JP2004351306A - Water cleaning material effectively utilizing shell of foulings - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water cleaning material obtained by effectively utilizing shells of foulings such as mussels and barnacles being a waste from power generation plant. <P>SOLUTION: Shells of foulings being the waste from power generation plant are effectively utilized as contact material for water cleaning (filter material, microorganism carrier) and adsorbent for phophorus and nitrogen etc. Further, the shells of foulings with adsorbed phosphorus and nitrogen can be utilized as fertilizer and the effective waste utilizing technique of a resource recycling type is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a water purification material utilizing attached organism husks such as mussels and barnacles collected in a cooling water channel or the like of a power plant, a production method thereof, and uses thereof.
[0002]
[Prior art]
In order to prevent eutrophication of inner bays, lakes and dam lakes, it is necessary to reduce the load of nutrients through inflowing rivers and waterways. However, the tertiary treatment for removing nitrogen and phosphorus is costly. Further, nitrogen can be removed by a biological nitrification denitrification reaction, but phosphorus currently depends on a physicochemical method. In order to prevent eutrophication, wastewater treatment at a discharge source has become extremely important, and development of an economical and easy-to-handle water purification material has been desired.
[0003]
On the other hand, mussels and barnacles that adhere to and grow on the cooling water system of the power plant are periodically removed to reduce the cooling function and the like. These removed organisms have been incinerated or landfilled. However, there are problems such as shortage of disposal sites and generation of offensive odors when piled up, and it is urgently necessary to develop effective utilization measures.
[0004]
As an effective utilization measure, the use of husks as a raw material for cement has been partially performed. Although composting of shellfish has been attempted, it may not be accepted locally due to bad odors.
In recent years, a compound feed utilizing the mussels of mussels (Patent Document 1), and a method of separating and obtaining shells of soft shells using proteolytic enzymes and separating them from shells have been developed (Japanese Patent Application No. 2002-130881). No reference has been made on the effective use of shells for water purification materials.
[0005]
[Patent Document 1]
JP-A-11-28061
[Problems to be solved by the invention]
An object of the present invention is to develop a water purification material utilizing mussel shells and barnacle shells conventionally regarded as power station waste.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present inventor has conducted various studies on the effective use and treatment of the attached husks, and found that attached husks such as mussels such as mussels and barnacles such as red barnacles are used for water purification. The inventors have found that the present invention can be effectively used not only as a contact material (filter material, microbial carrier) but also as an adsorbent for phosphorus and the like, and thus completed the present invention.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In the cooling water channel of the power plant, seawater with a temperature several degrees higher than the surrounding sea area flows throughout the year. For this reason, a large number of attached organisms such as mussels, green mussels, barnacles, etc., having the appropriate water temperature, inhabit and propagate. These treatments are required for the power plant.
The present inventor paid attention to the fact that the attached husks are mainly composed of calcium carbonate, and conducted various studies on their effective use and treatment methods. As a result, the use as a contact material for water purification, alkali supply material, phosphoric acid phosphorus, etc. Of adsorbed husks as an adsorbent, effective use and reduced volume of attached husks by converting husks into fertilizer after nutrient adsorption, and also used as adsorbents (ion exchange materials) for ammonia nitrogen etc. I found what I can do. Hereinafter, a mussel is described as an example, but other attached biological hulls can be similarly used.
[0009]
[Preparation of shells]
The attached organism shell used for the contact material, the adsorbent and the like of the present invention is not particularly limited, but is preferably an attached organism shell in a cooling water channel of a power plant that grows under the same temperature conditions throughout the year. Blue mussels as attached organisms are removed from small ones of 1 cm or less to those of 10 cm or more in one cleaning of the cooling water channel. Shellfish is removed from such mussels for use. To remove the shell meat, open the shell with boiling water, or crush the shell partially, then decompose part or all of the shell meat using a protease such as papain, wash with water, screen, etc. To remove the shellfish.
Small shells are used as they are, and large shells are crushed to an appropriate size, and the particle size is adjusted according to the purpose before use. The shells are fired according to the purpose. The firing may be performed before or after the crushing of the shell, and may be performed in a normal firing furnace such as an electric furnace or an oil burner method. Although the firing temperature is not particularly limited, a temperature of 800 ° C. or higher is desirable in consideration of generation of dioxin and the like, and preferably around 800 to 900 ° C.
