JP2004358421A - Method and apparatus for decoloring colored beverage wastewater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for decoloring colored beverage wastewater which efficiently decolors the colored beverage wastewater without generating sludge. <P>SOLUTION: In the method for decoloring the colored beverage wastewater after oxidizing and decoloring colored components in the colored beverage wastewater by adding an oxidizing agent to the colored beverage wastewater and mixing them, the wastewater is treated with a catalyst to accelerate decolonization. The apparatus for decoloring the colored beverage wastewater has a regulation tank 11 having a mixing means 31, an oxidizing agent addition means that adds the oxidizing agent to the regulation tank 11, and a catalyst tower 13 into which overflow water from the regulation tank 11 is introduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for decolorizing colored beverage wastewater, and in particular, efficiently decolorizes colored beverage wastewater without generating waste such as sludge due to the use of a flocculant performed in a conventional decolorizing process. Method and apparatus.
[0002]
[Prior art]
Wastewater generated in the beverage manufacturing process (hereinafter referred to as “drinkage wastewater”) is discharged to rivers and the like after various treatments in consideration of safety and the environment. If the drinking water is colored, the wastewater treatment is intended for decolorization.
[0003]
A conventional method for decolorizing colored beverage wastewater involves agglomerating a colored component in the wastewater with a flocculant to precipitate and separate. That is, as shown in FIG. 8, first, colored beverage wastewater is introduced into the reaction tank a, and a predetermined amount of an inorganic coagulant, for example, ferric chloride is charged into the reaction tank a to react with the colored component. To electrically neutralize the surface charge of the particles to form aggregates. At the same time, a pH adjuster, for example, caustic soda is added to adjust the pH of the aggregate to an appropriate range. Next, the waste water having undergone the reaction is introduced into the flocculation tank b, and a polymer flocculant is introduced into the waste water to increase the strength and particle size of the aggregate of the colored component, and the waste water containing the aggregate is precipitated. The mixture is introduced into the tank c, and the aggregate d is precipitated and separated in the precipitation tank c. The supernatant water of the sedimentation tank c from which the colored components are sedimented and separated is then discharged after being disinfected in a disinfection step. On the other hand, the aggregates d containing the precipitated colored components are periodically removed from the sedimentation tank c, and are separately treated as sludge and then discarded.
[0004]
[Problems to be solved by the invention]
Such a conventional decolorization method involves coagulating and sedimenting colored components in beverage wastewater with an inorganic coagulant and a polymer coagulant.Since sludge is discharged from a sedimentation tank, cost and cost for the treatment are increased. There is a labor problem. Also, from the viewpoint of protection of the natural environment, there is a strong demand for reduction of waste generation.
[0005]
An object of the present invention is to solve the problems of the above-mentioned conventional decoloring method and to provide a method and an apparatus for efficiently decolorizing colored beverage wastewater without generating sludge.
[0006]
[Means for Solving the Problems]
The method for decolorizing colored beverage effluent of the present invention is a method for decolorizing colored beverage effluent comprising a decolorizing step of bringing the colored beverage effluent into contact with a catalyst in the presence of an oxidizing agent. And a contacting step of bringing the colored beverage wastewater mixed with the oxidizing agent into contact with a catalyst.
[0007]
The apparatus for decolorizing colored beverage wastewater of the present invention comprises an adjusting tank provided with a mixing means for the liquid in the tank, a means for introducing colored beverage wastewater into the adjusted tank, and a colored beverage wastewater introduced into the adjusted tank and / or It is characterized by comprising an oxidizing agent adding means for adding an oxidizing agent to the adjusting tank, and a catalyst tower into which effluent from the adjusting tank is introduced.
[0008]
According to the present invention, the oxidizing agent is added to and mixed with the colored beverage wastewater to oxidize and decolorize the colored components in the colored beverage wastewater, and thereafter, by contacting with a catalyst, the decolorization is promoted, and the colored beverage is promoted. The wastewater can be highly decolorized, and treated water of good quality can be obtained stably and efficiently.
