JP2006305518A - Method and apparatus for dewatering sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for dewatering sludge capable of stably forming a dewatered cake having a low water content and generating a small amount of odor from hardly dewatered sludge. <P>SOLUTION: In a mixed sludge formation tank 10, a mixed sludge is formed by mixing the hardly dewatered sludge with a ground product of a bamboo grass leaf and/or a bamboo leaf, in a flocculated floc formation tank 20, a flocculated floc is formed by adding a polymer flocculant to the obtained mixed sludge, and in a screw press dewaterer 30, the obtained flocculated floc is mechanically dewatered. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for dewatering sludge generated from sewage treatment facilities, human waste treatment facilities and other wastewater treatment facilities.

  In general, sludge generated from an activated sludge treatment process such as wastewater treatment, human waste treatment, sewage treatment, or the like is sometimes condensed and then agglomerated by addition of a polymer flocculant and dehydrated by mechanical dehydration treatment. In recent years, sludge generated from the activated sludge treatment process due to changes in the quality of sewage such as factory wastewater and household wastewater due to diversification of production items at various manufacturing plants and lifestyles of residents Aggregation is difficult, and the water content of the sludge after dehydration is difficult to decrease.

In particular, the sludge generated when the oxidation ditch treatment method is used for sewage treatment is very poor in dehydration compared with mixed raw sludge, standard activated sludge, digested sludge and the like. This is because the oxidation ditch treatment method is a treatment method in which mechanical agitation and aeration are performed simultaneously, and the aeration time is prolonged compared to other treatment methods. This is considered to be because the fiber content in the sludge that becomes the core of aggregation is decomposed and consumed.
Similarly, most of the sludge generated from the urine treatment facility is removed by the screen provided before the biological treatment, and the generated sludge has less fiber content. It is difficult to reduce.

  On the other hand, composting of sludge is promoted from the viewpoint of recycling waste. In the case of composting treatment, if the water content is too high, it becomes sticky and it becomes difficult to quantitatively supply from the supply device, so it is necessary to reduce the water content of the target sludge as much as possible. In composting, dehydration chemicals and the like must be decomposed by microorganisms.

  Until now, as a means for reducing the moisture content of sludge, there has been proposed a method in which a fibrous material or a plant material such as sawdust or rice husk is mixed with sludge, and then a polymer flocculant is added to dehydrate (JP-A-56). -198200 and JP-A-60-25595). However, in the method of mixing the fibrous material with the sludge, if the quantitative addition of the fibrous material to the sludge or the hydrophilicity of the fibrous material is insufficient, it is difficult to open the fiber in the sludge, and evenly into the sludge. In some cases, mixing cannot be performed, and thus stable processing cannot be performed. Also, some fibrous materials are difficult to be decomposed by microorganisms and may not be suitable for composting. On the other hand, in the method of mixing plant materials such as sawdust and rice husk, the amount added to the sludge solids is generally about 10 to 100%, and the amount of the polymer flocculant added is increased to generate a dewaterable aggregated floc. There is a tendency to increase the sludge treatment cost. Moreover, since it has water repellency depending on the kind of plant, it may be difficult to adjust to sludge.

  In particular, sludge generated from sewage treatment facilities is likely to generate malodorous substances such as hydrogen sulfide and methyl mercaptan, and there is a problem in the vicinity of the dehydration treatment facility and the working environment during storage and transport of the dehydrated cake. For this reason, metal compounds such as iron compounds and zinc compounds or deodorizers such as hypochlorite are added to the sludge during the dehydration process. These deodorizers are used as compost or cement. When used as a raw material, it may be an obstacle, and there is a limitation in use.

  Moreover, as a method of mechanically dewatering hardly dewatering sludge, a screw press dewatering machine has been adopted in a medium-scale sewage treatment plant in recent years. However, because it is intended for difficult-to-dewater sludge, if the refining with the polymer flocculant is insufficient, a strong flocs flocs will not be formed, the water content of the dehydrated cake will not decrease, and the solids recovery rate will also decrease Therefore, stable driving is difficult. As a countermeasure, a method of tempering with an inorganic flocculant and then flocculating with a polymer flocculant is also employed, but in this case, the amount of the polymer flocculant added is increased, the treatment cost increases, and sludge The tempering conditions corresponding to the fluctuations in the properties must be adjusted, and the operation may be complicated.

JP 56-198200 A JP-A-60-25595

  An object of this invention is to provide the sludge dehydration processing method which can solve the above-mentioned problem. In particular, an object of the present invention is to provide a sludge dewatering method that can stably form a dehydrated cake with low moisture content and low odor generation from hardly dewatered sludge.

