JP4111896B2 - Water treatment method and water treatment apparatus - Google Patents

Description

  In particular, the present invention makes it possible to use treated water containing organic substances such as sewage including sewage and rainwater as medium water, or to circulate and purify treated water containing organic substances such as pools and public baths. The present invention relates to a water treatment method and a water treatment apparatus.

  A conventional sewage treatment system is composed of a plurality of sewer pipes that collect and flow sewage discharged from households and factories and rain water during rainfall (hereinafter, sewage and rain water are collectively referred to as “sewage”). Combined sewage system, a pump station that relays the sewage collected by the combined sewage system to the treatment plant, and sewage treatment that purifies the transported sewage and discharges it to discharge areas such as rivers and the sea It consists of a field.

  Normally, sewage from households and factories and sewage such as rainwater are sequentially transported to a sewage treatment plant through a sewer pipe, purified at the sewage treatment plant, and then discharged into discharge water areas such as rivers and seas. Is done. However, when there is an abnormal increase in water, such as torrential rain, sewage exceeding the capacity for transporting to a sewage treatment plant due to natural flow in the sewer pipe may flow down. In such a case, since it becomes impossible to transport all the sewage to the sewage treatment plant, a part or all of the sewage is discharged directly into a discharge water area such as a river or the sea. As a result, sewage is discharged directly into discharge water areas such as rivers and seas, and there is a problem that rivers and seas are polluted and public water areas cannot be protected.

  Therefore, conventionally, it has been proposed to perform sewage treatment by performing electrochemical treatment of circulating sewage in a sewer pipe and generating hypohalous acid, ozone, active oxygen, or the like in the sewage. .

  However, in such a case, the electrolytic strength of the electrochemical treatment, that is, the degree of treatment by electrolysis cannot be changed according to the flow rate or quality of sewage, so the electrolytic treatment capacity corresponding to the quality and flow rate of normal sewage When the sewage treatment is carried out in this way, there is a problem that the processing capacity is insufficient when the amount of water deviates from the normal water quality and flow rate or when the sewage in a state polluted from the normal water quality flows into the sewer pipe. On the other hand, if sewage treatment is performed with more electrolytic treatment capacity than necessary on the premise that the flow rate deviates from normal water quality or flow rate or contaminated sewage is treated, the electrolytic treatment capacity becomes excessive and extra running costs arise. There was a problem.

On the other hand, conventionally, an electrolytic ionic water generator that generates ionic water by electrolysis in water to be treated has been developed. These are devices that generate ionic water from tap water by electrolysis, which adjusts the electric field strength according to the amount of water flow and water quality (see Patent Document 1), and the water to be treated supplied to the apparatus. There is one that detects the chloride ion concentration of the liquid and changes the current value used for electrolysis based on this (see Patent Document 2).
Japanese Patent Application Laid-Open No. 5-115576 JP-A-6-126282

  However, conventional ionic water generators are intended for electrolytic treatment of untreated water, such as tap water, and means for detecting changes in water quality and chloride ions. The means for detecting the concentration is detection of water quality in which the target is not contaminated. For this reason, the water quality detection means and chloride ion concentration detection means used in the ion water generator as described above have different measurement target concentration ranges, and circulate in sewage pipes such as sewage from households and factories and rainwater. It cannot be applied to detect water quality in sewage. In particular, since sewage contains a high concentration of organic matter, it has been difficult to detect an accurate degree of contamination.

In the water treatment method according to the first aspect of the present invention, a plurality of pairs of electrodes are immersed in a flow path of the water to be treated, and hypohalous acid, ozone, or active oxygen is generated in the water to be treated to treat the water to be treated. In this case, the energization area to the electrode is controlled based on the flow rate of the water to be treated, and the turbidity of the water to be treated, the chromaticity of the water to be treated, or the concentration of organic substances contained in the water to be treated, or Selected from among the residual chlorine concentration of the treated water, the pH of the treated water, the halide ion concentration of the treated water, the electrical resistance of the treated water, or the conductivity of the treated water. The current density applied to the electrode is controlled based on the quality of the water to be treated.

The water treatment method of the invention of claim 2 is characterized in that, in the above invention, the water to be treated is treated according to the halide ion concentration of the water to be treated, the electrical resistance of the water to be treated, or the conductivity of the water to be treated. Halide ions or substances containing halide ions are added.

According to a third aspect of the present invention, the water treatment method is such that, in each of the above-described inventions, the energized electrodes are switched based on the integrated power amount supplied to the electrodes.

