JP2014034010A - Cleaning apparatus and cleaning method of subterranean water - Google Patents

Abstract

A residual chlorine concentration of water to be treated after purification treatment is easily maintained at a predetermined concentration.
In a purification apparatus for groundwater, a first sodium hypochlorite adding means adds sodium hypochlorite to remove impurities contained in water to be treated. The activated carbon tower 40 is used for the purpose of removing residual chlorine contained in the water to be treated 18 when the water to be treated 18 is passed through. Further, the second sodium hypochlorite adding means 42 adds sodium hypochlorite to make the residual chlorine concentration of the water to be treated 18 a predetermined concentration. Accordingly, while the first sodium hypochlorite adding means 22 removes impurities contained in the water to be treated 18, the activated carbon tower 40 and the second sodium hypochlorite adding means 42 are used for the treatment. Since the residual chlorine concentration of the water 18 can be controlled, the residual chlorine concentration of the water to be treated 18 after the purification treatment can be easily maintained at a predetermined concentration.
[Selection] Figure 1

Description

  The present invention relates to a groundwater purification treatment apparatus and a purification treatment method.

  In recent years, the demand for groundwater has increased as a source of water that is not affected by disasters and weather. In general, groundwater pumped from the ground contains impurities such as iron, manganese, and ammonia. When using the groundwater, the groundwater is subjected to purification treatment to remove or remove these impurities. There is a need to reduce. For this reason, various methods and devices for purifying groundwater have been proposed (for example, see Patent Document 1). As an example, when the concentration of iron contained in groundwater is about 1 mg / L, the concentration of manganese is about 0.1 mg / L, and the concentration of ammoniacal nitrogen is about 0.5 mg / L, generally, FIG. The purification treatment is performed using a device such as the groundwater purification treatment device 100 shown in FIG.

  In the groundwater purification treatment apparatus 100 of FIG. 3, groundwater pumped by a well pump 14 installed in the well 12 (hereinafter referred to as “treated water”) is temporarily stored in the raw water tank 16. Sodium hypochlorite is added to the treated water 18 in the raw water tank 16 from the sodium hypochlorite storage tank 20 through the sodium hypochlorite supply pump 22a and the pipe 22b. And the to-be-treated water 18 in the raw water tank 16 is aerated by the blower 24, and iron and manganese contained in the to-be-treated water 18 are insoluble due to the aeration effect and the oxidation effect of sodium hypochlorite. It becomes a solid compound and ammonia nitrogen is removed after generating nitrogen gas by discontinuous point chlorination. Under the present circumstances, in order to advance these series of reactions reliably, the raw | natural water tank 16 is provided with the residence time of about 0.5 to 1 hour. In addition, considering that the residual chlorine consumed in the treated water 18 is about 0.1 to 0.2 mg / L before the treated water 18 reaches the treated water tank 32 described later from the raw water tank 16, The residual chlorine concentration of the water to be treated 18 in the raw water tank 16 needs to be maintained at about 0.4 to 0.6 mg / L. Subsequently, the water to be treated 18 in the raw water tank 16 is pumped by the raw water pump 26, filtered through the sand filtration tower 28 and the filtration membrane 30 such as MF membrane or UF membrane, and then stored in the treated water bath 32. Is done. And the to-be-treated water 18 stored in the treated water tank 32 is confirmed by manual analysis or the like that the residual chlorine concentration is a set allowable value, for example, 0.3 to 0.4 mg / L. 34 is transferred through a pipe 36 to a water receiving tank (not shown).

JP 2005-118664 A

By the way, in the groundwater purification apparatus 100 of FIG. 3, the iron contained in the to-be-processed water 18 by aeration in the raw | natural water tank 16 and addition of sodium hypochlorite is bivalent iron Fe ^<+2>. Is oxidized to trivalent iron Fe ⁺³ , and manganese is oxidized from divalent manganese Mn ⁺² to tetravalent manganese Mn ⁺⁴ . Ammonia nitrogen NH ₄ —N generates nitrogen gas by discontinuous point chlorination, and the generated nitrogen gas is diffused into the atmosphere. In the treatment of these iron, manganese and ammoniacal nitrogen, if the amount of sodium hypochlorite added is small, the removal rate of iron and manganese will be reduced and the production of chloramine (bound chlorine) will be caused. Further, in order to sufficiently remove iron, manganese and ammonia nitrogen, if the amount of sodium hypochlorite added is increased, residual chlorine for lowering the residual chlorine concentration of the water to be treated 18 in the treated water tank 32. It is necessary to add sodium thiosulfate or sodium sulfite as a neutralizing agent (reducing agent). Further, since a control device, a reaction vessel, a stirring device and the like for performing the neutralization work are necessary, the initial cost and the running cost are increased, and further labor for chemical management is generated.

