JP2005169304A - Method of treating high concentration colored organic waste water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economical waste water treatment method by which high concentration colored organic waste water containing at least one of dye and pigment is cleaned and decolored to be discharged to public water or to be recycled as recycled waste water while dispensing with the liquid waste processing commission to a waste-disposal vendor to reduce the quantity of the waste processing commission. <P>SOLUTION: The method of treating the high concentration colored organic waste water containing at least one of the dye or the pigment has a process for carrying out biological treatment of the organic waste water and a process for decoloring the biologically treated water by adding ozone and an apparatus used for the same is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  Industrial wastewater, especially ink cartridges used in inkjet printers for outputting data from personal computers, digital cameras, etc. and ink waste liquid generated at ink manufacturing plants, etc. The present invention relates to a method for purifying and decolorizing high-concentration organic wastewater until it is released into public water areas such as rivers, and then treating the wastewater.

  In addition to dyes or pigments, the ink contains glycerin, glycol, polyhydric alcohol, and the like at a high concentration, and a high-concentration organic waste liquid that is colored black is discharged at an ink manufacturing plant. Initially, such ink waste liquids were collected as industrial wastes in a liquid state by a waste disposal specialist and were commissioned for incineration. In recent years, processing costs have risen due to stricter regulations on environment-related laws and waste-related laws and regulations, and therefore methods have been devised to reduce the amount of commissioned processing such as ink waste liquid. For example, a method of concentrating ink waste liquid or the like by a reverse osmosis membrane method or an evaporation concentration method.

  In the evaporative concentration method, there are JP-A-4-313302 (Patent Document 1) and JP-A-4-330903 (Patent Document 2) which are treated with ethylene glycol, and those which are treated with an alcohol-based detergent. There is an example in Japanese Patent Laid-Open No. 06-198101.

  In the method of concentrating with a reverse osmosis membrane, JP 2003-155656 A (Patent Document 4) discloses a method of separating and concentrating a dye from waste water containing the dye.

  However, in the method of concentrating the ink waste liquid by the reverse osmosis membrane method or the evaporation concentration method, the disposal of the liquid industrial waste is not completely eliminated. In the reverse osmosis membrane method, the concentrated liquid is about 1/3 of the ink waste liquid. However, the concentrated liquid of about 1/20 is also discharged as liquid waste by the evaporation concentration method. Further, the reverse osmosis membrane method requires a large cost due to periodic replacement of the reverse osmosis membrane module, and the evaporative concentrating method requires a cost of using heat energy such as steam, so that the cost reduction effect is small.

In addition, in the method of concentrating with a reverse osmosis membrane, permeated water and distilled water are generated from the concentration distillation apparatus, and the permeated water or distilled water is hardly colored, but alcohols are almost independent and contain a high concentration. Organic wastewater that cannot be discharged directly into rivers and other public waters. This permeated water and distilled water are difficult to biologically treat, and it is necessary to take measures such as mixing with other waste water and performing biological treatment with low load or discharging it to public sewers with terminal treatment plants. This means that an ink waste liquid production factory can be located only in an area where a large-scale biological treatment facility can be installed or can be accepted by public sewerage, and as a result, it may not lead to cost reduction.
Japanese Unexamined Patent Publication No. 4-313302 Japanese Unexamined Patent Publication No. 4-330903 JP 06-198101 A JP 2003-155656 A

  In view of the above situation, in the present invention, for high-concentration organic wastewater that contains at least one of a dye and a pigment and is colored, the amount of waste disposal commissioned by eliminating the disposal of liquid waste to a waste disposal specialist It is an object to provide an economical wastewater treatment method that purifies and decolors until it is discharged into the public water area or reused in the middle water.

That is, the present invention
In a method for treating high-concentration organic wastewater that contains at least one of a dye and a pigment and is colored,
Performing a biological treatment of the organic waste water;
The present invention relates to a treatment method for high-concentration colored organic wastewater, comprising a step of adding ozone to the biological treatment water and performing a decolorization treatment.

The present invention also provides:
In an apparatus for treating high-concentration organic wastewater that contains at least one of a dye and a pigment and is colored,
Means for biological treatment of the organic waste water;
The present invention relates to a treatment apparatus for high-concentration colored organic wastewater, characterized by comprising means for adding ozone to the biological treatment water and performing a decolorization treatment.

