JP2006102705A - Cement draining sheet and cement draining treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement draining sheet capable of easily treating cement drain at a low cost and constituted so as to prevent environmental pollution, and a cement draining treatment method. <P>SOLUTION: The cement draining sheet is equipped with a citric acid powder 3 for adjusting the pH of cement drain and a pair of spun-bond nonwoven fabrics 2a and 2b for holding and supporting the powder and, when the cement drain is passed through the cement draining sheet, citric acid is dissolved to adjust the pH of the cement drain. Further, in the cement draining treatment method, the amount of citric acid necessary for adjusting the pH of the cement drain is calculated and the cement draining sheets 1 capable of supplying the necessary amount of citric acid are stacked and the cement drain is passed through these draining sheets 1 to be adjusted in its pH. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cement drainage sheet capable of supplying a room temperature solid organic acid such as citric acid necessary for pH adjustment of cement wastewater, and a cement wastewater treatment method using the cement drainage sheet.

  Conventionally, sandblasting, steel shot, and vacuum blasting have been performed in concrete structures such as piers for seismic reinforcement work in order to increase the adhesion of existing concrete surfaces. Recently, cutting (scratching) and surface treatment using a water jet have been performed (see Patent Document 1). The use water (cement drainage) including the scouring waste by high-pressure water injection of such a concrete structure generally shows a high alkalinity of pH 12 or more, and if it is drained as it is, it gives a load to the environment.

  Similarly, in order to remove dirt attached to the surface of concrete walls, concrete piers, concrete fences, outer walls of houses, floors, window glass, etc. using jets (high pressure water jets) There is also a cleaning method that removes dirt by scraping. However, such a cleaning method tends to cause unevenness due to scratches on the solid cleaning surface. And the water used for this washing | cleaning also shows high alkalinity. Then, if it is going to process with an acidic chemical | medical agent instead of high pressure water injection, the solid surface will melt | dissolve or damage, and will cause a crack etc. Therefore, chemical cleaning with chemicals is not substantially performed. In order to solve this problem, a cleaning method has been proposed in which a cleaning liquid containing a compound that generates gas is inserted between the solid surface and the dirt adhering thereto, and gas is generated on the spot to remove the dirt. (See Patent Document 2). As the compound that generates gas, peroxycarbonate or peroxyborate, or carbonate or bicarbonate that generates carbon dioxide is used.

JP 2003-311691 A JP-A-10-88190

  The construction by the water jet etc. of the patent document 1 demonstrated above collects the cleaning waste and use water discharged | emitted by cutting and surface treatment by vacuum suction, and adds PH adjusters etc. to use water collectively. Can be neutralized. As a result, it is possible to reduce the load on the construction site environment that has been conventionally performed.

  However, the technique of Patent Document 1 requires a special water jet and a special waste water treatment facility, and such treatment can be performed only in a large-scale construction both in terms of cost and technology. It is practically difficult to use such a technique for construction of scale. Therefore, there is a demand for means capable of performing solid content filtration and pH treatment from used wastewater easily and inexpensively even at the site of small and medium scale construction.

  Moreover, since the technique of patent document 2 peels and removes dirt from a solid surface with gas, it cannot be used in cutting or surface treatment with a water jet. Since peroxycarbonate, peroxyborate, carbonate or bicarbonate is drained, there is a possibility that the drainage will contaminate the work environment.

  In addition, when there are fishing grounds such as seas, rivers, lakes, etc. near the bridge construction site, contaminated cement wastewater flows into the fishing grounds, and fine scouring waste and high alkaline wastewater diffuse into the fishing grounds. The fishermen are keenly hoped that the cement wastewater will be sufficiently treated and drained at the construction site. Recently, there have been reports of cases where cement drainage is applied to cars traveling near the piers of bridge construction and repainting, and there is a great expectation for on-site treatment of cement wastewater.

  Then, in order to solve such a subject, an object of this invention is to provide the cement waste_water | drain sheet | seat which can process and drain a cement waste_water | drain easily at low cost, and does not pollute the environment.