Furthermore, as described above, considering that the residual chlorine consumed in the treated water 18 between the raw water tank 16 and the treated water tank 32 is usually about 0.1 to 0.2 mg / L, In order to set the residual chlorine concentration of the treated water 18 in the treated water tank 32 to a set allowable value, the residual chlorine concentration of the treated water 18 in the raw water tank 16 is about 0.4 to 0.6 mg / L. It needs to be kept high. However, the concentrations of iron, manganese, and ammonia contained in groundwater are not always constant, and there are daily fluctuations and seasonal fluctuations, and each component fluctuates in a non-trend. It is difficult to maintain the residual chlorine concentration of 18 at the set allowable value of 0.3 to 0.4 mg / L at all times.
This invention is made | formed in view of the said subject, The place made into the objective is to maintain easily the residual chlorine density | concentration of the to-be-processed water after a purification process to a predetermined density | concentration.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

  (1) A groundwater purification treatment apparatus, comprising: first sodium hypochlorite addition means for adding sodium hypochlorite to treated water to remove impurities; and residual chlorine in the treated water. An apparatus for purifying groundwater comprising an activated carbon tower for removal and a second sodium hypochlorite addition means for adding sodium hypochlorite to make the residual chlorine concentration of the treated water a predetermined concentration (Claim 1).

The groundwater purification treatment apparatus described in this section includes a first sodium hypochlorite addition means, an activated carbon tower, and a second sodium hypochlorite addition means. The sodium chlorate adding means adds sodium hypochlorite to the water to be treated in order to remove impurities such as iron, manganese and ammonia contained in the water to be treated. Thereby, iron and manganese become insoluble solid compounds and are removed from the water to be treated. At this time, the reaction to the solid compounds may be promoted by aeration of the water to be treated. Ammonia is also removed after generating nitrogen by discontinuous chlorination.
In addition, the activated carbon tower is not used for the purpose of adsorbing and removing organic matter or chromaticity in the water to be treated, but for the purpose of removing residual chlorine contained in the water to be treated. Is passed through the activated carbon tower to remove residual chlorine in the water to be treated.

Furthermore, the second sodium hypochlorite adding means is not intended to remove impurities contained in the water to be treated, but in order to make the residual chlorine concentration of the water to be treated a predetermined concentration, Sodium chlorate is added. For this reason, it is not necessary to consider the content of impurities in the water to be treated, and it is only necessary to add sodium hypochlorite in an amount that takes into consideration only the target residual chlorine concentration of the water to be treated.
Therefore, the groundwater purification treatment apparatus described in this section uses the first sodium hypochlorite addition means to remove impurities contained in the water to be treated, while the activated carbon tower and the second hypochlorous acid. Since the sodium addition means controls the residual chlorine concentration of the water to be treated, the residual chlorine concentration of the water to be treated after the purification treatment can be easily maintained at a predetermined concentration.

(2) In the above item (1), it includes a raw water tank for storing the treated water pumped from the underground, and the first sodium hypochlorite adding means is the treated object in the raw water tank. Sodium hypochlorite is added to water, and the second sodium hypochlorite adding means is for adding sodium hypochlorite to the treated water after passing through the activated carbon tower. An apparatus for purifying groundwater (claim 2).
The groundwater purification treatment apparatus described in this section includes a raw water tank for storing groundwater pumped from a well or the like as treated water, and with respect to the treated water stored in the raw water tank. The first sodium hypochlorite adding means adds sodium hypochlorite. That is, impurities to be treated are first removed by adding sodium hypochlorite to the water to be treated pumped from underground.

The second sodium hypochlorite addition means is for adding sodium hypochlorite to the water to be treated from which residual chlorine has been removed by passing water through the activated carbon tower. That is, by adding sodium hypochlorite to the water to be treated whose residual chlorine concentration has become substantially zero, the residual chlorine concentration of the water to be treated is easily adjusted to the target concentration. .
Therefore, the groundwater purification treatment apparatus described in this section removes impurities contained in the treated water pumped from the underground by the first sodium hypochlorite addition means, and hypochlorous acid at this time Residual chlorine contained in the water to be treated due to the addition of sodium is once removed by passing the water to be treated through an activated carbon tower, and again treated by the second sodium hypochlorite addition means. Sodium hypochlorite is added so that the residual chlorine concentration of water becomes the target concentration. Thereby, the residual chlorine concentration of the water to be treated after the purification treatment is easily maintained at a predetermined concentration.