A water treatment device according to a fourth aspect of the present invention is a plurality of pairs of electrodes that are immersed in a flow path of water to be treated and capable of generating hypohalous acid, ozone, or active oxygen in the water to be treated by energization; Flow rate detection means for detecting the flow rate of water, turbidity detection means for detecting the turbidity of the water to be treated, chromaticity detection means for detecting the chromaticity of the water to be treated, or contained in the water to be treated Organic substance detection means for detecting organic substance concentration, residual chlorine detection means for detecting residual chlorine concentration of treated water, pH detecting means for detecting pH of treated water, or halide ion concentration of treated water Water to be treated selected from halide ion detecting means for detecting water, electrical resistance detecting means for detecting electrical resistance of water to be treated, or conductivity detecting means for detecting conductivity of water to be treated Water quality detection means and flow rate detection Controlling the energization area of the electrode based on the output of the stage, and one in which a control means for controlling the current density to be supplied to the electrode on the basis of the output water quality detection means.

The water treatment device of the invention of claim 5 is the halide ion concentration detection means for detecting the halide ion concentration in the water to be treated in the above invention, or the electrical resistance detection means for detecting the electrical resistance of the water to be treated, or Based on the output of the conductivity detection means for detecting the conductivity of the water to be treated and the halide ion concentration detection means, the electrical resistance detection means, or the conductivity detection means, halide ions or halogen in the water to be treated It comprises halide ion addition means for adding a substance containing halide ions.

The water treatment device according to a sixth aspect of the present invention is the water treatment apparatus according to the fourth or fifth aspect, wherein the control means switches the energized electrode based on the integrated power amount supplied to each electrode.

According to the invention of claim 1, in treating the water to be treated by immersing a plurality of pairs of electrodes in the flow path of the water to be treated and generating hypohalous acid or ozone or active oxygen in the water to be treated. The current-carrying area to the electrode is controlled based on the flow rate of the water to be treated, and the turbidity of the water to be treated, the chromaticity of the water to be treated, the concentration of organic substances contained in the water to be treated, or the Residual chlorine concentration of treated water, pH of treated water, halide ion concentration of treated water, electrical resistance of treated water, or conductivity of treated water Since the current density applied to the electrode is controlled based on the quality of the treated water, the degree of electrolysis can be adjusted according to the flow rate of the treated water, the degree of contamination, and the like . As a result, when the flow rate of the water to be treated is small or the water to be treated is relatively clean, the energy saving operation can be performed by reducing the current-carrying area of the electrode to be used or reducing the power supplied to the electrode. Will be able to.

That is, it is possible to control the current-carrying area to a plurality of pairs of electrodes based on the flow rate of the water to be treated and adjust the electrolysis capacity, and in addition to that, the electrodes according to the turbidity of the water to be treated It is possible to adjust the electrolysis capacity by controlling the current density of current supplied to the substrate. Alternatively, if the current density is controlled by the chromaticity of the water to be treated, even when the water to be treated is transparent, it is possible to detect a state in which organic matter or the like is dissolved and colored. It becomes possible to adjust. Alternatively, if the current density is controlled by the concentration of organic matter in the water to be treated, the amount of organic matter contained in the water to be treated, in particular, BOD and COD can be detected. Can be adjusted. Alternatively, if the current density is controlled by the residual chlorine concentration of the water to be treated, it becomes possible to detect chlorate ions and hypochlorite ions in the water to be treated, and based on this, the electrolytic capacity can be adjusted. It becomes. Alternatively, if the current density is controlled by the pH of the water to be treated, the electrolysis capacity can be adjusted according to the pH of the water to be treated. Alternatively, if the current density is controlled by the halide ion concentration of the water to be treated, the electrolysis capacity can be adjusted according to the halide ion concentration in the water to be treated. Alternatively, if the current density is controlled by the electric resistance of the water to be treated, the electrolysis capacity can be adjusted according to the electric resistance of the water to be treated. Alternatively, if the current density is controlled by the conductivity of the water to be treated, the electrolysis capacity can be adjusted according to the conductivity of the water to be treated.

  Thereby, it is possible to accurately grasp the state of the water to be treated, and to determine the electrolysis capacity sufficient for the treatment of the water to be treated based on this, that is, the energization area of the electrode to be used and the power supplied to the electrode. It is possible to perform the treatment of the water to be treated with an electric power amount that is not excessive or insufficient.

According to invention of Claim 2, in the said invention, according to the halide ion density | concentration in a to- be-processed water, an electrical resistance, or electrical conductivity, the said to-be-processed water contains a halide ion or a halide ion. Since the substance is added, the halide ion concentration of the water to be treated can be kept above a certain level, and the concentration of hypochlorous acid generated by the electrochemical treatment can be sufficiently secured. Thereby, the process of to-be-processed water can be implement | achieved effectively.

According to the invention of claim 3, in each of the above inventions, the energized electrode is switched based on the integrated power amount supplied to each electrode, so that a plurality of electrodes can be used on average, and a specific Only the electrodes are used, and it is possible to avoid the disadvantage that the durability is lowered.

