JPH03262594A - Treatment of photographic waste liquid - Google Patents

Abstract

PURPOSE:To efficiently lower COD value and BOD value by previously oxidizing and decomposing the photographic waste liquid wherein the concn. of bromide ions is >=0.1g/l and BOD/COD value is <=1.0 by iron powder and aqueous hydrogen peroxide and thereafter performing biological treatment. CONSTITUTION:The pH of the photographic waste liquid wherein the concn. of bromide ions is >=0.1g/l and BOD/COD value is <=1.0 is preferably regulated to about 7 or below. After iron powder is added thereto and the mixture is agitated, hydrogen peroxide is continuously added at about 5ml-5l per waste liquid 1l to oxidize the waste liquid. After oxidative reaction is completed, an alkali agent is added to regulate the pH to about 6.5 or more and the mixture is agitated for a specified time. Thereafter a polymeric flocculant is added and suspended solid is flocculated and settled and thereafter this ppt. is filtered and separated. Then biological treatment such as activated sludge treatment is performed and thereby clarified water wherein COD and BOD are lowered can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for treating photographic processing waste liquid, and more particularly to a method for rendering harmless photographic waste liquid having a high COD value.

(Prior art) Conventionally, methods for treating photographic waste include activated sludge method (for example, Tokko Sho!/-7λri No. 173 and Tokko Sho! l-7lij-ko, etc.), evaporation method (Tokko Sho!/-7λri No. Guar1ri34t7 and Tokko ShojA-43 Tata, etc.), electrolytic oxidation method (Tokko Sho!3-φ3μ7, etc.), ion exchange method (Tokko Show 6/ -J77θφ, Tokuko Shoyo 3-3♂3, etc.), reverse osmosis method (Tokkai Sho! O-Cocog 6, etc.)
3 etc.), chemical treatment method (JP-A No. 3-isizr,
Special Public Shoyo 7-37Jtt, Special Public Sho J/-114/7!
A, etc.) are known, but each has the following drawbacks.

For the activated sludge method, the BOD/COD value is /.

When attempting to treat photographic waste liquid that is small, such as less than O, considerable dilution is required, and the COD removal rate is only 30% or less, which is not a satisfactory method.

Electrolytic oxidation methods have high equipment costs and the electrodes are quickly contaminated. The ion exchange method and the reverse osmosis method can quickly become unusable for thick photographic waste liquids because the resin and membrane become fatigued. Furthermore, chemical treatment methods using hydrogen peroxide, persulfates, perhalogenates, anohalous acid, and hypohalous acid are known, but these methods are not suitable for photographic waste liquids with high COD concentrations. All of these methods have extremely low treatment efficiency and always end up using more chemicals than necessary.

Therefore, it is difficult to treat photographic waste liquid using the above method alone. A method has been proposed in which Fenton oxidation is performed followed by biological treatment, as is done in Publication No. 3-Koji ψ-tei and at the Nagoya Industrial Research Institute. However, the Br ion concentration is 0. When photographic waste liquid containing /z/1 or more is subjected to Fenton oxidation, Bre ions inhibit the oxidation reaction of OH radicals, and sufficient oxidative decomposition cannot be carried out.

Although this liquid originally has a small BOD/COD ratio, the BOD/COD ratio is still small because it is not sufficiently oxidized by Fenton oxidative decomposition. Therefore, even if biological treatment is performed thereafter, the COD and BOD removal rate will not improve.

(Problems to be Solved by the Present Invention) The purpose of the present invention is to process photographic waste liquid with a Br ion concentration of 0.1g71 or more and a BOD/COD value of /0.0 or less without being affected by Br ions. The goal is to oxidize and decompose waste liquid components to obtain extremely highly treated water.

(Means for Solving the Problem) As a result of various studies, the present inventors have found that the object of the present invention can be effectively achieved by using the following means.

