Method for treating raw water containing hardly decomposable substance

Abstract

A method for treating a raw water containing a hardly decomposable substance, which comprises the following steps: a step (B) of adding an adsorbing agent to a raw water containing a hardly decomposable substance (a raw water to be treated) to allow said adsorbing agent to adsorb the hardly decomposable substance (an adsorption treatment step), a step (C) of separating a permeated liquid by the use of a filtration film, to concentrate the adsorbing agent having absorbed said hardly decomposable substance (a film filtration treatment step), and (D) a step of chemically decomposing the hardly decomposable substance being adsorbed in the concentrated adsorbing agent by a peroxide, without the operation for desorption from said adsorbing agent (a chemical decomposition step), and, by the above steps, concentrates hardly decomposable substances such as dioxins contained in a contaminated water (the raw water to be treated) and converts the hardly decomposable substances to harmless substances. The above method can be applied also to a raw water containing a reducing substance such as a hydrogensulfite for neutralizing free chlorine, the application thereof is not limited by the properties of hardly decomposable substances being contained, and also it allows conversion of hardly decomposable substances to harmless ones with good efficiency at a low cost.

Description

Technical field

[0001] The present invention relates to a method for treating water containing hardly decomposable substances such as dioxenes and other endocrine disrupting substances. Background technique

[0002] In 1999, Japan formulated a special treatment method for diene countermeasures. In this special treatment method for diene countermeasures, the emission standard of dienes is set to 10pg-TEQ / L or less. On the other hand, waste water from incinerator disintegration works, industrial waste water discharged from specific facilities, and a part of soil leaching water sometimes contain high concentrations of diolefins that significantly exceed this standard. Therefore, it is very hopeful that developments can be developed to reduce them. Treatment or removal technology.

[0003] In addition, endocrine disrupting substances such as bisphenols (also called environmental hormones and endocrine disrupting chemicals) other than diolefins, and various organic chlorides represent...

Examples

Embodiment approach

[0224] For example in Figure 4 In the embodiment of (a), an adsorbent is added to the water (raw water) containing hardly decomposable substances ((B-1) adsorption treatment step), and separated into a concentrate and a permeate by membrane filtration ((C-1) membrane Filtration treatment process). Regarding the concentrate, it is processed in the above-mentioned (D) chemical decomposition step. After further adding an adsorbent to the permeate ((B-2) adsorption treatment step), membrane filtration is performed again ((C-2) membrane filtration treatment step); the concentrate that has not passed through the filter membrane is returned In the (B-1) adsorption treatment step, since the permeate is below the discharge standard, it can be discharged to the outside as discharged water.

[0225] in Figure 4 In the embodiment of (b), by providing the (B) adsorption treatment step once and the (C) membrane filtration treatment step twice, a more economical system can be formed.

[0226] ...

Embodiment 1

[0249] Example 1 (refer to Figure 6)

[0250] (B) Adsorption treatment process

[0251] Put the raw water (dioxene concentration 6500pg-TEQ / L) into the adsorption tank with a residence time of 1 hour, add 1000ppm silica bath clay as an adsorbent, and stir to make it adsorb.

[0252] (C) Membrane filtration treatment process

[0253] Use an ultrafiltration membrane (hollow fiber type, molecular weight cut-off of 150,000) to filter the water with the above adsorbent, and add (return) a part of the liquid that fails to pass through the ultrafiltration membrane to the raw water with the adsorbent. Make it pass completely under 0.3MPa operating pressure. The permeate at this time was 2.5pg-TEQ / L, which was below the emission standard value (10pg-TEQ / L). As the washing water, the amount of permeate that is four times the amount of the permeate of the ultrafiltration membrane was backwashed for 1 minute, and the backwash was used as a concentrate (slurry).

[0254] (D) Chemical decomposi...

Embodiment 2

[0256] Example 2 (Refer to Figure 7)

[0257] (A) Membrane concentration treatment process

[0258] The raw water (dioxene concentration 6500pg-TEQ / L) is filtered by reverse osmosis membrane (spiral type, 95% sodium chloride rejection rate). A part of the liquid component (concentrated water) that failed to pass through the reverse osmosis membrane is added (returned) to the raw water, and filtered under an operating pressure of 1 MPa or more. Use 2 / 3 of the processing volume as the permeate. At this time, the concentration of dioxene in the permeate is 1pg-TEQ / L, which is below the emission standard value (10pg-TEQ / L).

