JP3234837B2 - How to process photographic wastewater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying photographic processing waste liquid. More specifically, the present invention relates to a processing method for purifying a photographic processing waste liquid having a high chemical oxygen demand (hereinafter also referred to as COD) and containing compounds such as silver, iron, aluminum, phosphorus, halogen, and nitrogen. is there.

[0002]

2. Description of the Related Art Conventionally, a purification method effective for reducing COD of a photographic processing waste liquid, a purification method for removing nitrogen, phosphorus, and the like contained in the waste liquid, a purification method for removing heavy metals contained in the waste liquid, and those methods have been known. Various purification treatment methods such as a combined purification method are being studied. For example, biological treatment, combustion, drying by heating and evaporating, oxidation with chlorine-based chemicals, electrolytic oxidation, hydrogen peroxide-ferrous salt method, ozone oxidation, aggregation by addition of inorganic or organic flocculants Separation and removal methods, adsorption separation and removal methods using activated carbon, inorganic adsorbents or organic polymer materials, reverse osmosis methods using membranes, electrodialysis methods and ultrafiltration methods have been implemented or proposed.

[0003]

When the above-mentioned methods are used, there are many problems as described below, and there is a need for improvement in each method. For example, (1)
Biological treatment method, coagulation separation removal method, adsorption separation removal method, electrofiltration method, reverse osmosis membrane method, ultrafiltration method, hydrogen peroxide-ferrous salt method, ozone oxidation method, etc. It is difficult to perform purification treatment to a sufficient level. (2) Combustion method, drying method, electrolytic oxidation method, ozone oxidation method, adsorption separation removal method, reverse osmosis membrane method, electrofiltration method, ultra Filtration and other methods have high processing costs, and (3) combustion, drying, coagulation and separation methods, and adsorption separation and removal methods have the problem of producing substances that cause secondary pollution after processing. is there.

[0004] The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a method for purifying a photographic processing waste liquid which is capable of removing COD, nitrogen, phosphorus, heavy metals and the like to a sufficiently low level from a photographic processing waste liquid at a low cost without generating a substance which causes secondary pollution, and which is easy to maintain. Is to provide.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a photographic processing waste liquid at a temperature of 140 ° C. or more and less than 370 ° C. while supplying a gas containing oxygen, and the waste liquid maintains a liquid phase. The catalyst is subjected to a non-catalyst wet oxidation treatment under a pressure of, then, separated and removed solids and suspensions formed, and then supplied with an oxygen-containing gas at a temperature of 140 ° C. or higher and lower than 370 ° C. The present invention provides a method for treating a photographic processing waste liquid, wherein a catalytic wet oxidation treatment is performed under a pressure for maintaining the photographic processing waste liquid.

[0006]

According to the present invention, in processing photographic processing waste liquid, the photographic processing waste liquid is supplied under supply of a gas containing oxygen.
A first step of performing non-catalytic wet oxidation treatment at a temperature of 140 ° C. or more and less than 370 ° C. and a pressure at which the waste liquid maintains a liquid phase is employed. By this first step, substances harmful to catalytic wet oxidation treatment such as aluminum, phosphorus, silicon, calcium and magnesium (hereinafter also referred to as harmful substances) or heavy metals such as silver and iron in photographic processing waste liquid Turns into water-insoluble or hardly-soluble substances such as oxides, hydroxides, inorganic salts, and other compounds to form precipitates. In addition, silver or the like contained in a trace amount becomes a compound that is insoluble or hardly soluble in water by this treatment, and is adsorbed by an iron compound or the like contained in the photographic processing waste liquid that precipitates out to form a precipitate. By removing the precipitate or suspension of the liquid at the outlet of the first step by solid-liquid separation from the liquid (second step), it becomes possible to remove harmful substances and heavy metals. That is, in the present invention, the second step outlet liquid is supplied at a temperature of 140 ° C. or more and 370 ° C. under supply of a gas containing oxygen.
The third step of performing the catalytic wet oxidation treatment at a temperature of less than and at a pressure at which the waste liquid retains a liquid phase is employed. By employing the first step and the second step, the catalyst used in the third step can be used. The cause of the blockage of the wet oxidation reactor and the deterioration of the catalyst due to the adsorption of heavy metals and the formation of scale are excluded.

