JP2004141804A - Processing method and apparatus for aquatic organism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method of aquatic organisms capable of efficiently preventing the generation of putrefaction odor of aquatic organisms, requiring no addition of a separate coagulant by functioning a putrefaction odor preventing chemical as a coagulant in coagulation treatment of latter stage and realizing reduction of the cost for a putrefaction odor prevention countermeasure and the processing cost and simplification of the processing, and an apparatus. <P>SOLUTION: The processing method and the apparatus for aquatic organisms are characterized in that an iron salt is added to an aquatic organism landed and primarily stored and the pH is adjusted to an acidic side, the iron salt is dissolved and functioned as the putrefaction odor prevention chemical for the aquatic organism, the pH is adjusted to a neutral side in the coagulation treatment of the latter stage and the dissolved iron salt is precipitated as iron hydroxide, thereby it is functioned as the coagulant. <P>COPYRIGHT: (C)2004,JPO

Description

【００３３】
上記試験結果から明らかなように、薬剤添加無しでは硫化水素濃度は経過時間とともに著しく増加するが、硫酸第二鉄、塩化第二鉄を添加したサンプルについては、添加濃度１０００ｐｐｍ〜２０００ｐｐｍの検体で硫化水素濃度は検出下限以下（ＮＤ、０．０２ｐｐｍ以下）であり、極めて優れた腐敗臭防止効果が確認された。
【００３４】
【発明の効果】
以上説明したように、本発明に係る水生生物の処理方法および装置によれば、一次貯留された水生生物に対し鉄塩を添加するとともにｐＨを酸側に調整し、鉄塩を溶解させて水生生物の腐敗臭防止薬剤として機能させ、後段の凝集処理においては、ｐＨを中性側に調整し、溶解された鉄塩を水酸化鉄として析出させることにより凝集剤として機能させるようにし、初期に添加した薬剤に２つの機能を発揮させるようにしたので、別途凝集剤を大量に添加することは不要になり、処理費用の低減、処理の簡素化を達成できるとともに、実施例に示したように優れた腐敗臭防止効果を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施態様に係る水生生物の処理装置の機器系統図である。
【図２】アルミニウムと第二鉄のｐＨに対する溶解特性図である。
【符号の説明】
１　一次貯留槽
２　腐敗臭防止薬剤添加手段
３　ｐＨ計
４　ポンプ
５　貯留槽循環移送ポンプ
６　原水槽
７　ポンプ
８　流量調整装置
９　ｐＨ調整槽としての反応槽
１０　ｐＨ計
１１　ｐＨ調整剤添加手段
１２　ポンプ
１３　凝集槽
１４　凝集助剤添加手段
１５　ポンプ
１６　浮上分離槽
１７　加圧槽
１８　コンプレッサ
１９　汚泥槽
２０　ポンプ
２１　脱水機
２２　脱水汚泥
２３　乾燥機（減圧乾燥機）
２４　乾燥汚泥
２５　リターンライン
２６　処理水槽
２７　ポンプ
２８　ろ過装置
２９　ＣＯＤ除去装置としてのＣＯＤ吸着塔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for treating aquatic organisms such as jellyfish, and in particular, can efficiently treat marine organisms such as jellyfish that have been removed and recovered in an intake channel that takes in a large amount of seawater as cooling water. The present invention relates to a method and an apparatus for treating aquatic organisms.
[0002]
[Prior art]
In seaside plants such as power plants, a large amount of seawater is used as cooling water, and marine organisms (aquatic organisms) such as jellyfish enter this seawater intake channel. If these marine organisms are left untreated, the intake channels will be blocked and the amount of cooling water withdrawn will be reduced, leading to a reduction in the cooling efficiency of the plant. Furthermore, it also leads to failure of plant equipment, lowering of the operation rate, and eventually to shutdown of the power plant, causing various adverse effects. In such a seaside plant, for the purpose of protecting the plant from various adverse effects, a screen is provided in an intake channel, and aquatic organisms mixed with seawater are captured in the intake channel, landed, removed, collected and disposed of.
[0003]
Aquatic organisms, such as jellyfish, have been sun-dried and buried underground after being landed and recovered.However, the rotten odor mainly due to hydrogen sulfide is severe, and the working environment and There was a problem in the surrounding environment.