(3) In the above (1) (2) of the activated carbon column, the purification treatment of ground water which treated water is activated carbon is filled to passing water was at a space velocity of 20 to 25 m 3 / ^m 3 ^· Device (claim 3).
Purifying apparatus of groundwater according to the above, activated carbon is filled in the activated carbon tower is one that is filled to the water to be treated passing water at a space velocity 20~25m 3 / ^m 3 ^· . The value of this space velocity is the residual that is contained in the water to be treated as a result of adding sodium hypochlorite to the water to be treated for removing impurities by the first sodium hypochlorite adding means. It is a value sufficient to remove chlorine from the water to be treated, and is a value found by the inventors' verification. The value of the space velocity is clearly a large value compared with the space velocity of the activated carbon tower used for the purpose of adsorbing and removing organic matter and chromaticity in the water to be treated. That is, in the groundwater purification treatment apparatus described in this section, the activated carbon tower is not used for adsorbing and removing organic matter, chromaticity, etc. in the treated water, but for removing residual chlorine in the treated water. The activated carbon used for adsorbing and removing organic matter, chromaticity, etc. is less charged than the activated carbon tower, and the replacement period of the activated carbon is longer. It is.

(4) In the above item (3), as the amount of sodium hypochlorite added by the first sodium hypochlorite adding means, the residual chlorine concentration of the treated water after addition is 0.4 to 1 An apparatus for purifying groundwater set to be 0.0 mg / L (Claim 4).
In the groundwater purification treatment apparatus described in this section, the amount of sodium hypochlorite added to the water to be treated by the first sodium hypochlorite addition means includes iron, manganese, In consideration of sufficiently removing impurities such as ammonia, the residual chlorine concentration of the water to be treated is set to 0.4 to 1.0 mg / L. The residual chlorine concentration, the water to be treated, (3) by space velocity indicated in the section is passed through the activated carbon column at 20 to 25 m 3 / ^m 3 ^·, the concentration can be sufficiently removed. That is, the addition of sodium hypochlorite from the first sodium hypochlorite addition means sufficiently removes impurities in the water to be treated, while the residual chlorine concentration can be sufficiently removed by the activated carbon tower. is there.

(5) In the above items (1) to (4), a treated water tank for storing the treated water after purification treatment, a circulation pump for circulating the treated water in the treated water tank, A groundwater purification treatment apparatus including a residual chlorine measuring device that constantly measures the residual chlorine concentration of the treated water circulating in the treated water tank (Claim 5).
The groundwater purification treatment apparatus described in this section includes a treated water tank for storing treated water after purification treatment, a circulation pump for circulating the treated water, and a residual chlorine measuring device for measuring residual chlorine concentration in the treated water Is included. The treated water after purification treatment is stored in the treated water tank while being circulated by a circulation pump, and the amount of circulating water at this time is such that the residual chlorine concentration is maintained uniformly in the treated water tank. The amount of water that can be exchanged in about 1 hour is taken as a guide. And the residual chlorine measuring device always measures the residual chlorine concentration of the to-be-treated water circulating in this treated water tank. That is, the treated water in the treated water tank is circulated by a circulation pump so that the residual chlorine concentration becomes uniform as a whole. Therefore, by measuring the treated water in such a state, It will properly measure the chlorine concentration. In addition, since the residual chlorine concentration is continuously measured by the residual chlorine measuring device, even if the residual chlorine concentration is outside the specified range, the abnormality is detected early and the residual chlorine concentration Quick response when the concentration is abnormal.

(6) A method for purifying groundwater, the first sodium hypochlorite addition step of adding sodium hypochlorite to the treated water to remove impurities, and the treated water into the activated carbon tower A purification process of groundwater including an activated carbon flow process for passing water and a second sodium hypochlorite addition process for adding sodium hypochlorite to make the residual chlorine concentration of the treated water a predetermined concentration. A method (claim 6).
(7) In the first sodium hypochlorite addition step in the above (6), sodium hypochlorite is added to the treated water stored in the raw water tank after being pumped from the underground In the second sodium hypochlorite addition step, the groundwater purification treatment method of adding sodium hypochlorite to the treated water after the activated carbon flow step (Claim 7).
(8) (6) (7) in the section in the activated carbon water passage step, the purification treatment process of groundwater passing water treatment water was at a space velocity 20~25m ³ / ^{m 3} · the activated carbon column ( Claim 8).