Due to the above effects, the amount of iron contained in the photographic processing waste liquid is small, the amount of heavy metals and harmful substances to be removed is large, or the amount of heavy metals and harmful substances to be removed for other reasons is large. If the concentration is not reduced to a sufficient level even after solid-liquid separation and removal after the non-catalytic wet oxidation treatment (first step), add an iron compound etc. which is dissolved in the photographic processing waste liquid before the non-catalytic wet oxidation treatment And
Increasing the iron concentration is also a preferred method. The iron compound is not particularly limited as long as it can be dissolved in the photographic processing waste liquid, and examples thereof include ferrous sulfate, ferric sulfate, ferrous nitrate, ferrous chloride, and an iron-EDTA complex. be able to.

[0008] In addition, there have been cases where the concentration of heavy metals or harmful substances to be removed is not reduced to a sufficient concentration after solid-liquid separation after the non-catalytic wet oxidation treatment (first step). It can be further removed using a method for purifying heavy metals or harmful substances, for example, an adsorption separation method using activated carbon, an inorganic adsorbent or an organic polymer material, and an electrodialysis method.

[0009] Further, the processing is simultaneously performed with other contaminants such as organic and inorganic CO in the photographic processing wastewater.
It also oxidizes and oxidatively decomposes the D component and converts it into lower molecular weight organic substances, inorganic salts, carbon dioxide gas, nitrogen gas, water, ash, etc., and can partially purify the COD of the photographic processing waste liquid.

If the first step of the present invention is adopted, when heavy metals and harmful substances form compounds with organic substances and the like in the photographic processing waste liquid and are dissolved in the photographic processing waste liquid, the photograph Since organic substances in the processing waste liquid can be simultaneously decomposed, it is particularly effective for removing heavy metals and harmful substances from the photographic processing waste liquid. That is, when heavy metals and harmful substances are dissolved in the photographic processing waste liquid, for example, as a chelate complex or the like, the chelating agent is decomposed by this treatment, and the heavy metals and harmful substances are released as ions. You. For this reason, heavy metals, harmful substances, and the like become insoluble or poorly soluble compounds in water, and are easily precipitated and easily removed.

Further, the precipitate after solid-liquid separation and removal has an extremely small amount of organic matter, especially high-molecular organic matter, as compared with the coagulation separation method and the adsorption separation method. It is also easy to treat the precipitate later.

The photographic processing waste liquid purified by the processing method of the present invention can be directly discharged or subjected to biological treatment or chemical treatment as post-treatment. Even in this case,
Heavy metals and harmful substances are removed from the wastewater of photographic processing in advance, and COD components and the like are considerably reduced. Furthermore, remaining COD components and the like are decomposed into substances which are very easily decomposed in biological processing and chemical processing. Therefore, the burden on the biological treatment equipment or the chemical treatment equipment becomes very small.

[0013] Further, the present invention requires less land and has a compact apparatus. Therefore, compared with the case where a conventional wastewater treatment facility such as a biological treatment facility or a combustion treatment facility is employed, the treatment facility is reduced. And the processing process is simplified, which is advantageous in terms of capital investment and running costs.

The concentration of COD in the photographic processing waste liquid is 1 g /
It is effective when the amount is contained in the range of 5 g / liter to 200 g / liter.
150 g / l. COD concentration 200g /
When it exceeds 1 liter, the heat of oxidation of COD becomes extremely large, so that it is difficult to control the processing apparatus. When the amount is less than 1 g / liter, there is little effect of treating the photographic processing waste liquid by using the processing method of the present invention, and the processing can be performed by using other conventional techniques. When it is less than 5.0 g / liter, the heat of oxidation of COD is small. In such a case, even if heat is recovered using a heat exchange device as an accessory equipment, the self-sustaining operation of the wet oxidation treatment device by this heat can be performed. It will be difficult. In such a case, there is no hindrance to the wet oxidation itself, but a separate heat supply device is required when performing the treatment, which is relatively disadvantageous in terms of energy consumption.