[Action]
In general, an aerobic biological treatment method is effective as an economical wastewater treatment method for organic wastewater. Among conventional techniques, permeated water from a reverse osmosis membrane or distilled water from a distillation concentrator is difficult to biologically process because alcohols are high in concentration and almost alone. However, since the ink contains glycerin and glycol in an appropriate ratio in addition to alcohols, the ink waste liquid is more likely to biodegrade than the permeated water or distilled water when adjusted to the same concentration.

  Ozone treatment can be more effective for decolorization of dyes. However, when ink is directly decomposed with ozone, the consumption of ozone is large and organic substances are hardly decomposed. This is because, in ink waste liquids, organic substances such as glycerin, glycol, alcohol, and pigments consume ozone, so that sufficient ozone is not supplied until the oxidation of the dye. It is thought to increase.

  In other words, ink waste liquids can be treated more easily by biological treatment without separating glycerin or glycol without separating only alcohols using reverse osmosis membranes or distillation concentrators. Become. In the biological treatment process, the pigment is adsorbed and removed by the sludge.

  By the way, in the ozone treatment, if organic substances such as glycerin, glycol and alcohol such as ink waste liquid and pigments are removed in advance, the decolorization treatment can be performed by adding a small amount of ozone.

  That is, the organic wastewater is biologically treated for high-concentration organic wastewater containing and colored with at least one of a dye or a pigment, and a small amount of ozone is added to the treated water for economic treatment. Invented a method for decoloring.

  In this method, since the dye is also partially oxidized by the biological treatment, there is an effect that ozone consumption required for decolorization is further reduced.

  Surplus sludge is produced in biological treatment including the activated sludge method. Although this is not liquid waste, it must be treated as an industrial waste by a waste disposal specialist. Since sludge can be drastically reduced by general methods such as concentration and dehydration, its treatment is considerably more advantageous than liquid waste, but the amount of sludge generated is greatly increased by combining biological treatment methods and physicochemical treatment. It is also possible to reduce it to less.

  There is a sludge treatment technology that uses ozone in combination as one of the methods for reducing the amount of excess sludge discharged outside the system. According to this method, a decoloring effect by ozone can be expected. That is, this is a method in which treated water after biological treatment is subjected to ozone decoloration treatment, ozone treated water with residual ozone and surplus sludge are mixed, microbial cell membranes in surplus sludge are destroyed, and then returned to biological treatment for decomposition. With this method, ozone waste water can be decolorized and sludge can be reduced, and further processing of COD can be expected.

  Moreover, it is known that the activated sludge method mainly composed of Bacillus bacteria among biological treatments efficiently treats high-concentration organic wastewater and generates less excess sludge. Bacillus bacteria are endospore-forming bacteria, but the enzymes produced by Bacillus bacteria are used for high-concentration organic wastewater treatment because of their high ability to decompose organic matter. It can be expected to reduce.

  Bacteria belonging to the genus Bacillus, which is one of the effective microorganisms for organic wastewater treatment, are present in small numbers in general activated sludge, but the cell concentration is low. However, it is known that when a large amount of organic wastewater is used as a substrate and a large amount of silica or magnesium is applied as in the method employed in the present invention, cell disassembly and spore formation are promoted and proliferated and activated. .

  In the present invention, an attempt is made to apply the activated sludge method mainly based on the genus Bacillus to industrial organic wastewater such as ink waste liquid, that is, artificial chemical wastewater. However, high-concentration organic wastewater can be efficiently treated, and industrial wastewater can be made from activated sludge that is mainly composed of Bacillus bacteria.

  In the present invention, when the biological treatment is performed by an activated sludge method mainly composed of Bacillus bacteria, decolorization and decomposition of high-concentration organic substances are promoted by combination with the ozone treatment unit.

  According to the present invention, it is possible to purify and decolorize high-concentration organic wastewater containing and coloring at least one of a dye or a pigment, and can be discharged into public water areas such as rivers without generation of liquid waste. It can be reused as middle water, and it uses less ozone and saves energy, making it economical.

  In the present invention, the biological treatment is a method in which the main reaction is oxidative decomposition of organic substances by aerobic microorganisms, and may be a general activated sludge treatment, such as a circulation nitrification denitrification method, an anaerobic aerobic activated sludge method, a batch-type activity Includes sludge process and other activated sludge process modifications. The biofilm method may also be used.