That is, the present invention is a method for treating photographic waste liquid, which is characterized by performing oxidative decomposition using iron powder and hydrogen peroxide as a pretreatment when biologically treating photographic waste liquid.

Oxidative decomposition method using iron powder and hydrogen peroxide solution as pre-treatment (hereinafter referred to as iron powder method). As shown in Japanese Patent Application Publication No. Shojtr-Zi912, this method has better oxidation efficiency than Fenton oxidation method. . However, when applied to photographic waste liquid, the oxidation reaction is inhibited by Bre ions, similar to the Fenton oxidation method, and sufficient treatment cannot be achieved by using this method alone. However, it has been found that when this oxidation treatment is performed, biologically inert organic substances in the waste liquid are decomposed and the BOD/COD value increases. Furthermore, by using iron powder, heavy metals harmful to microorganisms used in biological treatment, such as silver in photographic waste liquid, can be recovered at the same time. This point is a major advantage when using the iron powder method rather than the Fenton method. Therefore, if this treatment liquid is subjected to biological treatment, an extremely high-quality treatment liquid with reduced COD and BOD values can be obtained. Therefore, the iron powder method is
The oxidation method is optimal as a pretreatment for biological treatment, and by combining the two, it is possible to realize a highly advanced photographic waste liquid treatment that has never been seen before.

Any known iron powder can be used in the present invention. Preferably, it is used in the presence of copper, for example, copper-coated iron powder (copper-coated iron powder)
is more preferred for the purposes of the present invention. As for the coating rate here! About 20% is preferable. In addition, the method using copper-coated iron powder is effective for separating photographic processing waste liquids and color photographic processing waste liquids (for example, waste liquids containing p-phenylenediamine color developing agents, organometallic iron complex salts, etc.). .

As the photographic waste liquid targeted by the present invention, as mentioned above, Br
E concentration of 0.1g773 or more and BOD/COD ratio of 1.0 or less are effective, but Bre concentration is especially 0.
, 1 g/1 or more, with a BOD/COD ratio of -r
Photographic waste liquids having -f'io, r or less, especially o, are suitable for the method of the present invention.

Next, the processing steps of the present invention will be explained.

(1) Adjust the pH of the photographic waste liquid to preferably 7 or less. More preferably 1 to 3.

The acid used here may be any of hydrochloric acid, sulfuric acid, and nitric acid. Further, the COD concentration of the photographic waste liquid is preferably 100
0~ljO,000ppm.

More preferably, a solution diluted to 1000 to 2.000 ppm is used.

(2) Next, add iron powder (for example, copper-coated iron powder) and stir. At this time, if necessary, the liquid temperature is increased to 300C or higher and an antifoaming agent is added. Here, it is preferable to use an antifoaming agent such as a silicone emulsion because foaming can be prevented.

(3) Next, hydrogen peroxide is added continuously. The amount added varies depending on the COD concentration of the waste liquid, but it is added per liter of waste liquid.
It is preferable to use about mJl-61.

The oxidation reaction time is usually 30 minutes to 20 minutes.

(4) After the oxidation reaction is completed, an alkaline agent is added to adjust the pH to preferably 7 or more, more preferably r, z or more. As an alkali agent, caustic soda, slaked lime, or a mixture thereof, preferably slaked lime in the form of milk, is added to improve processing efficiency and accelerate aggregation.

(5) After stirring for a certain period of time (for example, io~30 minutes), add a polymer flocculant to flocculate, stop stirring, and after settling, r
Perform over-separation.

These series of operations are automatically performed using a continuous or batch type device.

(6) After filtration, clear water with reduced COD and BOD can be obtained by performing biological treatment (for example, activated sludge treatment).

The biological treatment in the present invention includes activated sludge method, lagoon method, sprinkled bed method, rotating disk method, and other biological catalytic oxidation methods.

