JP2020131189A - Disinfection apparatus and disinfection method for reducing colon bacilli or colon bacilli group in waste water containing ammonia nitrogen - Google Patents

Abstract

To provide a method and an apparatus for disinfecting waste water containing ammonia nitrogen by adding a disinfectant excellent in handleability.SOLUTION: In a disinfection method, a disinfectant containing hypochlorous acid is added to waste water containing ammonia nitrogen immediately after the disinfectant is prepared by dissolving a specific amount of a solid source (B) of hypochlorous acid in an agent (A) containing a bromine ion. A disinfection apparatus includes a mixing unit 1 for adding the solid source (B) of hypochlorous acid to the agent (A) for mixing, a disinfectant preparation unit 2 for receiving the mixture from the mixing unit 1 and preparing the disinfectant by dissolving the solid source (B) of hypochlorous acid in the agent (A), a first line 3 for supplying the agent (A) to the disinfectant preparation unit 2, and a disinfectant supply line 4 for supplying the disinfectant to the waste water containing ammonia nitrogen from the disinfectant preparation unit 2 immediately after the disinfectant is prepared.SELECTED DRAWING: Figure 1

Description

The present invention relates to a disinfection device and a disinfection method for ammonia nitrogen-containing wastewater, and particularly disinfects Escherichia coli or coliform bacteria from ammonia nitrogen-containing wastewater discharged from a sewage treatment plant, a pumping station, or a rainwater spout to a public water area. Regarding equipment and disinfection methods.

A sewage treatment plant is a facility for detoxifying sewage discharged from homes and factories and discharging it into public water bodies. If the inflow sewage significantly exceeds the treatment capacity, such as when there is rainfall exceeding the design value, some of the sewage in rainy weather is simply treated and then discharged, so it is discharged from the pumping station or rainwater outlet, which is a relay station. , Sewage mixed with rainwater (hereinafter referred to as "sewage in rainy weather") is discharged into public water areas without being sufficiently treated. In this case, coarse suspended solids and SS (suspended substance) are discharged into public water areas, which may be aesthetically unpleasant, and the discharge standard value (3000 CFU / mL) stipulated in the Water Pollution Control Law. Coliform bacteria and coliforms that greatly exceed the following) may be detected. These are phenomena that are particularly seen in confluence sewers, but even in confluence sewers, soil coliforms and coarse suspended matter flow in, so if they overflow and are discharged into public water areas, they will merge. There was a problem similar to that of the type sewerage system. In addition, Escherichia coli refers only to Esherichia coli, whereas coliforms include Citrobacter, Enterobacter, Klebsiella, etc. in addition to Esherichia coli. Coliform bacteria are an index of fecal contamination and are inspection items for confirming the safety against intestinal pathogens (typhus, Shigella, etc.).

For disinfection at sewage treatment plants, "Sewerage Facility Planning / Design Guidelines and Explanations" (published by the Japan Sewerage Association, 2009 edition) includes sodium hypochlorite, liquefied chlorine, chlorinated isocyanuric acid, calcium hypochlorite, etc. A method of disinfecting a group of Escherichia coli by contacting them with sewage in a mixing pond for 15 minutes or more using the chlorine agents of the above is shown. Chlorine-based disinfectants generate hypochlorous acid, which is a free base, in sewage, destroy cell membranes and cell walls of pathogenic substances such as microorganisms and viruses with strong oxidizing power, and denature proteins and nucleic acids in cells. In addition, "Sewerage facility planning / design guidelines and explanations" also describes disinfection with ozone and ultraviolet rays. Furthermore, by storing temporarily wet-weather sewage is provided a pond tens of thousands m ^3, if the overflow has occurred by rainfall or more storage amount is a method of disinfection with chlorine disinfectant of the Proposed. Further, in recent years, a technique using a bromine-based disinfectant in addition to a chlorine-based disinfectant has been proposed.

