JPH067769A - Method and apparatus for treating photographic waste solution - Google Patents

Abstract

PURPOSE:To certainly treat a waste solution by evaporating and concentrating the waste solution and bringing evaporated vapor into contact with sodium hydroxide to make the org. acid in the vapor absorbed and burning the formed solution containing the sodium salt of the org. acid and the formed conc. solution. CONSTITUTION:A photographic waste solution 1 is supplied to evaporative concn. equipment 3 through a storage tank 2 to be evaporated and conc. by a heater 3B and an evaporation boiler 3A. The generated vapor is guided to an org. acid absorption column 5 to be brought into contact with sodium hydroxide and the org. acid in the vapor is neutralized and absorbed. This solution of the sodium salt of the org. acid is passed through the evaporation boiler 3A to enter a concn. tank 16. The vapor after the absorption operation is cooled and condensed by a condenser 8 and the condensate is supplied to a temporary storage tank 9 or passed through an ammonia absorption column 15 to neutralize ammonia and the obtained conc. solution is sent to a concn. solution tank 16 and guided to liquid combustion equipment 11 to be burnt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating photographic waste liquid.

[0002]

2. Description of the Related Art A photographic waste liquid contains a developing solution and a fixing solution. For example, the developer contains ten or more kinds of organic substances such as acetic acid and organic acids such as phenol, alkali such as ammonia and the like.

At present, only the ocean dumping route is selected.

[0004]

However, ocean dumping naturally causes pollution of the sea, and other treatment methods are desired.

However, since the photographic waste liquid contains a wide variety of organic substances that are different in nature, it cannot be subjected to biological treatment or physicochemical treatment, and cannot be separated from water by distillation. .

Although it is possible to adsorb organic acids, ammonia and the like with activated carbon, the amount of activated carbon required is enormous due to the large amount of treatment waste liquid, which makes practical application extremely difficult.

Further, it is possible to reduce the amount by evaporating and concentrating, but the evaporative vapor contains an organic acid and an alkali, has a strong odor, and the concentrated residue is in the form of paste and contains toxic substances. So this cannot be finalized.

[0008] Therefore, an object of the present invention is to surely process photographic waste liquid.

[0009]

According to the method of the present invention, which has solved the above-mentioned problems, a photographic waste liquid is evaporated and concentrated, and the evaporative vapor is brought into contact with sodium hydroxide to absorb an organic acid in the photographic waste liquid to obtain a sodium organic acid solution. The organic acid sodium salt solution and the concentrated liquid resulting from the evaporative concentration are liquid-combusted.

At this time, the evaporative vapor is brought into contact with sodium hydroxide to absorb the organic acid in the photographic waste liquid,
The solution can be brought into contact with sulfuric acid to absorb the ammonia content to form an organic acid sodium salt solution and an ammonium sulfate solution.
In addition, after condensing the evaporation vapor after the organic acid absorption operation, after adjusting the pH of the condensate with sulfuric acid, it is transferred to a sewage treatment system, or with the condensate that is condensed evaporation vapor after the organic acid absorption operation. After that, the pH of the ammonium sulfate solution obtained by bringing the evaporative vapor into contact with sulfuric acid is adjusted with sulfuric acid and then transferred to the sewage treatment system. Depending on the conditions around the area where the treatment facility is installed, at least the condensate of the condensate obtained by condensing the vaporized vapor after the organic acid absorption operation and the ammonium sulfate solution obtained by subsequently contacting the vaporized vapor with sulfuric acid. The ammonia component is separated by a stripper, the ammonia component is supplied to liquid combustion, and the separated liquid is adjusted to pH with sulfuric acid.
After adjustment, it can be transferred to a sewage treatment system.

On the other hand, the apparatus of the present invention comprises a photographic waste liquid evaporative concentration facility, an organic acid absorption tower using sodium hydroxide of the evaporative vapor, and a vapor condenser cooling condenser containing ammonia after absorbing the organic acid. , A stripper for separating the ammonia content in the condensate, a pH adjusting tank for adjusting the pH of the separated ammonia content with sulfuric acid, and a concentrated liquid from the evaporative concentration equipment and the ammonia content separated by the stripper. And a means for discharging pH-adjusted effluent.

[0012]

In the present invention, the photographic waste liquid is evaporated and concentrated, and the evaporated vapor is brought into contact with sodium hydroxide to absorb the organic acid in the photographic waste liquid to form a sodium organic acid solution. This organic acid sodium salt solution can be incinerated by liquid burning.

