JPH09271799A - Treatment of sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reform a sludge into an easily reutilizing or disposable form by increasing the dissolving rate thereby shortening the time necessary for dissolving. SOLUTION: In this method for eliminating the fluidity of the sludge without removing water content by adding kneading an acrylamide-based water soluble high molecular material having the molecular weight of >=10000, (a) the particle sized of the acrylamide based water soluble high molecular material is controlled to >=50wt.% in fraction of <=100 mesh, >=40wt.% in fraction of <=150 mesh and <=10wt.% in fraction of >=60mesh and (b) the water content is measured and 0.2-4kg high molecular compound per 1kl sludge in the case of 20-50% water content, 1-15kg high molecular compound per 1kl sludge in the case of 40-70% water content or 4-20kg high molecular compound per 1kl sludge in the case of 50-80% water content is added respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to excavated soil generated during excavation in oil wells, natural gas wells, geothermal wells, civil engineering works, etc., and soft soil and sludge generated during civil engineering work and dredging work. The present invention relates to a sludge treatment method for converting sludge into a form that can be easily reused or discarded.

[0002]

2. Description of the Related Art Generally, sludge generated during excavation such as oil wells, natural gas wells, geothermal wells or civil engineering works, and dredging works has a water content of about 20 to 90% although it varies depending on the region. ing. Conventionally, as a method for stabilizing these sludges containing a large amount of water, natural water-soluble polymer substances such as guar gum, semi-synthetic water-soluble polymer substances such as carboxymethylated starch, acrylamide / sodium acrylate copolymer Synthetic water-soluble polymer substances such as coalescence are known.

As the natural water-soluble polymer substance and the semi-synthetic water-soluble polymer substance, fine powders are distributed and used.
Since the water absorption capacity is weaker than that of the synthetic system, there is a disadvantage that it is not suitable for treatment of high water content sludge by itself. As a synthetic water-soluble polymer substance, an acrylamide-based water-soluble polymer substance is most widely used. However, the acrylamide water-soluble polymer has a particle size of 0.15 to 0.50.
Most of them are in mm, and even if they are added to sludge, it takes a long time to dissolve them, the kneading time becomes long, and the efficiency is extremely poor. In addition, a homogel-like film is formed on the surface of the particles, and the dissolution may stop in the state of being left as it is.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a treatment method for improving the dissolution rate, shortening the time required for dissolution, and efficiently reforming sludge into a form that can be easily reused or discarded.

[0005]

The present invention has a molecular weight of 100 for excavated soil generated during excavation and sludge such as soft soil and sludge generated during civil engineering work and dredging work.
In the method for treating sludge, in which 10,000 or more acrylamide-based water-soluble polymer substances are added and kneaded to remove the fluidity of the sludge without removing water, (a) the particle size of the acrylamide-based water-soluble polymer substance is Less than 100 mesh is 5
0% by weight or more and 150 mesh or less are 40% by weight or more, and 60 mesh or more are 10% by weight or less,
(B) The water content of the sludge was measured, and the water content was 20 to 50.
%, The polymer substance is 0.2 to 4 kg per kiloliter of the sludge, and the water content is 40 to 70%, the polymer substance is 1 to 15 per kiloliter of the sludge.
A sludge treatment method is characterized by adding 4 to 20 kg of the polymer substance per kiloliter of the sludge when the water content is 50 kg to 50%.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The sludge to which the present invention is applied will be described. Examples of the sludge treated by the present invention include excavated soil generated during excavation, and soft earth and sand and sludge generated during civil engineering work and dredging work. These sludges contain a large amount of water (usually a water content of 20 to 90%), although it depends on the region.

The water content (%) in the present invention means a value obtained by multiplying the ratio of the weight of water to the weight of sludge dry matter (solid content) by 100. The water content was measured according to JIS A-1203 "Soil water content test method".

As a method for stabilizing sludge containing a large amount of water, the use of synthetic water-soluble polymer substances is known. Acrylamide-based synthetic water-soluble polymeric substances,
There are polymers and copolymers of polyacrylic acid type, polymethacrylic acid type, polyamine type, dicyandiamide type and the like. Of these, the present invention relates to an acrylamide water-soluble polymer substance. The acrylamide-based water-soluble polymer substance was selected because it is anionic or nonionic, has a strong adsorptive power to sludge, has a high molecular weight, and easily exhibits high viscosity.

