JP2007083124A - Method and system for cleaning water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable excellent water cleaning treatment without using a large amount of flocculant to raw water increased with turbidity by the growth of algae. <P>SOLUTION: An electric potential state is generated which causes easy flocculation by carrying out a pre-treatment process in a raw water pond 10 and applying the raw water with magnetism by a magnetization device 1. In a next flock formation process, a state of easy flocculation and settledability of flocks is generated by loading the flocculant into water through the pre-treatment process, and then the flock is separated and settled in a flock settling process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water purification method and a water purification system for introducing and purifying raw water from water sources such as rivers and lakes.

  Conventionally, in water purification plants, surface water such as river water and lake water has been introduced as raw water as shown in FIG. 7. In order to reduce the turbidity of raw water, sulfuric acid bands and polyaluminum chloride (PAC) are added to the raw water. ) And the like are added and mixed by stirring to form a floc in which the suspension is agglomerated. Thereafter, flocs are solid-liquid separated in the coagulating sedimentation basin and settled. The floc is extracted from the coagulation sedimentation basin as sludge, and the supernatant water is led to the rapid filtration basin as treated water (see Patent Document 1). The details of the water purification system will be described later.

JP 2003-334562 A

  However, in recent years, eutrophication of rivers and lakes has progressed, and algae (blue sea cucumbers) have grown. Since algae has poor cohesiveness due to the flocculant, it is difficult to settle in the coagulation sedimentation basin, and it takes a long time to settle, and there is a problem that sludge that cannot be settled flows into the rapid filtration basin. On the other hand, when a large amount of a flocculant is added in order to accelerate the coagulation sedimentation, not only the running cost increases, but also there is a problem that the amount of sludge generated increases and the treatment load of sludge as industrial waste increases. .

  In addition, since a commonly used flocculant such as PAC is an acidic substance, if the amount added is large, the treated water becomes acidic and is not preferable, and is particularly inappropriate as drinking water.

  This invention has been made paying attention to the above-mentioned problems, and flocs that are likely to settle in a coagulation sedimentation basin without adding a large amount of coagulant to raw water that contains a large amount of algae such as blue seaweed. An object of the present invention is to provide a water purification treatment method and a water purification treatment system that can be sufficiently purified by forming.

  The water purification method according to the present invention is a method in which a floc is formed and precipitated by administering and stirring a flocculant to raw water to be purified, and then the supernatant water is derived, and magnetism is applied to the raw water. A pretreatment step for generating a state in which flocs are likely to be formed, a floc forming step for producing flocs in a precipitable state by administering a flocculant to water that has undergone the pretreatment step, and precipitating the flocs. A floc precipitation step for obtaining a supernatant water is sequentially performed.

According to the present invention, by applying magnetism to the raw water to be purified, the amount of oxygen taken into the water is increased and the function of purifying water by aeration is increased. In addition, a weak current flows in water due to Fleming's law. Due to the action of this weak current, the potential of suspended matter on the water surface or in the water is lowered. When the potential of the floating material is lowered, the repulsion between the floating materials is reduced, so that the floating materials are easily aggregated and a floc is easily formed.
In the next floc forming step, flocs are formed when a flocculant such as PAC is added to the water that has undergone the pretreatment step. When the floc becomes large and heavy, the floc is completely precipitated as sludge by solid-liquid separation. In this case, even a thing with poor cohesion like algae is easy to aggregate, and the generation of floc is promoted, so that the precipitation is accelerated. Thereby, good supernatant water can be obtained, and the purification function can be enhanced for raw water whose source is rivers and lakes where algae grow.

  Various methods are conceivable for magnetizing the raw water in the pretreatment step. In a preferred embodiment, the magnetizing apparatus is installed in a pond into which raw water is introduced, and purification treatment should be performed in the apparatus. By introducing raw water and passing it through a magnetic field, magnetism is applied to the raw water.

  Further, in a preferred embodiment of the present invention, the floc forming step includes a stirring step of stirring the water to which the flocculant is administered, and the dosage of the flocculant is set so that the floc does not precipitate during the stirring step. Is to adjust.

  By the way, when the raw water is magnetized, floc formation is promoted and floc sedimentation performance is enhanced. On the other hand, floc sedimentation rate is increased, and floc sedimentation may occur during the floc formation process. . The floc forming step usually includes a step of stirring water to which the flocculant is administered, and if the floc adheres to the stirring device that stirs water, it may cause a failure of the stirring device. Moreover, it is normal that the pond where the stirring process is carried out is not provided with equipment for removing the aggregated sediment, and it is expensive to install the equipment.