(9) In said 1st sodium hypochlorite addition process in said (8) term, the residual chlorine concentration of the said to-be-processed water after adding the addition amount of sodium hypochlorite is 0.4- A groundwater purification treatment method set to 1.0 mg / L (claim 9).
(10) In the above items (6) to (9), a circulation step for circulating the treated water after purification treatment in the treated water tank, and a monitoring for constantly monitoring the residual chlorine concentration of the circulating treated water A method for purifying groundwater comprising a step (claim 10).
The groundwater purification methods described in the items (6) to (10) are executed using the groundwater purification devices described in the items (1) to (5), respectively. The equivalent action corresponding to the items 1) to (5) is exhibited.

  Since this invention was comprised in this way, it becomes possible to maintain easily the residual chlorine density | concentration of the to-be-processed water after a purification process to a predetermined density | concentration.

It is a schematic diagram which shows typically the purification treatment apparatus of the groundwater which concerns on embodiment of this invention. It is a flowchart which shows an example of the purification process of the groundwater performed using the purification apparatus for groundwater which concerns on embodiment of this invention. It is a schematic diagram which shows the conventional purification process of groundwater.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 1 is a schematic diagram schematically showing a groundwater purification treatment apparatus 10 according to an embodiment of the present invention. The groundwater purification treatment apparatus 10 according to the embodiment of the present invention is added with the following equipment in comparison with the conventional groundwater purification treatment apparatus 100 shown in FIG. First, the activated carbon tower 40 is installed in the flow path of the treated water 18 between the sand filtration tower 28 and the filtration membrane 30. Furthermore, in the flowing water path between the activated carbon tower 40 and the filtration membrane 30, it comprises a sodium hypochlorite supply pump 42a and a pipe 42b for adding sodium hypochlorite to the treated water 18. Second sodium hypochlorite adding means 42 is installed. In addition, a circulating pump 50 is connected to the treated water tank 32, and the treated water 18 in the treated water tank 32 is circulated. Further, the circulation path by the circulation pump 50 is provided with a branch path to the residual chlorine measuring device 52, and the treated water 18 measured by the residual chlorine measuring device 52 is drained to the sewer via the pipe 54. It has become so.

Next, along the flowchart shown in FIG. 2, a groundwater purification processing method executed using the groundwater purification processing apparatus 10 will be described with reference to FIG. 1.
S10 (groundwater pumping): Groundwater is pumped from the well 12 by the well pump 14 and stored in the raw water tank 16 as treated water 18.
S20 (sodium hypochlorite addition): from the sodium hypochlorite storage tank 20 through the first sodium hypochlorite addition means 22 constituted by the sodium hypochlorite supply pump 22a and the pipe 22b. Sodium hypochlorite is added to the treated water 18 stored in the raw water tank 16. The amount of sodium hypochlorite added at this time is sufficient to remove impurities such as iron, manganese, and ammonia contained in the water to be treated 18 according to the quality of the water to be treated 18 in the raw water tank 16. The residual chlorine concentration (for example, 0.4 to 1.0 mg / L) is set.

S30 (Aeration in the raw water tank): The treated water 18 in the raw water tank 16 is aerated by the blower 24. Thereby, the impurities contained in the water to be treated 18 are removed by the oxidation effect of the sodium hypochlorite added in S20 and the aeration effect of the blower 24. Specifically, the iron to be treated 18 contains iron that is oxidized from divalent iron Fe ⁺² to trivalent iron Fe ⁺³ , and manganese is oxidized from divalent manganese Mn ⁺² to tetravalent manganese Mn ⁺⁴ , Each becomes an insoluble solid compound. Ammonia nitrogen NH ₄ —N generates chloramine by reaction with chlorine, and further decomposes and removes nitrogen gas by discontinuous point chlorination. In order to make a series of reactions related to the removal of these impurities proceed reliably, the residence time of the treated water 18 in the raw water tank 16 is preferably about 0.5 to 1 hour. Thereby, impurities, such as iron, manganese, ammonia, which the to-be-processed water 18 contains are removed.