As the non-catalytic wet oxidation treatment apparatus and the catalytic wet oxidation treatment apparatus used in the present invention, those which are usually used are used, and the wet oxidation reaction tower may be either a single tube type or a multi-tube type. You may.

The non-catalytic wet oxidation treatment described herein is as follows.
The wet oxidation treatment is not particularly limited by filling the inside of the wet oxidation reaction reaction tower with the catalyst described below, but is not particularly limited. Generally, treatment using an empty wet oxidation reaction tower is shown. In addition, a filler made of metal, ceramic, or the like may be filled in the wet oxidation reaction tower to improve the agitation of liquid and gas.

The catalyst described here may be any catalyst as long as it is a solid catalyst and has both activity and durability under the conditions of liquid phase oxidation. A catalyst containing iron, aluminum, silicon, zirconium, activated carbon, or the like can be mentioned, and it is preferable to use an oxide such as titanium, titanium-zirconium, or titanium-iron. These catalysts may contain a second component in addition to the above components (hereinafter, referred to as a first component).

As the second component, at least one kind of metal such as manganese, cobalt, nickel, tungsten, copper, cerium, silver, platinum, palladium, rhodium, gold, iridium, ruthenium, or a component comprising these metal compounds is used. Can be used. This catalyst is the first
The second component 25 to 25 to 99.95% by weight of the component
The proportion is preferably 0.05% by weight. In addition, various shapes can be adopted as the shape of the catalyst, and the shape is not particularly limited.

In the treatment method of the present invention, the treatment liquid after the non-catalytic wet oxidation treatment is subjected to solid-liquid separation and removal, and then the catalytic wet oxidation treatment is performed. At this time, in the catalyst wet oxidation treatment, an adsorption tower filled with an inorganic adsorbent is provided in front of the catalyst wet oxidation reaction tower,
Further, poisoning of the catalyst by heavy metals or harmful substances that have not been sufficiently removed can be appropriately prevented. The inorganic adsorbent is not particularly limited, but is preferably an oxide containing titanium such as titanium, titanium-zirconium, and titanium-iron.

The treatment pressure of the non-catalytic wet oxidation treatment or the treatment pressure of the catalytic wet oxidation treatment of the present invention is appropriately selected depending on the correlation with each treatment temperature, and is determined by the pressure at which the liquid maintains a liquid phase.

The treatment temperature of the non-catalytic wet oxidation treatment or the treatment temperature of the catalytic wet oxidation treatment of the present invention is 140.degree.
The temperature is lower than 0 ° C, and preferably 180 ° C or higher and lower than 300 ° C. Above 370 ° C., the liquid cannot maintain the liquid phase.
When the temperature is lower than 140 ° C., the processing efficiency is reduced.

The processing amount of the photographic processing waste liquid in the non-catalytic wet oxidation processing can be increased when the processing temperature is high, and reduced when the processing temperature is low. For example, when the processing temperature is 270 ° C., the space velocity is 0.5 h
r ^{-1 to 5} hr ^-1 is preferred. Further, when the processing temperature is 180 ° C., it is preferably 0.1 hr ^{−1 to 1} hr ⁻¹ . At a space velocity of 5 hr ^-1 at 270 ° C. and at a space velocity of 1 at 180 ° C.
If it exceeds hr ^-1 , the processing efficiency decreases, and conversely 270
When the space velocity at 0.5 ° C. is less than 0.5 hr ⁻¹ and when the space velocity at 180 ° C. is less than 0.1 hr ⁻¹ , the processing amount of the photographic processing waste liquid decreases, the equipment becomes excessively large, and appropriate It is not preferable because it exceeds the range of efficiency.

