JPH06277654A - Vacuum evaporation treatment of photographic waste solution - Google Patents

Abstract

PURPOSE:To efficiently and inexpensively remove ammonia from ammonia- containing gas formed when ammonia is removed from a condensed soln. generated by the vacuum evaporative concn. of a photographic waste soln. by a simple means. CONSTITUTION:The steam generated when a photographic waste soln. is subjected to vacuum evaporative concn. is condensed to be separated into a conc. waste soln. and a dilute condensed soln. and the condensed soln. is brought into contact with air to remove ammonia in the condensed soln. and the ammonia-containing gas obtained at this time is guided to a catalyst packed bed to be brought into contact with a catalyst to decompose and remove ammonia. The temp. of the catalyst is pref. set to 500 deg.C or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a photographic waste liquid, and more particularly, to removing harmless ammonia in a condensate generated by a distillation operation of a photographic waste liquid to render it harmless, thereby performing a vacuum evaporation treatment of the photographic waste liquid. The present invention relates to a method for treating photographic waste liquid that can prevent the environment of gases released into the atmosphere from being affected.

[0002]

2. Description of the Related Art Photographic processing of silver halide photographic light-sensitive materials, for example, in the case of color light-sensitive materials, steps such as color development, bleach-fixing (or bleaching, fixing), washing with water, stabilization are used. In order to replenish the components consumed by the treatment, the replenishing liquid is supplied and the excess liquid is discharged, so various waste liquids are discharged from each process. These photographic waste liquids contain various components depending on the composition of the processing liquid in each process. Therefore, the photographic waste liquid contains nitrogen, phosphorus, COD components, BOD components, sulfate ions, etc. For example, in the case of a developing waste liquid, the pH is high, and in addition, a large amount of oxidizing and reducing substances is contained depending on the liquid. . The nitrogen content in the photographic waste liquid causes eutrophication of water bodies when the liquid is discharged, and therefore it is desirable to remove it regardless of the regulation. Ammonia in photographic effluent is the main nitrogen source in the liquor.

For this reason, each photographic processing company has a specialized waste liquid processing company collect the waste liquid at a processing cost and installs a detoxification processing facility. However, the method entrusted to a waste liquid treatment company requires a considerable space to store the waste liquid, and the amount of the waste liquid entrusted is determined by the volume, which makes the cost extremely expensive. . Further, the detoxification treatment facility has a problem that the initial investment (initial cost) is large. Therefore, it is economical that the amount of the waste liquid is small even if the waste liquid is delivered to a waste liquid recovery company or is treated in-house. Further, when treating the waste liquid collected by a waste liquid collecting company, it is often economical to reduce the volume of the waste liquid prior to the treatment. In addition, it is often advantageous for collectors to reduce the amount of waste liquid even when the concentrated liquid is further transported for final disposal.

As described above, since it is often advantageous to reduce the volume in each stage of the waste liquid treatment, it has been proposed for a long time to perform evaporative concentration. However, when evaporating and concentrating, the temperature is raised to almost 100 ° C. and the liquid is boiled at normal pressure to condense the volatile components contained in the waste liquid or the volatile components generated from substances that are easily decomposed by heating in the waste liquid. Is released into the atmosphere. As an advantageous method that has less impact on the environment than evaporative concentration, there is also a distillation method, that is, a method in which vaporized components are not released to the atmosphere and cooled to condense so that treatment is unnecessary or a dilute liquid that is easy to treat is recovered. Are known. Even in such a distillation method, the atmospheric pressure distillation method in which the waste liquid is raised to about 100 ° C. and the liquid is boiled is also used, and in the airtight system of the waste liquid, the atmospheric pressure of the system is lowered by a vacuum pump or an ejector to lower the temperature, for example. There is a reduced pressure evaporation method which can be operated by evaporating a waste liquid at an evaporation temperature close to room temperature.

Among the distillation methods, when the apparatus or liquid is heated to a high temperature as in the case of the atmospheric distillation method, there arises a problem in the material usable for the apparatus, and in the generated steam, and thus in the condensed liquid, relatively. There is also the drawback of introducing hot runoff volatile contaminants. Therefore, the vacuum distillation method is most desirable. However, since various volatile substances are contained in the photographic waste liquid, these substances enter the distillate obtained by the vacuum distillation method and cannot be discharged. For example, since the color developer for silver chlorobromide color paper contains benzyl alcohol, the waste liquid also contains the alcohol,
Since the alcohol has a relatively high vapor pressure, it enters a large amount in the distillate and sometimes reaches a BOD of 5,000 ppm. The black and white developer contains ethylene glycol, diethylene glycol, and amines having relatively low boiling points, and brings about the same increase in BOD as described above.

Many fixing solutions contain ammonium thiosulfate, and in the waste solution mixed with the developing solution, the pH rises, so that ammonia is mixed in the distillate solution. When the pH rises in this way, the problem of containing ammonia occurs. Further, sulfur dioxide and sulfidizing gas are mixed into the distillate from the waste liquid of the fixer and the bleach-fixer to lower the pH. As described above, when the photographic waste liquid is distilled, the water quality control factor substance having a low boiling point enters the distillate liquid depending on the type of the waste liquid, but the way in which the substance enters changes depending on the distillation conditions such as temperature and pressure. For example, when the color negative / paper mixed waste liquid is distilled, ammonia is volatilized and the pH of the distillate is 9, and the ammonia concentration is 2,000.
Although the concentration becomes 0 ppm, when the distillation is continued and the concentrated liquid becomes a solid residue, the distillate finally contains sulfur-based gas such as sulfurous acid gas up to 5,000 mg / liter or more. For details, see American Academy of Photography (SPSE).
Iwano et al.'S report of the 6th International Symposium on Photofinishing Technology (February 1990, Las Vegas). Thus, it is necessary to remove ammonia in the distillate in the distillation method.

