JP2010269249A - Method and apparatus for treating heavy metal-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating heavy metal-containing water capable of securely removing a heavy metal from the heavy metal-containing water at a low cost and low energy using an artificial marsh and stably removing the heavy metal over a long period of time, and an apparatus for treating the heavy metal-containing water. <P>SOLUTION: The method for treating the heavy metal-containing water for removing the heavy metal from the heavy metal-containing water includes the steps of: passing the heavy metal-containing water through a penetration type or an underflow type artificial marsh 20; reducing a sulfate ion with sulfuric acid reducing bacteria to generate a sulfide ion at the artificial marsh 20; causing the heavy metal to react with the sulfide ion to generate, settle and separate sulfide; and supplying an organic substance to the artificial marsh 20 to activate the sulfuric acid reducing bacteria. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for treating heavy metal-containing water and an apparatus for treating heavy metal-containing water that remove heavy metals from heavy metal-containing water containing heavy metals such as Zn, Cu, Fe, Cd, and Pb.

Examples of the heavy metal-containing water containing the above-mentioned heavy metals include mine wastewater, factory waste liquid, industrial waste treatment site leachate, road drainage, and the like. Conventionally, many methods for removing heavy metals from these heavy metal-containing waters have been proposed.
For example, Patent Document 1 proposes a method of neutralizing acidic wastewater by passing through a tower filled with limestone. Patent Document 2 proposes a method in which calcium carbonate is added and the pH is raised to about 6 to remove most of iron, copper and zinc, and then the residual zinc and the like are removed by raising the pH to 8.4 with caustic soda. Has been.

Furthermore, in Patent Document 3, wastewater treatment materials such as rock wool and alkaline earth metals are sprayed, or wastewater is passed through a layer filled with these wastewater treatment materials, and the pH is raised to 6 to 8, and heavy metals such as iron are added. A method for removing it as a hydroxide has been proposed.
Moreover, in the processing method using such a chemical | medical agent, since the management cost of the equipment which isolate | separates and disposes of the deposit which arises when neutralizing requires great management cost, for example, patent document 4 has a low-cost management method. Proposed.

On the other hand, as a method for removing organic substances and the like contained in waste water, a treatment method using an artificial wetland has been proposed as disclosed in, for example, Patent Documents 5 and 6.
Non-Patent Document 1 proposes a method for removing heavy metals from heavy metal-containing water using the above-described artificial wetland.

JP 59-016591 A Japanese Patent Laid-Open No. 01-099688 International Publication No. 2002/079100 Japanese Patent Laid-Open No. 06-190398 JP 2000-005777 A JP 2008-0668211 A

Robinson, J.D.F., Robb, G.A. (1995). Methods for the control and treatment of acid mine drainage.Coal Inter., P.152-156

  By the way, as disclosed in Patent Documents 1-3, in a treatment method using a neutralizing agent or the like, facilities such as a neutralization facility, a thickener (precipitation device), and a press (dehydration device) are required. A large amount of money and labor are required for processing. Moreover, since the sediment produced | generated by neutralization has bad sedimentation property and dehydration property, and a volume becomes large, a huge expense and labor are required also for processing of sediment itself. In addition, with zinc and the like, it has been difficult to reduce the concentration in water to 2 mg / l or less by the removal method using calcium carbonate.

On the other hand, as disclosed in Patent Documents 5 and 6, in water treatment using artificial wetlands, water can be treated at low cost and low energy. Mainstream.
Non-Patent Document 1 proposes a method of filling artificial wetlands with compost (organic fertilizer) and removing heavy metals as sulfides by the action of redox bacteria present in the artificial wetlands. However, when all the compost is decomposed by redox bacteria after long-term use, the constructed wetland becomes aerobic and the function of the redox bacteria deteriorates. For this reason, there existed a problem that removal of heavy metal cannot be performed continuously over a long period of time.

  The present invention has been made in view of the above-mentioned circumstances, and can remove heavy metals reliably from heavy metal-containing water at low cost and low energy using an artificial wetland and stably remove heavy metals over a long period of time. An object of the present invention is to provide a method for treating heavy metal-containing water and a treatment apparatus for heavy metal-containing water.

