JP2012254427A - Apparatus for cleaning underground water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean underground water under a reducing atmosphere containing ammonium nitrogen, ferric iron, and manganese ion while suppressing a supplying quantity of hypochlorous ion.SOLUTION: An apparatus 1 for cleaning the underground water includes: a water taking channel 10 for pumping up the underground water; a cation exchanging device 20 directly connected to the water taking channel 10 and for obtaining treated water by treating the underground water by cation exchanging bodies; a water sending channel 30 for sending the treated water; a chemical agent feeding device 50 arranged in the water sending channel 30 and for feeding hypochlorous acid aqueous solution to the treated water; a measuring device 60 arranged downstream of the chemical agent feeding device 50 in the water sending channel 30 and for measuring the hypochlorous ion concentration of the treated water; a regenerating device 40 for regenerating the cation exchanging bodies of the cation exchanging device 20; and a control device 70 for operating the regenerating device 40 when the measuring result in the measuring device 60 lowers below a reference value set in advance.

Description

  The present invention relates to a water purification device, and more particularly to a groundwater purification device.

Since groundwater contains ammoniacal nitrogen (ammonium ions), organic substances such as microorganisms, iron and manganese, purification treatment is performed to remove these components when used as drinking water. Since groundwater pumped from the ground is usually in an oxygen-free reducing atmosphere, both iron and manganese contained therein are dissolved in the form of divalent ions (Fe ²⁺ and Mn ²⁺ ). is doing.

  In general groundwater purification treatment, for example, as described in Patent Document 1, after supplying hypochlorite ions by injecting an aqueous sodium hypochlorite solution into groundwater pumped from the ground This groundwater is treated with iron removal and manganese removal equipment. A general iron removal / manganese removal apparatus used here is a filtration apparatus using anthracite and manganese sand (catalyst sand carrying hydrated manganese dioxide) as a filter medium.

  In this purification treatment, groundwater is sterilized by oxidizing organic substances with the supplied hypochlorite ions. Ammonia nitrogen contained in the groundwater is also oxidized by the supplied hypochlorite ions to be converted into nitrogen and volatilized, and removed from the groundwater. Furthermore, each divalent ion of iron and manganese contained in the groundwater is oxidized by the supplied hypochlorite ion to become a trivalent ion, and is precipitated in the groundwater as a hydroxide. It is removed from groundwater by filtration with iron removal and manganese removal equipment.

  In this purification treatment, hypochlorite ions simultaneously sterilize, oxidize ammoniacal nitrogen and oxidize iron and manganese, so a large amount of hypochlorite ions is supplied to the pumped groundwater. There is a need. In particular, since hypochlorite ions are easily consumed by reaction with ammoniacal nitrogen, hypochlorite ions are considered in consideration of such circumstances in order to promote sterilization and oxidation of iron and manganese smoothly. It is necessary to set a large amount of supply. However, if humic substances such as humic substances are contained in groundwater, harmful substances such as trihalomethane are by-produced as the amount of hypochlorite ions supplied increases. This process is required.

JP-A-2005-95812

  An object of the present invention is to purify groundwater while suppressing the supply amount of hypochlorite ions.

  The present invention relates to a groundwater purification apparatus, which is directly connected to a water intake path for pumping groundwater in a reducing atmosphere containing ammoniacal nitrogen, iron ions and manganese ions from the ground, and the water intake path. In addition, a cation exchange device for obtaining treated water by treating groundwater from the water intake route with a cation exchanger, a water supply route for supplying treated water from the cation exchange device, and a water supply route are provided. A supply device for supplying hypochlorite ions to the treated water, and a measuring device for measuring the concentration of hypochlorite ions in the treated water provided on the downstream side of the supply device in the water supply path; And a regenerator for regenerating the cation exchanger, and a control device for operating the regenerator when the measurement result of the measurement apparatus falls below a preset reference value.

