JP4101116B2 - Water treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water treatment apparatus, and more particularly to a water treatment apparatus that removes unnecessary components in water to be treated containing nitrogen compounds.
[0002]
[Prior art]
Conventionally, it is well known that nitrogen compounds exist as one of the causes of eutrophication of rivers and lakes.
[0003]
Conventionally, techniques for efficiently removing nitrogen compounds by performing electrolytic treatment instead of biological treatment on domestic wastewater and factory wastewater have been disclosed in Patent Documents 1 to 3, etc. . In this electrolytic treatment, for example, nitrate ions, which are a kind of nitrogen oxide, are removed from the water to be treated as nitrogen gas through nitrite ions and ammonia in this order. In these patent documents, the electrode material used in the electrolytic treatment is a conductor containing Group Ib or Group Ib of the periodic table. There is also disclosed a technique for efficiently removing nitrogen oxides by containing ions, converting the halogen ions into hypohalous acid, and reacting with ammonia.
[0004]
[Patent Document 1]
JP 2002-248473 A
[0005]
[Patent Document 2]
JP 2002-248474 A
[0006]
[Patent Document 3]
JP 2003-53365 A
[0007]
[Problems to be solved by the invention]
In addition, about such a water treatment apparatus, it is always calculated | required that management is easy.
[0008]
The present invention has been conceived in view of such circumstances, and an object thereof is to provide a water treatment device that can be easily managed.
[0009]
[Means for Solving the Problems]
A water treatment device according to an aspect of the present invention is a water treatment device for water to be treated containing a nitrogen compound, a housing portion for housing the water to be treated, and an electrode pair provided in the housing portion. A chloride ion adding means for adding a substance that provides chloride ions in a solution to the containing portion, an operation for electrolyzing water to be treated contained in the containing portion of the electrode pair, and the chloride Control means for controlling the addition operation of the chloride ion adding means, the control means, after a predetermined time of electrolysis of the water to be treated by the electrode pair, the chloride ion adding means to the container to the storage unit And adding a substance that provides chloride ions.
[0010]
According to one aspect of the present invention, when electricity is supplied to the electrode pair in the housing portion, nitrate ions are reduced at the cathode and converted to ammonia through nitrite ions. This ammonia is removed from the water to be treated as nitrogen gas by hypochlorous acid generated at the anode. In addition, since a substance that provides chloride ions is introduced into the container after a predetermined time has elapsed since the start of such an electrolytic reaction, nitrite ions generated by reduction of nitrate ions are converted into ammonia. It is possible to suppress oxidation by hypochlorous acid generated from the chloride ions before being reduced to nitrate ions.
[0011]
Thereby, the removal efficiency of the nitrogen oxide in a water treatment apparatus can be improved, From this, the water treatment apparatus which should be installed can be made into a smaller scale than before. Therefore, as a result, management of the water treatment apparatus can be facilitated.
[0012]
In the water treatment apparatus of the present invention, the predetermined time after the electrolysis of the water to be treated by the electrode pair is a time during which 1/3 or more of all nitrogen compounds contained in the water to be treated become ammoniacal nitrogen. It is preferable that
[0013]
Further, the water treatment apparatus of the present invention further includes a compound detection means for detecting whether or not the water to be treated in the container contains a predetermined compound containing chromium, lead, molybdenum, or vanadium, The control means is provided on the condition that the compound detection means detects that the predetermined compound is contained in the water to be treated in the container, and after the predetermined time of the electrolysis of the water to be treated by the electrode pair, It is preferable that the substance is added to the container.
[0014]
Thereby, when the element which consumes hypochlorite ion like chromium, lead, molybdenum, or vanadium is contained, consumption of the hypochlorite ion of the element can be suppressed.
[0015]
The water treatment apparatus of the present invention further includes nitrate nitrogen concentration detection means for detecting the nitrate nitrogen concentration of the water to be treated in the storage section, and the control means includes the nitrate nitrogen concentration detection means. On the condition that it is detected that the nitrate nitrogen concentration in the water to be treated is equal to or higher than a predetermined concentration, after a predetermined time of electrolysis of the water to be treated by the electrode pair, It is preferable to add a substance.
[0016]
In the water treatment apparatus of the present invention, the predetermined concentration for the nitrate nitrogen concentration is preferably 2000 milligrams / liter as the nitrogen concentration.
[0017]
Further, the water treatment apparatus of the present invention further includes an acidic reagent charging unit for charging an acidic reagent into the storage unit, and a total nitrogen concentration detection unit for detecting the total nitrogen concentration of the water to be treated in the storage unit, The control means controls the amount of the acidic reagent input by the acidic reagent input means according to at least one of the total nitrogen concentration of the water to be treated in the container, the current value flowing in the electrode pair, and the total nitrogen concentration. It is preferable to do.
