JP2709845B2 - Automatic developing apparatus excellent in water saving efficiency and wastewater treatment method using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an automatic developing apparatus for a silver halide black-and-white photosensitive material, and more particularly, to an automatic developing apparatus having a drainage treatment means for washing water and excellent in water saving efficiency. And a wastewater treatment method using the device.

[Prior Art] At present, development processing of a silver halide light-sensitive material is generally performed using an automatic developing machine, and such an automatic developing machine generally includes developing, fixing, washing and drying. The photosensitive material that has been subjected to the developing and fixing processes is subjected to a washing step, in which a processing solution component in the preceding step, particularly a fixing solution component, contained in the material is washed away. If the washing is insufficient, especially in a black-and-white silver halide photosensitive material, performance problems such as deterioration of an image with time due to a residual fixing solution component in the material occur. Therefore, it is necessary to perform sufficient rinsing to sufficiently remove the residual fixing solution components in the photosensitive material. However, as described above, sufficient rinsing cannot be performed with the amount of rinsing water contained in the rinsing tank in the automatic developing machine. Met. For this reason,
At present, tap water is always supplied at the time of rinsing treatment, and the overflowing rinsing water is drained to the sewer as it is at present.

Under the circumstances as described above, in recent years, from the viewpoint of resource saving and reduction of production cost, the demand for water saving at the time of washing of the automatic developing machine has been increasing, and the demand for technical improvement accompanying this has been increasing. In other words, problems such as land subsidence in urban areas, rising water and sewage charges due to capital investment for lagging sewage treatment facilities compared to those in Europe and the United States, and water cuts due to specific weather conditions in summer in specific areas Demands for saving flushing water in order to cope with such problems are increasing in recent years, due to the recent increase in the amount of processing at plate-making shops and the problem of total wastewater control.

[Problems to be Solved by the Invention] In response to the above-mentioned demands for water saving, an anhydrous washing / no-pipe system or a countercurrent washing method in which chemical treatment is carried out instead of the conventionally proposed washing treatment is performed by the current black-and-white method. For the automatic development of silver halide photosensitive materials, especially for printing plate making, the equipment becomes complicated and large, such as an increase in processing tanks. As a result, the processing line length becomes longer and the processing time of the photosensitive material becomes longer. ,
From the viewpoint of speeding up processing accompanying mass processing in recent years, the direction is completely backward and cannot be applied. Furthermore,
In order to speed up the processing in such an apparatus as described above, it is necessary to further increase the processing line speed. In such a case, however, the physical load on the photosensitive material increases, and for example, the film of the photosensitive material Problems such as flaws and peeling of the surface, and charging of the photosensitive material due to friction occur.

Therefore, as one method, a method is conceivable in which a water tank for storing washing water is provided in the vicinity of the washing tank separately from the washing tank for performing the washing processing, and the washing water is circulated between the water tank and the washing tank. However, according to this method, the concentration of the components of the developer, fixer, and components eluted from the photosensitive material such as dyes, dyes, surfactants, and gelatin, which are carried into the washing water by the photosensitive material to be processed, are processed. Increase as the volume increases,
In particular, in recent large-scale treatment, the value of iodine consumption as a legally defined water quality standard is exceeded in a short time, and a problem in drainage remains. That is, a method that simultaneously satisfies the problems of water saving efficiency and wastewater treatment has not been found yet.

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide an automatic developing apparatus capable of improving water saving efficiency and purifying contaminated washing water to the extent that it can be drained.

A second object of the present invention is to provide an automatic developing apparatus having a wastewater treatment means which is compact and has improved maintenance and cost.

Further, a third object of the present invention is to provide a method for treating wastewater of contaminated rinsing water which is generated with an improvement in water-saving efficiency.

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, the object of the present invention was to provide at least a silver halide comprising a developing unit, a fixing unit and a washing unit. In the automatic developing apparatus for black-and-white photosensitive materials, the washing section includes at least washing means for washing the photosensitive material, and water containing used washing water drained from the washing means as washing water supplied to the washing means. Water storage means for temporarily storing water; circulating means for circulating rinsing water in the rinsing means and rinsing water in the water storing means between the rinsing means and the water storing means; and rinsing water circulated by the circulating means. A purifying agent supplying means for supplying a purifying agent to the water storage means when the contamination concentration of the water exceeds a predetermined value; and a draining means for draining at least a part of the washing water in the water storing means after supplying the purifying agent. Especially When the silver halide black-and-white photosensitive material is processed using the automatic developing apparatus and the silver halide black-and-white photosensitive material using the automatic developing apparatus, if the contamination concentration of the circulating washing water exceeds a predetermined value, purification is performed. A purifying agent supplied from the agent supply means to the water storage means to purify the washing water in the water storage means, and then draining at least a part of the washing water in the water storage means by the drainage means. It has been found that this can be achieved by providing.

