JP5492335B1 - Method for producing flocculant and flocculant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a flocculant overcoming the drawbacks of an aluminum sulfate solution using an aluminum sulfate solution as a raw material, and a flocculant.
[MEANS FOR SOLVING PROBLEMS] Shell water and calcium carbonate as a coagulant aid are put into pure water stored in a first tank, and they are sufficiently stirred and mixed by a stirrer. After the shellfish powder and calcium carbonate are dissolved by adding an aluminum sulfate solution (preferably a sulfuric acid sulfate) from the second tank into the first tank and stirring vigorously, the stirrer installed in the first tank is stopped. Then, the mixture is allowed to stand for a suitable time for gelation (step S30). Then, dilute hydrochloric acid is added from the third tank to the first tank to re-dissolve the gel (step S40).
[Selection] Figure 1

Description

  TECHNICAL FIELD The present invention relates to a method for producing a flocculant for water treatment such as industrial wastewater / water or water and sewage, and a flocculant.

  Water purification plants mainly purify the water taken from the river and supply it to the waterworks, but in the upstream process when purifying, add flocculant to the raw water taken from the river to agglomerate the pollutants in the raw water It has been removed. In such a water purification plant, an aluminum flocculant solution or a polyaluminum chloride solution, which is an inorganic flocculant, is used as the flocculant.

  On the other hand, Patent Document 1 described below discloses a solid flocculant containing at least one substance selected from a cellulose fiber material, a shell, and a solid auxiliary agent in an organic flocculant and an inorganic flocculant. In such a solid flocculant, since the desired flocculant action continues continuously for a long time, a large amount of contaminated water can be clarified with a small amount of flocculant.

Japanese Patent Laid-Open No. 6-99008

However, the conventional flocculants described above have the following problems.
That is, the polyaluminum chloride solution has a wider range of applicable pH than the aluminum sulfate solution, has a strong agglomeration effect, and the strength of the floc formed is high, so the amount added can be relatively reduced. The former flocculant has the disadvantage that it has a weaker cohesion with respect to humic substances caused by corrosion of organic substances than the latter flocculant, although it is excellent in that it can be produced.

  On the other hand, since the flocculant disclosed in Patent Document 1 is a solid type, it takes a long time and labor to dissolve in raw water, and when a relatively large amount of raw water is treated at once, the whole is uniformly distributed. It was difficult to make. Therefore, it was not possible to sufficiently form the floc.

  The present invention has been made in view of such circumstances, and a method of producing an aggregating agent that overcomes the drawbacks of an aluminum sulfate solution while using the aluminum sulfate solution as a raw material while leaving the above-described advantages, and the method. A manufactured flocculant is provided.

  (1) The method for producing a flocculant according to the present invention is a solution-solidifying step in which when a flocculant containing an inorganic flocculant is to be used for water treatment, a predetermined shellfish shell powder is dissolved in an aluminum sulfate solution and gelled. And a redissolving step in which hydrochloric acid is added to the obtained gel and redissolved.

  In the method for producing a flocculant of the present invention, when producing a flocculant containing an inorganic flocculant for use in water treatment, a dissolution and solidification step in which a predetermined shellfish powder is dissolved in an aluminum sulfate solution and gelled is performed. carry out. As shellfish to be applied to shellfish powder, bivalves, clams, snails, etc., are not specified, but oysters, scallop shells (red shellfish), scallops, etc. It is suitable from the viewpoint of waste utilization and stable supply.

  As a result of intensive studies by the present inventors, such shellfish powder is dissolved in an aluminum sulfate solution, all of them are gelled, and hydrochloric acid is added to the resulting gel to re-dissolve it, so that the cohesive force is high and stable. As a result, the inventors have obtained the knowledge that a liquid flocculant that can be stored can be obtained, thereby completing the present invention. At this time, even if the shell powder can be dissolved in the aluminum sulfate solution, if it cannot be sufficiently gelled, the required cohesive force cannot be obtained even if it is re-dissolved in the re-dissolution step. .