  According to this embodiment, the floc can be completely precipitated as sludge in the floc precipitation step without reducing the floc in the floc forming step by reducing the dose of the flocculant to the water by the water magnetization treatment. Thus, this can solve the above-mentioned problem of the stirrer failure and maintain an excellent purification function. Moreover, since the amount of sludge generation is reduced by reducing the dose of the flocculant, costs such as sludge treatment costs can be reduced.

  The water purification treatment system according to the present invention is to extract flocs by precipitating a flocculant by administering and stirring a flocculant to raw water to be purified, and then deriving the supernatant water from which raw water is introduced. A water pond, a mixing pond for administering a flocculant to water introduced from the raw water pond, a floc forming pond for agitating the water introduced from the mixing pond with a stirrer to form a floc, and precipitating the floc And a coagulation sedimentation basin for obtaining supernatant water. In the raw water pond, there is installed a magnetization processing device that applies magnetism to the raw water by introducing the raw water and passing it through the magnetic field. The mixing pond is provided with an input mechanism for administering the flocculant to the water filled in the mixing basin and an adjustment mechanism for adjusting the dose of the flocculant by the input mechanism.

In the above-described water purification system, when magnetism is applied to raw water taken from a water source by a magnetization processing device, a state in which flocs are easily formed is obtained.
Water that has been magnetized in the raw water pond is introduced into the mixing pond. In the mixing pond, the flocculant is administered by the charging mechanism. In the next floc formation pond, water is stirred by a stirrer to form a floc. In the mixing pond, the floc can be prevented from being precipitated in the floc-forming pond by adjusting the dosage of the flocculant by the adjusting mechanism.
Next, the floc is separated into solid and liquid in the coagulating sedimentation basin, and the floc settles as sludge, whereby a high quality supernatant water is obtained.

According to the present invention, by applying a magnetic force from the magnetic treatment device to the raw water, it is possible to increase the amount of oxygen taken into the water and improve the function of purifying water by aeration. It is possible to easily aggregate the objects and easily form a floc. As a result, an excellent purification function can be exhibited even for raw water containing pollutants with poor cohesive properties such as algae.
Furthermore, by adjusting the dosage of the flocculant, it is possible to optimally adjust the floc sedimentation time and the amount of sediment, and it is possible to reduce costs such as sludge treatment costs.

FIG. 1 shows a configuration of a water purification treatment method and a water purification treatment system according to an embodiment of the present invention.
The water purification system of the illustrated example is introduced from a raw water pond 10 for introducing raw water taken from a water source, a landing well 11 for administering a neutralizing agent, a mixing pond 12 for administering a flocculant to the raw water, and a mixing pond 12. It includes a floc formation pond 13 for agitating the produced water by the agitator 9 to form flocs, and an agglomeration sedimentation basin 14 for solid-liquid separation and precipitation of the flocs.

The raw water pond 10 is provided with a magnetization processing device 1 that applies magnetism to the raw water by introducing the raw water into the inside and passing it through the magnetic field.
This magnetization processing apparatus 1 generates a state in which flocs are likely to be formed in the subsequent flock formation step even for raw water containing algae or the like having poor aggregability due to the flocculant by performing magnetization treatment on the raw water. belongs to.

  As shown in FIG. 2, the magnetization processing apparatus 1 is installed in the raw water pond 10 in a submerged state, and is supported on a substrate P installed on the bottom surface f.

  The magnetization processing apparatus 1 includes a submersible pump 2, a flowing water pipe 3, an intake pipe 4, and a magnetization processing tool 5. The submersible pump 2 sucks water in the raw pond 10 from the suction port 20 and discharges it from the discharge port 21. The inflow pipe 3 is provided with an inlet 30 at one end and an outlet 31 at the other end. The inlet 30 is connected to the discharge port 21 of the submersible pump 2, and the outlet 31 opens into the raw water pond 10. is doing.

  An upward connecting portion 32 is formed in the water pipe 3 at a position close to the inlet 30. An opening at the lower end of the intake pipe 4 is connected to the connecting portion 32, and the intake pipe 4 communicates with the flow path of the flowing water pipe 3. The intake pipe 4 is formed in such a length that its upper end can protrude from the water surface. Since the opening at the lower end of the intake pipe 4 faces the flow path in the flowing water pipe 3 through the connecting portion 32 and the opening 41 at the outer periphery of the upper end is located on the water surface w, the water flow in the flowing water pipe 3 As a result, the pressure in the intake pipe 4 is reduced to a negative pressure, and air is introduced from the intake pipe 4 into the flowing water pipe 3.