For specific methods such as these biological treatments, please refer to "Activated Sludge Method Maintenance and Management Techniques" by Toshibe Sakurai and Takashi Sudo (editors) (published by Science and Technology Development Center), "New Activated Sludge Method" by Sho Hashimoto and Takashi Sudo (editors) (published by the Industrial Water Research Association), etc.

In this way, according to the strong oxidation method using copper-coated iron powder, a liquid that is more easily biodegradable than the conventional oxidation method can be obtained, so that further reduction of COD and BOD by living organisms can proceed efficiently.

Furthermore, although sedimentation using a polymer flocculant under alkaline conditions after oxidation treatment is effective in removing iron components,
Tokukaisho for information on iron removal methods! To 0-I! FAF, JP-A-32-12'/-7! r, Japanese Patent Application Publication No. 3μm4j/91r,
Tokukai Akira! 6-ta 339/, JP-A-F14zt-i J J
r J' A, JP-A-Sho to-xout2! A method of neutralizing ferrous iron and then oxidizing and precipitating it, a method of converting it into ferrite and magnetically separating it, and a method of magnetically separating ferrous iron described in JP-A-Kokai Shobu/-/2cojft and JP-A-Kokai Sho1μ5r3yr. high pH
Either a method of precipitating and removing the iron chelate or a method of precipitating and removing the iron chelate or titanium iron complex under high pH treatment may be employed.

The iron powder used in the present invention is commercially available, for example, from Wako Tsumugi Pharmaceutical Co., Ltd.

The polymer flocculants used in the present invention include those having anionic, nonionic, or cationic charges. These neutralize the surface charge of particles suspended in water that are charged with opposite ions, destabilizing individual particles and promoting the coagulation phenomenon.

Next, adsorption by the active functional group to the particles occurs, and the bridging effect between the υ particles leads to aggregation of the suspended particles, further promoting the formation of huge flocs. As the material of the polymer flocculant, a copolymer of acrylamide or acrylic acid is commonly used.

The photographic waste liquid used in the method of the present invention is as follows.

This is a processing solution produced when a silver halide photosensitive material is developed. Here, the photosensitive materials include color photosensitive materials as well as black and white photosensitive materials. For example, in addition to color H/R-, color reversal paper, color negative film for photography, color reversal film, negative or positive film for movies, direct positive color photosensitive materials, X-ray film, photosensitive materials for printing, microfilm, and photosensitive materials for photography. Examples include black and white film.

Moreover, the following can be mentioned as a processing liquid used for development processing.

The color developing solution used for developing the photosensitive material is preferably an alkaline aqueous solution containing an aromatic primary amine color developing agent as a main component. Aminophenol compounds are also useful as color developing agents, but p-phinidinediamine compounds are preferably used; typical examples include 3-methyl-ψ-7mi/-N, N-diethylaniline, 3-methyl-tei-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methylder-amino-N
-ethyl-N-β-methanesulfonamidoethylaniline, 3-methylder-amino-N-ethyl-N-β-
Examples thereof include methoxyethylaniline and their sulfates, hydrochlorides, and II'1p-)luenesulfonates.

One or more of these compounds can be used in combination depending on the purpose.

The color developer may contain pH buffering agents such as alkali metal carbonates, borates or phosphates, bromide salts, iodide salts,
Development inhibitors such as benzimidazoles, benzothiazoles or mercapto compounds-! It generally contains antifoggants or antifoggants. Hydroxylamine, diethylhydroxylamine, sulfite hydrazines, phenyl semicarbazides, triethanolamine, catechol sulfones 2, and ethylenediamine (l, a-diazabicyclo[2゜2.2])
various preservatives such as octane), ethylene glycol,
organic solvents such as diethylene glycol, benzyl alcohol, polyethylene glycol, quaternary ammonium salts, development accelerators such as amines, dye-forming couplers, fogging agents such as competing couplers sodium boron hydride, phenyl-3-pyrazolidone, etc. Auxiliary developing agents, viscosity imparting agents, various chelating agents such as aminopolycarboxylic acid, aminopolyphosphonic acid, alkylphosphonic acid, phosphonocarboxylic acid, ethylenediamine acetic acid, nitrilotriacetic acid, diethylenetriamine Pentaacetic acid, cyclohexanediaminetetraacetic acid, hydroxyethyliminodiacetic acid, /-hydroxyethylidene-
/,/-diphosphonic acid, nitrilo-N,N,N-)rimethylenephosphonic acid, ethylenediamine-N,N,N'.

