverse voltage is delicately balanced depending on the distance between the electrodes, the distance to the bulge, the type of heavy metal in the sludge, the concentration, etc., so it cannot be specified, but it is indirectly related to separation, but restricts adhesion to the cathode side. Therefore, it is better that the reverse voltage time is small, and the adhesion state is measured to determine the interval, the reverse voltage time and the interval. (Ionization is the same with reverse voltage.) Instead of reverse voltage, an alternating current can be passed. As a pretreatment device, there is a method in which the attached matter is extracted into K and Ca first, and then combined as a dedicated device for removing heavy metals. In order to treat a large amount of sludge, there is also a time constraint (the amount to be treated per day). Therefore, the method is set to one unit and a plurality of units are provided.

A flow sheet of an apparatus for removing heavy metals from sludge will be described with reference to FIG. 1. It is expressed that a plurality of primary processing units are provided to cope with the processing capacity. 2. Expressing that the sludge on the cathode side is collected by the secondary treatment device. 3. Expressed that the accuracy of sludge on the cathode side was increased and collected by the tertiary treatment device. 4. Expressing that useful elements are recovered from the cathode side by the pretreatment device. 5. The fact that the exit is large or small expresses that the amount of emission on the cathode side is small. Although the primary treatment was expressed as a continuous treatment from the first to the fourth, the primary purpose is to remove heavy metals from sludge, so primary treatment is sufficient. However, in order to increase the separation accuracy of heavy metals, a secondary or tertiary device is required. Was linked.

An outline of the operation of the apparatus will be described with reference to a flow sheet shown in FIG. 1. In the drawing, the detection part is represented by a double circle, the corresponding control parts are represented by a circle X, the dotted arrows represent the cathode side discharge, and the solid lines represent the anode side and other flows. . Those connected by dotted lines represent the related states. 2. In the mixing and mixing tank, mix the sludge and water, stir it,
It expresses that the concentration of the whole tank becomes uniform. 3. It expresses that the concentration of electrolytic water is adjusted to a predetermined concentration in the mixing and stirring tank. 4. In the primary treatment, measure the heavy metals in the sludge discharged from the anode side, adjust the voltage, adjust the amount of inflow and outflow, and adjust the ratio of the discharge of the anode and the cathode. Expressed that it is possible. The same applies to the fifth, second, third, and n-th (n is the last number sign in the case of a large number), but is abbreviated. 6. In the extraction process, detection is performed on the cathode side, but the amount of electricity and the flow rate are kept constant, and K and Ca are taken out. Therefore, when heavy metals are detected, the voltage is lowered. (Pretreatment separation device) 7. Since the amount of ionization is determined by the amount of current (current × time), all applicable matters can be varied, but usually fixed in order as follows. B. The size and number of primary treatment units based on the amount of sludge to be treated in the initial plan. B. Distance between electrodes and normal dimensions depending on the size of the device. C, Approximate flow rate and diameter depending on the throughput of one device. D. Equipment order based on initial plan. E. Temporary setting of voltage and adjustment of valve opening / closing by test operation. Therefore, the variables that can be changed in the normal device are the valves corresponding to the voltage and the aperture, and it is not impossible to change in other parts. However, the anode side detection can be handled by changing the voltage. Is appropriate. In an emergency, close the valve. cathode,
The discharge rate of the anode is adjusted by a valve. Voltages are handled by adjusting the number of power supplies arranged in series and connected in order.

Additional Description of Sludge and Electrophoresis The form of heavy metals contained in sludge is not uniform but is shown below. 1. Exist as metal particles (including as compound) 2. Attach to or partially exist on inorganic and organic substances 3. Exist in an almost even state in inorganic and organic substances (including in shells) From the above facts, it is considered that the materials 1 and 2 ionized in a short time can be moved to the cathode side by electrophoresis, and those in the uniform state of 3 are moved to the cathode side together with the particles in this method. Since the metal particles are ionized, swim in water, and reach the electrode, this is a setting condition that can be implemented in combination with sedimentation and separation. Under conditions of attachment and partial presence, ionized particles
It requires time to move away from the original particle. Of course, it cannot be specified depending on the way of existence, its quantity and its type, but it often leaves. (If not separated, proceed to the following description.) If the particles exist uniformly or close to each other, or if they are wrapped in a shell, etc., the metal content in the whole particles is ionized. Since the electrophoresis reaction starts from, this is achieved by reducing the resistance when moving. Therefore, a slurry or a membrane for separation is an obstacle. Naturally, it is conceivable that a component that goes to the anode side exists in these particles, and if the cathode side wins in the cathode side, the anode side, and the tug-of-war state, it moves to the cathode side. Therefore, the amount of the mechanical force of electrophoresis is originally small, and when a tug of war is performed inside the particles, the force becomes weaker and more so that the sludge particles are suspended in the water, ionized before falling, and thought to swim toward the cathode side. Is effective for sludge. Naturally, there may be particles containing heavy metals that go to the anode side after losing the tug of war. To compensate for this, the device detects the amount of heavy metals and changes the amount of current by changing the voltage to promote and adjust ionization. Since the description is related to the whole, the description is divided into two parts.

