JP2023012095A - Dewatering aid and production method thereof, and method of dewatering sludge - Google Patents

Abstract

To provide: a dewatering aid which has flocculating properties, strength and detachability from a filter bag that are required in processing with a screw press dehydrator, and which can reduce the water content of sludge; a production method thereof; and a method of dewatering sludge using the dewatering aid.SOLUTION: The dewatering aid comprises a granulation product of a mixture containing an enzymatically treated plant component and a polymer flocculant.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a dewatering aid, a method for producing the same, and a method for dewatering sludge using the dewatering aid.

Various studies have been made so far to remove unnecessary substances in waste water.

For example, a technology has been proposed in which oil seed presscake or meal is dispersed in water and treated with a combination of wet grinding, enzymes and heat, and the fractionated phytate-rich fraction is used as a water treatment agent ( For example, see Patent Document 1).

Further, a technique related to a system for adding a flocculating agent to tempered sludge obtained by adding a dehydration aid to sludge and dewatering the flocculated slurry with a solid-liquid separator has been proposed (see, for example, Patent Document 2). This document describes the addition of biomass that has undergone crushing treatment, expansion softening treatment, or the like.

On the other hand, in recent years, in sewage treatment plants, after digesting activated sludge, it is often disposed after being dehydrated. Sludge digestion is a treatment method in which sludge containing a large amount of organic components, such as sewage sludge, is treated with microorganisms under anaerobic conditions with little oxygen to decompose it into methane gas, carbon dioxide, and the like. The sludge produced by digestion of this sludge is called digested sludge.

For example, as a technology related to wastewater containing organic wastes, a sewage treatment facility using a sludge dehydration aid made of fibrous viscose rayon with a water content of 30 to 80% by weight and a polymer flocculant. , a technique for dewatering sludge generated from human waste treatment facilities and the like has been proposed (see, for example, Patent Document 3).

Japanese Patent Publication No. 2005-503816 JP 2013-233519 A JP 2007-283225 A

The digested sludge mentioned above has the problem that it has a very low fiber content and is very difficult to dewater. In addition, it was found that when conventional dehydration agents are used, the sludge flocs are soft, the separability from the filter bag is low, and the moisture content of the dewatered cake is high. In recent years, the number of cases where sludge is dewatered using a screw press dehydrator has increased, but when the sludge flocs are soft, there is also the problem that it is difficult to dewater with a screw press dehydrator, which requires the strength of the sludge flocs.
In addition, the dispersion or solution prepared using a conventional dehydration agent tends to have a low viscosity, and the plant components contained in the dehydration agent have poor dispersibility, which may cause undissolved components to settle. I also found out.

An object of the present invention is to solve the above-mentioned conventional problems and to achieve the following objects. That is, the present invention provides a dehydration aid capable of producing sludge having cohesiveness, strength, and releasability from filter bags and having a low water content, which are required for treatment by a screw press dehydrator, a method for producing the same, and the An object of the present invention is to provide a method for dewatering sludge using a dewatering aid.

As a result of intensive studies, the present inventors have made a dehydration aid consisting of granules of a mixture containing an enzyme-treated plant component that has been subjected to enzyme treatment and a polymer flocculant, and treated with this dehydration aid. By doing so, it was found that sludge with a low moisture content and having cohesiveness, strength, and releasability from the filter bag required for treatment with a screw press dehydrator can be obtained.

Means for solving the above problems are as follows. Namely
<1> A dehydration aid characterized by comprising granules of a mixture containing an enzyme-treated plant component and a polymer flocculant.
<2> The dehydration aid according to <1>, wherein the enzyme-treated plant component is an enzyme-treated product selected from the group consisting of cellulase, tannase, sucrase, and a combination of two or more thereof. be.
<3> The above <1>, wherein the plant component used in the enzyme-treated plant component is selected from the group consisting of hemp, soybean meal, soybean hull, gluten feed, and a combination of two or more thereof. 2>.
<4> The dehydration aid according to any one of <1> to <3>, which is used to increase the strength of sludge.
<5> A method for producing a dehydration aid according to any one of <1> to <4>,
an enzyme-treated plant ingredient preparation step of treating a plant with an enzyme to obtain an enzyme-treated plant ingredient;
A kneading step of mixing the enzyme-treated plant component and a polymer flocculant, adding water and kneading to obtain a kneaded product;
and a granulation step of granulating the kneaded product to obtain a granulated product.
<6> Adding either the dewatering aid according to any one of <1> to <4> and the dewatering aid obtained by the method for producing the dewatering aid according to <5> to the sludge. A method for dewatering sludge, characterized by comprising