  As a result of earnest research to solve the above-mentioned problems, the present inventors have used pulverized material of bamboo leaves and / or bamboo leaves to generate low odor and low odor from hardly dewatering sludge. Knowing that a dehydrated cake can be formed stably, the present invention has been made.

  Specifically, according to the present invention, a step of mixing sludge with bamboo leaf and / or bamboo leaf pulverized material to form mixed sludge, and adding a polymer flocculant to the obtained mixed sludge. Thus, there is provided a sludge dewatering method including a step of forming agglomerated floc and a step of mechanically dewatering the obtained agglomerated floc.

  The sludge to be subjected to the dehydration treatment of the present invention is not limited to the type of sludge generated from the activated sludge treatment process in general wastewater treatment, human waste treatment, and sewage treatment, but surplus sludge generated from the oxidation ditch method in particular. Since the sludge generated from the human waste treatment facility has poor cohesiveness and the water content of the dewatered sludge is difficult to decrease, the effect of the present invention can be exhibited most.

  As pulverized products of bamboo leaves and / or bamboo leaves used in the present invention, in addition to leaves such as Miyakozasa, Chimakazasa, Chugokusa, Kamurozasa, Kumazasa, Okamesa, etc. Mention may be made of pulverized leaves such as mushrooms and mushrooms. The most preferable of these is a ground product of Kumazasa leaves. Since the fibers contained in these are strong, the strength of the flocs that incorporate them increases compared to the case where only the polymer flocculant is used, and the resistance increases when squeezed in the dehydrator. In addition to being easy to dehydrate, it also has an effect of suppressing the odor of sludge. Such an effect cannot be obtained with other plant-based pulverized products.

The pulverized product may be obtained by pulverizing leaves as they are or by pulverizing them after drying. As the pulverization method, a known pulverization method can be used.
Moreover, the residue etc. which generate | occur | produce at the time of Sasa extract manufacture can also be used. In the case of using such residues, etc., especially on the recent health food boom, the production of Kumazasa extract is thriving, but it solves the waste disposal problem caused by the large amount of extract residue You can also.

  In the present invention, the shape of the pulverized bamboo leaf and / or bamboo leaf added to the sludge is 1 to 30 mm, preferably about 2 to 10 mm in length. Addition to sludge, mixing or dehydration It is preferable from the workability of time.

  In addition, the crushed material of bamboo leaves and / or bamboo leaves can be either dried or hydrated, but the hydrated material as in the case of the extract residue has a moisture content to stabilize the supply to the sludge. Is preferably constant. A preferable moisture content range is 60% or less. If the water content is too high, it becomes sticky and it becomes difficult to supply a fixed amount from the supply device.

  In the method of the present invention, the mixing ratio of the pulverized material of bamboo leaves and / or bamboo leaves to sludge can vary depending on the concentration of each sludge, but is generally 0.1 for the SS content in the sludge. -20% by weight, preferably 1-10% by weight. If it is less than 0.1% by weight, there is no effect of reducing the moisture content, and if it exceeds 20% by weight, the effect of further reducing the moisture content is lost, and the amount of cake generated increases, which is economically undesirable.

  In the present invention, the pulverized product of bamboo leaf and / or bamboo leaf may be impregnated in advance with a defoaming agent or deodorant generally used for sludge treatment. Further, other natural fiber pulverized products may also be used in combination.

  In the present invention, a polymer flocculant is added to a sludge mixture obtained by mixing pulverized material of bamboo leaves and / or bamboo leaves. By the addition of the polymer flocculant, sludge is aggregated around the pulverized material of bamboo leaves and / or bamboo leaves which are the core of aggregation, forming aggregated flocs. Moreover, it becomes resistance at the time of a fiber part being squeezed within a dehydrator, and becomes easy to dehydrate.

  Preferred examples of the polymer flocculant used in the present invention include anionic polymer flocculants, nonionic polymer flocculants, and cationic polymer flocculants, and in particular, cationic polymer flocculants and amphoteric polymers. Flocculants are preferred.

  As the cationic polymer flocculant, a cationic polymer flocculant having a cationic monomer as an essential component and comprising a copolymer of a cationic monomer or a copolymer of a cationic monomer and a nonionic monomer, and a molecule A cationic polymer flocculant having an amidine unit therein can be preferably used. Preferred examples of the cationic monomer include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, neutralized salts, quaternary salts thereof, and combinations thereof. Preferred examples of the nonionic monomer include acrylamide, methacrylamide, methacrylonitrile, vinyl acetate, and combinations thereof. Examples of the cationic polymer flocculant composed of a copolymer of a cationic monomer and a nonionic monomer that can be used in the present invention include dimethylaminoethyl acrylate and / or methyl chloride quaternized product of dimethylaminoethyl methacrylate / An acrylamide copolymer can be preferably mentioned. Moreover, as a cationic high molecular flocculant which has an amidine unit in the molecule | numerator which can be used in this invention, the amidine thing of an N-vinylformamide / acrylonitrile copolymer can be mentioned preferably, for example.