  That is, shellfish powder contains proteins and polysaccharides in addition to calcium carbonate, which is the main component thereof, and these proteins and polysaccharides act as a crosslinking agent, and carbonate ions and aluminum sulfate solution generated from shellfish powder. It is considered that the gel is generated by the interaction with the aluminum ions in the solution and the interaction between the calcium ions generated from the shellfish powder and the sulfate ions in the aluminum sulfate solution. And it is thought that the mixed-like solution of aluminum chloride and aluminum sulfate is produced | generated by adding hydrochloric acid to the produced | generated gel and making it redissolve.

  At this time, since hydrochloric acid not containing aluminum ions exhibiting the coagulation ability is added, the concentration of aluminum ions is lowered by the amount of hydrochloric acid added, and the cohesive force per unit amount is also lowered accordingly. However, since calcium ions produced from shellfish powder also have a coagulation ability, the decrease in cohesion due to the decrease in the concentration of aluminum ions can be offset by the addition of calcium ions.

  The flocculant produced by such a method has the characteristics of both a polyaluminum chloride solution and an aluminum sulfate solution, which are conventional flocculants. Thus, in the method according to the present invention, an aggregating agent that overcomes the drawbacks of an aluminum sulfate solution can be produced using an aluminum sulfate solution as a raw material while retaining the advantages of a polyaluminum chloride solution.

  (2) Moreover, the manufacturing method of the flocculant which concerns on this invention adds the aluminum sulfate solution to this, suspending shellfish powder in water and stirring the obtained suspension water in the said solution solidification process. It is characterized by dissolving shellfish powder.

  In the method for producing a flocculant of the present invention, the shell powder is uniformly dispersed in water by suspending the shell powder in water and stirring the obtained suspension water in the above-described dissolution and solidification step. In this state, by adding the aluminum sulfate solution to the suspension water, the shell powder can be dissolved almost uniformly without any bias in the entire suspension water.

  In the production process, the aforementioned gel is composed of proteins and polysaccharides produced from shell powder, carbonate ions produced from shell powder and aluminum ions in aluminum sulfate solution, and calcium ions and aluminum sulfate produced from shell powder. It is important that each sulfate ion in the solution is balanced, but as mentioned above, the shell powder can be dissolved almost uniformly in the whole suspension water, so that the shell powder is kept in such a balanced state. Can be dissolved. As a result, the entire amount of the suspended water is gelled.

  (3) On the other hand, the method for producing a flocculant according to the present invention is characterized by using a sulfuric sulfate as the aluminum sulfate solution.

  In the method for producing a flocculant according to the present invention, sulfate sulfate is used as the aluminum sulfate solution. Sulfur sulfate is already on the market to produce drinking water, and its safety has also been confirmed. The flocculant produced by dissolving the shellfish powder, which is a natural product, in such sulfate sulfate is excellent in safety and can suppress the increase in the burden on the natural world as much as possible.

  (4) By the way, in the method for producing a flocculant according to the present invention, the shell powder is suspended in water in the dissolution and solidification step, and the obtained suspension water is stirred, and an aluminum sulfate solution is added thereto as a sulfate sulfate. Is added to dissolve the shell powder, and the mass ratio of water: shell powder: sulfate sulfate is adjusted to 25: 10-15: 50-70.

  In the method for producing the flocculant of the present invention, in the dissolution and solidification step, the shellfish powder is suspended in water, and the resulting suspension water is stirred, while adding sulfuric sulfate as an aluminum sulfate solution thereto. In dissolving the shell powder, the mass ratio of water: shell powder: sulfate is adjusted to 25: 10-15: 50-70. If the mass ratio of water: shell powder: sulfuric acid is not within these ranges, the shell powder cannot be dissolved while maintaining the balance as described above, and therefore the required cohesive force cannot be obtained. In contrast, when the mass ratio of water: shell powder: sulfuric acid is within these ranges, the shell powder can be dissolved in a balanced state, and the required cohesive force can be obtained. It can be stored stably.

Furthermore, (1) is characterized in that 5% by mass or more and 10% by mass or less of dilute hydrochloric acid is used in the re-dissolution step.

  In the method for producing the flocculant of the present invention, since 5% by mass or more and 10% by mass or less of dilute hydrochloric acid is used in the re-dissolution step, carbonate ions, calcium ions, aluminum ions, sulfate ions, and chloride ions are used. The gel can be redissolved while maintaining balance. As a result, it is possible to avoid a decrease in cohesive force and to store stably.

