JP2009189992A - Method for recovering and removing brominated flame retardant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering and removing a brominated flame retardant, in which particulate HBCD (hexabromocyclododecane) in a waste dyeing liquid colored by a dyeing agent can be recovered as a reusable shape, the waste dyeing liquid can be decolorized, dissolved HBCD can be removed and the load/cost in a waste water treatment step can be reduced. <P>SOLUTION: The method for recovering and removing the brominated flame retardant comprises: a recovery step 10 of using a membrane filtration means 11 for filtering the waste dyeing liquid by using a filtration membrane; and a removal step 20 including a flocculation processing means 21 for flocculating fine particles contained in the filtrate obtained by the membrane filtration means 11 and coarsening the obtained flocks and an adsorption means 22 for adsorbing the brominated flame retardant which is dissolved in a supernatant liquid after flocculation obtained by the flocculation means 21, on an adsorbing material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for recovering and removing a brominated flame retardant contained in a dyeing waste liquid.

  From the viewpoint of fire prevention measures, electrical appliances or clothing, textile products, interior products, plastic products, etc. used in everyday civic life spaces are hexabromocyclododecane (hereinafter, referred to as `` Products '') in order to suppress product ignition and combustion. (Abbreviated as HBCD), brominated diphenyl ethers, tetrabrominated bisphenol A and other brominated flame retardants are added to produce a product. Originally, these brominated flame retardants have been used for the purpose of ensuring the safety of life by suppressing fire and fire spread, and are indispensable for providing a safe living environment. However, some brominated flame retardants have been reported on data related to bioaccumulation, persistence, and toxicity based on endocrine disrupting effects, and risk management is required. In fact, in Europe and the United States, especially in the EU countries, regulations regarding the production, use or disposal of some brominated flame retardants have already been established, and EU-RoHS “EU-Specific Hazardous Substances Usage Regulations” has been presented. In Japan as well, discussions increased with the results of research on brominated dioxins and brominated flame retardants (hereinafter referred to as brominated residual organic pollutants, Br-POPs) announced by the Ministry of the Environment in the past, It is in a regulated direction.

In the risk management of brominated flame retardants widely used in various products in the living space, the risk of environmental release during production and disposal and the risk of by-product of harmful substances in the event of fire are more problematic than exposure during product use. Has been. In particular, regarding the environmental release risk during manufacturing and disposal, it is easy to identify the source of the textile / dyeing industry, plastic manufacturing process, electrical appliance manufacturing factory, recycling facility, incineration facility, etc. Therefore, it is easy to take effective measures. Therefore, risk management of wastewater, exhaust gas, and waste in these facilities will be an immediate issue.
According to a survey by the Ministry of the Environment, relatively high concentrations of brominated POPs such as brominated flame retardants have been detected in the effluent of wastewater treatment facilities in the textile and dyeing industries. Countermeasures are desired. Also, in terms of manufacturing costs, the efficiency of adding brominated flame retardants such as HBCD used in these manufacturing facilities to the products is about 50%, and about half of the brominated flame retardants used as manufacturing raw materials are discarded. Therefore, the development of technology to collect and recycle these raw materials is beneficial.
Conventionally, activated sludge method and coagulation sedimentation method are mainly used as treatment methods for colored wastewater discharged from the textile and dyeing industries, etc., and general treatment systems include biological treatment tanks, coagulation sedimentation tanks, activated carbon towers. It is processed in combination. However, in the treatment of these colored wastewaters, a large amount of chemicals is generally required for the decolorization of the colored wastewater, and a large amount of biological treatment and coagulated sediment sludge are discharged as industrial waste.
On the other hand, JP-A-11-10142 below provides a wastewater treatment method using a photocatalyst and a membrane treatment for the purpose of decolorization.
Japanese Patent Laid-Open No. 11-10142

The wastewater treatment method disclosed in Patent Document 1 has an advantage that the wastewater can be easily decolorized and discharged as environmental water without a sense of pollution.
However, the treatment of colored wastewater discharged from the textile / dyeing industry has a problem that the light transmittance is insufficient and sufficient treatment cannot be performed. Furthermore, the wastewater treatment method shown in Patent Document 1 is aimed at purifying wastewater, and has a problem that it is not a system that can recover useful substances (hereinafter referred to as particulate HBCD) in wastewater.

  Therefore, the present invention solves the conventional problems, collects particulate HBCD in the dyeing waste liquid accompanied by coloring with the dyeing agent in a reusable form, decolorizes the waste water, and removes dissolved HBCD, It is an object to provide a method for recovering and removing a brominated flame retardant that can reduce the load and cost of the wastewater treatment process.