  A tubular body 6 constituting the magnetization processing tool 5 is interposed in the middle of the flowing water pipe 3, and therefore, the flowing water pipe 3 is separated into an upstream pipe 3A and a downstream pipe 3B. As shown in FIG. 3, an outlet 60 of the tubular body 6 is connected to the outlet 33 of the upstream pipe 3A, and an outlet 61 of the tubular body 6 is connected to the inlet 34 of the downstream pipe 3B.

  3 includes a tubular body 6 having an inlet 60 at one end and an outlet 61 at the other end, and a plurality of magnetic field generators 7 attached to the tubular body 6. is there. The tubular body 6 has a magnetized region at the center of the length. As shown in FIG. 4, the tubular body 6 has a flat cross-sectional rectangular shape in which the longitudinal passage width y of the passage 63 is sufficiently larger than the lateral passage width x. It is formed into a shape. The side wall surfaces 62R and 62L of the tubular body 6 are opposed to each other with a narrow passage width x, and a plurality of magnetic field generators 7 are attached to the opposed side wall surfaces 62R and 62L.

  Each magnetic field generator 7 has a plurality of permanent magnets 71 loaded in a laminated state with the magnetic poles aligned in the case body 70, and each magnetic field generator 7 has different magnetic poles N and S facing each other. Are fixedly attached to the outer peripheral surface of the tubular body 6.

  In this embodiment, the magnetization processing tool 5 is disposed downstream of the communication position between the water flow pipe 3 and the intake pipe 4, but may be disposed upstream of the communication position of the water flow pipe 3 and the intake pipe 4. Good.

  Returning to FIG. 1, the charging well 11 is provided with a charging mechanism 16 for administering a neutralizing agent to raw water, and the mixing pond 12 is provided with a charging mechanism 17 for charging a flocculant into raw water. ing. The charging mechanisms 16 and 17 are provided with adjusting mechanisms 18 and 19 for adjusting the doses of the neutralizing agent and the flocculant, respectively.

  An inorganic flocculant such as PAC or sulfuric acid band is used as the flocculant. Since PAC and sulfate bands are acidic substances, a neutralizing agent is administered in the landing well 11 in order to neutralize the water to which the flocculant has been administered. A strong alkaline substance such as caustic soda is used as the neutralizing agent.

The neutralizing agent charging mechanism 16 has a tank 16C in which a neutralizing agent is charged, and has a charging port 16B opened below the tank 16C. The charging port 16B is provided with a solenoid valve 16A. When the solenoid valve 16A is opened, a neutralizing agent is administered to the landing well 11 from the charging port 16B.
The flocculant charging mechanism 17 has the same configuration, and has a tank 17C in which the flocculant is loaded, and has a charging port 17B opened below the tank 17C. The charging port 17B is provided with an electromagnetic valve 17A. When the electromagnetic valve 17A is opened, the flocculant is administered to the mixing basin 12 from the charging port 17B.

The solenoid valves 16A and 17A are controlled to be opened and closed by the control device 8. The solenoid valve 16A and the control device 8 constitute a neutralizing agent adjusting mechanism 18, and the solenoid valve 17A and the control device 8 agglomerate. An agent adjustment mechanism 19 is configured.
The control device 8 is composed of a programmed computer, and opens and closes the electromagnetic valves 16A and 17A by sending drive signals s1 and s2 having a predetermined pulse width to the electromagnetic valves 16A and 17A in a predetermined cycle. Control. In this embodiment, each electromagnetic valve 16A, 17A is opened at a specific cycle, and the opening time of each electromagnetic valve 16A, 17A is adjusted to adjust the amount of the neutralizing agent or the flocculant. .
The control device 8 can be realized not only by a computer but also by a dedicated hardware circuit.

  Next, the operation of the above-described water purification system will be described. When the submersible pump 2 of the magnetization processing apparatus 1 is driven in the raw water pond 10, the raw water in the raw water pond 10 sucked from the suction port 20 of the submersible pump 2 passes from the discharge port 21 of the submersible pump 2 to the inlet 30 of the water pipe 3. It is sent. The raw water fed into the water flow pipe 3 flows through the flow path in the flow water pipe 3 and flows out from the outlet 31 into the raw water basin 10, but the air introduced into the flow water pipe 3 from the intake pipe 4 in the middle of the flow path. Becomes bubbles and enters the water stream. As a result, it is injected as a gas-liquid mixed flow from the outlet 31 into the pond, whereby stirring and aeration are performed.

