JP2001327981A - Method and apparatus for treating metal-containing wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for treating metal-containing wastewater, capable of efficiently flocculating and sedimenting the metal components from wastewater containing metals and metal ions by synergistic effect of oxidizing precipitation and neutralizing sedimentation to certainly remove the same at a low cost. SOLUTION: The pH of wastewater supplied to a neutralizing and stirring tank 11 is adjusted to a proper range and an oxidizing agent is injected in wastewater under stirring to efficiently advance the oxidation of metal ions in wastewater by the oxidizing agent regardless of the pH state of wastewater to accelerate the oxidizing precipitation of metal ions and metal ions in wastewater are certainly precipitated in combination with neutralizing precipitation. Since a polymeric flocculant is injected in wastewater under stirring in a flocculation tank 30 to flocculate the metal component in wastewater, floes 43 are grown to be made easy to sediment and, in addition, the rising of floes 43 accompanied by the rising of wastewater is suppressed by the inclined plate 41 in a sedimentation tank 40 and the floes 43 after flocculation can be certainly separated and removed from wastewater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal-containing wastewater treatment method for purifying wastewater by separating and removing metals and metal ions from wastewater containing metals and metal ions, and a metal-containing wastewater treatment apparatus using the method. .

[0002]

2. Description of the Related Art In metalworking plants such as ironworks and plating plants, wastewater containing metals and metal ions is generated in the working process, but such wastewater cannot be discharged to the outside as it is, so that a predetermined purification treatment is required. was there. As a conventional metal-containing wastewater treatment method for performing such a purification treatment, there is, for example, a method disclosed in Japanese Patent Publication No. 55-33954.

[0003] The above-mentioned conventional metal-containing wastewater treatment method comprises:
To a wastewater containing metal ions, a tannin extract having a purity of 60% or more and a solubility in water of 95% or more is added at a rate of 50 to 2500 g per 1 gram equivalent of metal. Or 13 p
The mixture is aged after stirring under H conditions, and if necessary, a coagulant is further added and mixed to separate metals.

Another conventional method for treating metal-containing wastewater is disclosed in Japanese Patent Publication No. 63-2677. This other conventional metal-containing wastewater treatment method comprises adding a viscose rayon plant wastewater to a non-slurry wastewater containing a heavy metal and an alkaline earth metal in such an amount that the pH of the wastewater exceeds 10 to 13 or less. , Heavy metals and alkaline earth metals are insolubilized, and the insolubilized heavy metals and alkaline earth metals are separated from wastewater.

[0005]

Since the conventional method for treating metal-containing waste water is constituted as described above, in the former case, a large amount of tannin, which is 50 to 2500 times the amount of metal to be removed, is used. There is a problem that the addition of the extract is necessary, and the mechanism of the processing apparatus is enlarged, and the processing cost is also increased.

[0006] On the other hand, in the latter case, the viscose rayon factory waste liquid is generated only in a limited place such as the factory, and the metalworking of an iron mill or a plating factory, etc., which has a small relationship with the viscose rayon factory. There was a problem that it could not be widely and generally applied, such as being difficult to obtain in factories. The present invention has been made in order to solve the above-mentioned problems, and a metal component from wastewater containing metal and metal ions is efficiently coagulated and precipitated by a synergistic effect of oxidative precipitation and neutralization precipitation (co-precipitation effect), and low It is an object of the present invention to provide a metal-containing wastewater treatment method capable of reliably performing a removal treatment at a low cost and an apparatus using the method.

[0007]

The metal-containing wastewater treatment method according to the present invention is a metal-containing wastewater treatment method for removing at least metal and metal ions from wastewater containing predetermined metals and / or metal ions. Given p
An H adjuster is injected to adjust the pH of the wastewater within a preset range, a predetermined oxidant is injected from the oxidizer injector into the wastewater after the pH adjustment, and the mixture is stirred to remove metal ions in the wastewater. It is oxidized to precipitate as metal and / or metal compound, the wastewater in the deposited state is flowed into a predetermined flocculation tank, a predetermined flocculant is injected into the wastewater and stirred, and the metal component is flocculated as floc. The floc coagulated wastewater is allowed to flow into a predetermined sedimentation tank adjacent to the coagulation tank, and the drainage is passed from below to above between a plurality of substantially plate-like bodies that are arranged in a tilted state at predetermined intervals in the sedimentation tank. The floc in the wastewater is separated from the wastewater by the substantially plate-like body, and the supernatant of the wastewater is obtained in the upper part of the settling tank.

As described above, in the present invention, the pH of wastewater containing metal and metal ions is adjusted, an oxidizing agent is injected and stirred, and metal ions in the wastewater are oxidized and precipitated as metal components. By removing everything, the wastewater can be adjusted to an appropriate pH irrespective of the pH of the wastewater, and the oxidant can be quickly and uniformly mixed with the wastewater by stirring. Thus, the metal ions can be efficiently oxidized, and the metal ions can be oxidized and deposited reliably. In addition, by injecting a flocculant into the wastewater that has flowed into the flocculation tank and further stirring, the flocs in which the metals and metal compounds contained in the wastewater are flocculated are coarsened, making the flocs less likely to break and sedimentation easier. Separation from wastewater becomes easy. Furthermore, a plurality of inclined plate-like bodies are disposed in the sedimentation tank, and the substantially plate-like body rises in floc as the drainage rises with respect to drainage flowing upward from below between the plate-like bodies. By suppressing the flocculation, flocs after coagulation can be surely separated and removed from the wastewater, and finally the wastewater can be brought into a clean supernatant state, and can be discharged to the outside without any problem.

