JP2006000718A - Magnetic separation and cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic separation and cleaning apparatus constituted so as to recycle a flocculant and a magnetic powder to reduce an operation cost and capable of preventing the increase in a suspended particle [SS(Suspended Solids)] component and a rise in pH in the system to enhance the quality of treated water. <P>SOLUTION: A sludge decomposition tank 12 for adding hydrochloric acid 13 to magnetic flocs 10 to stir the flocs and a sedimentation tank 14 for separating the treated liquid decomposed by hydrochloric acid 13 on the basis of specific gravity are provided to the magnetic separation and cleaning apparatus and a turbidity meter 29 is provided to a piping line of treated water 17. The concentration of the suspended particles (SS) is controlled by an automatic valve 19 and the amount to be added of sodium hydroxide 21 is controlled by a pH meter installed in a stirring tank 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sludge recovery technique for easily decomposing sludge and reusing magnetic powder and aggregating agent from sludge in a magnetic separation and purification apparatus for water purification.

  For the purpose of water purification, a thin wire net or a net woven with polymer fibers is used as a separation membrane. A flocculant and magnetic powder are added to raw water with contaminated particles to generate magnetic floc, and the magnetic floc is formed with a membrane. A magnetic separation and purification device for recovering high-concentration sludge by separating and removing magnetic flocs separated and collected by a film by a magnetic field generating means is known in Japanese Patent Application Laid-Open No. 2002-273261. This membrane separation and purification device is composed of a stainless steel fine wire or a net of polyester fiber or the like, and has a membrane separation portion having an opening with an opening of several tens of micrometers, for example. In order to separate fine pollutants smaller than the opening, for example, flocculant vanous sulfate, polyaluminum chloride, iron chloride, and magnetic powder are added to the raw water and stirred in advance, so that fine solid suspensions and algae in the raw water Then, a magnetic floc in which microorganisms are bound to a size of about several hundreds of micrometers by a flocculant is formed. This magnetic floc cannot pass through an opening having an opening of several tens of micrometers, and is collected and separated at a high removal rate. The treated water that has passed through the membrane is further purified.

  On the other hand, the magnetic flocs collected on the membrane are washed away from the membrane with washing water, then stopped near the water surface, separated by the magnetic force of a magnet placed stationary near the water surface, and sludge collected by the sludge transfer means Stored in the tank. Ultimately, the sludge is usually transported to a disposal site or incinerator by a truck or composted.

JP 2002-273261 A

  However, in the above prior art, the point that the flocculant and the magnetic powder are recovered from the sludge and reused is not sufficiently considered.

  The object of the present invention is to recycle and recycle the flocculant and magnetic powder to reduce the operating cost of the apparatus, and to prevent the suspended particles (SS (Suspended Solids)) component and pH in the system from rising. An object of the present invention is to provide a magnetic separation and purification device that can improve the quality of treated water.

  In order to achieve the above-mentioned object, the present invention supplies a magnetic substance and a flocculant to a fluid to be treated containing the substance to be removed, and stirs the substance to be removed by the magnetic substance and the flocculant. A first agitation tank to be agglomerated, and a filtration tank for obtaining treated water by filtering the fluid to be treated containing the agglomerated substance introduced from the first agitation tank by a filtering means having an opening through which the agglomerated substance cannot pass And a sludge collecting means for magnetically collecting and collecting the agglomerated material collected by the filtering means, and adding and stirring hydrochloric acid to the agglomerated material collected by the sludge collecting means 2 and a settling tank for separating the agglomerated material decomposed by the hydrochloric acid into a magnetic substance, an aggregating agent, and an object to be removed, and returning the magnetic substance and the aggregating agent separated by the settling tank to Supplied to the first agitation tank Serial characterized by being configured to reuse added to the treatment fluid.

  Further, the present invention provides a turbidity meter for measuring a suspended particle concentration in treated water obtained by filtration from the filtration tank in the magnetic separation and purification device, and the suspended particle concentration measured by the turbidimeter. When the concentration exceeds the reference concentration, at least suspended particles are discharged from the settling tank to the outside of the system.

  Further, the present invention provides a turbidity meter for measuring a suspended particle concentration in treated water obtained by filtration from the filtration tank in the magnetic separation and purification device, and the suspended particle concentration measured by the turbidimeter. When the particle concentration exceeds the reference concentration, suspended particles are discharged from the precipitation tank to the outside of the system, and for the magnetic powder discharged together with the suspended particles during the discharge, the magnetic powder recovery provided downstream of the precipitation tank is performed. It is configured so as to be recovered in the tank and returned to the fluid to be treated supplied to the first stirring tank.