Representative examples include N'-tetramethylenephosphonic acid, ethylene glycol (0-hydroxyphenylacetic acid), and salts thereof.

When carrying out reversal processing, black and white development is usually performed and then color development is performed. This black and white developer contains known black and white developing agents such as dihydroxybenzenes such as hydroquinone, 3-pyrazolidones such as /-phenyl-3-pyrazolidone, and aminophenols such as FiN-methyl-p-aminophenol. Alternatively, they can be used in combination.

The pH of these color developing solutions and black and white developing solutions is generally 7 to 7. The amount of replenishment of these developers depends on the color photographic material to be processed, but it is generally
jl per square meter of optical material, and by reducing the bromide ion concentration in the replenisher,
It can also be made less than 0m1. When reducing the amount of replenishment, it is preferable to prevent evaporation of the liquid and air oxidation by reducing the area of contact with the air in the processing tank.

Additionally, the amount of replenishment can be reduced by using means for suppressing the accumulation of bromide ions in the developer.

After color development, the photographic emulsion layer is usually bleached.

The bleaching process may be carried out simultaneously with the fixing process (bleach-fixing process) or separately. Furthermore, in order to speed up the processing, a processing method may be used in which bleaching is followed by bleach-fixing. Furthermore, treatment with two consecutive bleach-fixing baths, fixing treatment before bleach-fixing treatment, or bleaching treatment after bleach-fixing treatment can be carried out as desired depending on the purpose. For bleaching agents, for example, iron (m), cobalt (I)
II), compounds of polyvalent metals such as chromium (Vl), copper (If), peracids, quinones, nitro compounds, etc. are used.

Typical bleaching agents include ferricyanide: dichromate; organic complex salts of iron (III) or cobalt (ilI), such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediamine acetic acid, methyliminodiacetic acid, /, 3-diaminoacetic acid, etc. Aminopolycarboxylic acids such as propanetetraacetic acid, glycol ether diamine tetraacetic acid, or complex salts of citric acid, tartaric acid, malic acid, etc.;
Persulfates; bromates; permanganates; nitrobenzenes and the like can be used. Among these, aminopolycarboxylic acid iron (III) complex salts and persulfates, including ethylenediaminetetraacetic acid iron (i[[) complex salts, are preferred from the viewpoint of rapid processing and prevention of environmental pollution. Furthermore, Amitsubo +7
Iron(III) carboxylate complexes are particularly useful in both bleach and bleach-fix solutions.

The pH of the bleach solution or bleach-fix solution using these aminopolycarboxylic acid iron (III) complex salts is normal! ,! ~r, but it is also possible to process at an even lower pH for speeding up the process.

A bleach accelerator may be used in the bleaching solution, bleach-fixing solution, and their prebaths, if necessary.