[0004]
As a countermeasure against this problem, there has been known a technique for suppressing a putrefaction odor generated from aquatic organisms such as jellyfish by adding an aluminum sulfate salt as a countermeasure against putrefaction odor (for example, Patent Document 1). There is also known a treatment technique for reducing the volume of landed aquatic organisms such as jellyfish by adding a foam solidifying agent (for example, Patent Document 2).
[0005]
[Patent Document 1]
JP 2001-122713 A (Claims)
[Patent Document 2]
JP 2002-45838A (Claims)
[0006]
[Problems to be solved by the invention]
However, in the method of adding an aluminum sulfate salt as described above as a countermeasure against putrefaction odor, although the aluminum sulfate salt itself has an effect of suppressing putrefaction odor, it is difficult to exert a function as a coagulant. In a coagulation treatment step usually provided at a later stage, a large amount of a coagulant must be separately added, which causes an increase in treatment cost and complication of the treatment.
[0007]
An object of the present invention is to add a flocculant separately so as to efficiently prevent the generation of putrefactive odor of aquatic organisms and to allow the putrefaction odor preventing agent to function also as a flocculant in the subsequent flocculation treatment. It is an object of the present invention to provide a method and an apparatus for treating aquatic organisms, which can be made unnecessary, and can achieve both a countermeasure against putrefaction odor, a reduction in treatment cost, and simplification of treatment.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the method for treating aquatic organisms according to the present invention comprises adding an iron salt to the aquatic organisms that have been landed and temporarily stored, adjusting the pH to the acid side, and dissolving the iron salt. It functions as an aquatic organism's putrefaction odor preventing agent, and in the subsequent coagulation treatment, adjusts the pH to a neutral side, and functions as a coagulant by precipitating the dissolved iron salt as iron hydroxide. The method consists of: As the iron salt, a ferric salt, in particular, ferric sulfate or ferric chloride can be added.
[0009]
That is, in the present invention, an iron salt (ferric sulfate, ferric chloride) as an easily handled agent generally used as a water treatment agent is dissolved and brought into contact with aquatic organisms such as jellyfish. This effectively suppresses the generation of hydrogen sulfide, which is a cause of putrefaction odor of aquatic organisms such as jellyfish. In particular, for aquatic organisms such as jellyfish collected in a cooling water intake channel of a power plant or the like, hydrogen sulfide or the like, which is a kind of putrefactive odor, can be remarkably suppressed by adding the above-mentioned chemical agent in an amount of 500 to 2000 ppm. Measures can be taken to prevent putrefaction odor. This dissolved ionic iron salt can be precipitated as iron hydroxide by adjusting the pH to a neutral side in the subsequent coagulation treatment, and the precipitated iron hydroxide functions as a coagulant. Can be done. Therefore, the iron salt that was first added as an aquatic organism putrefaction odor prevention agent can be converted into iron hydroxide in the subsequent stage and used as a flocculant, eliminating the need to separately add a large amount of a flocculant, thereby reducing processing costs and processing. Simplification is achieved.
[0010]
As described above, conventionally, the treatment after recovery of aquatic organisms such as jellyfish requires manipulation of the object with a violent putrefaction odor, but the addition of an iron salt can significantly suppress the putrefaction odor peculiar to aquatic organisms. In addition, the working environment and surrounding environment of the processing work can be improved, and the working efficiency can be improved. Further, the effect of adding the chemical solution is maintained for one month or more as shown in the examples described below, and even when a large amount of aquatic organisms such as jellyfish are irregularly generated in large amounts, the recovery and processing operations are planned. Implementation becomes possible.
[0011]
In this chemical injection control, by controlling the pH instead of the concentration control, it is possible to easily prevent the spoilage of aquatic organisms such as jellyfish that are unsteadily landed. The pH control value is preferably adjusted to 4 or less, particularly preferably 2 to 4. By this pH control, it is possible to control the iron salt concentration corresponding thereto. When the iron salt is ferric sulfate, the concentration can be controlled at about 1000 to 2000 ppm, and when the iron salt is ferric chloride, the concentration can be controlled at about 500 to 2000 ppm. Particularly when ferric chloride was used, it was confirmed that the addition of a chemical solution of 500 ppm was somewhat inferior in the effect of preventing putrefaction odor. It can be controlled to about 2,000 ppm, whereby a sufficient putrefaction odor prevention effect can be obtained.