  The raw water flowing through the water flow pipe 3 is magnetized by the magnetizing tool 5. When water is magnetized by the action of a magnetic field, the amount of oxygen taken into the water is increased and the function of purifying water by aeration is increased. Further, a weak current flows in the water according to Fleming's law, and the potential of floating substances on the water surface w or in the water is lowered by the action of the weak current. When the potential of the suspended matter is lowered, the repulsive force between the suspended matter is reduced, the aggregation of the suspended matter is promoted, and a floc is easily formed.

  The raw water that has been magnetized in the raw water pond 10 is introduced into the landing well 11 and administered with a neutralizing agent. Next, the flocculant is administered to the mixing basin 12. The water to which the flocculant has been administered is sent from the mixing basin 12 to the floc forming pond 13 where the flocs are formed by stirring with the stirring device 9.

FIG. 5 shows the case where the same amount of neutralizing agent and flocculant as in the conventional case is administered to the raw water. Precipitation of floc F occurs in the floc-forming pond 13. If sedimentation of floc F occurs from the floc formation pond 13, sludge adheres to the stirring device 9 and causes a failure. Further, the floc formation pond 13 is not provided with equipment for removing the aggregated precipitate, and the aggregated precipitate cannot be recovered.
FIG. 6 shows a case where the amounts of the neutralizing agent and the flocculant administered to the raw water are adjusted to half of the conventional amount. Since the raw water is magnetized, even if the doses of the neutralizing agent and the flocculant are halved compared to the conventional water, the flocculent sedimentation performance does not change and floc F is formed and precipitates. In this case, the floc F is settled in the coagulation sedimentation basin 14 without being precipitated in the floc formation basin 13, and the cost is reduced by halving the dose of the coagulant and the neutralizing agent and the amount of sludge sedimentation is reduced. Reduction of sludge treatment costs can be realized.

  The floc F separated by solid-liquid separation in the coagulation sedimentation tank 14 is extracted as sludge, and high-quality supernatant water is sent to the rapid filtration basin 15.

It is explanatory drawing which shows the water purification system which concerns on this invention. It is a side view of a magnetization processing apparatus. It is a side view of a magnetization processing tool. It is sectional drawing which follows the AA line of FIG. It is explanatory drawing which shows the precipitation state of the floc when the same amount of flocculants as usual is thrown into raw | natural water. It is explanatory drawing which shows A the precipitation state of the floc when the injection | throwing-in amount of a flocculent is made into the half of the past. It is explanatory drawing which shows the conventional water purification system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetization processing apparatus 8 Control apparatus 9 Stirring apparatus 10 Raw water pond 12 Mixing pond 13 Flock formation pond 14 Coagulation sedimentation basin 16,17 Feeding mechanism 18,19 Adjustment mechanism

Claims (4)

  In the water purification method in which flocs are formed and precipitated by administering and aggregating the flocculant to the raw water to be purified, and then the supernatant water is derived, in a state in which flocs are easily formed by applying magnetism to the raw water A floc forming step for producing a floc in a state capable of being precipitated by administering a flocculant to the water that has undergone the pretreatment step, and a floc precipitation step for precipitating the floc to obtain a supernatant water A water purification method characterized by sequentially carrying out.   The pretreatment step is to install a magnetic treatment device in a pond into which raw water is introduced, introduce the raw water into the magnetization treatment device, and allow the raw water to pass through a magnetic field, thereby causing magnetism to act on the raw water. 1. The water purification method described in 1.   The floc forming step includes a stirring step of stirring water to which the flocculant is administered, and the dosage of the flocculant is adjusted so that the floc does not precipitate during the stirring step. Water purification method.   The raw water to be purified is administered by aggregating and stirring to form a floc, which is then precipitated, and then introduced into the raw water pond to introduce the raw water and the raw water pond in the purified water treatment system for deriving the supernatant water. A mixing pond for administering a flocculant to water, a floc-forming pond for stirring water introduced from the mixing pond with a stirrer to form a floc, and a coagulating sedimentation basin for precipitating the floc to obtain supernatant water In the raw water pond, a magnetic treatment device is installed that applies magnetic force to the raw water by introducing the raw water and passing it through the magnetic field, and the mixing pond is agglomerated into the water filled in the mixing pond. A water purification system in which an input mechanism for administering an agent and an adjustment mechanism for adjusting the dose of the flocculant by the input mechanism are provided.

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