  Among them, the activated sludge method mainly composed of Bacillus bacteria is desirable.

  In the latter stage of biological treatment, the treated water and sludge are separated using a solid-liquid separation means. The solid-liquid separation means may be any of a sedimentation basin, a pressurized flotation method, and a membrane separation method. May be either a microfilter or an ultrafiltration membrane.

  Ozone used for the ozone treatment may be generated by either a discharge method or an electrolysis method. The method of dissolving the generated ozone gas in the liquid may be a method in which the target liquid is circulated in a sealed state and the ozone gas is sucked and dissolved with an ejector, or the ozone gas is aerated. desirable.

  Now, the pigment is adsorbed by the sludge in the course of biological treatment, partly undergoes biodegradation for a long time, and part is discharged as excess sludge. When the activated sludge method that suppresses the generation of excess sludge is adopted, or when the pigment concentration is high and the sludge is accumulated earlier than biodegradation, the biological treatment efficiency is deteriorated.

  In order to increase the efficiency of biological treatment, it is better to remove only the pigment in advance. In that case, a method of performing biological treatment of the organic wastewater on the high concentration organic wastewater from which the pigment has been separated in advance by an ultrafiltration membrane or a microfiltration membrane, and decolorizing by adding ozone to the biological treatment water is considered. It is done. However, in the pretreatment of the ultrafiltration membrane or the microfiltration membrane, a liquid waste containing a pigment is generated although it is slight. Whether to improve the efficiency of biological treatment or allow the generation of liquid waste is a trade-off issue and depends on the case.

  FIG. 1 is a flow diagram showing an example of a high concentration organic wastewater treatment apparatus suitable for carrying out the high concentration organic wastewater treatment method of the present invention. However, the apparatus for realizing the method of the present invention is not necessarily in this form.

  In FIG. 1, high-concentration organic wastewater containing at least one of a dye and a pigment and colored is introduced as raw water 1 into an aeration tank 4 by a raw water pump 2 and a raw water transfer pipe 3.

  The aeration tank 4 includes an aeration device 5 and is filled with a mixed liquid of activated sludge 6 made of aerobic microorganisms. The air diffuser 5 is connected to the blower 7 and the air pipe 8 and blows the air sent from the blower 7 into the aeration tank 4 to mix the activated sludge 6 and the raw water 1 and supply oxygen to the activated sludge 6. Here, the raw water 1 is purified by the activity of aerobic microorganisms and led to the sedimentation basin 10 through the connecting pipe 9 while being mixed with the activated sludge 6. In the sedimentation basin 10, the supernatant liquid 11 and the precipitated sludge 12 are separated by the specific gravity difference.

  The sludge 12 is extracted from the sedimentation basin 10 by the air lift pump 13 and returned to the aeration tank 4 by the sludge transfer pipe 14. A part of the sludge 12 may be taken out of the system at this stage and subjected to sludge treatment using a concentration tank, a dehydrator, or the like. Other sludge 12 becomes activated sludge 6 again in the aeration tank 4. The supernatant liquid 11 separated by the sedimentation basin 10 is sent to the intermediate tank 16 by the supernatant liquid transfer pipe 15 and temporarily stored therein.

  The sealed ozone reaction tank 17 and the circulation pump 18 are connected by a suction-side circulation pipe 20, and the circulation pump 18 and the ozone gas suction mixing and dissolving device (ejector) 19 are connected by a discharge-side circulation pipe 21, and the discharge-side circulation pipe 21 returns to the ozone reaction tank 17 as it is. The ozone reaction tank inlet valve 22 is installed at a position where the suction-side circulation pipe 20 is branched, and the ozone reaction tank outlet valve 23 is installed at a position where the treated water pipe 26 is branched.

  Usually, the ozone reaction tank inlet valve 22 and the ozone reaction tank outlet valve 23 are closed.

  First, after the ozone reaction tank 17 is filled with the supernatant liquid 11, the circulation pump 18 is activated, the ozone generator 24 is activated, and the generated ozone gas is discharged from the ozone gas suction mixing and dissolving device (ejector) 19 through the ozone gas pipe 25. It is sucked by pressure and mixed with the supernatant liquid 11. In the ozone reaction tank 17, the dye of the supernatant liquid 11 is oxidatively decomposed by ozone and decolorization begins. In addition, it is quickly sucked into the circulation pump 18, mixed again with ozone sucked from the ozone gas suction mixing and dissolving device (ejector) 19 by negative pressure, and led to the ozone reaction tank 17. By repeating this circulation, the supernatant liquid 11 in the ozone reaction tank 17 is decolorized by continuously mixing with ozone and reacting repeatedly.