[0012]
In the coagulation treatment, by adding a coagulation aid together with an alkali for adjusting the pH to a neutral side, the growth of coagulated flocs can be promoted, and a more rapid and effective coagulation treatment can be performed. As the coagulation aid, a polymer coagulant or the like can be used, and it is usually sufficient to add a small amount.
[0013]
The treatment apparatus for aquatic organisms according to the present invention is a treatment apparatus for treating aquatic organisms having a storage tank for temporarily storing landed aquatic organisms, and a means for adding an aquatic organism putrefaction odor preventing agent to the primary storage tank. It is characterized in that an iron salt is used as the putrefaction odor preventing agent. As the iron salt, a ferric salt, in particular, ferric sulfate or ferric chloride can be used.
[0014]
The addition amount of the putrefaction odor preventing agent by the putrefaction odor preventing agent adding means can be controlled based on a detection value of a pH meter attached to the primary storage tank. It is preferable that the amount of the putrefaction odor preventive agent is controlled to be pH 4 or less.
[0015]
The aquatic organisms stored in the primary storage tank can be crushed into small pieces by the storage tank circulation transfer pump, transferred to the post-processing system together with the contained water, and partially circulated. The post-treatment system is provided with a coagulation tank using iron hydroxide precipitated from the iron salt as a coagulant. A raw water tank may be provided between the primary storage tank and the flocculation tank to temporarily store the objects to be treated (crushed aquatic organisms and contained water) transferred by the storage tank circulation transfer pump.
[0016]
At the time of the coagulation treatment, the dissolved ionic iron salt is precipitated as iron hydroxide so that it can be used as a coagulant. For example, it is necessary to adjust the pH to a neutral side by adding NaOH). The pH adjusting tank for this purpose may be provided integrally with the coagulation tank, or may be provided as an adjacent reaction tank. It is preferable that a pH meter is installed in the pH adjusting tank, and an automatic chemical injection device that adjusts an alkali addition amount based on a measured value of the pH meter is provided. Further, it is preferable that a coagulation auxiliary agent adding means is provided in the coagulation tank.
[0017]
A flotation tank that floats and separates flocculated flocs in the water to be treated from the flocculation tank using pressurized water can be provided at the subsequent stage of the flocculation tank. The gas (air) dissolved in the pressurized water that has been sent is released in the flotation tank to become microbubbles, and as the microbubbles float, the flocculated flocs float, and the flocculated flocs and the treated water are separated. Is separated into As the pressurized water sent to the pressurized flotation tank, fresh water typified by industrial water, or seawater, or treated water of a filtration device described later, or treated water of a COD removal device can be used. After pressurizing using a compressor in a pressure tank, the solution may be sent to a flotation tank.
[0018]
To the flotation tank, a dehydrator for collecting aquatic organism flocculated flocs separated by flotation by a pre-installed scraping device, removing the floc from the flotation tank, and performing a dehydration treatment can be connected. The treated water separated by the dehydrator can be returned to the primary storage tank. By returning the waste liquid dehydrated by the dehydrator to the primary storage tank, the system can be configured without adding a wastewater treatment device generated from the dehydrator.
[0019]
Alternatively, a drier for dehydrating the aquatic organism flocculent separated by flotation, in particular, a vacuum drier can be connected to the flotation tank. By treating with a reduced-pressure drier, the water content of sludge can be extremely reduced without generating excess waste liquid, and the final sludge treatment operation can be simplified.
[0020]
In addition, the flotation tank can be connected to a filtration device for removing suspended substances in the flotation treatment water. The filtration device is not particularly limited, and a sand filtration device or a membrane filtration device can be used. When a membrane filtration device is used, it is preferable to use a relatively coarse filter so that clogging does not occur in a short time. As the membrane filter applied to the membrane filtration device, a hollow fiber membrane filter, a pleated membrane filter, and the like can be applied. Among them, a non-backwash type pleated filter that does not require a backwash regeneration facility is preferable. The aperture of the filter can be selected from about several μm to several tens μm, and can be appropriately selected from the measurement results of the particle size distribution of the water to be treated. By applying a non-backwash type filter, the equipment can be made compact.