  As the amphoteric polymer flocculant, a copolymer of a cationic monomer unit, an anionic monomer unit and a nonionic monomer unit can be preferably used. Preferred examples of the amphoteric polymer flocculant that can be used in the present invention include dimethylaminoethyl acrylate and / or dimethylaminoethyl methacrylate methyl chloride quaternized / acrylamide / acrylic acid copolymer.

  Preferable examples of the anionic polymer flocculant include a polyacrylamide partial hydrolyzate, a copolymer of an anionic monomer, and a copolymer of an anionic monomer and a nonionic monomer. As an anionic monomer, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-allylamide ethane sulfonic acid, 2-acrylamide- 2-methylpropanesulfonic acid, 2-methacrylamideamidoethanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, 2-acryloyloxyethanesulfonic acid, 3-acryloyloxypropanesulfonic acid, 4-acryloyloxybutanesulfonic acid 2-methacryloyloxyethanesulfonic acid, 3-methacryloyloxypropanesulfonic acid, 4-methacryloyloxybutanesulfonic acid, and metal salts or ammonium salts of these alkali metals and alkaline earth metals are preferred. It can be mentioned. Preferable examples of the copolymer of the anionic monomer and the nonionic monomer include acrylamide / acrylic acid copolymer and acrylamide / 2-acrylamido-2-methylpropanesulfonic acid copolymer.

  As the nonionic polymer flocculant, a polymer or copolymer of a nonionic monomer can be preferably used. For example, acrylamide, methacrylamide, methacrylonitrile, vinyl acetate and the like, and combinations thereof can be used, and more preferably. Can be polyacrylamide.

In the step of adding the polymer flocculant of the present invention, a two-agent method in which the above-mentioned anionic polymer flocculant is further added after the aforementioned cationic polymer flocculant can be added.
Furthermore, in this invention, before adding a polymer flocculent, an inorganic flocculant and / or an organic polymer coagulant can also be added to the mixed sludge. As the inorganic flocculant, a sulfuric acid band, polyaluminum chloride (PAC), polyferric sulfate (polyiron), ferric chloride and a mixture thereof can be preferably used. Organic polymer coagulants include condensed polyamines, dicyandiamide / formalin condensates, polyethyleneimine, polyvinylimidazoline, polyvinylpyridine, diallylamine salts / sulfur dioxide copolymers, polydimethyldiallylammonium salts, polydimethyldiallylammonium salts / dioxides Sulfur copolymers, polydimethyldiallylammonium salt / acrylamide copolymers, polydimethylasialylammonium salt / diallylamine hydrochloride derivative copolymers, acrylamine salt copolymers and the like can be preferably used. Preferred examples of the condensed polyamine include a condensate of alkylene dichloride and alkylene polyamine, a condensate of aniline and formalin, a condensate of alkylene diamine and epichlorohydrin, a condensate of ammonia and epichlorohydrin, and the like. Preferred examples of the alkylene diamine that condenses with epichlorohydrin include dimethylamine, diethylamine, methylpropylamine, methylbutylamine, and dibutylamine.

  In the method of the present invention, in order to add the pulverized material of bamboo leaves and / or bamboo leaves to the sludge, if there is a sludge storage tank, add it to the sludge storage tank, and if there is no sludge storage tank, concentrate It can be added at any point in the piping from the sludge containing workpiece to the dehydrator.

  In the method of the present invention, in order to mechanically dehydrate the flocs formed by adding a polymer flocculant to sludge mixed with the pulverized material of bamboo leaves and / or bamboo leaves, the usual pressure dehydration is used. A machine, a vacuum dehydrator, a belt press dehydrator, a centrifugal dehydrator, or a screw press dehydrator can be used.

  Further, according to the present invention, a mixed sludge forming tank that forms sludge by mixing bamboo leaf and / or bamboo leaf pulverized material with sludge, and a polymer flocculant is added to the obtained mixed sludge. There is provided a sludge dewatering apparatus including a coagulation floc forming tank that forms coagulation floc and a dehydrator that mechanically dehydrates the obtained coagulation floc.