The acrylamide water-soluble polymer used in the present invention is added for the purpose of increasing the viscosity of water by dissolving it in water contained in sludge and eliminating the fluidity of hydrous sludge. The acrylamide-based water-soluble polymer substance means not only pure polyacrylamide but also partially hydrolyzed polyacrylamide, or copolymerized acrylamide and sodium acrylate. The acrylamide-based water-soluble polymer having a molecular weight of 1,000,000 or more is used. When it is less than 1,000,000, the viscosity increase when dissolved in water is low, which is inconvenient. Most of these commonly produced acrylamide water-soluble polymer substances have a particle size of 0.15 to 0.50 mm,
Even if it is added to the sludge as it is, it takes a long time to dissolve it, the kneading time becomes long, and the efficiency is extremely low. In the present invention, the particle size of the acrylamide water-soluble polymer is 1
50 mesh or more for 00 mesh (0.149 mm) or less, 40 wt% or more for 150 mesh (0.105 mm) or less, and 10 for 60 mesh (0.5 mm) or more
By adjusting the content to be less than or equal to wt%, it was possible to shorten the dissolution time of the acrylamide-based water-soluble polymer substance and to perform rapid treatment. Outside this range, it takes a long time to dissolve and the kneading time becomes long, resulting in extremely poor efficiency. Further, a homogel-like film is formed on the surface of the particles, and the dissolution may be stopped in the state of being left, which is inconvenient.

The fine acrylamide water-soluble polymer substance having the above-mentioned particle size used in the present invention is obtained by pulverizing a coarse material having large particles. Moreover, you may select and use the thing corresponding to the said particle size among the nonstandard products which come out of a classification process at the time of manufacturing general distribution goods.

As a crushing method for coarse particles having large particles,
There are freeze-drying method, jet airflow drying method and the like.

In the sludge treatment method according to the present invention, first, the water content of the sludge is measured. When the water content is 20 to 50%, 0.2 to 4 kg of acrylamide-based water-soluble polymer substance per 1 kiloliter of sludge, and when the water content is 40 to 70%, the acrylamide-based water-soluble polymer per 1 kiloliter of sludge. 1 to 15 kg of polymeric substance, water content of 50 to 80%
In this case, 4 to 20 kg of an acrylamide-based water-soluble polymer substance is added per 1 kiloliter of sludge by a conventional method. If it is less than this range, the effect of eliminating the sludge's fluidity cannot be obtained, and if it exceeds this range, a stringing phenomenon occurs and an appropriate stabilized soil cannot be obtained.

In the present invention, the acrylamide water-soluble polymer is added to sludge while stirring and mixing. As the mixing device, any of a paddle type, drum type, impact type, etc. continuous mixer, a paddle type, a pan type, etc. batch type mixer may be used, or a general-purpose construction machine or a backhoe bucket may be used for stirring. Local mixing may be performed using a special construction machine with wings. The mixing time depends on the mixing means and the structure and size of the mixing device. When the fine acrylamide water-soluble polymer substance of the present invention is used, the mixing time can be shortened to about 1/3 to 2/3 as compared with the conventional case.

The acrylamide-based water-soluble polymer substance used in the present invention may be used alone, or may be mixed with a natural water-soluble polymer substance or a semi-synthetic water-soluble polymer substance, or may be used as a bulking aid or thickening aid You may use it, mixing with an agent. The natural water-soluble polymer, guar gum, seed polysaccharides such as locust bin gum, arabinogalactan gum, resin polysaccharides such as arabic gum, alginic acid, seaweed polysaccharides such as agar,
Fruit polysaccharides such as pectin and silium gum, starch,
Examples thereof include rhizome polysaccharides such as konjak, microbial type sansan gum, zancoat, zanflow, curdlan, succinoglucan, and other animal type gelatins, casein, albumin, shrack and the like. Semi-synthetic water-soluble polymeric substances include starch, guar gum, roasted guar gum,
Starch derivatives, guar gum derivatives, roasted guar gum derivatives, and cellulose derivatives obtained by subjecting cellulose or the like to oxidation, methylation, carboxymethylation, hydroxyethylation, phosphorylation, cationization, etc., such as methyl cellulose, Examples of alginic acid derivatives such as carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose and hydroxypropyl cellulose include alginates and propylene glycol alginate. Examples of the thickening aid include calcium carbonate, fly ash, talc and the like, and examples of the thickening aid include bentonite and the like. The addition amount of these is in the range of 0.1 to 9 with respect to 1 part by weight of the acrylamide-based water-soluble polymer substance.