[0018]
A water treatment device according to another aspect of the present invention is a water treatment device for water to be treated containing a nitrogen compound, a housing portion for housing the water to be treated, and an electrode pair provided in the housing portion. And a chloride ion addition means for adding a substance that provides chloride ions in a solution to the container, an operation for electrolyzing water to be treated contained in the container of the electrode pair, and Control means for controlling the addition operation of the chloride ion addition means, and the storage portion is composed of a plurality of electrolytic cells arranged in a predetermined order, and the water to be treated passes between the plurality of electrolytic cells. It further includes a connecting pipe connected so as to be possible, and water supply means for sending the water to be treated between the plurality of electrolytic cells in the predetermined order.
[0019]
According to another aspect of the present invention, continuous processing in a plurality of electrolytic cells is possible.
Thereby, since the tank which should be connected to a water treatment apparatus called the tank which stores the to-be-processed water for sending to an accommodating part can be reduced, management of the said water treatment apparatus can be made easy.
[0020]
Moreover, it is preferable that the water treatment apparatus of this invention further contains the thermal radiation means connected to each of these electrolytic cells, or provided in the said connection pipe.
[0021]
The water treatment apparatus of the present invention further includes temperature detection means for detecting the temperature of the water to be treated in at least one of the plurality of electrolytic tanks, and the control means detects the temperature detection means. It is preferable to control the value of the current flowing through the electrode pair based on the temperature.
[0022]
A water treatment device according to still another aspect of the present invention is a water treatment device for water to be treated containing a nitrogen compound, a housing portion for housing the water to be treated, and an electrode provided in the housing portion. A pair, a chloride ion adding means for adding a substance that provides chloride ions in a solution to the containing portion, an operation for electrolysis of water to be treated contained in the containing portion of the electrode pair, and Control means for controlling the addition operation of the chloride ion addition means, and the electrode pair is opposed to each of the plurality of anode electrodes and each of the plurality of anode electrodes and alternately with the plurality of anode electrodes. In the electrode pair, both ends of the alternately arranged electrodes are cathode electrodes, and the plurality of anode electrodes and the plurality of cathode electrodes are unitized. And further comprising a lifting electrode supporting member.
[0023]
According to still another aspect of the present invention, management of electrodes included in the electrode pair is facilitated.
[0024]
Thereby, management of a water treatment apparatus becomes easy.
In the water treatment apparatus of the present invention, the ratio of the number of the plurality of cathode electrodes to the number of the plurality of anode electrodes among the electrodes alternately arranged in the electrode pair is 1.1 to 2. 0.0 is preferred.
[0025]
In the water treatment apparatus of the present invention, the area of the surface of the cathode electrode facing the anode electrode is preferably larger than the area of the surface of the anode electrode facing the anode electrode.
[0026]
In the water treatment apparatus of the present invention, the electrode support member supports the cathode electrode on the outer side in the direction intersecting with the direction in which the anode electrode and the cathode electrode are arranged rather than supporting the anode electrode. It is preferable.
[0027]
In the water treatment apparatus of the present invention, it is preferable that the electrode support member includes conductive spacers that keep a predetermined distance from each other while electrically connecting the plurality of cathode electrodes.
[0028]
In the water treatment apparatus of the present invention, it is preferable that the conductive spacer is located outside the anode electrode in a direction intersecting with a direction in which the anode electrode and the cathode electrode are arranged.
[0029]
In the water treatment apparatus of the present invention, it is preferable that the electrode support member can release support of the plurality of cathode electrodes without releasing support of the plurality of anodes.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0031]
[First Embodiment]
1. Overview of nitrogen removal equipment
In FIG. 1, the structure of the water treatment system containing 1st Embodiment of the water treatment apparatus of this invention is shown typically.
[0032]
The water treatment system includes a waste liquid tank 100 that stores waste liquid that has flowed out of a home or factory, and a water treatment device that processes waste liquid (treated water) in the waste liquid tank 100.
[0033]
In the water treatment apparatus, an electrolytic tank 11 is installed in the treated water tank 1. An introduction port 10 is formed in the electrolytic cell 11. Water to be treated is introduced into the electrolytic cell 11 from the waste liquid tank 100 through the pump 91 and the introduction port 10.
[0034]
The electrode pair 2 is immersed in the water to be treated in the electrolytic cell 11. Further, dilute sulfuric acid is introduced into the electrolytic cell 11 from the sulfuric acid tank 81 through the pump 96 and the inlet 10, and saline is supplied from the chloride ion supply tank 82 through the pump 92 and the inlet 10. be introduced.
[0035]
The water to be treated in the electrolytic cell 11 is sent to the nitrogen concentration meter 22 through the discharge port 12, the pump 94, and the electric valve 84, and then returned to the electrolytic cell 11 through the introduction port 10.