[0007] On the other hand, various means have already been proposed to prevent ammonia in gas or liquid from being released into the atmosphere or water. There are various methods for these means, and the typical ones are as follows. (1) Biological decomposition The ammonia content in water is denitrified by biological decomposition such as activated sludge treatment. This method is suitable for large scale treatment of municipal sewage. (2) Incineration When ammonia in a gas is heated in the presence of oxygen, it is converted into nitric oxide, nitrogen, etc. by oxidation or decomposition. Such heat treatment occurs during combustion of harmful gas and thermal decomposition. Since nitric oxide is harmful, it is removed in the denitration process. If ammonia is to be removed only by thermal decomposition without a denitration step, 800-1
At a high temperature of 000 ° C, nitrogen oxide and ammonia are changed to nitrogen to render it harmless. In this case, there are large scale incinerators operating at high temperatures. (3) Reuse Ammonia can be collected and reused if it is large in scale, rather than being decomposed by biological decomposition or incineration. However, in the case of photographic waste liquid, especially developing waste liquid, it is not economical to take a means of collecting and reusing it in terms of scale.

[0008]

In the treatment of photographic waste liquid containing a large amount of ammonia component, the amount of the liquid is relatively small, and therefore the above-mentioned conventional technique cannot be applied. Therefore, it is necessary to develop a method capable of efficiently removing ammoniacal nitrogen on a smaller scale than these conventional techniques. As described above, when ammonia is removed from the condensate obtained by evaporating the photographic waste liquid under reduced pressure, a gas containing ammonia is by-produced and it is meaningless to release this ammonia-containing gas into the atmosphere. Since it is not present, ammonia must be removed from the gas. If ammonia is removed from this ammonia-containing gas with an absorbing liquid,
Further, since waste liquid is generated, it is necessary to remove ammonia with high efficiency by such a simple means without generating such waste liquid. It is an object of the present invention to provide a method capable of efficiently treating ammonia mixed in a condensate obtained by evaporating and concentrating a photographic waste liquid under reduced pressure. Further, the present invention is a simple means for mixing ammonia mixed in the condensate obtained by evaporating and concentrating the photographic waste liquid under reduced pressure,
The object is to provide a method that can be processed at low cost.

[0009]

The present invention was able to achieve the above object by the following means. (1) Photographic waste liquid is evaporated and concentrated under reduced pressure, vapor generated at that time is condensed to separate the concentrated waste liquid and a dilute condensate, and the condensate is brought into contact with air to remove ammonia in the condensate, thereby containing the ammonia. A method for evaporating a photographic waste liquid under reduced pressure, which comprises decomposing ammonia by introducing a gas into a catalyst-packed bed to bring it into contact with a catalyst. (2) The method for decompressing photographic waste liquid under reduced pressure according to item (1), wherein the temperature of the catalyst in the catalyst packed bed is 500 ° C. or lower. (3) The method for vacuum evaporation treatment of photographic waste liquid according to the item (1), wherein the temperature of the catalyst in the catalyst packed bed is 150 to 400 ° C. (4) The catalyst in the catalyst packed bed is platinum, copper / chromium,
The method for vacuum evaporation of photographic waste liquid according to any one of (1) to (3) above, which is selected from iron series.

First, the step of contacting the condensate with air to remove ammonia in the condensate will be described. The air contacted with the condensate is 20 to 90 ° C., preferably 40 to 8
Use the one adjusted to 0 ° C. A countercurrent wetting wall column can be used effectively to remove the volatile components such as ammonia from the condensate by contacting air with the condensate distilled from the photographic waste liquid. The countercurrent wet wall tower is filled with a filler such as ceramic lashing ring. Examples of the filler include ceramic lash ring, glass lash rig, or granules of zeolite, kaolin, zeolite, and the like. The condensate is supplied as a downward flow from the top of the column, and the air is supplied as an upward flow into the column from an air supply pipe. The condensate flows down the surface of the packing material, forms a thin film there, and comes into contact with air rising from below, thereby forming a countercurrent wetting wall tower.

The amounts of the condensate and the air supplied into the countercurrent wetting wall column depend on the level to which volatile components such as ammonia in the coagulant are removed. The flow velocity ratio between the liquid phase (condensate) and the gas phase (air) is the weight ratio of the supplied condensate per time and the weight of air per time (L / L).
It is represented by G). This L / G value is in the range of 0.1 to 20,
The ratio is preferably 0.2 to 5, and the L / G value is preferably 0.8 or less in order to make the ammonia concentration in the treated water 100 mg / liter or less. Concentration of the condensate, that is, the ratio of the volume of the developing wastewater (stock solution) to the volume of the vacuum distillation distillate,
When the degree of concentration is high, the concentration of ammonia in the condensate is high, and other volatile components mixed in are increased, so that the effect of removing ammonia in the wetting wall column is reduced. In particular, acetic acid and sulfurous acid gas increase at the time of high concentration, which reduces efficiency. At low concentration, the original purpose of concentration will not be met.

As described above, acetic acid is an example of the substance that prevents the transfer of ammonia from the liquid phase to the gas phase.
When acetic acid is present in the condensate, that much ammonia is fixed in the condensate. In addition, if carbon dioxide gas is dissolved in the condensate, the transfer of ammonia to the gas phase is hindered. From such a viewpoint, the concentration ratio of the condensate is preferably about 3 to 12. In addition, it is also a preferable embodiment that the condensate is previously treated with activated carbon and then contacted with air. Activated carbon removes substances that interfere with the transfer of ammonia from the liquid phase to the gas phase, thus improving ammonia removal efficiency. In the same sense, a method of treating the condensate with zeolite in advance can improve the ammonia removal efficiency. A preferable example of the activated carbon is coconut shell activated carbon.

