JP2012217972A - Flocculation treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new flocculation method whose flocculation effect is high and which is applicable to various applications in a water treatment and a water purification by sedimentation.SOLUTION: The flocculation treatment method includes procedures where iron salts and ingredients derived from blue-green algae are added individually. Since this flocculation treatment method is of a high flocculation effect, larger flocs can be formed and can be precipitated faster, and moreover broader kinds of suspended matter such as sludge, contaminants, hazardous substances can be flocculated. Therefore, for example, it is effective for the removals of organic substances, inorganic substances and hazardous substances in a water purification plant, contaminants and hazardous substances in a wastewater plant, in addition, for recovery and removal of contaminants and sludge contained in the water, etc., suppression of generation of muddy water and turbid water in civil engineering works in a water area and removal of contaminants and sludge, recovery and removal of hazardous substances collected from water bottoms, etc. when civil engineering works are performed in a water area, and removal of algal bloom and microalgae (phytoplankton), etc.

Description

  The present invention relates to water treatment / water purification technology by agglomeration treatment of waste water, muddy water, muddy water, and other various types of suspended water. More specifically, the present invention relates to a coagulation treatment method including a procedure of individually adding an iron salt and a cyanobacteria-derived component.

  In order to supply water suitable for drinking at a water purification plant or the like, it is necessary to purify the water by removing organic substances, inorganic substances and harmful substances from the viewpoint of safety. Industrial wastewater, domestic wastewater, livestock wastewater, etc. must be discharged after removing pollutants and harmful substances as much as possible from the viewpoint of reducing environmental impact.

  When performing civil engineering work in water areas such as rivers, canals, harbors, inner bays, and lakes, it is necessary to take measures to suppress the generation of muddy water and muddy water. In closed and semi-enclosed waters such as harbors, lakes, tidal flats, canals, and moats, there are cases where large amounts of sea lions and microalgae (phytoplankton) are generated, and it is necessary to effectively remove them.

  A sedimentation separation method is known as a method for treating waste water, muddy water, muddy water, and other various types of suspended water. A flocculant is added to the suspension of mud, pollutants, etc. to agglomerate and settle, and these substances are separated from the water and removed.

  As the flocculant, inorganic flocculants such as polyaluminum chloride are widely used. However, it is difficult to form a sufficiently large floc even when these flocculants are used. Moreover, since polyaluminum chloride has poor biodegradability, there is a concern about the influence on the natural environment when used in large quantities in water.

  On the other hand, for example, Patent Document 1 discloses a water treatment flocculant in which guar gum, which is a neutral plant-produced water-soluble polysaccharide, is dissolved in an acidic ferric aqueous solution. The floc generation method of adding polysaccharide (xanthan gum or sodium alginate) after adjusting the pH by adding water is added to and mixed with seaweed paste in muddy water, and then an aqueous solution of calcium compound is added.・ Muddy water treatment methods to be mixed are described respectively.

  Suizenjinori (scientific name "Aphanothece sacrum") is a photosynthetic microorganism of freshwater cyanobacterium that grows naturally in the Kyushu region of Japan. Single-cell individuals form colonies in agar substrates.

  It is known that the extracellular matrix of Suizenjinori contains a polysaccharide having a molecular weight of about 16 million, which is unique to this species. This polysaccharide contains 11 or more kinds of constituent monosaccharides such as glucuronic acid, galacturonic acid, galactosamine, as well as sulfated muramic acid uniquely found in this sugar. Moreover, it has many constituent monosaccharides containing a sulfate group.

Patent Document 4 discloses a sugar derivative derived from Suizendinori, and Patent Document 5 discloses a metal recovery method using a polymer extracted from Suizendinori.
JP 2001-219005 A Japanese Patent Laid-Open No. 10-216737 JP 2007-136296 A International Publication WO2008-62574 Pamphlet JP 2011-1596 A

  An object of the present invention is to provide a novel coagulation treatment means that has a high coagulation effect and can be applied to various uses in water treatment and water purification by sedimentation separation.