[0036]
In addition, the water to be treated in the electrolytic cell 11 is sent to the pH sensor 21 through the discharge port 13, the pump 95, and the electric valve 85.
[0037]
In addition, the water to be treated in the electrolytic cell 11 is sent to the element analyzer 23 through the discharge port 15, the pump 93, and the electric valve 83.
[0038]
Moreover, the water to be treated in the electrolytic cell 11 is discharged to the next treatment facility or the like by appropriately opening and closing a valve provided in the discharge port 14.
[0039]
The gas generated in the electrolytic cell 11 is sent out of the electrolytic cell 11 through the exhaust port 16 when the blower motor 98 is driven.
[0040]
Further, water level sensors 24 and 25 are installed in the electrolytic cell 11 and the chloride ion supply tank 82, respectively, so that the amount of water in each tank is managed.
[0041]
In the electrolytic cell 11, chlorine is generated as will be described later. For this reason, the electrolytic cell 11 is preferably made of a material having chemical resistance to chlorine, such as polyvinyl chloride or reinforced glass fiber.
[0042]
FIG. 2 is a control block diagram of the water treatment apparatus of the present embodiment.
The water treatment apparatus includes a microcomputer and a control circuit 20 that controls the operation of the entire water treatment apparatus.
[0043]
Detection outputs from the pH sensor 21, the nitrogen concentration meter 22, the element analyzer 23, and the water level sensors 24 and 25 are input to the control circuit 20. The control circuit 20 controls the operations of the DC power supply 29, the pumps 91 to 96, the blower motor 98, and the motor operated valves 83 to 85 that supply power to the electrode pair 2 based on these detection outputs.
[0044]
2. Electrode pair structure
FIG. 3 is a front view of the electrode pair 2, and FIG. 4 is a plan view of the electrode pair 2.
[0045]
Referring to FIGS. 3 and 4, electrode pair 2 includes an anode electrode 3 and a cathode electrode 4. The anode electrode 3 is made of, for example, a platinum-ruthenium alloy, or an alloy containing copper or iron, and the cathode electrode 4 is made of, for example, an alloy containing brass or an insoluble substance containing a noble metal (coated with a noble metal). Including other materials). Terminals 30 and 40 are provided above the anode electrode 3 and the cathode electrode 4, respectively. The terminals 30 and 40 are attached to the attachment plate 51 by nuts 55 and 57, respectively. A handle 52 is sandwiched between a nut 56 and a nut 57 and fixed to the mounting plate 51. A mounting plate 53 is installed on the nut 55. The mounting plate 53 is fixed on the mounting plate 51 by being sandwiched between the nut 54 and the nut 55. The attachment plate 53 includes a vertical surface 53A on one side thereof.
[0046]
The anode electrode 3 and the cathode electrode 4 are plate bodies. As shown in FIG. 3, the cathode electrode 4 has a larger dimension in the width direction (in the direction of the double arrow W) than the anode electrode 3. Further, the anode electrode 3 and the cathode electrode 4 are configured such that the areas of the opposing surfaces of the cathode electrode 4 are larger.
[0047]
Further, the cathode electrode 4 and the anode electrode 3 are supported from above by terminals 40 and 30, respectively, by a mounting plate 51, nuts 54 to 57, and a handle 53. The cathode electrode 4 includes a terminal on the outer side in the width direction (in the direction of the double arrow W) than the anode electrode 3, and is supported by the mounting plate 51 or the like at an outer position. The electrode 4 is released from support by the mounting plate 51 and the like by loosening the nut 56 and the nut 57. Therefore, in the present embodiment, the cathode electrode 4 is supported on the mounting plate 51 at a position outside the anode electrode 3, and the anode electrode 3 is removed by loosening the nut 56 and the nut 57. It can be removed and replaced.
[0048]
A plurality of anode electrodes 3 and cathode electrodes 4 are arranged in the depth direction of FIG. FIG. 5 shows a plan view of the anode electrode 3 and the cathode electrode 4 in a state where they are detached from the mounting plate 51. 6A is a front view of the cathode electrode 4, FIG. 6B is a side view of the cathode electrode 4, FIG. 7A is a front view of the anode electrode 3, and FIG. A side view of the anode electrode 3 is shown.
[0049]
With further reference to FIGS. 5 to 7, conductive spacers 41 and 42 are arranged above and below between the cathode electrodes 4 arranged in the direction of the double arrow D in FIG. 5 (the depth direction in FIG. 3). Thus, the plurality of cathode electrodes 4 are fixed at a constant interval. Further, since the spacers 41 and 42 are located outside the anode electrode 3, it is possible to avoid affecting the arrangement of the anode electrodes 3, and the anode electrode 3 and the cathode electrode 4 are energized at this position. To avoid it.