[0009]
ADVANTAGE OF THE INVENTION According to this invention, it is possible to perform decoloring of the same level or more as before, without generating sludge due to aggregation of colored components, and extremely efficiently, and is also excellent in terms of environmental protection. . Moreover, according to the present invention, it is possible to remove hardly decomposable components in colored beverage wastewater, which is effective for improving the quality of treated water.
[0010]
In the present invention, the decolorized water may be further treated with activated carbon. Therefore, in the decolorizing apparatus for colored beverage wastewater of the present invention, an activated carbon tower into which the effluent of the catalyst tower is introduced may be provided. Thereby, for example, chlorine generated by the decolorizing treatment using a chlorine-based oxidizing agent can be removed by activated carbon, and the remaining hardly decomposable components can be removed by adsorbing the activated carbon. Further, prior to the decolorization treatment, the colored beverage wastewater may be filtered to remove foreign substances in the beverage wastewater.
[0011]
Further, in the present invention, when a chlorine-based oxidizing agent is used as the oxidizing agent, the residual chlorine concentration of the decolorized water may be measured immediately after the decolorizing treatment. Therefore, in the apparatus for decolorizing colored beverage wastewater of the present invention, a measuring means for measuring the residual chlorine concentration of the effluent of the catalyst tower may be provided. By doing so, it is possible to easily calculate the chromaticity of the decolorized water from the measured residual chlorine concentration without requiring a complicated operation of measuring the chromaticity of the decolorized water by absorbance measurement or the like. Becomes possible. Further, in the present invention, it is also possible to control the amount of the chlorine-based oxidizing agent to be added based on the measured residual chlorine concentration, thereby adding an appropriate amount of the chlorine-based oxidizing agent to the colored beverage wastewater. Thus, the chromaticity of the decolorized water can be efficiently brought close to a predetermined set value.
[0012]
In the present invention, the oxidizing agent preferably includes sodium hypochlorite. Further, as the catalyst, preferably, a nickel peroxide-supported catalyst is used.
[0013]
In the present invention, the step of mixing the colored beverage wastewater and the oxidant is preferably performed for a time until the chromaticity of the mixed liquid of the colored beverage wastewater and the oxidant reaches a predetermined chromaticity. The mixing time is appropriately set according to the chromaticity of the colored beverage wastewater, the amount of the oxidizing agent added, the desired chromaticity, and the like. When the mixing is performed by stirring, the mixing time is, for example, 10 minutes or more. Can be.
[0014]
Also, the contacting step between the mixed solution and the catalyst is preferably performed for a time until the chromaticity of the obtained decolorized water reaches a predetermined chromaticity. The contact time is also appropriately determined according to the water quality and treatment amount of the colored beverage effluent, the amount of the oxidizing agent added, the amount of the catalyst used, the desired chromaticity, and the like. The residence time in the column (time passing through the catalyst column) is preferably, for example, 6 minutes or more.
[0015]
In the present invention, a part of the decolorization treatment water may be returned to the decolorization step and subjected to the circulation treatment. That is, in the apparatus for decolorizing colored beverage wastewater of the present invention, a circulation line for returning part of the effluent of the catalyst tower to the adjustment tank may be provided. By performing the circulation processing in this manner, it becomes possible to circulate the treated water having the chromaticity equal to or higher than the reference value and to perform the processing again, and it is possible to perform the decoloring processing reliably. In addition, by circulating the water containing the residual oxidizing agent in this manner, a part or all of the oxidizable substance attached to the catalyst is removed, and the metal oxide and the oxidizable substance during the water supply stop period are removed. It is possible to improve the durability of the catalyst by the effect of preventing the elution of the metal component due to the reaction with the catalyst.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a system diagram showing an embodiment of a decolorizing device (hereinafter, simply referred to as a “decolorizing device”) 10 for colored beverage wastewater of the present invention. Such a decolorizing apparatus is incorporated in, for example, the decolorizing processing section 4 of the colored beverage wastewater treatment system shown in FIG. The colored beverage wastewater treatment system 1 shown in FIG. 2 includes a biological treatment unit 2, a filtration treatment unit 3, a decolorization treatment unit 4, and a disinfection treatment unit 5, and the colored beverage wastewater is treated by these treatment units. Released after processing. The biological processing unit 2, the filtration processing unit 3, and the disinfection processing unit 5 can have the same structure and function as those in the conventional processing system, and a detailed description thereof will be omitted.