  In the present invention, an aggregation treatment method including a procedure of individually adding an iron salt and a cyanobacteria-derived component is provided.

  Since this agglomeration treatment method has a high agglomeration effect, a large floc can be formed and sedimentation can be performed more quickly. In addition, a wide variety of suspensions such as mud, pollutants and harmful substances can be aggregated.

  Therefore, for example, removal of organic substances / inorganic substances / hazardous substances at water treatment plants, removal of pollutants / hazardous substances at wastewater treatment plants, recovery / removal of harmful substances contained in water, etc., and civil engineering work in water areas Suppression of muddy water and turbid water generation and removal of pollutants and mud, recovery and removal of harmful substances rolled up from the bottom of the water during civil engineering work in water, organicity such as blue seaweed and microalgae (phytoplankton) in water It is effective for removing suspended matters.

  Moreover, since this method can be applied if the pH of the suspension water is at least in the range of 4 to 11, the procedure for pretreatment of the suspension water such as pH adjustment can be omitted or simplified. Therefore, the suspension can be aggregated and settled more easily and effectively.

  Both the iron salt and cyanobacteria-derived component used in this method are components derived from the natural world, and even if they are added in a relatively large amount to a water area, the environmental load is small. In addition, since this coagulation treatment method has a high coagulation effect, there is almost no residual coagulant in the supernatant after coagulation / sedimentation. Therefore, even if these flocculants are added to water or the like, there is an advantage that the influence on the environment is small.

  According to the present invention, the coagulation effect can be improved in water treatment and water purification by sedimentation separation. In addition, the present invention can be applied to a wide range of suspended water aggregation processes such as water for use in beverages, drainage, muddy water, turbid water, and the like.

  The present invention includes all aggregating treatment methods including at least a procedure of individually adding an iron salt and a cyanobacteria-derived component.

  For example, after collecting suspended water, either iron salt or a cyanobacteria-derived component is added and stirred and mixed. Next, after adding the other, stirring and mixing, the suspended water is allowed to stand and the suspension is allowed to settle. Then, when the transparency of the supernatant liquid reaches the reference value, the suspension is settled and separated, and when it does not reach the reference value, the same water treatment is repeated. Thereby, various suspensions can be effectively aggregated, settled, separated and removed.

  The iron salt and the cyanobacterium-derived component may be added individually to the suspension water, and the order of addition is not particularly limited.

  For example, when a cyanobacteria-derived component is added after the iron salt is added, the iron salt added to the suspension water first aggregates the particles of the suspension to form a floc having a certain size. Iron salts are positive ions, whereas cyanobacteria-derived components contain polysaccharides as active ingredients and have negative ions. Therefore, by adding a cyanobacteria-derived component, the iron salt and the aggregated particles thereof and the polysaccharide are combined to form a larger floc and enhance sedimentation.

  In addition, for example, when an iron salt is added after adding a cyanobacteria-derived component, first, the polysaccharide in the cyanobacteria-derived component forms a crosslinked structure of the polymer and traps the suspension therein to some extent. Next, by adding the iron salt, the iron salt itself aggregates the suspension, and the iron salt and the polysaccharide are combined to form a larger floc and enhance the sedimentation property.

  Therefore, even when either the iron salt or the cyanobacteria-derived component is added first, almost the same aggregation effect can be obtained.

  Although the iron salt used by this method is not specifically limited, For example, ferric salts, such as ferric chloride, ferric sulfate, and polyferric sulfate, can be used conveniently. These substances may be added to the suspension water in the form of, for example, a solid agent containing at least a ferric salt or an aqueous solution.

  For example, in the case of ferric chloride, the amount of ferric salt added is preferably 0.5 to 1,000 mg, more preferably 1 to 500 mg, and most preferably 5 to 100 mg per liter of suspended water. It is.