According to the present invention, it is possible to solve the above-mentioned problems in the past and achieve the above-mentioned objects. It is possible to provide a dehydration aid capable of producing sludge with a low C, a method for producing the same, and a method for dewatering sludge using the dehydration aid.

(Dehydration aid)
The dehydration aid of the present invention comprises granules of a mixture containing at least an enzyme-treated plant component and a polymer flocculant, and optionally other components.

<Enzyme-treated plant ingredients>
The plant component used for the enzyme-treated plant component is not particularly limited and can be appropriately selected according to the purpose. soybean-derived surplus biomass such as soybean curd refuse, soybean meal, soybean hulls, gluten feed, wheat-derived surplus biomass, and rapeseed-derived surplus biomass. These may be used individually by 1 type, and may use 2 or more types together.
Among the botanical ingredients used in the enzyme-treated botanical ingredients, hemp, soybean meal, soybean hulls, gluten feed, and combinations of two or more thereof are preferred.

The enzyme used for the enzyme-treated plant component is not particularly limited as long as it can enzymatically decompose the plant component, and can be appropriately selected from detergent enzymes, food enzymes, etc. according to the purpose. Examples include cellulase, tannase, sucrase, hemicellulase, xylanase, chitinase, pectinase, mannanase, and glucanase. These may be used individually by 1 type, and may use 2 or more types together.
Among the enzymes used in the enzyme-treated plant components, enzymes selected from the group consisting of cellulase, tannase, sucrase, and combinations of two or more thereof are preferred.

The method for preparing the enzyme-treated plant component is not particularly limited and can be appropriately selected according to the purpose. It can be prepared in the same manner as in the process.

The content of the enzyme-treated plant component in the dehydration aid is not particularly limited, and can be appropriately selected according to the purpose.

<Polymer flocculant>
The polymer flocculant is not particularly limited, and can be appropriately selected from known polymer flocculants according to the purpose. Examples include molecular flocculants and amphoteric polymer flocculants. These may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the polymer flocculant include polymers containing acrylamide (sometimes simply referred to as "polyacrylamide" or "PAM"), polyamines, sodium alginate, sodium polyacrylate, sodium carboxymethylcellulose (CMC). Examples include salt. Among these, polymers containing acrylamide, polyacrylamide, and sodium polyacrylate are preferred.
The polymer flocculant may have an ionic structure. When the ion is a cation, for example, an ammonium salt, a sulfonium salt and the like can be mentioned. When the ion is an anion, it includes, for example, carboxylate.
Among the polymer flocculants, amphoteric polymer flocculants, which are copolymers of cationic monomer units, anionic monomer units and nonionic monomer units, are preferred.

As the polymer flocculant, a commercial product may be used, or one prepared by a known method may be used.
Examples of the commercially available products include, for example, polyacrylamides such as Flopam AN 905, Flopam AN 926, and Flopam AN 956 (all manufactured by SNF Co., Ltd.); , manufactured by MT Aquapolymer Co., Ltd.), and examples of sodium polyacrylate include Acofloc A-190 (manufactured by MT Aquapolymer Co., Ltd.) and PA-331 (manufactured by Kurita Water Industries Ltd.).

The content of the polymer flocculant in the water treatment agent is not particularly limited and can be appropriately selected according to the purpose.

Mass ratio of the enzyme-treated plant component in the dehydration aid to the polymer flocculant (enzyme-treated plant component/polymer flocculant) (“The enzyme-treated plant component in the dehydration aid , Sometimes referred to as "the content ratio with the polymer flocculant") is not particularly limited, and can be appropriately selected according to the type of wastewater to be treated. 99.9 to 99.9/0.1 is preferred, and 1/9 to 9/1 is more preferred.