[0010]
[Contact material (water purification material)]
The attached husks can be used as a contact material for purification of circulating filtered water for fish farming and purification of domestic wastewater. As an example, utilization for circulating filtration fish farming will be described. In circulating filtration breeding, ammonia, which is the excrement of fish, is oxidized to low fish toxic nitric acid via nitrite by the action of microorganisms. In this action, the alkali in the water is consumed, so that the pH in the breeding water decreases. When the pH of the breeding water becomes 6 or less, the oxidation rate of ammonia is significantly reduced. For this reason, it is necessary to add sodium hydrogen carbonate or the like to keep the pH at about 7.
[0011]
When the mussel shell is used as a contact material with the breeding water, the ammonia oxidizing bacteria sufficiently propagate from a state in which almost no ammonia oxidizing microorganisms inhabit, and the water for about 60 days until the initial concentration of 50 mg / L of ammonia disappears from the water. The pH was kept between 7.5 and 7.9. . On the other hand, when a conventional plastic filter medium was used, it was necessary to add sodium hydrogen carbonate. The mussels of mussels, either fired or unfired, were crushed at the time of collection, and further crushed, showed similar results, and it was recognized that either type could be used. . It is preferably used unfired.
[0012]
Blue mussel shells are more suitable for the propagation of ammonia oxidizing bacteria than plastic filter media, and ammonia decreases faster than plastic filter media in a newly set aquarium.
The mussel shell can be used as a filter medium for a newly constructed circulation fish culture system (Japanese Patent Publication No. 7-55116, Japanese Patent No. 2035885). It is advisable to select the crushing particle size of the shell according to the amount of circulating water to be treated and the size of the filtration tank.
[0013]
For example, when the mussel shell was used as a contact material for circulating filtration rearing and the ammonia load per day was 4 to 5 mg / L, the shell weight was reduced by 30 to 40% after about 60 days. Therefore, when the attached hulls are used as a contact material for the oxidation of ammonia, the hulls serve as a source of alkali into water and can be subjected to shell volume reduction processing. Therefore, when the attached organism shell is used for river purification, etc., the calcium component of the shell returns to the original sea, and it is considered that a favorable result is also provided for environmental protection of marine organisms.
[0014]
[Phosphorus adsorption]
The mussel shell was found to have the property of adsorbing phosphoric acid-phosphorus even without treatment (unfired). In both cases of treated and untreated, the adsorption capacity of phosphorus is higher as the particle size of the shell is smaller. At a phosphate phosphorus concentration of about 10 mg / L, an adsorption rate of 90% or more within 24 hours for a particle diameter of less than 0.5 mm Having. In the case of a particle size of 0.5 to 1.0 mm, an adsorption rate of 50% is shown within 24 hours, and an adsorption rate of 65% is shown in 48 hours. Furthermore, the adsorption rate in one week (168 hours) is 85-90%. At a particle size of 1.0 mm or more and less than 10.0 mm, the adsorption rate is about 40% in 24 hours. Select the particle size according to the purpose of use.
[0015]
The phosphoric acid-phosphorus adsorbing ability of the mussel shell is increased by heat treatment. The heat treatment at about 100 to 200 ° C. does not change the adsorption ability of the untreated shell. Heat treatment at 400 to 600 ° C. is not preferable because it may increase the concentration of phosphoric acid phosphorus in the treated water. When treated (fired) at 800 to 900 ° C. for 1 hour, it has a shell shape and has an adsorption capacity of 90% or more for phosphoric acid phosphorus at a concentration of 100 mg / L within 24 hours. In the case of this heat treatment, shellfish may be present.