[0259] (B) Adsorption treatment process

[0260] The concentrated water of 1 / 3 of the treatment amount obtained in the step (A) was put into an adsorption tank for a residence time of 1 hour in the same manner as in Example 1, 2000 ppm of activated clay was added as an adsorbent, and the mixture was stirred and adsorbed.

[0261] (C) Membrane filtration treatment...

Technical field

[0001] The present invention relates to a method for treating water containing hardly decomposable substances such as dioxenes and other endocrine disrupting substances. Background technique

[0002] In 1999, Japan formulated a special treatment method for diene countermeasures. In this special treatment method for diene countermeasures, the emission standard of dienes is set to 10pg-TEQ / L or less. On the other hand, waste water from incinerator disintegration works, industrial waste water discharged from specific facilities, and a part of soil leaching water sometimes contain high concentrations of diolefins that significantly exceed this standard. Therefore, it is very hopeful that developments can be developed to reduce them. Treatment or removal technology.

[0003] In addition, endocrine disrupting substances such as bisphenols (also called environmental hormones and endocrine disrupting chemicals) other than diolefins, and various organic chlorides represent...

Examples

Embodiment approach

[0224] For example in Figure 4 In the embodiment of (a), an adsorbent is added to the water (raw water) containing hardly decomposable substances ((B-1) adsorption treatment step), and separated into a concentrate and a permeate by membrane filtration ((C-1) membrane Filtration treatment process). Regarding the concentrate, it is processed in the above-mentioned (D) chemical decomposition step. After further adding an adsorbent to the permeate ((B-2) adsorption treatment step), membrane filtration is performed again ((C-2) membrane filtration treatment step); the concentrate that has not passed through the filter membrane is returned In the (B-1) adsorption treatment step, since the permeate is below the discharge standard, it can be discharged to the outside as discharged water.

[0225] in Figure 4 In the embodiment of (b), by providing the (B) adsorption treatment step once and the (C) membrane filtration treatment step twice, a more economical system can be formed.

[0226] ...

Embodiment 1

[0249] Example 1 (refer to Figure 6)

[0250] (B) Adsorption treatment process

[0251] Put the raw water (dioxene concentration 6500pg-TEQ / L) into the adsorption tank with a residence time of 1 hour, add 1000ppm silica bath clay as an adsorbent, and stir to make it adsorb.

[0252] (C) Membrane filtration treatment process

[0253] Use an ultrafiltration membrane (hollow fiber type, molecular weight cut-off of 150,000) to filter the water with the above adsorbent, and add (return) a part of the liquid that fails to pass through the ultrafiltration membrane to the raw water with the adsorbent. Make it pass completely under 0.3MPa operating pressure. The permeate at this time was 2.5pg-TEQ / L, which was below the emission standard value (10pg-TEQ / L). As the washing water, the amount of permeate that is four times the amount of the permeate of the ultrafiltration membrane was backwashed for 1 minute, and the backwash was used as a concentrate (slurry).

[0254] (D) Chemical decomposi...

Embodiment 2

[0256] Example 2 (Refer to Figure 7)

[0257] (A) Membrane concentration treatment process

[0258] The raw water (dioxene concentration 6500pg-TEQ / L) is filtered by reverse osmosis membrane (spiral type, 95% sodium chloride rejection rate). A part of the liquid component (concentrated water) that failed to pass through the reverse osmosis membrane is added (returned) to the raw water, and filtered under an operating pressure of 1 MPa or more. Use 2 / 3 of the processing volume as the permeate. At this time, the concentration of dioxene in the permeate is 1pg-TEQ / L, which is below the emission standard value (10pg-TEQ / L).

[0259] (B) Adsorption treatment process

[0260] The concentrated water of 1 / 3 of the treatment amount obtained in the step (A) was put into an adsorption tank for a residence time of 1 hour in the same manner as in Example 1, 2000 ppm of activated clay was added as an adsorbent, and the mixture was stirred and adsorbed.

[0261] (C) Membrane filtration treatment...

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