  In the magnetic separation and purification apparatus, the present invention is characterized in that a pH meter is provided in the first stirring tank, and the pH of the first stirring tank can be adjusted by an instruction from the pH meter.

  According to the present invention, flocculant and magnetic powder can be recovered and reused by decomposing and sedimenting sludge with hydrochloric acid, so that it is possible to reduce the operating cost of the apparatus and Suspended solids (SS) concentration and pH can be stabilized, and the effect of improving the quality of treated water is achieved.

  An embodiment of a magnetic separation and purification device having a sludge recovery function according to the present invention will be described with reference to the drawings.

  That is, the present invention is a magnetic separation and purification apparatus shown in each of FIGS. 1 to 3, in which a flocculant is combined with a small amount of hydrochloric acid 13 that causes sludge decomposition and a precipitation tank 14 that consumes little power. The recovery of the magnetic powder was realized, and the quality of the treated water was improved by the control by the turbidimeter 29 and / or the pH meter 22.

[First embodiment]
A first embodiment of a magnetic separation and purification apparatus according to the present invention will be described with reference to FIG. FIG. 1 shows the flow of the sludge recovery function in the first embodiment of the magnetic separation and purification apparatus. The raw water (processed fluid) 1 containing contaminated particles that are to be removed such as oil is preliminarily mixed (supplied) with an appropriate amount of coagulant (for example, vanous sulfate, polyaluminum chloride or iron chloride) and magnetic powder. The rotational speed is relatively low (the peripheral speed of the blade is about 1 m / s to 2 m / s) and is introduced into the agitation tank 3 to form a magnetic micro floc of about several hundreds of micrometers. The peripheral speed of the blade is about 0.5 m / s to 1 m / s). In the agitation tank 4, the polymer flocculant 2 is added to form (generate) a magnetic floc (aggregated substance) 10 having a size of about several millimeters by the flowed magnetic micro floc. The magnetic floc 10 and the pretreatment water generated in this way are introduced into the next filtration tank 5.

  In this way, the magnetic substance and the flocculant are supplied to the raw water (processed fluid) 1 containing the substance to be removed, and the magnetic substance is floculated (aggregated substance) with the magnetic substance and the flocculant by stirring. The first agitation tank to be aggregated into 10 is constituted by the agitation tanks 3 and 4.

  The filtration tank 5 is provided with a rotating drum 6, and the outer peripheral surface of the rotating drum 6 is a mesh (for example, a stainless steel fine wire, polyester fiber, or the like having a mesh having an opening of several micrometers to several tens of micrometers) Filtration means) 6 'is provided. Therefore, the pretreatment water that has flowed into the filtration tank 5 passes through the net 6 ′ and flows into the rotary drum 6. At this time, the magnetic floc (aggregated substance) 10 in the pretreatment water is collected by the net 6 ′. Then, the purified water (treated water) 17 that has passed through the net 6 ′ is discharged from an appropriate opening of the rotary drum 6 and discharged outside the system.

  On the other hand, after the magnetic flock 10 collected and adhered to the net (filtering means) 6 'is washed out from the net 6' by ejecting washing water (not shown) from a nozzle provided inside the rotary drum. The magnetic field generating means 8 is retained in the vicinity of the water surface and is stationaryly disposed near the water surface, and is attracted to the surface of the rotator 7 by, for example, a superconducting magnet or a permanent magnet. It moves in the direction of the scraping means 9 such as a scraping plate. The moved magnetic floc 10 is peeled off from the surface of the rotating body 7 by the scraping means 9 and is naturally dropped and stored in the sludge collecting tank 11. The magnetic floc 10 stored in the sludge recovery tank 11 to some extent is transferred to the next sludge decomposition tank 12. The sludge collecting means for magnetically collecting the magnetic floc (aggregated material) 10 collected by the net (filtering means) 6 ′ in this way is collected by the rotating body 7, the magnetic field generating means 8, the scraping means 9 and the sludge collecting means. It is composed of a tank 11.

  In the sludge decomposition tank (second agitation tank) 12, the polymer flocculant is decomposed by adding an appropriate amount of hydrochloric acid 13 while stirring the transferred magnetic floc 10, for example, agglomeration containing oil and treated water. Decomposed into agent and magnetic powder. The pH of the hydrochloric acid to be added depends on the state of the magnetic floc 10, but is preferably in the range of 1.5 to 4. If the concentration of hydrochloric acid is too high, the magnetic powder will dissolve, which is inappropriate. The magnetic floc decomposed in such a short residence time is further transferred to the sedimentation tank 14.