S50 (pumping from the raw water tank): The treated water 18 from which impurities have been removed in the steps S20 and S30 is pumped from the raw water tank 16 by the raw water pump 26.
S60 (sand filtration tower filtration): In S50, the water to be treated 18 pumped from the raw water tank 16 is filtered by the sand filtration tower 28, and impurities in the water to be treated 18 are further removed.
S70 (activated carbon tower water flow): In S60, the water to be treated 18 filtered by the sand filtration tower 28 is passed through the activated carbon tower 40. The activated carbon column 40 is activated carbon is filled as treated water 18 is passing water at a space velocity 20~25m ³ / ^{m 3} ·. By passing the water through the activated carbon tower 40, residual chlorine that has been contained in the water to be treated 18 by the addition of sodium hypochlorite in S20 is temporarily removed.

S80 (addition of sodium hypochlorite): The sodium hypochlorite supply tank 42a and the pipe 42b from the sodium hypochlorite storage tank 20 to the treated water 18 from which residual chlorine has been removed in S70 above. Sodium hypochlorite is added again through the constituted second sodium hypochlorite adding means 42. The amount of sodium hypochlorite added at this time is set so that the treated water 18 after purification treatment has a target predetermined residual chlorine concentration (for example, 0.3 to 0.4 mg / L). .
S90 (filtration membrane filtration): The filtration membrane 30 composed of MF membrane (microfiltration membrane), UF membrane (ultrafiltration membrane), etc., from the treated water 18 to which sodium hypochlorite is added in S80 above. To remove microorganisms and bacteria contained in the water to be treated 18. As the MF film or UF film, a PVDF film, PVC film, PE film, or the like that is durable against residual chlorine is used.
S100 (transfer to treated water tank): In S90, the water to be treated 18 filtered by the filtration membrane 30 is transferred to the treated water tank 32 and stored in the treated water tank 32.

S110 (circulation in the treated water tank): The circulation pump 50 connected to the treated water tank 32 is used to form a circulation path through the circulation pump 50, and the treated water 18 in the treated water tank 32 is circulated.
S120 (residual chlorine concentration measurement / monitoring): A part of the circulated water 18 to be circulated from the circulation path formed by the circulation pump 50 through the branch path, and collected by the residual chlorine measuring device 52. The residual chlorine concentration of the water 18 to be treated is measured. This measurement is continuously performed while the treated water 18 is stored in the treated water tank 32. And the residual chlorine concentration of the to-be-processed water 18 is always monitored, and when the measured residual chlorine concentration of the to-be-processed water 18 is always in the predetermined range of the target residual chlorine concentration (OK), it progresses to S130. If it is determined that the target residual chlorine concentration is outside the predetermined range (NG), the process proceeds to S140. In addition, the to-be-processed water 18 measured by the residual chlorine measuring apparatus 52 is drained to the sewer through the pipe 54.
S130 (transfer to water receiving tank): When the residual chlorine concentration of the water to be treated 18 is always within the predetermined range of the target residual chlorine concentration in S120 (OK), the water is stored in the treated water tank 32. The treated water 18 is transferred to the water receiving tank (not shown) through the pipe 36 by the treated water pump 34.

S140 (Abnormality alarm notification): When the residual chlorine concentration of the water to be treated 18 is outside the predetermined range of the target residual chlorine concentration (NG) in S120, an abnormal alarm is issued from the residual chlorine measuring device 52. Is issued. By issuing this abnormality alarm, the administrator of the groundwater purification treatment apparatus 10 knows that the residual chlorine concentration of the treated water 18 in the treated water tank 32 is abnormal.
S150 (Purification treatment device stop): Upon receiving an abnormality alarm from the residual chlorine measuring device 52, the treatment water pump 34 for transferring the treated water 18 in the treatment water tank 32 is automatically stopped and simultaneously purified. The processing apparatus 10 automatically stops. After that, the work to cope with when the residual chlorine concentration is abnormal is performed, and the return procedure to the normal operation such as the release of the abnormality alarm from the residual chlorine measuring device 52 and the restart of the groundwater purification treatment device 10 is executed. To do. Details of this procedure are omitted.

