JP2007136405A - Foaming solid flocculant for water treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foaming solid flocculant which does not generate dust and rapidly foams and collapses to be dispersed when mixed in waste water. <P>SOLUTION: The foaming solid flocculant for water treatment comprises 50-90 wt.pts. of an inorganic flocculant such as aluminum sulfate and gypsum or of an organic floculant such as a polyacryl amide and a salt of a polyacrylic acid, 50-10 wt.pts. of a foaming agent such as sodium carbonate and sodium hydrogen carbonate, and 0.1-20 wt.pts. of calcium silicate as a forming auxiliary agent (a total amount of the flocculant and the foaming agent is 100 wt.pts.). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a foamable solid flocculant for water treatment. More specifically, the present invention relates to a solid flocculant used for applications such as industrial wastewater treatment, industrial wastewater treatment, sludge and blue water treatment of ponds, rivers, water and sewage water treatment and blue water treatment, manure treatment, and the like.

  In the case of wastewater treatment using a flocculant, the commonly used flocculants include inorganic flocculants represented by aluminum sulfate, polyaluminum chloride, iron chloride and the like, and water-soluble high repellency represented by polyacrylamide and the like. There are organic flocculants composed of molecules.

  Inorganic flocculants mainly have the effect of neutralizing the charge of suspended particles, so the transparency of the supernatant after use is good and the water content can be easily separated from the precipitate. Since it is small, the aggregation rate is slow or it is often an acidic substance, and it has been necessary to carry out a neutralization treatment with an alkali after the treatment. On the other hand, organic flocculants are generally expensive, and flocs formed are larger than when inorganic flocculants are used. There were problems such as turbidity remaining in the water and difficulty in separating water from the sediment floc. Therefore, a treatment method using both an inorganic flocculant and an organic flocculant is common. In this case, the inorganic flocculant is added first and then rapidly stirred to form a micro floc group. Then, the organic flocculant is added in the next step, and the flocculent group is stirred slowly to obtain a larger flocculant group. A processing method for forming is applied. In this way, the method of adding the two types of flocculants separately with a time difference is troublesome and requires a plurality of flocculant charging means, and not only the equipment area increases, but also the apparatus itself increases. There was a disadvantage.

On the other hand, recently, it has been proposed to use a powdery flocculant in which an inorganic flocculant and an organic polymer flocculant are mixed (Japanese Patent Laid-Open No. 2004-154726). Alternatively, an inorganic flocculant mainly composed of a relatively neutral material such as gypsum, artificial zeolite, or cement has been proposed. (Japanese Patent Laid-Open No. 9-276604)
JP 2004-154726 A JP 09-276604 A

When the flocculant is put into the water treatment tank in the form of powder, the equipment for learning the powder at regular intervals of time and quantity is not only expensive, but also causes phenomena such as shelves in the equipment. There was a problem that troubles such as supply stop occurred from time to time. In addition, when used on site as a coagulation treatment agent such as sea urchins and sludge generated in ponds and lakes, muddy water at construction sites, etc., if it is in powder form, it may not only be scattered by the wind at the time of supply, but also wide There was a problem that it was difficult to go to the area of the range and it took time. Further, since it cannot be used in an environment that dislikes dust, such as a semiconductor factory, a means for dust prevention has been desired.
On the other hand, in order to granulate powder, a method using cellulose or a water-soluble polymer material as a binder is known. However, in this method, the amount of binder added increases, and the solid material Insufficient strength or organic matter remains in the water after the coagulation treatment, raising the value of COD and BOD, which may cause contamination.

  As a result of diligent research to solve these problems, the present inventors have combined a water treatment flocculant component, a foaming agent, and calcium silicate as a molding aid into a solid water treatment flocculant. It came to solve the said subject.

  That is, the present invention includes 50 to 90 parts by weight of a water treatment flocculant, 50 to 10 parts by weight of a foaming agent, and 0.1 to 20 parts by weight of calcium silicate (the total amount of the water treatment flocculant and the foaming agent is 100 parts by weight. A foamable solid aggregating agent for water treatment.

  The following effects are brought about by implementation of the present invention. First, when the foamable solid flocculant for water treatment of the present invention is added to wastewater, the flocculant component can be quickly and uniformly diffused in the wastewater. This can exhibit an agglomeration effect comparable to when the flocculant of the present invention is added in a powder state. In addition, since the molding aid and the like settle together with the flocculant, BOD and COD are not adversely affected. Furthermore, when a flocculant is added to sewage outdoors, it can be added without generating dust even when agglomerates generated in ponds or lakes are agglomerated. In addition, it can be used for wastewater treatment in semiconductor factories that dislike dust.

  The foamable solid flocculant for water treatment of the present invention will be specifically described below.