Specific examples of useful bleach accelerators are described in U.S. Patent No. 3. J, No. 1111, West German Patent No. 1. Kota 0. r/ko issue, Tokukai Sho! 3-taj, No. 430, Research Disclosure A/7. / Koji (7)
Compounds having a mercapto group or a disulfide bond described in JP-A-Sho! (July 772) and others: θ-no≠o, i Thiazolidine derivative described in Koji issue; US Patent No. 3,70
6. Thiourea derivatives described in Jr. No. 7; JP-A-Sho! j-
/A, 23! West German Patent No. 2゜71
Polyoxyethylene compounds described in Japanese Patent Publication No. 11.1730; polyamine compounds described in Japanese Patent Publication No. Sho φj-1134; bromide ions, etc. can be used. Among them, compounds having a mercapto group or a disulfide group are preferred from the viewpoint of having a large promoting effect, and are particularly preferred in US Pat. No. 11, West German patent No. 1゜-zyo, No. 1ris, JP-A-Sho! 3-
Preferably, the compounds described in TAJ, tJO No. Additionally, U.S. Pat.

jt32,1! Compounds described in No. ψ are also suitable. These bleach accelerators may be added to the photosensitive material. These bleach accelerators are particularly effective when bleach-fixing color light-sensitive materials for photography.

Examples of fixing agents include thiosulfates, thiocyanates, thioether compounds, thioureas, and large amounts of iodide salts, but thiosulfates are commonly used, with ammonium thiosulfate being the most widely used. Can be used for Preservatives for the bleach-fix solution are preferably sulfites, bisulfites, sulfinic acids, or carbonyl bisulfite adducts.

The silver halide color photographic light-sensitive material of the present invention is generally subjected to water washing and/or stabilization steps after desilvering treatment.

The amount of water used in the washing process depends on the characteristics of the photosensitive material (for example, depending on the materials used such as couplers), the application, the temperature of the washing water, the number of washing tanks (number of stages), the replenishment method such as countercurrent or forward flow, and various other conditions. Can be set over a wide range. Among these, the relationship between the number of washing tanks and the amount of water applied to the multistage countercurrent method is as follows.
Urnal of the 5ociety of M
tionPicture and Te1evisi
on Engineers Volume 1μ, P, φr-
It can be determined by the method described in 2z3 (Tri!! Year! Month issue).

According to the multi-stage countercurrent method described in the above-mentioned literature, the amount of water used for washing can be significantly reduced, but this increases the residence time of the water in the tank, causing bacteria to propagate and the generated suspended matter to be used as a material for photosensitive materials. Problems such as adhesion may occur. In the processing of the color photosensitive material of the present invention, as a solution to such problems,
The method for reducing calcium ions and magnesium ions described in JP-A-J/-/3/, tJ2 can be used very effectively. In addition, chlorine-based disinfectants such as inthiazolone compounds and thiabendazoles, chlorinated sodium incyanurate, and other benzotriazoles described in JP-A No. 7-lr and J-g. It is also possible to use the disinfectants described in "Chemistry of Microorganisms,""Microbial Reduction, Sterilization, and Anti-Mold Technology" by the Hygiene Technology Research Institute, and "Encyclopedia of Antibacterial and Antifungal Agents" by the Japan Anti-Sodium and Anti-Mold Research Institute.

The pH of washing water in processing photosensitive materials is μ-7, preferably j-t. Furthermore, instead of washing with water, the photosensitive material can be directly processed with a stabilizing solution.

Regarding such stabilization treatment, Japanese Patent Application Laid-Open No. 7-1.
! No. 4Lj! I-/4'.

? All known methods described in No. 3μ, No. 60-220, 3413 can be used.

Further, following the water washing treatment, a further stabilization treatment may be carried out, such as a stabilizing bath containing formalin and a surfactant, which is used as a final bath for color photosensitive materials for photography. .

Various chelating agents and antifungal agents can also be added to this stabilizing bath.

The spent processing waste liquid is usually treated as described above after silver recovery. Depending on the case, the above-described treatment may be performed without recovering the silver.

In addition, when performing the above-mentioned processing, it may be carried out after forming a mixture of a developer, a bleach solution, a fixer, a bleach-fixer, washing water, a stabilizer, etc., or a developer, a bleach, a fixer, etc. The water may be separated from washing water, stabilizing liquid, etc., and the former may be subjected to the treatment of the method of the present invention.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Examples/■ Processing photographic waste liquid by iron powder method (color photographic processing kit CN-/7, cp-
PS developer, bleaching solution, fixer, washing solution, and black and white photo processing killer) was treated as raw water. B at this time
The r ion concentration was θ, r g/13.