The ammonia-containing gas to be treated in the present invention is obtained by evaporating and condensing a photographic waste liquid under reduced pressure, condensing vapor generated at that time to separate it into a concentrated waste liquid and a condensate, and contacting the condensate with air. Any gas containing ammonia produced by removing ammonia in the condensate may be used. Although the original photographic waste liquid contained a large amount of many kinds of compounds in the condensate generated by evaporation under reduced pressure, it mainly contained ammonia, acetic acid, etc. The ammonia-containing gas produced by contacting air from the condensate mainly contains ammonia,
In addition, it contains only a small amount of a compound that interferes with the decomposition and removal of ammonia, and the ammonia-containing gas generated by the contact of the condensate with air can be treated satisfactorily.

For example, when the condensate obtained by evaporating the photographic waste liquid under reduced pressure has an ammonia concentration of about 2,000 ppm, the condensate is stripped (contacted with air) by air and the ammonia in the liquid is removed. The optimum operation condition for setting the concentration to 100 ppm or less at which the concentration can be discharged is set at a stripping operation temperature of 60 ° C. Under this operating condition, the ammonia concentration in the gas discharged by stripping is about 5,400 ppm, and the present invention sufficiently removes ammonia from such an ammonia-containing gas. In the present invention, such an ammonia-containing gas is introduced into the catalyst packed bed and brought into contact with the catalyst to decompose the ammonia. The temperature of the catalyst in the catalyst packed bed is set to 500 so that the decomposition of ammonia is sufficiently performed.
℃ or less, preferably 400 ℃ or less, more preferably 1
It is set to 50 to 400 ° C. The lower the temperature, the less the heat consumption, and the less the limitation of the device. The higher the temperature, the higher the degree of decomposition, but normally 800 to 1,00.
The thermal decomposition of ammonia at 0 ° C. can be carried out at a temperature of 500 ° C. or lower by using a catalyst.

As the catalyst used in the catalyst packed bed, platinum group metals such as platinum, copper / chromium, iron, titanium oxide, alumina, zeolite, iron oxide / alumina, nickel oxide and the like can be used, and in particular platinum and the like. Platinum group metals,
A copper-chromium or iron-based catalyst is preferable, and a platinum-based catalyst, and a catalyst in which platinum is supported on an alumina carrier are particularly preferable. Practically, an alumina carrier-platinum catalyst (manufactured by JGC Universal Co., Ltd.), a copper-chromium catalyst (manufactured by JGC Chemical Co., Ltd.), a titanium oxide catalyst (manufactured by Sakai Chemical Co., Ltd.), etc. can be used. Ammonia can be removed by passing an ammonia-containing gas obtained by bringing the above-mentioned condensate into air contact with this catalyst-packed bed. The treated gas from which the ammonia has been removed by passing through the above-mentioned catalyst packed bed can be released into the atmosphere as it is because the ammonia content is low, but the temperature is as described above. Since the temperature of the packed bed is kept high and the reaction is carried out and is high, it is advantageous to utilize the waste heat thereof for the evaporation of the photographic waste liquid and the ammonia stripping of the distillate before the discharge.

In order to carry out the process concretely, for example, the reduced pressure evaporative concentrator is operated at 40 ° C., the vapor generated there is condensed, the condensate is stored in the condensate tank, and the condensate is heated. To an ammonia stripping packed column operated at 60 ° C., and the ammonia-containing gas produced there
It is sent to a catalyst tank having a catalyst packed bed at a temperature of 0 ° C. to cause ammonia decomposition, and the exhaust gas (250 ° C.) converted into nitrogen is heat-exchanged to utilize waste heat and then in the atmosphere. To release. The heat exchange is carried out in order to supply heat to the vacuum evaporative concentrator and the ammonia stripping packed column. Since both devices have low temperatures, waste heat can be efficiently used. Further, heating is performed in order to keep the temperature of the catalyst packed bed in the above range, and the heating heat source therefor may be city gas, kerosene, or electric heat, but kerosene is relatively simple and inexpensive. . Electric heating has the advantage that it is extremely easy to control.

The method of the present invention can be applied to any photographic waste liquid, and can be applied to any photographic waste liquid in the processing of color photographs and black and white photographs. For example,
It can be applied to processing waste liquid in any processing such as development, bleaching, fixing, bleach-fixing, stabilizing bath, rinsing bath, pre-bath, neutralizing bath, conditioning bath, etc. It can also be applied to a waste liquid mixed with. Since the photographic waste liquid to be treated in the present invention is inevitably the main component of the photographic processing liquid because it is generated from the photographic processing liquid, the components contained in the photographic processing liquid will be described below. In addition, it contains reaction products such as oxidants of developing agents, sulfates, and halides generated in the photographic processing process, trace amounts of gelatin dissolved from the light-sensitive material, and components such as surfactants.