<Other ingredients>
The other components are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected depending on the intended purpose. be done. These may be used individually by 1 type, and may use 2 or more types together.
The content of the other components in the dehydration aid is not particularly limited and can be appropriately selected depending on the purpose.

The shape of the dehydration aid is granules (also referred to as particles).

The form (diameter, length) of the granules is not particularly limited and can be appropriately selected according to the purpose. It is preferable that the diameter of the object is 3 mm or less and the length is 3 mm or less. Further, in order to make the passage through the supply port smooth and to consider the solubility at the time of dissolution, it is more preferable that the diameter of the granules is 1 mm or less and the length thereof is 1 mm or less.

The method for producing the dehydration aid is not particularly limited, and can be appropriately selected according to the intended purpose.

The dehydration aid of the present invention has good viscosity when dissolved or dispersed, can suppress settling of insoluble components, and has good dispersibility. In addition, by using the dehydration aid of the present invention, it is possible to obtain sludge with excellent cohesiveness, strength, and detachability from the filter bag necessary for screw press dehydrator, and the water content after treatment is also good. It can be sludge.

The dehydration aid of the present invention can be suitably used, for example, as a dehydration aid for sludge, and can be more suitably used to increase the strength of sludge. Accordingly, the present invention also relates to a sludge strength improving agent comprising granules of a mixture containing the enzyme-treated plant component and the polymer flocculant.
In the present invention, improving the strength of the sludge means increasing the strength of the sludge to such an extent that it can be dehydrated with a screw press dehydrator.

In addition, since various surplus biomass can be used for the dehydration aid of the present invention, it is possible to solve the problem of disposal of surplus biomass and reduce sludge treatment costs.

(Method for producing dehydration aid)
The method for producing a dehydration aid of the present invention includes at least an enzyme-treated plant component preparation step, a kneading step, and a granulation step, and if necessary, further a drying step, a crushing step, a classification step, etc. including the steps of

<Enzyme-treated plant component preparation step>
The enzyme-treated plant component preparation step is a step of treating the plant described in the above-described dehydration aid item with the enzyme described in the above-described dehydration aid item to obtain an enzyme-treated plant component.

The method of the enzyme-treated plant component preparation step is not particularly limited and can be appropriately selected according to the purpose. Examples include a method of obtaining an enzyme-treated plant component by performing a reaction and recovering a solid content after the enzymatic reaction.

The content of the plant component in the plant component-containing liquid is not particularly limited and can be appropriately selected depending on the intended purpose. The plant component-containing liquid may be adjusted to a temperature and pH suitable for the enzyme to be used.

The amount of the enzyme to be used is not particularly limited and can be appropriately selected according to the intended purpose. The plant component-containing liquid may be adjusted to a temperature and pH suitable for the enzyme to be used.

The time for the enzymatic reaction is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 1 minute to 24 hours. In the enzymatic reaction, it can be judged that the enzymatic reaction has been sufficiently performed when the plant component in the plant component-containing liquid has a change in appearance that becomes visibly supple. can be set.
The enzymatic reaction can be stopped, for example, by adding an alkaline agent.

The method for collecting the solid content after the enzymatic reaction is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include centrifugation and filtration.
The solid content may be washed with pure water or the like. Alternatively, it may be dried to a moisture content of about 10 to 70% by mass and used as an enzyme-treated plant component.

<Kneading process>
The kneading step is a step of mixing the enzyme-treated plant component with the polymer flocculant described in the section on the dehydration aid, adding water, and kneading to obtain a kneaded product. In the kneading step, other components described in the above-described dehydration aid may be included as necessary.

The kneading method is not particularly limited and can be appropriately selected according to the purpose. For example, a kneaded product may be obtained by kneading a mixture obtained by mixing the enzyme-treated plant component, the polymer flocculant, the water, and, if necessary, the other components at once. Then, after mixing the enzyme-treated plant component, the polymer flocculant, and optionally the other components to obtain a mixture, water was added to the mixture, and then water was added. The mixture may be kneaded to obtain a kneaded product.