[0018]
In the decolorizing apparatus 10 shown in FIG. 1, the colored beverage wastewater to be treated by the conduit 20 is introduced from the filtration processing unit 3 including the raw water tank 3A and the filter 3B, and the regulating tank 11 and the regulating tank 11 for accommodating the same. An oxidizing agent storage tank 12 for storing the oxidizing agent to be supplied, a catalyst tower 13 connected to the adjusting tank 11 via a conduit 21 downstream of the adjusting tank 11 (as viewed in the flow direction of wastewater), and a catalyst tower 13 On the downstream side (as viewed in the flow direction of the wastewater), there is provided an activated carbon tower 14 connected to the catalyst tower 13 via a conduit 22 with a valve 41. At least one supply pipe 24 is connected to the oxidant storage tank 12, and the oxidant stored in the oxidant storage tank 12 is supplied to the adjustment tank 11 via the supply pipe 24 by the pump 33. I have. Therefore, in this embodiment, the oxidizing agent storage tank 12, the pump 33, and the supply pipe 24 constitute oxidizing agent adding means. In the present embodiment, liquid sodium hypochlorite is used as the oxidizing agent, but an oxidizing agent using another chlorine-based compound can also be used. The regulating tank 11 is provided with at least one (two in this embodiment) stirrer 31 so that the colored beverage wastewater and the oxidizing agent can be mixed by stirring.
[0019]
A pump 32 is connected to the conduit 21 connected to the regulating tank 11 adjacent to the regulating tank 11, and the pump 32 oxidizes and decolorizes the drinking water from the regulating tank 11 to the catalyst tower 13 at a desired flow rate via the conduit 21. And an oxidizing agent. The catalyst tower 13 is filled with a desired amount of a metal oxide catalyst by a known method, and the mixed solution of the drinking water and the oxidizing agent that is oxidized and decolorized in the adjusting tank 11 in the catalyst tower 13 is subjected to the metal oxidation. It can be brought into contact with the catalyst. In the present embodiment, a nickel peroxide-carrying catalyst is used as an example of such a metal oxide catalyst, but another catalyst that promotes the oxidation-reduction reaction of a metal may be used. The activated carbon tower 14 is filled with known activated carbon, and comes into contact with decolorized water sent from the catalyst tower 13 to remove chlorine and hardly decomposable components in the water. A conduit 23 provided with a valve 42 is connected to the outlet side of the activated carbon tower 14 so that the water treated in the activated carbon tower 14 is sent to the disinfection processing section 5. One end of a return conduit 25 provided with a valve 43 is connected to the conduit 23 between the activated carbon tower 14 and the valve 42, and the return conduit 25 returns the return flow into the regulating tank 11. One end of a branch pipe 26 provided with a valve 44 is connected to the conduit 22 connected to the outlet side of the catalyst tower 13, and the other end of the branch pipe 26 is connected to the return conduit 25. Further, a chlorine concentration measuring device 47 is provided on the catalyst tower 13 side of the conduit 22.
[0020]
In addition, 27 is a conduit for backwashing the activated carbon tower 14 using the decolorized water sent from the catalyst tower 13, and 45 is a valve provided in the conduit 27. Reference numeral 29 denotes a conduit for sending backwash wastewater from the activated carbon tower 14 to the gray water drainage tank 15, and reference numeral 46 denotes a valve provided in the conduit 29. An air vent line 28 with a valve is connected to the catalyst tower 13 and the activated carbon tower 14.
[0021]
In the present embodiment, one catalyst tower 13 and one activated carbon tower 14 are provided, but a plurality of these may be provided in series and / or in parallel according to the treatment conditions of colored beverage wastewater. Absent.
[0022]
Next, the operation of the decolorizing apparatus 10 will be described.