The photographic processing liquid includes color processing, black-and-white processing liquid, reducing solution for plate making work, development processing tank cleaning liquid, etc., depending on the processing object, and the photographic processing liquid depends on the processing contents, such as developing solution, fixing solution, There are types of bleaching solutions and image stabilizing solutions. Many color paper developers contain alkylene glycols and benzyl alcohols together with color developing agents, sulfites, hydroxylamine salts, carbonates, water softeners and the like. On the other hand, color negative developer,
Color positive developers and some color paper developers do not contain the above alcohols. Color developers usually contain an aromatic primary amine color developing agent. It is mainly a p-phenylenediamine derivative,
A typical example is N, N-diethyl-p-phenylenediamine,
2-Amino-5-diethylaminotoluene, 2-methyl-4- [N-ethyl-N- (β-hydroxyethyl) amino] aniline, N-ethyl-N- (β-methanesulfonamidoethyl) -3-methyl It is -4-aminoaniline. Further, these p-phenylenediamine derivatives are salts such as sulfates, hydrochlorides, sulfites and p-toluenesulfonates. The content of the aromatic primary amine developing agent is in the range of about 0.5 g to about 10 g per liter of developing solution.

The color developer contains various hydroxylamines as preservatives. Hydroxylamines may be substituted or non-substituted, and in the case of a substituted form, hydroxylamines in which the nitrogen atom is substituted with a lower alkyl group, particularly two alkyl groups (for example, having 1 to 3 carbon atoms) Hydroxylamines substituted by. The content of hydroxylamines is 0 to 5 g per liter of color developing solution. In the black and white developer, 1-phenyl-3-pyrazolidone, 1-
It includes phenyl-4-hydroxymethyl-4-methyl-3-pyrazolidone, N-methyl-p-aminophenol and its sulfates, hydroquinone and its sulfonates, and the like. Color and black-and-white developers usually contain sulfites such as sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium metasulfite, potassium metasulfite, and carbonyl sulfite adducts as preservatives. , The content of these is 0g-5
g / liter. As a preservative, a combination of N, N-dialkyl-substituted hydroxylamine and alkanolamine such as triethanolamine is also used in color and black and white developers.

The color and black and white developers have a pH of 9-12. Various buffers are used to maintain the above pH. As the buffer, carbonate, phosphate, borate, tetraborate, hydroxybenzoate, glycine salt,
N, N-dimethylglycine salt, leucine salt, norleucine salt, guanine salt, 3,4-dihydroxyphenylalanine salt, alanine salt, aminobutyrate, 2-amino-2-
Methyl-1,3-propanediol salt, valine salt, proline salt, trishydroxyaminomethane salt, lysine salt and the like can be used. Particularly, carbonate, phosphate, tetraborate, and hydroxybenzoate have excellent solubility and buffering ability in a high pH range of pH 9.0 or more, and even if added to a developer, adverse effects on photographic performance ( These buffers are often used because they have the advantages of not causing fog) and being inexpensive.
The amount of the buffer added to the developer is usually 0.1 mol / liter to 1 mol / liter.

In addition, the developing solution contains various chelating agents which are added as a precipitation inhibitor for calcium or magnesium or for improving the stability of the developing solution. Typical examples thereof are nitrilotriacetic acid, diethylenetriaminepentaacetic acid, nitrilo-N, N, N-trimethylenephosphonic acid,
Ethylenediamine-N, N, N ', N'-tetramethylenephosphonic acid, 1,3-diamino-2-propanoltetraacetic acid, transcyclohexanediaminetetraacetic acid, 1,3
-Diaminopropane tetraacetic acid, 2-phosphonobutane-1,
2,4-tricarboxylic acid, 1-hydroxyethylidene-
1,1-diphosphonic acid and the like. Two or more of these chelating agents may be used in combination as necessary.

The developing solution contains various development accelerators.
As the development accelerator, thioether compounds, p-phenylenediamine compounds, quaternary ammonium salts, p-
Aminophenols, amine compounds, polyalkylene oxides, 1-phenyl-3-pyrazolidones, hydrazines, mesoionic compounds, thione compounds, imidazoles and the like. Further, the developing solution often contains bromine ions for the purpose of preventing fog, but a developing solution containing no bromine ions may be used for a light-sensitive material mainly containing silver chloride. In addition, a compound that gives a chlorine ion such as NaCl or KCl may be contained as an inorganic antifoggant. If necessary, various organic antifoggants are contained. The organic antifoggant may contain, for example, adenines, benzimidazoles, benztriazoles and tetrazoles. The content of these antifoggants is 0.010 g / 2 g per liter of the developing solution. These antifoggants include those which are eluted from the light-sensitive material during processing and accumulated in the developing solution. Further, if necessary, various surfactants such as alkylphosphonic acid, arylphosphonic acid, aliphatic carboxylic acid, aromatic carboxylic acid are contained.

In photographic processing, a bleaching process is usually carried out after development, and the bleaching process may be carried out simultaneously with the fixing process by one-bath bleaching (Brix). The method of the present invention can be applied to such a processing waste liquid. The bleaching solution contains EDTA of iron (III) or Co (III) as an oxidizing agent, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, 1,3-diamino-propanetetraacetic acid, cyclohexanediaminotetraacetic acid,
It contains glycol ether diamine tetraacetic acid and salts thereof, phosphonocarboxylates, as well as persulfates, quinones and the like. In addition, alkali bromide, a rehalogenating agent such as ammonium bromide, borates, carbonates, and nitrates may be optionally contained. The fixing solution and the bleach-fixing solution may contain acetate, borate, ammonium or potassium alum bisulfite in addition to the fixing agent. If necessary, a bleaching accelerator is used in the bleaching solution, the bleach-fixing solution and their pre-bath.

Examples of the fixing agent include thiosulfates, thiocyanates, thioether compounds, thioureas, and a large amount of iodide salts, but the use of thiosulfates is common, especially ammonium thiosulfate. Is the most widely used. As a preservative for the bleach-fix solution, sulfite, bisulfite, sulfinic acid or carbonyl bisulfite adduct is preferable. The photographic processing liquid contains various substances as described above, and depending on the processing contents, contains the above substances in a considerably high concentration. The mixture of the waste liquid contains a great number of various substances, and contains a considerably high concentration as compared with the normal waste liquid.