In the method for treating metal-containing wastewater according to the present invention, the wastewater after the injection of the oxidizing agent is allowed to flow into a predetermined oxidation tank as required, and a predetermined aeration is performed on the wastewater in the oxidation tank. After air is blown in using an apparatus to oxidize metal ions in the wastewater with air, the wastewater is allowed to flow into the coagulation tank. As described above, in the present invention, the aeration device blows air into the wastewater that has flowed into the oxidation tank, and causes metal ions to undergo air oxidation with the contact between the wastewater and the air. Oxidation and air oxidation can simultaneously proceed to promote the oxidative precipitation of metal ions, and together with the neutralization precipitation accompanying the injection of the pH adjuster, ensure that the metal ions in the wastewater are metal and / or metal compounds. And can be removed by precipitation.

In the method for treating a metal-containing wastewater according to the present invention, the supernatant of the wastewater in the sedimentation tank is allowed to flow into a predetermined discharge tank, if necessary, and a predetermined flow rate monitoring device determines that the wastewater has an upper limit of the discharge tank. When the water level is reached, the discharge valve of the discharge tank is opened to discharge the drainage to the outside, and when the drainage reaches the lower limit of the discharge tank, the discharge valve is closed, while the drainage decreases from the lower limit. The time required to reach the upper limit water level is measured to monitor the state of drainage flowing into the discharge tank. As described above, in the present invention, the discharge monitoring tank detects the upper limit water level and the lower limit water level of the discharge tank, controls the discharge valve, and controls the discharge valve for the discharge tank storing the wastewater from the sedimentation tank. By measuring the time from when the water reaches the upper limit water level, the time required to reach the upper limit water level from the lower water level is compared with a preset reference time, and the water distribution pipes in each part of the treatment equipment are blocked and the intake pump is clogged. Such as, it is possible to detect an abnormal state where the inflow of drainage into the discharge tank is delayed from an increase in the required time with respect to a reference time,
The same level of reliability as regular monitoring in each processing stage can be obtained. Also, the total amount of treated water can be automatically measured by the flow monitoring device, and the amount of treated water can be measured without installing a flow meter.

In the method for treating metal-containing wastewater according to the present invention, the wastewater is floated on the water surface by a scum stopper provided in the middle of a flow path from the sedimentation tank to the discharge tank as necessary. Foreign substances are separated from the supernatant of the wastewater. As described above, in the present invention, the scum stopper provided in the middle of the flow path from the sedimentation tank to the discharge tank hinders the movement of foreign matters floating on the water surface of the wastewater to the subsequent stage, and the foreign matter on the drainage water surface is also reliably drained. By separating from
Only the clean supernatant from the sedimentation tank is allowed to flow into the discharge tank at the subsequent stage, which can be discharged to the outside without any problems. Also, the wastewater can be reused, and the discharge path from the discharge tank to the outside is blocked by foreign substances. Can also be prevented.

In addition, the metal-containing wastewater treatment method according to the present invention may be configured such that the amount of oxidant injected from the oxidant injector is determined based on the result of monitoring the state of inflow of wastewater into the discharge tank by the flow monitoring device, if necessary. Is controlled. As described above, in the present invention, in accordance with a change in the state of inflow of wastewater into the discharge tank monitored by the flow rate monitoring device, the amount of oxidant injected into the oxidant injector is controlled to reach the upper limit level from the lower limit level. By limiting the amount of oxidant injected for abnormal conditions where the required time is longer than the reference time, it is possible to prevent the oxidant from becoming too concentrated in wastewater that has been stuck in abnormal conditions,
It is possible to prevent wasteful consumption of the oxidizing agent and generation of toxic gas due to the reaction between the concentrated oxidizing agent and the wastewater.

Further, the method for treating metal-containing wastewater according to the present invention, if necessary, is based on the result of monitoring the state of inflow of wastewater into the discharge tank by the flow rate monitoring device, and the amount of coagulant injected from the coagulant injection device. Is controlled. As described above, in the present invention, in accordance with a change in the state of inflow of drainage water into the discharge tank monitored by the flow rate monitoring device, the injection amount of the coagulant into the coagulant injection device is controlled to reach the upper limit water level from the lower limit water level. By limiting the coagulant injection amount to abnormal conditions where the required time is longer than the reference time, it is possible to prevent the flocculant from becoming excessively concentrated in wastewater that has been stagnated in abnormal conditions,
It is possible to prevent unnecessary consumption of the coagulant.

Further, the metal-containing wastewater treatment apparatus according to the present invention is characterized in that a neutralization stirring tank to which the wastewater is supplied and a predetermined pH adjuster are injected into the wastewater in the neutralization stirring tank to reduce the pH of the wastewater.
A pH adjusting device for adjusting H within a preset range; an oxidizing agent injecting device for injecting a predetermined oxidizing agent into the pH-adjusted wastewater in the neutralization stirring tank; A first stirring device that stirs the wastewater together with a pH adjuster and an oxidizing agent, a predetermined flocculation tank into which the stirred wastewater flows, and a predetermined amount of a flocculant injected into the wastewater in the flocculation tank. A coagulant injection device, a second stirrer disposed in the coagulation tank and stirring the wastewater together with the coagulant, and a coagulation tank disposed in connection with the coagulation tank to flow the wastewater stirred from the coagulation tank. A predetermined sedimentation tank and a plurality of substantially plate-like bodies arranged in a tilted state at predetermined intervals in the sedimentation tank, and are aggregated in drainage passed from below to above between the substantially plate-like bodies. Separated from the wastewater, the flocs of metal Clear, and go is intended and a tilt plate to the accumulated state.

As described above, in the present invention, the pH adjusting device is provided in combination with the neutralization stirring tank, the oxidizing agent injection device and the first stirring device are provided, and the mixture is charged into the neutralization stirring tank. By adjusting the pH of the wastewater and injecting and stirring an oxidizing agent to oxidize metal ions in the wastewater, the wastewater can be adjusted to an appropriate pH regardless of the state of the pH of the wastewater. And, the oxidizing agent can be quickly and uniformly mixed into the wastewater by stirring of the first stirring device,
The metal ions can be efficiently oxidized by the oxidizing agent, and the metal ions can be reliably oxidized and deposited. Also, the flocculant is injected from the flocculant injection device into the wastewater flowing into the flocculation tank, and further stirred by the second stirring device, whereby the flocs in which the metals and metal compounds contained in the wastewater are aggregated are coarsened. And sedimentation are facilitated, and separation from wastewater is facilitated. Furthermore, a plurality of inclined plates are arranged in the sedimentation tank, and for the drainage that goes up from below between the inclined plates, the inclined plates suppress the rise of the flocs due to the rise of the drainage, thereby reducing the flocs after aggregation. The wastewater can be surely separated and removed, and finally the wastewater can be brought into a clean supernatant state, so that discharge to the outside can be performed without any problem.

