JPH078969A - Treatment of muddy water - Google Patents

Abstract

PURPOSE:To facilitate the transportation of muddy water by removing the moisture of muddy water to reduce the volume of the muddy water by adding natural gum and a baron compd. to the muddy water to flocculate solid components to separate and remove moisture. CONSTITUTION:A natural gum aq. soln. 9 is supplied to muddy water 6 to be mixed therewith in a line mixer 2 and a boron compd. aq. soln., for example, a sodium borate aq. soln. 11 is further mixed with muddy water in the line mixer 2 and water 14 is mixed with the resulting mixed soln. to form a diluted mixed soln. which is, in turn, supplied to a reaction tank 3 equipped with a stirrer 3a. The mixed soln. sufficiently stirred in the reaction tank 3 is subjected to the formation of a rubbery elastic gel or division due to the boron compd. to finally form a granular sold 15. Next, the treated soln. containing the granular solid 15 is discharged from the upper part of the reaction tank 3 to be allowed to flow out to a vibration screen 4 vibrated by a motor. Moisture containing no earth and sand passing through the meshes of the vibration screen 4 is discharged and the granular solid from which moisture is removed is recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating mud water for removing water in the mud water to significantly reduce the volume and facilitate transportation. More specifically, muddy water of various properties,
The present invention relates to a method for treating muddy water, which forms a large and hard floc by a simple operation, separates it from water and removes it, and significantly reduces the volume of muddy water to facilitate transportation.

[0002]

2. Description of the Related Art Conventionally, shield construction method in tunnel construction such as subway, mud discharged in well drilling construction in oil fields and hot springs, mud discharged by pile construction construction such as reverse pit and earth drill pit, and river The muddy water discharged from sludge treatment in a pond, sewage treatment, etc. is mixed with groundwater and river water, etc., and becomes a large volume of muddy water, but if it is poured into a river or sewer as it is, the flow becomes slow. It accumulates in places and causes clogging in river flows and sewers. However, since such muddy water is mixed with groundwater and river water to form a large volume of muddy water, it is necessary to transport only solids after removing the water. Need. Therefore, the muddy water discharged at the construction sites, etc. should be removed by removing the water content in the muddy water and discarding only the solid content with a reduced water content to a normal landfill site or industrial waste treatment site. It was placed in the tank to separate the water layer with reduced mud concentration, and only mud with reduced water content was placed in a tank and transported to a remote location by a truck or the like.

However, in recent years, the disposal site is limited, and there is no special method for reducing the amount of disposal or a safe processing method, so that development of such a method is eagerly desired. Therefore, a method of blending an acrylic flocculant and polyaluminum chloride (PAC) into the discharged mud and concentrating the mud by separating the aqueous layer part by standing precipitation (see Comparative Example 3 and Comparative Example 4). ) Or, the sodium silicate is mixed with the discharged mud, and the sodium silicate is gelled by adding sulfuric acid to this, and the solid matter of the mud is adsorbed and separated into the produced gel-like substance. By squeezing the gel-like substance that adsorbed the water, the water content of the solid content in the muddy water was reduced, and the solid matter with the reduced water content was transported to a remote place by a truck or the like for disposal.

On the other hand, in the well excavation work in the oil field, the hot spring, etc., the natural gum aqueous solution and the boric acid compound aqueous solution are injected into the soil to increase the viscosity of the soil, and the natural gum aqueous solution is made into a rubber-like material to obtain soil quality. It is known to improve the overall viscosity and excavate.

[0005]

However, a method of concentrating muddy water by mixing an acrylic flocculant and polyaluminum chloride (PAC) in the muddy water and allowing the mixture to stand and precipitate to separate the water layer portion is As demonstrated in Examples 3 and 4, the muddy water can be dehydrated to some extent, but the size of the agglomerated particles is small, which requires a lot of time for the filtration / separation step, which is a practical problem.