Therefore, the photographic waste liquid has a high B in terms of water quality.
High iodine consumption including OD, COD, and silver,
It is characterized by high ammonium salt concentration and high salt concentration (carbonate, sulfate, thiosulfate), and color photographic processing waste liquid also contains iron salt, which can be treated by normal sewage (sewage) treatment. It is said that it can be carried out if the dilution is sufficient, but in practice, it is considerably difficult, a large amount of dilution water is required, and the treatment amount is remarkably increased. As an example of the photographic waste liquid, Table 1 shows an example of environmental characteristic data of the waste liquid from a typical minilab color negative processing and color paper processing.

[0026]

[Table 1]

In the waste liquid from the black and white developing solution, BO is further added.
Many have high D and COD. Since the photographic waste liquid has the composition as described above, various volatile substances are contained in the waste liquid when it is processed by a distillation method as known in order to reduce the volume of the waste liquid. As described above, these substances often enter the distillate and cannot be discharged. For example, since a color developer for silver chlorobromide color paper contains benzyl alcohol, the waste solution also contains the alcohol, and the alcohol has a relatively high vapor pressure, and therefore a large amount of it is contained in the distillate. And sometimes BOD 5,000p
It also becomes pm. The black and white developer contains ethylene glycol, diethylene glycol, and amines having relatively low boiling points, and brings about the same increase in BOD as described above.

Many fixing solutions contain ammonium thiosulfate, and in the waste liquid mixed with the developing solution, the pH rises, so that ammonia is mixed in the distilling solution. When the pH rises in this way, the problem of containing ammonia occurs. Further, sulfur dioxide and sulfidizing gas are mixed into the distillate from the waste liquid of the fixer and the bleach-fixer to lower the pH. As described above, when the photographic waste liquid is distilled, the water quality control factor substance having a low boiling point enters the distillate liquid depending on the type of the waste liquid, but the way in which the substance enters changes depending on the distillation conditions such as temperature and pressure. For example, when the color negative / paper mixed waste liquid is distilled, ammonia is volatilized and the pH of the distillate is 9, and the ammonia concentration is 2,000.
Although the concentration becomes 0 ppm, when the distillation is continued and the concentrated liquid becomes a solid residue, the distillate finally contains sulfur-based gas such as sulfurous acid gas up to 5,000 mg / liter or more. For details, see American Academy of Photography (SPSE).
Iwano et al.'S report of the 6th International Symposium on Photofinishing Technology (February 1990, Las Vegas).

Therefore, the distilled water obtained by distilling the photographic waste liquid cannot be discharged to the sewage or the river as it is. Further, since the photographic waste liquid is a waste liquid from the above-described processing liquid, its liquidity and composition greatly differ depending on which processing step the waste liquid is a main part of. For example, the mixed effluent from the fixing, bleach-fixing, washing, and stabilizing processing steps is alkaline, and ammonia or the like is easily generated when distilling the alkaline photographic processing waste solution. Is high, and it contains a considerable amount of ammonia. Further, the waste liquid from the processing steps of acid hardening fixing and low pH bleach-fixing is acidic, and when diluting this acid photographic processing waste liquid, sulfurous acid gas and the like are easily generated. Has a low pH and contains a considerable amount of sulfurous acid gas (in the form of sulfurous acid). Therefore, when such an alkaline or acidic primary distillate is redistilled as it is, the above-mentioned gas containing ammonia is generated.

In the above-mentioned distillation step of the present invention, the distillation is carried out under reduced pressure. And as the depressurizing condition, 10 to 500 mmHg is preferable, and particularly 10 to 100 m
mHg is preferred. Further, those distillations may be performed by two distillation apparatuses provided in the same tank or may be performed by parallel distillation apparatuses. Further, the distillation temperature is preferably lowered in order to minimize volatilization of contained components, specifically, it is preferably 80 ° C or lower, more preferably 70 ° C or lower, and particularly preferably 20 to 50 ° C. preferable. If the distillation temperature is lowered, sulfide will not enter the distillate. In the vacuum distillation according to the present invention, the following vacuum distillation apparatus is used. Typical vacuum distillation apparatuses include, for example, the following methods. In the present invention, any of these methods is used. It is applicable and any other type can be used.

A) Reduced pressure evaporation / distillation apparatus A method of condensing the vapor by reducing the pressure so that the evaporation amount is large even at room temperature or weak heating. Example: Model MPTU, A from Calfran, USA
PTU Italy's LED Italy WTS-E Further, a vacuum concentration device manufactured for general industrial use (for example, manufactured by Hisaka Seisakusho or Sasakura Seisakusho) can also be used for vacuum evaporation concentration of photographic waste liquid.

For condensation in the above apparatus, means such as air cooling, use of cooling surface by adiabatic compression and expansion of refrigerant, and water cooling can be used. In the above method c), the depressurization can be performed by applying any of various methods such as a vacuum pump, a water flow pump, and an ejector. In carrying out the method of the present invention, known bactericidal agents and antibacterial agents can be used in the waste liquid, if necessary, so that stable work can be performed for a long period of time. The method of the present invention is a so-called minilab, which is a small-scale developing laboratory, processing of microfilm in a place of office documentation, printing, platemaking,
It is suitable for small-scale photo processing plants such as color copiers. At the same time, it is effective to be carried out as a pre-stage of waste liquid treatment in a large-scale developing laboratory, a so-called large laboratory. It is also used at the processing site of a waste liquid recovery company.