The metal-containing wastewater treatment apparatus according to the present invention is provided, if necessary, in front of the agglomeration tank, and is provided with a predetermined oxidation tank into which an oxidizing agent is injected and into which agitated wastewater flows. A predetermined aeration device for blowing air into the wastewater in the oxidation tank to perform air oxidation of metal ions in the wastewater,
The wastewater flows into the coagulation tank from the oxidation tank. As described above, in the present invention, an oxidation tank is provided in a stage preceding the coagulation tank, and an aeration device is provided in the oxidation tank.
Air is blown into the wastewater in the oxidation tank, and air oxidation is caused to the metal ions by the contact between the wastewater and the air. Can promote oxidative precipitation,
Together with the neutralization precipitation accompanying the injection of the pH adjuster, metal ions in the wastewater can be reliably precipitated and removed as a metal and / or a metal compound.

In addition, the metal-containing wastewater treatment apparatus according to the present invention includes, as necessary, a predetermined discharge tank into which the supernatant of the wastewater in the settling tank flows, and which discharges the supernatant to the outside as necessary.
When the drainage reaches the upper limit water level of the discharge tank, the discharge valve of the discharge tank is opened to discharge the drainage to the outside, and when the drainage reaches the lower limit water level of the discharge tank, the discharge valve is opened. On the other hand, it is provided with a predetermined flow rate monitoring device that measures the time required for the waste water to reach the upper limit water level from the lower limit water level and monitors the state of the waste water flowing into the discharge tank. Thus, in the present invention, while providing a discharge tank for flowing wastewater from the sedimentation tank, and controlling the discharge valve of the discharge tank,
In addition, a flow rate monitoring device that monitors the state of inflow of wastewater into the discharge tank is provided, and the upper and lower water levels of the discharge tank are detected, the discharge valve is opened and closed, and the lower water level of the wastewater is changed from the lower water level to the upper water level. By measuring the time required to reach the required time, the required time is compared with a preset reference time, and abnormalities such as blockage of water distribution pipes in processing equipment and clogging of intake pumps, etc., that cause inflow of drainage to the discharge tank are delayed. The state can be detected from the increase of the required time with respect to the reference time, and the same reliability as that of the regular monitoring in each processing stage can be obtained. Also, the discharge flow rate can be grasped by counting the number of opening and closing of the discharge valve by the flow rate monitoring device, the total treated water amount can be automatically measured, and the treated water amount can be measured without installing a flow meter.

The metal-containing wastewater treatment apparatus according to the present invention is disposed, if necessary, in the middle of the flow path from the sedimentation tank of the supernatant of the wastewater to the discharge tank to drain foreign substances floating on the water surface. And a scum stopper for separating from the supernatant. As described above, in the present invention, the scum stopper is provided in the middle of the flow path from the sedimentation tank to the discharge tank, and the scum stopper prevents the foreign matter floating on the water surface from moving to the subsequent stage, and the scum stopper prevents the foreign matter from floating on the water surface. Foreign matter is surely separated from the wastewater, so that only the clean supernatant from the sedimentation tank is allowed to flow into the subsequent discharge tank, which can be discharged to the outside without any problems, and the wastewater can be reused and discharged. It is also possible to prevent the discharge path from the tank to the outside from being clogged by foreign matter.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal-containing wastewater treatment apparatus according to one embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of a metal-containing wastewater treatment device according to the present embodiment, FIG. 2 is a plan view of the metal-containing wastewater treatment device according to the present embodiment, and FIG. 3 is a metal-containing wastewater treatment according to the present embodiment. It is a block diagram of a processing device.

As shown in each of the drawings, the metal-containing wastewater treatment apparatus 1 according to the present embodiment is configured such that wastewater containing metal and / or metal ions is supplied from the outside at a predetermined flow rate by a water intake pump 110, and the pH of the wastewater is adjusted. A neutralization / stirring tank 10 in which adjustment and oxidant injection are performed, an effluent from the neutralizing / stirring tank 10, an oxidizing tank 20 for promoting oxidation of metal ions in the effluent, and a effluent from the oxidizing tank 20 A flocculation tank 30 which flocculates the metal component in the wastewater to form a floc;
A sedimentation tank 40 which is disposed in connection with the coagulation tank 30 to allow drainage to flow from the coagulation tank 30 and settle the flocs;
And a discharge tank 50 into which wastewater excluding flocs is introduced from the sedimentation tank 40 and discharged to the outside as necessary.

The neutralization and stirring tank 10 is formed as a section of a corner in the processing tank main body 100, which is a predetermined substantially box-shaped container, and is separated from other parts in the processing tank main body 100.
The oxidation tank 20 is configured to communicate with a part of the lower part. In combination with this neutralization stirring tank 10, the neutralization stirring tank 10
A predetermined pH adjuster (acidic agent such as sulfuric acid,
A pH adjuster 11 for injecting an alkaline agent such as sodium hydroxide) to adjust the pH of the wastewater within a preset range (a range of 7.5 to 8.6); And an oxidizing agent injection device 12 for injecting an oxidizing agent at a predetermined rate set in advance.
Further, in the neutralization stirring tank 10, a first stirring device 13 that stirs the wastewater together with the pH adjusting agent and the oxidizing agent and uniformly mixes the wastewater with the pH adjusting agent and the oxidizing agent is provided.