[0016]
From the viewpoint of handling, it is convenient and convenient to crush the mussel shell to an appropriate size, add a ceramic material such as clay to the mixture, mix and granulate, dry, and fire to obtain ceramic. The size of the crushed particles of the shell is not particularly limited, but a particle size of less than 0.5 mm is preferable from the viewpoint of mixability with clay and moldability. The mixing ratio with clay is preferably such that the amount of mussel shell fine powder is 50 to 60%. If the number of mussels is larger than this, shape retention may be deteriorated, and the shell may be damaged during use. The firing time is preferably about 800 to 900 ° C. for about 3 hours. After firing, cool in a furnace to room temperature. After that, it is stored in a closed container or immediately immersed in fresh water (preferably distilled water, but tap water is also acceptable), and then naturally dried, the strength is maintained and it is difficult to collapse. The phosphoric acid-phosphorus adsorbing ability of the ceramic shell is not different from that of the baked shell.
Although the size of the ceramic shell is not particularly limited, it is usually preferably about 5 to 10 mm in particle size, and if it is 5 cm or less, it can be used without any practical problem. The shape is usually granular, but may be various shapes such as a brick (brick) shape according to the purpose.
[0017]
The mussel husk used for the phosphoric acid phosphorus adsorption treatment can be further utilized as a phosphorus and calcium fertilizer. At present, Japan does not have phosphate ore resources and relies on imports of phosphorus fertilizers. ADVANTAGE OF THE INVENTION According to this invention, the mussel shell which adsorbed the phosphoric acid phosphorus can be used effectively as a fertilizer as well as a water quality purification material.
[0018]
[Ion exchange]
The mussel shells untreated and treated at 800 ° C. have no ability to adsorb ammonia nitrogen. However, when a very small amount of phosphoric acid phosphorus is added, the shell treated at 800 ° C. adsorbs ammonia nitrogen. This phenomenon is presumed to be adsorbed by ion exchange with calcium ions. Similarly, mussel shells adsorbing phosphoric acid phosphorus can be expected to adsorb metal ions such as cadmium, mercury, and lead by exchanging with calcium ions.
This ion exchange ability is not limited to the shell at the sintering temperature of 800 ° C., and the same effect can be obtained in shells baked at a temperature of 800 ° C. or higher.
Mussels of mussels adsorbing ammonia nitrogen by ion exchange can also be effectively used as fertilizer for green and farmland.
[0019]
【Example】
Hereinafter, the present invention will be described based on experimental examples, but the present invention is not limited to these examples.
[0020]
Experimental example 1
An experimental example using a mussel shell as a contact material is shown. Freshly prepared, ammonium chloride was added to a 10 L capacity water tank in which ammonia oxidizing bacteria did not inhabit so that the concentration of ammonia nitrogen was 50 mg / L, and 100 mL of plastic filter media was added to a small filtration tank. The treated mussel shell crushed pieces were put in, and an experiment was conducted by a circulation filtration method.
In the mussel shell, a decrease in the ammonia concentration was observed 20 days after the start of the experiment, and it became 0 mg / L on the 61st day. On the other hand, in the case of the plastic filter medium (EC filter medium), the oxidation of ammonia did not progress easily, and reached about 50% in 77 days. During this time, the pH of the plastic filter medium section dropped to 6, and 4 g of sodium hydrogen carbonate was added to maintain the pH. On the other hand, the pH of the mussel shell was maintained at 7.5 to 7.9. In addition, even in the blank section where no filter medium was added, ammonia oxidizing bacteria proliferated on the aquarium wall and the like, and a decrease in the ammonia concentration was observed. The results are shown in FIG.
[0021]
Experimental example 2
A 200-mL Erlenmeyer flask was charged with 100 mL of a 2 mg / L phosphoric acid-phosphorus solution and 10 g of untreated mussel shell having a particle size of less than 0.5 mm, and shaken at 65 rpm. As a result, as shown in FIG. 2, the phosphate phosphorus concentration after 24 hours was 0.1 mg / L.
[0022]
Experimental example 3
A 200 mL Erlenmeyer flask is charged with 100 mL of a 2 mg / L phosphoric acid-phosphorus solution, and 10 g of heat-treated mussel shell having a particle size of 0.5 to 1 mm and 10 g of an untreated shell having the same particle size as a control. And shaken at 65 rpm. The results were as shown in FIG. That is, the shells treated at 400 ° C. and 600 ° C. did not adsorb phosphorus, and sometimes the phosphorus concentration increased from the initial value. No difference was observed in phosphorus adsorption between the shells treated at 100 ° C. and 200 ° C. and untreated, and the adsorption rate after 24 hours was 50%. The phosphoric acid adsorption rate of the shell treated at 800 ° C. was 91%.