Hereinafter, an automatic developing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram schematically showing an example of a water washing section of the automatic developing apparatus of the present invention. According to FIG. 1, the washing section of the developing device of the present invention comprises a washing tank 1 for processing a photosensitive material.
A water tank 2 provided in the vicinity of the water tank 1 for storing therein water for refilling the water tank 1 and water for overflowing from the water tank 1 due to the replenishment;
Circulating means 3 for replenishing the rinsing water to the rinsing tank 1 and supplying overflow water from the rinsing tank 1 to the water storage tank 2; When the pressure exceeds the limit, the purifying agent is automatically supplied to the water storage tank 2 and the purifying agent is supplied to the purifying agent supply tank 4 for purifying the water to a drainable value.
And discharge means 5 for discharging at least a part of the washing water in the water storage tank 2 after the supply of the purifying agent.

That is, at the start of the developing process, the washing tank 1 and the water tank 2 are filled with unused washing water, and then the developed and fixed photosensitive material is washed in the washing tank 1, and the water is stored in accordance with the processing amount. The washing water is automatically replenished from the tank 2 and, as a result, the used washing water overflowing from the washing tank 1 is sent to the water tank 2 without being drained as it is conventionally, and is temporarily stored. As the throughput increases, the circulation is repeated, whereby the washing water in the washing tank 1 and the water tank 2 is carried in by the photosensitive material. Since the water is contaminated by the components, it is necessary to drain all or at least a part of the washing water in the water tank 2 and replace it with fresh washing water. However, in particular, when the degree of contamination exceeds the drainage standard, drainage to the sewer becomes impossible. Therefore, it is necessary to always detect the degree of contamination of washing water and keep its concentration within an allowable range. For this reason, the concentration of contaminants in the washing water can be determined by either method,
Preferably, the washing water in the water storage tank 2 is measured by using a pollutant concentration measuring means, and the purifying agent is automatically supplied from the purifying agent supply tank 4 based on the measured value, and the washing water in the water storage tank 2 is allowed. Purify to a value. Thereafter, at least a part of the purified washing water is drained by the drainage means 5. The washing water in the water storage tank 2 may be entirely drained, or only one part may be drained and replaced with fresh washing water to be mixed and used.

In the present invention, the contaminant concentration of the washing water is a fixing liquid component which is considered to have the greatest influence on the iodine consumption since it is considered that it is necessary to satisfy the iodine consumption regulation because the sewerage is discharged. It can be considered as the concentration of thiosulfate ions such as certain ammonium thiosulfate and sodium thiosulfate.

As the purifying agent used in the present invention, an oxidizing agent is used, and a metal or nonmetal oxide, an oxide acid-based acid or a salt thereof, a peroxide, and a compound containing an organic acid-based compound are preferably used. As the acid-based acid, sulfuric acid, nitrous acid, nitric acid, hypochlorous acid, and the like are preferable in that the purpose is to decompose the fixing solution component brought into the used washing water in the water storage tank, and as the peroxide, Preferably, hydrogen peroxide solution, Fenton's reagent and the like are used. Also, ozone is preferably used.

For example, when the thiosulfate ion concentration of the washing water in the water tank 2 exceeds the value corresponding to the reference value of the iodine consumption, these purifying agents can be added according to the concentration, and diluted with water or the like. Then, it is added to the water storage tank 2 from the purifying agent supply tank 5 arranged adjacent to the water storage tank 2, but usually it is automatically added from the supply tank by a constant amount as needed, preferably in several hours. It is added to the water storage tank 2 in such a form that the supply valve is opened and dropped automatically at a rate of about one degree. The amount of addition can be determined by experiments or the like according to the thiosulfate ion concentration in the washing water.

As means for supplying a purifying agent in a fixed amount according to the thiosulfate ion concentration and automatically purifying the purifier according to the present invention, OR means
A method is possible in which the ORP value is measured with a P (redox potential) electrode and the purifying agent is automatically added based on the measured ORP value.