  As the water treatment flocculant to be blended with the foamable solid flocculant for water treatment of the present invention, powdery inorganic or organic flocculants usually used for water treatment are not particularly limited and can be used.

  Specifically, the inorganic flocculants include aluminum salts such as aluminum sulfate, aluminum hydroxide, ammonium alum, potassium alum, sodium aluminate, polyaluminum chloride, ferrous chloride, ferric chloride, polyiron sulfate. , Iron salt such as silica iron, gypsum such as dihydrate gypsum and hemihydrate gypsum, sodium type, calcium type and iron type of artificial or synthetic zeolite, natural zeolite, ash components such as volcanic ash and coal ash, cement etc. It is also possible to use one or more of these.

  Organic flocculants include water-soluble polymer materials such as polyacrylamide, polyacrylate, acrylamide and acrylate copolymer, alginic acid, alginate, polyvinyl alcohol, CMC, MC (methylcellulose), and alginic acid. Salt, xanthan gum, guar gum, HEC (hydroxyethyl cellulose), polyethylene oxide, chitosan, agar, gelatin, polymaleic acid, polystyrene sulfonate, polyvinyl sulfonic acid, polyimide, polyamine, polyacrylic acid ester, and the modified products thereof 1 type, or 2 or more types of these can also be used. Moreover, these copolymers can also be used, and a copolymer of sodium acrylate and acrylamide is particularly preferable.

  Inorganic flocculants and organic flocculants can be used alone or in combination, but flocculants mainly composed of inorganic flocculants are preferred. Specifically, it is preferable to combine in the range of 0.1 to 20 parts by weight of the organic flocculant with respect to 100 parts by weight of the inorganic flocculant. If the content of the organic flocculant is too large, excess organic flocculant is not taken into the floc and remains in the treated water, which may cause secondary aggregation. If the amount is too small, the floc strength becomes weak and difficult to dewater, and if it is extremely small, the floc becomes fine and may not be dewatered.

The blending amount of the water treatment powder flocculant in the preparation is not particularly limited,
It is preferable that it is 50-90 weight part with respect to a total of 100 weight part of a coagulant | flocculant and a foaming agent. If it is less than the lower limit, the agglomeration performance is insufficient, which is not preferable. If the upper limit is exceeded, the foaming performance is insufficient.

  Examples of the foaming agent used in the present invention include alkali or alkaline earth carbonates such as sodium carbonate, sodium hydrogen carbonate, ammonium carbonate, potassium carbonate, calcium carbonate, sodium sesquicarbonate, and the like. May be. Among these, alkali carbonates are preferably used because they are easily dissolved in water. A foaming agent is added and used in the range of 50-10 weight part of foaming agents with respect to 50-90 weight part of coagulants for water treatment. If the addition amount of the foaming agent is small, the foaming effect is reduced, and if it is too much, the aggregation effect cannot be obtained sufficiently, which is not preferable.

  In the foamable solid flocculant for water treatment of the present invention, when sufficient self-disintegration by the foaming agent is not obtained in the aggregation treatment step, it is preferable to blend the foaming agent with a foaming aid. As the foaming aid, a water-soluble solid acid is preferably used. By using a foaming aid composed of a water-soluble solid acid in combination with a foaming agent, foaming of the solid flocculant dropped in water is promoted, and as a result, the disintegration time of the tablet is greatly shortened.

  Although the water-soluble solid acid is not particularly limited, for example, citric acid, succinic acid, fumaric acid, maleic acid, tartaric acid, oxalic acid, malic acid, adipic acid, sodium dihydrogen phosphate, boric acid, potassium dihydrogen phosphate, Etc. These water-soluble solid acids may be used alone or in combination of two or more. The blending amount of the foaming agent and the foaming aid can be added by any formulation, but usually 10 to 150 parts by weight of the foaming aid is added to 100 parts by weight of the foaming agent. If the amount of foaming aid is less than this amount, it is difficult to obtain a sufficient foaming assistance effect, and if it is too much, moisture in the air tends to be absorbed and foaming may occur before use. It will become something.

In the foamable solid aggregating agent for water treatment of the present invention, a molding aid is used in order to solidify and maintain its shape. The present invention is characterized in that calcium silicate is selected and used among a number of molding aids. That is, calcium silicate is essential as the molding aid, and among these calcium silicates, a gyrolite type crystal structure, that is, 2CaO · 3SiO ₂ · nSiO ₂ · mH ₂ O (where n and m are positive numbers). And having an SiO ₂ / CaO molar ratio of 1.6 to 4.2 and having an average particle size of 100 μm or less only has an effect as a molding aid even if the addition amount is small. In particular, the molding pressure is particularly preferable because molding can be performed at a low pressure.