[0023]
Experimental example 4
In the same manner as in Experimental Examples 2 and 3, the phosphorus adsorption capacity of the shell pieces treated at 800 ° C. was examined for the size (0.5-1.0 mm, 1.0-10.0 mm, 10.0 mm or more). As a result, as shown in FIG. 4, no difference in the adsorption rate depending on the size was observed. In other words, if the treatment is performed at 800 ° C., the shell can be used as an adsorbent even in the same size.
[0024]
Experimental example 5
A ceramic (particle diameter: about 5 mm) produced by mixing and granulating mussel shell fine powder having a particle diameter of less than 0.5 mm and clay (60:40), drying and calcining the mixture was examined for phosphorus adsorption ability. The experiment method was the same as in Experiments 2, 3, and 4, 10 g of the ceramic was placed in an Erlenmeyer flask, and the initial concentration was 4 mg / L. The results are shown in FIG. The phosphoric acid phosphorus concentration after 14 hours was 1.5 mg / L, and after 24 hours was 0.17 mg / L, and the adsorption rate was 96%.
[0025]
Experimental example 6
A 200 mL Erlenmeyer flask was charged with 100 mL of a 12 mg / L ammonia-nitrogen solution, 10 g of mussel shell having a particle size of 0.5 to 1.0 mm heat-treated at 800 ° C. was placed therein, and the adsorption of ammonia was examined. As a result, as shown in FIG. 6, the reduction of ammonia did not occur until after 192 hours.
Therefore, 0.2 mL of a 155 μg / L phosphoric acid phosphorous solution was added. Twenty-four hours after the addition of the phosphoric acid phosphorus solution, a decrease in ammonia became evident, and after 48 hours (288 hours), 75% of ammonia nitrogen was adsorbed (see FIG. 6). The blank was similarly prepared using the same amount of mussel shell having a particle size of 0.5 to 1.0 mm without heat treatment.
[0026]
Experimental example 7
The phosphate concentration and the amount of phosphorus adsorbed per unit weight of the mussel shell treated at 800 ° C. and having a particle size of 0.5 to 1.0 mm were examined. As shown in FIG. 7, as the phosphoric acid concentration increased, the phosphorus adsorption amount also increased. At 96 mg / L, the adsorption amount was 0.85 mg / g. By using these values and relationships, the content of the fertilizer component can be calculated.
[0027]
【The invention's effect】
As described above, the present invention can utilize the attached biological hulls, which have been treated as power plant waste, as a water purification material such as a contact material, a phosphorus adsorbent, and an ion exchange material. The attached husks that have adsorbed phosphate phosphorus and ammonia nitrogen can be effectively used as phosphorus, nitrogen and calcium fertilizers.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between a filter medium and ammonia oxidizing ability.
FIG. 2 is a graph showing the phosphorus adsorption ability of mussels.
FIG. 3 is a graph showing the phosphorus adsorption capacity of heat-treated mussels.
FIG. 4 is a graph showing the relationship between the particle size of heat-treated mussels and the ability to adsorb phosphorus.
FIG. 5 is a graph showing the phosphorus adsorption ability of a mussel shell ceramic.
FIG. 6 is a graph showing the effect of adding phosphorus on the ammonia adsorption capacity of mussels.
FIG. 7 is a graph showing the relationship between phosphorus concentration and phosphorus adsorption capacity per unit weight of mussels.

Claims (5)

A water purification material characterized by using attached organism shells such as mussels such as mussels and barnacles such as red barnacles. Shellfish is removed from attached organisms such as mussels such as mussels and barnacles such as red barnacles. A method for producing a water purification material comprising: A ceramic water purification material that is composed of adherent husks as a main component, to which a ceramic material such as clay is added and fired. An ion-exchange material made from attached biological husks. Fertilizer made from attached biological husks that have absorbed nutrients.

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