That is, the method of the present invention can be applied to the following waste liquids according to the fields. 1) Printing plate making factory: black and white / color developing solution, fixing solution, bleaching solution, these are etching solution, reducing solution, paints, inks, organic solvents, PS plate processing waste liquid, photopolymer image material It may be a mixture of various discharged liquids such as a processing waste liquid and a tank cleaning liquid, and these can be collectively processed. 2) Color developer: black and white / color developer, fixer, bleach, bleach-fixer, image stabilizing bath, and discharge liquid of other processing baths The preferred embodiment is to collect and discharge the discharge liquid from each of the above baths. Then, flush the water as it is. When the countercurrent multi-stage water-saving type water washing or the method in which the stabilizing bath also serves as water washing, all the discharged liquids can be mixed and treated.

3) Office, store: Copying drawings from offices, drawings, etc. where documentation is performed using a printer processor for microfilm or a reader printer such as Mikle 1200 (trade name, manufactured by Fuji Photo Film Co., Ltd.) Effluent from a design office where printer processors are used, color copies are made, and in-store processors that perform instant prints are taken. 4) Intermediate base for waste liquid recovery processing 5) Centralized processing site where waste liquid is collected The amount of photographic waste liquid to be processed by the method of the present invention varies depending on the field to which it is applied, as long as it is a general developing station or a major printing factory. It is 100 liters to several m ^{3 a day} , but it is about 10 liters a day in a minilab, and a smaller amount in a microfilm copying processor or an X-ray room in a hospital. Therefore, the distillation apparatus used for it should also have a capacity compatible with it, and the model should be selected to suit the scale.

[0035]

In the present invention, the condensate is contacted with air,
By passing the ammonia-containing gas separated thereby through the catalyst packed bed, the ammonia is decomposed with extremely high efficiency,
Can be removed. Since a catalyst is used, the decomposition of ammonia is decomposed at a high rate at a low temperature,
High removal rate. Further, since the reaction temperature is not as high as in the case of thermal decomposition, the conversion rate to nitric oxide is very low, and therefore the problem of releasing NO _x does not occur.
Further, since the catalytic reaction device may be small in size, a simple device may be used, and it can be installed in a small developing device, which is practical. In the present invention, although the photographic waste liquid contains a large amount of many kinds of compounds, the condensate obtained from the photographic waste liquid mainly contains ammonia, acetic acid and the like for evaporating and concentrating under reduced pressure. Is reduced, the ammonia is removed by bringing the condensate into contact with air, and the ammonia-containing gas generated at that time mainly contains ammonia. Even if it is decomposed and removed, it does not adversely affect the action of the catalyst.

[0036]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. Example 1 Commercially available Fujicolor negative film Super G-
100, Super G-200, Super G-400, Super HG-1600 (above trade name, manufactured by Fuji Photo Film Co., Ltd.), Kodacolor negative Gold-100, Gold-
400, Gold-1600, (trade name, manufactured by Eastman Kodak Company), Conicolor negative DD-100,
DD-400, SR-1600, (trade names, manufactured by Konica Corporation) were mixed without any particular classification, and sequentially processed. Each processing was carried out as follows using an automatic processor FP-560B manufactured by Fuji Photo Film Co., Ltd. The treatment process and the treatment liquid composition are shown below.

(Processing step) Processing time Processing temperature Replenishment amount * Tank capacity Color development 3 minutes 5 seconds 38.0 ° C. 23 ml 17 liters Bleaching 50 seconds 38.0 ° C. 5 ml 5 liters Bleaching fixing 50 seconds 38.0 ° C. 5 liters fixed 50 seconds 38.0 ° C 16ml 5 liters water washed 30 seconds 38.0 ° C 34ml 3.5 liters stable (1) 20 seconds 38.0 ° C-3 liters stable (2) 20 seconds 38.0 ° C 20ml 20 liters Dry 1 min 30 sec 60 ℃ * Replenishment amount per 35m width of photosensitive material 1.1m (24E
x. (Equivalent to 1)

The stabilizing solution was a countercurrent system from the stabilizing step (2) to the stabilizing step (1), and the overflow solution of washing water was all introduced into the fixing bath. When replenishing the bleach-fixing bath, a cutout is provided on the bleaching tank of the automatic processor and on the top of the fixing tank so that all of the overflow solution generated by supplying the replenishing solution to the bleaching tank and the fixing tank is added to the bleach-fixing bath. I was allowed to flow in. The amount of developing solution brought into the bleaching step, the amount of bleaching solution brought into the bleach-fixing step, the amount of bleach-fixing solution brought into the fixing step, and the amount of fixing solution brought into the washing step were as follows. 2.5m per 1m
1, 2.0 ml, 2.0 ml, 2.0 ml. The crossover time is 6 seconds in all cases, and this time is included in the processing time of the previous step.