Here, the activated carbon tower 40 used in the groundwater purification treatment apparatus 10 according to the embodiment of the present invention for removing residual chlorine from the water to be treated 18 will be described in detail. The activated carbon tower 40 is not intended to adsorb and remove organic matter and chromaticity in the water to be treated 18 but is used for the purpose of removing residual chlorine as described above. The normal activated carbon tower used for the purpose of adsorbing and removing organic matter and chromaticity has a space velocity (hereinafter referred to as “SV”) of about 10 m ³ / m ³ · hour, whereas the activated carbon tower 40 It has been proved by the present inventors that a sufficient activated carbon removal effect can be obtained with a small activated carbon tower having an SV of about 20 to 25 m ³ / m ³ · hr.
Moreover, the replacement cycle of the activated carbon in the activated carbon tower, which is used for removing organic substances and chromaticity, is usually 1 to 3 months, at most about 6 months to 1 year, but it is used for removing residual chlorine. In the simulation conducted by the present inventors, the activated carbon in the activated carbon tower 40 has been shown to require no supplementation or replacement for 3 years or more.

Further, specific numerical values will be given for explanation. When the operation time of the groundwater purification treatment apparatus 10 is 15 hours / day, the purification treatment amount is 10 m ³ / hour, and the SV of the activated carbon tower 40 is 20 m ³ / m ³ · hour, the activated carbon packed volume of the activated carbon tower 40 is ,
10 m ³ / hour / 20 m ³ / m ³ · hour = 0.50 m ³
It becomes. Here, the effective chlorine concentration of general commercially available sodium hypochlorite is about 12%, and the hypochlorous acid generation formula is
2NaOH + Cl2 → NaCl + NaClO + H2O
In view of the chemical equilibrium of 1 mole of NaClO (74.5 g molecule) per mole of available chlorine (residual chlorine) Cl2 (70.9 g molecule) Assuming that the residual chlorine concentration of 18 is a maximum of 1.0 mg / L (= 1.0 g / m ³ ), the amount of sodium hypochlorite for 3 years flowing into the activated carbon tower 40 is
10m ³ / hour × 15 hours / day × 365 days / year × 3 years
^{× 1.0g / m 3 × 74.5 /} 70.9 = 173,000g
It becomes.

Further, activated carbon C (12 g molecule) packed in the activated carbon tower 40 and sodium hypochlorite NaClO (74.5 g molecule) react at a molar ratio of 1: 2 to generate carbon dioxide CO2. Calculating the mass of activated carbon that disappears in 3 years under the above conditions,
173,000 g (NaClO) × 12 g (C) /74.5 g (NaClO)
= 27,900 g (C) = 27.9 kg (C)
It becomes. That is, when the bulk density of the activated carbon is 0.5 L / kg (C), among the 0.50 m ³ activated carbon initially charged in the activated carbon tower 40, the activated carbon filling volume that disappears in 3 years is calculated.
27.9 kg (C) /0.5 L / kg (C) = 55.8 L
It becomes. Therefore, the SV of the activated carbon tower 40 after 3 years is assumed that the activated carbon filling volume disappearing in 3 years is 55.8 L (= 0.0558 m ³ ), and the activated carbon is not replenished.
10m ³ / hr / (0.50m ³ - 0.0558m ³⁾
= 22.5 m ³ / m ³ · hour. This value is a value that can remove residual chlorine from the water to be treated 18.

  The above calculation was performed on the assumption that the residual chlorine concentration of the treated water 18 passed through the activated carbon tower 40 was 1.0 mg / L at the maximum, and the treated water passed through the activated carbon tower 40. An average value of 18 actual residual chlorine concentrations is expected to be significantly lower than 1.0 mg / L. For this reason, it is estimated that the activated carbon tower 40 used in the groundwater purification apparatus 10 according to the embodiment of the present invention can maintain the effect of removing residual chlorine without supplementing or replacing the activated carbon for 3 years or more.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained. That is, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention, as shown in FIG. 1, is a first sodium hypochlorite addition means composed of a sodium hypochlorite supply pump 22a and a pipe 22b. 22, an activated carbon tower 40, and a second sodium hypochlorite adding means 42 including a sodium hypochlorite supply pump 42 a and a pipe 42 b. The first sodium hypochlorite adding means 22 adds sodium hypochlorite to the water to be treated 18 in order to remove impurities such as iron, manganese and ammonia contained in the water to be treated 18 (FIG. 2 S20). Thereby, iron and manganese become insoluble solid compounds and are removed from the water to be treated 18. At this time, the water to be treated 18 is aerated by the blower 24 (see S30 in FIG. 2), thereby solidifying the solid. The reaction to the compound should be promoted. Ammonia is also removed after generating nitrogen by discontinuous chlorination.
The activated carbon tower 40 is not used for the purpose of adsorbing and removing organic matter and chromaticity in the water to be treated 18, but for the purpose of removing residual chlorine contained in the water to be treated 18. The treated water 18 is passed through the activated carbon tower 40 (see S70 in FIG. 2), whereby residual chlorine in the treated water 18 is removed.