Therefore, the higher the processing temperature, the higher the processing efficiency and the higher the processing speed, and the smaller the reactor. However, the higher the processing pressure, the more difficult the maintenance and the like, and the COD of the wastewater. When the concentration is low, it becomes difficult to maintain the temperature in an independent operation. Conversely, when the processing temperature is low, the processing efficiency is degraded, but the processing pressure is reduced, so that maintenance and the like become easier. In addition, if the treatment efficiency of the COD component is excessively increased in the non-catalytic wet oxidation treatment more than necessary, a heat source for maintaining the temperature in the subsequent catalyst wet oxidation treatment and performing self-sustaining operation becomes insufficient. For this reason, in the non-catalytic wet oxidation treatment, the solid matter and the suspension generated by the wet oxidation treatment are sufficiently precipitated, and the COD treatment efficiency is such that they can be sufficiently separated and removed after the non-catalytic wet oxidation treatment. It is preferable to suppress it. The treatment efficiency of the COD component in the non-catalytic wet oxidation treatment is not particularly limited, and may be appropriately selected depending on the case, but is generally 20% to 80%. From the above, the processing temperature, the processing pressure, and the processing space velocity are appropriately selected from the above ranges depending on the case.

In the catalytic wet oxidation treatment, after the non-catalytic wet oxidation treatment, the treatment amount of the treatment liquid separated into solid and liquid can be increased when the treatment temperature is high as in the non-catalytic wet oxidation treatment. When the processing temperature is low, the number is small. Generally, the space velocity is 0.1 hr ^{-1 to 5} hr
^-1 , more preferably 0.5 hr ^{-1 to 3} hr ^-1 . When the space velocity exceeds 5 hr ^-1 , the processing efficiency decreases, and when the space velocity is less than 0.1 hr ^-1 ,
This is because the throughput is reduced and the equipment becomes excessive.

In the present invention, the oxygen-containing gas means a gas containing oxygen or ozone. When a gas such as ozone or oxygen is used, it can be appropriately diluted with an inert gas or the like before use. Preferably air is used,
In addition to these gases, oxygen-containing waste gas generated from other plants can be used as appropriate.

In the case of non-catalytic wet oxidation treatment, the amount of this gas can be appropriately selected depending on the concentration of the photographic processing waste liquid. In this case, 0.5 to 5 times, more preferably 1.0 to 3 times the amount of oxygen necessary to completely convert the COD component of the photographic processing waste liquid into water, carbon dioxide, inorganic salts, and other ash.
It is twice. If it exceeds 5 times, unnecessary oxygen is supplied. If it is less than 0.5 times, the required amount of oxygen is insufficient, and the purification of the photographic processing waste liquid is incomplete. Further, the range of 0.5 to 1.0 times is not sufficient as the amount of oxygen necessary to completely convert the COD component of the photographic processing waste liquid into water, carbon dioxide, inorganic salts, other ash, etc. In order to secure COD in a certain catalytic wet oxidation process, this COD
This is one of the effective means when it is desired to keep the processing efficiency low.

Similarly, in the case of the catalytic wet oxidation treatment, the amount of oxygen required to completely convert the COD component of the treatment liquid, which has been further separated into solid and liquid after the non-catalytic wet oxidation treatment, into water, carbon dioxide, inorganic salts, and other ash components. 0.5 to 3 times, more preferably,
It is 1.0 times to 2 times. If the amount exceeds three times, unnecessary oxygen is supplied. If the amount is less than 0.5 times, the required amount of oxygen is insufficient, and the photographic processing waste liquid is incompletely purified. When the oxygen supply amount is in the range of 0.5 to 1.0 times, the COD component of the photographic processing waste liquid is insufficient as the amount of oxygen necessary for completely converting water, carbon dioxide, inorganic salts, other ash, and the like. However, the oxygen supply in this range is usually C
Since the treatment efficiency of OD is less than 100%, the supplied oxygen is often not used 100% and remains,
In such a case, even if the supplied oxygen amount is reduced to less than 1.0 times in accordance with the actual processing efficiency, the COD processing efficiency does not change much, so that it can be adopted.