According to the water treatment device of the invention of claim 4, a plurality of pairs of electrodes that are immersed in the flow path of the water to be treated and capable of generating hypohalous acid or ozone or active oxygen in the water to be treated by energization; Flow rate detection means for detecting the flow rate of treated water, turbidity detection means for detecting turbidity of treated water, or chromaticity detection means for detecting chromaticity of treated water, or contained in treated water Organic substance detecting means for detecting the concentration of the organic substance to be treated, residual chlorine detecting means for detecting the residual chlorine concentration of the treated water, pH detecting means for detecting the pH of the treated water, or halide of the treated water To-be-treated selected from halide ion detecting means for detecting ion concentration, electric resistance detecting means for detecting electric resistance of to-be-treated water, or conductivity detecting means for detecting the conductivity of to-be-treated water Water quality detection means and flow A control means for controlling the current-carrying area to the electrode based on the output of the detection means and for controlling the current density of the current supplied to the electrode based on the output of the water quality detection means. Based on the output of the water quality detection means, it is possible to adjust the degree of electrolysis according to the flow rate of water to be treated, the degree of contamination, etc., as in the first aspect of the invention.

As a result, when the flow rate of the water to be treated is small or the water to be treated is relatively clean, the energy saving operation can be performed by reducing the current-carrying area of the electrode to be used or reducing the power supplied to the electrode. Will be able to.

That is, the turbidity detecting means for adjusting the energization area of the electrode to be used by the output of the flow rate detecting means for detecting the flow rate of the treated water and detecting the turbidity of the treated water, or the chromaticity of the treated water Chromaticity detection means for detecting water, organic substance detection means for detecting the concentration of organic substances contained in treated water, residual chlorine detection means for detecting residual chlorine concentration in treated water, or pH of treated water PH detecting means for detecting water, halide ion detecting means for detecting halide ion concentration of treated water, electrical resistance detecting means for detecting electric resistance of treated water, or conductivity of treated water Since the current density to the electrode is adjusted by the output of the water quality detection means selected from among the conductivity detection means for detecting the flow rate, the flow rate detection means according to the flow rate of the water to be treated. Electrode conductive surface Controls, it is possible to adjust the electrolyte capacity.

In addition, the turbidity detection means, which is a water quality detection means, can control the current density according to the turbidity of the water to be treated and adjust the electrolysis capacity. Alternatively, if the chromaticity detection means is used, even when the water to be treated is transparent, it is possible to detect the state in which the organic matter is dissolved and colored, and this also makes it possible to adjust the electrolysis capacity. Become. Or, if the organic matter detection means is used, it becomes possible to detect the amount of organic matter contained in the water to be treated, in particular, BOD, COD, etc., and it is possible to adjust the electrolysis capacity according to the amount of the organic matter. Become. Alternatively, if the residual chlorine concentration detection means is used, it becomes possible to detect chlorate ions and hypochlorite ions in the water to be treated, and based on this, it is possible to adjust the electrolysis capacity. Or if a pH detection means is used, it will become possible to adjust electrolysis capability according to pH of to-be-processed water. Alternatively, if the halide ion detection means is used, the electrolysis capacity can be adjusted according to the halide ion concentration in the water to be treated. Or if an electrical resistance detection means is used, it will become possible to adjust electrolysis capability according to the electrical resistance of to-be-processed water. Or if an electrical conductivity detection means is used, it will become possible to adjust electrolysis capability according to the electrical conductivity of to-be-processed water.

  Thereby, it is possible to accurately grasp the state of the water to be treated, and to determine the electrolysis capacity sufficient for the treatment of the water to be treated based on this, that is, the energization area of the electrode to be used and the power supplied to the electrode. It is possible to perform the treatment of the water to be treated with an electric power amount that is not excessive or insufficient.

According to invention of Claim 5, in the said invention, the halide ion concentration detection means which detects the halide ion concentration in to-be-processed water, The electrical resistance detection means to detect the electrical resistance of to-be-processed water, or to-be-processed Conductivity detection means for detecting the conductivity of water, halide ion concentration detection means, or electrical resistance detection means, or based on the output of the conductivity detection means, halide ions or halide ions in the water to be treated As a result, it is possible to keep the halide ion concentration of the water to be treated at a certain level or more, and to sufficiently reduce the concentration of hypochlorous acid generated by the electrochemical treatment. It will be possible to secure. Thereby, the process of to-be-processed water can be implement | achieved effectively.

According to the invention of claim 6, in the invention of claim 4 or claim 5, the control means switches the energized electrodes based on the integrated electric energy supplied to each electrode, so that the plurality of electrodes are averaged. It becomes possible to use it, and only a specific electrode is used, so that the disadvantage that the durability is lowered can be avoided in advance.

  The present invention has been made to solve the conventional technical problems, and it is possible to accurately detect the quality and amount of water to be treated and to perform electrolytic treatment with the electrolytic strength according to the state of the water to be treated. Provided are a water treatment method and a water treatment apparatus. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, sewage such as sewage discharged from each household or factory to be treated in the sewage treatment system or rain water during rain is targeted as treated water.