  In order to solve such problems and achieve the above-mentioned object, a method for treating heavy metal-containing water according to the present invention is a method for treating heavy metal-containing water that removes heavy metal from heavy metal-containing water, wherein A step of passing the heavy metal-containing water through an underflow type constructed wetland; a step of producing sulfate ions by reducing sulfate ions by sulfate-reducing bacteria in the constructed wetland; and the reaction of the heavy metals with the sulfide ions And generating a heavy metal sulfide for sedimentation and supplying organic matter to the constructed wetland to activate the sulfate-reducing bacteria.

  According to the method for treating heavy metal-containing water having this configuration, the step of reducing sulfate ions by sulfate-reducing bacteria in an artificial wetland to generate sulfide ions, and the heavy metal is reacted with the sulfide ions to sulfidize heavy metals. A step of generating and sedimenting a product, so that the heavy metal-containing water can be removed by passing the heavy metal-containing water through the artificial wetland. In addition, as a heavy metal removed, what produces | generates the sulfide which is easy to isolate | separate from water, such as Zn, Cu, Fe, Cd, Pb, for example is preferable.

  In addition, since the organic wetland is provided with a step of supplying organic matter to the artificial wetland in order to activate the sulfate-reducing bacteria, the artificial wetland is maintained anaerobically and the action of the sulfate-reducing bacteria is maintained over a long period of time. Thus, heavy metals can be removed stably over a long period of time. Examples of organic substances supplied to the constructed wetland include commercially available drugs such as lactic acid, lactate, glucose, methanol, ethanol, acetic acid, formic acid, and sucrose, or compost, fertilizer, culture soil, biodegradable plastic, etc. Recycled materials etc. can be used.

Here, it is preferable to have a step of filling the artificial wetland with an organic material in advance.
In this case, before passing the heavy metal-containing water through the constructed wetland, the sulfate-reducing bacteria are activated by filling the constructed wetland with organic substances such as compost in advance, and the heavy metal is stably added from the initial stage. It can be removed.

Moreover, it is preferable to have the process of previously filling the artificial wetland with the sulfate-reducing bacteria.
In this case, before passing the heavy metal-containing water through the constructed wetland, the sulfate-reducing bacteria are filled in the constructed wetland in advance, so that many sulfate-reducing bacteria are present in the constructed wetland, thereby removing heavy metals. Thus, heavy metal can be removed stably from the initial stage.

And a step of measuring an oxidation-reduction potential inside the constructed wetland, supplying an organic matter to the constructed wetland so that the oxidation-reduction potential is in a predetermined range, and maintaining the constructed wetland anaerobically; It is preferable to do.
In this case, by measuring the oxidation-reduction potential of the constructed wetland and supplying the organic matter to the artificial wetland so that the oxidation-reduction potential is within a predetermined range, the constructed wetland is reliably maintained anaerobically and the sulfate-reducing bacteria are activated. Will be. This makes it possible to stably remove heavy metals over a long period of time.

Moreover, it is preferable that an aquatic plant is planted in the artificial wetland.
When aquatic plants such as reeds are planted in the constructed wetland, nutrients are supplied to the constructed wetland through the roots of the aquatic plant, and the constructed wetland becomes anaerobic and the sulfate-reducing bacteria are activated. Will be. Therefore, in the step of supplying organic matter to the artificial wetland, the amount of organic matter to be supplied can be reduced. When nutrient salts are reduced, nutrients in the constructed wetland are consumed and oxygen is supplied to the rhizosphere, which may cause the constructed wetland to move to aerobic. For this reason, when planting an aquatic plant, it is preferable to have the process of measuring the oxidation-reduction potential inside the artificial wetland as described above.

Furthermore, it is preferable to provide an aerobic second constructed wetland downstream of the constructed wetland and to remove organic substances in the second constructed wetland.
When the organic matter is excessively supplied to the artificial wetland, the organic matter is contained in the treated water from which heavy metals have been removed. Therefore, by providing the aerobic second constructed wetland on the downstream side of the constructed wetland, it becomes possible to remove the excessively supplied organic matter. Therefore, it is not necessary to accurately adjust the supply amount of organic matter in the constructed wetland, and heavy metals can be efficiently removed.

  The treatment apparatus for heavy metal-containing water according to the present invention is a treatment apparatus for heavy metal-containing water that removes heavy metals from heavy metal-containing water, the seepage-type or downflow-type constructed wetland through which the heavy metal-containing water passes, and the artificial An organic substance supply means for supplying an organic substance to the wetland.