[0050]
When the anode electrode 3 and the cathode electrode 4 shown in FIG. 5 are set as one set, two sets are attached to one attachment plate 51. In the above set, five anodes 3 and six cathode electrodes 4 are unitized. By unitizing in this way, management of the electrode pair 2 becomes easy.
[0051]
In the set shown in FIG. 5, both ends of the alternately arranged electrodes are cathode electrodes 4. As will be described later, in the water treatment apparatus of the present embodiment, the reaction on the cathode electrode 4 is important, and the cathode electrode 4 is considered to be consumed faster than the anode electrode 3.
[0052]
The ratio shown in FIG. 5 and the number of cathode electrodes 4 attached to one attachment plate 51 to the number of anode electrodes 3 is 1.2 in the present embodiment. This ratio should be taken into consideration by the area ratio between the cathode electrode 4 and the anode electrode 3 and the like. However, in order for the reaction in the electrode pair 2 described later to occur efficiently, 1.1 to 2. 0 is preferred. By installing the cathode electrode 4 and the anode electrode 3 at such a ratio, the reduction reaction on the cathode electrode 4 described later can be efficiently advanced.
[0053]
As shown in FIG. 8, the electrode pair 2 configured as described above is fixed to the attachment portion 17 formed on the upper surface of the electrolytic cell 11 by screwing the attachment plate 51 with a screw 50, respectively. It is fixed to the electrolytic cell 11.
[0054]
Here, the positional relationship between the anode electrode 3 and the cathode electrode 4 in the electrode pair 2 will be described with reference to FIG. As described above, the cathode electrodes 4 are held by the spacers 42 so as to ensure a predetermined interval. Since the anode electrode 3 and the cathode electrode 4 are alternately arranged in the electrode pair 2, there is one anode electrode 3 between the two cathode electrodes 4. And the cathode electrode 4 is hold | maintained so that the distance RA with the anode electrode 3 pinched | interposed can be ensured. The distance RA is, for example, about 4 mm. Also, as shown in FIG. 3, the cathode electrode 4 has a dimension larger than the anode electrode 3 by a length RC in the width direction (the direction of the double arrow W). The length RC is about 2 cm, for example. At this time, the anode electrode 3 is fixed so as to be separated from the spacer 42 by a distance RB. The distance RB is, for example, about 1 cm.
[0055]
3. Chemical reaction in electrolytic cell
FIG. 10 schematically shows an electrolytic reaction that is considered to occur when the electrode pair 2 is energized in the electrolytic cell 11.
[0056]
Referring to FIG. 10, the following formulas (1) and (2) are balanced in the water to be treated in the electrolytic cell 11 by adding saline (sodium chloride).
[0057]
H₂O ⇔ H⁺+ OH^-  (1)
NaCl Ｎａ Na⁺+ Cl^-  (2)
Further, in the vicinity of the anode electrode 3, as shown in the equations (3) to (5), oxygen gas is generated by electrolysis of water, chloride ions become chlorine gas, and part of the chlorine gas is hydrated. It becomes hypochlorous acid.
[0058]
2H₂O ⇔ O₂↑ + 4H⁺+ 4e^-  (3)
2Cl^-  Ｃｌ Cl₂↑ + 2e^-  (4)
Cl₂+ H₂O ⇔ H⁺+ Cl^-+ HClO (5)
In the vicinity of the cathode electrode 4, as shown in the equations (6) and (7), hydrogen gas is generated by electrolysis of water, and sodium ions generated at the anode electrode 3 react with hydroxide ions to generate water. Sodium oxide is produced.
[0059]
2H₂O + 2e^-  ⇔ H₂↑ + 2OH^-  (6)
Na⁺+ OH^-  ⇔ NaOH (7)
Thereby, sodium hydroxide is produced in the vicinity of the cathode electrode 4, and the water to be treated becomes alkaline.
[0060]
Then, nitrate ions in the water to be treated introduced into the electrolytic cell 11 are reduced to ammonia via the nitrite ions on the surface of the cathode electrode 4 (see formula (8)) (see formula (9)).
[0061]
NO_Three ^-+ H₂O + 2e^-  ＮＯ NO₂ ^-+ 2OH^-  (8)
NO₂ ^-+ 5H₂O + 6e^-  ＮＨ NH_Three+ 7OH^-  (9)
And hypochlorous acid produced according to said Formula (5) and ammonia produced according to said Formula (9) react according to Formula (10) shown next, and nitrogen gas will arise.
[0062]
2 / 3NH_Three+ HClO → 1 / 3N₂↑ + HCl + H₂O (10)
In the series of electrolytic reactions as described above, if chloride ions are present in the electrolytic cell 11 at an early stage, nitrite ions generated according to the above formula (8) are generated according to the above formula (5). It is oxidized to nitrate ion by chlorous acid. That is, the reverse reaction of the above formula (8) occurs.