Further, the second sodium hypochlorite adding means 42 is not intended to remove impurities contained in the water to be treated 18, but in order to make the residual chlorine concentration of the water to be treated 18 a predetermined concentration, 18, sodium hypochlorite is added (see S80 in FIG. 2). For this reason, it is not necessary to consider the content of impurities in the water to be treated 18, and it is only necessary to add sodium hypochlorite in an addition amount considering only the target residual chlorine concentration of the water to be treated 18. is there.
Therefore, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention uses the first sodium hypochlorite addition means 22 to remove the impurities contained in the treated water 18 while Since the residual chlorine concentration of the water to be treated 18 can be controlled by the second sodium hypochlorite adding means 42, the residual chlorine concentration of the water to be treated 18 after the purification treatment can be easily set to a predetermined concentration. Can be maintained.

Moreover, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention includes a raw water tank 16 for storing the groundwater pumped from the well 12 as the water to be treated 18, and is stored in the raw water tank 16. The first sodium hypochlorite adding means 22 adds sodium hypochlorite to the water to be treated 18. That is, impurities to be treated are first removed from the treated water 18 pumped from the base by adding sodium hypochlorite.
The second sodium hypochlorite adding means 42 is for adding sodium hypochlorite to the treated water 18 from which residual chlorine has been removed by passing water through the activated carbon tower 40. . That is, by adding sodium hypochlorite to the water to be treated 18 whose residual chlorine concentration has become substantially zero, the residual chlorine concentration of the water to be treated 18 can be easily adjusted to the target concentration. Can do.

  Therefore, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention removes impurities contained in the water to be treated 18 pumped from the underground by the first sodium hypochlorite adding means 22. Residual chlorine contained in the water to be treated 18 due to the addition of sodium hypochlorite at that time is once removed by passing the water to be treated 18 through the activated carbon tower 40, and again the second hypochlorous acid. Sodium hypochlorite is added by the sodium chlorate adding means 42 so that the residual chlorine concentration of the treated water 18 becomes a target concentration. Thereby, the residual chlorine density | concentration of the to-be-processed water 18 after a purification process can be easily maintained at a predetermined density | concentration.

Furthermore, purification treatment apparatus 10 of the ground water according to the embodiment of the present invention, activated carbon is filled in the activated carbon column 40 is such that the treated water 18 is passing water at a space velocity 20~25m 3 / ^m 3 ^· Is filled. This space velocity value is included in the water to be treated 18 as a result of adding sodium hypochlorite to the water to be treated 18 for removing impurities by the first sodium hypochlorite adding means 22. This value is sufficient to remove the residual chlorine from the water to be treated 18, and is a value found by the verification by the present inventors. The value of the space velocity is clearly a large value as compared with the space velocity of the activated carbon tower used for the purpose of adsorbing and removing organic matter and chromaticity in the water to be treated 18. That is, in the groundwater purification treatment apparatus 10 according to the embodiment of the present invention, the activated carbon tower 40 is not used for adsorbing and removing organic matter, chromaticity, and the like in the treated water 18. Since it is used to remove residual chlorine in 18, it is possible to make the charged amount of activated carbon smaller than that of the activated carbon tower used to adsorb and remove organic matter and chromaticity. Furthermore, it is possible to lengthen the replacement period of the activated carbon.

Further, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention is such that the amount of sodium hypochlorite added to the treated water 18 by the first sodium hypochlorite adding means 22 is equal to the treated water. In consideration of sufficiently removing impurities such as iron, manganese, ammonia, etc. contained in 18, the residual chlorine concentration of the water to be treated 18 is set to 0.4 to 1.0 mg / L. Is. The residual chlorine concentration, the water to be treated 18, a space velocity described above is by passed through an activated carbon column 40 at 20~25m 3 / ^m 3 ^·, the concentration can be sufficiently removed. That is, the addition of sodium hypochlorite from the first sodium hypochlorite adding means 22 can sufficiently remove impurities in the water to be treated 18 while the residual chlorine concentration can be sufficiently removed by the activated carbon tower 40. Can be removed.