  The present invention according to another aspect relates to a method for purifying groundwater. This method uses a cation exchanger for groundwater in a reducing atmosphere pumped from the ground and containing ammonia nitrogen, iron ions, and manganese ions. A step of obtaining treated water by treating with, a step of supplying hypochlorite ions to the treated water, a step of measuring a hypochlorite ion concentration of treated water supplied with hypochlorite ions, And regenerating the cation exchanger when the hypochlorite ion concentration falls below a preset reference value.

  Furthermore, the present invention according to another aspect provides treated water by treating water in a reducing atmosphere containing ammoniacal nitrogen, iron ions and manganese ions with a cation exchanger, and the obtained treated water contains hypochlorous acid. The present invention relates to a method for detecting breakthrough of a cation exchanger in the case of preparing purified water by supplying acid ions, and this detection method relates to treated water supplied with hypochlorite ions. A step of measuring a hypochlorite ion concentration and a step of determining whether or not the hypochlorite ion concentration has decreased below a preset reference value.

  The apparatus and method for purifying groundwater according to the present invention supplies hypochlorite ions after treating the groundwater in a reducing atmosphere with a cation exchanger, and therefore suppresses the amount of hypochlorite ions supplied. As a result, it is possible to purify groundwater while suppressing the generation of harmful substances such as trihalomethane.

  The cation exchanger breakthrough detection method according to the present invention focuses on the hypochlorite ion concentration of the treated water obtained by the treatment with the cation exchanger. It can be easily detected.

The schematic diagram of the purification device concerning one embodiment of the present invention. The operation | movement flowchart of the said purification apparatus.

  With reference to FIG. 1, the purification apparatus of the groundwater which concerns on one Embodiment of this invention is demonstrated. Groundwater to be purified by this purification device contains ammonia nitrogen (ammonium ions), organic matter such as microorganisms, iron and manganese, and in particular, iron and manganese are each divalent in an oxygen-free reducing atmosphere. These are included as iron ions and divalent manganese ions.

  In FIG. 1, the purification apparatus 1 mainly includes a water intake path 10, a cation exchange apparatus 20, a water supply path 30, a regeneration apparatus 40, a medicine supply apparatus 50, a measurement apparatus 60, and a control apparatus 70.

  The intake channel 10 has a pump 11 for pumping up groundwater, and one end extends to a water source such as a well or an underground aquifer.

  The cation exchange device 20 has two units, a first unit 21 and a second unit 22, each filled with a cation exchanger. The water intake path 10 branches into two paths, a first path 10 a and a second path 10 b, through the first switching valve 23 in the cation exchanger 20. The first path 10 a is directly connected to the first unit 21. Further, the second path 10 b is directly connected to the second unit 22. Details of the first switching valve 23 will be described later.

  As described above, since the intake path 10 is directly connected to the first unit 21 and the second unit 22 through the first path 10a and the second path 10b, the groundwater pumped by the intake path 10 is The oxygen-free reducing atmosphere can be maintained until the first unit 21 and the second unit 22 are supplied.

  The cation exchanger filled in each of the first unit 21 and the second unit 22 is a strong acidic cation exchanger of Na type, K type or H type or a weak acidic cation of Na type, K type or H type. It is an exchanger and is usually made of a granular or fibrous resin. Here, when removing the hardness components (calcium ions and magnesium ions) contained in the groundwater at the time of purification, a strong acid cation exchanger, in particular, a Na-type or K-type strong acid cation exchanger is used. Is preferred.

  The water supply path 30 is for supplying the treated water from the cation exchange device 20, and ends in a water storage tank (not shown) or a water supply path (not shown) for temporarily storing the treated water. The main path 31 is in communication with the main path 31 and branches into two paths, a first water supply path 32 and a second water supply path 33 in the cation exchange device 20. The 1st water supply path 32 is connected to the exit side of the 1st unit 21, and has the 2nd change-over valve 32a. The second switching valve 32a communicates with the first drain path 34, and is for switching the flow path of treated water from the first unit 21 to either the main path 31 or the first drain path 34. . The second water supply passage 33 communicates with the outlet side of the second unit 22 and has a third switching valve 33a. The third switching valve 33a communicates with the second drain path 35, and is for switching the flow path of treated water from the second unit 22 to either the main path 31 or the second drain path 35. . Note that the first drain path 34 and the second drain path 35 merge to form a single disposal path 36.