The amount of water used in the kneading step is not particularly limited and can be appropriately selected depending on the intended purpose.

The water used in the kneading step is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include water, organic solvents, water-containing organic solvents, and the like.

The organic solvent is not particularly limited and can be appropriately selected depending on the intended purpose. An organic solvent having a dielectric constant of 30 or less is preferable, and an organic solvent having a dielectric constant of 20 or less is more preferable.
The organic solvent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include hexane, cyclohexane, 2-butanol and ethanol.
The said organic solvent may be used individually by 1 type, and may use 2 or more types together.
Among the organic solvents, hexane, 2-butanol and ethanol are preferred.
By using the organic solvent, it is possible to reduce the occurrence of tackiness during kneading that occurs when using a polymer flocculant, and to prepare a kneaded product with excellent workability.

The content of the organic solvent in the water-containing organic solvent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably more than 10% by mass, more preferably 30% by mass or more, and 50% by mass or more. More preferably, 70% by mass or more is particularly preferable.

The kneading may be performed using a device. The apparatus used for the kneading is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include vertical mixers such as planetary mixers. Conditions such as the rotation speed and time of the mixer are not particularly limited and can be appropriately selected according to the purpose.

<Granulation process>
The granulation step is a step of granulating the kneaded material to obtain a granulated material.

The method of granulating the kneaded product is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include an extrusion granulation method, a stirring granulation method, and a sheet granulation method.
Here, extrusion granulation is a method of granulating by extruding a wet mass of the kneaded material through small holes into a cylindrical shape.
Stirring granulation is a method of putting the kneaded material into a container and aggregating particles in the kneaded material while stirring to form granules.
Sheet granulation is a type of dry granulation, and is a method of crushing powder between two rollers to form a raw material into a sheet, and then pulverizing and granulating the raw material.

The granulation can be performed by appropriately selecting known means. The conditions for the granulation are not particularly limited and can be appropriately selected according to the purpose.

<Drying process>
The drying step is a step of drying the granulated material to obtain a dried material.

The drying can be carried out by appropriately selecting known means such as a vibrating fluidized bed dryer and a hot air dryer. Conditions for the drying are not particularly limited and can be appropriately selected according to the purpose.

The amount of water in the dried product is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 15% by mass or less.

By performing the drying step, crushing becomes easier in the crushing step described later, resulting in high productivity.

<Crushing process>
The crushing step is a step of crushing the dried product to obtain a crushed product.

The crushing can be carried out by appropriately selecting a known means such as a crusher. Conditions for the crushing are not particularly limited and can be appropriately selected according to the purpose.

The degree of pulverization is not particularly limited and can be appropriately selected according to the purpose.

<Classification process>
The classifying step is a step of classifying the crushed material.

The classification can be carried out by appropriately selecting known means, for example, sieving using a sieve, vibration classifier, gravity classifier, centrifugal classifier (cyclone classifier), inertial classifier, etc. are mentioned. Conditions for the classification are not particularly limited, and can be appropriately selected according to the particle size of the dehydration aid.

<Other processes>
The other steps are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected according to the purpose.

According to the method for producing the dehydration aid of the present invention, the dehydration aid of the present invention can be easily manufactured.

(Sludge dehydration method)
The sludge dewatering method of the present invention includes adding to sludge either the dewatering aid of the present invention or the dewatering aid obtained by the production method of the present invention.

The sludge is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include sludge generated in the process of purifying wastewater containing organic unnecessary substances or inorganic unnecessary substances.

The sludge containing organic wastes is not particularly limited and can be appropriately selected according to the purpose. sludge, etc.

Examples of the inorganic waste include nickel, fluorine, iron, copper, zinc, chromium, arsenic, cadmium, tin, and lead. These may be contained individually by 1 type, and 2 or more types may be contained.

Sludge, which is an example of the sludge described above, is generated in the process of purifying wastewater containing organic wastes, for example, in the following manner.
Insolubilizing organic wastes in wastewater by adding an inorganic flocculant to form microflocs, which are suspended solids (hereinafter sometimes referred to as "SS"), and the microflocs is coagulated and sedimented into a supernatant and sludge, and the sludge is separated from the sedimentation product.