[0006] Further, sodium silicate is mixed with the muddy water, and sulfuric acid is added to the muddy water to gel the sodium silicate, and the solid matter of the muddy water is adsorbed and separated into the produced gel-like material. By squeezing the adsorbed gel, the method of lowering the water content of the solid content of the muddy water is such that when the concentration of the muddy water becomes high, it becomes difficult for large flocs or hard flocs to be generated, and seawater components contained in the muddy water,
Due to the inhibitory effect of metal salts, humic acid substances and organic substances on the formation of flocs, the formed flocs become smaller,
Become softer. Therefore, when the concentration of the muddy water is high, it is necessary to add fresh water to reduce the concentration, and when there is an inhibitor of the flocculant, it is necessary to select and use the flocculant having no influence of the inhibitor. However, the type of muddy water that occurs in construction in the same area also changes, so the work of inspecting the appropriate flocculant and adjusting its concentration each time was extremely complicated.

Further, a method of injecting a natural gum aqueous solution and a boric acid compound aqueous solution into the soil to make the natural gum aqueous solution into a rubber state and improving the viscosity of the whole soil to excavate is the solid content in mud water. There is no intention to reduce the water content, and it is very different in its purpose from the method for treating mud water. Furthermore, the muddy water discharged by cutting is
It is the same as normal muddy water, and even if it is mixed in the soil before cutting, it does not affect the muddy water obtained.

[0008]

[Means for Solving the Problems]

[Summary of the Invention] The inventors of the present invention have conducted intensive studies in view of the above problems, and as a result, a specific combination of compounding agents can agglomerate solids in mud water to form extremely large particles. The present invention has been completed based on the finding that water in mud water can be separated and removed very easily by filtering and separating it. That is, the method for treating muddy water of the present invention is characterized in that a natural gum and a boron compound are added to the muddy water in a method of separating and removing water by aggregating solids in the muddy water.

[Detailed Description of the Invention] [I] Treatment of muddy water (1) Muddy water The muddy water treated in the muddy water treating method of the present invention includes a shield construction method in tunnel construction such as a subway,
For muddy water discharged from oil field and hot spring well drilling, muddy water discharged by pile driving method such as reverse pit and earth drill pit, muddy water discharged from sewage treatment, and sludge treatment of rivers and ponds. Examples include sludge. The effect can be remarkably exhibited by using the muddy water generated by the shield method among these muddy water. These muddy water is mixed with ground water, river water, etc. at the time of cutting and contains a large amount of water and earth and sand, and contains about 5 to 20% by weight of bentonite, cement, CMC, etc. which are difficult to be separated. , The specific gravity is generally 1.1 to 1.
5, preferably 1.2-1.3, particle size generally 20-
2,000 μm, preferably 100 to 1,000 μm,
The solid content of the hydrogen ion concentration (pH) is generally 7 to 13, preferably 7 to 11 is generally contained in the proportion of 10 to 50% by weight, preferably 20 to 30% by weight, and the fluidity is 10
cp to 5,000 cp, preferably 20 to 1,000 c
p. If these muddy water is allowed to flow into a river or a sewer as it is, it accumulates in a place where the flow is slow, and causes clogging in the river flow or the sewer.

(2) Compounding Agent (a) Natural Gum As the natural gum compounded in the method for treating mud water of the present invention, there are plant gums and resinous substances contained in gasoline. It is preferable.

Plant gums The plant gums mentioned above are rubbery substances secreted from the fruits and bark of plants, which are formed from a group of polysaccharides. Although the structure and composition differ depending on the type of plant collected, pure ones are colorless and amorphous and insoluble in ethanol, but when dissolved in water, they become highly viscous liquids and exhibit acidity. The chemical structure of such plant gums is generally unknown, but when hydrolyzed, pentose,
It produces hexose and uronic acid. Examples of the sugar include D-galactose, D-mannose, L-
Arabinose, D-xylose, L-rhamnose and the like, and examples of uronic acid include D-gulonic acid and D-galacturonic acid. Specific examples of such natural gums include guar gum, suntan gum, and local bean gum. Among these, it is preferable to use guar gum.

(B) Boron Compound The boron compound to be added in the method for treating mud water of the present invention is a hydride, oxygen compound, nitrogen compound, halogen compound, sulfide, carbide, acetate or organic boron containing boron. Examples of the compound include boric acid; borate esters such as borate salts such as sodium borate and potassium borate; boron halides; acetate salts such as boryl acetate; boron sulfide; borax. Among these boron compounds, it is preferable to use a water-soluble boron compound, particularly boric acid, sodium borate, potassium borate, or borax.