  Another object of the present invention is to provide a cement wastewater treatment method that can easily treat and drain cement wastewater at low cost and does not pollute the environment.

  The cement drainage sheet of the present invention comprises a room temperature solid organic acid powder for adjusting the pH of the cement drainage and a pair of spunbond nonwoven fabrics that uniformly distribute the powder and carry it from both sides. When this is done, the normal temperature solid organic acid dissolves and the pH of the cement wastewater is adjusted.

  According to the present invention, cement wastewater can be easily treated and drained at low cost, and the environment is not polluted.

  A first aspect of the present invention includes a room temperature solid organic acid powder for adjusting the pH of cement wastewater, and a pair of spunbond nonwoven fabrics that uniformly distribute the powder and support the wastewater from both sides. A cement drainage sheet that adjusts the pH of the cement drainage by dissolving the room temperature solid organic acid when it is watered. By supplying in the form of the number of layers and passing through the cement drainage sheet once or repeatedly, the solid content filtration with the spunbond nonwoven fabric and the pH adjustment with the room temperature solid organic acid powder can be performed easily and at low cost. The room temperature solid organic acid is an organic acid that solidifies at room temperature, and there are many materials that are also used as foods such as citric acid. This adjusts the pH and drains it after filtration, so it does not pollute the environment. Here, pH adjustment means adjusting pH for neutralization in consideration of neutralization treatment and the neutralization action of soil.

  A second form of the present invention is a form subordinate to the first form, wherein the room temperature solid organic acid is a cement drainage sheet which is a powder of citric acid having a particle size of 10 μm to 2000 μm, and citric acid is contained in the cement drainage. It can be easily dissolved to adjust pH.

A third aspect of the present invention is in a form dependent on the first or second embodiment, the cement drainage room temperature the solid organic acid is supported on a spunbond nonwoven fabric at a rate of 20g / m ² ~500g / m ² sheet The pH of the cement wastewater can be adjusted by simply laminating one to three cement drainage sheets.

  The fourth form of the present invention is a form subordinate to any one of the first to third forms, and a normal temperature solid organic acid amount necessary for adjusting the pH of the cement wastewater is supported on the spunbond nonwoven fabric. It is an integer multiple of or approximately an integer multiple of room temperature solid organic acid. If this is an integer greater than 1, it is a cement drainage sheet that is laminated and used. It can be supplied by laminating cement drainage sheets.

  A fifth aspect of the present invention is a form subordinate to any one of the first to fourth aspects, in which the spunbond nonwoven fabric supports the powder and is 0.1 mm for filtering solids in the cement waste water. It is a cement drainage sheet having a thickness of 3 mm and a porosity of 75% to 95%, and the solid content in the cement drainage can be filtered by a spunbond nonwoven fabric.

  In the sixth aspect of the present invention, the amount of room temperature solid organic acid necessary for adjusting the pH of the cement waste water is obtained, and a number of laminated layers of cement waste water sheets capable of supplying the amount of room temperature solid organic acid are laminated. This is a cement wastewater treatment method in which the pH is adjusted by passing water, and the required amount of room temperature solid organic acid is supplied in the form of a cement drainage sheet carrying the room temperature solid organic acid and its number of layers. The pH can be adjusted easily and at low cost by passing the resin repeatedly or repeatedly. The room-temperature solid organic acid powder is often used as a food, such as citric acid, and the pH is adjusted by this and drained after filtration, so it does not pollute the environment.

  7th form of this invention is a form subordinate to 6th form, Comprising: It is a cement waste water treatment method by which the cement waste water sheet of any one of the 1st-5th form is laminated | stacked, It filters with a spun bond nonwoven fabric The cement waste water can be easily treated at low cost because it carries the normal temperature solid organic acid powder.

  The eighth form of the present invention is a form subordinate to the sixth or seventh form, wherein a main filter for filtering a solid content having a particle size of 20 μm to 2000 μm is laminated together with a cement drainage sheet, and cement is added thereto. The cement wastewater treatment method according to claim 6 or 7, wherein the pH is adjusted by passing the wastewater, and in addition to adjusting the pH of the cement wastewater, the cement wastewater is filtered to a solid content having a particle size of 20 µm to 2000 µm. And can not pollute the environment.