  According to the apparatus for treating heavy metal-containing water having this configuration, the apparatus includes an infiltration-type or downflow-type artificial wetland through which the heavy metal-containing water passes, and an organic substance supply unit that supplies organic substances to the artificial wetland. Therefore, by appropriately supplying the organic matter to the artificial wetland, it becomes possible to keep the artificial wetland anaerobic and to activate the sulfate-reducing bacteria over a long period of time. Accordingly, heavy metals can be stably removed over a long period of time by the action of sulfate-reducing bacteria in the constructed wetland.

Also, an oxidation-reduction potential measuring device that measures the oxidation-reduction potential inside the constructed wetland, and a control unit that controls the amount of organic matter supplied by the organic matter supply means based on the measurement value of the oxidation-reduction potential measuring device. It is preferable.
In this case, the control unit controls the amount of organic matter supplied by the organic matter supply means based on the measured value of the redox potential measuring device that measures the redox potential inside the constructed wetland, so that the constructed wetland is surely anaerobic. The sulfate-reducing bacteria are activated and the heavy metal can be stably removed over a long period of time. In addition, it is possible to prevent supplying more than necessary organic matter to the artificial wetland, and the amount of organic matter used can be reduced.

Here, it is preferable that the organic substance supply means includes a liquid feed pump for transferring the organic substance-containing liquid, and a supply pipe disposed inside the artificial wetland.
In this case, the organic matter can be supplied to the artificial wetland in a liquid state, and the supply amount of the organic matter can be accurately controlled by controlling the operation of the liquid feeding pump. In addition, since the organic matter is supplied from the supply pipe disposed inside the constructed wetland, the organic matter can be efficiently supplied to the entire constructed wetland, and the sulfate-reducing bacteria can be activated in the entire constructed wetland.

Furthermore, it is preferable that an aerobic second constructed wetland is provided downstream of the constructed wetland.
In this case, even if the organic matter is excessively supplied to the artificial wetland by the organic matter supply means, the organic matter can be removed in the aerobic second artificial wetland. Therefore, there is no need to particularly limit the amount of organic matter supplied by the organic matter supplying means, and heavy metals can be efficiently removed.

  According to the present invention, a method for treating heavy metal-containing water capable of reliably removing heavy metal from heavy metal-containing water at low cost and low energy using an artificial wetland and capable of stably removing heavy metal over a long period of time. And the processing apparatus of heavy metal containing water can be provided.

It is a schematic explanatory drawing of the processing apparatus of the heavy metal containing water which is embodiment of this invention. It is explanatory drawing of the supply pipe | tube of the organic substance supply means with which the processing apparatus for heavy metal containing water shown in FIG. 1 was equipped. It is explanatory drawing which shows control of the waste water pump with which the heavy metal containing water processing apparatus shown in FIG. 1 was equipped, and the organic matter pump. It is a schematic explanatory drawing of the processing apparatus of the heavy metal containing water which is other embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an apparatus for treating heavy metal-containing water according to an embodiment of the present invention.
The heavy metal-containing water treatment apparatus 10 removes heavy metals from heavy metal-containing water containing heavy metals such as Zn, Cu, Fe, Cd, and Pb. In this embodiment, zinc (Zn) is used as the heavy metal. Zinc (Zn) is removed from mine wastewater containing water. Note that mine wastewater usually also contains sulfate ions.

  As shown in FIG. 1, the heavy metal-containing water treatment apparatus 10 according to the present embodiment includes a penetrating artificial wetland 20, wastewater supply means 15 for supplying mine wastewater to the artificial wetland 20, and organic matter in the artificial wetland 20. The organic substance supply means 30 for supplying the redox potential and the redox potential measuring device 40 for measuring the redox potential inside the constructed wetland 20 are provided.

  The constructed wetland 20 includes a device main body 21 having a bottomed cylindrical shape, a gravel layer 23 spread on the bottom of the device main body 21, and a sand layer 24 provided above the gravel layer 23. In addition, an active layer 25 in which sulfate-reducing bacteria are activated is provided in the lower layer portion of the sand layer 24. In addition, a discharge port 22 for discharging treated water treated in the artificial wetland 20 is provided in the upper part of the apparatus main body 21. Furthermore, in this embodiment, as shown in FIG. 1, an aquatic plant 27 such as reed is planted on the top of the sand layer 24.