In the above (1), the shell powder is prepared by pulverizing shells dried in an environment of a temperature or lower as appropriate.

  In the method for producing a flocculant of the present invention, shellfish powder is prepared by pulverizing a shellfish dried in an environment of a temperature or lower as appropriate. Specifically, those which are naturally dried or dried at a temperature of about 80 ° C. or lower are used. Thereby, crushing by a vibration mill can be easily performed, and it can be dissolved smoothly in the dissolution and solidification step, which is preferable. On the other hand, the fired shell is not suitable as a raw material in the dissolution and solidification process. This is because the necessary active ingredients described above are decomposed by heat.

(5) In addition, the production method of the flocculant according to the present invention, the Te dissolved solidifying step smell, calcium to aluminum sulfate solution carbonate, dissolving in a weight ratio of 1-5 relative to the shell powder 10-15 It is characterized by.

In the method for producing a flocculant of the present invention, an appropriate amount of calcium carbonate is also dissolved in the aluminum sulfate solution in the dissolution and solidification step. Specifically, when the mass ratio of water: shell powder: sulfate sulfate is 25: 10-15 : 50-70, the calcium carbonate is dissolved so as to have a mass ratio of 1-5 . Thereby, the cohesive force of the coagulant can be adjusted to a required level.

(6) The flocculant according to the present invention is a flocculant containing an inorganic flocculant for use in water treatment, and is produced by the production method according to any one of (1) to (5). Features.

Since the flocculant of the present invention is manufactured by the manufacturing method according to any one of (1) to (5) , the above-described effects are exhibited.

It is a flowchart which shows the manufacture procedure of the coagulant | flocculant which concerns on this invention. It is a graph which shows the result of having compared the coagulation effect with respect to the artificial sewage of low turbidity. It is a graph which shows the result of having compared the aggregation effect with respect to the artificial sewage of medium turbidity. It is a graph which shows the result of having compared the aggregation effect with respect to artificial sewage of high turbidity. It is a graph which shows the result of having compared the aggregation effect with respect to natural sewage. It is a graph which shows the result compared about the influence which the temperature of to-be-processed water has on cohesiveness. It is a graph which shows the result of having examined about the influence which pH of to-be-processed water has on the aggregation effect of a flocculant. It is a graph which shows the result compared about the influence which the alkalinity of to-be-processed water has on the aggregation effect of a flocculant. It is a graph which shows the result compared about the influence which the usage-amount of a flocculant has on the pH of to-be-processed water.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the matter described in the present embodiment is an example for explaining the gist of the present invention, and it is needless to say that the present invention includes modifications or alterations without departing from the gist of the present invention.

  FIG. 1 is a flowchart showing a procedure for producing a flocculant according to the present invention.

As shown in FIG. 1, a crushing process is performed (step S10).
That is, the raw material shell is filled in the hopper, and the raw material shell is charged into the vibration mill from the hopper with a belt conveyor until an appropriate amount is obtained.

  Here, as for the shells applied to the raw material shells, the types of clams, clams, snails, etc. are not particularly specified, but oysters, scallop shells (red shellfish), scallops, etc., which are discarded in a relatively large amount by aquaculture Is preferable from the viewpoint of waste utilization and stable supply. The raw material shell may be undried, but when it is naturally dried or dried at a low temperature of about 80 ° C. or less, it can be easily crushed by a vibration mill, and the dissolution described later This is suitable because it can be dissolved smoothly in the solidification step. However, the fired shell is not suitable as a raw material in the dissolution and solidification process. This is because the required active ingredient is decomposed by heat.

  When an appropriate amount of the raw material shell is put into the vibration mill, the vibration mill is operated to crush the internal raw material shell. Then, when an appropriate time has elapsed, the operation of the vibration mill is stopped, and the crushed raw material shell is taken out and transferred into the vibration sieve machine.

Next, a sieving process is performed (step S20).
The above-described vibrating screen is preliminarily provided with a mesh having a mesh size of about 5 to 30 mesh, and the raw material shell dropped in the vibrating screen is screened by the vibrating screen to appropriately exceed the mesh. Obtain shellfish powder from which crushed shells of size are removed. In this way, by crushing the raw material shell into powder, almost all of the raw material shell can be dissolved in the dissolution step described later. Note that the crushed shell removed in this step is returned to the crushing step again.