For example, a wastewater disinfectant containing hypobromous acid or hypobromous acid, which is formed by mixing a bromide of a metal element with hypobromous acid or a salt thereof (Patent Document). 1), (A) a compound that generates hypobromous acid in water and (B) a compound that generates bromide ion in water have a pH of 5 to 5 in the presence of (C) hydroxycarboxylic acid and / or oxocarboxylic acid. A disinfectant containing hypobromous acid obtained by mixing in the aqueous system of No. 7 (Patent Document 2), (a) Hydrobromide, which releases bromine ions when dissolved in water, bromide. Bromide selected from sodium, potassium bromide, lithium bromide and zinc bromide, (b) 5,5-dialkyl-substituted hydantine and (c) hypobromous acid and / or a water-soluble salt thereof were treated. Add and mix at a molar ratio of (c) :( a) :( b) = 1: (0.2 to 3) :( 0.2 to 0.9) to the aqueous system to be subjected to (A) order in the aqueous system. A slime control method in an aqueous system (Patent Document 3), which comprises producing (B) N-monochloro-5,5-dialkyl-substituted hydantine with hypobromous acid and / or a water-soluble salt thereof, a bromide oxidizing agent in water. Or, a method for disinfecting water containing a stabilized hypobromous acid composition containing a reaction product of a bromine-based compound and a chlorine-based oxidizing agent, a sulfamic acid compound, and a chlorine-based oxidizing agent (Patent Document 4) has been proposed. Has been done.

In the method of Patent Document 1, when the drug is a liquid, decomposition proceeds with time, and the retention of the active ingredient and the storage stability of the disinfectant are insufficient as a disinfectant for sewage in rainy weather when it is not known when it is necessary. When the chemical is a solid such as powder, it is corrosive and dust is generated, which makes it more difficult to handle than a liquid, and it is difficult to quantitatively inject it and put it into practical use. Further, Patent Document 1 does not describe the mixing ratio of the metal bromide that maximizes the disinfecting effect and hypochlorous acid or a salt thereof.

In the method of Patent Document 2, when a component such as (C) hydroxycarboxylic acid and / or oxocarboxylic acid is used, not only the production of the drug becomes complicated due to the three-agent treatment, but also the organic component derived from the component (C) is used. It has disadvantages such as being added to the water to be treated and increasing the COD value.

Since the method of Patent Document 3 uses an expensive alkyl-substituted hydantoin, there is a problem that the disinfection cost becomes high.

In the method of Patent Document 4, by using sulfamic acid, not only the drug composition becomes complicated and the production becomes complicated, but also the raw material cost becomes high. Further, the addition of sulfamic acid has drawbacks such as a decrease in the concentration of the active ingredient acting as a disinfectant component. Further, when the disinfectant is prepared on-site, there are drawbacks such as an increase in the number of devices of the reaction device and the injection device, which leads to an increase in installation cost and difficulty in injection control.

Japanese Unexamined Patent Publication No. 2003-012425 Japanese Unexamined Patent Publication No. 2004-244372 JP-A-2009-226409 Japanese Unexamined Patent Publication No. 2016-209837

Conventionally, when a liquid with good handleability is used, hypochlorous acid and hypobromous acid are rich in reaction activity and deteriorate in a short time, so that a stabilizer has been indispensable. Further, when powder is used as a hypobromous acid compound or a hypochlorous acid compound, it is known that deterioration of the drug with time is unlikely to occur unlike the case of liquid, but dust is generated due to the use of fine particles. Therefore, injection control was difficult and practical application was difficult. In particular, oxidizing powders such as hypochlorous acid compounds have a high risk when an operator comes into contact with dust, and are extremely difficult to handle.

The present invention provides a disinfection method and apparatus that eliminates the drawbacks of conventional disinfection methods and adds a disinfectant with excellent handleability to ammonia nitrogen-containing wastewater to reduce Escherichia coli or coliform bacteria from ammonia nitrogen-containing wastewater. The purpose is to provide.