In the processing method of the present invention, the photographic processing waste liquid is subjected to a non-catalytic wet oxidation treatment, and then a solid-liquid separation processing device is used to separate and remove insolubles and the like generated by the non-catalytic wet oxidation treatment. This removal operation may be carried out continuously under solid-liquid separation and removal operations under pressurized conditions, or the solid-liquid separation operation may be performed under depressurized and normal pressure conditions. Absent. Further, as the solid-liquid separation treatment device, various devices such as a sedimentation treatment device, a centrifugal separation treatment device, and a filtration separation treatment device can be adopted. At this time, it is preferable to add a flocculant and a flocculant, if necessary, to increase the processing speed and the separation efficiency. Various conventional coagulants and coagulants can be used, and are not particularly limited. However, it is preferable to use an organic polymer coagulant as the coagulant. The water-soluble inorganic coagulant may cause catalyst poisoning in the next catalytic wet oxidation treatment, and its use is often limited. As the coagulant, various conventional coagulants can be used similarly to the coagulant, and are not particularly limited. However, organic coagulants and water-insoluble inorganic coagulants are used. It is preferable to use an aggregation aid.
The water-soluble inorganic coagulant may cause catalyst poisoning in the next catalytic wet oxidation treatment, and its use is often limited.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0030]

EXAMPLE 1 A non-catalytic wet oxidation treatment and a solid-liquid separation treatment were carried out continuously for 500 hours using the non-catalytic wet oxidation treatment device and the solid-liquid separation treatment device shown in FIG. Using the treatment liquid obtained after 500 hours, the amounts of iron, silver, aluminum, phosphorus and silicon in the filtrate were measured by inductively coupled high frequency plasma emission spectroscopy to determine the concentration. Similarly, TOC, COD (Cr) and total nitrogen were measured to determine the concentration and the processing efficiency.

The detailed usage of this processing apparatus is as follows. The photographic processing waste liquid sent from the waste liquid supply line 8 is supplied to the waste liquid supply pump 3 at a flow rate of 2 liter / hr at 90 kg / cm ² G.
Until the pressure was increased. On the other hand, after the pressure of the air supplied from the oxygen-containing gas supply line 9 is increased by the compressor 5, the ratio of O ₂ / COD (Cr) (the amount of oxygen in the air / the required amount of chemical oxygen) is equal to 2.0. It was mixed into the processing waste liquid. This gas-liquid mixture is heated in the heat exchanger 2 via the gas-liquid mixture supply line 10 and then introduced into the non-catalytic wet oxidation reaction tower 1 (empty tower) from below, and subjected to a non-catalytic wet oxidation treatment at a processing temperature of 260 ° C. Then, the water to be treated was cooled in the heat exchanger 2 through the treated water line 11, and was flown to the gas-liquid separator 4. The space velocity of this photographic processing waste liquid was 2.0 hr ^-1 . In the gas-liquid separator 4, the liquid level controller (L
C), the liquid level is detected, the liquid level control valve 6 is operated to maintain a constant liquid level, and the pressure controller (P
According to C), the pressure is detected and the pressure control valve 7 is operated to maintain a constant pressure. And
The treated water discharged from the treated water discharge line 13 has been subjected to a solid-liquid separation treatment by a solid-liquid separation treatment device 14. The properties of the photographic processing waste liquid subjected to the processing were as follows: iron: 830 mg / liter, silver: 11 mg / liter, aluminum: 90 mg / liter.
/ Liter, phosphorus 35mg / liter and silicon 5m
g / liter. The TOC was 13.5 g / liter, COD (Cr) was 52.0 g / liter, and the total nitrogen concentration was 2.7 g / liter.

The results obtained are as follows: iron 1 mg / l or less, silver 1 mg / l or less, aluminum 1 mg / l or less, phosphorus 3 mg / l and silicon 2 mg / l.
/ Liter. Further, the TOC concentration was 5.9 g / l, the COD (Cr) concentration was 21.5 g / l, and the total nitrogen concentration was 2.6 g / l.
6%, COD (Cr) treatment efficiency 59%, Total nitrogen treatment efficiency 0
%Met.

Subsequently, 1 liter of the catalyst was charged into the catalyst wet oxidation reaction tower 15 using the solid-liquid separation liquid and the catalyst wet oxidation treatment apparatus shown in FIG. An oxidation treatment was performed. Then, using the treatment liquid obtained after 500 hours, the amounts of iron, silver, aluminum, phosphorus and silicon in the treatment liquid were measured by inductively coupled high frequency plasma emission spectroscopy to determine the concentrations. Similarly, TOC, COD (Cr) and total nitrogen were measured to determine the concentration and the processing efficiency. The catalyst used was a catalyst composed of titanium-zirconium composite oxide and platinum (0.4% by weight of platinum).