In order to achieve the above object, the method for recovering and removing a brominated flame retardant of the present invention is a method for recovering and removing a brominated flame retardant contained in a dyeing waste liquid from the dyeing waste liquid, wherein the brominated flame retardant is used from the dyeing waste liquid. A recovery step for recovering the waste dye for reuse, and a removal step for removing the brominated flame retardant from the waste dye solution for disposal, and the recovery step is a membrane filtration process for filtering the waste dye solution using a filtration membrane. And the removing step includes aggregating treatment means for agglomerating and coarsening fine particles contained in the filtrate filtered by the membrane filtration treatment means, and a supernatant liquid after aggregating treatment generated by the aggregating treatment means. The first feature is that it has an adsorption treatment means for adsorbing the brominated flame retardant to be adsorbed on the adsorbent.
Moreover, in addition to the said 1st characteristic, the collection | recovery / removal method of the brominated flame retardant of this invention is the 2nd characteristic that the filtration membrane in a membrane filtration process means consists of 0.1-1.0 micrometer pore diameter. It is said.

According to the recovery / removal method of brominated flame retardant according to claim 1, a recovery step of recovering the brominated flame retardant from the dye waste liquid for reuse, and removal of the brominated flame retardant from the dye waste liquid for disposal Therefore, the brominated flame retardant contained in the dyeing waste liquid can be effectively recovered and reused. Moreover, the brominated flame retardant remaining in the dyeing waste liquid can be effectively removed.
Moreover, since it has the structure which has the membrane filtration process means which filters a dyeing waste liquid using a filtration membrane, the collection | recovery process can collect the brominated flame retardant contained in a dyeing waste liquid effectively.
In addition, the removing step includes a coagulation treatment means for agglomerating and coarsening fine particles contained in the filtrate filtered by the membrane filtration treatment means, and a brominated flame retardant dissolved in the supernatant liquid after the aggregation treatment produced by the aggregation treatment means. Since the adsorbent is adsorbed on the adsorbent, the fine particles contained in the filtrate can be effectively aggregated and coarsened. Therefore, the fine particles can be reliably recovered. Moreover, the brominated flame retardant which melt | dissolves in a supernatant liquid can be made to adsorb | suck to an adsorbent reliably.

  According to the recovery / removal method of the brominated flame retardant according to claim 2, since the filtration membrane in the membrane filtration means has a constitution having a pore diameter of 0.1 to 1.0 μm, bromine contained in the dyeing waste liquid. The flame retardant can be concentrated and recovered. Therefore, the flame retardant can be recovered in a reusable state.

A method for recovering and removing a brominated flame retardant according to an embodiment of the present invention will be described with reference to the following drawings.
FIG. 1 is an explanatory diagram showing a system of a method for recovering and removing a brominated flame retardant according to an embodiment of the present invention. FIG. 2 is a graph showing an adsorption isotherm of dissolved HBCD by macropore activated carbon in Example 3 of the present invention.

First, a brominated flame retardant recovery / removal system 1 according to an embodiment of the present invention will be described with reference to FIG.
The brominated flame retardant recovery / removal system 1 according to the present invention includes a recovery step 10 and a removal step 20.

The recovery step 10 is a step for recovering the brominated flame retardant contained in the dyeing waste liquid in a reusable manner, and has a membrane filtration processing means 11.
The membrane filtration processing means 11 is a processing means for filtering the dyeing waste liquid with a filtration membrane.
A microfilter membrane (hereinafter abbreviated as MF membrane) is used as the filtration membrane, and filtration is performed by passing the dyed waste liquid through the MF membrane module in a cross-flow manner.

The particulate HBCD collected in the MF membrane is periodically desorbed from the MF membrane by backwashing the MF membrane with tap water or treated water, and the backwash water tank as a high concentration particulate HBCD solution together with the backwash solution. To be discharged. The discharged high-concentration particulate HBCD liquid is reused as a flame retardant added to the fiber.
The pore size of the MF membrane may be any as long as it is about 0.05 to 10 μm, but is preferably 0.1 to 1.0 μm. By setting the thickness to 0.1 to 1.0 μm, the brominated flame retardant contained in the dyeing waste liquid can be concentrated and recovered. Therefore, the flame retardant can be recovered in a reusable state. The material may be any material such as polypropylene, polyester, etc. as long as it is normally used as an MF film.
By using the MF membrane in this way, it becomes possible to concentrate and collect particulate HBCD contained in the staining waste liquid. Therefore, the flame retardant contained in the dyeing waste liquid can be recovered in a reusable state. Also, the dyeing waste liquid can be effectively filtered without using chemicals. Therefore, it is possible to reduce the processing cost associated with the addition of chemicals, and to provide the filtration processing means 11 taking into consideration the natural environment.

  The removal step 20 is a step for decolorizing the filtrate sent from the recovery step 10 and removing HBCD dissolved in the filtrate, and includes an aggregation treatment unit 21 and an adsorption treatment unit 22.