[0021]
A COD removal device that removes a COD component in the flotation water from which suspended substances have been removed can be connected to the filtration device. The COD removal device can be configured as, for example, a COD adsorption tower using activated carbon.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an apparatus for treating aquatic organisms according to an embodiment of the present invention. In FIG. 1, landed aquatic organisms (eg, jellyfish) are stored in a primary storage tank 1 from a trash pit. An iron salt is added to the primary stored aquatic organisms from the putrefaction odor preventing agent adding means 2 as a putrefaction odor preventing agent. This addition amount is controlled by a pump 4 capable of controlling the feed amount based on a detection value of a pH meter 3 attached to the primary storage tank 1. When the iron salt is ferric sulfate, the amount of addition is controlled, for example, to a pH of 2 to 4, whereby the amount of addition is controlled in the range of about 1000 to 2000 ppm. When the iron salt is ferric chloride, the pH is controlled, for example, to be 2 to 2.5, whereby the amount of addition is controlled in the range of about 1000 to 2000 ppm. When the inside of the primary storage tank 1 is adjusted to such an acid-side pH, the iron salt dissolves and becomes ionic, and functions as a putrefaction odor preventing agent.
[0023]
The primary storage tank 1 is provided with a storage tank circulation transfer pump 5 (P1), and the aquatic organisms stored in the primary storage tank 1 are crushed into small pieces by the storage tank circulation transfer pump 5 and contained water. , And is transferred to a post-processing system, part of which is circulated. In this embodiment, the aquatic organisms and the contained water crushed into small pieces from the primary storage tank 1 are temporarily stored in the raw water tank 6.
[0024]
The aquatic organisms and the water contained in the raw water tank 6 are sent to a reaction tank 9 as a pH adjusting tank by a pump 7 (P2) via an appropriate flow rate adjusting device 8 such as an overflow weir. The reaction tank 9 is provided with a pH meter 10, and based on the detected value of the pH meter 10, the amount of the pH adjuster (for example, NaOH) from the adding means 11 is controlled by the feed amount of the pump 12. . By adding a pH adjuster, the pH is adjusted to a neutral side (for example, about 6 to 7), whereby the dissolved iron salt is precipitated as iron hydroxide and functions as a flocculant. In the present embodiment, a coagulation tank 13 is provided adjacent to the reaction tank 9. The coagulation tank 13 is provided with a coagulation aid adding means 14 made of a polymer coagulant or the like, and a small amount of coagulation aid is added by a pump 15. The addition of the coagulation aid promotes the growth of the flocculated floc, and the flocculation tank 13 quickly generates the flocculated floc of a desired size.
[0025]
The water to be treated from the coagulation tank 13 is sent to the flotation tank 16. During or during the supply to the flotation tank 16, pressurized water in which air is dissolved is supplied, and the pressurized water is released to the atmospheric pressure, so that the dissolved air is converted into fine bubbles. Then, the bubbles merge with the flocculated flocs, the flocculated flocs float, and as the bubbles float, they are separated into flocculated flocs (sludge) and treated water. For the generation of pressurized water, industrial water, seawater, treated water in the present system (for example, treated water of a filtration device described later), or the like can be used.
[0026]
The sludge from the flotation tank 16 is stored in, for example, a sludge tank 19, from which it is sent to a dehydrator 21 by a pump 20. The sludge 22 dehydrated by the dehydrator 21 is used for disposal, burying, and the like. Alternatively, the sludge from the sludge tank 19 may be sent to a dryer 23 (for example, a reduced-pressure dryer) and processed into a dried sludge 24. The dewatered treated water from the dehydrator 21 is returned to the primary storage tank 1 via the return line 25. When the dried sludge 24 is formed by the dryer 23, condensed water of evaporated water is obtained. However, since the condensed water is basically distilled water, water that requires further treatment is basically generated. No, the processing becomes easier. For example, dry sludge 24 can be subjected to processing such as bagging as dry powder.