  The regeneration device 40 is for regenerating the ion exchange capacity of the cation exchanger filled in the first unit 21 or the second unit 22 of the cation exchange device 20, and includes a supply unit 41, a supply path 42, and the like. have. The supply unit 41 is for supplying a regenerant solution for regenerating the cation exchanger to the first unit 21 or the second unit 22 through the supply path 42. The regenerant solution used here is selected according to the type of cation exchanger. In the case of using a Na-type cation exchanger, for example, a sodium chloride aqueous solution is used. Moreover, when using a K-type cation exchanger, potassium chloride aqueous solution is used, for example. Further, when an H-type cation exchanger is used, for example, an aqueous hydrochloric acid solution is used.

The supply path 42 communicates with the first switching valve 23. The first switching valve 23 is a four-way valve, and a flow path can be set in one of the following two forms.
<First form>
The intake route 10 and the first route 10a are connected, and the supply route 42 and the second route 10b are connected.
<Second form>
The intake route 10 and the second route 10b are connected, and the supply route 42 and the first route 10a are connected.

  The chemical supply device 50 is for supplying hypochlorite ions to the treated water from the cation exchange device 20, and more specifically, sodium hypochlorite and secondary sodium chloride to the treated water. This is for supplying a hypochlorite such as potassium chlorite or an aqueous solution of hypochlorous acid (hereinafter sometimes referred to as “drug aqueous solution”). The chemical supply device 50 communicates with the water supply path 30 and is set so as to control the supply amount of the chemical aqueous solution to the treated water.

  The measuring device 60 is disposed on the downstream side of the drug supply device 50 in the water supply path 30 and is used for measuring the hypochlorite ion concentration in the treated water supplied with the drug aqueous solution from the drug supply device 50. is there. More specifically, the measuring device 60 is for collecting a part of the treated water from the water supply path 30 and measuring the hypochlorite ion concentration in the treated water as the chlorine concentration. A color reagent is added and reacted, and the color intensity of the treated water due to this reaction is measured to measure the chlorine concentration of the treated water, that is, the hypochlorite ion concentration. Such a measuring apparatus is described in, for example, Japanese Patent Application Laid-Open No. 2007-93398, and is already known.

  The control device 70 is an electronic information processing organization that stores an operation program of the purification device 1 and includes an information input / output unit. The input side of the input / output unit is for inputting information necessary for the operation of the purification device 1, and an input panel for inputting operation commands and the measurement information output unit of the measuring device 50 are in contact with each other. . Further, the output side of the input / output unit gives necessary operation commands to the pump 11, the first switching valve 23, the second switching valve 32a, the third switching valve 33a, the regenerating device 40, the medicine supply device 50, the measuring device 60, and the like. It is for output.

Next, operation | movement of the purification apparatus 1 is demonstrated based on the operation | movement flowchart of FIG.
When the operator turns on the power switch of the purification device 1, the operation program executes an initial operation in step S1. In this initial operation, the first switching valve 23 is set to the first configuration, the second switching valve 32a is set to communicate with the first water supply path 32 and the main path 31, and the third switching valve 33a is set to the second mode. It sets so that the 2 water supply path 33 and the 2nd drain path 35 may contact.

  After completion of step S1, the operation program proceeds to step S2, and determines whether or not the operator has turned on the operation switch from the input panel. When the operator turns on the operation switch, the operation program moves to step S3 and starts the purification operation of the groundwater. Here, the pump 11 is operated and the pumping of groundwater is started by the water intake path 10. The pumped-up groundwater is supplied to the first unit 21 through the first path 10a and processed by the cation exchanger. Here, since the water intake path 10 is directly connected to the first unit 21 through the first path 10a, the pumped-up groundwater is supplied to the first unit 21 while maintaining a reducing atmosphere. In addition, ammonia nitrogen (ammonium ions) and divalent iron ions and divalent manganese ions contained therein are removed by ion exchange with the cation exchanger. When a strongly acidic cation exchanger is used as the cation exchanger, the hardness component contained in the groundwater is removed together by ion exchange with the cation exchanger.