  The cyanobacterium-derived component used in this method is not particularly limited as long as it contains a polysaccharide as an active ingredient. As a cyanobacteria-derived component containing a polysaccharide as an active ingredient, for example, a paste prepared from algae bodies of cyanobacteria may be used, or a component such as a polysaccharide extracted from cyanobacteria may be directly or prepared. May be used.

  Cyanobacteria (scientific name "Chroococcaceae") microorganisms, for example, Chroococcus limneticus (scientific name), Chroococcus disperses (scientific name), Merismopedia elegans (scientific name), suizenjinori (scientific name " Aphanothece sacrum "), Aphanothece clathrata (scientific name), and the like are more preferable, and a swallowtail (scientific name" Aphanothece sacrum ") or its related species is most preferable. For example, these cyanobacteria may be hydroponically cultivated or field-cultivated and used as a raw material for cyanobacteria-derived components.

  As a method of preparing the algal body of cyanobacteria in a paste form, a known method can be adopted and is not particularly limited. For example, algal bodies of cyanobacteria are placed in a low-concentration sodium hydroxide aqueous solution, mixed and pulverized with a mixer or the like until a paste is formed, the paste-like material-containing solution is boiled for several hours, and then allowed to cool. A cyanobacteria-derived paste can be prepared by the above procedure.

  As a method for extracting a component such as a polysaccharide from cyanobacteria, a known method can be adopted, and the method is not particularly limited. For example, cyanobacterium is directly or after preparing a dry pulverized product, it is immersed in a solvent for a certain period of time to remove water-soluble and fat-soluble pigments. As the solvent, for example, an organic solvent such as ethanol can be used. Next, it transfers to aqueous solution, such as sodium hydroxide and sodium carbonate, and hydrolyzes by heat-processing for a fixed time. By the above procedures, active ingredients such as polysaccharides can be extracted from cyanobacteria.

  Moreover, the component extracted from the cyanobacterium may be neutralized, and the solution may be used as an aqueous solution of the cyanobacterium-derived component. In addition, for example, what was dried at low temperature after dehydration and pulverized, what the powder was solidified, and what the powder was dissolved in a solution may be used as the cyanobacteria-derived component.

  The amount of the cyanobacterium-derived component added is, for example, preferably 0.5 to 2,000 mg, more preferably 1 to 1,000 mg, and most preferably 5 to 500 mg per liter of suspended water.

  The cyanobacteria-derived component is preferably a polysaccharide having a weight average molecular weight of 2 million to 40 million, more preferably a polysaccharide having a weight average molecular weight of 8 million to 30 million, Preferably, a polysaccharide having a weight average molecular weight of 10 million to 20 million is contained as an active ingredient. The weight average molecular weight can be measured by a known method, for example, by gel filtration chromatography.

  The polysaccharide contained as an active ingredient of the present invention preferably contains 5 to 30 types, more preferably 8 to 30 types, and even more preferably 11 to 30 types of constituent monosaccharides. This polysaccharide includes various sugar chain molecules having slightly different structures in the molecular structure, and also contains many sulfate groups, carboxylic acid groups, amino groups, and the like, and is an ampholyte. Therefore, it has a range in the expression of ion exchange capacity, and has stability of material characteristics against changes in pH and the like. Therefore, the flocculation method according to the present invention has the advantage that the procedure for pretreatment such as pH adjustment can be omitted or simplified, and the suspension can be flocculated and settled more easily and effectively.

  Examples of the constituent monosaccharides of this polysaccharide include neutral sugars such as glucose, galactose, mannose, rhamnose, fucose, xylose, and arabinose, and acidic sugars such as uronic acids (glucuronic acid and galacturonic acid), sulfated muramic acid, and the like. And galactosamine which is an amino sugar.

  Of these, uronic acids have a carboxyl group and have the property of capturing a positive ion to form a complex. In the present invention, it is presumed that the positive ion iron salt aggregates the particles of the suspension, and uronic acid in the polysaccharide gathers around the iron ion and becomes entangled to cause a high degree of aggregation.