  FIG. 1 is an explanatory diagram showing an outline of a sewage treatment system S that performs sewage treatment as treated water according to the present embodiment. The sewage treatment system S is a system that performs sewage treatment in a combined sewer 2 constituted by a plurality of sewer pipes 1, and the sewage pipe 1 accommodates both sewage and rainwater. The combined sewer 2 conveys sewage accommodated by a plurality of sewer pipes 1 to the sewage treatment plant 3, and each sewage pipe 1 is buried in the basement with an inclination so that the transport side is gently lowered. Yes. In addition, the sewage from each household or factory, rainwater, etc. are once stored in the sewage 4 or the rainwater 6 and the like, and are allowed to flow down naturally along the inclination of the sewer pipe 1.

  In addition, the sewer pipe 1 is inclined and buried so as to flow naturally toward the sewage treatment plant 3 as described above. However, in flat terrain, the sewer pipe 1 gradually becomes deeper as it flows downstream. The pump station 7 is installed in FIG. This pump station 7 pumps up sewage to near the ground surface by a pumping pump (not shown), and again flows it into the sewer pipe 1 on the downstream side, allowing it to flow naturally, and sequentially transporting it to the sewage treatment plant 3.

  In addition, when the sewage exceeding the capacity in each sewer pipe 1 or the sewage treatment plant 3 flows into the combined sewer 2 at a time when abnormal water increases such as torrential rain, some or all of the sewage pipes 1 An overflow channel 9 is provided for discharging directly into a discharge water area 8 such as a river or the sea as flowing water. Normally, this overflow channel 9 is provided with an overflow weir (not shown) at a location intersecting with each sewer pipe 1, and the overflow river 9 receives the sewage overflowing from the upper part of the sewer pipe 1 in the overflow weir. It is made possible to discharge into the discharge water area 8 from the discharge port 20 provided on the discharge water area 8 side such as a river. The overflow channel 9 is also provided in the pump station 7, and this also allows the overflow water during abnormal times to be discharged directly into the discharge water area 8, thereby preventing the occurrence of disasters such as inundation. .

  The sewage treatment plant 3 is a facility for purifying the sewage that is accommodated in the combined sewer 2 constituted by a plurality of sewage pipes 1, and will be described in detail later in the sewage treatment plant 3 in this embodiment. The purification process is performed by an electrochemical method (electrolysis) using a plurality of electrodes for electrolysis, but besides this, various kinds of activated sludge tanks and sedimentation tanks, biological tanks (not shown), aeration tanks, chlorine contact tanks, etc. Purifying facilities are provided, and by passing through these facilities, sewage is purified and discharged into a discharge water area 8 such as a river or the sea through a drain pipe 10.

  On the other hand, in the sewer pipe 1, electrolysis electrodes 11 and 12 as processing means as shown in FIG. 2 are provided. The electrodes 11 and 12 for electrolysis are arranged correspondingly so that at least a part of the electrodes 11 and 12 is immersed in sewage, and a power source 13 (described later) for energizing the electrodes 11 and 12 is connected thereto. The power supply 13 is connected to a control device 14 for controlling the potential of the energizing electrodes to the electrodes 11 and 12.

  Further, in order to further extend the residence time of the sewage in the sewer pipe 1 and improve the treatment capacity, the electrolytic tank 15 is formed outside the sewer pipe 1 as shown in FIG. Electrolysis electrodes 11 and 12 are provided in the electrolytic cell 15. Here, an example in which the electrodes 11 and 12 for electrolysis are provided in the electrolytic cell 15 will be described with reference to FIG. FIG. 4 is a view for explaining electrolysis electrodes provided in the electrolytic cell 15 and energization control to these electrodes.

  In this embodiment, three pairs of electrolysis electrodes 11A, 12A, 11B, 12B, 11C, and 12C are provided in the electrolytic cell 15, and these are connected to the power supply circuit via the changeover switches 15A, 15B, and 15C, respectively. (Power supply) Connected to 13A, 13B, 13C. In addition, in the sewer pipe 1 located on the upstream side of the electrolytic cell 15, as a means for detecting the state of sewage, in this embodiment, a flow rate sensor (flow rate detection means) 16 for detecting the flow rate of sewage, A turbidity sensor (turbidity detecting means) 17 for detecting the turbidity of sewage is provided. The flow rate sensor 16 and the turbidity sensor 17 are connected to the input side of the control device 14, and the output side of the control device 14 includes power supply circuits 13A, 13B, 13C and changeover switches 15A, 15B, 15C. It is connected. It is assumed that the power supply circuits 13A, 13B, and 13C can adjust the current values that flow independently according to the output of the control device 14, respectively. It is also assumed that a power source 13 for supplying power to the electrolysis electrodes 11 and 12 disposed in the sewer pipe 1 is connected to the control device 14.