The oxidizing tank 20 is formed in the processing tank main body 100 as a section adjacent to the neutralizing and stirring tank 10. This is a configuration in which each of the corners of the tank main body 100 communicates with the current transformer tank 70 which forms a section at another corner. An aeration device 21 for blowing air into the wastewater in the oxidation tank 20 to oxidize metal ions in the wastewater with air is provided in the oxidation tank 20, and the metal ions in the wastewater are oxidized in air by aeration. It is a mechanism that promotes the oxidation of metal ions together with the oxidation by the agent.

The coagulation tank 30 is formed as a section at a corner opposite to the neutralization and stirring tank 10 in the processing tank main body 100, and communicates with the oxidation tank 20 via the current change tank 70. , And is configured to communicate with the sedimentation tank 40 via a predetermined rectification tank 80. In combination with the coagulation tank 30, a coagulant injection device 31 for injecting the polymer coagulant into the wastewater in the coagulation tank 30 at a predetermined ratio set in advance is used. In the coagulation tank 30, a second stirring device 3 for stirring the wastewater in the coagulation tank 30 together with the injected coagulant.
2 are provided. The second stirring device 32 performs a stirring operation on the wastewater into which the polymer flocculant has been injected, and coarsens the flocs 43 in which the metal and the metal compound are flocculated. The wastewater containing the flocs 43 flows from the lower part of the coagulation tank 30 to the rectification tank 8.
After moving to 0 and rising inside the straightening tank 80, the drainage water
The mechanism moves to the portion near the sedimentation tank 40 beyond the partition plate 80a in the inside of 0, and further descends to the sedimentation tank 40.

The sedimentation tank 40 is formed in the treatment tank main body 100 as a section adjacent to the coagulation tank 30 with the rectification tank 80 interposed therebetween, and is configured to communicate with the rectification tank 80 at a predetermined lower portion. The lower part in the sedimentation tank 40 is composed of a plurality of substantially plate-like bodies arranged at a predetermined interval in an inclined state. The inclined plate 41 for separating the flock 43 from the drainage is provided. Further, a scum stopper 42 for separating foreign substances 44 floating on the water surface of the wastewater from the wastewater is provided above the sedimentation tank 40. Further, at the bottom of the settling tank 40,
A sludge discharge valve 45 for discharging sludge (flock 43) accumulated at the bottom of the settling tank 40 is provided.

The discharge tank 50 is formed in the treatment tank main body 100 as a corner section adjacent to the neutralization stirring tank 10 and adjacent to the settling tank 40, and has an upper end of a partition part from the settling tank 40. In this configuration, excess wastewater is allowed to flow in, temporarily stored, and then discharged to the outside. In combination with this discharge tank 50, a water level sensor 51 for detecting the water level of the drainage in the discharge tank 50, and a discharge valve 52 for switching the discharge state and the storage state by opening and closing to adjust the amount of water in the discharge tank 50 are provided. It is a configuration provided. In addition, the water level sensor 5
A flow monitoring device 60 for controlling the opening and closing of the discharge valve 52 based on the detection information of No. 1 is separately provided.
Accordingly, control is performed such that when the water level sensor 51 detects the upper limit water level, the discharge valve 52 is opened, and when the water level sensor 51 detects the lower limit water level, the discharge valve 52 is closed. The flow monitoring device 60 counts the number of times the discharge valve 52 is opened and closed, and automatically uses the number of times of opening and closing and the known amount of stored water from the lower limit water level to the upper limit water level of the discharge tank 50 to automatically calculate the total treated water amount. It also has a measuring mechanism, and can measure the amount of treated water without installing a flow meter.

The flow rate monitoring device 60 is a control unit for automatic operation of the entire processing apparatus, and includes a water intake pump 110, an oxidizing agent injecting device 12, a first stirring device 13, an aeration device 21, a flocculant injecting device 31, Double stirring device 32 and sedimentation tank 40
It is also used for each control. The flow rate monitoring device 60 measures a required time from when the water level sensor 51 detects the lower limit water level to when it detects the upper limit water level, and compares the measured time with a predetermined reference time set in advance (corresponding to the required time in a steady state). By performing the comparison, the obstruction state of each water distribution pipes upstream of the discharge tank 50 and the abnormal operation state of the water intake pump 110 are monitored, and in the case of an abnormality such as the required time being about twice as long as the reference time, This is a mechanism that can perform stop control of all devices.

However, immediately after the operation of the processing apparatus is started, or when the sludge accumulated at the bottom of the settling tank 40 is discharged, the required time is lengthened in spite of normal operation. The time required for the drainage to sufficiently fill the tank 40 is subtracted from the required time, and then compared with the reference time. After each of the above states, the discharge tank 50
When the water level sensor 51 reaches the upper limit water level, it is determined that the entire treatment apparatus has sufficient drainage, and the required time is compared with the reference time as it is in a steady state.

Further, in the pH adjusting device 11, based on the detection of the pH sensor 11a disposed at a predetermined position in the neutralization stirring tank 10, a pH adjusting agent is appropriately injected into the waste water in the neutralization stirring tank 10, Although the pH of the wastewater is adjusted within an appropriate range, if the pH of the wastewater exceeds the appropriate range for a predetermined time, abnormality information is sent from the pH adjustment device 11 to the flow monitoring device 60, and the flow rate is adjusted. The monitoring device 60 controls the entire device to stop. In particular, when a chlorine agent is used as the oxidizing agent, when the pH of the wastewater falls out of the appropriate range to the acidic side and falls below a predetermined value, in order to prevent the generation of toxic chlorine gas, the flow rate is monitored as described above. The abnormality information is sent to the device 60, and the flow monitoring device 60 stops the oxidant injection by the oxidant injection device 12.