On the other hand, since the evaporation vapor after being brought into contact with sodium hydroxide contains ammonia, the condensate obtained by cooling and condensing it or the vapor after being brought into contact with sodium hydroxide is evaporated. By adjusting the pH with sulfuric acid together with the ammonium sulfate solution obtained by contacting the vapor with sulfuric acid, it can be sent to the sewage treatment system.

Further, the condensate alone or together with the ammonium sulfate solution is sent to an ammonia stripper to separate the ammonia content, and the ammonia content is subjected to liquid combustion, and the liquid from which the ammonia has been separated is converted to sulfuric acid.
If the pH is adjusted, it can be sent to the sewage treatment system.

Thus, since the liquid combustion system and the sewage treatment system are separately treated, the operating cost of the liquid combustion is reduced,
Overall processing costs are reduced.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the examples shown in the flow sheet of FIG. Photographic effluent 1, for example a mixture of a developing solution and a fixing solution, is supplied to an evaporative concentrating facility 3 via a photographic effluent storage tank 2. As the evaporative concentration equipment 3, any appropriate equipment can be used. The embodiment is a forced circulation type evaporative concentration equipment having a heater 3B heated by a heating source 4 and an evaporator 3A.
An organic acid absorption tower 5 is provided and sodium hydroxide 6 is added.

The organic acid in the evaporation vapor from the evaporator 3A is absorbed by sodium hydroxide to form an organic acid sodium solution. The organic acid sodium salt solution is transferred into the evaporator 3A and finally introduced into a concentrated liquid tank 16 described later. The vapor after the absorption operation is guided to the condenser 8 through the pipe 7 and cooled and condensed. The condensate in the condenser 8 passes through the temporary storage tank 9 and the stripper 10
Is supplied to. In this stripper 10, the ammonia component in the condensate is separated, and the ammonia vapor is put into the liquid (waste liquid) combustion facility 11.

The liquid from which the ammonia component has been separated in the stripper 10 is supplied to the pH adjusting tank 12. In this pH adjusting tank 12, sulfuric acid 13 is added, preferably
Heading to the sewage treatment plant as discharged water 14 in the state of pH 6 to 8.

On the other hand, the vapor that has passed through the organic acid absorption tower 5 still contains a large amount of ammonia, which is disadvantageous in terms of odor. Therefore, the ammonia absorption tower 15 is provided by branching from the above-mentioned pipe line 7, to which sulfuric acid is added to absorb ammonia. The ammonia absorbing liquid is introduced from the bottom of the tower together with the concentrated liquid of the evaporator 3A through the concentrated liquid tank 16 and the above-mentioned ammonia vapor through the spray nozzle of the liquid combustion equipment 11. A part of the ammonia absorption liquid may be supplied to the stripper 10 via the temporary storage tank 9 together with the condensed liquid in the condenser 8 instead of being guided to the concentrated liquid tank 16.

In the liquid combustion equipment 11, the auxiliary fuel 17 is injected from the burner at the upper part to mainly burn the organic acid sodium liquid. A dissolver 18 is provided in the lower part of the liquid combustion equipment 11, and is a sodium sulfate solution. The combustion exhaust gas is desulfurized by an exhaust gas treatment facility, for example, a venturi scrubber 19, passes through a white smoke prevention heater 20, and is then emitted from a chimney 21.

If necessary, the sodium sulfate solution from the dissolver 18 can be supplied to the pH treatment tank 12. In addition, it is desirable that the pH-adjusted liquid is once air-oxidized and then discharged as sewage.

If there is a sewage treatment plant in the area where the apparatus of the present invention is installed, the ammonia absorption tower 15 can be omitted if necessary, but if not, as shown in the figure, the ammonia absorption tower 15 can be omitted. It is desirable to install the absorption tower 15 and use the concentrated ammonia sulfate solution for liquid combustion. It is not essential to install the stripper 10, and the condensate can be directly introduced into the pH adjusting tank 12.