Specifically, a predetermined concentration of sodium thiosulfate solution is
After adjusting to pH 4 or pH 7, sodium hypochlorite is added, and the iodine consumption, KMnO ₄ consumption, and ORP value are measured to determine the amount of the purifying agent to be added. That is, for example, 0.03
When sodium hypochlorite is added to each of the N-Na ₂ S ₂ O ₃ solutions of pH 4 and pH 7, the ORP value of the first wave suddenly rises in the solution of pH 7 at a certain amount. Seen,
This coincided with the lowest value of iodine consumption. This is S ₂ O ₃
^2- indicates that the whole amount was oxidized. Further addition of sodium hypochlorite leads to the onset of the second wave of pH 7 solution and pH 4
A sharp rise of the solution is observed. Thus, in the neutral or acidic region, the rise of the ORP value is used to increase the value to +500.
Purification can be performed automatically by adding sodium hypochlorite until it reaches ~ 800 mV. By such a method, the amount of the purifying agent to be added can be determined by measuring the ORP value in various cases.

The ORP electrode may be installed in a water storage tank, and may be measured continuously or as needed, or may be measured by inserting the ORP electrode into the water storage tank as needed. Alternatively, the measurement value may be used in a circulation system outside the water storage tank, in a washing tank, or the like, and the measured value may be substituted for the measurement value in the water storage tank.

The measured value is automatically or artificially fed back to the purifying agent supply means, and, for example, by operating an electromagnetic on-off valve or the like, a necessary amount of the purifying agent can be supplied to the flush water in the water storage tank. Also, as another method of measuring the concentration of contamination,
There is a method of measuring the area of the processed light-sensitive material and substituting it. That is, since thiosulfate ion, which is a main contaminant, is a component carried by the processed light-sensitive material, its amount is considered to substantially correspond to the amount of the processed light-sensitive material, that is, the total area. Therefore, the concentration of contamination when a predetermined amount of photosensitive material is processed by an experiment and the amount of the purifying agent required to purify the concentration to a predetermined value are determined in advance, and the processing is performed using the result. It is sufficient to measure and calculate the total area of the light-sensitive material and supply a corresponding amount of the purifying agent.

As such a method, specifically, a light-sensitive material is detected by a sensor provided near a light-sensitive material insertion port of an automatic developing machine,
The total area of the processed light-sensitive material is counted by a counter connected to the sensor based on the information of the sensor. When the counted total area exceeds a value corresponding to a predetermined contamination concentration, a predetermined amount of a purifying agent is supplied to the water tank based on the experimental value. At this time, the experimental values are input in advance,
A system for calculating and automatically supplying the amount of the purifying agent corresponding to the total area value may be provided in the apparatus,
When the total area counter exceeds a predetermined value, an alarm sounds, and the alarm may be supplied artificially based on an experiment.
In the water storage tank, a usual well-known stirring means may be provided to promote purification.

By adding the purifying agent as described above, a predetermined value,
At least a part of the washing water purified to a value satisfying at least the drainage standard is drained by the drainage means 5.
The drainage means has, for example, an electromagnetic valve and can be opened and closed automatically. However, the valve may be opened automatically after the supply of the cleaning agent, or automatically or artificially after the supply or purification of the cleaning agent is confirmed. It may open and drain.

As the washing means of the automatic developing apparatus of the present invention, various conventionally known washing tanks and washing methods can be used. Further, water containing various additives known in the art can be used as washing water. In particular, the washing water provided with a fungicide is effectively used for preventing the generation of scale in the water stagnated in the water storage tank.

Examples of such antifungal means include an ultraviolet irradiation method described in JP-A-60-263939, a method using a magnetic field described in JP-A-60-263940, and an ion-exchange resin described in JP-A-61-131632. No. 60-253807, 60
-295894, 61-63030, and 61-51396 using the antibacterial agent can be used.

Furthermore, LEWest “Water Quality Criteria” Photo S
ci & Eng.Vol.9 No.6 (1965), NWBeach “Microbiolog
ical Growths in Motion-Picture Processing "SMPTE J
ournal Vol.85, (1976) .RODeegan, “Photo Processi
ng Wash Water Biocides “J.Imaging Tech.Vol.10, No.6
(1984) and JP-A-57-8542, JP-A-57-58143, and JP-A-57-58143.
-105145, 57-132146, 58-18631, 57-9
No. 7530, antibacterial agents described in Nos. 57-157244 and the like,
Anti-binders, surfactants and the like can be used in combination.

