JP2017006841A - Method for reusing trehalose-containing wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating trehalose-containing wastewater after a preservation treatment of wood products by trehalose impregnation method, and reusing same.SOLUTION: In the method: a warming unit is attached to a raw water tank 1 and the temperature of a trehalose-containing wastewater is adjusted to be in a range of 30 to 50°C; a pump 30 is driven to send the trehalose-containing wastewater from a water-sending line 11 to an ultra-filtration membrane (UF membrane) module 2 for membrane separation treatment to separate into a trehalose-containing permeated liquid and a lignin-containing concentrated liquid, followed by reusing the trehalose-containing permeated liquid as a preservation treatment liquid for wood products by a trehalose impregnation method.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for treating and reusing wastewater containing trehalose after preserving wooden products such as wooden artifacts.

Wooden artifacts excavated from the ruins and wooden relics such as wood are preserved by applying a trehalose impregnation method in which a trehalose aqueous solution is impregnated to prevent shrinkage and deformation.
The trehalose aqueous solution used for the preservation treatment contains lignin and the like derived from wooden artifacts and is difficult to use repeatedly. At present, the trehalose aqueous solution after the preservation treatment is drained.

  Patent Document 1 describes an invention including a step of separating lignin and a decomposition product thereof by hydrolyzing cellulosic biomass to obtain a saccharified solution and then treating the permeate with an ultrafiltration membrane. However, there is no known method for treating and reusing wastewater containing trehalose.

JP 2014-128213 A

  An object of the present invention is to provide a method for treating wastewater containing trehalose after preserving a wooden product such as a wooden relic by the trehalose impregnation method and reusing it as a preservation solution for wooden products by the trehalose impregnation method. .

The present invention is a method of treating a wastewater containing trehalose after preserving a wooden product by a trehalose impregnation method, and reusing it as a preservation solution for a wooden product by a trehalose impregnation method,
After treating the wastewater containing trehalose with an ultrafiltration membrane module and separating it into a permeate containing trehalose and a concentrate containing lignin,
Provided is a method for reusing a permeate containing trehalose as a preservation solution for wood products by trehalose impregnation.

  By applying the present invention, the treated trehalose aqueous solution can be reused as a preservation treatment solution for wooden products such as wooden relics.

The figure which showed the processing flow for enforcing the method of this invention.

This will be described with reference to FIG.
In the raw water tank 1, a trehalose aqueous solution (drainage containing trehalose) after preserving the wooden relics by applying the trehalose impregnation method is sent from the raw water line 10 and stored therein.
The wastewater containing trehalose, which is the raw water, contains trehalose and lignin that oozes onto the surface of the wooden artifacts.

A heating device is attached to the raw water tank 1 to heat the waste water containing trehalose as raw water.
The heating at this time is preferably such that the temperature of the wastewater containing trehalose is in the range of 30 to 50 ° C.

The wastewater containing trehalose in the raw water tank 1 is driven by the pump 30 and sent from the water supply line 11 to the ultrafiltration membrane (UF membrane) module 2 for membrane separation.
A known UF membrane module can be used.
The UF membrane is preferably a hollow fiber membrane made of polyacrylonitrile, polyethersulfone or the like.
The molecular weight cutoff of the UF membrane is not particularly limited as long as it can separate trehalose and lignin, but is preferably 10,000 or more, more preferably 10,000 to 30,000.

  In the processing flow shown in FIG. 1, there is only one UF membrane module, but since there is a range in the molecular weight of the lignin to be separated, two UF membranes having different molecular weights as necessary are provided. The above UF membrane modules can be combined.

The permeate separated by the UF membrane module 2 is sent from the permeate line 12 to the permeate tank 3 and stored therein.
The permeate (trehalose aqueous solution) in the permeate tank 3 is a method for preserving wooden relics after being taken out from the line 13, as it is, or after being diluted or added with trehalose. It can be used as a storage solution by trehalose impregnation method.