On the other hand, when the amount of water withdrawn from the settling tank 40 based on the operation time of the water intake pump 110 reaches a predetermined amount, the flow monitoring device 60 sets the sludge discharge valve 45 at the bottom of the settling tank 40 to a predetermined position. It is opened for a predetermined time, and the sludge accumulated at the bottom of the sedimentation tank 40 is discharged. In addition, when no change is detected in the water level detected by the water level sensor 51 when the discharge valve 52 is opened, the flow monitoring device 60 determines that the discharge is abnormal and stops the entire device. Then, when performing the above-described stop control, etc., the flow rate monitoring device 6 is simultaneously operated.
Reference numeral 0 denotes a mechanism for operating an alarm output unit such as a buzzer or a lamp to notify an administrator of an abnormal state.

Next, the processing operation of the metal-containing wastewater treatment apparatus based on the above configuration will be described. First, the neutralization stirring tank 1
With respect to 0, wastewater containing a predetermined metal and / or metal ion is supplied from the outside by the water intake pump 110. The pH adjusting device 11 controls the pH of the wastewater in the neutralization stirring tank 10.
Depending on the pH of the wastewater detected by the sensor 11a,
An acid agent or an alkaline agent as a regulator is injected in an amount corresponding to the detected pH value to adjust the pH of the wastewater to a preset range.

At the same time, the wastewater in the neutralization stirring tank 10
A predetermined oxidizing agent is injected from the oxidizing agent injection device 12, and the first stirring device 13 stirs the wastewater together with the pH adjusting agent and the oxidizing agent, uniformly mixes the wastewater with the pH adjusting agent and the oxidizing agent, and The metal ions are oxidized and precipitated as a metal and / or a metal compound. The stirred wastewater flows from the lower part of the neutralization stirring tank 10 to the adjacent oxidation tank 20.

In the oxidation tank 20, the wastewater is aerated with an aeration device 2.
1 is used to inject air to perform air oxidation of metal ions in wastewater. The wastewater that has been sufficiently blown with air is in oxidation tank 2
From the lower part 0, it flows into the coagulation tank 30 through the current change tank 70.
The polymer flocculant is injected from the coagulant injecting device 31 into the wastewater that has flowed into the coagulating tank 30, and is stirred by the second stirring device 32, so that the metal component is coagulated as flocs 43. The wastewater in the flocculated state is transferred to the flocculation tank 30.
It enters the rectification tank 80 from the lower part, and the coagulation tank 30 in the rectification tank 80.
After once ascending the deviating portion, the portion descends toward the sedimentation tank 40 in the rectification tank 80 beyond the partition plate 80a, and flows into the adjacent sedimentation tank 40 from the lower part of the rectification tank 80. Since the wastewater flowing out of the flocculation tank 30 is rectified by the rectification tank 80, the pulsation of the flow of the wastewater generated by the stirring operation of the second stirring device 32 is not transmitted to the precipitation tank 40, and the floc in the precipitation tank 40. 43 is promoted.

In the sedimentation tank 40, the inflowing waste water is transferred to the sedimentation tank 4.
A plurality of inclined plates 4 arranged at a predetermined interval in an inclined state within 0
1 when passing from the bottom to the top, the flocs 43 in the drainage are restrained from rising by the inclined plate and separated from the drainage, and the sedimentation tank 40
At the top, the supernatant of the drainage is obtained. The separated flocks 43 settle downward from the inclined plate 41 and settle in the sedimentation tank 4.
It accumulates at the bottom and is discharged outside if necessary. The supernatant of the wastewater in the sedimentation tank 40 flows into the discharge tank 50 beyond the partition between the sedimentation tank 40 and the discharge tank 50, and the scum stopper 42 provided immediately before this partition.
Accordingly, the foreign matter 44 floating on the water surface is also surely separated from the wastewater and removed, and only the clean wastewater flows into the discharge tank 50.

In the discharge tank 50, a water level sensor 51 detects the water level of the incoming waste water, and when the waste water reaches the upper limit water level of the discharge tank 50, the discharge valve 52 is opened under the control of the flow rate monitoring device 60. Discharge wastewater to the outside. When the wastewater reaches the lower limit water level of the discharge tank 50 due to the discharge, the discharge valve 52 is closed under the control of the flow monitoring device 60, and the discharge is interrupted. These are repeated while the drainage flows into the discharge tank 50. On the other hand, the flow monitoring device 60 measures the time until the wastewater reaches the upper limit water level from the lower limit water level of the discharge tank 50, monitors the state of the wastewater flowing into the discharge tank 50, and controls each part of the processing device as necessary. .

As described above, in the metal-containing wastewater treatment apparatus according to the present embodiment, the pH of the wastewater supplied to the neutralization and stirring tank 11 is adjusted to an appropriate range, and an oxidizing agent is injected and stirred. Subsequently, the oxidation tank 20 at the subsequent stage of the neutralization stirring tank 11
The air is blown into the wastewater inside, and the metal ions in the wastewater are oxidized by air. Therefore, regardless of the state of the pH of the wastewater, the wastewater is adjusted to an appropriate pH and then oxidized. The oxidation by the action of the agent and the air oxidation can proceed simultaneously to promote the oxidative precipitation of metal ions,
In combination with the neutralization precipitation accompanying the injection of the pH adjuster, metal ions in the wastewater can be reliably precipitated as metal and / or metal compound. In addition, since the polymer flocculant is injected into the wastewater flowing into the flocculation tank 30 and stirred, the floc 43 in which the metal and the metal compound contained in the wastewater are aggregated is coarsened, and the floc 43 is hardly broken and sedimented. In addition, after the flow rate of the drainage is made substantially constant in the rectification tank 80, the inclined plate 41 in the settling tank 40 suppresses the rise of the floc due to the rise of the drainage. The wastewater can be separated and removed, and the wastewater can be finally brought into a clean supernatant state. Further, a flow monitoring device 60 for controlling the discharge valve 52 for the discharge tank 50 at the subsequent stage of the sedimentation tank 40 measures the time required to reach the upper limit water level from the lower limit water level of the drainage with the opening and closing of the discharge valve 52. By comparing the required time with a preset reference time, the state of inflow of wastewater into the discharge tank 50 is monitored,
By controlling each part of the processing apparatus, it is possible to detect an abnormal state in which the flow of wastewater into the discharge tank 50 is stagnant from an increase in the required time with respect to the reference time, and to obtain the same reliability as regular monitoring in each processing stage. As a result, automatic operation can be performed reliably, and operation time can be reduced. And the neutralization stirring tank 10,
Oxidation tank 20, coagulation tank 30, sedimentation tank 40, and discharge tank 50
Is integrated as the processing tank body 100, so that the size can be significantly reduced as compared with the conventional processing apparatus.