Sludge generated in the process of purifying wastewater containing inorganic wastes, which is an example of the sludge, is produced, for example, as follows.
Inorganic ions in the inorganic unwanted matter are insolubilized in the wastewater containing the inorganic unwanted matter by adding an inorganic flocculant or the like to form microflocs as suspended matter, and the microflocs are coagulated and sedimented. The supernatant and sludge are separated by sedimentation, and the sludge is separated from the sedimentation product.

An example of the method for dewatering the sludge will be described below.
The dehydration aid is dissolved or dispersed in water to obtain a solution or dispersion of the enzyme-treated plant component and polymer flocculant.
In the sludge, for example, the concentration of enzyme-treated plant components is 0.001 to 30% by mass, and the concentration of the polymer flocculant is 0.001 to 30% by mass, based on the absolute dry weight of suspended solids in the sludge. %, is provided.
The water used for the dissolution or dispersion is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include pure water (distilled water) and water having an electrical conductivity of 30 μS/cm or more. .

The method of adding the dissolution or dispersion liquid to the sludge is not particularly limited and can be appropriately selected according to the purpose. You may Further, when sludge is constantly or intermittently inflowed or withdrawn, the solution or dispersion may be additionally added in consideration of the amount of inflow or withdrawal of sludge.

The method for dewatering the sludge to which the solution or dispersion liquid has been added is not particularly limited, and can be carried out by appropriately selecting known means, such as a pressurized dehydrator, a vacuum dehydrator, and a belt press. It can be carried out using a dehydrator, a centrifugal dehydrator, a screw press dehydrator, or the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, the dehydration aid of the present invention can be applied to sludge that has been difficult to dewater by conventional screw press dehydrators, so it can be suitably used for dehydration by screw press dewaterers.
Dehydrated sludge (also referred to as "dehydrated sludge") is obtained by the dehydration treatment.

The present invention will be described in more detail below with reference to test examples, but the present invention is not limited to these.

(Test example 1)
<Example 1>
598.2 g of water was added to 1.8 g of Nagasaku jute, which is an example of a plant component, to prepare a plant component-containing liquid having a plant component content of 0.3% by mass.
600 mL of the plant component-containing liquid was heated to about 40° C., and an appropriate amount of citric acid solution was added to adjust the pH to 4.5.
Cellulase (trade name “cellulase (fiber-degrading enzyme)”, manufactured by Hirose Shoji Co., Ltd.), which is an example of an enzyme, is added in an amount of 0.2% by volume to 600 mL of the pH-adjusted plant component-containing liquid, Stir for 30 minutes.
A small amount of alkaline agent (sodium carbonate solution) was added to the stirred liquid to bring the pH of the liquid to approximately pH 7, thereby stopping the enzymatic reaction.
The liquid after the enzymatic reaction is centrifuged, the supernatant is discarded, the solid content is recovered, the solid content is washed twice with pure water, and then dried until the water content reaches about 20% by mass. got the ingredients.

<Example 2>
The enzymatic treatment was performed in the same manner as in Example 1 except that the plant component in Example 1 was replaced with gluten feed to obtain an enzyme-treated plant component.

<Example 3>
Enzyme treatment was performed in the same manner as in Example 1, except that the plant component in Example 1 was replaced with soybean hulls to obtain an enzyme-treated plant component.

<Example 4>
Enzyme treatment was performed in the same manner as in Example 1, except that the plant component in Example 1 was replaced with soybean meal to obtain an enzyme-treated plant component.

<Comparative Example 1>
Nagasaku jute (without enzyme treatment) was used as the plant component of Comparative Example 1.

<Comparative Example 2>
Gluten feed (without enzymatic treatment) was used as the plant component of Comparative Example 2.

<Comparative Example 3>
Soybean hulls (without enzyme treatment) were used as the plant component of Comparative Example 3.

<Comparative Example 4>
Soybean meal (without enzyme treatment) was used as the plant component of Comparative Example 4.