  Therefore, this polysaccharide preferably contains at least uronic acids as constituent monosaccharides. Although the ratio of uronic acids in all the constituent monosaccharides in the polysaccharide is not particularly limited, for example, 2 to 20% is preferable, 4 to 15% is more preferable, and 5 to 12% is most preferable.

  In addition, the qualitative / quantitative analysis of the constituent monosaccharide can be performed by a known method, for example, by high performance liquid chromatography, analysis by a mass spectrometer, or the like.

  This polysaccharide has preferably 1 to 20%, more preferably 3 to 15%, and even more preferably 5 to 10% of a constituent monosaccharide containing a sulfate group. Similar to the carboxyl group, the sulfate group has a property of capturing a positive ion to form a complex. Therefore, it is assumed that the sulfate group in the polysaccharide plays an important function for the aggregation of the iron salt and the polysaccharide in the present invention, like uronic acid.

  In addition, the quantitative analysis of a sulfate group can be performed by a well-known method, for example by analysis by a mass spectrometer. The sulfur content in the polysaccharide can be determined by a known method such as ICP emission spectroscopy.

  As described above, the present invention can be applied to a wide range of suspended water coagulation treatments. For example, removal of organic and inorganic substances in water treatment plants, removal of pollutants in wastewater treatment plants, suppression of mud and muddy water generation in civil engineering works and removal of pollutants and mud, aquatic and microalgae in water areas ( It is effective for removing organic suspensions such as phytoplankton).

  In addition, the polysaccharide according to the present invention has the property of binding to positive ions such as metal salts as described above. Therefore, the present invention, for example, removes harmful substances from water purification plants, wastewater treatment plants, etc., collects and removes harmful substances contained in water, and harmful substances wound up from the bottom of the water during civil engineering work in water areas. It has the advantage of being effective for recovery and removal of substances.

  Hazardous substances that can be removed include, for example, heavy metals such as lead, copper, chromium, cadmium, mercury, zinc, arsenic, manganese, cobalt, nickel, molybdenum, tungsten, tin, bismuth, uranium, plutonium, cesium, strontium, zinc, Examples include radioactive isotopes such as manganese.

  In addition, the present invention is effective for any suspension water of fresh water, brackish water, and seawater.

  In Example 1, a cyanobacteria-derived component was prepared.

  A field-cultivated suizendinori was soaked in ethanol for a certain period of time to remove water-soluble pigments and fat-soluble pigments. Next, it moved to the sodium hydroxide aqueous solution, heat-processed, and extracted the component which mainly has a polysaccharide from cyanobacteria. Hydrochloric acid was added dropwise to the extract to neutralize it to around pH 7.

  Next, ethanol was added to the neutralized solution for dehydration treatment, followed by low-temperature drying treatment to obtain a powder mainly composed of a polysaccharide having a weight average molecular weight of 2 million to 20 million. This powder was dissolved in distilled water to prepare an aqueous solution of a cyanobacterium-derived component and used in the following examples.

  In Example 2, the aggregation effect of the cyanobacterium-derived component was examined.

As a suspension model, No. 1 shown in Table 1. 1-No. Six test cases were prepared. Each test water was put into a 200 mL beaker and prepared to have a turbidity of 50 to 200 NTU. As kaolin, Hakuto soil made by Wako Pure Chemical Industries, Ltd. was used. In addition, marine microalgae with scientific name “Tetraselmis tetrathele” and freshwater aoko with scientific name “Microcrystis aetuginosa” were used.

  The experimental temperature was set to 21 ° C., and an aqueous ferric chloride solution or an aqueous solution of a cyanobacterium-derived component was added to each test case to a final concentration of 50 mg / L, and the mixture was stirred for 5 minutes and then allowed to stand.