  The cement waste water sheet and the cement waste water treatment method of Example 1 of the present invention will be described based on the drawings. The present invention is a conventional method in which a plurality of cold waste organic acid-carrying cement drainage sheets are laminated or folded, pH is adjusted by allowing cement wastewater to permeate in this state, and solid content in cement wastewater is also filtered. The present invention provides a cement wastewater treatment method with a new concept that is not present, and also provides a cement wastewater sheet used for that purpose.

  Since the cement waste water containing the scouring waste is highly alkaline and contains a solid content, the conventional waste water treatment is neutralized by adding a pH adjuster, and the solid content is filtered. However, in such wastewater treatment, wastewater is collectively neutralized using chemicals, so facilities for wastewater treatment are necessary, and it is carried out at high costs at small and medium-scale construction sites. There were many problems. For this reason, this invention provides the means of the new cement waste water treatment which does not give load to an environment.

  1 (a) is a sectional view of the cement drainage sheet in Example 1 of the present invention, FIG. 1 (b) is a partially broken perspective view of the cement drainage sheet of (a), and FIG. 2 is the amount of citric acid added. FIG. 3 is a diagram showing the manufacturing process of the cement drainage sheet in Example 1 of the present invention, and FIG. 4A shows only a plurality of cement drainage sheets in Example 1 of the present invention. FIG. 4B is an explanatory diagram for using the cement drainage sheet in the first embodiment of the present invention in a folded manner, and FIG. 5A is a diagram after the cement drainage sheet in the first embodiment of the present invention. FIG. 5B is an explanatory view in which the cement drainage sheet in Example 1 of the present invention is provided after the filter.

  1 (a) and 1 (b), reference numeral 1 denotes a cement drainage sheet for treating cement drainage discharged when high-pressure water is injected into a concrete structure, and 2a and 2b are spunbond nonwoven fabrics constituting the cement drainage sheet 1. . The spunbonded nonwoven fabrics 2a and 2b are made of fibers such as PP (polypropylene) and PET (polyester) which are melted directly from the tip of the nozzle and spun and collected into a sheet by collecting and collecting fibers without weaving them. It is a nonwoven fabric bonded together. The spunbond nonwoven fabrics 2a and 2b have a so-called porous structure, and are used for sanitary materials such as paper diapers, surgical caps, masks, agricultural materials, roofing materials, clothing interlinings, civil engineering / building materials.

Next, 3 is a citric acid powder having a particle size of citric acid of about 10 μm to 2000 μm, preferably 20 μm to 500 μm. This citric acid is the room temperature solid organic acid of the present invention in Example 1. In general, organic acids often show weaker acidity than inorganic acids, but the citric acid powder of Example 1 is weakly acidic and shows high safety to the environment. . As described above, the room temperature solid organic acid of the present invention is not particularly limited as long as it shows weak acidity among many organic acids such as citric acid, acetic acid, malic acid, and is solidified at room temperature and easily dissolved in water. In addition, an organic acid mixed with another auxiliary material and solidified may be used as long as it is an auxiliary material that does not give a load to the environment when it is dissolved. Some inorganic salts exhibit an action close to that of a room-temperature solid organic acid, but an organic acid is more preferable in view of environmental load and surrounding security. Citric acid powder 3 of Example 1, in the state is related with the particle ^size, 20 g / m 2 to 500 g / ^{m 2,} the amount of powder of ^50g / ^{m 2 ~300g} / m 2 if it is distributed uniformly, 2 A sheet of spunbonded nonwoven fabric 2a, 2b is sandwiched and supported from both sides. Thereby, at the water temperature at many work sites, citric acid dissolves in the cement waste water with a solubility of 60 g / 100 g to 70 g / 100 g, and neutralizes it. The solubility of citric acid is 60 g / 100 g at a water temperature of 20 ° C., 70 g / 100 g at 50 ° C., and 78 g / 100 g at 60 ° C.