300 ml of this raw water was placed in a beaker, sulfuric acid was added thereto to adjust the pH to J, and then copper-coated iron powder/g was added with sufficient stirring. Next is 3! Initial COD of hydrogen peroxide solution
After addition, the solution was added in an amount of 2 equivalents, followed by stirring for to minutes. Thereafter, slaked lime was added to adjust the pH, and after stirring for 70 minutes, a polymer flocculant was added to flocculate, and the resultant liquid F was analyzed and the results are shown in Table 7-■. Na button, Fe
When the concentration of Cu and Fe was measured, the Fe# concentration was 3 ppm or less, and the Cu concentration was below the detection limit.

(2) Activated sludge treatment Water treated by the iron powder method was diluted to a COD value of approximately f00 ppm, and then activated sludge treatment was performed.

The results are shown in Table 1-■.

(Comparative Example 1) (1) Processed photographic waste liquid by Fenton oxidation method was diluted to a COD value of ioooooppm and treated as raw water. After adding phosphoric acid to 200ml of this raw water to adjust the pH to 3, add ferrous sulfate! g
Added. Next, while stirring thoroughly, 3! Add hydrogen peroxide solution in an amount of 2 equivalents to the initial COD value, then add alkali to adjust the pH to 0 to precipitate iron.
The results of analysis of the R-liquid passed through this are shown in Table/-■.

■ Activated sludge treatment The water treated by the Fenton oxidation method has a COD value of approximately g00pp.
After diluting to mVC, activated sludge treatment was performed.

The results are shown in Table 1-■.

(Comparative Example λ) (2) Processing by NaOα oxidation method Photographic waste liquid was diluted to a COD value of about 110,000 pp and treated as raw water. This raw water 10θm1
3, set the pH to /l, and Na0Q! ! Solution to initial CO
It was added in an amount of 2 equivalents based on the D value. Thereafter, calcium chloride was added at lOg/l, a flocculant was added to precipitate iron, and the filtered liquid was analyzed. Table 1 shows the results.
− Shown in ■.

■ Activated sludge treatment NaOα oxidized treated water has a COD value of approximately z o o pp
After diluting the solution to a concentration of m, activated sludge treatment was performed.

The results are shown in Table 1-■.

From the values of the present invention (Table 1-■), Comparative Example/(Table/-■), and Comparative Example 2 (Table 1-■), the present invention has COD, BOD
It can be seen that this is very effective in reducing the value.

In addition, the BOD/COD value of water treated with the iron powder method is higher than that of the Fenton method and the Na0Qi method, and it is thought that a large amount of material that is easily decomposed by living organisms is generated. The combination of legal oxidation and biological treatment is shown to be effective.

Example The photographic waste liquid used in Example 1 was treated by changing the concentration of Br ions. Chemical oxidation treatment and biological oxidation treatment are Example 1
I did it in the same way. The results are shown in Table 2.

Table 2 (Unit: mg/l) As is clear from Table 2, the present invention has a higher Br
When the ion concentration is 0,0/g/73 or higher, COD and BO can be adjusted without being affected by Bre ions.
D can be reduced.

(Effects of the present invention) When the method for treating photographic waste liquid of the present invention is used, the Br ion concentration is high (even photographic waste liquid with a small BOD/COD value has COD
It is possible to produce treated water with highly reduced values and BOD values.

Claims (1)

[Claims] Br^■Ion concentration is 0.1g/l or more, BOD/CO
A method for treating photographic waste liquid, which comprises carrying out oxidative decomposition using iron powder and hydrogen peroxide as a pretreatment when biologically treating oxidizable substances in photographic waste liquid having a D ratio of 1.0 or less.