Example 1 In an existing sewage treatment facility and a newly constructed sewage treatment facility, an anode plate is attached around the inside of a sedimentation tank, a cathode electrode rod is attached in the center, a container is attached below the electrode rod, and the anode is switched to the cathode. The configuration that conducts electricity is effective in sewage treatment facilities.
As a sewage treatment facility, it is a matter of permission and approval, so it is necessary to keep the basic structure unchanged. (Whether the above configuration is acceptable or not depends on the judgment of the responsible officer.) The sludge in the existing sewage treatment plant contains heavy metals, so even if it is incinerated, there is a higher concentration of heavy metals in the ash. included. (Absolute values are almost the same.) The sewage treatment equipment separates water and sludge by sedimentation, so heavy metals can be separated by passing electricity through the sewage treatment plant. The performance of the apparatus is that there are few restrictions on time, there are disadvantages in that there are many rectangular sedimentation tanks, so there are some difficulties at the corners, and that rotation sedimentation cannot be performed. 11 and 12 show the outline of the apparatus. Here, the difference is that the discharge device is not provided from the cathode side, but is stored in a container, and when the sludge is extracted, the entire container is lifted and discharged. A large-scale treatment facility requires a device for automatically or forcibly extracting sludge containing separated high-concentration heavy metals. However, since it is assumed that the sludge is extracted from the container, it is omitted in the drawing. (Equivalent to the device described in the cylindrical processing device) Put the substance attached to the electrode rod and the surroundings into the container,
The mouth of the container has a cross section of about 2 to 5 times the cross section of the electrode rod. Example 2 Cadmium was detected in rice when a paddy field was contaminated with heavy metals. As a response, cadmium in the soil was removed by mounting the device on an agricultural machine and moving the device. It's best to treat the soil after "Shirokaki" at the right time. It is appropriate for the apparatus to be separated stepwise as shown in FIG. A method in which muddy soil is pumped up and returned to paddy fields while being processed. Pests, eggs of pests, and diseased bacteria are killed by electrophoresis in paddy soil. Example 3 Weeds and weed seeds can be expected to be killed to some extent during the "white-swing" period, so that it is effective as a weeding method without using a herbicide. Since pests and pathogens of plants are expected to increase explosively due to temperature conditions and the like, this device does not function absolutely, but has a function of cutting off (reducing) the origin. The above items can also alleviate problems such as residual pesticides to some extent. Example 4 Although ionization of heavy metals and electrophoresis are phenomena occurring at the same time, a method in which an ionization step is performed first, and then precipitation and electrophoresis are separated in a tank or a trough. The feature is that in the ionization of heavy metals, there is no distinction between direct current and alternating current, and if there is interference of electricity, ionization will be performed, so it is possible to use alternating current and electricity. Can be changed relatively easily. The type of heavy metal in the sludge to be removed, the concentration, the state of distribution, and the amount of temporal treatment to be treated are to be selected.However, this method has a large amount of heavy metals with a low tendency to ionize heavy metals. This is effective when the particles are in the state of getting inside the particles.
This is effective for sludge which is regarded as having poor conditions, and is characterized in that the apparatus can be reduced in size. Although the ionization apparatus is not particularly limited, it is natural that the apparatus is installed in front of the separation tank. There is a case where it is installed in a tank that mixes sludge and water, and a case that it is installed in a pipe that goes to a sedimentation tank. As a matter of course, since electricity is passed between the electrodes for separation to separate them, ionization is also performed there. The only difference is how to do the main ionization. (The basic idea is the same)

[0018]

According to the apparatus and method, heavy metals in sludge can be removed in a short time. Although there is a limitation in one device, the amount can be increased by combining in parallel, and the accuracy can be improved by combining in series. It can also be used as an extraction device for calcium, which is a useful element as a fertilizer. If this device is used, bacteria, insects, insect eggs, etc. contained in the sludge will die. Similarly, plant species die or degrade and have a herbicidal effect. It is a socially important invention because it effectively avoids incineration and burial by effectively utilizing sludge and contributes to environmental preservation.

[Brief description of the drawings]

FIG. 1 is a perspective view of a skeleton showing a configuration of the present invention.

FIG. 2 is a schematic sectional view showing a state of separation according to the present invention.

FIG. 3 is a schematic sectional view showing a state of a decomposition solution of the present invention.

FIG. 4 is a cross-sectional view of the injection port of the present invention.

FIG. 5 is a perspective view of a skeleton showing a configuration of a cylindrical tank of the present invention.

FIG. 6 is a sectional view showing a configuration of a cylindrical tank of the present invention.

FIG. 7 is a skeleton showing a gutter type configuration of the present invention.
It is a perspective view.

FIG. 8 is a sectional view showing a gutter type configuration of the present invention.

FIG. 9 is a schematic sectional view of each section showing a gutter type separation state of the present invention.

FIG. 10 is a process explanatory view (flow sheet) of the present invention.

FIG. 11 is a plan view showing the first embodiment of the present invention.

FIG. 12 is a cross-sectional configuration diagram illustrating Example 1 of the present invention.