The metal-containing wastewater treatment apparatus according to the above embodiment is configured so that the final pH value of the wastewater is adjusted by the pH adjustment device 11 so that the final pH value falls within the range of a pH suitable for discharging to the outside. However, it is also possible to make adjustments so that the pH value required by a predetermined facility for recycling the treated wastewater is required.

[0037]

EXAMPLE An example in which wastewater treatment is performed using the metal-containing wastewater treatment apparatus of the present invention will be described. In this embodiment, a case in which wastewater containing iron ions as metal ions is treated will be described. Generally, iron ions are in the following two states in a solution.

Fe ²⁺ + 2OH ⁻ ⇔Fe (OH) ₂ Fe ³⁺ + 3OH ⁻ ⇔Fe (OH) ₃ Iron ions are relatively easily dissolved in a solution when they are divalent, but have a medium pH when they are trivalent. Iron is very difficult to dissolve in a predetermined range close to the
^By oxidizing ²⁺ to Fe ³⁺ (change of depriving electrons), iron can be removed as a hardly soluble precipitate.

The Fe ²⁺ -e ^- as → Fe ³⁺ oxidation agent for oxidizing iron, common pesticides: When using the (main component sodium hypochlorite), oxidizing force produced by dissolving it in a solution Hypochlorous acid takes two kinds of dissolved forms depending on the pH of the aqueous solution. In the acidic side than ^{pH7.5, HClO + H + + e} - → 1 / in 2Cl ₂ + H ₂ O pH7.5 than alkaline _{^{side, ClO - + H 2 O +}} 2e - → Cl - + 2OH - these, ion ClO hypochlorite ^- of if the 2-electron system occurring, the oxidation of the iron is efficient, hypochlorite ion ClO ^- in order to increase the existence ratio of the solution pH to
Must be more alkaline than 7.5. These reasons and the wastewater standard of pH value for industrial wastewater (pH 5.8 ~
Considering 8.6), the pH setting range of the wastewater is 7.5 to 7.5.
8.6, and the pH of the waste water is adjusted by the pH adjusting device 11 so as to be within this range.

One example of the result of treating wastewater using the metal-containing wastewater treatment apparatus 1 having the configuration according to the embodiment as the above-mentioned pH setting range is shown in the case where no oxidizing agent is added in the metal-containing wastewater treatment apparatus 1 ( Comparative Example 1) and FIG. 4 together with the respective treatment results when a conventional metal-containing wastewater treatment apparatus that does not perform oxidation by injecting an oxidant and performing aeration is used (Comparative Example 2).
Shown in In any case, 9 ml of a polymer flocculant is added per liter of wastewater as a treatment condition. In the embodiment, a chlorine agent as an oxidant is added in an amount of 5 ml per liter of drainage, and aeration (air blowing) is performed at 100 liters per minute. Further, in Comparative Example 1, aeration was performed at 100 l per minute, but no chlorine agent was added.

As shown in FIG. 4, in the embodiment, although the iron content in the raw effluent is higher than the others, the iron content after the treatment is extremely small as compared with each comparative example. It can be seen that the effect of the oxidant injection is obtained.

[0042]

As described above, according to the present invention, the pH of wastewater containing metal and metal ions is adjusted, an oxidizing agent is injected and stirred, and the metal ions in the wastewater are oxidized as metal components. By precipitating and removing all the metal,
Regardless of the state of the pH of the wastewater, the wastewater can be adjusted to an appropriate pH and the oxidizing agent can be quickly and uniformly mixed into the wastewater by stirring, so that the oxidizing agent can efficiently oxidize metal ions. This has the effect that the oxidative precipitation of metal ions can be reliably performed. In addition, by injecting a flocculant into the wastewater that has flowed into the flocculation tank and further stirring, the flocs in which the metals and metal compounds contained in the wastewater are flocculated are coarsened, making the flocs less likely to break and sedimentation easier. This has the effect that separation from wastewater is facilitated. Furthermore, a plurality of inclined plate-like bodies are disposed in the sedimentation tank, and the substantially plate-like body rises in floc as the drainage rises with respect to drainage flowing upward from below between the plate-like bodies. By suppressing the flocculation, flocs after coagulation can be surely separated and removed from the wastewater, and finally the wastewater can be brought into a clean supernatant state, which has an effect that discharge to the outside can be performed without any problem.

Further, according to the present invention, air is blown into the wastewater flowing into the oxidation tank by the aeration device, and the metal ions are caused to oxidize air by the contact between the wastewater and the air. The oxidation by the action of the agent and the air oxidation can proceed simultaneously to promote the oxidative precipitation of metal ions, and together with the neutralization precipitation accompanying the injection of the pH adjuster, the metal ions in the wastewater can be reliably removed from the metal and / or Alternatively, it has the effect that it can be precipitated and removed as a metal compound.

According to the present invention, the discharge monitoring tank detects the upper limit water level and the lower limit water level of the discharge tank and controls the discharge valve for the discharge tank storing the wastewater from the sedimentation tank. By measuring the time from the lower water level to the upper water level, the required time from the lower water level to the upper water level is compared with a preset reference time, and the water pipes in each part of the treatment equipment are blocked and water is taken out. It is possible to detect an abnormal state where the inflow of drainage into the discharge tank, such as a clogged pump, is stagnated from an increase in the required time with respect to a reference time, and has an effect that reliability equivalent to regular monitoring in each processing stage can be obtained. . Furthermore, the total amount of treated water can be automatically measured by the flow monitoring device, and the effect is obtained that the treated water amount can be measured without installing a flow meter.