<Evaluation>
0.3% by mass of the plant component of any of Examples 1 to 4 and Comparative Examples 1 to 4, and 0.2 of a polymer flocculant (amphoteric polyacrylamide (CAM-353pk, manufactured by SNF Co., Ltd.)) A solution or dispersion of a plant component and a polymer flocculant containing
Further, as Comparative Example 5, a liquid containing 0.2% by mass of a polymer flocculant (amphoteric polyacrylamide (CAM-353pk, manufactured by SNF Co., Ltd.)) containing no plant components was prepared.

-viscosity-
The viscosity of each liquid prepared above was measured with a Brookfield viscometer. The viscosity was measured using a TVC-7 type viscometer (B-type viscometer) manufactured by Toki Sangyo Co., Ltd. at room temperature of 23° C. with a No. 1 rotor.
Assuming that the viscosity of the liquid of Comparative Example 5 was 100%, the reduction rate of the viscosity of each of the solutions or dispersions of Examples 1 to 4 and Comparative Examples 1 to 4 was calculated from the following formula and evaluated according to the following evaluation criteria. Table 1 shows the results.
Viscosity reduction rate (%) = 100 - (A / B x 100)
In the above formula, "A" represents "the viscosity of the solutions or dispersions of Examples 1 to 4 and Comparative Examples 1 to 4", and "B" represents the "viscosity of the liquid of Comparative Example 5".
--Evaluation criteria--
○: Viscosity reduction rate is 20% or less ×: Viscosity reduction rate is more than 20%

As shown in Table 1, it was confirmed that the use of an enzyme-treated plant component reduced the decrease in the viscosity of the solution or dispersion and improved the viscosity.

-Dispersibility-
The concentration of suspended solids in the entire liquid prepared above was measured as follows (concentration of suspended solids in the entire liquid at the time of preparation).
About 10 cc was sampled from a depth of about 2 cm from the liquid surface, and the concentration of suspended solids was measured with a DR3900 absorption photometer (manufactured by HACH).
In addition, the concentration of suspended solids in the supernatant of each liquid after standing still for 1 day was measured as follows (concentration of suspended solids in supernatant after standing for 1 day).
About 10 cc was sampled from a depth of about 2 cm from the liquid surface, and the concentration of suspended solids was measured with a DR3900 absorption photometer (manufactured by HACH).
The amount of change (Y) and rate of change (Z) in the concentration of suspended solids were calculated from the following equations, and the dispersibility was evaluated according to the following evaluation criteria. Table 2 shows the results.
Suspended solid concentration change (mg/L) = W (mg/L) - X (mg/L)
Suspended solid concentration change rate (%) = 100 - (Y / W × 100)
In the above formula, "W" is "suspended solids concentration in the entire liquid at the time of preparation", "X" is "suspended solids concentration in the supernatant after standing for one day", "Y" is "suspended solids concentration represents the amount of change.
--Evaluation criteria--
○: Suspended solid concentration change rate (Z) is 20% or less ×: Suspended solid concentration change rate (Z) is more than 20%

表２中、「Ｗ」は「作製時の液全体における懸濁物質濃度」、「Ｘ」は「１日間静置後の上澄みにおける懸濁物質濃度」、「Ｙ」は「懸濁物質濃度の変化量」、「Ｚ」は「懸濁物質濃度の変化率」を表す。

In Table 2, "W" is "suspended solids concentration in the entire liquid at the time of preparation", "X" is "suspended solids concentration in the supernatant after standing for 1 day", "Y" is "suspended solids concentration "Amount of change" and "Z" represent "rate of change in suspended solid concentration".

As shown in Table 2, in Comparative Examples 1 to 4 in which enzyme treatment was not performed, most of the plant components settled after standing for one day, whereas in Examples 1 to 4 in which enzyme treatment was performed. , the plant components did not settle much even after standing for 1 day. Therefore, it was confirmed that dispersibility can be improved by using enzyme-treated plant components.