[0023]
The filtered colored beverage wastewater sent from the filtration unit 3 is introduced into the adjusting tank 11. A liquid oxidizing agent, for example, an aqueous solution of sodium hypochlorite is supplied from the oxidizing agent storage tank 12 through the conduit 24 into the adjusting tank 11. In the adjustment tank 11, the beverage effluent and the oxidant are stirred by the stirrer 31, and the oxidant and the beverage effluent are mixed. The amount of the liquid oxidizing agent varies depending on the type and the chromaticity of the drinking water, and is, for example, 10 to 800 mg-Cl / L as sodium hypochlorite per liter of the drinking water. Sodium chlorite is stirred by the stirrer 31 for a desired time, for example, 10 minutes or more, preferably 10 to 20 minutes. In the regulating tank 11, the drinking water is oxidized and the colored components are partially decolorized, and then sent to the catalyst tower 13 via the conduit 21 by the pump 32. In the catalyst tower 13, the oxidized beverage wastewater comes into contact with a catalyst (in this embodiment, a nickel peroxide-supported catalyst), thereby facilitating decolorization of the colored component. The required contact time between the inflow water from the adjustment tank 11 and the catalyst in the catalyst tower 13 varies depending on the type, amount, chromaticity, type and amount of the oxidizing agent and the catalyst, etc. This is a range in which colored components that could not be decolorized by oxidation with an oxidizing agent can be decolorized to an acceptable value, and in this embodiment, it is desirable that the contact be performed for 6 minutes or more, for example, 6 to 30 minutes.
[0024]
The water decolorized to an acceptable range by contact with the catalyst in the catalyst tower 13 is sent to the activated carbon tower 14 where it is brought into contact with the activated carbon filled therein, and the remaining oxidizing agent component such as residual chlorine And hardly decomposable components are removed. The effluent from the activated carbon tower 14 is sent to the disinfection processing section 5.
[0025]
When returning a part of the effluent of the activated carbon tower 14 to the regulating tank 11, the valve 43 is opened and returned via the return conduit 25.
[0026]
Further, a chlorine concentration measuring device 47 is provided at the outlet of the catalyst tower 13 to measure the residual chlorine concentration of the decolorized water treated in the catalyst tower 13, and when the concentration is lower than a predetermined concentration, the valve 44 is opened and the catalyst tower is opened. 13 is returned to the regulating tank 11 through the return conduit 25, or the valve 42 is closed and the valve 43 is opened to prevent foreign matter from entering the regulating tank 11, and the effluent of the activated carbon tower 14 is returned to the return conduit 25. It is configured to return to the adjustment tank 11 through 25 and perform the oxidative decolorization treatment again. Further, based on the measured value of the residual chlorine concentration, the pump 33 of the oxidizing agent storage tank 12 can be controlled to adjust the oxidizing agent addition amount.
[0027]
In FIG. 1, valves 48 and 49 are used for cleaning the catalyst in the catalyst tower 13. In the cleaning of the catalyst, the valve 44 and the valve 49 are opened, the valve 48 is closed, and the washing water is passed through the catalyst tower 13 to wash the catalyst, and the washed washing water is discharged to the raw water tank.
[0028]
By the way, in the decoloring apparatus as shown in FIG. 1, when the treatment is performed by passing drinking effluent containing an oxidizing agent through a catalyst tower filled with a metal oxide catalyst, the amount of water varies, holidays, maintenance and inspection of the apparatus, and the like. Therefore, the operation of the device may be stopped. In this case, after the operation is stopped for a predetermined time, when the flow of the drinking water to the catalyst tower is resumed, the metal component of the metal oxide catalyst is eluted into the obtained decolorized water, whereby the processing at the time of restarting the operation is performed. As the water quality of water decreases, the metal oxide catalyst in the catalyst tower deteriorates due to elution of the metal component, and the catalyst performance may decrease.
[0029]
This is because when the flow of beverage wastewater to the catalyst tower is stopped, the oxidizing agent is decomposed and removed in the catalyst tower, and the oxygen of the metal oxide on the catalyst surface and the remaining beverage adsorbed on the catalyst This is because the metal oxide of the catalyst is reduced and the metal component is eluted by the reaction with the oxidizable substance such as the colored component in the waste water.