Further, according to the present invention, the scum stopper provided in the middle of the flow path from the sedimentation tank to the discharge tank prevents the foreign matter floating on the water surface of the waste water from moving to the subsequent stage, and the foreign matter on the drain water surface is also prevented. By reliably separating the wastewater from the wastewater, only the clean supernatant from the sedimentation tank is allowed to flow into the discharge tank at the subsequent stage, and the water can be discharged to the outside without any problem, and the wastewater can be reused. Has the effect of preventing clogging of the discharge path leading to foreign matter by foreign matter.

Further, according to the present invention, the amount of oxidant injected into the oxidant injector is controlled in accordance with the change in the state of inflow of wastewater into the discharge tank monitored by the flow rate monitoring device, so that the lower limit water level is set to the upper limit water level. By limiting the amount of oxidizer injected in abnormal conditions where the time required to reach the water level is longer than the reference time, it is possible to prevent the oxidizer from becoming too concentrated in wastewater that is stagnant in abnormal conditions, This has the effect of preventing the wasteful consumption of wastewater and the generation of toxic gas due to the reaction between the concentrated oxidizing agent and the wastewater.

Further, according to the present invention, the amount of coagulant injected into the coagulant injection device is controlled in accordance with the change in the state of inflow of wastewater into the discharge tank monitored by the flow rate monitoring device, and from the lower limit water level to the upper limit water level. In the abnormal state where the time required to reach the water level is longer than the reference time, the coagulant injection amount is limited to prevent the coagulant from becoming excessively concentrated in the wastewater that has been stagnated in the abnormal state. This has the effect that wasteful consumption of waste can be prevented.

Further, according to the present invention, the pH adjusting device is provided in combination with the neutralization stirring tank, and the oxidizing agent injection device and the first stirring device are provided, and are charged into the neutralization stirring tank. While adjusting the pH of the wastewater, inject the oxidizing agent and stir,
By oxidizing metal ions in the wastewater,
Regardless of the state of H, the wastewater can be adjusted to an appropriate pH, and the oxidizing agent can be quickly and uniformly mixed with the wastewater by stirring of the first stirring device. This has the effect that ions can be oxidized and metal ions can be oxidized and deposited reliably. In addition, the flocculant is injected from the coagulant injection device into the wastewater that has flowed into the coagulation tank, and further stirred by the second stirring device, whereby the flocs in which the metals and metal compounds contained in the wastewater are aggregated are coarsened, This has the effect of making the flocs less fragile and easier to settle, making it easier to separate from the wastewater. Furthermore, a plurality of inclined plates are arranged in the sedimentation tank, and for the drainage that goes up from below between the inclined plates, the inclined plates suppress the rise of the flocs due to the rise of the drainage, thereby reducing the flocs after aggregation. The wastewater can be surely separated and removed, and the wastewater can be finally brought into a clean supernatant state, so that there is an effect that the water can be discharged to the outside without any problem.

According to the present invention, an oxidizing tank is provided in front of the coagulation tank, and an aeration device is provided in the oxidizing tank, and air is blown into the wastewater in the oxidizing tank. By causing the metal ions to undergo air oxidation upon contact with water, the oxidation by the action of the oxidizing agent and the air oxidation can proceed simultaneously to promote the oxidative precipitation of the metal ions, which accompanies the injection of the pH adjusting agent. In combination with the neutralization precipitation, there is an effect that metal ions in the wastewater can be reliably precipitated and removed as a metal and / or a metal compound.

Further, according to the present invention, a discharge tank for discharging wastewater from the sedimentation tank is provided, a discharge valve of the discharge tank is controlled, and a flow monitoring device for monitoring the state of inflow of wastewater into the discharge tank. The upper and lower water levels of the discharge tank are detected, the discharge valve is opened and closed, and the required time from the lower water level to the upper water level of the wastewater is measured. Comparing the time with a preset reference time, to detect an abnormal state in which the flow of wastewater into the discharge tank is stagnant, such as a blockage of a water distribution pipe of each part of the processing apparatus or a blockage of an intake pump, from an increase in the required time relative to the reference time. This has the effect that the same reliability as that of regular monitoring in each processing stage can be obtained. Furthermore, the discharge flow can be grasped by counting the number of opening and closing of the discharge valve by the flow monitoring device, and the total amount of treated water can be automatically measured. Thus, the amount of treated water can be measured without installing a flow meter.

Further, according to the present invention, a scum stopper is provided in the middle of the flow path from the sedimentation tank to the discharge tank, and this scum stopper prevents the foreign matter floating on the water surface of the wastewater from moving to the subsequent stage. Foreign matter on the surface of the drainage water is surely separated from the wastewater, so that only the clean supernatant flows from the sedimentation tank into the discharge tank at the subsequent stage, and can be discharged to the outside without any problems.
In addition, the wastewater can be reused, and the discharge path from the discharge tank to the outside can be prevented from being clogged by foreign matter.

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of a metal-containing wastewater treatment apparatus according to one embodiment of the present invention.

FIG. 2 is a plan view of the metal-containing wastewater treatment device according to one embodiment of the present invention.