The detailed usage of this processing apparatus is as follows. The solid-liquid separated liquid sent from the waste liquid supply line 22 is supplied to the waste liquid supply pump 17 at a flow rate of 1 liter / hr at 80 kg / hr.
The pressure was increased to cm ² G. On the other hand, the air supplied from the oxygen-containing gas supply line 23 is supplied to the compressor 19.
O ₂ / COD (Cr) (oxygen amount in air /
(Chemical oxygen demand) = 1.05. After heating the gas-liquid mixture in the heat exchanger 16 via the gas-liquid mixture supply line 24, the mixture is introduced into the catalyst wet oxidation reaction tower 15 filled with the catalyst from below, and subjected to the catalyst wet oxidation treatment at a treatment temperature of 260 ° C. The water to be treated was cooled in the heat exchanger 16 via the treated water line 25, and was flown to the gas-liquid separator 18. The space velocity of this solid-liquid separation liquid is 1.0 h
r ^-1 . In the gas-liquid separator 18, a liquid level is detected by a liquid level controller (LC), a liquid level control valve 20 is operated to maintain a constant liquid level, and a pressure is detected by a pressure controller (PC). Pressure control valve 21
Is operated to maintain a constant pressure.

The results obtained are as follows: iron 1 mg / l or less, silver 1 mg / l or less, aluminum 1 mg / l or less, phosphorus 2 mg / l and silicon 1 mg / l.
/ Liter. The TOC concentration was 0.77 g / l, the COD (Cr) concentration was 2.4 g / l, and the total nitrogen concentration was 0.15 g / l. The TOC treatment efficiency was 87%, the COD (Cr) treatment efficiency was 89%, and the total nitrogen treatment was respectively. The efficiency was 94%.

Accordingly, the processing efficiencies of TOC, COD (Cr) and total nitrogen calculated from the first photographic processing waste liquid in this embodiment are 94%, 95% and 95%, respectively.
Becomes

Example 2 Using the non-catalytic wet oxidation treatment apparatus and the solid-liquid separation treatment apparatus shown in FIG. 1, the same operation as in Example 1 was carried out for 1000 hours continuously under the following conditions. Solid-liquid separation treatment was performed, and the treatment liquid after 1000 hours was analyzed.

The conditions of the non-catalytic wet oxidation treatment are as follows: the flow rate of the photographic processing waste liquid is 0.5 liter / hr, the space velocity of the photographic processing waste liquid is 0.5 hr ^-1 , O ₂ / COD (Cr) (the amount of oxygen in air /
Chemical oxygen demand) = 1.0, processing pressure 50 kg / cm
² G, treatment temperature 200 ° C. The properties of the photographic processing waste liquid subjected to the processing were as follows: iron 510 mg / liter, silver 2
5 mg / l, aluminum 65 mg / l and calcium 2 mg / l. Also TOC
Was 7.4 g / L, COD (Cr) was 35.0 g / L, and the total nitrogen concentration was 9.5 g / L.

The results were as follows: iron 1 mg / liter or less, silver 1 mg / liter or less, aluminum 2 mg / liter and calcium 1 mg / liter or less. In addition, the TOC concentration is 5.6 g / liter, and the COD (C
r) concentration 22.8 g / l, total nitrogen concentration 9.2 g /
In liters, TOC treatment efficiency 24%, COD
(Cr) The treatment efficiency was 35%, and the total nitrogen treatment efficiency was 0%.

Subsequently, using the solid-liquid separation liquid, the catalytic wet oxidation treatment was carried out continuously for 250 hours by the same operation as in Example 1 using the catalytic wet oxidation treatment apparatus shown in FIG. 2 under the following conditions. After 250 hours, the processing solution was analyzed. The catalyst was the same catalyst as in Example 1 comprising titanium-zirconium composite oxide and platinum (0.4% by weight of platinum).
1 liter was used.

The conditions for the catalytic wet oxidation treatment were as follows: the flow rate of the solid-liquid separation liquid was 2.0 liter / hr, and the space velocity of the solid-liquid separation liquid was 2.0 liter / hr.
hr ⁻¹ , O ₂ / COD (Cr) (oxygen amount in air / chemical oxygen demand) = 1.0, processing pressure 75 kg / cm ² G,
The processing temperature was 250 ° C.