Next, for example, the dissolution and solidification step is performed as follows (step S30).
250 kg of pure water is stored in a first tank having an appropriate capacity, and an appropriate amount of 100 kg or more and 150 kg or less is measured from the shellfish powder obtained as described above, and it is put into the first tank. In addition, calcium carbonate (for example, manufactured by Nitto Flour Chemical Co., Ltd.) as an agglomeration aid is weighed in an appropriate amount of 10 kg or more and 50 kg or less, charged into the first tank, and an agitator installed in the first tank. Stir and mix them thoroughly.

  On the other hand, an aluminum sulfate solution (preferably a sulfate sulfate, for example, manufactured by Kurosaki Chemical Co., Ltd.) of 500 kg or more and 700 kg or less is stored in the second tank. As described above, when the shellfish powder, calcium carbonate and pure water are sufficiently stirred and mixed, the aluminum sulfate solution is charged from the second tank into the first tank and stirred vigorously for an appropriate period of time of 20 minutes or longer, so that the shellfish powder and carbonate Dissolve calcium. Then, the stirrer installed in the first tank is stopped and left to stand for an appropriate time of 20 minutes or longer. This changes the solution in the first tank to a relatively hard gel.

  At this time, even if the shell powder can be dissolved in the aluminum sulfate solution, if the total amount thereof cannot be sufficiently gelled, the required cohesive force can be obtained even if it is re-dissolved in the re-dissolution step described later. Can't get.

  Here, shellfish powder contains proteins and polysaccharides in addition to calcium carbonate, which is the main component thereof, and these proteins and polysaccharides act as a crosslinking agent, and carbonate ions and aluminum sulfate produced from shellfish powder. It is considered that the gel is generated by the interaction with the aluminum ions in the solution and the interaction between the calcium ions generated from the shellfish powder and the sulfate ions in the aluminum sulfate solution.

Next, a re-dissolution process is performed as follows, for example (step S40).
A suitable mass% of dilute hydrochloric acid of 5 mass% or more and 10 mass% or less is prepared by weighing a required mass of 35% hydrochloric acid into the third tank and weighing a required mass of pure water. Alternatively, dilute hydrochloric acid prepared in advance to an appropriate mass% of 5% by mass or more and 10% by mass or less is stored in the third tank. Then, 500 kg or more and 600 kg or less of dilute hydrochloric acid is introduced from the third tank into the first tank, and the gel in the first tank is re-dissolved by stirring well for 30 minutes or more.

  As described above, it is considered that a mixed liquid-like solution of aluminum chloride and aluminum sulfate is produced by adding dilute hydrochloric acid to the gel produced in the dissolution and solidification step and dissolving it again. At this time, since dilute hydrochloric acid not containing aluminum ions exhibiting the coagulation ability is added, the concentration of aluminum ions decreases by the amount of dilute hydrochloric acid added, and the cohesive force per unit amount also decreases accordingly. However, since calcium ions produced from shellfish powder also have a coagulation ability, the decrease in cohesion due to the decrease in the concentration of aluminum ions can be offset by the addition of calcium ions.

  The solution obtained by redissolving in this way is filtered with a filter (step S50) to remove impurities and obtain a liquid flocculant. As the filter, for example, a filter in which a filter cloth having pores with a diameter of about 10 μm is disposed in an inverted hollow conical container can be used. In such a filter, the residue can be filtered out without applying external pressure, and the flocculant that spontaneously falls below the container is collected.

  In addition, you may make it improve the collection | recovery rate of a coagulant | flocculant by carrying out solid-liquid separation about the contaminant which remains in a filter using a centrifuge.

  The amount of pure water, shellfish powder and calcium carbonate in the dissolution and solidification step, and the amount of dilute hydrochloric acid in the redissolution step may be increased or decreased as long as they are in a relative ratio as described above. Needless to say. On the other hand, when the amount of pure water, shellfish powder and calcium carbonate, and the amount of dilute hydrochloric acid in the redissolution step are outside the ranges as described above, a liquid flocculant having the required cohesive force can be obtained. Can not.