Means to solve problems

According to the present invention, there is provided a method and an apparatus for disinfecting wastewater containing ammoniacal nitrogen by adding a disinfectant having excellent handleability and long-term storage stability. Specific embodiments of the present invention are as follows.
[1] A predetermined amount of a solid hypochlorous acid source (B) is supplied to a drug (A) containing bromine ions, and the solid hypochlorous acid source (B) is dissolved in the drug (A). A disinfectant device for reducing coliforms or coliform bacteria from ammoniacal nitrogen-containing wastewater, comprising a means for preparing a disinfectant containing hypochlorous acid and adding the disinfectant to ammoniacal nitrogen-containing wastewater.
[2] The means for preparing the disinfectant and adding it to the ammoniacal nitrogen-containing wastewater includes an ejector or a line mixer, which is a disinfectant device for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to the above [1]. ..
[3] The means for preparing the disinfectant and adding it to the ammoniacal nitrogen-containing wastewater is a large-diameter portion that receives the solid hypochlorous acid source (B) and a small-diameter portion that connects to the inlet of the ejector or line mixer. A disinfectant device for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to the above [2], further comprising a conical container having.
[4] The ammoniacality according to any one of [1] to [3] above, further comprising means for preparing the drug (A) containing the bromine ion by supplying a predetermined amount of the bromine compound to the solvent. A disinfectant that reduces E. coli or coliforms from nitrogen-containing wastewater.
[5] The above-mentioned [4], wherein the ammoniacal nitrogen-containing wastewater to be treated is used as the solvent, and the means for preparing the drug (A) is further provided with a means for taking in the ammoniacal nitrogen-containing wastewater to be treated. A disinfectant that reduces E. coli or coliforms from the described ammonia-nitrogen-containing wastewater.
[6] A first sensor for measuring the water quality of ammoniacal nitrogen-containing wastewater before adding the disinfectant.
A second sensor that measures the water quality of ammoniacal nitrogen-containing wastewater after adding the disinfectant,
Based on the operator electrically connected to the first sensor and the second sensor, and the signal from the operator, the drug (A) and the solid hypochlorous acid source (B) A disinfectant device for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to any one of [1] to [5] above, which comprises a control means for controlling the mixing ratio of Escherichia coli.
[7] A predetermined amount of a solid hypochlorous acid source (B) is supplied and dissolved in a drug (A) containing bromine ions to prepare a disinfectant containing hypochlorous acid, which contains ammoniacal nitrogen. A disinfection method that reduces coliforms or coliforms from ammoniacal nitrogen-containing wastewater, including the step of adding to the wastewater.
[8] The disinfectant is added to the ammoniacal nitrogen-containing wastewater within a range of 1 second or more and less than 300 seconds after the solid hypochlorous acid source (B) is added to the drug (A). A disinfection method for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater described in 1.
[9] The bromine compound is one or more selected from sodium bromide, potassium bromide, ammonium bromide, calcium bromide, and dibromoisocyanuric acid.
The ammoniacality according to the above [7], wherein the solid hypochlorous acid source (B) is one or more selected from hypochlorite, dichloroisocyanuric acid or a salt thereof, trichloroisocyanuric acid or a salt thereof. Disinfection method for nitrogen-containing wastewater.
[10] The ammoniacal nitrogen according to any one of [7] to [9], further comprising a step of supplying a predetermined amount of a bromine compound to a solvent to prepare a drug (A) containing the bromine ion. A disinfection method that reduces E. coli or coliforms from contained wastewater.
[11] The disinfection method for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to the above [10], which uses the ammoniacal nitrogen-containing wastewater to be treated as the solvent.
[12] The water quality of the ammoniacal nitrogen-containing wastewater before adding the disinfectant was measured.
The water quality of the ammoniacal nitrogen-containing wastewater after adding the disinfectant was measured.
The step of controlling the mixing ratio of the bromine compound and the solid hypochlorous acid source (B) based on the difference in water quality of the ammoniacal nitrogen-containing wastewater before and after the addition of the disinfectant is further included. ] To [11]. The disinfection method for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to any one of [11].

Since the disinfectant method and apparatus of the present invention can prepare and add a disinfectant at the disinfection site of ammoniacal nitrogen-containing wastewater, it facilitates the handling of a dangerous substance, a hypochlorous acid source, and disinfectant. Ammonia nitrogen-containing wastewater can be disinfected before the decomposition of the active ingredient of.

It is explanatory drawing which shows the outline of the 1st Embodiment of the disinfection apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is explanatory drawing which shows the outline of the 2nd Embodiment of the disinfection apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is explanatory drawing which shows the outline of the 3rd Embodiment of the disinfection apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is explanatory drawing which shows the outline of the 4th Embodiment of the disinfection apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is schematic explanatory drawing which shows an example of the apparatus which quantitatively supplies the solid hypochlorous acid source (B) used in the disinfection apparatus of FIGS. 1 to 4.