  The ground water from which each ion has been removed in the first unit 21, that is, the treated water flows from the first water supply path 32 to the main path 31, and a chemical aqueous solution is continuously supplied from the chemical supply device 50. Thereby, the treated water is sterilized by increasing the concentration of hypochlorite ions and oxidizing the remaining organic matter. At this time, since the treatment water has ammonia nitrogen and iron ions and magnesium ions removed in the cation exchange device 20, it is sufficient to add a chemical aqueous solution in an amount necessary for the oxidation or sterilization of organic matter. It is difficult to produce harmful substances such as trihalomethane. Therefore, the treated water sterilized by supplying the aqueous chemical solution is sent through the main path 31 as safe purified water.

  Here, the supply amount of the chemical aqueous solution is constant within a range where the hypochlorite ion concentration in the treated water is sufficiently higher than the concentration necessary for the sterilization treatment of the treated water and less than the regulation value in the drinking water. Is set to a constant flow rate with respect to the unit flow rate of the treated water so as to have a concentration of 1 (hereinafter sometimes referred to as “target concentration”). This concentration is measured by the measuring device 60.

  During such a purifying operation, the operation program determines whether or not the operator has turned the operation switch OFF in step S4. When the operator turns off the operation switch, the operation program proceeds to step S5, and ends after performing a stop operation such as stopping the pump 11, the medicine supply device 50, and the measurement device 60.

  On the other hand, unless the operator operates the operation switch to OFF, the operation program continues the purification operation, and in step S6, the hypochlorite ion concentration of the treated water measured by the measuring device 60 decreases below the reference value. Determine whether or not. Here, the reference value is a concentration arbitrarily set in a concentration range lower than the target concentration. Usually, the hypochlorite ion concentration in the treated water is around the minimum concentration required for the sterilization treatment of the treated water. It is preferable to arbitrarily set a narrow concentration range.

In the first unit 21, the ion exchange ability of the cation exchanger is decreased by continuously treating the groundwater, and breakthrough occurs in which ions to be removed pass without being captured by the first unit 21. Here, the ionic species that breaks through first due to a decrease in the ion exchange capacity of the cation exchanger is ammoniacal nitrogen, and this ammoniacal nitrogen is caused by the chemical aqueous solution supplied from the chemical supply device 50 when it leaks into the treated water. It is converted to nitrogen by reacting with hypochlorite ions. At this time, ammonia nitrogen consumes a large amount of hypochlorite ion (usually, 7 mg Cl ₂ / L equivalent hypochlorite ion is consumed for 1 mg NH ₄ -N / L ammonia nitrogen). Therefore, when breakthrough of ammonia nitrogen occurs, the hypochlorite ion concentration in the treated water starts to decrease rapidly from the target concentration.

  Therefore, when the operation program determines in step S6 that the hypochlorite ion concentration has decreased below the reference value, the operation program proceeds to step S7 and executes the regeneration operation of the cation exchanger of the first unit 21. Here, first, the first switching valve 23 is switched to the second configuration, the third switching valve 33a is switched so that the second water supply path 33 and the main path 31 communicate with each other, and the second switching valve 32a is switched to the first mode. It switches so that the water supply path 32 and the 1st drain path 34 may communicate. Thereby, the groundwater from the water intake path 10 is supplied to the 2nd unit 22 through the 2nd path | route 10b, the ion contained by the ion exchange by the cation exchanger is removed, and flows into the main path 31. For this reason, in the purification device 1, the purification of the groundwater can be continued even during the regeneration operation of the cation exchanger of the first unit 21.

  In the regeneration operation, the regeneration device 40 is operated to supply the regenerant solution from the supply unit 41 to the first unit 21 through the supply path 42. The supplied regenerant solution removes the ions captured by the cation exchanger of the first unit 21 to regenerate the cation exchanger, and the waste liquid containing the removed ions is discharged from the first drain path 34 as a waste path. It flows to 36 and is discarded. The regenerator 40 is preferably set to automatically stop after supplying a specified amount of the regenerant solution by timer control or flow rate control and then rinsing the cation exchanger.