[0063]
For this reason, in this Embodiment, the injection | throwing-in of the compound (sodium chloride) which provides the chloride ion to the electrolytic cell 11 is made after predetermined time progress from electrolysis start. In addition, delaying the introduction of the compound that provides chloride ions in this way is particularly easy to oxidize to hypochlorous acid such as chromium, lead, molybdenum, vanadium in the water to be treated introduced into the electrolytic cell 11. This is effective when an element that forms an oxide is contained. Oxidation of such elements with hypochlorous acid has a much faster reaction rate than the oxidation of ammonia in the above formula (10) with hypochlorous acid, so that the nitrite ions generated in the above formula (8) This is because, before being consumed in the formula (9) which is the rate-limiting reaction of the above formulas (8) to (10), it is oxidized to nitrate ions by the reverse reaction of the formula (8). Further, since the oxide of such an element is reduced on the cathode electrode 4, the redox of the element occurs cyclically in the electrolytic cell 11, and even if the amount of the element in the treated water is very small, the hypoxia. This is because chloric acid is consumed by the element.
[0064]
FIG. 11 shows the relationship between the electrolysis time and the amounts of nitrate ions and ammonia nitrogen in the water to be treated in a state where no chloride ions are added. Specifically, FIG. 11 shows the electrolysis time, nitrate ion, and ammonia for water to be treated having a nitrate nitrogen concentration of 2000 mg / L and a chromium concentration of 4-5 mg / L in the absence of chloride ions. It shows the relationship with the amount of reactive nitrogen.
[0065]
Referring to FIG. 11, in the state where chloride ions are not added, the amount of nitrate ions decreases and the amount of ammonia increases with the passage of electrolysis time. In addition, the broken line X shown as a comparison has shown the quantity of ammonia nitrogen at the time of supplying a chloride ion. When chloride ions are added, the decrease amount of nitrate ions and the increase amount of ammonia are remarkably reduced compared to the case where chloride ions are not added. This is because hypochlorous acid is not generated unless chloride ions are added, so that oxidation of chromium by hypochlorous acid does not occur, and the amount of nitrate ions that change to ammonia increases with time and time. Because.
[0066]
In this embodiment, the nitrogen concentration meter 22 detects the amounts of nitrate nitrogen and ammonia nitrogen, and when 1/3 or more of the nitrate nitrogen is converted to ammonia nitrogen (in FIG. 11, the electrolysis time). In “2 hours”), chloride ions (sodium chloride) are introduced into the electrolytic cell 11. This is because the reaction shown in the formula (10) proceeds preferentially because there is much ammoniacal nitrogen.
[0067]
The substance introduced from the chloride ion supply tank 82 may be a compound that supplies chloride ions to the water to be treated, and may be sodium hypochlorite aqueous solution in addition to sodium chloride. Alternatively, hypochlorite ions may be directly generated and supplied to the electrolytic cell 11 by electrolysis or the like in the chloride ion supply tank 82. Moreover, not only a liquid but a solid compound may be supplied from the chloride ion supply tank 82 to the electrolytic cell 11.
[0068]
In addition, as described above, in the control for delaying the introduction of the compound that provides chloride ions into the electrolytic cell 11, the concentration of nitrate nitrogen in the water to be treated introduced into the electrolytic cell 11 is 2000 mg / L or more. It is preferable to be done on condition that the concentration is 1000 milligram / L or more.
[0069]
Furthermore, the above-described control for delaying the introduction of the compound that provides chloride ions into the electrolytic cell 11 is performed by the elemental analyzer 23 using hypochlorous acid such as chromium, lead, molybdenum, and vanadium in the water to be treated. It is preferable that it is made on condition that it is detected that an element that easily oxidizes to form an oxide is contained.
[0070]
4). Control of nitrogen removal equipment when removing nitrogen compounds from treated water
According to the chemical reaction of the above formulas (1) to (10), nitrate ions in the water to be treated introduced into the electrolytic cell 11 are converted into nitrogen gas via ammonia. In addition, according to said chemical reaction, since sodium hydroxide will arise, to-be-processed water will become alkaline. In the present embodiment, the control circuit 20 detects the pH of the water to be treated by the pH sensor 21 and dilute sulfuric acid in the sulfuric acid tank 81 to the electrolytic cell 11 so as to keep the pH of the water to be treated at 5 to 9. And running control to add.
[0071]
[Second Embodiment]
FIG. 12 is a diagram schematically showing a water treatment apparatus according to the second embodiment of the present invention.