All or part of the concentrate separated by the UF membrane module 2 can be returned to the raw water tank 1 from the concentrate return line 14 and processed again.
A part of the concentrate separated by the UF membrane module 2 can be drained from the concentrate drain line 15.

The filtration operation in the UF membrane module 2 is preferably stopped and washed appropriately.
For the cleaning, a known cleaning method such as back pressure cleaning, immersion cleaning, or flash cleaning can be applied.
When performing the reverse pressure cleaning, the pump 31 is driven, and the cleaning water (tap water or groundwater) in the counter pressure cleaning water tank 4 is passed through the back pressure cleaning water line 16 and the permeate line 12 to the permeate of the UF membrane module 2. Send it to the exit. A chemical such as an alkali can be added to the reverse pressure washing water as necessary.
The washing waste water is drained from the drain line 17.
These filtration operation and washing operation are performed by appropriately opening and closing the open / close valves (electromagnetic valves and the like) 20 to 24, respectively.

The method of reusing as a preservation solution for wooden products by the trehalose impregnation method of the present invention can be carried out by being incorporated in a treatment procedure in a preservation treatment method using a trehalose impregnation method such as a wooden relic. One embodiment will be described.
(Procedure 1)
After protecting the wooden relics with a nonwoven fabric or a net, it is immersed in an impregnation tank (with a heating device) filled with a trehalose aqueous solution (for example, a trehalose 30% by mass aqueous solution).
(Procedure 2)
Next, the trehalose aqueous solution in the impregnation tank is gradually heated to 40 to 80 ° C.
In this process, the trehalose concentration is finally increased to about 70% by mass by evaporation of water and addition of trehalose.
(Procedure 3)
Then, the wooden relics are pulled up from the impregnation tank and quenched to clean the surface and then dried.
(Procedure 4)
A permeate containing trehalose is obtained by applying the method of the present invention using the trehalose aqueous solution after the storage treatment as raw water.
(Procedure 5)
After adjusting the trehalose concentration in the permeate containing trehalose, step 1 to step 4 are performed.
By repeating such procedures 1 to 5, the method of the present invention can be implemented as a method for preserving wooden products such as wooden artifacts.

  By carrying out the method of the present invention, it becomes possible to repeatedly use the preserving treatment solution (trehalose aqueous solution) that has been drained conventionally, so that the preservation treatment cost can be reduced and the cultural value is very high. Wooden relics can be treated with a fresh preservation solution (trehalose aqueous solution), and wooden relics with relatively low cultural value can be used properly, such as using the treated trehalose aqueous solution as a preservation treatment solution. .

<Turbidity>
Absorbance at 720 nm was measured with a spectrophotometer (using a cell with a layer length of 10 mm) to obtain turbidity.

<Coloring degree>
Absorbances at 420 nm and 720 nm were measured with a spectrophotometer (using a cell with a layer length of 10 mm), and the difference between them was defined as the degree of coloring.

<Concentration ratio>
It calculated from the coloring degree of raw | natural water and a concentrate.

Example 1
The trehalose aqueous solution after treating the wooden relics by the trehalose impregnation method was treated by the treatment flow shown in FIG.
The liquid temperature in the raw water tank 1 was maintained at about 40 ° C.

Raw water (drainage containing trehalose) was filtered through the UF membrane module 2.
As the UF membrane module, an FB03 module (membrane area 0.013 m ² ) equipped with a polyacrylonitrile hollow fiber membrane (FUY03A1, fractional molecular weight 30,000, manufactured by Daisen Membrane Systems Co., Ltd.) was used.
The average filtration flow rate during a filtration operation for 535 minutes at a raw water inlet pressure of 50 kPa was about 15 L / m ² · hr. The concentrate was circulated.
Table 1 shows the turbidity, coloring degree, and concentration ratio of the permeate.
The filtration performance (pure water permeability coefficient) after the filtration operation was about 50% with respect to the filtration performance at the beginning of the operation, but when the back pressure washing with the sodium hydroxide aqueous solution (pH 12) was performed, the operation was performed. The previous filtration performance was restored.