  This calcium silicate having a gyrolite-type crystal structure can be confirmed by taking a photomicrograph and has a petal-like structure whose shape resembles a rose petal. It is marketed under the product name “Made by Tokuyama Corporation”. This calcium silicate having a petal-like crystal structure is excellent in liquid absorbency and can take in moisture contained in the solid flocculant, and can stabilize components such as gypsum that is particularly sensitive to moisture. Therefore, it is a very preferable molding aid.

  As the addition amount of calcium silicate, 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight is added to 100 parts by weight of the total of the water treatment flocculant and the foaming agent. preferable. If the addition amount is less than this range, solidification becomes difficult, and if it is too much, not only the disintegration property in water is lowered, but also it becomes expensive.

  The foamable solid flocculant for water treatment of the present invention may contain an auxiliary agent such as a lubricant and a stabilizer for the flocculant component, as long as the performance is not impaired. Also good. Examples of the lubricant include magnesium stearate, calcium stearate, zinc stearate, stearic acid, talc, hydrogenated vegetable oil, talc and the like, and magnesium stearate and calcium stearate are preferable.

  The foamable solid aggregating agent for water treatment of the present invention must be solid, but the form may be either a granulated product or a tablet. Examples of the solidification method of the foamable solid flocculant for water treatment of the present invention include a rolling granulation method, a compression granulation method, a stirring granulation method, an extrusion granulation method, and a crushing granulation method. When the inorganic coagulant and organic coagulant are mixed in the coagulant component, or when components such as gypsum are included, the storage stability of the coagulant is reduced and the coagulation site is deactivated. In order to avoid this, it is preferable to use a dry granulation method. In the case of producing a tablet, it is possible not only to directly compress tablets but also to tablet once granulated using the granulation method described above.

  As a method of using the foamable solid flocculant for water treatment, a generally used method is used without any limitation. For example, it is also possible to use a feeder in which tablets made in a disk shape are put in a state where a plurality of tablets are stacked in a cylinder, and the tablets are automatically dropped into water one by one at regular intervals. In this case, a phenomenon such as shelf hanging does not occur, and supply with an inexpensive device is possible. In addition, it may be possible to pack tablets one by one in bags and store them in mud or other places where it is difficult to secure drinking water overseas and use the supernatant as drinking water. Furthermore, in order to drop in a wide area such as a pond or a lake, a method of producing a solid material in a cannonball shape and driving it with a bazooka cannon is considered. In this case, the target solid is obtained by solidification using a spherical granulator.

  When coagulating using the foamable coagulant for water treatment of the present invention, the necessary equipment is not only a method of stirring sewage or sludge and coagulating sedimentation agent using a stirring blade in a water tank, A method of stirring by passing a spiral line, a submersible pump, a submersible jet pump, a sludge suction vehicle, etc. are conceivable. In particular, the foamable solid aggregating agent for water treatment of the present invention is an epoch-making invention that can be used with simple equipment as compared with the conventional one and can greatly reduce the equipment burden.

Example 1
Obtain the following commercially available water treatment flocculants and mix sodium hydrogen carbonate as a foaming agent and calcium silicate having a petal-like crystal structure as a molding aid (product name: Florite, manufactured by Tokuyama Corporation). Molding was performed under pressure to obtain a foamable solid flocculant for water treatment.
Commercially available flocculant 1 “Product name: ZEO Flock” Gypsum-based flocculant manufactured by Eco-Rikagaku Co., Ltd. Commercially available flocculant 2 “Product name: Aquafloc SL” artificial zeolite flocculant (manufactured by Suzuki Sangyo Co., Ltd.)
Commercial flocculant 3 “Product name: WIT grinder” Flour ash-based flocculant (WIT Co., Ltd.)
(Fly ash 40%, calcium sulfate 10%)
Commercial flocculant 4 “Product name: Kiyomaru-kun” Flocculant composed mainly of inorganic matter derived from volcanic ash (manufactured by Yagyu Waterproof Engineering Co., Ltd.)
Commercial flocculant 5 “Product name: Mizumu” artificial zeolite flocculant (ISAA Co., Ltd.)
Commercial flocculant 6 “Product name: Hyper Flock” polymer and flocculant of inorganic main component (commercial flocculant 7 manufactured by Hosho EG Co., Ltd. “Product name: Biwako instantaneous flocculant (sample)” Cement & artificial zeolite flocculant ( Toa Industries Co., Ltd.)
The tablets obtained were evaluated for disintegration in water and aggregating ability according to the following criteria. The results are shown in Table 1.

1. Presence / absence of tableting After applying pressure at 40 to 120 kg / cm ² for 1 minute using a cylinder-type pressurizing apparatus, a sample was taken out and checked for tableting.
○ mark: It becomes a tablet and does not break even if it is held by hand.
X mark: The powder is not tableted and collapses when taken out.