(C) Other compounding ingredients In the method for treating mud water of the present invention, pulp-based fibers, sodium polyacrylate, etc. are added as optional ingredients in addition to the above-mentioned ingredients within the range not impairing the object of the present invention. You can also

(3) Blending method (a) Addition of natural gum The blending of natural gum in the method for treating muddy water of the present invention is also carried out by adding the finely divided natural gum as it is and thoroughly stirring and mixing. However, a method of mixing a natural gum with water to prepare a natural gum aqueous solution and then mixing this natural gum aqueous solution with the above-mentioned muddy water is a preferable method because it is easy to uniformly mix with the muddy water.

Preparation of Natural Gum Aqueous Solution As a method for preparing the natural gum aqueous solution by mixing the above-mentioned natural gum with water, 50 to 200 parts of water are added to 1 part by weight of natural gum.
It can be prepared by adding a part by weight, preferably 80 to 120 parts by weight, and stirring and mixing under a temperature condition of generally 5 to 50 ° C, preferably 10 to 30 ° C. Glyoxal or the like is preferably added as a dissolution accelerator for the preparation of the natural gum aqueous solution. Further, other compounding agents such as sodium polyacrylate may be added.

Content of Natural Gum The content of the natural gum is generally 0.05 to 0.3 parts by weight, preferably 0.1 to 100 parts by weight of muddy water.
0.3 parts by weight, particularly preferably 0.15 to 0.25 parts by weight. If the blending amount of the natural gum is significantly less than the above range, the strength of the agglomerated block will be insufficient,
On the other hand, if it is excessively excessive, the whole treated mud will gel and lose cohesiveness, which is not preferable.

Muddy Water / Natural Gum Mixture The muddy water / natural gum mixture thus obtained has a viscosity of 2 to 10 poise, is not so viscous, and has a good fluidity. The gum can be easily mixed. However, in this state, the sediment that floats and dissolves in the muddy water seems to be adsorbed on the surface of the natural gum polymer, but the high molecular weight natural gum itself is not yet aggregated. To be
It is in a state of passing through the filter even if it is filtered.

(B) Blending of Boron Compound The blending of the boron compound in the method for treating mud water of the present invention is
It can also be carried out by adding the finely divided boron compound as it is and thoroughly stirring and mixing it, but after preparing the boron compound aqueous solution by mixing the boron compound with water, the boron compound aqueous solution is mixed with the above-mentioned muddy water / natural solution. The method of mixing with the gum mixed solution is a preferable method because it is easy to uniformly mix with the muddy water / natural gum mixed solution. Further, the composition of the above boron compound,
A method of mixing with the above-mentioned muddy water / natural gum mixture is generally used, but the boron compound and the muddy water may be mixed before mixing the natural gum with the muddy water. Almost the same effect can be obtained by either order.

Preparation of Boron Compound Aqueous Solution As a method for preparing the boron compound aqueous solution by mixing the above boron compound with water, 70 to 70 parts of water is added to 1 part by weight of the boron compound.
It can be prepared by adding 200 parts by weight, preferably 100 to 200 parts by weight, and stirring and mixing it under a temperature condition of generally 5 to 50 ° C, preferably 10 to 30 ° C.

Compounding amount of boron compound The compounding amount of the boron compound is generally 0.05 to 0.5 parts by weight, preferably 0.0 to 100 parts by weight of mud water.
It is in the range of 5 to 0.2 parts by weight, particularly preferably 0.1 to 0.2 parts by weight. Further, in Polymer Chemistry Vol. 11, No. 105, pp. 23-27, it is stated that natural gum is crosslinked by adding a small amount of a boron compound to 1 part by weight of natural gum to form a strong rubber-like gel. However, the rubber-like gel cross-linked with such a blending amount is an independent gel, does not break even by the pressure from the outside, and the water taken inside the rubber-like gel cannot be dehydrated. . Therefore, the content of the boron compound in the present invention is 10 to 200 parts by weight, preferably 20 to 150 parts by weight, particularly preferably 50 to 10 parts by weight, relative to 100 parts by weight of the natural gum.
It is preferable that the range is 0 part by weight. Therefore, when the content of the boron compound in the natural gum is less than the above range, the rubber-like elastic gel produced is hard and has an independent shape, so that the water in the gel cannot be dehydrated and the water content is increased. In addition, if the compounding amount of the boron compound with respect to the natural gum exceeds the above range, the natural gum becomes insoluble and the water in the rubbery elastic gel formed cannot be dehydrated.