[0072]
The water treatment apparatus according to the present embodiment includes a plurality of electrolytic cells including electrolytic cells 61 to 65. In addition, although the water treatment apparatus of this Embodiment is equipped with 12 electrolytic cells, FIG. 12 shows the 5 electrolytic cells 61-65 of some of them for convenience. The electrolytic cell not shown has the same configuration as the electrolytic cells 61 to 65 unless otherwise specified.
[0073]
In the water treatment apparatus of the present embodiment, 12 electrolyzers are arranged in a predetermined order, and the water to be treated discharged from a home or factory is predetermined in the order in which they are arranged in 12 electrolyzers. It is sent every time (for example, 5 minutes) and processed in each electrolytic cell.
[0074]
Each of the electrolyzers 61 to 65 includes various components including DC power supplies 71 to 75, and the control circuit 20 controls the entire water treatment apparatus including the DC power supplies 71 to 75.
[0075]
FIG. 13 is a diagram schematically showing the configuration of the electrolytic cell 61 and its accompanying elements. In addition, all the 12 electrolytic cells included in the water treatment apparatus of the present embodiment have the same configuration.
[0076]
Water to be treated is introduced into the electrolytic bath 61, and the anode electrode 3 and the cathode electrode 4 are provided so as to be immersed in the water to be treated.
[0077]
In addition to the DC power supply 71, the control circuit 20 is connected to a conductivity meter 610 that measures the conductivity of the water to be treated in the electrolytic bath 61, and motorized valves 6111 and 6003.
[0078]
To-be-treated water that has flowed out of the home or factory (or to-be-treated water sent from the previously arranged electrolyzers) is introduced into the electrolyzer 61 through the pump 6001 and the filter 6002. The operation of the pump 6001 is controlled by the control circuit 20.
[0079]
The drug part 6120 stores various drugs such as sulfuric acid and sodium hydroxide for adjusting the pH. The chemical | medical agent in the chemical | medical agent part 61 is suitably introduce | transduced in the electrolytic vessel 61 by the pump 6120 operating. The operation of the pump 6120 is controlled by the control circuit 20.
[0080]
The chloride ion supply tank 611 contains a compound (for example, sodium chloride) or a solution that provides chloride ions to the water to be treated, such as saline. The compound or solution in the chloride ion supply tank 611 is introduced into the electrolytic cell 61 via the motor-operated valve 6111 when the pump 6110 is operated. The operation of the pump 6110 is controlled by the control circuit 20.
[0081]
A thermometer 615 for detecting the temperature of the water to be treated is installed in the electrolytic bath 61. The control circuit 20 receives the temperature detected by the thermometer 615, and controls the value of the current that flows between the anode electrode 3 and the cathode electrode 4 in electrolysis based on the detected temperature.
[0082]
Further, the water to be treated in the electrolytic cell 61 is circulated to the pH sensor 614 and the radiator 613 by driving the pump 6140, and then opened and closed to open the valve 6130 to the electrolytic cell 61. Returned. As described above, by providing a path for cooling the water to be treated in the electrolytic bath 61, even when electrolysis is performed in the electrolytic bath 61 with a high current, an increase in the temperature of the water to be treated can be suppressed. Even if the electrolytic cell 61 is made compact, electrolysis with a high current is possible. The control circuit 20 can control the drive of the pump 6140 and the opening / closing of the valve 6130 based on the temperature detected by the thermometer 615 to determine the amount of water to be circulated to the radiator 613. The radiator 613 is configured by a radiator or the like. Moreover, as shown in FIG. 13, the heat radiator 613 may be connected to each of 12 electrolytic cells, or may be connected to a pipe connecting the 12 electrolytic cells.
[0083]
And the to-be-processed water in the electrolytic vessel 61 is discharged | emitted to the electrolytic cell etc. which were arranged next by the valve 615 being opened after the electrolytic treatment in the electrolytic vessel 61 is completed.
[0084]
In the present embodiment, the voltage between the electrodes (voltage difference between the anode electrode 3 and the cathode electrode 4) is controlled to be 2 to 10V. If the voltage is lower than 2 V, only a voltage lower than the oxidation-reduction potential for the reaction of the above formula (4) is applied. In particular, the chlorine generation efficiency in the anode electrode 3 is significantly reduced, and the above formula ( This is because the reducing ability of nitrate ions in the cathode electrode 4 according to 8) is significantly reduced. When the voltage exceeds 10 V, heat loss in the electrolytic cell 61 increases, the running cost increases, the temperature of the water to be treated in the electrolytic cell 61 increases, and the electrolytic cell 61 is made of polyvinyl chloride or FRP (Fiber Reineforced). This is because it cannot be made of an inexpensive material such as plastic.