[0030]
Therefore, in the present invention, in order to prevent such metal components from being eluted from the metal oxide catalyst, the oxidizing agent in the water passed through the catalyst tower before stopping the flow of water when the operation of the apparatus is stopped. The density may be increased. By doing so, part or all of the oxidizable substance adhered to the catalyst is removed, and elution of the metal component due to the reaction between the metal oxide and the oxidizable substance during the water suspension period is prevented. can do.
[0031]
In order to increase the oxidizing agent concentration in the water passed through the catalyst tower, it is only necessary to increase the amount of the oxidizing agent added to the colored beverage effluent. Therefore, it is difficult to control the concentration of the oxidizing agent. Therefore, instead of colored drinking water, water having a low oxidizable substance concentration such as city water or industrial water may be used, and an oxidizing agent may be added to the city water or industrial water to flow through the catalyst tower. Further, the concentration of the oxidizing agent in the water introduced into the catalyst tower may be increased, and the effluent from the catalyst tower may be circulated again so as to flow through the catalyst tower.
[0032]
Specifically, in the decoloring apparatus of FIG. 1, when stopping the water supply, city water or industrial water is introduced into the regulating tank 11 instead of the colored drinking water drainage, and the concentration of the oxidizing agent is lower than that in the normal operation. Make it higher. Then, the valve 43 is closed, the valves 44 and 48 are opened, and the water in the adjustment tank 11 is passed through the catalyst tower 13, and the entire amount of the effluent from the catalyst tower 13 is returned to the adjustment tank 11 and circulated. . As a result, water having a high oxidizing agent concentration is circulated and circulated through the catalyst tower 13, and oxidizable substances such as colored components remaining on the catalyst in the catalyst tower 13 are decomposed and removed. . In this case, since water having a high oxidant concentration does not flow out of the system during the circulation, the treatment cost for that purpose is suppressed, and the oxidant flowing out of the catalyst tower 13 is reused, so that the oxidant chemical cost is reduced. Can be reduced.
[0033]
In the case of circulating water having a high oxidizing agent concentration, the oxidizing agent-containing water may be further circulated even after the oxidizable substances such as the colored components attached to the catalyst are decomposed and exhausted. Circulation may be continued throughout the entire period. In this case, the oxidizing agent gradually decomposes by the action of a catalyst during the circulation, and the concentration of the oxidizing agent in the water in the catalyst tower decreases. As a result, the concentration of the oxidizing agent in the water flowing out of the catalyst tower at the time of restarting the operation becomes low, and it is not necessary to perform the oxidizing agent removal treatment on the initial effluent of the catalyst tower, or a simple one is sufficient. Become like
[0034]
When increasing the oxidant concentration in the water at the time of stopping the flow of water, the oxidant concentration in the catalyst tower inflow water is 1.0 to 40 times the oxidant concentration in the catalyst tower inflow water during normal operation, particularly 2.0 to 10 times. Preferably. Further, it is desirable that the water having a high oxidizing agent concentration be passed through the catalyst tower in an amount of at least 30 times the volume of the catalyst tower, particularly at least 50 times, to sufficiently decompose the oxidizable substances such as attached colored components. .
[0035]
When the operation is restarted after the operation suspension period ends, the flow of colored beverage wastewater is restarted.However, in the early stage of operation restart, the effluent from the catalyst tower contains a large amount of oxidizing agent. There is. In the apparatus of FIG. 1, the remaining oxidant is removed by the activated carbon tower 14. However, the effluent of the catalyst tower at the initial stage of the resumption of water flow is returned to the adjustment tank 11 for dilution or transferred to another processing system for processing. You may.
[0036]
In the present invention, the oxidizing agent added to the colored beverage wastewater is preferably a chlorine-based oxidizing agent. The chlorinated oxidizing agent is not particularly limited, and in addition to sodium hypochlorite as described above, for example, chlorine, potassium hypochlorite, hypochlorite such as calcium hypochlorite, sodium chlorite, Examples include chlorites such as potassium chlorite, chlorates such as sodium chlorate, potassium chlorate and calcium chlorate, and perchlorates such as sodium perchlorate and calcium perchlorate. Of these, hypochlorites such as sodium hypochlorite have suitable oxidizing properties and can be suitably used.