  Similarly, the experiment temperature is set to 21 ° C., and an aqueous ferric chloride solution is added to each test case so that the final concentration is 50 mg / L. After stirring for 5 minutes, an aqueous solution of cyanobacteria-derived components is added. The final concentration was 50 mg / L, and the mixture was stirred for 5 minutes and allowed to stand.

Turbidity (NTU) was measured before the addition of these additive materials and 5, 10, 30 minutes after standing. The turbidity was measured with a portable turbidimeter (product name “TB-25A”, manufactured by DKK / TOA). The turbidity removal rate was calculated by calculating the measured value using the equation shown in “Equation 1” and evaluated.

  The results are shown in FIG. FIG. 1 is a graph showing the turbidity removal rate when an iron salt and / or cyanobacteria-derived component is added. In the graph, the horizontal axis represents each test case, and the vertical axis represents the turbidity removal rate (%). The three values in each test case are, from the left, the results when iron salt is added alone (white graph), the results when cyanobacterium-derived components are added (hatched graph), iron salt and orchid, respectively. The result (black graph) at the time of adding an algae origin component is represented.

  As shown in FIG. 1, in the case of kaolin and mud, in both cases of seawater and tap water, when cyanobacterium-derived components are added, the turbidity removal rate is significantly higher than when iron salts are added. it was high. Moreover, when both the additive materials of the iron salt and the aqueous solution of the cyanobacterium-derived component were added, the turbidity was almost 100% removed.

  In the test case contaminated with algae, in both cases of marine microalgae and freshwater aoko, when both iron salt and cyanobacterium-derived components are added, iron salt or cyanobacterium-derived components are added alone Compared with, the turbidity removal rate was remarkably high.

  The above results show that by treating the suspension with both iron salt and cyanobacteria-derived components, mud and the like can be aggregated almost 100%, and the organic suspension can be effectively aggregated. Indicates.

  In Example 3, the size of the aggregated particles formed in Example 2 was measured.

  Test case No. 2 of Example 2 3 (mud / seawater) and no. To 5 (marine microalgae), an aqueous ferric chloride solution is added to a final concentration of 50 mg / L, and after stirring for 5 minutes, an aqueous solution of cyanobacteria-derived components is added to a final concentration of 50 mg / L. Stir for 5 minutes and let stand. As a comparative example, an aqueous ferric chloride solution was added to the same test case so as to have a final concentration of 50 mg / L, stirred for 5 minutes, and then allowed to stand. Five minutes after standing, the maximum diameter of the formed aggregated particles was measured with a microscope (product name “VH8000”, manufactured by Keyence), and an average value and a standard deviation value were obtained.

  The results are shown in FIG. FIG. 2 is a graph showing the maximum diameter of agglomerated particles formed when both the iron salt and cyanobacteria-derived components are added. In the graph, the horizontal axis represents each test case, and the vertical axis represents the maximum diameter (mm) of the aggregated particles. The two values in each test case are, from the left, the result when both the iron salt and cyanobacteria-derived ingredients are added (black) and the result when the iron salt is added alone (comparative example). , White).

  As shown in FIG. 2, the maximum diameter of the agglomerated particles formed when both the ferric chloride aqueous solution and the aqueous solution of cyanobacteria-derived components are added to the mud and marine microalgae test cases is as follows. Compared to the case where the aqueous iron solution was added alone, the size was about 5 times.

  In Example 4, the coagulation effect was examined when iron salts and various sugars were added as additive materials to the suspension model.

  As additive materials, ferric chloride aqueous solution, (1) aqueous solution of cyanobacteria-derived component, (2) glucose aqueous solution, (3) starch aqueous solution, (4) dextrin aqueous solution, and (5) sucrose aqueous solution were prepared. The experimental temperature was set to 21 ° C., and the test case no. 2 (kaolin / tap water) was added ferric chloride aqueous solution to a final concentration of 50 mg / L and stirred for 5 minutes, and then any of the additive materials (1) to (5) was added to a final concentration of 50 mg / L. L was added, stirred for 5 minutes, and allowed to stand. Five minutes after standing, the maximum diameter of the formed aggregated particles was measured with a microscope (product name “VH8000”, manufactured by Keyence), and an average value and a standard deviation value were obtained.