The results obtained were 1 mg / l or less for iron, 1 mg / l or less for silver, 1 mg / l or less for aluminum and 1 mg / l for calcium. In addition, the TOC concentration was 0.39 g / liter, and the COD
(Cr) concentration 2.3g / l, total nitrogen concentration 0.50g
/ Liter, TOC treatment efficiency 93%, COD
(Cr) The treatment efficiency was 90%, and the total nitrogen treatment efficiency was 95%.

Accordingly, the processing efficiencies of TOC, COD (Cr) and total nitrogen calculated from the first photographic processing waste liquid in this embodiment are 95%, 93% and 95%, respectively.
Becomes

Example 3 Using the non-catalytic wet oxidation treatment apparatus and the solid-liquid separation treatment apparatus shown in FIG. 1, the same operation as in Example 1 was carried out for 500 hours continuously under the following conditions. A solid-liquid separation treatment was performed, and the treatment liquid was analyzed after 500 hours.

The conditions of the non-catalytic wet oxidation treatment were as follows: the flow rate of the photographic processing waste liquid was 1.0 liter / hr, the space velocity of the photographic processing waste liquid was 1.0 hr ^-1 , O ₂ / COD (Cr) (the amount of oxygen in air /
Chemical oxygen demand) = 2.5, processing pressure 90 kg / cm
² G, was treated temperature 250 ° C.. Further, the properties of the photographic processing waste liquid subjected to the processing were as follows: iron 940 mg / liter, silver 1
5 mg / l, aluminum 260 mg / l, phosphorus 115 mg / l, calcium 5 mg / l and magnesium 3 mg / l.
TOC is 36.0 g / liter, COD (Cr) 13
The concentration was 0 g / liter and the total nitrogen concentration was 8.9 g / liter.

The results obtained were as follows: iron 1 mg / l or less, silver 1 mg / l or less, aluminum 4 mg / l, phosphorus 15 mg / l, calcium 3 mg / l
Liter and magnesium 2 mg / liter. In addition, TOC concentration 10.1 g / liter, COD
(Cr) concentration 34.0 g / liter, total nitrogen concentration 8.0 g
/ L, TOC treatment efficiency 72%, COD
(Cr) The treatment efficiency was 74%, and the total nitrogen treatment efficiency was 0%.

Subsequently, using the above-mentioned solid-liquid separation liquid, FIG.
The catalyst wet oxidation treatment was carried out continuously for 500 hours by the same operation as in Example 1 using the catalyst wet oxidation treatment device attached to the adsorption tower shown in (1) under the following conditions. After 500 hours, the processing solution was analyzed. The catalyst is titanium-
One liter of a catalyst composed of a composite oxide of iron and ruthenium (1.5% by weight of ruthenium) was used, and one liter of titania was used as an adsorbent.

The conditions of the catalytic wet oxidation treatment are as follows: the flow rate of the solid-liquid separation liquid is 0.5 liter / hr, and the space velocity of the solid-liquid separation liquid is 0.5
hr ⁻¹ , O ₂ / COD (Cr) (oxygen amount in air / chemical oxygen demand) = 1.1, processing pressure 50 kg / cm ² G,
The processing temperature was 200 ° C.

The results obtained are as follows: iron 1 mg / l or less, silver 1 mg / l or less, aluminum 1 mg / l or less, phosphorus 2 mg / l, calcium 1 mg / l
/ L and less than 1 mg / l magnesium. In addition, TOC concentration 2.22 g / liter,
COD (Cr) concentration 6.1 g / liter, total nitrogen concentration 0.
92g / liter, TOC treatment efficiency 78%,
The COD (Cr) treatment efficiency was 82%, and the total nitrogen treatment efficiency was 89%.