  Here, the carrying of the room temperature solid organic acid will be described. In Example 1, the spunbond as a carrier from both sides of the uniformly distributed citric acid powder 3 (in normal use, it is vertical due to gravity in use). It is sandwiched between the nonwoven fabrics 2a and 2b, and the entire surface is fixed with a binder. Thereby, the citric acid powder 3 is fixed, and the citric acid powder 3 does not spill out from the cement drainage sheet 1. The same applies to other room-temperature solid organic acids. In Example 1, a polyethylene adhesive is used as the binder, and PP (polypropylene) is used as the spunbonded nonwoven fabrics 2a and 2b. In the case of Example 1, since all are olefins and the cement drainage sheet 1 does not contain a load chemical substance, even if it is finally incinerated, there is no load on the environment. Processing becomes easy.

By the way, when the particle size of the citric acid powder 3 is made too small, dissolution for neutralization becomes easy, but it becomes too fine and the spunbonded nonwoven fabrics 2a and 2b are difficult to carry. Therefore, in Example 1, the particle size of the citric acid powder 3 is about 10 μm to 2000 μm. This provides a sufficient dissolution rate. Then, this for carrying citric acid powder 3 uniformly distributed has a particle size, for example, long fibers ^{500g / m 2 ~1000g / m 2} , 0.1mm~3mm thickness, porosity 75% and 95 % Of, for example, polypropylene spunbond nonwoven fabrics 2a and 2b. In Example 1, the citric acid powder 3 having a particle diameter of 20 μm is made of spunbonded nonwoven fabrics 2a and 2b of polypropylene long fibers having a thickness of 800 g / m ² , 2.6 mm and a porosity of 90%. Thereby, the citric acid powder 3 which is a fine powder is easily dissolved in the cement drainage that permeates the cement drainage sheet 1, and the porous structure of the spunbond nonwoven fabrics 2a and 2b filters the solid content in the cement drainage. Can do.

Next, pH adjustment with citric acid, which is a room temperature solid organic acid of Example 1, will be described. Here, the pH adjustment of the present invention means a neutralization treatment for adjusting to pH 7 and a treatment for adjusting to a predetermined pH close to pH 7 for neutralization in consideration of the neutralizing action of soil. The latter will be described later. FIG. 2 shows the relationship between the amount of citric acid added, the cement waste water after neutralization, and the pH. This is obtained by neutralizing 50 mL of cement wastewater with a 0.2 wt% citric acid solution and converting it to 100 L of cement wastewater (results of three experiments). The cement wastewater has a maximum pH of about 12.5 according to many measurements, and the cement wastewater in FIG. 2 also shows a pH of 12.5 when untreated. According to FIG. 2, when neutralizing 100 L of this cement waste water with citric acid, 230 g / m ² of citric acid is required. Therefore, in the case of the cement drainage sheet 1 in which the amount of the citric acid powder 3 is supported by 230 g / m ² , the cement drainage can be neutralized by simply passing through one cement drainage sheet 1, and 120 g / m ^{2 is} supported. In this case, it is understood that approximately two cement drainage sheets 1 may be allowed to pass, and even when 75 g / m ^{2 is} supported, approximately three cement drainage sheets 1 may be allowed to pass.

Thus, when citric acid content carried on a cement drainage sheet 1 is 230 g / m ^2, equal to the citric acid amount necessary to neutralize the cement drainage, as through one cement drainage sheet 1 It can be neutralized by water, but when the amount of citric acid carried on the cement drainage sheet 1 is 120 g / m ² or 75 g / m ² , it is approximately an integer multiple. It can be seen that neutralization can be achieved by passing water.