  The flocculant thus produced has a wider pH range than that of the aluminum sulfate solution, and also has a strong aggregating action and a high floc strength, so the amount of addition is limited. In addition to being able to be relatively reduced, as with the aluminum sulfate solution, it has a characteristic that it has a strong cohesive force against humic substances caused by corrosion of organic substances. Thus, this aggregating agent has the advantages of both the polyaluminum chloride solution and the aluminum sulfate solution using the aluminum sulfate solution as a raw material.

  On the other hand, in the present flocculant, since pure water and dilute hydrochloric acid are added in predetermined amounts to the aluminum sulfate solution used as a raw material as described above, the concentration of contained aluminum is reduced to ½ or less compared to the raw material. Yes. In recent years, there has been a demand for further reducing the concentration of aluminum remaining in tap water, but the present flocculant can meet such demands.

  As the aluminum concentration in the flocculant decreases, the cohesive force also decreases. However, in the present flocculant, as described above, by dissolving the shell powder, it is relatively high even if the contained aluminum concentration is relatively low. Cohesive force can be exerted. Moreover, since shellfish powder is a natural product, it is highly safe even when used for producing drinking drinking water. On the other hand, since calcium carbonate is dissolved as an agglomeration aid, the required agglomeration force can be achieved.

  Next, the results of the comparative test will be described.

Example 1
The result which compared the coagulation effect with respect to artificial sewage is demonstrated.
The flocculant used in the examples of the present invention was prepared as follows. That is, the same operation as shown in FIG. 1 was performed. In step S30, 250 kg of pure water, 120 kg of shellfish powder, and 30 kg of calcium carbonate were used. In step S40, dilute hydrochloric acid prepared to 7% by mass in advance. 500 kg was used.

  The results of analyzing the thus prepared flocculant (examples of the present invention) are shown in the following table together with the prescribed values of JIS K 1450-1996, which is the standard for aluminum sulfate for tap water.

  As apparent from this table, the concentration of aluminum oxide was 4.0% by mass. Since the specified value of the concentration of aluminum oxide is 8.0 to 8.2% by mass as shown in Table 1, in the present flocculant, the concentration was approximately ½ of the specified value.

  The result of having compared the coagulation effect with respect to artificial sewage was shown in FIGS. FIG. 2 is a graph showing the result of comparing the coagulation effect with low turbidity artificial sewage, FIG. 3 is a graph showing the result of comparing the coagulation effect with medium turbidity artificial sewage, and FIG. 4 is high turbidity. It is a graph which shows the result of having compared the aggregation effect with respect to artificial sewage. In each figure, the vertical axis represents the turbidity of artificial wastewater, and the horizontal axis represents the addition capacity of the flocculant. In each figure, circles indicate the results of the examples of the present invention, and squares indicate the results of the comparative examples. In the comparative example, a sulfate sulfate (manufactured by Kurosaki Chemical Co., Ltd.) was used as a flocculant.

  In addition, artificial sewage used tap water, adjusted turbidity with the addition amount of kaolin (made by Kanto Kagaku Co., Ltd.), and adjusted alkalinity with the addition amount of sodium carbonate. That is, for low turbidity artificial sewage, adjust the turbidity to 10.8, for medium turbidity artificial sewage, adjust the turbidity to 128, and for high turbidity artificial sewage, The turbidity was adjusted to 500, and the alkalinity was adjusted to 45 mg / L to 47 mg / L in any artificial sewage. In any artificial sewage, the pH was 7.3. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As is clear from FIG. 2, in the case of artificial sewage with low turbidity, the amount added in any flocculant decreases in proportion to the amount of flocculant added, from 40 mg / L to 80 mg / L, The degree of lowering the turbidity was almost the same in both the inventive examples and the comparative examples. However, when the addition amount of the flocculant exceeded 90 mg / L, the turbidity increased according to the addition amount in the comparative example, but continued to decrease in proportion to the addition amount of the flocculant in the present invention example.

  In addition, as is apparent from FIG. 3, in the case of artificial sewage with medium turbidity, in any flocculant, when the addition amount is 20 mg / L to 50 mg / L, it decreases in proportion to the addition amount of the flocculant. However, the degree of lowering the turbidity was slightly higher in the comparative example than in the inventive example. However, when the addition amount of the flocculant exceeded 60 mg / L, the turbidity increased according to the addition amount in the comparative example, but continued to decrease in proportion to the addition amount of the flocculant in the present invention example.