  Furthermore, the groundwater purification treatment apparatus 10 according to the embodiment of the present invention includes a treated water tank 32 that stores the treated water 18 after the purification treatment, a circulation pump 50 that circulates the treated water 18, and the treated water 18. And a residual chlorine measuring device 52 for measuring the residual chlorine concentration. The treated water 18 after the purification treatment is stored in the treated water tank 32 while being circulated by the circulation pump 50 (see S110 in FIG. 2), and the amount of circulating water at this time has a residual chlorine concentration in the treated water tank 32. As a guide, the amount of water that can be exchanged in the treated water tank 32 in about 1 hour is used as a guide. The residual chlorine measuring device 52 always measures the residual chlorine concentration of the water to be treated 18 circulating in the treated water tank 32 (see S120 in FIG. 2). That is, since the treated water 18 in the treated water tank 32 is circulated by the circulation pump 50, the residual chlorine concentration becomes uniform as a whole, and thus the treated water 18 in such a state is measured. Thus, the residual chlorine concentration can be properly measured. In addition, since the measurement of the residual chlorine concentration by the residual chlorine measuring device 52 is continuously performed, even when the residual chlorine concentration is outside the predetermined range, the abnormality is detected early and the residual chlorine concentration It becomes possible to quickly deal with an abnormal chlorine concentration.

  10: Groundwater purification apparatus, 16: Raw water tank, 18: Water to be treated, 22: First sodium hypochlorite addition means, 32: Treated water tank, 40: Activated carbon tower, 42: Second hypochlorous acid Sodium acid addition means, 50: circulation pump, 52: residual chlorine measuring device

Claims (10)

A groundwater purification device,
First sodium hypochlorite addition means for adding sodium hypochlorite to the water to be treated to remove impurities;
An activated carbon tower for removing residual chlorine in the treated water;
And a second sodium hypochlorite adding means for adding sodium hypochlorite to make the residual chlorine concentration of the water to be treated a predetermined concentration. Including a raw water tank for storing the treated water pumped from underground,
The first sodium hypochlorite adding means is for adding sodium hypochlorite to the treated water in the raw water tank,
The said 2nd sodium hypochlorite addition means adds sodium hypochlorite to the said to-be-processed water after passing through the said activated carbon tower, Purification of groundwater of Claim 1 characterized by the above-mentioned. Processing equipment. The groundwater purification apparatus according to claim 1 or 2, wherein the activated carbon tower is filled with activated carbon so that the water to be treated passes through at a space velocity of 20 to 25 m ³ / m ³ · h. .   The amount of sodium hypochlorite added by the first sodium hypochlorite addition means is set so that the residual chlorine concentration of the treated water after addition is 0.4 to 1.0 mg / L. The apparatus for purifying groundwater according to claim 3.   A treated water tank for storing the treated water after purification treatment, a circulation pump for circulating the treated water in the treated water tank, and a residual of the treated water circulating in the treated water tank The groundwater purification apparatus according to any one of claims 1 to 4, further comprising a residual chlorine measuring apparatus that constantly measures a chlorine concentration. A method for purifying groundwater,
A first sodium hypochlorite addition step of adding sodium hypochlorite to the water to be treated to remove impurities;
An activated carbon water passing step for passing the treated water through an activated carbon tower;
And a second sodium hypochlorite addition step of adding sodium hypochlorite to make the residual chlorine concentration of the treated water a predetermined concentration. In the first sodium hypochlorite addition step, after being pumped from underground, sodium hypochlorite is added to the treated water stored in the raw water tank,
The method for purifying groundwater according to claim 6, wherein, in the second sodium hypochlorite addition step, sodium hypochlorite is added to the treated water after the activated carbon water passing step. In the activated carbon water flow process, purification treatment method according to claim 6 or 7 groundwater wherein the water to pass through at a time space velocity 20~25m 3 / ^m 3 ^· the treated water to the activated carbon column.   In the first sodium hypochlorite addition step, the amount of sodium hypochlorite added is set so that the residual chlorine concentration of the treated water after addition is 0.4 to 1.0 mg / L The method for purifying groundwater according to claim 8.   10. A circulation step of circulating the treated water after purification treatment in a treated water tank, and a monitoring step of constantly monitoring a residual chlorine concentration of the circulating treated water. The method for purifying groundwater according to any one of the above.

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