Example 2
The trehalose aqueous solution after treating the wooden relics by the trehalose impregnation method was treated by the treatment flow shown in FIG.
The liquid temperature in the raw water tank 1 was maintained at about 40 ° C.

Raw water (trehalose drainage) was filtered through the UF membrane module 2.
As the UF membrane module, an FB03 module (membrane area 0.013 m ² ) equipped with a polyacrylonitrile hollow fiber membrane (FUY03A1, fractional molecular weight 30,000, manufactured by Daisen Membrane Systems Co., Ltd.) was used.
The average filtration flow rate during a filtration operation for 1096 minutes at a raw water inlet pressure of 80 kPa was about 15 L / m ² · hr. The concentrate was circulated.
Table 1 shows the turbidity, coloring degree, and concentration ratio of the permeate.
The filtration performance (pure water permeability coefficient) after completion of the filtration operation was about 20% of the filtration performance at the initial stage of the operation. However, when back pressure washing with a sodium hydroxide aqueous solution (pH 12) was performed, the operation was performed. It recovered to about 95% of the previous filtration performance.

Example 3
The trehalose aqueous solution after treating the wooden relics by the trehalose impregnation method was treated by the treatment flow shown in FIG.
The liquid temperature in the raw water tank 1 was maintained at about 40 ° C.

Raw water (trehalose drainage) was filtered through the UF membrane module 2.
As the UF membrane module, an FB03 module (membrane area 0.013 m ² ) equipped with a polyethersulfone hollow fiber membrane (FUS0181, fractional molecular weight 10,000, manufactured by Daisen Membrane Systems Co., Ltd.) was used.
The average filtration flow rate during the 180 minute filtration operation was about 10 L / m ² · hr or less at a raw water inlet pressure of 55 kPa. The concentrate was circulated.
Table 1 shows the turbidity, coloring degree, and concentration ratio of the permeate.
In addition, the filtration performance (pure water permeability coefficient) after completion of the filtration operation was about 10% with respect to the filtration performance at the initial stage of the operation. When back pressure washing with an aqueous sodium hydroxide solution (pH 12) was performed, the filtration performance recovered to about 35% before the operation.

  As is clear from the comparison of the turbidity and coloring degree of the raw water, concentrated liquid, and permeate shown in Table 1, the permeate is impregnated with trehalose by treating the trehalose aqueous solution after the preservation treatment of the wooden relics by applying the present invention. It can be reused as a preservation treatment solution by the method.

  INDUSTRIAL APPLICABILITY The present invention can be repeatedly used for preserving wooden relics by treating a trehalose aqueous solution used in a trehalose impregnation method, which is a method for preserving wooden relics excavated from remains and the like.

1 Raw Water Tank 2 UF Membrane Module 3 Permeate Tank 4 Backwash Water Tank

Claims (5)

A method of treating wastewater containing trehalose after preserving and treating wood products by trehalose impregnation method, and reusing it as a preservation solution for wooden products by trehalose impregnation method,
After treating the wastewater containing trehalose with an ultrafiltration membrane module and separating it into a permeate containing trehalose and a concentrate containing lignin,
A method of reusing a permeate containing trehalose as a preservation solution for wood products by trehalose impregnation.   The recycling method according to claim 1, wherein the wastewater containing trehalose is heated so as to be in a temperature range of 30-50 ° C.   The recycling method according to claim 1 or 2, wherein the concentrated solution is returned to the waste water containing trehalose and circulated.   The recycling method according to any one of claims 1 to 3, wherein the ultrafiltration membrane used in the ultrafiltration membrane module is a hollow fiber membrane made of polyacrylonitrile.   The recycling method according to claim 1, wherein the wooden product is a wooden relic.

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