Muddy water / natural gum / boron compound mixed solution The muddy water / natural gum / boron compound mixed solution produced by adding and mixing the boron compound to the muddy water / natural gum mixed solution has a boron compound addition amount of Rubber-like elastic gel is formed in the initial stage, but when the boron compound is further added and the mixture is stirred, the rubber-like elastic gel is fragmented, and as a result, the viscosity of the mixed solution gradually decreases, resulting in low stirring. It becomes possible to easily stir even by force, large flocs are generated, and the water inside the gel becomes a granular solid that is easily dehydrated. The produced granular solid has a muddy water floc size of 0.1 to 2 mm which is agglomerated by using an ordinary flocculant.
The size is generally 3 to 10 mm, preferably 5 to 50 mm, which is extremely large, and
Since it is a hard floc, it can be easily separated from the clear water by filtration or the like.

(4) Separation / Removal of Water (Filtration) The granular solid is in a state of adsorbing earth and sand suspended / dissolved in muddy water on the surface of the polymer of natural gum. It is suspended and dissolved in muddy water by separating granular solids and clear water by filtering with a relatively coarse mesh such as a belt press, centrifugal separator, vibrating screen or cloth. Soil and sand can be removed together with natural gum. The conventional filter press has an air permeability of 5 to 50, and the belt press has an air permeability of 5
Although those of 0 to 300 have been used, such fine particles can be used in the method of the present invention.
Since the separation ability decreases with such a particle size, in order to improve the separation ability, a filter cloth having the above mesh or more, preferably a filter press having an air permeability of 100 or more, particularly preferably an air permeability of 200 to 300 is used. To be done.
Further, in the belt press, a filter cloth having an air permeability of 50 or more, particularly preferably about 100 to 200 is used. Most preferably, it is carried out with a sieve of about 200 to 300 mesh.

(5) Transportation / Disposal The above-mentioned granular solid matter from which water has been removed is collected and transported by a dump truck or the like to a landfill site or an industrial waste disposal site for disposal. However, the volume of this granular solid is significantly reduced to 1/2 to 1/10 of the volume of untreated muddy water, so not only is the transportation cost saved, but also landfill and industrial waste treatment sites are reduced. Can be used for a long time. Moreover, since the natural gum in the muddy water buried in the landfill or the industrial waste treatment site is a natural product, it is not decomposed by the microorganisms in the soil and remains.

[II] Muddy Water Treatment Device A muddy water treatment device used in the muddy water treatment method of the present invention will be specifically described below with reference to the accompanying drawings showing an embodiment thereof. FIG. 1 is a plan view of a muddy water treatment apparatus used in the muddy water treatment method of the present invention, and FIG. 2 is a front view thereof.
FIG. 3 is a left side view thereof.

As shown in FIG. 1, a muddy water treatment apparatus 1 used in the muddy water treatment method of the present invention basically has a line mixer 2, a reaction tank 3 equipped with an agitator 3a, a vibrating screen 4 and a control board 5. The muddy water treatment device 1 can treat muddy water 6 discharged from the construction site to continuously separate and remove water, and collect solid matter such as earth and sand having a reduced water content. . First, the muddy water 6 discharged from the construction site is supplied from the muddy water supply port 7, and the muddy water 6 is mixed with the natural gum aqueous solution 9 supplied from the natural gum aqueous solution supply port 8 in the line mixer 2, and further the boron compound is added. Boron compound aqueous solution 11 supplied from aqueous solution supply port 10 is mixed in line mixer 2 to obtain muddy water / natural gum / boron compound mixed solution 12. And this mixed liquid 1
Water 14 supplied by a dilution pump 13 is mixed with 2 to be diluted, and the diluted mixed solution 12 is supplied to a reaction tank 3 equipped with a stirrer 3a. Reaction tank 3 equipped with this agitator 3a
The mixed solution 12 that is sufficiently stirred and mixed in the reaction tank 3
A rubber-like elastic gel is formed therein and a boron compound is used to divide the gel into a granular solid material 15. Then, the treatment liquid containing the produced solid particles 15 is discharged from the upper portion of the reaction tank 3 and discharged onto the vibrating sieve 4 vibrated by the motor 16. Moisture 17 that does not contain soil or the like that has passed through the mesh in the vibrating screen 4 is temporarily stored in a storage tank 18 arranged below the vibrating screen 4 and then discharged into a river or a sewer. On the other hand, the granular solid matter 15 from which the water has been removed is collected, transported by a dump truck or the like to a landfill site, an industrial waste treatment site, or the like and discarded.