Therefore, the processing efficiencies of TOC, COD (Cr) and total nitrogen calculated from the first photographic processing waste liquid in this embodiment are 94%, 95% and 90%, respectively.
Becomes

COMPARATIVE EXAMPLE 1 The catalyst-free wet oxidation treatment and the solid-liquid separation treatment were not performed.
The photographic processing waste liquid used in Example 1 was directly treated using the catalytic wet oxidation treatment apparatus shown in (1). The processing conditions are O ₂
/ COD (Cr) (oxygen amount in air / chemical oxygen demand)
The conditions were the same as those of the catalytic wet oxidation treatment described in Example 1, except that 2.0 was used.

As a result, after about 400 hours, the catalytic wet oxidation reaction tower was closed, and the treatment could not be performed.

COMPARATIVE EXAMPLE 2 In Example 3, a wet oxidation reactor shown in FIG. 3 was used, and in Example 3, a column used as an adsorption tower was used as a non-catalytic wet oxidation reaction tower (empty tower). It was used in a wet oxidation apparatus, and continuous processing was performed without performing the solid-liquid separation processing that must be performed in the present invention. The photographic processing waste liquid used in the processing was the photographic processing waste liquid used in Example 1, and the photographic processing waste liquid was used under the following conditions.

The common conditions for the non-catalytic and catalytic wet oxidation treatments are that the flow rate of the photographic processing waste liquid is 1.0 liter / hr, O ₂ /
COD (Cr) (oxygen content in air / chemical oxygen demand) =
2.0, processing pressure 80 kg / cm ² G, processing temperature 260
° C. The space velocity of the photographic processing waste liquid in the noncatalytic wet oxidation was 1.0 hr ^-1 , and the space velocity of the noncatalytic wet oxidation processing liquid in the catalytic wet oxidation was 1.0 hr ^-1 . The catalyst used was the same catalyst as in Example 1 consisting of titanium-zirconium composite oxide and platinum (platinum 0.4% by weight).
Liters were used.

As a result, after about 450 hours, the catalytic wet oxidation reaction tower was closed, and the treatment could not be performed.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a processing apparatus according to the present invention.

[Explanation of symbols]

 1. 1. Non-catalytic wet oxidation reaction tower Heat exchanger 3. Waste liquid supply pump 4. Gas-liquid separator 5. Compressor 6. Liquid level control valve 7. Pressure control valve 8. Waste liquid supply line 9. Oxygen-containing gas supply line 10. 10. Gas-liquid mixture supply line Treated water line 12. Gas discharge line 13. 13. Treated water discharge line Solid-liquid separation processing equipment

FIG. 2 is an embodiment of a processing apparatus according to the present invention.

[Explanation of symbols]

 15. 15. Catalytic wet oxidation reaction tower Heat exchanger 17. Waste liquid supply pump 18. Gas-liquid separator 19. Compressor 20. Liquid level control valve 21. Pressure control valve 22. Waste liquid supply line 23. Oxygen-containing gas supply line 24. Gas-liquid mixture supply line 25. Treated water line 26. Gas discharge line 27. Treated water discharge line

FIG. 3 is an embodiment of a processing apparatus according to the present invention.

[Explanation of symbols]

 28. Catalytic wet oxidation reaction tower 29. Heat exchanger 30. Waste liquid supply pump 31. Gas-liquid separator 32. Compressor 33. Liquid level control valve 34. Pressure control valve 35. Waste liquid supply line 36. Oxygen-containing gas supply line 37. Gas-liquid mixture supply line 38. Treated water line 39. Gas discharge line 40. Treated water discharge line 41. Adsorption tower (or non-catalytic wet oxidation reaction tower)

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Koichi Nakano (56) References JP-A-5-23696 (JP, A) JP-A-5-115888 (JP, A) JP-A-5-119440 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) G03C 5/00 C02F 1/74

Claims (1)

(57) [Claims] 1. A non-catalytic wet oxidation treatment of a photographic processing waste liquid under a supply of oxygen-containing gas at a temperature of 140 ° C. or more and less than 370 ° C. and a pressure at which the waste liquid retains a liquid phase. After separating and removing the substances and suspensions, performing a catalytic wet oxidation treatment under a supply of oxygen-containing gas at a temperature of 140 ° C. or more and less than 370 ° C. and a pressure at which the waste liquid maintains a liquid phase. Of photographic processing wastewater.