  In the settling tank 14, oil having a low specific gravity (to-be-removed object) floats and is separated upward at an appropriate residence time, and a flocculant containing treated water and a magnetic powder having a large specific gravity are separated below the oil. . Since the raw water 1 is separated from the raw water 1 in this manner, the oil (to-be-removed object) 15 is recovered in the seawater containing crude oil, and the mixture 16 of the flocculant containing the seawater and the magnetic powder is returned to the raw water 1. Reused.

  However, when the mixture 16 of the flocculant containing seawater and the magnetic powder is reused in this way, suspended particles contained in the raw water (usually called SS (Suspended Solids)) increase in long-term continuous operation. As a result, the SS concentration in the mixture 16 of the coagulant and magnetic powder containing seawater increases and the SS concentration of the purified water 17 also increases.

Therefore, in the present invention, a bypass is provided in the piping line of the purified water (treated water) 17 and the turbidimeter 29 is provided in the bypass so that the SS concentration can be always measured. When the SS concentration of the purified water (treated water) 17 exceeds the reference SS concentration, a signal from the turbidimeter 29 opens the automatic valve 18 provided at the lower part of the settling tank 14 to suspend it outside the system. It has a control structure that can discharge particles (SS).
The blade 20 provided in the sludge decomposition tank 12 can be a general paddle blade, turbine blade, or the like. When the amount of processing is large, the blades may be multistaged.

  Therefore, according to the first embodiment, the magnetic floc 10 can be decomposed with hydrochloric acid and separated by sedimentation by the sludge recovery function comprising the sludge decomposition tank (second stirring tank) 12 and the settling tank 14. The flocculant and the magnetic powder can be recovered and reused, and stable purified water can be obtained even when the SS concentration is increased, so that the operation cost of the apparatus can be reduced. Furthermore, when the raw water contains valuable crude oil, the amount of recovered crude oil can be increased.

[Second Embodiment]
A second embodiment of the magnetic separation and purification apparatus according to the present invention will be described with reference to FIG. FIG. 2 shows the flow of the sludge recovery function in the second embodiment of the magnetic separation and purification apparatus. When ferric chloride is used as the flocculant, since ferric chloride is acidic, the pH of the agitation tank 3 and the agitation tank 4 increases with the passage of time for reuse, and the magnetic floc 10 is formed. Will be inhibited. In general floc aggregation methods, the pH is preferably in the range of 6-8.

  Therefore, in the second embodiment, a pH meter 22 is further provided in the stirring tank 3 or the stirring tank 4, and when the pH exceeds a set value, for example, sodium hydroxide 21 is automatically added to the stirring tank. 3 and 4 are configured to control the pH. That is, the second embodiment is different from the first embodiment in that, for example, sodium hydroxide 21 is automatically added to control the pH in the agitation tanks 3 and 4 and increase. It is in the point to prevent.

  Therefore, according to the second embodiment, the magnetic floc can be decomposed with hydrochloric acid and separated by settling, the flocculant and the magnetic powder can be recovered and reused, and the SS concentration and pH can be reduced. Since stable purified water can be obtained even when it rises, there is an effect that the operating cost of the apparatus can be reduced. Furthermore, when the raw water contains valuable crude oil, there is an effect that the amount of recovered crude oil can be increased.

[Third Embodiment]
A third embodiment of the magnetic separation and purification apparatus according to the present invention will be described with reference to FIG. FIG. 3 shows a flow of the sludge recovery function in the third embodiment of the magnetic separation and purification device. When long-term continuous operation is performed, suspended particles (usually called SS) contained in the raw water increase and accumulate in the sedimentation tank 14, and the SS concentration in the mixture 16 of the coagulant and magnetic powder containing seawater also increases. As a result, the SS concentration of the purified water 17 also increases. In the first and second embodiments, a bypass is provided in the piping line of the purified water 17 and the turbidimeter 29 is provided in the bypass so that the SS concentration can always be measured. Then, when the SS concentration of the purified water (treated water) 17 exceeds the reference SS concentration, the automatic valve 18 is opened by a signal from the turbidimeter 29 to discharge SS out of the system. However, at this time, the magnetic powder for forming the magnetic floc is partially discharged out of the system together with the SS, and the amount of the magnetic powder to be reused is reduced.