[0037]
If the amount of the oxidizing agent added to the colored beverage wastewater is too small, the decolorizing treatment becomes insufficient, and if it is too large, a large amount of the oxidizing agent may remain in the treated water. When the oxidizing agent is a chlorine-based oxidizing agent, it is preferable to add the chlorine-based oxidizing agent such that the residual chlorine concentration in the colored beverage wastewater is 10 to 400 mg-Cl / L. In addition, "mg-Cl / L" is a residual chlorine concentration in water, which is obtained by converting a chlorine-based oxidizing agent remaining in treated water into chlorine.
[0038]
In the present invention, as the catalyst, a metal oxide catalyst is preferable, and as the metal oxide catalyst, a metal oxide as a catalyst component supported on a carrier is preferable. As the carrier, one or more of various types of zeolite and alumina can be used.
[0039]
Examples of the metal of the catalyst component include nickel, cobalt, copper, silver and the like, preferably nickel and cobalt, and particularly preferably nickel. One of these catalyst metals may be used alone, or two or more thereof may be used in combination.
[0040]
The metal oxide catalyst used in the present invention is preferably such that these catalyst metals are supported on a carrier as a metal oxide, preferably a metal peroxide. It is preferable that the carrier is 0.1 to 100 g-metal / 1000 g-dry carrier in terms of the amount of catalyst metal supported. If the amount is less than this, the catalytic action of the metal oxide cannot be sufficiently obtained, and it is difficult to support the metal oxide in a larger amount in preparation of the catalyst.
[0041]
The metal peroxide-supported catalyst suitable for the present invention can be prepared, for example, by allowing a catalyst metal such as nickel to be supported on a carrier and then reacting with an oxidizing agent as follows.
[0042]
First, an aqueous solution of a sulfate, nitrate, chloride, or the like of a catalyst metal such as nickel, or an aqueous solution of a mixture thereof is prepared, and the carrier is immersed in the aqueous solution of the catalyst metal. Alternatively, the catalyst metal aqueous solution is passed through the column filled with the carrier in a one-time or circulation manner to make contact therewith. The concentration of the catalyst metal aqueous solution and the contact time are appropriately set according to the amount of metal supported on the prepared metal peroxide-supported catalyst. After the carrier carrying the catalyst metal such as nickel by ion exchange is washed with water in this manner, the carrier is brought into contact with an alkaline aqueous solution containing an oxidizing agent. This contacting method can be carried out by immersion or by passing water through a column, as in the above-described supporting method. As the oxidizing agent for supporting the catalyst, hypochlorite such as sodium hypochlorite, chlorine gas, or the like can be used. As the alkaline aqueous solution for supporting the catalyst, an aqueous solution of sodium hydroxide, potassium hydroxide or the like can be used. The concentration of the oxidizing agent and the alkali in the aqueous alkali solution containing the oxidizing agent are not particularly limited, but are usually 0.5 to 10% by weight, particularly 1 to 5% by weight, and the alkali concentration is 0.1 to 10%. It is preferably an aqueous solution having a concentration of 0.5% by weight, particularly 0.5 to 2.5% by weight.
[0043]
In this way, the carrier supporting the catalyst metal such as nickel is brought into contact with an alkaline aqueous solution containing an oxidizing agent, and then washed with water, whereby a metal peroxide-supported catalyst suitable for the present invention can be obtained.
[0044]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0045]
The colored beverage wastewater was biologically treated in the biological treatment section 2 in the same manner as in the related art, and then filtered in the filtration treatment section 3. The chromaticity of the drinking water after filtration was 1200. When this drinking water was treated by the conventional decoloring method using a coagulant shown in FIG. 8, the chromaticity of the treated water was 100 to 200.
[0046]
A decolorization test of beverage wastewater having such chromaticity was performed using a test device 50 shown in FIG.