  In this embodiment, the electrodes 11, 12, 11 A, 12 A, 11 B, 12 B, 11 C and 12 C are coated with a noble metal electrode such as platinum (Pt) or a mixture of platinum and iridium (Ir), or these. It is composed of an insoluble conductor. In addition, the electrode for electrolysis as described above is a carbon-based conductor or a conductor coated with the carbon-based conductor, a ceramic-based conductor containing ferrite, or a conductor coated with the ceramic-based conductor, Alternatively, it may be made of an iron alloy such as stainless steel or a conductor coated with the iron alloy.

  The operation of this embodiment will be described with the above configuration. In the combined sewer 2 in the present embodiment, sewage discharged from each home or factory, rainwater, and the like are temporarily stored in the sewage 4 or stormwater 6. The stored sewage and rainwater flow down into the sewer pipe 1 respectively, and naturally flow down along the slope in the sewer pipe 1 as sewage.

  Here, since the electrodes 11 and 12 for electrolysis are provided in the sewer pipe 1 as described above, the power source 13 is supplied to the electrodes 11 and 12 for electrolysis periodically or continuously by the control device 14 as necessary. The sewage flowing down in the sewer pipe 1 by being supplied with electricity is subjected to electrochemical treatment by the electrodes 11 and 12 for electrolysis, that is, in this embodiment, electrolytic treatment.

In the electrolytic treatment, the control device 14 turns on the power supply 13 to apply a positive potential to the electrode 11 and a negative potential to the electrode 12. The electrode 11 becomes an anode and the electrode 12 becomes a cathode. By applying such a potential, organic substances contained in sewage (especially sewage) are decomposed into nitrate ions as nitrate nitrogen, ammonia and ammonium ions as ammonia nitrogen, carbon dioxide and water, etc. (Reaction A) . Reaction A is shown below.
Reaction A Organic matter → NO ₃ ⁻ + NH ₃ + CO ₂ + H ₂ O

  Thereby, the organic matter in the sewage (sewage) can be efficiently converted into nitrate nitrogen and ammonia nitrogen.

Then, on the electrolysis electrode 11 side constituting the anode, chloride ions contained in the sewage discharge electrons to generate chlorine (reaction B). This chlorine dissolves in water to produce hypochlorous acid as hypohalous acid (reaction C). The produced hypochlorous acid reacts with ammonia (ammonium ions) produced in the sewage in the above-mentioned reaction A, undergoes a plurality of chemical changes, and is converted to nitrogen gas (reaction D). Hereinafter, Reaction B to Reaction D are shown. At the same time, ozone or active oxygen is also generated.
Reaction B NaCl → Na ⁺ + Cl ⁻
2Cl ⁻ → Cl ₂ + 2e ⁻
Reaction C Cl ₂ + H ₂ O → HClO + HCl
Reaction D NH ₃ + HClO → NH ₂ Cl + H ₂ O
NH ₂ Cl + HClO → NHCl ₂ + H ₂ O
NH ₂ Cl + NHCl ₂ → N ₂ ↑ + 3HCl

Further, ammonia (ammonium ions) in the sewage reacts with ozone generated on the electrolysis electrode 11 side constituting the anode or active oxygen as shown in the reaction E, and this is also denitrified into nitrogen gas. .
Reaction E 2 NH ₃ (aq) +3 (O) → N ₂ ↑ + 3H ₂ O

  Thereby, it becomes possible to treat the organic matter contained in the sewage to nitrogen gas through nitrate nitrogen, nitrite nitrogen and ammonia nitrogen. Further, in the vicinity of the electrode 11 for electrolysis constituting the anode, chlorine or hypochlorous acid is generated as described above, so that microorganisms such as Escherichia coli existing in the sewage that passes in the vicinity of the electrode 11 for electrolysis are present. Sterilization becomes possible.

  In addition, according to the present embodiment, it becomes possible to treat sewage with hypohalous acid, ozone or active oxygen immediately after being generated by electrolysis, and thereby a significantly high sterilizing effect can be obtained. . Furthermore, since the sewage is sterilized by an electrochemical method without using chemicals, it can reduce environmental damage.

  Furthermore, since organic substances contained in sewage and pollutants such as Escherichia coli can be processed without injecting chemicals such as special disinfectants into the sewage, storage for storing disinfectants and other chemicals A facility becomes unnecessary, and the danger caused by the storage of the medicine can be avoided.

  On the other hand, as shown in FIG. 4, the electrodes 11A, 12A, 11B, 12B, 11C and 12C for electrolysis disposed in the electrolytic tank 15 provided in the sewer pipe 1 are connected to the power supply circuits 13A, 13B, By controlling 13C, a positive potential is applied to the energized electrodes 11A, 11B and / or 11C, a negative potential is applied to the electrodes 12A, 12B and / or 12C, and the electrodes 11A, 11B and / or 11C become anodes. The electrodes 12A, 12B and / or 12C serve as cathodes.