Preferred embodiment

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 shows an outline of a first embodiment of the disinfecting apparatus for ammonia nitrogen-containing wastewater of the present invention. The disinfectant for ammonia nitrogen-containing wastewater of the present invention prepares a disinfectant containing hypochlorous acid by dissolving a predetermined amount of a solid hypochlorous acid source (B) in a drug (A) containing bromine ions. Immediately after, the disinfectant is added to the ammoniacal nitrogen-containing wastewater. As a means for adding the disinfectant to the ammoniacal nitrogen-containing wastewater, 1 second or more and less than 300 seconds, preferably 1 second after adding the solid hypochlorous acid source (B) to the agent (A) containing bromine ions. It is preferable to have a configuration in which the disinfectant can be added to the ammoniacal nitrogen-containing wastewater within a time of 60 seconds or less, and includes an ejector or a line mixer capable of dissolving the disinfectant and ejecting the disinfectant in a very short time. Is preferable.

The means for adding the disinfectant to the ammonia-containing nitrogen-containing wastewater is the mixing part 1 in which the solid hypochlorous acid source (B) is added to the medicine (A) and mixed, and the medicine (A) is received from the mixing part 1. ) To dissolve the hypochlorous acid source (B) to prepare the disinfectant, the disinfectant preparation department 2, the first line 3 to supply the disinfectant (A) to the disinfectant preparation department 2, and the disinfectant preparation department 2. The disinfectant supply line 4 for supplying the disinfectant immediately after is supplied to the ammoniacal nitrogen-containing wastewater (hereinafter, also referred to as “water to be treated”) is provided.

As the disinfectant preparation unit 2, an ejector or a line mixer can be preferably mentioned. The ejector is a device that sucks in and discharges a low-pressure fluid using the force of a high-pressure fluid. It sucks a powdery hypochlorous acid source (B) into the ejector and flows into the ejector (A). ) Can be efficiently dissolved in a short time, and the prepared disinfectant can be sprayed onto the water to be treated. The line mixer is a high-pressure agitator installed in the piping. A powdery hypochlorous acid source (B) is added to the chemical (A) in the line mixer, and the mixture is stirred under high pressure to the water to be treated. Can be transferred quickly. By using an ejector or a line mixer, the dissolution of the solid hypochlorous acid source (B) in the drug (A) is promoted, and the preparation of the disinfectant to the addition to the ammonia nitrogen-containing wastewater can be performed in a short time. Therefore, the active ingredient of the disinfectant works sufficiently without being attenuated. In addition, since it is possible to prevent blockage due to accumulation of undissolved solid in the pipe, stable continuous operation is possible.

As the mixing portion 1, it is preferable to use a conical container having a large diameter portion 1a for receiving the solid hypochlorous acid source (B) and a small diameter portion 1b connected to the inlet 2a of the disinfectant preparation unit 2. it can. The first line 3 is preferably tangentially connected to the upper portion 1a of the side wall of the conical container so that the drug (A) can be supplied as a whirlpool along the tapered inner surface of the conical container.

FIG. 2 shows an outline of a second embodiment of the disinfection device of the present invention. The second embodiment has the same configuration as the first embodiment except that it further includes means for preparing the drug (A). The same components as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, as means for preparing the drug (A), the bromine compound storage tank 5 for storing the bromine compound, the liquid storage tank 6 for storing the liquid for dissolving or diluting the bromine compound, and the bromine compound from the bromine compound storage tank 5 A second line 7 for supplying the liquid and a third line 8 for supplying the liquid from the liquid storage tank 6 and receiving the bromine compound are provided. The third line 8 is connected to the disinfectant preparation unit 2. The first line 3 is connected to the third line 8 on the upstream side of the third line 8 from the connection portion with the disinfectant preparation unit 2.

In the second embodiment, the bromine compound stored in the bromine compound storage tank 5 may be a solid bromine compound or a liquid containing bromine ions. The liquid stored in the liquid storage tank 6 is not particularly limited as long as it can dissolve a solid bromine compound or dilute a liquid containing bromine ions, and tap water, well water, industrial water, rainwater, and sewage. , Primary treated water from sewage treatment plant, sewage after biological treatment, discharged water after advanced treatment, simple treated water, sand sedimentation treated water, treated water from human waste treatment plant, ammonia nitrogen to be treated in the present invention It can be any liquid such as drainage.