  The treated water 27 is discharged by opening the ozone reaction tank outlet valve 23. After draining the treated water 27 to the lowest water level at which the circulation pump 18 can operate, when the ozone reaction tank outlet valve 23 is closed again and then the ozone reaction tank inlet valve 22 is opened, the supernatant liquid 11 is transferred from the intermediate tank 16 to the circulation pump 18. The ozone reaction tank 17 is filled again by suction. Thereafter, the ozone treatment is performed in the same manner, so that the dye or the like of the supernatant liquid 11 is again oxidized and decolored by ozone, and this is repeated.

  The exhaust gas 28 containing unreacted ozone is exhausted after being detoxified by the exhaust gas treatment device 29.

[Example 1]
The ink waste liquid as the high-concentration organic waste water has the water quality shown in Table 1. This was treated as raw water 1 at a flow rate of 1.0 m ³ / day using the apparatus shown in FIG.

As an aerobic biological treatment, the aeration tank 4 was treated with an activated sludge method mainly composed of Bacillus bacteria with a capacity of 3.0 m ³ . In addition to ink waste liquid, this activated sludge was charged with 30 g / L of silica powder in addition to appropriate amounts of nitrogen and phosphorus, and was acclimatized under these conditions for 3 months. The silica powder used here is a trade name Bacillup manufactured by Sakai Perlite Co., Ltd., but may be a silica powder or the like separately prepared, or a mineral that elutes the silica component.

The sedimentation basin 10 which is a solid-liquid separator was 1.0 m ³ and the water area load was 1.0 m ³ / m ² / day. The sludge is drawn from the sedimentation basin by an air lift pump and flows into the aeration tank so that the sludge is circulated.

  The supernatant 11 of the sedimentation tank is temporarily stored in the intermediate tank 16 and then sent to the ozone reactor.

The ozone reaction device has a basic structure in which the sealed ozone reaction tank 17 is 1.0 m ³ and a circulation pump and an ejector are attached. The supernatant is first stored in a sealed tank, and then the ejector is connected to the ejector by the circulation pump. Circulate in a closed tank. At that time, the ozone gas produced by the ozone generator is sucked by the ejector and mixed and dissolved in the supernatant by circulation. The dye component in the supernatant is decolorized by ozone at this time.

  The amount of ozone used at this time was 20 g.

  The decolorized liquid is guided to the treated water tank by opening a valve attached to the discharge side of the circulation pump, and is discharged to a river or the like after pH treatment. Moreover, the supernatant liquid of an intermediate | middle tank is made to flow in by opening the valve | bulb attached to the circulation pump suction side after that.

  Table 1 shows the water quality of the high-concentration organic waste water employed in this example, the treated water of the biological treatment unit, and the treated water quality of the ozone treatment unit.

  Although the absorbance was 156 to 711 depending on the wavelength, it dropped from 0.012 to 0.205, and the treated water could be treated to the extent that it was transparent and no color was observed. As for the organic matter concentration, BOD 3500 mg / L can be processed up to 20 mg / L, and COD 4400 mg / L can be processed up to 65 mg / L. This is a level that does not cause any problem in normal discharge into rivers and is considered to have been sufficiently purified. It is also at a level where the treated water can be used as raw water to study the use of medium water.

  Here, the method for evaluating the degree of coloration of the waste water was based on absorbance, and the measured wavelength range was 380 nm to 660 nm, and the cell length converted to 50 mm was used. The cell length converted to 50 mm is as shown in the following formula.

  Cell length 50 mm conversion value = absorbance measurement value × dilution ratio × 50 mm / cell length (mm) used in measurement.

[Comparative example]
As a comparative example, Table 2 shows an example in which the same ink waste liquid as in Example 1 was diluted three times with distilled water and directly treated with ozone alone.

  The absorbance decreased from 0.023 to 1.707 depending on the wavelength. Even at this level, the treated water was transparent and no color was observed. However, regarding the organic matter concentration, the BOD was 1180 mg / L, and the COD was 1350 mg / L, but this was obtained by ozone treatment of the ink wastewater diluted three times, so it was hardly treated. . The amount of ozone used was 360 g, which required 18 times as much ozone as the above examples. Further, the pH of the treated water was considerably lower than that in the above example, and was lowered to 3.2.