  The wastewater supply means 15 includes a wastewater pump 16 that transfers mine wastewater, and a supply pipe 17 that supplies the mine wastewater into the artificial wetland 20. In the present embodiment, as shown in FIG. 1, the supply pipe 17 is disposed at the bottom of the apparatus main body 21, that is, below the gravel layer 23 of the artificial wetland 20. Therefore, the mine wastewater is sequentially transferred upward from the lower layer side of the gravel layer 23 of the constructed wetland 20 and is discharged to the outside from the discharge port 22 provided in the upper part of the apparatus main body 21 after passing through the sand layer 24. It is said that. The mine wastewater to be treated contains almost no organic matter.

The organic substance supply means 30 includes an organic substance pump 31 that transfers liquid organic substance, and a supply pipe 32 that supplies the liquid organic substance into the artificial wetland 20. In the present embodiment, as shown in FIG. 1, the supply pipe 32 is disposed below the sand layer 24 of the artificial wetland 20, and the above-described active layer 25 is formed in the portion where the organic matter is supplied.
Here, as shown in FIGS. 1 and 2, the supply pipe 32 is provided by a vertical pipe 33 extending in the vertical direction, a horizontal pipe 34 extending in the horizontal direction below the sand layer 24, and a branch from the horizontal pipe 34. A plurality of branch pipes 35, and supply holes 36 for supplying organic substances to the upper side of the horizontal pipes 34 and the branch pipes 35 are formed so that the organic substances can be widely supplied into the constructed wetland 20. ing.

  Examples of the organic substance supplied by the organic substance supplying means 30 include lactic acid, lactate, glucose, methanol, ethanol, acetic acid, formic acid, sucrose, compost, fertilizer, culture soil, biodegradable plastic, and the like. In this embodiment, lactic acid that is liquid and can be easily transferred by an organic pump is used.

The oxidation-reduction potential measuring device 40 includes an electrode unit 41 embedded in the constructed wetland 20 and a calculation unit 42 that calculates a potential. The oxidation-reduction potential measuring device 40 is connected to the control unit 19 that controls the operations of the waste water pump 16 of the waste water supply unit 15 and the organic matter pump 31 of the organic matter supply unit 30.
In the control unit 19, the operations of the wastewater pump 16 and the organic matter pump 31 are controlled based on the redox potential of the artificial wetland 20 measured by the redox potential measuring device 40.

  Here, the control operation of the wastewater pump 16 and the organic matter pump 31 in the control unit 19 will be described with reference to FIG. In the constructed wetland 20, the artificial wetland 20 is aerobic when the redox potential is positive, and the artificial wetland 20 is anaerobic when the redox potential is negative. Since the sulfate-reducing bacteria used in the heavy metal-containing water treatment apparatus 10 according to the present embodiment is activated in anaerobic manner, in this embodiment, wastewater is maintained so as to keep the constructed wetland 20 anaerobic. The operations of the pump 16 and the organic matter pump 31 are controlled.

Specifically, as shown in FIG. 3, when the oxidation-reduction potential exceeds +100 mV, the operation of the wastewater pump 16 is stopped. Thereby, the supply of mine wastewater with less organic matter into the constructed wetland 20 is stopped. Further, when the oxidation-reduction potential becomes +100 mV or less, the operation of the waste water pump 16 is started.
When the oxidation-reduction potential is −100 mV or more, the organic matter pump 31 is activated to reduce the oxidation-reduction potential of the constructed wetland 20. On the other hand, when the oxidation-reduction potential falls below −110 mV, the organic matter is excessively supplied, so the organic matter pump 31 is stopped. As a result, the oxidation-reduction potential increases.
By performing such control, the oxidation-reduction potential of the constructed wetland 20 is adjusted to around −105 mV, and the constructed wetland 20 is kept anaerobically.

Below, the processing method of the heavy metal containing water using the above-mentioned heavy metal containing water processing apparatus 10 is demonstrated.
First, before supplying mine wastewater into the artificial wetland 20, organic matter such as compost is supplied into the artificial wetland 20 in advance. At this time, for example, by mixing sludge from a sewage treatment plant, a large number of sulfate-reducing bacteria can be arranged inside the artificial wetland 20.