After treating the sludge with the water-soluble acrylamide polymer, cement, calcium hydroxide, calcium oxide or the like may be added for the purpose of expressing strength.

[0016]

EXAMPLES The present invention will be described below with reference to Examples 1-2 and Comparative Examples 1-2.
However, the present invention is not limited to this. The penetration test used in the following examples and comparative examples was carried out using a Vicat needle device (JIS R5201-1981 cement physical test method) used in a cement setting test. (Example 1, Comparative Example 1) Excavation residual soil composed of sandy silt generated from civil engineering work (specific gravity 1.40, water content 52.4)
%) 1 liter was placed in a mortar mixer, and 2 g of two kinds of polyacrylamide polymer substances having different particle sizes were added separately, and the relationship between the stirring time and the penetration was examined and the state was observed and compared. Example 1 is a polyacrylamide polymer material manufactured by SNF of France, AN934M.
PM was used, and in Comparative Example 1, Acoflock A95 manufactured by Mitsui Cyanamid was used. The results are shown in Table 1.

[0017]

[Table 1]

(Example 2 and Comparative Example 2) 1 liter of sludge (specific gravity: 1.26, water content: 65.5%) collected from the bottom of a lake was placed in a mortar mixer, and two kinds of polyacrylamide polymer substances having different particle sizes were used. 3 g was added separately, and the relationship between the stirring time and the penetration was examined, and the state was observed and compared. As the polyacrylamide polymer material, Example 2 uses Aaron 140T manufactured by Toagosei, and Comparative Example 2
Used PR3005D manufactured by SNF, France. Table 2 shows the results.

[0019]

[Table 2]

In Example 1, 100 mesh or less is 7
1.7% by weight, 45% by weight of 150 mesh or less, and 0% by weight of 60 mesh or more are fine acrylamide water-soluble polymer substances. In Comparative Example 1, 100% or less of mesh is 2.1% by weight. , 150 mesh or less was 0.2% by weight, and 60 mesh or more was 93.4% by weight. The former shows that compared with the latter, excavated soil with a high water content can be modified in a shorter time to develop higher strength. In Example 2, 100 mesh or less is 100.0% by weight, and
In Comparative Example 2, a finer acrylamide water-soluble polymer substance having a mesh size of 150 mesh or less and 99.7% by weight was used.
00 mesh or less is 37.5% by weight, 150 mesh or less is 20.6% by weight, and 60 mesh or more is 3% by weight.
A 6.9% by weight medium roughness acrylamide water soluble polymeric material was used. The former shows that compared with the latter, excavated soil with a high water content can be modified in a shorter time to develop higher strength.

[0021]

The mixing time affects the size of the mixing device,
As a result, it will affect the processing capacity of the machine,
The economic merit obtained by using fine acrylamide-based aqueous polymer substances is extremely large.

Claims (1)

[Claims] 1. An acrylamide-based water-soluble polymer substance having a molecular weight of 1 million or more is added to excavated soil generated during excavation and sludge such as soft earth and sand and sludge generated during civil engineering work and dredging work. In the method for treating sludge which is kneaded and loses the fluidity of the sludge without removing water, (a) the particle size of the acrylamide water-soluble polymer is 100 mesh or less and 50% by weight or more and 150 mesh or less. Is 40% by weight or more, and 60 mesh or more is 1
0% by weight or less, (b) the water content of the sludge is measured, and the water content is 20 to 50.
%, The polymer substance is 0.2 to 4 kg per kiloliter of the sludge, and the water content is 40 to 70%, the polymer substance is 1 to 15 per kiloliter of the sludge.
kg, when the water content is 50 to 80%, the sludge treatment method is characterized in that 4 to 20 kg of the polymer substance is added to 1 kg of the sludge.