As shown in FIG. 2, the amount of citric acid when the pH is lowered from pH 12.5 to pH 10 is greatly different from the amount of citric acid when the pH is lowered from pH 10 to pH 7. The amount of citric acid in the former is 200 g / m ² , while the amount of citric acid in the latter is 20 g / m ^{2 to} 30 g / m ² , and it is lowered from pH 10 to pH 7 with only slight neutralization. Can do. And the soil also has an adsorption action and neutralization ability, and neutralization at pH 10 or less can be sufficiently performed by the self-cleaning ability of the soil. Therefore, even when draining at pH 10, the load on the environment is very small. Considering the action of the soil in this way, it is possible to drain at pH 10. In this case, since the required amount of citric acid is 200 g / m ² , the amount of citric acid carried on the cement drain sheet 1 is 200 g / m ^2. When 100 g / m ² or 70 g / m ^{2 is set} , the integral multiple or the approximate integral multiple is obtained, and if one or a plurality of layers are laminated and cement wastewater is passed through, pH can be adjusted and neutralization can be performed.

  Then, the manufacturing process of the cement waste_water | drain sheet | seat of Example 1 is demonstrated easily based on FIG. In FIG. 3, 10 is a spraying device for spraying the spunbond nonwoven fabric 2b with a container containing the citric acid powder 3 which is a room temperature solid organic acid of Example 1, and 11 is a spraying device formed in plural on the spraying device 10. It is an opening. As described above, the room temperature solid organic acid is not limited to citric acid. The spraying opening 11 is opened so that the citric acid powder 3 is sprayed uniformly. Next, 20a and 20b are spunbond nonwoven fabric wound bodies obtained by winding the spunbond nonwoven fabrics 2a and 2b, respectively. In addition, evenly spraying means that at least the part that is allowed to pass water is sprayed uniformly, and even if processing such as reducing the spraying amount is applied to the part that is not reliably passed water, etc. Good.

As shown at the left end of FIG. 3, the spunbond nonwoven fabric 2 b is drawn out from the spunbond nonwoven fabric wound body 20 b around which the spunbond nonwoven fabric 2 b is wound, and passed under the center spraying device 10. In the spraying device 10, the citric acid powder 3 is sprayed uniformly from the spray opening 11 on the spunbond nonwoven fabric 2b. A spunbond nonwoven fabric wrapping body 20a is disposed behind the sprinkler 10 (right half of FIG. 3), and the spunbond nonwoven fabric 2b is fed in a state in which the citric acid powder 3 is uniformly sprinkled. The spunbond nonwoven fabric 2a drawn from the bonded nonwoven fabric wound body 20a is stacked. Then small weights applied to spunbonded nonwoven 2a, 2b citric acid supported on, it is then cut to be shaped for example, 1 m ² through 10m ² units. Thereby, the cement drainage sheet 1 in a state where the powdered citric acid powder 3 is uniformly distributed between the spunbonded nonwoven fabrics 2a and 2b is formed. The amount of the citric acid powder 3 is basically controlled by the number and diameter of the spray openings 11 but can be finely adjusted by controlling the winding speed of the spunbond nonwoven fabrics 2a and 2b. Moreover, if the spunbond nonwoven fabric wound bodies 20a and 20b are exchanged for various specifications, the specifications of the spunbond nonwoven fabrics 2a and 2b can be freely changed.

By the way, the prices of the spunbond nonwoven fabrics 2a and 2b and the citric acid powder 3 are relatively low, and the cement drainage sheet 1 using them can be manufactured at a low price. Depending on the amount of discharged cement wastewater, in the case of small-scale construction, one site of 1m ^{2 to} 10m ² or several cement drainage sheets 1 are laid on one site, and each cement wastewater may be further removed depending on the case. By stacking cement drainage sheets on the sheet 1 and draining the cement drainage through the cement drainage, it is possible to neutralize the highly alkaline cement drainage. There is no need to provide equipment for processing.

  The cement wastewater treatment method of Example 1 in which filtration and pH adjustment with citric acid are performed using the cement wastewater sheet 1 of Example 1 described above will be described. The usage method of the first cement drainage sheet 1 is a usage method of adjusting pH and filtering cement wastewater using only the cement drainage sheet 1. The filtration with the cement drainage sheet 1 is basically a coarse filtration for filtering a particle size of 100 μm to 2000 m or more, and when the size of the particles of the cleaning waste contained in the cement drainage is not so small, or the filtration is not so much This is an effective method when it does not matter. In this case, the thickness and porosity of the spunbond nonwoven fabrics 2a and 2b are set as low as possible in order to filter the solid content of the scouring waste contained in the cement wastewater as much as possible with the spunbond nonwoven fabrics 2a and 2b. It is good to do.