  Further, the formed aggregated particles were immersed in a 50 cm deep conical container containing tap water, and the sedimentation rate of the aggregated particles was measured.

  The results are shown in FIGS. FIG. 3 is a graph showing the maximum diameter of the aggregated particles formed when the iron salt and each saccharide are added, and FIG. 4 is a graph showing the sedimentation rate of the aggregated particles formed when the iron salt and each saccharide are added. is there.

  In the graph of FIG. 3, the horizontal axis represents each additive material, and the vertical axis represents the maximum diameter (mm) of the aggregated particles. In the graph of FIG. 4, the horizontal axis represents each additive material, and the vertical axis represents the sedimentation rate (mm / min) of the aggregated particles.

  As shown in FIG. 3, the maximum diameter of the aggregated particles formed when both the iron salt and cyanobacteria-derived ingredients are added is 3 times or more compared to the case where the iron salt and other saccharides are added. It was the size of.

  As shown in FIG. 4, the settling rate of the aggregated particles formed when the iron salt and cyanobacteria-derived component are added is 1071.4 mm / min, which is the highest compared to the case where the iron salt and other saccharides are added. It was fast.

  In Example 5, the water purification effect in the case of adding both the iron salt and cyanobacteria-derived component additive materials was compared with the water purification effect in the case of adding both the calcium salt and seaweed-derived component additive materials.

  Test case No. 2 of Example 2 2 (mud / tap water) and No. 2 5 (marine microalgae) was prepared. Test case no. 2 has a turbidity of 100 NTU and test case no. The turbidity of 5 was 50 NTU.

  As additive materials, (1) a ferric chloride aqueous solution and an aqueous solution of a cyanobacterium-derived component, and (2) a calcium chloride aqueous solution and an aqueous solution of a seaweed-derived component were prepared. An aqueous solution of the seaweed-derived component was obtained by immersing 50 g of dried kombu in 450 mL of water for 30 minutes to form a paste, adding 300 mL of 1% sodium carbonate aqueous solution to 200 g of the paste, heating and boiling for 5 minutes. .

  In the case where the additive material of (1) was added, the experimental temperature was set to 21 ° C., an aqueous ferric chloride solution was added so that the final concentration was 50 mg / L, and the mixture was stirred for 5 minutes. Was added to a final concentration of 50 mg / L, stirred for 5 minutes, and allowed to stand.

  In the case where the additive material of (2) is added, similarly, the experimental temperature is set to 21 ° C., an aqueous calcium chloride solution is added so that the final concentration is 10 g / L, and the mixture is stirred for 5 minutes. An aqueous solution of the components was added to a final concentration of 480 mg / L, stirred for 5 minutes, and allowed to stand.

  Turbidity (NTU) was measured before the addition of the additive material and after 5, 10, 30 minutes from standing. The turbidity was measured with a portable turbidimeter (product name “TB-25A”, manufactured by DKK / TOA) as in Example 2. The turbidity removal rate was calculated by calculating the measured value using the equation shown in the above “Equation 1” and evaluated.

  In addition, test case no. 2 (mud / tap water) was subjected to COD analysis of the supernatant water after removing turbidity using the COD pack test (Kyoritsu Riken).

  The results are shown in FIGS. FIG. 5 is a graph showing the turbidity removal rate when an iron salt and cyanobacteria-derived component or a calcium salt and seaweed-derived component are added. FIG. 6 is an iron salt and cyanobacteria-derived component, or calcium salt and seaweed. It is a graph showing the result of COD analysis of the supernatant water after removing turbidity in the case of adding a derived component.