FIG. 3 shows an outline of a third embodiment of the disinfection device of the present invention. The third embodiment has the same configuration as the first embodiment except that it further includes a control means for controlling the mixing ratio of the drug (A) and the solid hypochlorous acid source (B). The same components as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The control means in the third embodiment is a first sensor 111 for measuring the water quality of the ammoniacal nitrogen-containing wastewater before the disinfectant is added, and a first sensor 111 for measuring the water quality of the ammoniacal nitrogen-containing wastewater after the disinfectant is added. Agent (A) and solid hypochlorous acid source based on signals from sensor 112 of 2, operator 113 electrically connected to first sensor 111 and second sensor 112, and operator 113. The control means 114 and 115 for controlling the mixing ratio with (B) are provided.

As the first sensor 111, a sensor capable of measuring turbidity, ammoniacal nitrogen concentration, electric conductivity and the like can be preferably used. As the second sensor 112, a sensor capable of measuring the residual halogen concentration, the ammoniacal nitrogen concentration, the electric conductivity and the like can be preferably used.

The operator 113 takes into account not only water quality information from the first sensor 111 and the second sensor 112 but also information such as rainfall amount, rainfall time, and rainwater pump operating time, and controls signals to the control means 114 and 115. May be sent.

The control means 114 is not particularly limited as long as it is electrically connected to the operator 113 and can control the supply of the drug (A), and is provided, for example, in the first line 3 for supplying the drug (A). A control valve, a pump, or the like can be used. The control means 115 is not particularly limited as long as it is electrically connected to the operator 113 and can control the supply of the solid hypochlorous acid source (B), for example, the solid hypochlorous acid source (B). ) Quantitative supply mechanism and the like can be used.

FIG. 4 shows an outline of a fourth embodiment of the disinfection device of the present invention. The fourth embodiment has the same configuration as the second embodiment except that it further includes a control means for controlling the mixing ratio of the drug (A) and the solid hypochlorous acid source (B). The same components as those of the second embodiment shown in FIG. 2 are designated by the same reference numerals and description thereof will be omitted, and the same components of the control means shown in FIG. 3 will be designated by the same reference numerals and description thereof will be omitted.

In the fourth embodiment, the control means 114 is a control valve or pump that controls the supply of the bromine compound from the bromine compound storage tank 5 and / or the supply of the liquid from the liquid storage tank 6, or the first line 3 and the second line. Control valves, pumps, and the like provided in 1 or more of 7 and the 3rd line 8 can be used.

In the disinfecting apparatus shown in FIGS. 1 to 4, the apparatus for quantitatively supplying the solid hypochlorous acid source (B) to the drug (A) is not particularly limited, and a normal powder quantitative supply apparatus can be used. It is preferable that the powder quantitative supply device is capable of preventing solidification due to consolidation of the powder and supplying the required amount of powder when necessary without the operator touching the powder. For example, a powder flow tank 11 that supplies compressed air from the bottom of the tank shown in FIG. 5 to store powder while maintaining a flow bed of powder, and a powder provided in the lower stage of the powder flow tank 11. A powder quantitative supply device including the body quantitative supply chamber 12 can be preferably used.

As an example, the powder flow tank 11 shown in FIG. 5 has a compressed air introduction port 13 at the bottom. In order to prevent the powder from getting wet or solidifying inside the tank, compressed air is blown in periodically to make the powder in a fluid state. A rotary blade 14 is provided in the lower part of the powder flow tank 11. An opening 14a is provided at the outer peripheral end of the rotary blade 14, and a predetermined amount of powder is dropped into the powder fixed quantity supply chamber 12. The powder quantitative supply chamber 12 has a powder outlet 12a on the bottom surface, and supplies the quantitative powder to the mixing unit 1 for preparing the disinfectant shown in FIGS. 1 to 4. A rotary table 15 is provided at the lower part of the powder metering supply chamber 12. On the outer circumference of the rotary table, a plurality of measuring chambers 15a having open upper and lower surfaces are provided at predetermined intervals. On the upper surface of the rotary table 15, a fray plate (not shown) that comes into contact with the upper surface of the measuring chamber 15a and measures a predetermined amount is provided. When the rotary table 15 rotates while in contact with the fixed fray plate and the measuring chamber 15a reaches the position of the powder outlet 12a, the predetermined amount of powder dropped into the measuring chamber 15a is mixed from the powder outlet 12a. It is supplied to the part 1.

Next, the method for disinfecting the ammoniacal nitrogen-containing wastewater of the present invention will be described.
In the method for disinfecting ammoniacal nitrogen-containing wastewater of the present invention, a predetermined amount of a solid hypochlorous acid source (B) is supplied to a chemical (A) containing bromine ions to dissolve it, and the disinfectant containing hypochlorous acid is dissolved. And the prepared disinfectant is added to the ammoniacal nitrogen-containing wastewater.