  In this case, as shown in FIG. 4 (a), two or more cement drainage sheets 1 are laminated to flow cement drainage, or the cement drainage sheet 1 is folded in half or more as shown in FIG. 4 (b). Used by folding it (not shown). A combination of lamination and folding is also possible. By laminating the cement drainage sheet 1 in this way, two or three or more spunbond nonwoven fabrics 2a and 2b sandwiching the citric acid powder 3 are folded into a spunbond nonwoven fabric 2a, a layer of citric acid powder 3, and a span. Bonded nonwoven fabric 2b, spunbond nonwoven fabric 2b, layer of citric acid powder 3, spunbond nonwoven fabric 2a,... , 2b, 2a,..., Citric acid is dissolved in the two layers of citric acid powder 3, 3,. However, three or more cement drainage sheets 1 can be laminated. However, since it is advantageous in cost to laminate two sheets, it is preferable to laminate two sheets.

  In the used cement drainage sheet 1, the citric acid powder 3 is dissolved and consumed, but the spunbonded nonwoven fabrics 2a and 2b are clogged with solids, and the fluid resistance is high and the mesh is apparently small. It has become. Therefore, by laminating this used cement drainage sheet 1 on the upstream side of the unused cement drainage sheet 1, it is possible to effectively use the used cement drainage sheet 1 and improve the solids filtration capacity. it can.

The second method of use is to separately provide a main filter for filtering the solid content as shown in FIG. 5 (a), and adjusting the pH of the waste water after the solid content is filtered by the cement drain sheet 1 To do. In FIG. 5A, 4 is a main filter arranged separately from the cement drainage sheet 1. The main filter 4 of Example 1 uses a filter medium (FC-525 manufactured by Nippon Vilene Co., Ltd.) having a thickness of 800 g / m ² , 2.6 mm and a porosity of 91.8% in order to remove a solid content of about 25 μm. Yes.

  The spunbonded nonwoven fabrics 2a and 2b are not suitable in terms of carrying and dissolving functions if the porous mesh is made too fine, so the mesh has limitations and the filtration capacity also has a lower limit. For this reason, when filtering to a solid content having a particle size of 20 μm to 100 μm, it is preferable to provide a main filter 4 separately. Therefore, in the second usage method, the main filter 4 is arranged on the cement drainage sheet 1 (upstream side). According to this method, since the pH is adjusted after removing the solid content with the main filter 4, citric acid is not wasted, and unevenness in neutralization depending on the position does not occur. In addition, the cement drainage sheet 1 of Example 1 can visually check the situation where citric acid is dissolved, but in the case of severe contamination of the cement drainage, this dissolved situation becomes invisible. When the main filter 4 is used as in the second usage method, the cement drainage sheet 1 is passed through after being filtered by the main filter 4, and dissolution of citric acid can be visually confirmed.

  The main filter 4 is more expensive than the spunbonded nonwoven fabrics 2a and 2b for filtering 20 μm to 100 μm, and it is desirable to prevent clogging as much as possible. Therefore, a method of using the used cement drainage sheet 1 on the main filter 4 and preliminarily filtering is preferable.

Next, as shown in FIG. 5 (b), the third method of use is to adjust the pH of the cement wastewater with the cement drainage sheet 1 and perform preliminary filtration, and then to adjust the solid content after the pH adjustment and preliminary filtration. This is a method of full-scale filtration with the main filter. Since the main filter 4 in this case also removes a solid content of about 25 μm in Example 1, a filter medium having a thickness of 800 g / m ² , 2.6 mm thickness and a porosity of 91.8% (FC-525 manufactured by Nippon Vilene Co., Ltd.) Is used.