2. Observation of disintegration in water The above-mentioned solid aggregating agent for water treatment was put into a glass sample bottle containing 20 ml of water, and the state in which the tablet disintegrated was observed while still standing.
Mark: foams immediately after being put into water, and moves up and down in water quickly. Collapses quickly: foaming starts immediately after being thrown into water, and collapses within a few minutes. After a while, the collapse begins slowly.
X mark: Even if thrown into water, it does not foam and does not collapse for a long time.

3. 1 g of bentonite is added to and suspended in a PET bottle containing 100 ml of water with agglomeration capacity for sewage, and 0.1 g of the above-mentioned solid aggregating agent for water treatment is added to this suspension and vigorously stirred for 30 seconds. The situation was observed.
◎: Flock is generated after a few minutes after standing, and the supernatant is also transparent.
Mark: Flock is formed after several minutes of standing, but the supernatant is slightly opaque.
Mark: Small flocs form after a while, but settling is slow.
X mark: No flocs are generated even when left standing.

Example 2
After adjusting the composition shown in Table 2 instead of Example 1 as a flocculant for water treatment, using sodium bicarbonate as a foaming agent and fluorite as a molding aid, and molding at a tableting pressure of 40 kg / cm ² The presence / absence of tableting, disintegration, and aggregation performance were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1
Table 3 shows the evaluation results when no molding aid or foaming agent was used for No1 of Example 1.

  As is clear from Table 3, when fluorite (calcium silicate) was not used as a molding aid, the flocculant could not be tableted, and as a result, the disintegration of the tablet could not be evaluated. On the other hand, the cohesiveness of the powder before tableting was examined, but it was not inferior to that of the flocculant alone. Further, when fluorite was used as a coagulant forming aid, it could be tableted, but when no foaming agent (alkali carbonate) was used, disintegration was insufficient. When polyvinyl pyrrolidone was used as a water-soluble polymer or potassium chloride was used as a water-soluble salt in order to disintegrate the flocculant in water, tableting was possible but disintegration was insufficient. As a result, the cohesiveness was also insufficient.

  This has the effect of flocculating the flocculant and the foaming agent when tableting due to the fact that florite has a petal-like crystal structure. It is thought to be separated. Furthermore, carbonate foams in water, so it has the effect of rapidly disintegrating and dispersing the coagulant aid, while water-soluble polymers and water-soluble salts take time to dissolve in water. Moreover, it is considered that the disintegrating property of the flocculant was insufficient due to the lack of foamability.

Comparative Example 2
Commercially available flocculant 1 used in Example 1 as a water treatment flocculant, sodium hydrogen carbonate as a foaming agent, and crystalline cellulose (product name Theolas FC-30, manufactured by Asahi Kasei Kogyo Co., Ltd.) instead of fluorite as a molding aid , Presence or absence of tableting, disintegration, and aggregation performance when using anhydrous calcium hydrogen phosphate (product name: Fujicalin, manufactured by Fuji Chemical Industry Co., Ltd.), magnesium metasilicate magnesium aluminate (product name: Neusilin, manufactured by Fuji Chemical Industry Co., Ltd.) Evaluation was performed in the same manner as in Example 1. The results are shown in Table 4.

  As is apparent from Table 4, crystalline cellulose, anhydrous sodium hydrogen phosphate or magnesium aluminate metasilicate, which is known as an excipient, is used instead of fluorite (calcium silicate) as a coagulant forming aid. In this case, at the time of molding at a relatively low pressure, the tablet could not be formed even if the addition amount was increased to 25% by weight. The reason for this is not clear, but because the fluorite has a petal-like crystalline structure as in the results of Table 3, it has an excellent effect of holding together the flocculant and the foaming agent when tableting. It is considered a thing.

Claims (6)

  Contains 50 to 90 parts by weight of a water treatment flocculant, 50 to 10 parts by weight of a foaming agent, and 0.1 to 20 parts by weight of calcium silicate (the total amount of the water treatment flocculant and the foaming agent is 100 parts by weight). A foamable solid flocculant for water treatment, characterized in that   The foaming solid aggregating agent for water treatment according to claim 1, wherein the foaming adjuvant is contained in an amount of 10 to 150 parts by weight per 100 parts by weight of the foaming agent.   3. The foamable solid aggregating agent for water treatment according to claim 1, wherein the aggregating agent for water treatment is a powdery aggregating agent mainly composed of an inorganic substance.   3. The foamable solid flocculant for water treatment according to claim 1 or 2, wherein the flocculant for water treatment is a flocculant mainly composed of at least one of gypsum, cement or zeolite.   The foaming solid flocculant for water treatment according to claim 1 or 2, wherein the foaming agent is an alkali carbonate. The foamable solid flocculant for water treatment according to claim 1 or 2, wherein the calcium silicate is calcium silicate having a petal-like structure.