  Thereby, like the electrodes 11 and 12 for electrolysis arrange | positioned at the said sewer pipe 1, the organic substance contained in a sewage (especially sewage) is ammonia as ammonium nitrate, ammonium ion as nitrate nitrogen, or ammonia nitrogen. It is decomposed into ions or carbon dioxide and water (reaction A). Also by this, the organic substance in sewage (sewage) can be efficiently converted into nitrate nitrogen and ammonia nitrogen.

  In addition, on the electrode side for electrolysis constituting the anode, chloride ions contained in the sewage release electrons to generate chlorine (reaction B), and the chlorine dissolves in water to form hypohalous acid. To produce hypochlorous acid (reaction C). Furthermore, the produced hypochlorous acid reacts with ammonia (ammonium ions) produced in the sewage in the above-mentioned reaction A, undergoes a plurality of chemical changes, and is then converted into nitrogen gas (reaction D). . Then, ammonia (ammonium ions) in the sewage reacts with ozone or active oxygen generated on the electrolysis electrode constituting the anode as shown in the reaction E, and is denitrified into nitrogen gas by this reaction. .

  Thereby, it becomes possible to treat the organic matter contained in the sewage to nitrogen gas through nitrate nitrogen, nitrite nitrogen and ammonia nitrogen. Further, in the vicinity of the electrode 11 for electrolysis constituting the anode, chlorine or hypochlorous acid is generated as described above, thereby sterilizing microorganisms such as Escherichia coli in the sewage passing through the vicinity of the electrode 11 for electrolysis. It becomes possible.

  In this embodiment, based on the outputs of the flow rate sensor 16 and the turbidity sensor 17 installed in the sewer pipe 1 located on the upstream side of the electrolytic cell 15, the control device 14 controls the changeover switches 15A, 15B, 15C. The ON / OFF control is performed, and the current value of the power supply circuits 13A, 13B and / or 13C in which the changeover switches 15A, 15B, and 15C are turned on is controlled.

  Specifically, when the flow rate of sewage detected by the flow rate sensor 16 is higher than the preset maximum flow rate value, the control device 14 turns on all the changeover switches 15A, 15B, and 15C, If it is less than the preset minimum flow rate value, any one of the changeover switches 15A, 15B or 15C is turned ON. When the flow rate of the sewage detected by the flow rate sensor 16 is not less than the minimum flow rate value and not more than the maximum flow rate value, the control device turns on any two changeover switches 15A, 15B or 15C. To do.

  Further, when the turbidity of the sewage detected by the turbidity sensor 17 is higher than a predetermined turbidity, the control device 14 is a power supply circuit that is turned ON among the changeover switches 15A, 15B, or 15C. By increasing the current intensity of 13A, 13B or 13C and increasing the current density on the electrolytic electrodes 11A, 12A or 11B, 12B or 11C, 12C, the amount of hypochlorous acid produced in the sewage is increased. Plan. On the other hand, when the turbidity of the sewage detected by the turbidity sensor 17 is lower than the predetermined turbidity, the control device 14 is a power supply circuit that is turned ON among the changeover switches 15A, 15B, or 15C. Decreasing the current intensity of 13A, 13B or 13C and lowering the current density on the electrolytic electrodes 11A, 12A or 11B, 12B or 11C, 12C reduces the amount of hypochlorous acid produced in the sewage. Plan.

  Thereby, according to the state of the sewage before performing the electrochemical treatment in the electrolytic cell 15, the number of electrodes for electrolysis to be energized, the power supplied to the electrodes for electrolysis, in this embodiment, the current density is controlled. Thus, it is possible to adjust the degree of electrolysis and the electrolysis capacity in accordance with the flow rate and pollution degree of sewage. Therefore, when the flow rate of sewage is low or when the sewage is relatively clean, the consumption of excess power can be suppressed by reducing the number of electrodes used for electrolysis or reducing the power supplied to the electrodes for electrolysis. And energy saving operation can be executed. In addition, the amount of residual chlorine released can be suppressed.

  In this embodiment, each power supply circuit 13A, 13B, or 13C is provided with a changeover switch 15A, 15B, or 15C and a pair of electrolysis electrodes 11A, 12A, or 11B, 12B, or 11C, 12C. In addition to this, as shown in FIG. 5, selector switches 15A, 15B and 15C are connected in parallel to the power supply circuit 13 which can change the current value based on the control device 14, and each selector switch 15A, The electrodes 11A and 12A for electrolysis corresponding to 15B and 15C, or 11B and 12B, or 11C and 12C may be connected.

  In this embodiment, the area of the current-carrying electrode can be adjusted by the number of electrodes for electrolysis to be energized. However, in practice, any other method can be used as long as the area of the electrode to be energized can be adjusted. Even so, the same effect is obtained.