  On the other hand, as can be seen from FIG. 4, in the case of artificial sewage with high turbidity, the amount of addition increases from 20 mg / L to 50 mg / L in any flocculant, which decreases in proportion to the amount of flocculant added. However, the degree of lowering the turbidity was slightly higher in the comparative example than in the inventive example. However, when the addition amount of the flocculant exceeded 60 mg / L, the turbidity increased according to the addition amount in the comparative example, but continued to decrease in proportion to the addition amount of the flocculant in the present invention example.

  From the above results, in the flocculant of the comparative example, an appropriate amount must be added to the artificial sewage according to the degree of turbidity of the artificial sewage. Therefore, since it is necessary to conduct a preliminary test or the like in order to obtain such an appropriate addition amount, a lot of labor and time are required. On the other hand, in the flocculant of the present invention example, an appropriate amount may be added regardless of the degree of turbidity of the artificial sewage, so that the labor and time described above are not required.

(Example 2)
Next, the result of comparing the coagulation effect on natural sewage will be described.
FIG. 5 is a graph showing the results of comparison of the coagulation effect with natural sewage. In the figure, the vertical axis represents the turbidity of the sewage and the horizontal axis represents the addition capacity of the coagulant. In the figure, circles indicate the results of the present invention, and squares indicate the results of the comparative example. In the examples of the present invention, the flocculant shown in Example 1 was used, and in the comparative example, a sulfuric acid bar (manufactured by Kurosaki Chemical Co., Ltd.) was used as the flocculant.

  The turbidity of natural wastewater used in this example was 1030, and the pH was 7.1. Further, a sodium hydroxide solution was appropriately added during the coagulation operation to adjust the pH to a range of 6.6 to 6.8. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As is clear from FIG. 5, in the flocculant of the present invention example, the turbidity of natural wastewater decreased as the addition amount increased up to about 800 mg / L. On the other hand, in the flocculant of the comparative example, the turbidity of natural wastewater decreased as the amount added increased to about 400 mg / L, but the amount added increased further. Even the turbidity of natural sewage did not decrease. In natural sewage, multiple substances other than kaolin used in artificial sewage are involved in the generation of turbidity, and as observed in artificial sewage, turbidity due to excessive addition of the flocculant in the comparative example was observed. Although no increase was observed, in the flocculant of the comparative example, the decrease in turbidity was limited at a stage where the addition amount was relatively small.

  Further, the degree of decrease in the turbidity of natural wastewater was higher in the flocculant of the present invention than in the flocculant of the comparative example at any addition amount. For example, the turbidity of natural sewage when 150 mg / L of the flocculant of the present invention is added is substantially the same as the turbidity of natural sewage when 300 mg / L of the flocculant of the comparative example is added. It can be said that the aggregating effect of the flocculant of the inventive example is approximately twice that of the comparative example.

(Example 3)
Next, a description will be given of the result of comparison of the influence of the temperature of the water to be treated on the cohesiveness.
FIG. 6 is a graph showing the results of a comparison of the effects of the temperature of the water to be treated on the cohesiveness, where the vertical axis indicates the turbidity of the artificial sewage and the horizontal axis indicates the temperature of the artificial sewage. In the figure, circles indicate the results of the present invention, and squares indicate the results of the comparative example. In the examples of the present invention, the flocculant shown in Example 1 was used, and in the comparative example, a sulfuric acid bar (manufactured by Kurosaki Chemical Co., Ltd.) was used as the flocculant.

  As water to be treated, artificial sewage was used in which kaolin was added to tap water to adjust the turbidity to 13, and sodium carbonate was further added to adjust the alkalinity to 47 mg / L. The pH of this artificial sewage was 7.3. The artificial sewage was kept at 5 ° C., 10 ° C., 20 ° C., 30 ° C. and 40 ° C., and the flocculant of the present invention example or the flocculant of the comparative example was added and mixed so as to be 60 mg / L. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As apparent from FIG. 6, the turbidity of the liquid to be treated in the present invention example was lower than the turbidity of the liquid to be treated in the comparative example at any water temperature. In particular, when the water temperature was 5 ° C., the turbidity of the liquid to be treated in the inventive example could be reduced to about 5/9 of the turbidity of the liquid to be treated in the comparative example. From these results, it can be seen that the cohesive force of the flocculant of the present invention example is higher than that of the comparative coagulant regardless of the temperature of the water to be treated.