The composition of the processing liquid is shown below. (Color developer) Tank liquid (g) Replenisher (g) Diethylenetriaminepentaacetic acid 2.0 2.0 1-Hydroxyethylidene-1,1-diphosphonic acid 2.0 2.0 Sodium sulfite 3.9 5.1 Carbonic acid Potassium 37.5 39.0 Potassium bromide 1.4 0.4 Potassium iodide 1.3 mg-Hydroxylamine sulfate 2.4 3.3 2-Methyl-4- [N-ethyl-N- (β- (Hydroxyethyl) amino] aniline sulfate 4.5 6.0 Water was added to 1.0 liter 1.0 liter pH (adjusted with potassium hydroxide and sulfuric acid) 10.05 10.15

(Bleaching Solution) Tank Solution (g) Replenishing Solution (g) 1,3-Diaminopropane Ferric Acetate Ammonium Salt Monohydrate 130 195 Ammonium Bromide 70 105 Ammonium Nitrate 14 21 Hydroxyacetic Acid 50 75 Acetic Acid 40 60 1.0 liter by adding water 1.0 liter pH [adjusted with ammonia water] 4.4 4.4

(Bleaching Fixing Tank Liquid) A 15:85 (volume ratio) mixture of the above bleaching tank liquid and the following fixing tank liquid. (P
H 7.0) (Fixer) Tank solution (g) Replenisher (g) Ammonium sulfite 19 57 Ammonium thiosulfate aqueous solution (700 g / liter) 280 ml 840 ml Imidazole 15 45 Ethylenediaminetetraacetic acid 15 45 Water was added 1.0 liter 1.0 liter pH [adjusted with ammonia water and acetic acid] 7.4 7.45

(Washing Water) Tap water was used as an H-type strongly acidic cation exchange resin (Amberlite IR-produced by Rohm and Haas).
120B) and an OH type strongly basic anion exchange resin (Amberlite IR-400) are passed through a mixed bed column to adjust the concentration of calcium and magnesium ions to 3 m.
g / l or less, followed by sodium diisocyanurate dichloride 20 mg / l and sodium sulfate 1
50 mg / l was added. The pH of this solution is 6.5.
It was in the range of ~ 7.5.

(Stabilizer) Common to tank liquid and replenisher (unit g) Sodium p-toluenesulfinate 0.03 Polyoxyethylene-p-monononyl phenyl ether (average degree of polymerization 10) 0.2 Ethylenediaminetetraacetic acid disodium 0 .05 1,2,4-triazole 1.3 1,4-bis (1,2,4-triazol-1-ylmethyl) piperazine 0.75 Water was added to 1.0 liter pH 8.5

The overflow liquid in each tank of this automatic processor is transferred from the waste liquid storage tank to a vacuum evaporation concentration device (LED).
It was transferred to Italia Co. WTS-E150 type) and subjected to vacuum distillation to reduce the waste liquid volume (concentrated liquid volume) to 25% of the initial volume, and to obtain a distillate of an amount corresponding to the initial 75%. The ammonia concentration and pH in the distillate are as follows. Ammonia concentration: 1950ppm Acetic acid concentration: 100ppm pH: 8.9 This liquid cannot be discharged into sewage or rivers because of its high pH. Also, there are areas where the total nitrogen level is subject to regulations. In order to remove ammonia from the distillate, this distillate was prepared as shown in FIG.
Air contact (ammonia stripping) was performed using the following countercurrent wetting wall column having the structure shown in FIG. The temperature of the distillate was preheated to 56 ° C. and then the distillate was allowed to flow down the countercurrent wetting wall column to the packed bed. On the other hand, air was preheated to 56 ° C. and fed from the lower part of the tower to carry out gas-liquid countercurrent contact in the packed bed under the following conditions.

In FIG. 2, reference numeral 14 is a countercurrent wetting wall tower, the countercurrent wetting wall tower 14 has its outside kept warm by a heat insulating material 15, and the inside is filled with a lashing ring as a filling material. The distillate 12 is preheated by a preheater 13 and supplied from the top of the tower, and at the same time, air 17 is supplied from the bottom of the tower to an air supply pipe 18
It is introduced through and is subjected to ammonia stripping through internal lashing. The temperature is measured by a thermometer 16 provided above the countercurrent wetting wall tower 14.
The treated water flows out of the system through the treated water outlet pipe 19 at the bottom of the tower, and the air containing ammonia (ammonia-containing gas) is exhausted from the top of the tower.

Countercurrent Wet Wall Tower Specifications: Tower Height: 1.5m Inner Diameter: 0.4m Packed Bed Height: 1.0m Material: Vinyl Chloride Resin Filler: 6mm x 6mm Diameter Glass Rashi Ring Filling Volume: 1.3 liters Countercurrent wetting wall tower Operating conditions: Raw liquid flow rate: 1.76 kg / hr (superficial velocity: 1.400 kg / m ² hr) Gas flow rate: 2.05 kg / hr (superficial velocity: 1. 630 kg / m ² hr) Liquid-gas ratio (L / G): 0.93 Liquid-gas temperature: 56 ° C

Results: Ammonia concentration in treated water: 85 mg / l pH: 7.6 Effective removal of ammonia could be achieved with a relatively simple device. In addition, the ammonia-containing gas generated by air contact has an average concentration of 2500 ppm,
It is sent to the next ammonia decomposition step for processing. The ammonia decomposition process uses the experimental apparatus shown in FIG.
Into the above, 0.6 liter of a platinum catalyst (NS catalyst manufactured by JGC Universal Corp.) 6 in which platinum was supported on an alumina carrier was filled. The catalyst is heated by an electric heater 7 and the reaction temperature becomes 2
It was performed at 50 ° C. The temperature of the gas discharged from the catalytic reactor 5 is measured by the thermometer 9 and the heating by the electric heater 7 is controlled by the temperature controller 8, so that the temperature of the catalyst 6 in the catalytic reactor 5 is kept at the above temperature. I tried to keep it.