  In this embodiment, the state of sewage is detected by the flow sensor 16 and the turbidity sensor 17, and the number of electrodes for electrolysis and the current density used by the control device 14 are adjusted based on these detection results. The electrolysis capacity can be changed according to the flow rate and the degree of contamination. In this embodiment, both the flow sensor 16 and the turbidity sensor 17 are used as means for grasping the state of sewage. However, in addition to this, only the flow sensor 16 is provided as shown in FIG. The flow rate of sewage flowing through 1 is detected, and based on this, the number of electrodes for electrolysis to be used (or the area of the current-carrying electrodes) may be changed. Furthermore, as shown in FIG. 7, only the turbidity sensor 17 may be provided to detect the turbidity of sewage flowing through the sewer pipe 1, and based on this, the current density to be energized may be changed.

  In addition to the above, as means for detecting the state of sewage, a chromaticity sensor for detecting chromaticity of sewage, an organic substance sensor for detecting the concentration of organic substances contained in sewage, for example, BOD and COD, and residual in sewage Residual chlorine concentration sensor that detects chlorine concentration, pH sensor that detects pH of sewage, halide ion concentration sensor that detects halide ion concentration in sewage, electrical resistance measurement device that detects electrical resistance of sewage, conductivity of sewage A conductivity measuring device that detects the rate may be used. These detection means may be used in place of the flow rate sensor 16 and the turbidity sensor 17, and besides this, the flow rate sensor 16 and / or the turbidity sensor 17 and any one of the detection means described above, A combination of these may be used.

  Thus, the chromaticity sensor can detect a state in which organic matter or the like is dissolved and colored even in sewage having low turbidity and almost transparent. When the density is increased and the chromaticity is low, the current density can be decreased. In addition, the organic matter sensor can detect the amount of organic matter contained in the sewage, especially BOD and COD. When the amount of the organic matter is a predetermined amount or more, for example, the current density is increased as the electrolytic capacity. If it is less than the predetermined amount, the current density can be reduced.

  Furthermore, the residual chlorine concentration sensor can directly detect chlorate ions and hypochlorite ions in sewage, and based on this, the residual chlorate ions and hypochlorite ions can be detected in a predetermined amount or more. In some cases, it is not necessary to generate chlorate ions or hypochlorite ions in the sewage more than necessary, so that the current density can be reduced as the electrolytic capacity. On the other hand, if the amount of chlorate ion or hypochlorite ion remaining in the sewage is less than the specified amount, there is insufficient chlorate ion or hypochlorite ion for treating the sewage, so the electrolytic capacity As a result, the current density can be increased.

  In addition, the pH sensor can detect the pH of the sewage, and based on this, when the pH of the sewage is alkaline, the current density can be increased as the electrolysis capacity in order to increase the sterilizing power. It becomes possible.

  The halide ion concentration sensor makes it possible to adjust the electrolysis capacity in accordance with the halide ion concentration. With the electrical resistance measuring device, the electrolysis capacity can be adjusted according to the electrical resistance of the sewage. Furthermore, it becomes possible to adjust electrolysis capability according to the electrical conductivity of a sewage with an electrical conductivity measuring apparatus.

  As a result, the state of sewage can be accurately grasped, and based on this, the electrolysis capacity sufficient to satisfy the treatment of sewage, that is, the number of electrodes to be used or the energization area and the power supplied to the electrodes can be determined. It becomes possible to perform the treatment of the water to be treated with the amount of electric power without excess or deficiency.

  In addition, the control apparatus 14 is provided with the time limit means and the memory | storage means, and shall integrate | accumulate the time and electric current value which each electrode 11A, 12A, 11B, 12B, 11C or 12C was supplied with electricity. Then, based on the integrated value, the electrodes 11A, 12A, 11B to be used so as to equalize the time and current value to be energized to each electrode 11A, 12A, 11B, 12B, 11C or 12C, that is, the integrated power. , 12B, 11C, or 12C are selected to control the selector switches 15A, 15B, and 15C.

  Thereby, it becomes possible to use a plurality of electrodes 11A, 12A, 11B, 12B, 11C or 12C on average, and only a specific electrode is used, thereby avoiding the disadvantage that the durability is lowered. become able to.

  Further, in addition to the above embodiment, a chloride ion concentration sensor (halide ion concentration detecting means) is provided in the sewer pipe 1, and the chloride ion concentration of the sewage in the sewer pipe 1 is detected. In addition, halide ions or substances containing halide ions, such as sodium chloride, may be added. As a result, the chloride ion concentration of the sewage can be kept above a certain level, and the concentration of hypochlorous acid generated by the electrochemical treatment can be sufficiently secured. This makes it possible to effectively achieve sewage treatment. In addition, it replaces with a chloride ion concentration sensor (halide ion concentration detection means), and even if it is an electrical resistance measuring device and a conductivity measuring device, the same effect shall be show | played.

  In the sewer pipe 1 and the electrolytic cell 15 as described above, the sewage is downstream after sufficiently treating or treating organic substances in the sewage and pollutants such as Escherichia coli by electrolytic treatment as an electrochemical method. It is conveyed to the sewage treatment plant 3 through the sewer pipe 1 and the pump station 7. Then, again, after being purified at the sewage treatment plant 3, it can be discharged into the discharge water area 8 through the drain pipe 10. Thereby, since the sewage after processing in the sewer pipe 1 in advance is conveyed to the sewage treatment plant 3, the purification treatment burden in the sewage treatment plant 3 is reduced, and the sewage treatment can be performed efficiently. Become.