(Example 4)
Next, the results of examining the influence of the pH of the water to be treated on the coagulation effect of the coagulant will be described.

  FIG. 7 is a graph showing the results of examining the influence of the pH of the water to be treated on the coagulation effect of the coagulant, where the vertical axis indicates the turbidity of the artificial sewage and the horizontal axis indicates the pH of the artificial sewage. . The flocculant shown in Example 1 was used as the flocculant.

  As water to be treated, kaolin is added to tap water to adjust turbidity to 13, and hydrochloric acid or sodium hydroxide solution is added to artificial sewage to which sodium carbonate is added to adjust alkalinity to 47 mg / L. The pH was adjusted so as to be different from about 6 to about 9. Each artificial sewage was kept at 20 ° C., and the flocculant of the present invention was added and mixed so as to be 60 mg / L. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As can be seen from FIG. 7, the turbidity of the water to be treated was sufficiently reduced in the region where the pH of the water to be treated was about 6.4 to about 8.5.

(Example 5)
Next, the results of comparison of the influence of the alkalinity of the water to be treated on the coagulation effect of the coagulant will be described.

  FIG. 8 is a graph showing the results of comparison of the influence of the alkalinity of the water to be treated on the coagulation effect of the flocculant, where the vertical axis indicates the turbidity of the artificial sewage and the horizontal axis indicates the alkalinity of the artificial sewage. ing. In the figure, circles indicate the results of the present invention, and squares indicate the results of the comparative example. In the examples of the present invention, the flocculant shown in Example 1 was used, and in the comparative example, a sulfuric acid bar (manufactured by Kurosaki Chemical Co., Ltd.) was used as the flocculant.

  As treated water, artificial sewage whose turbidity was adjusted to 9.9 by adding kaolin to tap water was used. Sodium carbonate is added to the artificial sewage to adjust the alkalinity to an appropriate value of 10 mg / L to 58 mg / L, and the flocculant of the present invention example or the flocculant of the comparative example is added and mixed to 60 mg / L. did. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As is clear from FIG. 8, in the comparative example, the turbidity decreased in a sigmoid manner as the alkalinity increased. That is, the turbidity is a value exceeding 8.0 until the alkalinity is 20, and the turbidity is decreased when the alkalinity exceeds 20, but even when the alkalinity is 30, the turbidity is about 2.5. It was. On the other hand, in the example of the present invention, when the alkalinity exceeded 10, the turbidity decreased rapidly, and when the alkalinity was 15, the turbidity decreased to about 1.5. Further, when the alkalinity was 20, the turbidity was below 1.0, and thereafter, even if the alkalinity increased, the turbidity was below 1.0.

  From these results, it can be seen that the flocculant of the example of the present invention has a high cohesive force even with a relatively low alkalinity.

(Example 6)
Next, the result of comparing the influence of the amount of the flocculant used on the pH of the water to be treated will be described.

  FIG. 9 is a graph showing the results of comparison of the effects of the use amount of the flocculant on the pH of the water to be treated. The vertical axis indicates the pH of the artificial sewage and the horizontal axis indicates the amount of the flocculant added. In the examples of the present invention, the flocculant shown in Example 1 was used, and in the comparative example, a sulfuric acid bar (manufactured by Kurosaki Chemical Co., Ltd.) was used as the flocculant.

  As water to be treated, artificial sewage was used in which kaolin was added to tap water to adjust the turbidity to 13, and sodium carbonate was further added to adjust the alkalinity to 47 mg / L. The pH of this artificial sewage was 7.3. The artificial sewage was kept at 20 ° C., and the flocculant of the present invention example or the flocculant of the comparative example was added and mixed so as to have an appropriate amount of 20 mg / L to 200 mg / L. And JWWA155: 2005 7. The agglomeration performance test was carried out according to the method specified in 1.