[0026]

【Example】

Example 1 A drilling fluid containing 10% by weight of Gunma 250-mesh bentonite and 0.1% by weight of sodium nitrohumate as a dispersant was used for excavation at a subway construction site, and a specific gravity of 1.23 was discharged. 25 parts by weight of an aqueous solution containing 1.0% by weight of guar gum prepared by dissolving guar gum in water separately to 100 parts by weight of bentonite-containing muddy water (cement content: 5% by weight, slime content: 32% by weight) having a pH of 12.1 All the components were added, and the mixture was sufficiently stirred at room temperature for 1 minute and mixed.
Next, 20 parts by weight of an aqueous solution containing 1.6% by weight of sodium borate prepared separately by dissolving sodium borate in water was added to this stirring liquid, and the mixture was sufficiently stirred at room temperature for 2 minutes to mix them. At this time, after the stirring was started, the mixed liquid became a rubber-like elastic gel and increased in viscosity, but thereafter, the viscosity of the gel became weak and large flocs were generated. Then, this product solution was placed on a commercially available plastic insect repellent net (mesh spacing: 1 mm x 1 mm), which was then squeezed by hand to filter to obtain a solid content having a water content of 48.7% by weight. Obtained. At this time, the flock was a large flock having a diameter of 4 to 7 mm so that it would not come out from the gap of the plastic insect net having a mesh spacing of 1 mm × 1 mm, and could be easily separated from water. The results obtained are shown in Table 1.

Example 2 A drilling fluid containing 10% by weight of 250 mesh bentonite produced in Gunma and 0.1% by weight of CMC as a thickening agent was used to excavate by a shield method at a sewage construction site and discharged. Bentonite-containing muddy water with a specific gravity of 1.16 and a pH of 11.0 (cement content 0.5% by weight, slime content 2
6 parts by weight) was added to 15 parts by weight of an aqueous solution containing 1.0% by weight of guar gum separately prepared by dissolving guar gum in water, and sufficiently stirred and mixed at room temperature for 1 minute. Next, 25 parts by weight of an aqueous solution containing 1.6% by weight of sodium borate prepared by separately dissolving sodium borate in water was added to this stirring liquid, and they were sufficiently stirred and mixed at room temperature for 2 minutes. At this time, after the stirring was started, the mixed liquid became a rubber-like elastic gel and increased in viscosity, but thereafter, the viscosity of the gel became weak and large flocs were generated. Then, this product solution was placed on a generally commercially available plastic insect-proof net (mesh spacing: 1 mm × 1 mm), which was then squeezed by hand and filtered to obtain a solid content having a water content of 53% by weight. .
At this time, the flock was a large flock having a diameter of 4 to 8 mm which was so small that it did not come out from the gap of the plastic insect net having a mesh spacing of 1 mm × 1 mm, and could be easily separated from water. The results obtained are shown in Table 1.

Example 3 Specific gravity 1.43, pH 9.5, taken from the bottom of a park pond
15 parts by weight of an aqueous solution containing 1.0% by weight of guar gum prepared separately by dissolving guar gum in water is added to 100 parts by weight of sludge containing the silt clay-based organic matter, and the mixture is sufficiently stirred at room temperature for 1 minute. And mixed. Next, 20 parts by weight of an aqueous solution containing 1.6% by weight of sodium borate prepared separately by dissolving sodium borate in water was added to this stirring liquid, and the mixture was sufficiently stirred at room temperature for 2 minutes to mix them. At this time, after the stirring was started, the mixed liquid became a rubber-like elastic gel and increased in viscosity, but thereafter, the viscosity of the gel became weak and large flocs were generated. Then, a plastic insect net which is generally commercially available (mesh spacing: 1 mm x 1
mm) and then filtered by squeezing by hand to obtain a solid content having a water content of 58% by weight. At this time, the flock was a hard flock having a mesh size of 1 mm × 1 mm so as not to come out of the gap of the plastic insect net, and had a diameter of 3 to 6 mm, and could be easily separated from water. The results obtained are shown in Table 1.