[0027]
In the present embodiment, the treated water from the flotation tank 16 is temporarily stored in a treated water tank 26, and then sent to a filtration device 28 via a pump 27. In the filtration device 28, suspended matter in the flotation treatment water is removed. A COD adsorption tower 29 filled with activated carbon as a COD removal device is provided at the subsequent stage of the filtration device 28, and the COD components in the flotation treatment water from which suspended substances have been removed by the filtration device 28 are adsorbed and removed. . Part of the treated water of the filtration device 28 is sent to the above-mentioned pressurized tank 17 and used as pressurized water generation water. The treated water from the COD adsorption tower 29 is substantially the final treated water in the present system.
[0028]
In the system as described above, the iron salt added to the primary storage tank 1 is dissolved in the acid range at a predetermined pH and functions as an aquatic organism's putrefaction odor preventing agent. By adjusting the pH and precipitating as iron hydroxide, it functions as a flocculant. In other words, the initially added drug exerts a different function in each step, eliminating the need for a coagulant conventionally added in large quantities, reducing processing costs and simplifying the processing as a whole. You. In addition, as shown in the test results described later, an excellent effect of preventing putrefaction odor is ensured.
[0029]
Thus, the advantage of using an iron salt as a putrefaction odor preventing agent in the present invention also has the following points. That is, when an aluminum-based agent is used as in the above-mentioned Patent Document 1, it is practical to use the agent so as to exhibit both functions of the putrefaction odor preventing agent and the coagulant as described above. Have difficulty. As shown in FIG. 2, which shows general characteristics, the dissolution characteristics of aluminum (Al) exhibit extremely sharp characteristics with a narrow bottom at the characteristic curve. Is virtually impossible. However, the dissolution characteristic of ferric iron (Fe) is such that the bottom of the characteristic curve exhibits an extremely broad characteristic and the bottom of the broad characteristic curve is widely spread around pH 7 to 8. By adjusting the pH to a neutral side, it is possible to easily control the precipitation as iron hydroxide that is difficult to dissolve or that does not dissolve to function as a flocculant. Thus, the use of iron salts, particularly ferric salts, in the present invention has a special significance.
[0030]
【Example】
The following test was conducted on the effect of preventing putrefaction odor represented by hydrogen sulfide when the iron salt was added as a putrefaction odor preventing agent in the above system.
[0031]
Moon jellyfish was sampled from the sea area as one of aquatic organisms, and the sample was weighed and sampled in a 1000 ml polyvine to 500 ml. Ferric sulfate or ferric chloride was added to the polyvin, the polyvin was sealed, and the temporal change of the concentration of hydrogen sulfide in the gas phase was measured in an atmosphere at 30 ° C. to 35 ° C. Table 1 shows the hydrogen sulfide concentration measurement results.
[0032]
[Table 1]

[0033]
As is clear from the above test results, the hydrogen sulfide concentration increases significantly with the lapse of time without the addition of the chemical, but for the samples to which ferric sulfate and ferric chloride were added, the sulfuric acid concentration was 1000 ppm to 2000 ppm for the sample. The hydrogen concentration was below the lower limit of detection (ND, 0.02 ppm or less), and an extremely excellent putrefaction odor prevention effect was confirmed.
[0034]
【The invention's effect】
As described above, according to the method and apparatus for treating aquatic organisms according to the present invention, the iron salt is added to the primary stored aquatic organisms, the pH is adjusted to the acid side, the iron salt is dissolved, and the aquatic organism is dissolved. In order to function as an agent for preventing the putrefaction odor of organisms, in the subsequent coagulation treatment, the pH is adjusted to the neutral side, and the dissolved iron salt is precipitated as iron hydroxide to function as a coagulant. Since the added drug is made to perform two functions, it is not necessary to separately add a large amount of a coagulant, and it is possible to achieve a reduction in processing cost and simplification of processing, as shown in the examples. Excellent rotting odor prevention effect can be obtained.
[Brief description of the drawings]
FIG. 1 is an equipment system diagram of an apparatus for treating aquatic organisms according to an embodiment of the present invention.