The drug (A) containing bromine ions may be an aqueous solution containing bromine ions prepared in advance, or a liquid containing bromine ions prepared by dissolving a bromine compound in the field. The bromine compound is preferably one or more selected from sodium bromide, potassium bromide, ammonium bromide, calcium bromide, and dibromoisocyanuric acid. Liquids that dissolve bromine compounds or dilute bromine ion aqueous solutions include tap water, well water, industrial water, rainwater, sewage, primary treated water from sewage treatment plants, sewage after biological treatment, and discharged water after advanced treatment. , Simple treated water, sand sedimentation treated water, treated water from a sewage treatment plant, any liquid such as ammoniacal nitrogen-containing sewage to be treated in the present invention can be preferably used.

The solid hypochlorous acid source (B) is preferably one or more selected from hypochlorite, dichloroisocyanuric acid or a salt thereof, trichloroisocyanuric acid or a salt thereof. As the hypochlorite, sodium hypochlorite, calcium hypochlorite and the like can be preferably mentioned, and powders such as bleached powder or highly bleached powder can be used. As the salt of dichloroisocyanuric acid, powders or granules such as sodium dichloroisocyanurate, sodium dichloroisocyanurate dihydrate, potassium dichloroisocyanuric acid, and ammonium dichloroisocyanurate can be preferably mentioned. As the trichloroisocyanurate, powders or granules such as sodium trichloroisocyanurate and potassium trichloroisocyanurate can be preferably mentioned.

The time until the disinfectant is prepared and added to the ammoniacal nitrogen-containing wastewater is in the range of 1 second or more and less than 300 seconds after the addition of the solid hypochlorous acid source (B) to the drug (A), preferably. A range of 1 second or more and 60 seconds or less is desirable. If it is less than 1 second, the disinfecting effect is insufficient, and if it exceeds 300 seconds, the reaction of the drug may be terminated and the disinfecting effect may be attenuated.

The method for disinfecting ammonia nitrogen-containing wastewater of the present invention measures the water quality of ammonia nitrogen-containing wastewater before adding a disinfectant, measures the water quality of ammonia nitrogen-containing wastewater after adding a disinfectant, and disinfects. Further including a step of controlling the mixing ratio of the bromine-containing drug (A) and the solid hypochlorous acid source (B) based on the difference in water quality of the ammoniacal nitrogen-containing wastewater before and after the drug is added. Is preferable. Ammonium ion concentration, turbidity, conductivity and the like are preferable as the water quality that can be used as an index for controlling the mixing ratio of the drug (A) containing bromine ions and the solid hypochlorous acid source (B). Can be mentioned. The ammonium ion concentration can be measured using a commercially available densitometer such as an ion electrode type continuous measuring device (AISE _SC manufactured by HACH). It is also possible to estimate the ammonium ion concentration based on the results of water quality analysis of sewage in rainy weather in the past, based on operating conditions such as the elapsed time from the start of discharge and the amount of discharged water.

Using the residual free halogen concentration as an index, the disinfecting effects of disinfectants on pure water due to differences in the state of each drug and the order of addition were compared.
(Disinfectant 1) One second after adding 11.2 ml of a 40% potassium bromide aqueous solution to 1 L of pure water, 2.7 g of sodium dichloroisocyanurate granules was added to prepare a disinfectant, and 30 seconds later, 60 The residual free halogen concentration was measured after seconds and 90 seconds.
(Disinfectant 2) After 1 second of adding 2.7 g of sodium dichloroisocyanurate granules to 1 L of pure water, 11.2 ml of a 40% potassium bromide aqueous solution was added to prepare a disinfectant, and 30 seconds and 90 seconds later. Later, the residual free halogen concentration was measured.
(Disinfectant 3) A disinfectant was prepared by mixing 4.48 g of solid potassium bromide and 2.7 g of sodium dichloroisocyanurate granules, and this disinfectant was added to 1 L of pure water 30 seconds later and After 90 seconds, the residual free halogen concentration was measured.
(Disinfectant 4) A disinfectant was prepared by mixing 11.2 ml of a 40% potassium bromide aqueous solution and 2.7 g of sodium dichloroisocyanurate granules, and this disinfectant was added to 1 L of pure water and remained after 60 seconds. The free halogen concentration was measured.