[0085]
Here, the heat loss in the electrolytic cell 61 will be specifically described. For example, consider a case where 30 L of water to be treated is treated by electrolysis while the voltage between the electrodes is kept at 3 to 4 V, and the temperature rises by 15 ° C. At this time, it is assumed that 1200 W of power is supplied to the electrode pair including the anode electrode 3 and the cathode electrode 4. At this time, the amount of heat consumed for increasing the water temperature is 30 × 15 = 540 kcal / h = 523 W. That is, the heat loss is 523/1200 × 100 = 44%.
[0086]
The adjustment of the voltage between the electrodes as described above is performed, for example, by introducing an electrolyte or water into the water to be treated in the electrolytic bath 61 based on the detection output of the conductivity meter 610, or by the anode electrode 3 and the cathode electrode. This is done by adjusting the distance of 4. Specifically, when the voltage between the electrodes is less than 2V, the distance between the electrodes is increased, and when it exceeds 10V, the electrolyte or water is added to the water to be treated or the distance between the electrodes is reduced.
[0087]
In the water treatment apparatus of the present embodiment, the capacity of each of the 12 electrolyzers is, for example, 300 L, and the daily treatment amount is 86 m.^ThreeIt is said. In such a water treatment apparatus, when the water to be treated in the electrolytic cell is sent to the next electrolytic cell every 5 minutes, a continuous operation of 60 L / min becomes possible.
[0088]
And in the water treatment apparatus of this Embodiment, for every predetermined time (5 minutes), the to-be-processed water in an electrolytic vessel is discharged after being sent to the electrolytic vessel of a predetermined device ("12") in order. In the apparatus for storing the treated water to be sent to the water treatment apparatus such as the waste liquid tank 100 shown in FIG. 1, the amount of the treated water that must be stored in one machine can be reduced.
[0089]
That is, for example, let us consider a case where the capacity of each of the 12 electrolytic cells is 300 L and the treatment is performed in each electrolytic cell every 5 minutes. In this case, the water to be treated is subjected to an electrolysis process for 60 minutes in an electrolytic cell of “5 minutes × 12”. Moreover, 3600L of to-be-processed water will be processed by "300L * 12" in 1 hour. When this embodiment is not applied and 3600 L of water to be treated is processed in a single electrolyzer, the apparatus for storing the water to be treated requires a capacity of 3600 L. . On the other hand, according to this Embodiment, the capacity | capacitance of the apparatus which stores the above-mentioned to-be-processed water may be 300L. By applying this embodiment, the apparatus for storing the water to be treated for sending to the water treatment apparatus can be made compact.
[0090]
Each embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. Moreover, each embodiment can be implemented independently or in combination.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a water treatment system including a first embodiment of a water treatment apparatus of the present invention.
FIG. 2 is a control block diagram of the water treatment apparatus of FIG.
FIG. 3 is a front view of the electrode pair in FIG. 1;
4 is a plan view of the electrode pair of FIG. 1. FIG.
FIG. 5 is a plan view of the anode electrode and the cathode electrode of the electrode pair of FIG. 1 in a state where they are removed from the mounting plate.
6A is a front view of a cathode electrode of the electrode pair of FIG. 1, and FIG. 6B is a side view thereof.
7A is a front view of an anode electrode of the electrode pair of FIG. 1, and FIG. 7B is a side view thereof.
FIG. 8 is a view for explaining a mode in which an electrode pair is attached to the electrolytic cell in FIG. 1;
9 is a diagram for explaining the positional relationship between an anode electrode and a cathode electrode in the electrode pair in FIG. 1. FIG.
10 is a diagram schematically showing an electrolytic reaction that is considered to occur by energizing an electrode pair in the electrolytic cell of FIG. 1. FIG.
11 is a diagram showing the relationship between the electrolysis time and the amounts of nitrate ions and ammonia nitrogen in the water to be treated in a state where chloride ions are not charged in the electrolytic cell of FIG. 1;
FIG. 12 is a diagram schematically showing a water treatment apparatus according to a second embodiment of the present invention.
13 is a diagram schematically showing the configuration of the electrolytic cell of FIG. 12 and elements associated therewith. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Treated water tank, 2 electrode pair, 3 anode electrode, 4 cathode electrode, 10 inlet, 11, 61-65 electrolysis tank, 12-15 discharge port, 16 exhaust port, 20 control circuit, 21,614 pH sensor, 22 nitrogen Densitometer, 23 Elemental analyzer, 29,71-75 DC power supply, 81 Sulfuric acid tank, 82,611 Chloride ion supply tank, 610 Conductivity meter, 612 Drug part, 613 Radiator, 615 Thermometer.