  After the preliminary filtration with the spunbond nonwoven fabrics 2a and 2b, the fine solid content of 20 μm to 100 μm is filtered with the main filter 4, so that the clogging of the main filter 4 can be delayed as much as possible. The main filter 4 is more expensive than the cement drainage sheet 1 because it is finely filtered. However, preliminary filtration with the spunbond nonwoven fabrics 2a and 2b can reduce the cost of drainage.

  In addition to this, the cement drainage sheet 1 may be disposed under the main filter 4. Further, the used cement drainage sheet 1 may be further stacked on the cement drainage sheet 1.

  As described above, the cement drainage sheet and the cement drainage treatment method of Example 1 do not collect the wastewater collectively and physically and chemically adjust and filter the wastewater as in the conventional wastewater treatment of cement wastewater. By passing water through a cement drainage sheet carrying a room temperature solid organic acid such as an acid as many times as necessary, that is, passing through the number of layers of a room temperature solid organic acid powder and a spunbond nonwoven fabric, the pH can be adjusted easily. Filtration is performed. Accordingly, it is not necessary to install a wastewater treatment facility, and pH can be easily adjusted even in small and medium-scale construction, considering the neutralization ability of the cement wastewater sheet from the amount of wastewater at the work site. In addition, cement drainage treatment that does not place a burden on the environment can be realized simply by using a cement drainage sheet.

  The present invention can be applied to cement wastewater treatment when a concrete structure is cut or surface-treated with a water jet or the like.

(A) Sectional view of the cement drainage sheet in Example 1 of the present invention, (b) Partially broken perspective view of the cement drainage sheet of (a) Relationship between the amount of citric acid added, cement wastewater after neutralization, and pH Manufacturing process diagram of cement drainage sheet in Example 1 of the present invention (A) Explanatory drawing using only a plurality of cement drainage sheets in Example 1 of the present invention, (b) Explanatory diagram using folded cement drainage sheets in Example 1 of the present invention. (A) Explanatory drawing which provided the filter after the cement drainage sheet in Example 1 of this invention, (b) Explanatory drawing which provided the cement drainage sheet in Example 1 of this invention behind the filter

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cement drainage sheet 2a, 2b Spunbond nonwoven fabric 3 Citric acid powder 4 Main filter 10 Spraying device 11 Spraying opening 20a, 20b Spunbond nonwoven fabric winding body

Claims (8)

A normal temperature solid organic acid powder for adjusting pH of cement wastewater, and a pair of spunbond nonwoven fabrics that uniformly distribute the powder and carry from both sides, and when the cement wastewater is passed through, the normal temperature A cement drainage sheet, wherein a solid organic acid dissolves and the pH of the cement drainage is adjusted. The cement drainage sheet according to claim 1, wherein the room temperature solid organic acid is a citric acid powder having a particle size of 10 µm to 2000 µm. Cement drainage sheet as claimed in claim 1 or 2, wherein the solid state at room temperature the organic acid is supported on the spunbonded nonwoven fabric at a rate of ^{20g / m 2 ~500g / m 2} . The amount of room temperature solid organic acid required to adjust the pH of the cement waste water is an integer multiple or substantially an integer multiple of the amount of room temperature solid organic acid supported on the spunbonded nonwoven fabric. The cement drainage sheet according to any one of claims 1 to 3, wherein the cement drainage sheet is used. The spunbonded nonwoven fabric has a thickness of 0.1 mm to 3 mm and a porosity of 75% to 95% in order to carry the powder and filter solids in cement wastewater. The cement drainage sheet in any one of -4. Cement drainage that obtains the amount of room temperature solid organic acid necessary for pH adjustment of cement wastewater, laminates cement drainage sheets with the number of layers that can supply the amount of room temperature solid organic acid, and adjusts pH by passing cement wastewater through Processing method. The cement waste water treatment method according to claim 6, wherein the cement waste water sheets according to any one of claims 1 to 5 are laminated. The cement wastewater treatment method according to claim 6 or 7, wherein a main filter for filtering a solid content having a particle diameter of 20 µm to 2000 µm is laminated together with the cement wastewater sheet, and the pH is adjusted by passing cement wastewater therethrough.

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