(Test example 2)
<Test Example 2-1-1>
30 parts by mass of enzyme-treated Nagasaku jute prepared in the same manner as in Example 1, 20 parts by mass of polymer flocculant (amphoteric polyacrylamide (CAM-353pk, manufactured by SNF Co., Ltd.)), and 50 parts by mass of water The parts by mass were kneaded to obtain a kneaded product.
The kneaded product is subjected to extrusion granulation (rotation speed: 30 rpm, screen diameter φ0.8 mm) using an extrusion granulator (basket type wet granulator, manufactured by Kikusui Seisakusho) to obtain granules (particles). rice field.
The particles were dried (120° C., 30 minutes) using a dryer (conveyor type dryer, manufactured by Godai Engineering Co., Ltd.) to obtain a dried product.
The dried product was pulverized (1,000 rpm, screen diameter φ5 mm) using a pulverizer (Orient Mill, manufactured by Orient Machinery Co., Ltd.) to obtain a pulverized product.
The pulverized material was classified (sieve opening: 850 μm) using a classifier (vibration classifier, manufactured by Dalton) to obtain a dehydration aid.

<Test Example 2-1-2>
Dehydration aid of Test Example 2-1-2 in the same manner as in Test Example 2-1-1 except that the enzyme-treated Nagasaku jute in Test Example 2-1-1 was replaced with enzyme-free Nagasaku jute. got the drug.

<Test Example 2-2-1>
Tested in the same manner as in Test Example 2-1-1, except that the enzyme-treated Nagasaku jute in Test Example 2-1-1 was replaced with an enzyme-treated gluten feed prepared in the same manner as in Example 2. A dehydration aid of Example 2-2-1 was obtained.

<Test Example 2-2-2>
The dehydration aid of Test Example 2-2-2 was added in the same manner as in Test Example 2-2-1, except that the enzyme-treated gluten feed in Test Example 2-2-1 was replaced with a non-enzyme-treated gluten feed. Obtained.

<Test Example 2-3>
Except that the enzyme-treated Nagasaku jute in Test Example 2-1-1 was replaced with cellulose acetate (no enzyme treatment, particle size of 355 μm or less, weight average molecular weight (Mw) of 184,000, manufactured by Kanto Kagaku Co., Ltd.), A dehydration aid of Test Example 2-3 was obtained in the same manner as in Test Example 2-1-1.

<Test Example 2-4>
Test Example 2-4 in the same manner as in Test Example 2-1-1, except that the enzyme-treated Nagasaku jute in Test Example 2-1-1 was replaced with Nagasaku jute prepared by the following expansion and softening treatment. A dehydration aid was obtained.
－Expansion softening treatment－
Changsaku jute without enzyme treatment was held under high pressure (3 MPa) for 1 hour, and then the pressure was released abruptly. The expansion softening process is a process in which the fluid such as moisture contained in the compressed biomass cell membranes expands explosively by rapidly releasing the pressure, and the biomass cell membranes are crushed.

<Evaluation>
－Sludge treatment performance－
Water was added to the dehydration aids obtained in Test Examples 2-1-1 to 2-4 so that the solid content concentration was 0.3% by mass, and the mixture was stirred to obtain solutions or dispersions.
To 200 g of digested sludge slurry (solid content concentration 4%, solid content 0.8 g) generated from a sewage treatment plant, the solution or dispersion was added at 4% by absolute dry weight with respect to suspended solids (SS). After that, transfer between centrifuge tubes was performed 10 times to aggregate.
After centrifuging the flocculated sludge (1,500 G, 5 minutes), the supernatant was removed, the sludge was transferred onto filter paper, and centrifugal dehydration (2,500 G, 10 minutes) was performed to obtain dehydrated sludge.