  Therefore, in the third embodiment, when the SS concentration further increases, first, the automatic valve 18 provided at the lower part of the sedimentation tank 14 is opened, and SS and magnetic powder are transferred to the magnetic powder recovery tank 30. Once stored, the magnetic powder is adsorbed by operating the electromagnet 31 installed around the magnetic powder recovery tank 30, and then the automatic valve 32 is opened to discharge only the SS component out of the system. Next, when the SS concentration is lowered, the automatic valve 18 and the automatic valve 32 are closed and the valve 33 is opened, and the liquid that partially bypasses the mixture 16 of the coagulant and magnetic powder containing seawater is recovered in the magnetic powder recovery tank. 30, the magnetic powder 35 in the magnetic powder recovery tank 30 is recovered and returned to the raw water 1. At this time, the electromagnet 31 is not operating. That is, in the third embodiment, the difference from the first and second embodiments is that when the SS concentration of the purified water 17 exceeds the reference SS concentration, only the SS portion from the settling tank 14 is obtained. They are discharged out of the system, and the magnetic powder is recovered and returned to the raw water 1 for reuse.

  Therefore, according to the third embodiment, the magnetic floc can be decomposed with hydrochloric acid and separated by sedimentation, the flocculant and the magnetic powder can be recovered and reused, and the SS concentration and pH can be reduced. Even when it rises, stable purified water can be obtained, and the amount of recovered magnetic powder can be increased, so that there is an effect that the operating cost of the apparatus can be reduced. Furthermore, when the raw water contains valuable crude oil, there is an effect that the amount of recovered crude oil can be increased.

  The present invention relates to a magnetic separation device for the purpose of water purification, particularly for easily decomposing sludge and recovering and reusing flocculant and magnetic powder, but for removing heavy metals in wastewater. Is also applicable.

It is the figure which showed the flow of the sludge collection | recovery function in 1st Embodiment of the magnetic separation purification apparatus which concerns on this invention. It is the figure which showed the flow of the sludge collection | recovery function in 2nd Embodiment of the magnetic separation purification apparatus which concerns on this invention. It is the figure which showed the flow of the sludge collection | recovery function in 3rd Embodiment of the magnetic separation purification apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Raw water (processed fluid), 2 ... Polymer flocculant, 3, 4 ... Stirring tank (1st stirring tank), 5 ... Filtration tank, 6 ... Rotating drum, 6 '... Net | network (filtration means), 7 DESCRIPTION OF SYMBOLS ... Rotating body, 8 ... Magnetic field generation means, 9 ... Scraping means, 10 ... Magnetic flock (aggregated substance), 11 ... Sludge collection tank, 12 ... Sludge decomposition tank (second stirring tank), 13 ... Hydrochloric acid, 14 ... Precipitation tank, 17 ... purified water (treated water), 18 ... automatic valve, 20 ... wing, 21 ... sodium hydroxide, 22 ... pH meter, 29 ... turbidity meter, 30 ... magnetic powder recovery tank, 31 ... electromagnet, 32 ... automatic valve, 33 ... valve, 35 ... magnetic powder.

Claims (4)

A first agitation tank for supplying a magnetic substance and a flocculant to a fluid to be treated containing the substance to be removed, and aggregating the substance to be removed into an agglomerated substance by the magnetic substance and the flocculant; A filtration tank that obtains treated water by filtering the fluid to be treated containing the aggregated substance introduced from one agitation tank through a filtration means having an opening through which the aggregated substance cannot pass; and the aggregated substance collected by the filtration means In a magnetic separation and purification device equipped with sludge recovery means for magnetically collecting and recovering
A second agitation tank for adding hydrochloric acid to the agglomerated material recovered by the sludge recovery means and agitating; and a precipitation tank for separating the agglomerated material decomposed by the hydrochloric acid into a magnetic substance, an aggregating agent, and an object to be removed. Magnetic separation and purification, wherein the magnetic substance and the flocculant separated by the settling tank are returned and added to the fluid to be treated supplied to the first stirring tank and reused apparatus.   A turbidimeter for measuring the suspended particle concentration in the treated water obtained by filtration from the filtration tank is provided, and when the suspended particle concentration measured by the turbidimeter exceeds a reference concentration, at least the suspension is suspended from the precipitation tank. 2. The magnetic separation and purification device according to claim 1, wherein the turbid particles are discharged out of the system.   A turbidimeter is provided to measure the concentration of suspended particles in the treated water obtained by filtration from the filtration tank. The particles are discharged out of the system, and the magnetic powder discharged together with the suspended particles is recovered in a magnetic powder recovery tank provided downstream of the settling tank and supplied to the first stirring tank. The magnetic separation and purification device according to claim 1, wherein the magnetic separation and purification device is configured to return to the treated fluid. 4. The magnetic separation and purification device according to claim 1, wherein a pH meter is provided in the first agitation tank, and the pH of the first agitation tank can be adjusted by an instruction from the pH meter.

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