The agglomeration processing means 21 is a processing means for decolorizing the filtrate sent from the recovery step 10 and agglomerating and coarsening fine particles contained in the filtrate.
A flocculant is added to the filtrate sent from the recovery step 10 in a coagulation sedimentation tank provided in the coagulation treatment means 21. Thereby, the fine particles contained in the filtrate are aggregated and coarsened, and the filtrate is decolorized. Thereafter, the aggregated and coarsened fine particles are collected as sludge, and the decolored supernatant liquid is sent to the adsorption processing means 22.
By providing the aggregation treatment means 21 in this way, the filtrate can be reliably decolored and the fine particles contained in the filtrate can be effectively recovered.

Further, by providing the membrane filtration processing means 11 as a pre-process of the coagulation processing means 21 and collecting particulate HBCD, the amount of coagulant added and the amount of discharged coagulated sediment in the post-aggregation processing means 21 can be reduced. Can be reduced. Therefore, the processing load on the aggregation processing means 21 can be greatly reduced, and the processing cost can be significantly reduced.
Any flocculant may be used as long as it is normally used as a flocculant.
The amount of the flocculant added is desirably 0.01% to 1.0% with respect to the mass of the filtrate.

The adsorption processing means 22 is a processing means for adsorbing and removing HBCD dissolved in the supernatant liquid sent from the aggregation processing means 21.
The supernatant liquid sent from the coagulation treatment means 21 is sent to an activated carbon adsorption tower provided in the adsorption treatment means 22, and HBCD dissolved in the supernatant liquid is adsorbed on the activated carbon.
As the activated carbon, as long as it is usually used for waste water treatment and decolorization treatment, the material may be any of wood, insulator, coal, etc., and the shape thereof is any powder, granular, etc. Although there may be, it is desirable to use macropore activated carbon. By using macropore activated carbon, HBCD dissolved in the supernatant can be effectively adsorbed and removed.
The supernatant liquid sent to the adsorption treatment means 22 is discharged as treated water after adsorption treatment with activated carbon.

Example 1
The dyeing waste liquid containing particulate HBCD as a flame retardant (in the table, it is referred to as raw water) was filtered using an MF membrane module having a pore size of 0.1 μm. Filtration was performed by a cross flow method, and the liquid properties of MF membrane treated water, backwash water tank, and raw water tank were measured. Table 1 shows the results of the liquid volume, HBCD, suspended solids (SS in the table), and chemical oxygen demand (COD in the table).

  According to Table 1, it turns out that HBCD discharged | emitted by the backwash water tank is high concentration.

(Example 2)
A certain amount of coagulating precipitant was added to the MF membrane treated water filtered through the MF membrane module, and the turbidity after 20 minutes was measured. The agglomeration treatment conditions are as follows.
Dyeing drainage: 100 mL
Aggregating and precipitating agent: Liquid A-Silchia F (manufactured by Nikka Chemical Industries)
B liquid-Silkia AN (manufactured by Nikka Chemical Industries)
The measurement results are shown in Table 2.

According to Table 2, it can be seen that the dyed wastewater can be decolored by passing through the MF membrane module even if the consumption of the coagulating precipitant is reduced.
In addition, the HBCD concentration of the supernatant after the aggregation treatment was 0.005 mg / L or less.

(Example 3)
Assuming the HBCD concentration in the supernatant after the flocculation treatment, an adsorption equilibrium test with macropore activated carbon was performed. The results are shown in Table 3. Moreover, the adsorption isotherm of the dissolved HBCD by macropore activated carbon is shown in FIG.

  According to Table 3 and FIG. 2, it can be seen that the remaining HBCD dissolved in the supernatant can be adsorbed and removed by activated carbon (AC).

It is explanatory drawing which shows the system of the collection | recovery / removal method of the brominated flame retardant which concerns on embodiment of this invention. It is a figure which shows the adsorption | suction isotherm of dissolved HBCD by the macropore activated carbon in Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recovery / removal system of brominated flame retardant 10 Recovery process 11 Membrane filtration processing means 20 Removal process 21 Aggregation processing means 22 Adsorption processing means

Claims (2)

  A method for recovering and removing brominated flame retardant contained in a dyeing waste liquid from the dyeing waste liquid, a recovery step for recovering the brominated flame retardant from the dyeing waste liquid for reuse, and a bromination flame retardant from the dyeing waste liquid. A removal step for removal for disposal, and the recovery step has a membrane filtration treatment means for filtering the dyed waste liquid using a filtration membrane, and the removal step is a filtration filtered by the membrane filtration treatment means. A coagulation treatment means for agglomerating and coarsening fine particles contained in the liquid; and an adsorption treatment means for adsorbing the brominated flame retardant dissolved in the supernatant liquid after the aggregation treatment generated by the aggregation treatment means to the adsorbent. A method for recovering and removing brominated flame retardants.   The method for recovering and removing a brominated flame retardant according to claim 1, wherein the filtration membrane in the membrane filtration means comprises a pore diameter of 0.1 to 1.0 µm.

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