  As is clear from FIG. 9, in the flocculant of the comparative example, the pH of the liquid to be treated was relatively greatly reduced even with a relatively small addition amount of 20 mg / L. Further, the pH of the water to be treated decreases substantially linearly as the amount of the flocculant added in the comparative example increases. When the amount of the flocculant added in the comparative example is 100 mg / L, the pH of the water to be treated is 6.5. It was below.

  On the other hand, in the flocculant of the example of the present invention, the pH of the liquid to be treated hardly decreased at a relatively small addition amount of 20 mg / L. In addition, the pH of the water to be treated decreased substantially linearly as the amount of the flocculant added according to the present invention increased, but the degree of this decrease is moderate compared to the case of the flocculant of the comparative example described above. The pH of the water to be treated was higher than 6.5 until the addition amount of the flocculant of the present invention example was approximately 160 mg / L.

  The wastewater standard stipulates that wastewater having a pH lower than 6.5 can only be discharged after adjusting its pH to 6.5 or higher. When exceeding 100 mg / L, the process of adjusting the pH of to-be-processed water to 6.5 or more is required. However, in the case of the flocculant of the present invention example, such a step is unnecessary if the addition amount is up to 160 mg / L, and an increase in the treatment cost of the water to be treated can be suppressed.

(Example 7)
Next, the result of having treated the contaminated water containing a radioactive substance with the flocculant which concerns on this invention is demonstrated.

  The following table measured radioactive cesium in contaminated water (raw water) containing radioactive substances, and radioactive cesium in treated water (example of the present invention) obtained by treating the contaminated water with the flocculant according to the present invention. The results are shown. Here, the measurement of radioactive cesium is in accordance with gamma-ray spectrometry using a germanium semiconductor detector in the guidelines on the disposal of waste contaminated with accident-derived radioactive materials specified by the Ministry of the Environment in December 2011. Carried out.

  In addition, the contaminated water a and the contaminated water b in the table were produced by decontamination work in a gutter in Koriyama City, Fukushima Prefecture on June 17, 2013. It was caused by decontamination work on a road in Date City, Fukushima Prefecture on June 20. In addition, each value in a table | surface is shown with the total value of radioactive cesium 134 and radioactive cesium 137.

  The flocculant shown in Example 1 was used as the flocculant according to the present invention. 1 ml of the flocculant according to the present invention was added to 2000 ml of contaminated water, stirred for 1 to 2 minutes, allowed to stand for about 5 minutes to precipitate the aggregate, and filtered through a filter paper having a pore size of 10 μm to obtain a filtrate. This was treated water.

  As can be seen from Table 2, radioactive cesium could be removed to about 1/1000 or below the detection limit by treating any contaminated water with the flocculant according to the present invention.

S10 Crushing step S20 Sieving step S30 Dissolving and solidifying step S40 Remelting step S50 Filtration step

Claims (6)

When producing a flocculant containing an inorganic flocculant to be used for water treatment,
A dissolution and solidification step in which shellfish powder that has been naturally dried or dried at a temperature of 80 ° C. or less is dissolved in an aluminum sulfate solution and gelled;
The resulting re-dissolution step and a method of manufacturing a flocculant and working child and feature of the addition of 5% by weight to 10% by weight of the dilute hydrochloric acid to re-dissolve the gel.   The method for producing a flocculant according to claim 1, wherein in the dissolution and solidification step, the shell powder is suspended in water, and the resulting suspension is stirred, and an aluminum sulfate solution is added thereto to dissolve the shell powder.   The method for producing a flocculant according to claim 1, wherein a sulfate sulfate is used as the aluminum sulfate solution. In the dissolution and solidification step, the shell powder is suspended in water, and the resulting suspension is stirred, and when adding the sulfuric acid salt as an aluminum sulfate solution to dissolve the shell powder, water: shell powder: The method for producing a flocculant according to claim 1, wherein the mass ratio of sulfate sulfate equivalent to Kurosaki Chemical Co., Ltd. is adjusted to 25:10 to 15:50 to 70. The method for producing a flocculant according to any one of claims 1 to 4, wherein in the dissolution and solidification step, calcium carbonate is also dissolved in an aluminum sulfate solution at a mass ratio of 1 to 5 with respect to the shell powder 10 to 15 . A flocculant containing an inorganic flocculant for water treatment,
A flocculant produced by the production method according to claim 1.

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