Furthermore, RTKreiman's J.Image, Tech10,
(6) Isothiazoline compounds described in 242 (1984), RESEARCH DISCLOSURE Vol. 205, Item 20526 (1981)
Compounds, described in Vol. 228, Item 22845 (April, 1983), compounds described in Japanese Patent Application No. 61-51396, and the like. Can be used in combination as a bacteriostatic agent (Microbiocide).

Further, specific examples of the anti-binder include phenol, 4-chlorophenol, pentachlorophenol, cresol, o-phenylphenol, chlorophen, dichlorophen, formaldehyde, glutaraldehyde, chloroacetamide, p-hydroxybenzoate,
2- (4-thiazoline) -benzimidazole, benzisothiazolin-3-one, dodecyl-benzyl-dimethylammonium chloride, N- (fluorodichloromethylthio) -phthalimide, 2,4,4'-trichloro-2'-hydro Oxydiphenyl ether and the like can be mentioned.

In addition, a method of performing treatment while performing various stirring. Methods such as the use of a washing accelerator, the supply of washing water according to the processing area of the photosensitive material, and the use of a squeeze for reducing carryover to the washing tank can also be used in combination.

The water tank 2 in the present invention can be made of vinyl chloride containing an antibacterial agent or the like, or a tank whose inside is nylon-processed, as the material of the tank, from the viewpoint of preventing water scale and corrosion.

As the circulating means in the present invention, for replenishing the washing water from the water tank 2 to the washing tank 1, for example, when a photosensitive material is inserted into an automatic developing machine, it is detected by a sensor, whereby the water is automatically removed from the water tank 2. An electromagnetic valve design in which the washing water is supplied to the washing tank 1 and the supply of the washing water is stopped when the photosensitive material is not detected may be used. At this time, it is preferable to forcibly transfer the washing water by a high-pressure pump, and the replenishing washing water amount is preferably 3 l / min to 8 l / min.

Further, the washing water overflowing from the washing tank 1 due to the above replenishment is sent to the water tank 2 as it is through a pipe connected to the water tank 2 and is temporarily stored therein.

As described above, the concept of performing the wastewater treatment while increasing the water saving efficiency by providing the water storage tank as in the present invention to circulate and use the washing water and further purifying and draining the contaminated washing water to increase the water saving efficiency is considered by the present inventor. Are found for the first time as a result of earnest research and are not found at all in the prior art.

The silver halide light-sensitive material applicable to the automatic developing apparatus of the present invention is a black-and-white light-sensitive material, and particularly includes a black-and-white negative film, a black-and-white reversal film, an X-ray film, a copying film, a printing film, and a gravure film.

As for the developing section, the fixing section and the drying section of the automatic developing apparatus of the present invention, all conventionally known various systems can be used.

In the black-and-white developer used in the present invention, a combination of dihydroxybenzenes and 1-phenyl-3-pyrazolidones is preferably used as a developing agent. Of course, besides this, p-
It may contain an aminophenol-based developing agent.

As the dihydroxybenzene developing agent used in the present invention, hydroquinone, chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dichlorohydroquinone, 2,3-dibromohydroquinone,
Although there are 2,5-dimethylhydroquinone and the like, hydroquinone is particularly preferred.

Examples of the developing agents of 1-phenyl-3-pyrazolidone or a derivative thereof include 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, and 1-phenyl- 4,4-dihydroxymethyl-3-pyrazolidone and the like.

Examples of p-aminophenol-based developing agents include N-methyl-p-aminophenol, p-aminophenol, and N-methylphenol.
(Β-hydroxyethyl) -p-aminophenol, N
-(4-hydroxyphenyl) glycine, 2-methyl-
Although there are p-aminophenol, p-benzylaminophenol and the like, N-methyl-p-aminophenol is preferable.

The developing agent is preferably used in an amount of usually 0.01 mol / l to 1.2 mol / l.

The pH of the developer used in the present invention is preferably in the range of 9 to 13. More preferably, the pH is in the range of 10 to 12.

Alkaline agents used for setting the pH include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate tribasic, and potassium phosphate tribasic.
Contains pH adjusters.

Buffers such as JP-A-61-28708 (borate) and JP-A-60-93439 (for example, saccharose, acetoxime, 5-sulfosalicylic acid), phosphates and carbonates may be used.