FIG. 2 is a graph showing dissolution characteristics of aluminum and ferric iron with respect to pH.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Primary storage tank 2 Putrefactive odor prevention chemical addition means 3 pH meter 4 Pump 5 Storage tank circulation transfer pump 6 Raw water tank 7 Pump 8 Flow rate control device 9 Reaction tank as pH adjustment tank 10 pH meter 11 pH adjuster addition means 12 Pump 13 Coagulation tank 14 Coagulation aid addition means 15 Pump 16 Floatation separation tank 17 Pressurization tank 18 Compressor 19 Sludge tank 20 Pump 21 Dehydrator 22 Dewatered sludge 23 Dryer (decompression dryer)
24 Dry sludge 25 Return line 26 Treated water tank 27 Pump 28 Filtration device 29 COD adsorption tower as COD removal device

Claims (21)

Iron salts are added to the aquatic organisms that have been landed and primarily stored, and the pH is adjusted to the acid side.The iron salts are dissolved to function as an aquatic organism's putrefaction odor preventing agent. A method for treating aquatic organisms, which is adjusted to a neutral side and functions as a flocculant by precipitating the dissolved iron salt as iron hydroxide. The method for treating aquatic organisms according to claim 1, wherein a ferric salt is added as the iron salt. The method for treating aquatic organisms according to claim 2, wherein the ferric salt is ferric sulfate or ferric chloride. The method for treating an aquatic organism according to claim 1, wherein the pH is adjusted to 4 or less by adjusting the amount of the iron salt added to the aquatic organism. The method for treating an aquatic organism according to claim 1, wherein a coagulation aid is added in the coagulation treatment. In an aquatic organism treatment device having a storage tank for temporarily storing landed aquatic organisms, and a means for adding an aquatic organism putrefaction odor preventing agent to the primary storage tank, an iron salt is used as the putrefaction odor preventing agent. An aquatic organism treatment device characterized by the above-mentioned. The aquatic organism treatment device according to claim 6, wherein the amount of the putrefaction odor preventing agent added by the putrefaction odor preventing agent adding means is controlled based on a detection value of a pH meter attached to the primary storage tank. The aquatic organism treatment device according to claim 7, wherein the amount of the putrefaction odor preventing agent is controlled to be pH 4 or less. The storage tank circulation transfer pump which crushes the aquatic organisms stored in the primary storage tank into small pieces, transfers the crushed water to the post-processing system together with the contained water, and circulates a part of the storage tank, is provided. An aquatic organism treatment device according to claim 1. The aquatic organism treatment device according to claim 9, wherein the post-treatment system is provided with a coagulation tank using iron hydroxide precipitated from the iron salt as a coagulant. The aquatic organism treatment device according to claim 10, wherein a pH adjusting tank for precipitating iron hydroxide from the iron salt is provided integrally with or adjacent to the flocculation tank. The aquatic organism treatment device according to claim 10 or 11, wherein a coagulation aid adding means is provided to the coagulation tank. The aquatic organism treatment device according to any one of claims 6 to 12, wherein a ferric salt is used as the iron salt. 14. The aquatic organism treatment device according to claim 13, wherein the ferric salt comprises ferric sulfate or ferric chloride. The treatment of aquatic organisms according to any one of claims 10 to 14, wherein a flotation tank that floats and separates flocculated floc in the water to be treated from the flocculation tank using pressurized water is provided at a stage subsequent to the flocculation tank. apparatus. The aquatic organism treatment device according to claim 15, wherein a dehydrator for dehydrating the aquatic organism flocculent separated by the flotation is connected to the flotation tank. 17. The aquatic organism treatment apparatus according to claim 16, further comprising a line for returning the treated water separated by the dehydrator to a primary storage tank. The aquatic organism treatment device according to claim 15, wherein a vacuum dryer for dehydrating the aquatic organism flocculent separated by flotation is connected to the flotation tank. The aquatic organism treatment device according to claim 15, wherein a filtration device for removing suspended substances in the flotation treatment water is connected to the flotation tank. The aquatic organism treatment device according to claim 19, wherein a COD removal device that removes a COD component in the flotation treatment water from which suspended substances have been removed is connected to the filtration device. 21. The aquatic organism treatment device according to claim 20, wherein activated CO is used in the COD removal device.

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