[0047]
Pumping the above-mentioned drinking water in the raw water tank 51 ₁ To the adjusting tank 53 at a flow rate of 180 tons / h, and pump the sodium hypochlorite aqueous solution in the oxidizing agent storage tank 52 with the pump P. ₂ To the adjustment tank 53 at a predetermined ratio. Then, in the adjustment tank 53, the beverage wastewater and sodium hypochlorite were stirred and mixed for a predetermined time by the stirrer 53A to perform a decolorizing treatment. Pump P ₃ Then, the mixture was passed through the catalyst tower 54 at a flow rate such that the mixed solution and the catalyst were continuously contacted for a predetermined time, followed by decolorizing the catalyst. As the catalyst, a nickel peroxide-supported catalyst was used.
[0048]
In this test, the state of decolorization due to the reaction between the beverage wastewater and sodium hypochlorite in the adjustment tank 53 was determined by adding the amount of sodium hypochlorite to 100, 200, 400, or 800 mg-Cl / L. In the case where the stirring time in the adjusting tank 53 is variously changed from 10 minutes to 1080 minutes, the stirring time and the chromaticity of the oxidized decolorized water (outflow water of the adjusting tank 53) are changed. When the relationship was obtained, the result shown in FIG. 4 was obtained. In addition, the relationship between the residual chlorine concentration of the oxidative decolorization treated water and the stirring time was as shown in FIG.
[0049]
As is clear from FIG. 4, even when the amount of sodium hypochlorite added is variously changed, the chromaticity of the drinking water, which is the water to be treated, rapidly decreases to 200 to 400 by stirring for about 10 minutes. It can be seen that, after stirring for a certain period of time, the chromaticity hardly changes even if stirring is continued. Further, in order to decolorize the chromaticity of the beverage wastewater to 100, which is the same level as the processing ability of the conventional decoloring method, the stirring time had to be 1080 minutes. On the other hand, the residual chlorine concentration in the oxidatively decolorized water also decreases until stirring for several minutes, as shown in FIG. 5, but hardly decreases thereafter. It can also be seen that the residual chlorine concentration increases with an increase in the amount of sodium hypochlorite added.
[0050]
From these results, the degree of decolorization by the oxidizing agent can be determined by setting a predetermined stirring time for each oxidizing agent concentration to be added, and this control can be performed by measuring the residual chlorine concentration. I understand.
[0051]
In the same test, the amount of sodium hypochlorite added was changed at a rate of 150, 300, or 470 mg-Cl / L, and the drinking water having a chromaticity of 1193 (Test 1) and the drinking water having a chromaticity of 780 (Test 1) were used. 2) Drinking wastewater with a chromaticity of 1183 (Test 3) and drinking water with a chromaticity of 1272 (Test 4), respectively. When the relationship with the amount of sodium acid added was examined, it was as shown in FIG. From these results, it can be seen that when the amount of sodium hypochlorite added exceeds a predetermined amount (about 150 mg-Cl / L), the chromaticity after decolorization hardly changes even if the amount of addition is large. It can be seen that the concentration of the oxidizing agent can be determined according to the desired chromaticity.
[0052]
Further, 470 mg-Cl / L of sodium hypochlorite was added, and the mixture was stirred and mixed for 20 minutes, and the contact time between the water after oxidative decolorization and the catalyst in the catalyst tower 54 and the decolorized water after contact (catalyst) The relationship with the chromaticity of the water at the tower outlet) was examined, and the result was as shown in FIG. From FIG. 7, it can be seen that by setting the contact time between the catalyst and the oxidatively decolorized water to 6 minutes or more, the wastewater near the chromaticity of 80 can be reduced to about 50. If the contact time is longer, the chromaticity can be lowered, but if the contact time is longer than 6 minutes, no significant reduction effect is observed.
[0053]
In the present embodiment, the amount of sodium hypochlorite added was 180 mg-Cl / L, and the stirring time in the adjustment tank 53 was 10 minutes. By setting the contact time to 6 minutes, decolorized water having a chromaticity of 100 or less and an average of 70 could be obtained.
[0054]
【The invention's effect】
As described in detail above, according to the method and apparatus for decolorizing colored beverage wastewater of the present invention, the following effects can be obtained.