The ammonia-containing gas 1 is fed into the catalytic reactor 5 by the air pump 2 to cause the decomposition reaction of ammonia at a temperature of 250 ° C. The space velocity SV was 5000 (1 / hr) as the amount of ammonia-containing gas fed in at that time.
Met. The flow rate was adjusted by the flow meter 3. Further, the ammonia concentration at the inlet of the ammonia-containing gas is
A sample was taken and measured by an inlet gas sampling 4 provided in front of the catalytic reactor 5. The gas discharged from the catalytic reactor 5 was cooled by the gas cooler 10 and then a sample was taken by the outlet gas sampling 11 to measure the ammonia concentration and the like. The ammonia concentration in the outlet gas from the catalytic reactor in this reaction was as low as 13 ppm, and the ammonia leak rate was only 0.5%. Further, the NO _x concentration in the outlet gas was 13 ppm, and the conversion rate to nitric oxide could be stopped at 0.5%.

Example 2 The distillate of Example 1 was air contacted using the same countercurrent wetting wall column. The operating conditions are an operating temperature of 60 ° C. and a liquid gas ratio of 1.29. The treated water obtained by the treatment has an ammonia concentration of 160 mg / liter, and the contact air has an ammonia concentration of 4000 ppm. The ammonia-containing gas of this contact air was sent to the next ammonia decomposition step. In the ammonia decomposition step, the same apparatus as in Example 1 was used, and 0.6 liters of a copper / chromium catalyst (N201, manufactured by JGC Chemical Co., Ltd.) was charged as a catalyst. The ammonia-containing gas is fed into the catalytic reactor 5 to cause the decomposition reaction of ammonia at a temperature of 250 ° C. The amount of ammonia-containing gas fed at that time was 1000 (1 / h
r). The ammonia concentration in the outlet gas from the catalytic reactor in this reaction was as low as 80 ppm, and the ammonia leak rate was only 2.0%. Further, the NO _x concentration in the outlet gas was 140 ppm, and the conversion rate to nitric oxide could be stopped at 3.5%. This example is inferior to the case where the platinum catalyst of Example 1 is used, but the conversion rate to nitric oxide is still low and ammonia is effectively decomposed.

Example 3 Using the same apparatus as in Example 1, 0.6 liter of a titanium oxide catalyst (S145P manufactured by Sakai Chemical Co., Ltd.) was filled as a catalyst. The ammonia-containing gas having an ammonia concentration of 4000 ppm in Example 2 is fed into the catalytic reactor 5 to cause the decomposition reaction of ammonia at a temperature of 220 ° C. The amount of ammonia-containing gas fed in that case was 3500 (1 / hr) SV.
Met. The ammonia concentration in the outlet gas from the catalytic reactor in this reaction was as low as 40 ppm, and the ammonia leak rate was only 1.1%. The NO _x concentration in the outlet gas was 20 ppm, and the conversion rate to nitric oxide could be stopped at 0.5%. The conversion rate to nitric oxide is low and ammonia is effectively decomposed.

[0051]

INDUSTRIAL APPLICABILITY The present invention is capable of decomposing and removing the ammonia of the ammonia-containing gas generated when the condensate from the vacuum evaporation of photographic waste liquid is brought into air contact with high efficiency and low cost by a simple device. You can In the present invention, the reaction can be carried out at a low temperature because of using the catalyst,
Since it does not require a high temperature such as 800 to 1,000 ° C. used when thermally decomposing ammonia by the thermal decomposition method, it is very advantageous in terms of thermal economy. Further, it is possible to remove ammonia at a high rate with a small device. Therefore, since the leak rate of ammonia can be reduced, the gas can be processed at a high space velocity and can be discharged as a gas satisfying the standard that can be discharged to the atmosphere. Further, since the treatment temperature at the catalyst is low, the conversion rate to NO _x is low, and therefore the problem of NO _x release does not occur,
It is advantageous in terms of environmental issues. Further, the present invention is cost-effective because no chemical is used for removing ammonia. Since the apparatus used in this method can be small and simple, it can be installed in a developing station and is suitable for on-site processing. Further, since it is small in size and has a large processing capacity, it is also suitable for collecting photographic waste liquid, particularly developing waste liquid, from each developing place to a waste liquid processing place for intensive harmless processing.

[Brief description of drawings]

FIG. 1 shows a schematic diagram of an ammonia decomposition treatment apparatus used in an example of the present invention.

FIG. 2 is a schematic view of an air contact device for condensate used in an example of the present invention.

[Explanation of symbols]

 1 Ammonia-Containing Gas 2 Gas Pump 3 Flow Meter 4 Inlet Gas Sampling 5 Catalytic Reactor 6 Catalyst 7 Electric Heater 8 Temperature Controller 9 Thermometer 10 Gas Cooler 11 Outlet Gas Sampling 12 Distillate 13 Preheater 14 Countercurrent Wet Wall Tower 15 Heat Insulation Material 16 Thermometer 17 Air 18 Air supply pipe 19 Treated water outflow pipe

Claims (4)

[Claims] 1. A photographic waste liquid is evaporated and concentrated under reduced pressure, vapor generated at that time is condensed to separate the concentrated waste liquid and a dilute condensate, and the condensate is brought into contact with air to remove ammonia in the condensate. A method for decompressing photographic waste liquid under reduced pressure, which comprises decomposing ammonia by introducing an ammonia-containing gas into a catalyst-packed bed and contacting it with a catalyst. 2. The method for vacuum evaporation treatment of photographic waste liquid according to claim 1, wherein the temperature of the catalyst in the catalyst packed bed is 500 ° C. or lower. 3. The temperature of the catalyst in the catalyst packed bed is 150-4.
The method for vacuum evaporation of photographic waste liquid according to claim 1, wherein the temperature is 00 ° C. 4. The catalyst in the catalyst packed bed is platinum, copper.
4. The method for vacuum evaporation processing of a photographic waste liquid according to claim 1, wherein the method is selected from chromium and iron.