  In the above embodiment, the detection of the state of sewage is performed upstream of the electrolytic cell 15, that is, before the treatment in the electrolytic cell 15, but a detection means is disposed downstream of the electrolytic cell 15, Based on the detection, the electrolytic capacity, that is, the number of electrodes to be used or the energization area and the power supplied to the electrodes may be controlled in a feedback manner. In addition, the state of the sewage may be detected both before and after the treatment in the upstream and downstream sides of the electrolytic cell 15, that is, in the electrolytic cell 15, and the electrolytic capacity may be controlled based on this. In such a case, it becomes possible to grasp the state of the sewage more accurately, and it is possible to control the electrolysis ability with precision.

  In this embodiment, sewage is used as the water to be treated, but in addition to this, rainwater, pool water, hot spring water, large-scale bath drainage, industrial wastewater, household wastewater, etc. are used as middle water after treatment. The same effect can be obtained by using the one that can be used. Furthermore, the same effect can be obtained by applying the present invention to means for circulating and purifying water to be treated containing organic substances such as a pool and a public bath, other than those used as intermediate water after treatment.

It is an outline explanatory view of a sewage treatment system. It is explanatory drawing which shows the outline | summary in the sewer pipe of the sewage treatment system of FIG. It is explanatory drawing which shows the outline | summary in a sewer pipe provided with the electrolytic vessel. It is a figure explaining the electrode for electrolysis provided in an electrolytic vessel, and energization control to these electrodes. It is a figure explaining the electricity supply control to each electrode of another Example. It is a figure explaining the electricity supply control to each electrode of another other Example. It is a figure explaining the electricity supply control to each electrode of another another Example.

Explanation of symbols

S Sewage treatment system 1 Sewer pipe 2 Combined sewer 3 Sewage treatment plant 4 Sewage 6 Rainwater 7 Pump station 8 Discharge water area 9 Overflow channel 10 Drain pipe 11, 12, 11A, 12A, 11B, 12B, 11C, 12C Electrolysis Electrodes 13, 13A, 13B, 13C Power supply circuit (power supply)
14 control device 15A, 15B, 15C changeover switch 16 flow rate sensor 17 turbidity sensor 20 outlet

Claims (6)

In the water treatment method of treating the treated water by immersing a plurality of pairs of electrodes in the treated water flow path and generating hypohalous acid, ozone, or active oxygen in the treated water,
Controlling the energization area to the electrode based on the flow rate of the water to be treated; and
Turbidity of the treated water, chromaticity of the treated water, concentration of organic matter contained in the treated water, residual chlorine concentration of the treated water, or pH of the treated water Or, based on the water quality of the treated water selected from the halide ion concentration of the treated water, the electrical resistance of the treated water, or the conductivity of the treated water. A water treatment method characterized by controlling a current density to be energized . A substance containing halide ions or halide ions in the water to be treated according to the halide ion concentration of the water to be treated, the electrical resistance of the water to be treated, or the conductivity of the water to be treated. The water treatment method according to claim 1, wherein: The water treatment method according to claim 1 or 2, wherein the energizing electrode is switched based on an integrated power amount supplied to each electrode . A plurality of pairs of electrodes immersed in a flow path of the water to be treated and capable of generating hypohalous acid or ozone or active oxygen in the water to be treated by energization;
Flow rate detecting means for detecting the flow rate of the water to be treated;
Turbidity detecting means for detecting the turbidity of the treated water, chromaticity detecting means for detecting the chromaticity of the treated water, or organic substance detecting means for detecting the concentration of organic matter contained in the treated water Or a residual chlorine detecting means for detecting the residual chlorine concentration of the treated water, a pH detecting means for detecting the pH of the treated water, or a halide for detecting a halide ion concentration of the treated water. Water quality detection of the treated water selected from ion detection means, electrical resistance detecting means for detecting electrical resistance of the treated water, or conductivity detecting means for detecting conductivity of the treated water Means,
Controlling the energization area to the electrode based on the output of the flow rate detection means; and
A water treatment apparatus comprising: control means for controlling a current density applied to the electrode based on an output of the water quality detection means. Halide ion concentration detecting means for detecting halide ion concentration in the treated water, electric resistance detecting means for detecting electric resistance of the treated water, or conductivity for detecting conductivity of the treated water Based on the output of the detection means, the halide ion concentration detection means, the electrical resistance detection means, or the conductivity detection means, a halide ion or a substance containing halide ions is added to the treated water The water treatment apparatus according to claim 4, further comprising halide ion adding means . The water treatment apparatus according to claim 4 or 5, wherein the control means switches the energized electrodes based on an integrated power amount supplied to the electrodes .

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