  In the graph of FIG. 5, the horizontal axis represents each test case, and the vertical axis represents the turbidity removal rate (%). From the left, the three values in each test case are the results when the additive material is not added (control, white graph), the results when the calcium salt and seaweed-derived components are added (shaded graph), respectively. The result (black graph) at the time of adding an iron salt and a cyanobacteria-derived component is represented.

  In the graph of FIG. 6, the horizontal axis represents the additive material, and the vertical axis represents the COD value (mg / L). From the left, the three values in the graph are the results when the additive material is not added (control, white graph), the results when the calcium salt and seaweed-derived components are added (shaded graph), The result (black graph) at the time of adding an iron salt and a cyanobacterium-derived component is represented.

  As shown in FIG. 5, when an iron salt and a cyanobacteria-derived component are added to an inorganic suspension (kaolin / tap water), almost 100% of turbidity can be removed as in the case of adding a calcium salt and a seaweed-derived component. It was.

  In addition, in the organic suspension (sea microalgae) test case, when adding calcium salt and seaweed-derived components, turbidity could hardly be removed, whereas iron salt and cyanobacteria-derived components were added. In the case, turbidity could be removed almost 100%.

  As shown in FIG. 6, as a result of COD analysis of the supernatant water after removing the turbidity when the additive material is added to the test case, the COD value when calcium salt and seaweed-derived components are added is as high as about 50 mg / mL. On the other hand, when the iron salt and cyanobacteria-derived component were added, the COD value could be kept low even after the addition. This result shows that when water purification is performed using iron salts and cyanobacteria-derived components as flocculants, both flocculants remain in the supernatant after flocculation / sedimentation, and these flocculants are added to water areas. This suggests that the impact on the environment is small.

  In Example 6, the influence of pH in water purification using iron salts and cyanobacteria-derived components was examined.

  Test case No. 2 of Example 2 2 (mud / tap water) was prepared, the turbidity was adjusted to 200 NTU, and hydrochloric acid or sodium hydroxide was added to adjust the pH to 2, 3, 4, 6, 11 respectively.

  The experimental temperature was set to 21 ° C., and an aqueous ferric chloride solution was added to each test case to a final concentration of 50 mg / L. After stirring for 5 minutes, the aqueous solution of cyanobacteria-derived components was adjusted to a final concentration of 50 mg / L. And stirred for 5 minutes and allowed to stand.

  Turbidity (NTU) was measured before the addition of the additive material and after 5, 10, 30 minutes from standing. The turbidity was measured with a portable turbidimeter (product name “TB-25A”, manufactured by DKK / TOA) in the same manner as in Example 2. The turbidity removal rate was calculated by calculating the measured value using the equation shown in the above “Equation 1” and evaluated.

  The results are shown in FIG. FIG. 7 is a graph showing the relationship between the pH of the suspension and the turbidity removal rate. In the graph of FIG. 7, the horizontal axis represents the pH of the test case, and the vertical axis represents the turbidity removal rate (%).

  As shown in FIG. 7, when the pH of the suspension was in the range of 4 to 11, turbidity of 98% or more could be removed. Further, even at pH 2 and pH 3, turbidity of 80% or more could be removed.

  This result shows that the polysaccharide that is the main component of the cyanobacteria-derived component contains 5 or more types of constituent monosaccharides, has a wide range of ion exchange ability, and has stability against changes in pH. I guess it is because.

  Therefore, the results of this experiment show that by adopting a method of adding iron salt and cyanobacteria-derived liquid components to the suspension water, the procedure for pretreatment such as pH adjustment can be omitted or simplified, and the suspension can be performed more simply and effectively. This suggests that the product can be aggregated and settled.

  In Example 7, the addition concentration when an iron salt and a cyanobacterium-derived component were used was examined.