FIG. 13 is a process explanatory view (flow sheet) of the present invention.

[Explanation of symbols]

 1,11 tank 2,21,3,31 electrode 4,5 discharge pipe 41,51 valve 53 funnel 54 container 6 uplift 7 injection pipe 71,73 injection port 72 valve 8 electric wire 9 power supply 91 ammeter 10 pipe 12 gutter 101 electric valve

Claims (13)

[Claims] 1. A tank (1) in which sludge diluted with water is continuously prepared.
An electrode plate (2) is provided on any side of the tank, an electrode plate (3) is mounted on the opposite side, and a DC voltage is applied between the electrode plates. Discharge ports are provided at the lower part to discharge continuously, and when sludge particles settle, heavy metal collects on the cathode side due to the current flowing between the electrodes, so that the cathode side and the anode side are separated and discharged separately. The method of removing heavy metals in sludge is characterized by the following. 2. The method for removing heavy metals from sludge according to claim 1, wherein an electrolytic substance is added to the sludge water. 3. A method for removing heavy metals from sludge, comprising measuring the amount of heavy metal in sludge discharged from the anode side and setting a voltage corresponding to the value. 4. An electrode plate (2) is provided on the side surface of a rectangular tank (1), and an electrode plate (3) is mounted on the side surface of the opposite tank, and the electrodes are connected by an electric wire (8), and a power supply is provided therebetween. Discharge pipe (4) is placed at the bottom of the tank in which (9) is placed and both electrodes are installed.
Attach (5), and flow control valve (41) on the discharge pipe
(51) is attached, and the bottom of the tank is
A ridge (6) for collecting sediment is provided, an injection port (71) of an injection pipe (7) is attached above the tank, and a flow control valve (73) is attached to the injection pipe. , Equipment to remove heavy metals in sludge. 5. An electrode rod (21) is provided at the center of the axis of a cylindrical tank (11), an electrode plate (3) is attached in a circumferential direction inside the tank, and the electrodes are connected by an electric wire (8). , A power supply (9) is arranged between them, a funnel (53) is attached below the electrode, and a discharge pipe (5) is inclined downward from the lower part of the funnel and piped out of the tank. Flow control valve (5
1), the bottom of the tank is funnel-shaped, and a discharge pipe (4) is attached at the bottom, and a flow control valve (41) is installed in the middle.
And the injection port (7) of the injection pipe (7) above the tank.
3) A device for removing heavy metals in sludge as described above, wherein a flow control valve (72) is attached to an injection pipe. 6. The gutter (12) is installed with a gradient in the longitudinal direction, several electrode rods (21) are continuously installed on one side, and the electrode rod (31) is also arranged on the opposite side. A voltage is applied between the opposing electrodes, and the substance dissolved in the sludge water is allowed to flow from the upstream of the gutter, and heavy metals are collected and flowed down to the cathode side, and are discharged from each outlet of the cathode and anode at the bottom. A method for removing heavy metals in sludge characterized by the following. 7. The gutter (12) is installed with a gradient in the longitudinal direction, several electrode rods (21) are continuously installed on one side, and the electrode rod (31) is also arranged on the opposite side. Then, the opposing electrodes are connected by an electric wire (8), a power supply (9) and an ammeter (91) are attached between them, and an electrolyte is injected corresponding to the amount of current between each electrode. The method for removing heavy metals in sludge according to claim 6. 8. A gutter (12) is installed with a gradient in the longitudinal direction, and several pole bars (21) are continuously installed on one of the side surfaces.
Similarly, an electrode rod (31) is arranged on the opposite side, and a wire (8) is connected between the opposing electrodes, and a power supply (9) and an ammeter (91) are attached between them, and a current amount between the electrodes is measured. A motor-operated valve (101) corresponding to the above is provided, and a pipe (10) for injecting the electrolyte is provided. The bottom of the gutter is horizontal at the upstream side and has a convex (6) that is convex in the axial direction from the middle. A device for removing heavy metals in sludge, configured as above, with a maximum near the outlet and a respective outlet at the bottom. 9. Removal of heavy metals in sludge, characterized by increasing the precision of removing sludge containing heavy metals from the sludge containing heavy metals by separating the separated sludge containing heavy metals on the cathode side again by a separation device. Method. 10. A method for removing heavy metals in sludge, characterized in that the amount of current flowing when sludge is separated is reduced to preferentially extract those having a high ionization tendency. 11. A heavy metal in sludge characterized by restricting the amount of heavy metal adhering to the cathode side by applying a voltage applied between the electrodes by periodically reversing the voltage for a short period of time to energize the sludge. Removal method. 12. A method for removing heavy metals from sludge, sterilizing and killing insects, killing insect eggs, killing plant seeds, and removing a sufficient amount of useful bacteria from the sludge for preservation. Detoxified sludge characterized by limiting the growth of other bacteria when added. 13. A method for removing heavy metals from sludge, comprising the steps of: ionizing heavy metals in a first step in separating heavy metals in a sludge; and separating and discharging the sludge in a second step by precipitation and electrophoresis.