(Experimental example) The usefulness of the present invention will be explained by showing an experimental example which is the basis of the present invention. Evaporating 500 ml of each liquid shown in Table 1 and evaporating and concentrating 400 ml four times with 100 ml each, pH, COD, and reducibility of 5 kinds of liquid in each step liquid and residual liquid 100 ml, respectively. The amounts of total S, free ammonia, phenol and acetic acid were measured, and the appearance and odor were also measured. The results are shown in Tables 1 and 2. The two-stage absorption liquid is obtained by performing distillation by providing a flask 52 containing 50 ml of 4 wt% NaOH in series with a 500 ml flask 51 as shown in FIG.

[0024]

[Table 1]

[0025]

[Table 2]

From this result, the developing solution: fixing solution (1: 1)
The mixed solution itself contained a large amount of free ammonia, phenol and acetic acid, whereas when the pH was adjusted to 10, the amount of phenol and acetic acid became 40 ppm or less. However, a large amount of NaOH is required to reach pH 10,
As shown in the neutralization curve in FIG. 3, it was also found that about 30 g of 100% NaOH was required for 1 liter of the mixed solution. Although the distillation property of phenol is not so good, the amount of acetic acid contained is the main problem, and it was confirmed that the treatment method of the present invention can achieve the object.

[0027]

As described above, according to the present invention, the photographic waste liquid can be surely processed with a small energy consumption close to self-combustion.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example for carrying out the method of the present invention.

FIG. 2 is a schematic diagram showing experimental equipment.

FIG. 3 is a neutralization curve diagram.

[Explanation of symbols]

1 ... Photo waste liquid, 3 ... Evaporative concentration equipment, 5 ... Organic acid absorption tower,
8 ... Condenser, 10 ... Stripper, 11 ... Liquid combustion equipment, 12 ... pH adjusting tank, 15 ... Ammonia absorption tower.

 ─────────────────────────────────────────────────── (72) Inventor Ryuji Takeda 2-17-15 Tsukushima, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. (72) Yoshinobu Sato 2-17-15 Tsukushima, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. (72) Inventor Hidetoshi Suyama 2-17-15 Tsukushima, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. (72) Inventor Yasuhiko Miyoshi 2-23-2 Kitamachi, Jindaiji, Chofu, Tokyo 207

Claims (6)

[Claims] 1. A photographic waste liquid is concentrated by evaporation, and the evaporation vapor is brought into contact with sodium hydroxide to absorb an organic acid in the photographic waste liquid to form an organic acid sodium solution, and this organic acid sodium solution and the concentration accompanying the evaporation concentration are carried out. A method for treating photographic waste liquid, characterized in that the liquid burns. 2. The evaporative vapor is brought into contact with sodium hydroxide to absorb the organic acid in the photographic waste liquid, and then brought into contact with sulfuric acid to absorb the ammonia component, thereby forming a sodium organic acid solution and an ammonium sulfate solution. A method for treating the photographic waste liquid described. 3. The method for treating photographic waste liquid according to claim 1, wherein the evaporated vapor after the organic acid absorption operation is condensed, the condensate is subjected to pH adjustment treatment with sulfuric acid, and then transferred to a sewage treatment system. 4. A condensate obtained by condensing an evaporative vapor after an organic acid absorption operation, and an ammonium sulfate solution obtained by subsequently contacting the evaporative vapor with sulfuric acid are subjected to pH adjustment treatment with sulfuric acid, and then added to a sewage treatment system. Claim 1 or 2 to transfer
A method for treating the photographic waste liquid described. 5. Among the condensate obtained by condensing the evaporation vapor after the organic acid absorption operation and the ammonium sulfate solution obtained by bringing the evaporation vapor into contact with sulfuric acid thereafter, at least the condensate is stripped with an ammonia content. Separate
The ammonia content is supplied to liquid combustion, and the separated liquid is adjusted to pH with sulfuric acid and then transferred to a sewage treatment system.
A method for treating the photographic waste liquid described. 6. A photographic waste liquid evaporative concentration facility, an organic acid absorption tower using sodium hydroxide of the evaporative vapor, a vapor condenser cooling condenser containing ammonia after absorbing the organic acid, and a condensate of the condensed liquid. A stripper that separates the ammonia content, a pH adjusting tank that adjusts the pH of the liquid from which the ammonia content has been separated with sulfuric acid, and a liquid combustion that liquid-burns the concentrated liquid from the evaporative concentration equipment and the ammonia content that is separated by the stripper. A photographic wastewater treatment apparatus comprising: equipment, exhaust gas treatment equipment for exhaust gas from a liquid combustion equipment, and means for discharging pH-adjusted wastewater.