  Test case No. 2 of Example 2 2 (mud / tap water), the turbidity is adjusted to 200 NTU, the experimental temperature is set to 21 ° C., and ferric chloride aqueous solution is added to each test case at a final concentration of 5, 12.5, 25, Add to 50 mg / L and stir for 5 minutes, then add the aqueous solution of cyanobacteria-derived components to final concentrations of 5, 12.5, 25, and 50 mg / L, respectively, and stir for 5 minutes. Left to stand.

  Turbidity (NTU) was measured before addition of the additive material and 30 minutes after standing. The turbidity was measured with a portable turbidimeter (product name “TB-25A”, manufactured by DKK / TOA) in the same manner as in Example 2. The turbidity removal rate was calculated by calculating the measured value using the equation shown in the above “Equation 1” and evaluated.

  The results are shown in FIG. FIG. 8 is a graph showing the relationship between the flocculant addition concentration and the turbidity removal rate. In the graph of FIG. 8, the horizontal axis represents the total addition concentration (mg / mL) of both additive materials, and the vertical axis represents the turbidity removal rate (%).

  As shown in FIG. 8, 90% or more of turbidity could be removed after 30 minutes of mixing and standing by adding a total of 5 mg / mL or more of iron salt and cyanobacteria-derived components. This result suggests that the flocculant according to the present invention has a high flocculant effect, and that the flocculant effect can be obtained even when a small amount of flocculant is added.

  The present invention, for example, removes organic substances / inorganic substances / hazardous substances from a water treatment plant, removes pollutants / hazardous substances from a wastewater treatment plant, collects / removes harmful substances contained in water, etc., and civil engineering in the water area. Suppression of mud and muddy water in construction and removal of pollutants and mud, removal of harmful substances rolled up from the bottom of the water during civil engineering work in waters, organicity such as sea lions and microalgae (phytoplankton) in waters It can be applied to the removal of suspension. It is also effective for any suspension of fresh water, brackish water, and seawater.

  In addition, the iron salt and cyanobacteria-derived component used in the aggregating treatment method according to the present invention are components derived from nature, and even when added in a relatively large amount to a water area, the environmental load is small. In addition, since this coagulation treatment method has a high coagulation effect, there is almost no residual coagulant in the supernatant after coagulation / sedimentation. Therefore, for example, even if these flocculants flow out during construction due to typhoons or heavy rain, the influence on the water environment can be minimized.

In Example 2, the graph showing the turbidity removal rate at the time of adding an iron salt and / or a cyanobacterium origin component. In Example 3, the graph showing the maximum diameter of the aggregated particle formed when both the addition material of the iron salt and the cyanobacterium-derived component are added. In Example 4, the graph showing the maximum diameter of the aggregated particle formed when adding an iron salt and each saccharide | sugar. In Example 4, the graph showing the sedimentation rate of the aggregated particle formed when adding an iron salt and each saccharide | sugar. In Example 5, the graph showing the turbidity removal rate at the time of adding the extraction component derived from an iron salt and cyanobacteria, or a calcium salt and seaweed. In Example 5, the graph showing the result of COD analysis of the supernatant water after removing turbidity in the case of adding an iron salt and a cyanobacteria-derived component or a calcium salt and a seaweed-derived extract component. In Example 6, the graph which shows the relationship between pH of a suspension, and a turbidity removal rate. In Example 7, the graph which shows the relationship between the addition density | concentration of a flocculant and a turbidity removal rate.

Claims (5)

  A coagulation treatment method including a procedure of individually adding an iron salt and a cyanobacteria-derived component.   The aggregation treatment method according to claim 1, wherein the cyanobacterium-derived component contains a polysaccharide having a weight average molecular weight of 2 million to 20 million as an active ingredient.   The aggregation treatment method according to claim 2, wherein the polysaccharide contains 5 to 20 kinds of constituent monosaccharides.   The aggregation treatment method according to claim 2, wherein the polysaccharide contains uronic acids as constituent monosaccharides.   The aggregation treatment method according to claim 2, wherein the polysaccharide has 1 to 20% of a constituent monosaccharide containing a sulfate group.

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