Claims (16)

A water treatment device for treated water containing nitrogen compounds,
A storage section for storing the water to be treated;
An electrode pair provided in the housing portion;
Chloride ion addition means for adding a substance that provides chloride ions in the solution to the container;
An operation for electrolysis of water to be treated accommodated in the accommodating portion of the electrode pair, and a control means for controlling an addition operation of the chloride ion adding means,
The said control means is a water treatment apparatus which makes the said chloride ion addition means add the substance which provides a chloride ion in the said solution to the said accommodating part after the predetermined time of the electrolysis of the said to-be-processed water by the said electrode pair. The water according to claim 1, wherein the predetermined time after electrolysis of the water to be treated by the electrode pair is a time during which 1/3 or more of all nitrogen compounds contained in the water to be treated become ammoniacal nitrogen. Processing equipment. Compound detection means for detecting whether or not the water to be treated in the container contains a predetermined compound containing chromium, lead, molybdenum, or vanadium,
The control means is configured to add the addition after a predetermined time of electrolysis of the water to be treated by the electrode pair on the condition that the compound detecting means has detected that the water to be treated in the container contains the predetermined compound. The water treatment apparatus according to claim 1, wherein the substance is added to the storage unit. Further comprising nitrate nitrogen concentration detection means for detecting the nitrate nitrogen concentration of the water to be treated in the container,
The control means is provided on the condition that the nitrate nitrogen concentration detecting means detects that the nitrate nitrogen concentration of the water to be treated in the accommodating portion is equal to or higher than a predetermined concentration. The water treatment apparatus according to claim 1, wherein the substance is added to the storage unit by the addition unit after a predetermined time of electrolysis. The water treatment apparatus according to claim 4, wherein the predetermined concentration with respect to the nitrate nitrogen concentration is 2000 mg / liter as the nitrogen concentration. An acidic reagent charging means for charging an acidic reagent into the container;
And further comprising a total nitrogen concentration detection means for detecting the total nitrogen concentration of the water to be treated in the container,
The control means determines the amount of the acidic reagent input by the acidic reagent input means according to at least one of the total nitrogen concentration of the water to be treated in the container, the current value flowing in the electrode pair, and the total nitrogen concentration. The water treatment apparatus according to any one of claims 1 to 5, which is controlled. A water treatment device for treated water containing nitrogen compounds,
A storage section for storing the water to be treated;
An electrode pair provided in the housing portion;
Chloride ion addition means for adding a substance that provides chloride ions in the solution to the container;
An operation for electrolysis of water to be treated accommodated in the accommodating portion of the electrode pair, and a control means for controlling an addition operation of the chloride ion adding means,
The accommodating portion is composed of a plurality of electrolytic cells arranged in a predetermined order,
A connecting pipe that connects the water to be treated between the plurality of electrolytic cells;
A water treatment apparatus further comprising water supply means for sending water to be treated between the plurality of electrolytic cells in the predetermined order. The water treatment apparatus according to claim 7, further comprising heat dissipating means connected to each of the plurality of electrolytic cells or provided in the connection pipe. A temperature detecting means for detecting the temperature of the water to be treated in at least one of the plurality of electrolytic cells;
The water treatment device according to claim 7 or 8, wherein the control unit controls a current value flowing through the electrode pair based on a temperature detected by the temperature detection unit. A water treatment device for treated water containing nitrogen compounds,
A storage section for storing the water to be treated;
An electrode pair provided in the housing portion;
Chloride ion addition means for adding a substance that provides chloride ions in the solution to the container;
An operation for electrolysis of water to be treated accommodated in the accommodating portion of the electrode pair, and a control means for controlling an addition operation of the chloride ion adding means,
The electrode pair includes a plurality of anode electrodes, and a plurality of cathode electrodes facing each of the plurality of anode electrodes and alternately arranged with the plurality of anode electrodes,
In the electrode pair, both ends of the alternately arranged electrodes are cathode electrodes,
The water treatment apparatus further includes an electrode support member that supports the plurality of anode electrodes and the plurality of cathode electrodes as a unit. 11. The ratio of the number of the plurality of cathode electrodes to the number of the plurality of anode electrodes among the electrodes alternately arranged in the electrode pair is 1.1 to 2.0. Water treatment equipment. The water treatment device according to claim 10 or 11, wherein an area of a surface of the cathode electrode facing the anode electrode is larger than an area of a surface of the anode electrode facing the anode electrode. The electrode support member supports the cathode electrode on the outer side in a direction intersecting with the direction in which the anode electrode and the cathode electrode are arranged rather than supporting the anode electrode. The water treatment apparatus according to any one of 12. The water treatment according to any one of claims 10 to 13, wherein the electrode support member includes a conductive spacer that electrically connects the plurality of cathode electrodes and maintains a predetermined distance from each other. apparatus. The water treatment apparatus according to claim 14, wherein the conductive spacer is located outside the anode electrode in a direction intersecting with a direction in which the anode electrode and the cathode electrode are arranged. The water treatment apparatus according to any one of claims 10 to 15, wherein the electrode support member can release support of the plurality of cathode electrodes without releasing support of the plurality of anodes.

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