Additives used in addition to the above components include sulfites such as sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, potassium metabisulfite, sodium formaldehyde sodium bisulfite; sodium bromide, potassium bromide, iodide Development inhibitors such as potassium: organic solvents such as ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide, methyl cellosolve, hexylene glycol, ethanol and methanol: 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzimidazole-5 -Turnips such as mercapto compounds such as sodium sulfonate, indazole compounds such as 5-nitroindazole, and benztriazole compounds such as 5-methylbenztriazole May include agents, toning if necessary, surfactants, defoamers, water softeners, may contain such amino compounds described in JP-56-106244.

In the present invention, a silver stain inhibitor, for example, a compound described in JP-A-56-24347 can be used in the developer.

Amino compounds such as alkanolamines described in JP-A-56-106244 can be used in the developer used in the present invention.

LFA Meson, "Photographic Processing Chemistry", Focal Press (1966
226-229, U.S. Pat.Nos. 2,193,015 and 2,592,3
No. 64, JP-A-48-64933 and the like may be used.

The fixing solution used in the present invention is an aqueous solution containing a thiosulfate, and has a pH of 3.8 or more, preferably 4.2 to 5.5.

Examples of the fixing agent include sodium thiosulfate and ammonium thiosulfate. Thiosulfuric acid ions and ammonium ions are essential components, and ammonium thiosulfate is particularly preferable from the viewpoint of fixing speed. The amount of the fixing agent to be used can be appropriately changed and is generally about 0.1 to about 6 mol / l. The fixing solution may contain a water-soluble aluminum salt which acts as a hardening agent. Aluminum, ammonium sulfate, potassium alum and the like.

Tartaric acid, citric acid or their conductors can be used alone or in combination of two or more in the fixing solution.
It is effective that these compounds contain at least 0.005 mol per fixing solution, particularly 0.01 mol / l to 0.03 mol / l.

Specifically, there are tartaric acid, potassium tartrate, sodium tartrate, potassium sodium tartrate, citric acid, sodium citrate, potassium citrate, lithium citrate, ammonium citrate and the like.

The fixing solution may optionally contain a preservative (eg, sulfite or bisulfite), a pH buffer (eg, acetic acid or nitric acid), a pH adjuster (eg, sulfuric acid), a chelating agent having a water softening property, The compounds described in JP-A-60-213562 can be included.

[Example] An example of the present invention will be described below.

Experimental Example 1 Konica Fixer 851 (manufactured by Konica Corporation) (1) 300 cc, (2) 500 cc or (3) 700 cc as a fixing solution in 62 liters of water, assuming that the fixer component is brought into the washing water of the photosensitive material. By adding a 6% aqueous solution of hydrogen peroxide as a purifying agent to each of them to reduce the iodine consumption to 220 mg / l or less, which is the regulation standard value, with respect to the thiosulfuric acid component in the mixed fixing solution. Substitution tests were performed to determine the required cleanser addition. The results are shown in FIG. 2 for the above cases (1), (2) and (3). However, the amount of iodine consumed was adjusted to be almost neutral based on the sewage test method, and then a fixed amount of an iodine-potassium iodide solution was added to the sample, and the remaining iodine was left after standing at room temperature for 2 to 3 minutes. It was measured by titration with a 1 / 100N sodium thiosulfate solution.

From FIG. 2, in order to reduce the iodine consumption of each of the three fixer concentrations to 220 mg / l or less, it is necessary to add hydrogen peroxide in a molar ratio of about 0.9 to 1.25 with respect to ammonium thiosulfate. It turns out to be good. Similarly, the amount of hydrogen peroxide to be added can be determined for various thiosulfate ion concentrations.

Example 1 An experiment was performed under the following experimental conditions.

Automatic developing machine: Processing equipment for printing film and paper Konica Automatic Processor GR-27 Developing solution: Konica developer type 651K Fixing solution: Konica fixer type 851 Processing material: Konica clear light contact film CRH,
CRHE (Konica Corporation) Konica Clearlight Contact Film is a plate making printer P-607 (Light Source: Dainippon Screen Co., Ltd.)
Exposure with ultra-high pressure mercury lamp URT-CHM-1000), blackening rate about 50%
A paper size of 508 x 610 mm was used.