Next, the wastewater pump 16 is moved to supply mine wastewater upward from the bottom of the constructed wetland 20. Then, sulfate ions contained in mine wastewater are reduced by sulfate-reducing bacteria, and sulfide ions are generated. And this sulfide ion and zinc (Zn) which is a heavy metal react, and zinc sulfide (ZnS) is produced | generated. Since this zinc sulfide is hardly soluble in water, it is precipitated and separated from water. The reaction formula up to the production of zinc sulfide by sulfate-reducing bacteria is shown below.
2CH ₂ O + SO ₄ ²⁻ → H ₂ S + 2HCO ₃ ⁻
H ₂ S + Zn ²⁺ → ZnS ↓ + 2H ⁺

  The treated water from which zinc has been settled and separated by the action of sulfate-reducing bacteria further rises in the sand layer 24 and is discharged to the outside from the discharge port 22 provided in the upper part of the apparatus main body 21. Also, zinc sulfide will settle to the bottom of the sand layer 24.

Here, by supplying an organic substance (lactic acid) into the artificial wetland 20 using the organic substance supply means 30, the artificial wetland 20 is maintained anaerobically and the sulfate-reducing bacteria are activated.
In the present embodiment, as described above, the oxidation-reduction potential inside the artificial wetland 20 is measured, and the supply amount of organic matter is controlled so that the oxidation-reduction potential becomes a predetermined value (−105 mV). 20 is kept anaerobically.

  As described above, it is possible to remove zinc from mine wastewater containing zinc as a heavy metal using the constructed wetland 20.

  According to the heavy metal-containing water treatment apparatus 10 and the heavy metal-containing water treatment method of the present embodiment configured as described above, the mine wastewater is passed through the constructed wetland 20, and Because the sulfate ions contained in the mine wastewater are reduced by the action to produce sulfide ions, the heavy metal zinc reacts with the sulfide ions to form the poorly water-soluble zinc sulfide, and is separated by sedimentation. Zinc, which is a heavy metal, can be reliably removed using the constructed wetland 20.

Moreover, since the organic substance supply means 30 which supplies organic substance (in this embodiment, lactic acid) with respect to the artificial wetland 20 is provided, the artificial wetland 20 is maintained anaerobic and the effect | action of a sulfate reducing bacterium is maintained over a long period of time. As a result, zinc, which is a heavy metal, can be removed stably over a long period of time.
Furthermore, in this embodiment, since the organic substance supplied by the organic substance supply means 30 is liquid lactic acid, the supply amount of the organic substance (lactic acid) can be easily and accurately controlled by controlling the operation of the organic substance pump 31. Can be adjusted.

  In the present embodiment, the oxidation-reduction potential measuring device 40 that measures the oxidation-reduction potential inside the constructed wetland 20, and the wastewater pump 16 of the wastewater supply means 15 and the organic substance supply based on the measurement value of the oxidation-reduction potential measurement device 40. And a control unit 19 that controls the operation of the organic matter pump 31 of the means 30, and the control unit 19 is configured to keep the constructed wetland 20 anaerobically, so that sulfate-reducing bacteria are stably activated. As a result, it is possible to stably remove zinc which is a heavy metal over a long period of time. Furthermore, it is possible to prevent an unnecessary amount of organic matter from being supplied to the constructed wetland 20.

  In the present embodiment, the artificial wetland 20 is pre-filled with organic matter such as compost and mixed with sludge and the like of a sewage treatment plant containing sulfate-reducing bacteria. A large number of sulfate-reducing bacteria are arranged, and the sulfate-reducing bacteria are activated by the organic matter, so that it becomes possible to efficiently treat the mine wastewater from the initial stage. Moreover, the usage-amount of the lactic acid supplied in the artificial wetland 20 by the organic substance supply means 30 can be reduced.

Furthermore, in this embodiment, since aquatic plants 27 such as reed are planted in the sand layer 24 of the constructed wetland 20, nutrients are supplied into the constructed wetland 20 from the roots of the aquatic plant 27. The artificial wetland 20 becomes anaerobic and the sulfate-reducing bacteria are activated, so that the heavy metal zinc can be efficiently removed. Moreover, the usage-amount of the lactic acid supplied by the organic substance supply means 30 can be reduced.
In the winter season (low temperature environment) in which the aquatic plant 27 dies out, the effect of activating sulfate-reducing bacteria by the aquatic plant 27 is reduced, so that the organic substance supply means 30 actively supplies lactic acid. Become. Thereby, the removal process of stable zinc can be performed throughout the year.