It is a flowchart which shows an example of the processing apparatus of the high concentration organic wastewater suitable for implementing the processing method of the high concentration organic wastewater of this invention. It is a flowchart which shows the ozone apparatus implemented as a comparative example.

Explanation of symbols

1 Raw Water 2 Raw Water Pump 3 Raw Water Transfer Piping 4 Aeration Tank 5 Air Diffuser (Pipe)
6 Activated sludge 7 Blower 8 Air piping 9 Connection piping
10 Sedimentation basin (tank)
11 Supernatant
12 Sludge
13 Air lift pump
14 Sludge transfer piping
15 Supernatant transfer piping
16 Intermediate tank
17 Ozone reactor
18 Circulation pump
19 Ozone gas suction mixing and dissolving device (ejector)
20 Suction side circulation piping
21 Discharge side circulation piping
22 Ozone reaction tank inlet valve
23 Ozone reactor outlet valve
24 Ozone generator
25 Ozone gas piping
26 Treated water piping
27 Treated water
28 exhaust gas
29 Exhaust gas treatment equipment
30 exhaust

Claims (17)

In a method for treating high-concentration organic wastewater that contains at least one of a dye and a pigment and is colored,
Performing a biological treatment of the organic waste water;
And a step of decolorizing treatment by adding ozone to the biological treatment water.   The treatment method according to claim 1, wherein the biological treatment is an activated sludge method mainly comprising Bacillus bacteria.   The treatment method according to claim 2, wherein the activated sludge is cultivated in advance using an organic material of the same kind as the contaminating component contained in the high-concentration organic wastewater to be treated.   The processing method according to any one of claims 1 to 3, wherein the ozone is added by dissolving ozone by an ejector in the step of decoloring by adding ozone.   A solid-liquid separation means for separating treated water and sludge is provided at a subsequent stage of the biological treatment step, and the solid-liquid separation means is any one of a sedimentation basin, a pressurized flotation method and a membrane separation method. 4. The processing method according to any one of 4 above.   The processing method according to claim 5, wherein the solid-liquid separation means is a membrane separation method using a microfilter or an ultrafiltration membrane.   The processing method in any one of Claims 1-6 which has the process of removing a pigment with an ultrafiltration membrane or a microfiltration membrane beforehand before the said biological treatment process.   The processing method according to any one of claims 1 to 7, wherein ozone is exhausted after detoxifying ozone in the exhaust gas generated in the step of decoloring by adding ozone. In an apparatus for treating high-concentration organic wastewater that contains at least one of a dye and a pigment and is colored,
Means for biological treatment of the organic waste water;
A treatment device for high-concentration colored organic wastewater, comprising means for adding ozone to the biological treatment water and performing a decolorization treatment. The biological treatment means is
The processing apparatus of Claim 9 which has an aeration layer, the aeration means provided in this aeration layer, and the activated sludge with which it fills in this aeration layer and has the capability to decompose | disassemble the said organic waste water.   11. The treatment apparatus according to claim 10, wherein the activated sludge is mainly composed of Bacillus bacteria.   12. The treatment apparatus according to claim 11, wherein the activated sludge is preliminarily cultured with an organic substance of the same kind as the contaminating component contained in the high-concentration organic wastewater to be treated.   The processing apparatus according to any one of claims 9 to 12, wherein, in the means for decoloring by adding ozone, the ozone adding means is an ejector for dissolving ozone.   The solid-liquid separation means for separating treated water and sludge after the biological treatment means, and the solid-liquid separation means is any one of a sedimentation basin, a pressurized flotation device, and a membrane separation device. The processing apparatus in any one.   15. The processing apparatus according to claim 14, wherein the solid-liquid separation means is a membrane separation apparatus having a microfilter or an ultrafiltration membrane.   The processing apparatus according to any one of claims 9 to 15, further comprising means for removing the pigment in advance by an ultrafiltration membrane or a microfiltration membrane before the biological treatment means.   The processing apparatus according to any one of claims 9 to 16, further comprising an exhaust gas processing apparatus that detoxifies ozone in the exhaust gas generated by the decoloring process by adding ozone.

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