[Cohesiveness]
The flocculation property was evaluated by the following evaluation method and evaluation criteria when flocculation was carried out by transferring between centrifuge tubes 10 times. Table 3 shows the results.
-Evaluation method-
The evaluation liquid after coagulating by transferring between centrifuge tubes 10 times is passed through a sieve with a 1.5 mm opening mesh, the amount of sludge remaining on the sieve is measured, and the residual sieve sludge rate (%) is calculated by the following formula. bottom.
Residual sieve sludge rate (%) = {(weight of sludge remaining on sieve)/(weight of sludge put into sieve)} x 100
-Evaluation criteria-
◎: Residual sludge rate of 90% or more ○: Residual sludge rate of 60% or more and less than 90% △: Residual sludge rate of 30% or more and less than 60% ×: Residual sludge rate of less than 30%

〔Strength〕
The strength of sludge was evaluated by the following evaluation method and evaluation criteria. Table 3 shows the results.
-Evaluation method-
The sludge remaining on the sieve after the cohesion test described above is sandwiched between two discs with a diameter of 3 cm, and a 30 g weight is placed on the discs and allowed to stand for 10 seconds (hereinafter referred to as "after loading"). ), the sludge protruding from the disk was removed, the amount of sludge remaining on the disk was weighed, and the residual disk sludge rate (%) was calculated by the following formula.
Remaining disk sludge rate (%) = {(weight of sludge remaining on disk after loading)/(weight of sludge placed on disk)} x 100
-Evaluation criteria-
◎: Residual disc sludge rate is 90% or more ○: Residual disc sludge rate is 60% or more and less than 90% △: Residual disc sludge rate is 30% or more and less than 60% ×: Residual disc sludge rate is less than 30% In addition, when the above evaluation criteria are ⊚ or ◯, it can be evaluated that the sludge can be used in a screw press machine.

[Peelability]
The sludge detachability was evaluated according to the following evaluation method and evaluation criteria. Table 3 shows the results.
-Evaluation method-
In the cohesiveness test described above, after sieving, the sieves were turned upside down and the amount of sludge dropped from the sieves was measured, and the peeled sludge ratio (%) was calculated by the following formula.
Peeled sludge rate (%) = {(Weight of sludge dropped from the sieve by turning over the sieve) / (Weight of sludge remaining on the sieve after sieving)} x 100
-Evaluation criteria-
◎: Stripped sludge rate is 90% or more ○: Stripped sludge rate is 60% or more and less than 90% △: Stripped sludge rate is 30% or more and less than 60% ×: Stripped sludge rate is less than 30%

[Water content]
The water content of the dehydrated sludge (hereinafter sometimes referred to as "water content") was obtained as follows.
The weight of the dehydrated sludge was measured to obtain the weight A of the dehydrated sludge. Subsequently, the weight B of the dehydrated sludge dried in an oven at 105° C. to absolute dryness (water content of 0.05% or less) was measured. Here, a heat drying moisture meter (MX-50, manufactured by A&D Co., Ltd.) was used to confirm the moisture content. From these, the water content was obtained by dividing the weight of water contained in the dewatered sludge (AB) by the weight of the dewatered sludge (A) to obtain a percentage. The results are shown in Table 3 below.

As shown in Table 3, when the dehydration aids of Test Examples 2-1-1 and 2-2-1 were used, excellent results were obtained in all of cohesiveness, strength, peelability, and water content. became.

Claims (6)

A dehydration aid comprising granules of a mixture containing an enzyme-treated plant component and a polymer flocculant. 2. The dehydration aid according to claim 1, wherein the enzyme-treated plant component is an enzyme-treated product selected from the group consisting of cellulase, tannase, sucrase, and combinations of two or more thereof. 3. Any one of claims 1 to 2, wherein the plant ingredients used in the enzyme-treated plant ingredients are selected from the group consisting of hemp, soybean meal, soybean hulls, gluten feed, and combinations of two or more thereof. A dehydration aid as described. 4. The dehydration aid according to any one of claims 1 to 3, which is used for increasing the strength of sludge. A method for producing a dehydration aid according to any one of claims 1 to 4,
an enzyme-treated plant ingredient preparation step of treating a plant with an enzyme to obtain an enzyme-treated plant ingredient;
A kneading step of mixing the enzyme-treated plant component and a polymer flocculant, adding water and kneading to obtain a kneaded product;
and a granulation step of granulating the kneaded product to obtain a granulated product. It comprises adding either the dehydration aid according to any one of claims 1 to 4 and the dehydration aid obtained by the method for producing the dehydration aid according to claim 5 to the sludge. Sludge dewatering method.