(A) Decolorization of colored beverage wastewater is promoted by catalytic treatment after oxidative decolorization, and no sludge is generated unlike the conventional method, eliminating the problem of sludge treatment and decoloring at least equivalent to the conventional method. The effect can be obtained.
(B) By promoting the decolorization by performing a catalyst treatment, highly efficient decolorization can be performed very efficiently, and high-quality treated water can be stably obtained. In addition, it becomes possible to remove hardly decomposable components.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of a colored beverage waste water decoloring apparatus of the present invention.
FIG. 2 is a system diagram of a treatment system for colored beverage wastewater.
FIG. 3 is a system diagram showing a test apparatus used in an example.
FIG. 4 is a graph showing the relationship between stirring time and chromaticity.
FIG. 5 is a graph showing a relationship between a stirring time and a residual chlorine concentration.
FIG. 6 is a graph showing the relationship between the amount of added sodium hypochlorite and chromaticity.
FIG. 7 is a graph showing a relationship between a contact time with a catalyst and chromaticity.
FIG. 8 is a schematic diagram illustrating a conventional method for decolorizing colored beverage wastewater.
[Explanation of symbols]
3 Filtration section
5 Disinfection processing section
10 Decoloring device
11 adjustment tank
12 Oxidant storage tank
13 Catalyst tower
14 Activated carbon tower

Claims (13)

A method for decolorizing colored beverage wastewater comprising a decolorizing step of contacting colored beverage wastewater with a catalyst in the presence of an oxidizing agent,
The decolorizing step includes a mixing step of adding and mixing an oxidizing agent to the colored beverage wastewater and a contacting step of bringing the colored beverage wastewater mixed with the oxidizing agent into contact with a catalyst, wherein the decolorizing of the colored beverage wastewater is performed. Method. The method for decolorizing drinking water according to claim 1, further comprising an activated carbon treatment step of treating the treated water in the decolorizing step with activated carbon. The method for decolorizing colored beverage wastewater according to claim 1 or 2, further comprising a filtration step of filtering the colored beverage wastewater to be supplied to the decolorizing step. The method for decolorizing colored beverage wastewater according to any one of claims 1 to 3, wherein the oxidizing agent is a chlorine-based oxidizing agent, and a residual chlorine concentration of the treated water in the decolorizing step is measured. How to decolor wastewater. The method for decolorizing colored beverage wastewater according to claim 4, wherein the amount of the chlorine-based oxidizing agent added in the mixing step is controlled in accordance with the measured residual chlorine concentration. The method for decolorizing colored beverage wastewater according to any one of claims 1 to 5, wherein the oxidizing agent is sodium hypochlorite. The method for decolorizing colored beverage wastewater according to any one of claims 1 to 6, wherein the mixing step is performed for a time until a mixed solution of the colored beverage wastewater and the oxidant reaches a predetermined chromaticity. A method for decolorizing colored beverage wastewater. The method for decolorizing colored beverage wastewater according to any one of claims 1 to 7, wherein the catalyst is a nickel peroxide-supported catalyst. The method for decolorizing colored beverage wastewater according to any one of claims 1 to 8, wherein the contacting step is performed for a time until the chromaticity of the treated water reaches a predetermined chromaticity. Method. An adjustment tank provided with a mixing means for the liquid in the tank,
Means for introducing colored beverage wastewater into the adjustment tank,
Oxidizing agent adding means for adding an oxidizing agent to the colored drinking water drainage introduced into the adjusting tank and / or the adjusting tank;
A decolorizer for colored beverage wastewater, comprising: a catalyst tower into which effluent from the adjustment tank is introduced. The decolorizing apparatus for colored beverage wastewater according to claim 10, further comprising an activated carbon tower into which the effluent of the catalyst tower is introduced. The colored beverage wastewater decoloring apparatus according to claim 11, wherein the oxidizing agent is a chlorine-based oxidizing agent, and further comprising a measuring unit for measuring a residual chlorine concentration of the effluent of the catalyst tower. Decolorizer. 13. The decolorizing apparatus for colored beverage wastewater according to claim 10, further comprising a circulation line for returning a part of the effluent of the catalyst tower to the adjustment tank.

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