In the disinfectants 1 to 4, the molar ratio of potassium bromide to sodium dichloroisocyanurate was set to 1: 1.5, and the disinfectant injection rate was set to 8 mg / L as Cl _{2 in} terms of effective chlorine concentration. Was constantly stirred at 600 rpm / min. The residual free halogen value was measured by collecting water from the middle layer of each liquid using a micropipette. The results are shown in Table 1.

With the disinfectants 1 to 3, the residual free halogen concentration after 90 seconds was almost the same, and it is considered that there is no significant difference in the disinfecting effect. However, the disinfectant 4 in which solid sodium dichloroisocyanurate and liquid potassium bromide were mixed in advance had a concentration of less than half that of Example 1 after 60 seconds, and it is considered that the disinfecting effect was drastically reduced. ..

Next, 7.49 g of ammonium chloride (2520 mg / L as NH4) was added to pure water as a liquid to be treated, and after confirming that the solution was completely dissolved, the drug was immediately added, and after 30 seconds and 60. Table 2 shows the results of measuring the residual free halogen concentration after seconds.

In Example 1, 11.2 mL of a 40% potassium bromide aqueous solution was first added to the liquid to be treated, and then 2.7 g of sodium dichloroisocyanurate granules was added to the liquid to be treated.
In Comparative Example 1, 2.7 g of sodium dichloroisocyanurate granules was first added to the liquid to be treated, and then 11.2 mL of a 40% potassium bromide aqueous solution was added to the liquid to be treated.

In both Example 1 and Comparative Example 1, the molar ratio of potassium bromide to sodium dichloroisocyanurate was set to 1: 1.5, and the disinfectant injection rate was set to 8 mg / L as Cl _{2 in} terms of effective chlorine concentration. When each drug was added, stirring was constantly performed at 600 rpm / min. The residual halogen concentration was measured by collecting water from the middle layer of each liquid using a micropipette.

In Example 1, the residual free halogen concentration was high after 30 seconds and 60 seconds, and the disinfecting effect was maintained, whereas in Comparative Example 1, it drastically decreased to 180 mg / L after 60 seconds, and the disinfecting effect was maintained. It is considered that it has not been done. The order of chemical addition to pure water did not show a significant difference in the residual free halogen concentration as an index of disinfecting effect, but it was confirmed that the order of chemical addition to ammonium-containing water caused a significant difference in maintaining the disinfecting effect. It was.

Further, ammonium chloride and a bacterial solution containing coliform bacteria were added to 1 L of pure water to prepare simulated ammonium ion-containing wastewater, and the effect of the chemical addition order was confirmed.

In Example 2, 1.0 g of solid potassium bromide was added to 100 mL of simulated ammonium ion-containing wastewater to prepare 1% simulated potassium bromide-containing wastewater, followed by 8.54 mg of sodium dichloroisocyanurate granules with a 1% odor. A drug prepared by adding to 0.92 mL of simulated potassium bromide-containing wastewater was added to 1 L of simulated wastewater containing simulated ammonium ions and Escherichia coli.

In Comparative Example 2, 8.54 mg of sodium dichloroisocyanurate granules was first added to 0.92 mL of simulated ammonium ion-containing wastewater, and then 9.2 mg of solid potassium bromide was added to 0.92 mL of simulated ammonium ion-containing wastewater. The drug prepared in the above was added to 1 L of simulated wastewater containing simulated ammonium ions and Escherichia coli.

In both Example 2 and Comparative Example 2, the molar ratio of potassium bromide to sodium dichloroisocyanurate was set to 1: 1 and the disinfectant injection rate was set to 8 mg / L in terms of effective chlorine concentration, and when each drug was added. Constant stirring was performed at 150 rpm / min. The residual halogen value was measured 60 seconds after the addition of the drug, by collecting water from the middle layer of each liquid using a micropipette. The number of coliforms was measured by the method described in Attached Table 1 of the Ministerial Ordinance on the Method for Testing the Quality of Sewage (December 17, 1958, Ministry of Health and Welfare / Ministry of Construction Ordinance No. 1). The results are shown in Table 3.