  The operation program returns to step S4 after executing the reproduction operation in step S7, and determines whether or not the operator has turned off the operation switch. As long as the operator does not operate the operation switch to OFF, the operation program continues the purification operation using the second unit 22, and repeats step S6 and subsequent steps. In this case, in the regeneration operation of step S7, the first switching valve 23, the second switching valve 32a, and the third switching valve 33a are switched to the required forms, and the purification of the groundwater is continued by the regenerated first unit 21. The cation exchanger of the second unit 22 is regenerated.

  As described above, since the purification device 1 removes ions such as ammoniacal nitrogen contained in the groundwater by ion exchange in the cation exchanger, the amount of hypochlorite ions supplied to the groundwater for sterilization That is, the amount of the aqueous drug solution can be suppressed, and the operation can be performed economically. Further, the breakthrough of the cation exchanger in the first unit 21 or the second unit used for the treatment of groundwater can be quickly detected based on the concentration of hypochlorite ions supplied for sterilization, In addition, when breakthrough is detected, the unit used is changed to another unit and the cation exchanger of the unit used is regenerated, so that the groundwater can be purified continuously and stably. .

  In addition, the pH of the treated water (purified water) obtained by the purification apparatus 1 can be adjusted as necessary. For example, when an H-type cation exchanger is used, the treated water (purified water) to be obtained becomes weakly acidic. Therefore, it is preferable to adjust the pH if necessary depending on the use of the treated water (purified water).

  In this embodiment, the cation exchange apparatus 20 is provided with two units of the first unit 21 and the second unit 22 and continuously purifies the groundwater while regenerating these units alternately. It is also possible to provide a single unit in the exchange device 20 and change the groundwater purification to be temporarily interrupted during the regeneration of the unit.

  Further, in this embodiment, the treated water supplied with hypochlorite ions is further treated with a membrane separation device, a sedimentation device, or the like before being supplied to a water storage tank or a water channel. It can also be removed.

  Furthermore, the step of detecting breakthrough of the cation exchanger in this embodiment is the treatment of water in a reducing atmosphere containing ammoniacal nitrogen, iron ions and manganese ions other than groundwater by the cation exchanger. The same applies to the case where purified water is prepared by supplying hypochlorite ions to the treated water.

DESCRIPTION OF SYMBOLS 1 Purification apparatus 10 Water intake path 20 Cation exchange apparatus 30 Water supply path 40 Regenerating apparatus 50 Drug supply apparatus 60 Measuring apparatus 70 Control apparatus

Claims (3)

A water intake route for pumping groundwater in a reducing atmosphere containing ammonia nitrogen, iron ions and manganese ions from the ground;
A cation exchange apparatus for obtaining treated water by treating the groundwater from the water intake path directly connected to the water intake path with a cation exchanger;
A water supply path for supplying the treated water from the cation exchange device;
A supply device for supplying hypochlorite ions to the treated water provided in the water supply path;
A measuring device for measuring a hypochlorite ion concentration of the treated water provided on the downstream side of the supply device in the water supply path;
A regenerator for regenerating the cation exchanger;
A control device for operating the reproducing device when a measurement result of the measuring device falls below a preset reference value;
Groundwater purification device equipped with. A step of obtaining treated water by treating ground water in a reducing atmosphere containing ammoniacal nitrogen, iron ions and manganese ions pumped from the ground with a cation exchanger;
Supplying hypochlorite ions to the treated water;
Measuring the hypochlorite ion concentration of the treated water supplied with hypochlorite ions;
Regenerating the cation exchanger when the hypochlorite ion concentration falls below a preset reference value;
Including groundwater purification methods. Treated water with a reducing atmosphere containing ammonia nitrogen, iron ions and manganese ions is treated with a cation exchanger to obtain treated water, and purified water is supplied by supplying hypochlorite ions to the treated water. A method for detecting breakthrough of a cation exchanger in the preparation,
Measuring the hypochlorite ion concentration of the treated water supplied with hypochlorite ions;
Determining whether the hypochlorite ion concentration has dropped below a preset reference value;
Method for detecting breakthrough of cation exchanger including

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