  Further, in the present embodiment, the supply pipe 32 of the organic substance supply means 30 includes a horizontal pipe 34 extending horizontally in the lower part of the sand layer 24 and a plurality of branch pipes 35 branched from the horizontal pipe 34. Therefore, even when a small amount of organic matter is supplied, it can be supplied so as to spread over the entire surface of the artificial wetland 20 and the sulfate-reducing bacteria can be activated reliably.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, as shown in FIG. 4, a second constructed wetland 120 held aerobically may be provided on the downstream side of the constructed wetland 20 that keeps anaerobic and removes heavy metals. In this case, it is possible to remove the organic matter supplied excessively in the constructed wetland 20 in the second constructed wetland 120. Therefore, there is no need to particularly limit the amount of organic matter supplied by the organic matter supplying means, and heavy metals can be efficiently removed.

  Moreover, although demonstrated as what treats the mine wastewater which contains zinc as a heavy metal, it is not limited to this, For example, it may be a factory waste liquid, the leachate of an industrial waste disposal site, road drainage, etc. Moreover, as heavy metal, you may remove Cu, Fe, Cd, Pb, etc. other than zinc. The heavy metal to be removed is preferably a heavy metal that is easily separated from the treated water because the sulfide is hardly water-soluble.

Furthermore, although it demonstrated as what used lactic acid as an organic substance supplied to artificial wetlands by an organic substance supply means, it is not limited to this, Lactate, glucose, methanol, ethanol, acetic acid, formic acid, sucrose, compost Other organic substances such as fertilizer, culture soil, and biodegradable plastic may be used.
Moreover, the structure of an organic substance supply means and a wastewater supply means is not limited to this embodiment, What is necessary is just a structure which can supply organic substance and wastewater (heavy metal containing water) with respect to artificial wetland.

Moreover, although it demonstrated as what used an osmosis | permeation type constructed wetland, it is not limited to this, You may employ | adopt an underground type constructed wetland.
Furthermore, although the apparatus main body was demonstrated as what has a bottomed cylindrical shape, it is not limited to this, The shape of an apparatus main body can be designed arbitrarily.

DESCRIPTION OF SYMBOLS 10 Heavy metal containing water processing apparatus 19 Control part 20 Artificial wetland 27 Aquatic plant 30 Organic substance supply means 31 Organic substance pump (liquid feed pump)
32 Supply pipe 40 Redox potential measuring device

Claims (10)

A method for treating heavy metal-containing water that removes heavy metal from heavy metal-containing water,
Passing the heavy metal-containing water through an infiltration-type or downflow-type constructed wetland;
In the constructed wetland, a step of generating sulfate ions by reducing sulfate ions by sulfate-reducing bacteria;
Reacting the heavy metal with the sulfide ions to form a heavy metal sulfide to precipitate and separate;
Supplying organic matter to the constructed wetland in order to activate the sulfate-reducing bacteria,
A method for treating heavy metal-containing water, comprising:   The method for treating heavy metal-containing water according to claim 1, further comprising a step of previously filling the artificial wetland with an organic substance.   The method for treating heavy metal-containing water according to claim 1 or 2, further comprising a step of preliminarily filling the artificial wetland with the sulfate-reducing bacteria. Measuring the redox potential inside the constructed wetland,
The organic matter is supplied to the artificial wetland so that the oxidation-reduction potential falls within a predetermined range, and the artificial wetland is maintained in an anaerobic manner. Of treating heavy metal-containing water.   The method for treating heavy metal-containing water according to any one of claims 1 to 4, wherein an aquatic plant is planted in the artificial wetland.   The aerobic second constructed wetland is provided downstream of the constructed wetland, and the organic wetland is removed in the second constructed wetland. 6. The heavy metal containing water treatment method of description. A heavy metal-containing water treatment apparatus for removing heavy metals from heavy metal-containing water,
Seepage-type or subsurface-type constructed wetlands through which the heavy metal-containing water passes,
An organic substance supply means for supplying an organic substance to the constructed wetland;
An apparatus for treating heavy metal-containing water. A redox potential measuring device for measuring the redox potential inside the constructed wetland;
A control unit for controlling the amount of organic substance supplied by the organic substance supply means based on the measured value of the oxidation-reduction potential measuring device;
The apparatus for treating heavy metal-containing water according to claim 7, comprising:   The said organic substance supply means is equipped with the liquid feeding pump which transfers organic substance containing liquid, and the supply pipe arrange | positioned at the bottom part of the said artificial wetland, The Claim 7 or Claim 8 characterized by the above-mentioned. Equipment for treating heavy metal-containing water.   The apparatus for treating heavy metal-containing water according to any one of claims 7 to 9, wherein an aerobic second constructed wetland is provided downstream of the constructed wetland.

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