In Example 2, the residual free halogen concentration 60 seconds after the addition of the disinfectant was 2.9 mg / L, and no coliform bacteria were detected. In Comparative Example 2, the residual free halogen concentration 60 seconds after the addition of the disinfectant was 1.6 mg / L, and coliform bacteria were detected at 630 cfu / ml. Although the number of coliform bacteria in both Example 2 and Comparative Example 2 satisfied the discharge standard value, the disinfecting effect of Example 2 in which the potassium bromide solution was added first and then the granules of sodium dichloroisocyanurate were added. It can be confirmed that it is better. The present invention is particularly useful for simple disinfection of rainy sewage and the like that are discharged into public water bodies without being sufficiently treated.

Claims (12)

A predetermined amount of a solid hypochlorous acid source (B) is supplied to the drug (A) containing bromine ions, and the solid hypochlorous acid source (B) is dissolved in the drug (A). A disinfectant that prepares a disinfectant containing hypochlorous acid and adds the disinfectant to ammonia nitrogen-containing wastewater to reduce coliforms or coliforms from ammonia nitrogen-containing wastewater. The means for preparing the disinfectant and adding it to the ammoniacal nitrogen-containing wastewater is a disinfectant device including an ejector or a line mixer, which reduces Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to claim 1. The means for preparing the disinfectant and adding it to the ammoniacal nitrogen-containing wastewater has a large diameter portion that receives the solid hypochlorous acid source (B) and a small diameter portion that connects to the inlet of the ejector or line mixer. The disinfectant device for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to claim 2, further comprising a conical container. Escherichia coli or Escherichia coli from the ammoniacal nitrogen-containing wastewater according to any one of claims 1 to 3, further comprising means for preparing the drug (A) containing the bromine ion by supplying a predetermined amount of a bromine compound to the solvent. A disinfectant that reduces coliforms. The ammoniacality according to claim 4, wherein the ammoniacal nitrogen-containing wastewater to be treated is used as the solvent, and the means for preparing the drug (A) is further provided with a means for taking in the ammoniacal nitrogen-containing wastewater to be treated. A disinfectant that reduces E. coli or coliforms from nitrogen-containing wastewater. A first sensor that measures the water quality of ammoniacal nitrogen-containing wastewater before adding the disinfectant,
A second sensor that measures the water quality of ammoniacal nitrogen-containing wastewater after adding the disinfectant,
Based on the operator electrically connected to the first sensor and the second sensor, and the signal from the operator, the drug (A) and the solid hypochlorous acid source (B) A disinfectant device for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to any one of claims 1 to 5, further comprising a control means for controlling the mixing ratio of Escherichia coli. A predetermined amount of a solid hypochlorous acid source (B) is supplied to the drug (A) containing bromine ions to dissolve it, a disinfectant containing hypochlorous acid is prepared, and added to the ammoniacal nitrogen-containing wastewater. A disinfection method for reducing E. coli or coliforms from ammoniacal nitrogen-containing wastewater, including the step of The ammonia according to claim 7, wherein the disinfectant is added to the ammoniacal nitrogen-containing wastewater within a range of 1 second or more and less than 300 seconds after the solid hypochlorous acid source (B) is added to the agent (A). A disinfection method that reduces E. coli or coliforms from nitrogen-containing wastewater. The bromine compound is one or more selected from sodium bromide, potassium bromide, ammonium bromide, calcium bromide, and dibromoisocyanuric acid.
The ammoniacal nitrogen according to claim 7, wherein the solid hypochlorous acid source (B) is at least one selected from hypochlorite, dichloroisocyanuric acid or a salt thereof, trichloroisocyanuric acid or a salt thereof. A method of reducing E. coli or coliforms from contained wastewater. Escherichia coli or coliforms from the ammoniacal nitrogen-containing wastewater according to any one of claims 7 to 9, further comprising the step of supplying a predetermined amount of a bromine compound to a solvent to prepare the drug (A) containing the bromine ion. Disinfection method to reduce flock. The disinfection method for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to claim 10, wherein the ammoniacal nitrogen-containing wastewater to be treated is used as the solvent. The water quality of the ammoniacal nitrogen-containing wastewater before adding the disinfectant was measured.
The water quality of the ammoniacal nitrogen-containing wastewater after adding the disinfectant was measured.
7. A step of controlling the mixing ratio of the bromine compound and the solid hypochlorous acid source (B) based on the difference in water quality of the ammoniacal nitrogen-containing wastewater before and after the addition of the disinfectant is included. The disinfection method for reducing Escherichia coli or coliform bacteria from the ammoniacal nitrogen-containing wastewater according to any one of 1 to 11.

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