Example 4 Excavated at a subway construction site by using a drilling liquid containing 10% by weight of Gunma 250-mesh bentonite and 0.1% by weight of sodium nitrohumate as a dispersant, and discharged with a specific gravity of 1 .23, pH 12.1 bentonite-containing mud water (cement content 5% by weight, slime content 32% by weight) to 100 parts by weight, sodium borate 1.6% by weight prepared separately by dissolving sodium borate in water 7.5 parts by weight of the contained aqueous solution was added, and the mixture was sufficiently stirred at room temperature for 2 minutes and mixed. Next, 30 parts by weight of an aqueous solution containing 1.0% by weight of guar gum, which was separately prepared by dissolving guar gum in water, was added to this stirring liquid, and the mixture was sufficiently stirred at room temperature for 2 minutes. At this time, after the stirring was started, the mixed liquid became a rubber-like elastic gel and increased in viscosity, but thereafter, the viscosity of the gel became weak and large flocs were generated. Then, this product solution was placed on a commercially available plastic insect repellent net (mesh spacing: 1 mm x 1 mm), which was then squeezed by hand to filter to obtain a solid content having a water content of 59.0% by weight. Obtained.
At this time, the flock was a large flock having a diameter of 5 to 15 mm so that it would not come out from the gap of the plastic insect net having a mesh spacing of 1 mm × 1 mm, and could be easily separated from water. The results obtained are shown in Table 1.

Comparative Examples 1 to 2 Muddy water was treated in the same manner as in Example 1 except that the addition amounts of guar gum and sodium borate were changed. The results obtained are shown in Table 1.

Comparative Examples 3 to 4 Muddy water was treated in the same manner as in Example 1 except that sodium polyacrylate was used instead of guar gum and PAC (polyaluminum chloride) was used instead of sodium borate. . The results obtained are shown in Table 1.

[0032]

[Table 1]

[0033]

The method for treating mud water of the present invention as described above is
Large and hard flocs can be formed by a simple operation such as adding two types of chemicals to mud water of various properties, so a large amount of mud can be treated at a narrow place such as a construction site, and mud before treatment can be processed. The volume can be remarkably reduced to 1/2 to 1/10 compared to the volume of, and not only the transportation cost can be saved, but also the landfill site and the industrial waste treatment site can be used for a long time. .

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a muddy water treatment device used in the muddy water treatment method of the present invention.

FIG. 2 is a front view of the muddy water treatment device of FIG.

FIG. 3 is a left side view of the muddy water treatment device of FIG. 1.

[Explanation of symbols]

 1 Muddy Water Treatment Device 2 Line Mixer 3 Reaction Tank 3a Stirrer 4 Vibrating Sieve 5 Control Panel 6 Muddy Water 7 Muddy Water Supply Port 8 Natural Gum Aqueous Solution Supply Port 9 Natural Gum Aqueous Solution 10 Boron Compound Aqueous Solution Supply Supply 11 Boron Compound Aqueous Solution 12 Muddy Water / Natural Gum ・Boron compound mixed solution 13 Dilution pump 14 Water 15 Granular solid matter 16 Motor 17 Moisture that does not contain sand 18 Storage tank

Claims (3)

[Claims] 1. A method for treating mud water, which comprises adding a natural gum and a boron compound to the mud water in a method for separating and removing water by aggregating solids in the mud water. 2. The amount of natural gum added to the muddy water is
The method for treating muddy water according to claim 1, wherein the amount is 0.05 to 0.3 part by weight with respect to 100 parts by weight of muddy water. 3. The method for treating mud water according to claim 1, wherein the amount of the boron compound added to the mud water is 10 to 100 parts by weight based on 100 parts by weight of the natural gum.