First, cut off the supply valve from the water supply to Konica Automatic Processor GR-27 (hereinafter referred to as GR-27).
l of vinyl chloride water storage tank
22 liters of rinsing water was also charged into the GR-27 rinsing tank, and a total of 62 liters of water was circulated. In this state, the aforementioned C
RH and CRHE were continuously processed. Entire processing 40 sheets, 65 sheets, 85 sheets, 1
Table 1 shows the results of calculating the pH value and the iodine consumption by sampling the washing water in the water storage tank at each of the 05, 135, 150, 200, and 270 treatment times.

In addition, the same treatment was performed, and the 6% hydrogen peroxide solution obtained from the measured values at the above-mentioned respective treatment times based on the method of Experimental Example 1 was added to the water storage tank from the purifier supply tank having a total capacity of 11, and then the water was stored again. Table 1 shows the results of sampling the washing water in the tank and measuring the pH value and iodine consumption in the same manner.

As is clear from Table 1, by adding 6% hydrogen peroxide solution corresponding to the measured value of iodine consumption at each treatment point to the washing water, it is possible to purify the contaminated washing water to a water quality that can be discharged to sewage. Becomes

[Effects of the Invention] As described above in detail, by circulating and using the washing water according to the present invention, the water saving efficiency is greatly improved.

Further, according to the present invention, it is possible to provide an automatic developing apparatus which is compact, has improved maintenance and cost, and has excellent water saving efficiency.

Further, the automatic developing device of the present invention can improve the water-saving efficiency and purify the used washing water, which is to be a waste liquid having a high pollution load, to a level at which sewage can be drained, thereby reducing the burden on the user for waste liquid treatment. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing an example of a water washing section of the automatic developing apparatus of the present invention, and FIG. 2 is a diagram showing an iodine consumption amount and an amount of hydrogen peroxide added to ammonium thiosulfate in a substitute experiment of Experimental Example 1. 6 is a graph showing the relationship of. DESCRIPTION OF SYMBOLS 1 ... Rinse tank, 2 ... Water storage tank 3 ... Circulation means 4 ... Purifier supply tank, 5 ... Discharge means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshisuke Kobayashi 1 Konica Co., Ltd., Sakura-cho, Hino-shi, Tokyo (56) References JP-A-50-145140 (JP, A) JP-A-54-119762 (JP, A) JP-A-63-291679 (JP, A) JP-A-55-7793 (JP, A)

Claims (5)

(57) [Claims] 1. An automatic developing apparatus for a silver halide black-and-white photosensitive material comprising at least a developing section, a fixing section and a rinsing section, wherein the rinsing section comprises: a rinsing means for rinsing the photographic material; Water storing means for temporarily storing water containing the used used washing water as washing water supplied to the washing means; washing water in the washing means and washing water in the water storing means; A circulating means for circulating between the circulating means, a contaminant concentration means for supplying a purifying agent to the water storage means when the contamination concentration of the washing water circulated by the circulating means exceeds a predetermined value; and Draining means for draining at least a part of the washing water in the water storage means. The automatic developing apparatus for a silver halide black-and-white photosensitive material, characterized in that: 2. An automatic developing apparatus for a silver halide black-and-white photosensitive material comprising at least a developing section, a fixing section and a washing section, wherein said washing section comprises: washing means for washing said photosensitive material with water; A water storage means for temporarily storing water containing the used washing water as washing water supplied to the washing means; a washing water in the washing means and a washing water in the water storing means; A circulating means for circulating between, a contaminant concentration measuring means for measuring a contaminant concentration of the washing water circulated by the circulating means, and a contaminant concentration measured by the contaminant concentration measuring means exceeding a predetermined value, The black-and-white silver halide described above, comprising: a purifier supply means for supplying a purifier to the water storage means; and a drain means for draining at least a part of the washing water in the water storage means after supplying the purifier. Automatic developing device for photosensitive materials. 3. The automatic developing apparatus according to claim 1, wherein the purifying agent is an oxidizing agent. 4. The automatic developing apparatus according to claim 1, wherein the purifying agent is hydrogen peroxide. (5) Claim (1), (2), (3) or (4)
When processing a silver halide black-and-white photosensitive material using the automatic developing apparatus described above, when the contamination concentration of the circulating washing water exceeds a predetermined value, a purifying agent is supplied from the purifying agent supply unit to the water storage unit. A method for treating waste water, comprising: purifying washing water in a water storage means, and then draining at least a part of the washing water in the water storage means by a drain means.