FIG. 3 is a block diagram of a metal-containing wastewater treatment device according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram of a wastewater treatment result of the metal-containing wastewater treatment device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal-containing wastewater treatment apparatus 10 Neutralization stirring tank 11 pH adjuster 11a pH sensor 12 Oxidizing agent injection device 13 First stirring device 20 Oxidation tank 21 Aeration device 30 Coagulation tank 31 Coagulant injection device 32 Second stirring device 40 Precipitation tank 41 Inclined plate 42 Scum stopper 43 Flock 44 Foreign matter 45 Sludge discharge valve 50 Discharge tank 51 Water level sensor 52 Discharge valve 60 Flow monitoring device 70 Transformation tank 80 Rectification tank 80a Partition plate 100 Treatment tank body 110 Water intake pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/56 C02F 1/56 K 1/72 1/72 Z 1/74 1/74 Z 9/00 502 9/00 502R 502P 502Z 503 503G 504 504B F term (reference) 4D015 BA19 BA22 BA23 BA24 CA17 DB01 EA03 EA32 FA01 FA24 FA25 FA28 4D038 AA08 AB66 BA04 BB16 BB18 4D050 AA13 AB55 BB01 BA02 BA02 BA08 BA02 BA08 EA03 EA32 FA01 FA24 FA25 FA28

Claims (10)

[Claims] 1. A metal-containing wastewater treatment method for removing at least metal and metal ions from wastewater containing predetermined metals and / or metal ions, wherein a predetermined pH adjuster is injected into the wastewater to adjust the pH of the wastewater.
Is adjusted within a preset range, a predetermined oxidizing agent is injected from the oxidizing agent injection device into the wastewater after the pH adjustment, and the mixture is stirred to oxidize metal ions in the wastewater to form a metal and / or a metal compound. The wastewater in the precipitated state is allowed to flow into a predetermined flocculation tank, a predetermined flocculant is poured into the wastewater and stirred, and the metal component is flocculated as floc. The wastewater is allowed to flow into a predetermined sedimentation tank that fits, and the drainage is passed from below to above between a plurality of substantially plate-like bodies arranged in an inclined state at a predetermined interval in the sedimentation tank, and the flocs in the drainage are drained from the substantially plate-like plate. A method for treating metal-containing wastewater, comprising separating the wastewater from the wastewater in a form and obtaining the supernatant of the wastewater at the upper part of the sedimentation tank. 2. The metal-containing wastewater treatment method according to claim 1, wherein the wastewater after the injection of the oxidizing agent flows into a predetermined oxidation tank, and a predetermined aeration device for the wastewater in the oxidation tank. A method for treating metal-containing wastewater, comprising: introducing air into the coagulation tank after injecting air to oxidize metal ions in the wastewater. 3. The metal-containing wastewater treatment method according to claim 1 or 2, wherein the supernatant of the wastewater in the sedimentation tank is allowed to flow into a predetermined discharge tank, and a predetermined flow rate monitoring device is configured so that the wastewater is discharged from the discharge tank. When the upper limit water level is reached, the discharge valve of the discharge tank is opened to discharge the drainage to the outside, and when the drainage reaches the lower limit water level of the discharge tank, the discharge valve is closed, while the drainage level is lower. A method for treating metal-containing wastewater, comprising: measuring a time from when the water reaches an upper limit water level to monitor a state of wastewater flowing into a discharge tank. 4. The metal-containing wastewater treatment method according to claim 3, wherein a foreign matter floating on the water surface by a scum stopper provided in the middle of a flow path from the sedimentation tank to the discharge tank of the supernatant of the wastewater. A metal-containing wastewater treatment method, comprising separating water from the supernatant of the wastewater. 5. The metal-containing wastewater treatment method according to claim 1, wherein the oxidation from the oxidizing agent injection device is performed based on a result of monitoring a state of wastewater flowing into a discharge tank by the flow monitoring device. A method for treating metal-containing wastewater, comprising controlling the injection amount of an agent. 6. The method for treating a metal-containing wastewater according to claim 1, wherein the coagulation from the coagulant injection device is performed based on a result of monitoring a state of inflow of wastewater into a discharge tank by the flow rate monitoring device. A method for treating metal-containing wastewater, comprising controlling the injection amount of an agent. 7. A metal-containing wastewater treatment apparatus for removing at least metal and metal ions from wastewater containing metal and metal ions, wherein the wastewater is supplied to a neutralization stirring tank, and the wastewater in the neutralization stirring tank is supplied to the neutralization stirring tank. On the other hand, a pH adjuster for injecting a predetermined pH adjuster to adjust the pH of the wastewater within a preset range, and an oxidizer for injecting a predetermined oxidant into the pH-adjusted wastewater in the neutralization stirring tank. An injection device, a first stirring device disposed in the neutralization stirring tank and stirring the wastewater together with a pH adjuster and an oxidizing agent, a predetermined coagulation tank into which the stirred wastewater flows, and the coagulation tank A coagulant injection device for injecting a predetermined amount of coagulant into the wastewater in the inside, a second stirring device disposed in the coagulation tank and stirring the wastewater together with the coagulant, and connected to the coagulation tank. Installed and stirred from the coagulation tank A predetermined sedimentation tank into which the drained water flows, and a plurality of substantially plate-like bodies arranged in an inclined state at predetermined intervals in the sedimentation tank, and are passed between the substantially plate-like bodies from below. A metal-containing wastewater treatment device, comprising: a slant plate that separates flocs of metal condensed in the wastewater from the wastewater so that the supernatant of the wastewater is accumulated above the sedimentation tank. 8. The metal-containing wastewater treatment device according to claim 7, wherein a predetermined oxidation tank is provided in front of the coagulation tank and into which an oxidizing agent is injected and agitated wastewater flows. A predetermined aerator for injecting air into the wastewater in the tank to oxidize metal ions in the wastewater with air, wherein the wastewater flows into the coagulation tank from the oxidation tank. . 9. The metal-containing wastewater treatment device according to claim 7 or 8, wherein the wastewater supernatant in the sedimentation tank flows in, and is discharged to the outside as needed. When the upper limit water level of the discharge tank is reached, the discharge valve of the discharge tank is opened to discharge the wastewater to the outside, and when the wastewater reaches the lower limit water level of the discharge tank, the discharge valve is closed while the drainage valve is closed. A metal-containing wastewater treatment device, comprising: a predetermined flow rate monitoring device that measures a time until the water reaches the upper limit water level from the lower limit water level and monitors the state of wastewater flowing into the discharge tank. 10. The metal-containing wastewater treatment device according to claim 9, wherein the wastewater is disposed in the middle of a flow path from the sedimentation tank to the discharge tank of the supernatant of the wastewater to remove foreign substances floating on the water surface. A metal-containing wastewater treatment device comprising a scum stopper that separates from a supernatant.