  FIG. 1 is a schematic explanatory diagram of an embodiment of a sludge dewatering treatment apparatus for carrying out the sludge dewatering treatment method of the present invention. The apparatus shown in FIG. 1 includes a mixed sludge forming tank 10, an agglomerated floc forming tank 20, and a dehydrator 30. The mixed sludge formation tank 10 is equipped with a mechanical agitation device 11 and sufficiently mixes the sludge and the pulverized material of bamboo leaves and / or bamboo leaves. The mixed sludge forming tank 10 and the aggregated floc forming tank 20 are connected by a line 13 for supplying a mixture of the sludge formed in the mixed sludge forming tank 10 and the pulverized material of bamboo leaves and / or bamboo leaves. Yes. A line 27 for supplying the polymer flocculant prepared in the polymer flocculant dissolution tank 25 is also connected to the flocculant floc forming tank 20. The aggregation floc forming tank 20 and the dehydrator 30 are connected by a line 28 that supplies the aggregation floc to the dehydrator. The dehydrator 30 is provided with a dehydrated cake take-out port 31 and a separation liquid discharge line 32.

  In the mixed sludge formation tank 10, sludge obtained from a sewage treatment plant and the like and pulverized material of bamboo leaves and / or bamboo leaves are supplied and mixed by a mechanical stirring device 11 to be mixed with bamboo leaves and / or bamboo. To form a mixture with crushed leaves. This mixture is sent to the aggregation floc forming tank 20 via the line 13. The polymer flocculant prepared in the polymer flocculant dissolution tank 25 is supplied to the aggregation floc forming tank 20 via a line 27. The mixture and the polymer flocculant are mixed together in a flocculant floc forming bath 20 to form a flocculent floc. The agglomerated floc is sent to the dehydrator 30 via the line 28, subjected to mechanical dehydration, and divided into a dehydrated cake and a separated liquid.

  In the apparatus shown in FIG. 1, the inorganic flocculant and / or organic polymer coagulant is added to the sludge after mixing the pulverized material of bamboo leaves and / or bamboo leaves and before adding the polymer flocculant. It further includes an auxiliary agent supply device 40 for adding the above. The auxiliary agent supply device 40 may be configured to supply the auxiliary agent to the mixed sludge forming tank 10 via a line 41 connected to the mixed sludge forming tank 10, or may be connected via a line 42 connected to the line 13. The auxiliary agent may be supplied to the mixed sludge formed in this way.

  According to the present invention, after mixing the pulverized material of bamboo leaves and / or bamboo leaves with sludge, the polymer flocculant is added, and mechanical dehydration treatment is performed, whereby the leaves of bamboo leaves and / or bamboo leaves are pulverized. Since the substance acts as a core of aggregation and sludge can be quickly aggregated by the action of the polymer flocculant and can be used for the subsequent mechanical dehydration treatment, Dehydration can be sufficiently performed.

  Moreover, the deodorizing effect is favorable by using the ground material of a bamboo leaf and / or bamboo leaf, without using the deodorizer by a conventional method. Moreover, since the pulverized product of bamboo leaves and / or bamboo leaves is decomposed by microorganisms, it can be subjected to a composting treatment.

  Furthermore, even when a screw press dehydrator is used, stable operation is possible without adding a large amount of a polymer flocculant or preparing tempering conditions.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.
The composition of the polymer flocculant used in this example is shown in Table 1 below. At the time of use, it prepared so that it might become a 0.2 weight% aqueous solution with distilled water.

なお、得られた脱水ケーキの臭気測定は、以下の方法に従って行った。
（1） 脱水ケーキ２０gを臭気測定用袋（容量：７００ml）に入れ、ゴム栓で密栓する。
（2） 脱水ケーキ入りの臭気測定用袋内に、ゴム栓にシリンジを刺して６００mlの無臭空気を注入する。
（3） シリンジを外した脱水ケーキ入りの臭気測定用袋を３０℃の恒温槽に保管し、消臭剤添加後から所定時間毎（１２時間）に北川式検知管で硫化水素、メチルメルカプタンを測定する。

In addition, the odor measurement of the obtained dehydrated cake was performed according to the following method.
(1) Put 20 g of dehydrated cake in an odor measurement bag (capacity: 700 ml) and seal with a rubber stopper.
(2) Inject a 600ml odorless air into the bag for odor measurement with dehydrated cake by inserting a syringe into a rubber stopper.
(3) Store the odor measurement bag with dehydrated cake with the syringe removed in a 30 ° C thermostatic bath, and add hydrogen sulfide and methyl mercaptan at the Kitagawa-type detector tube every predetermined time (12 hours) after adding the deodorant. taking measurement.

[Example 1]
Add 2wt% of dried mulberry leaves (size is approximately 5-10mm) to SS in sludge to surplus sludge slurry with properties shown in Table 2 generated from oxidation ditch sewage treatment plant. A sludge slurry was prepared.

次に、汚泥スラリー２００mlを３００mlのビーカーに入れ、高分子凝集剤ａをＳＳ当たり１．０％となるように添加し、準備した空の３００ｍｌビーカーに移し替えた。この移し替えを１０回繰り返して、汚泥混合物を凝集させて凝集フロックを形成させた。得られた凝集フロックの大きさをメジャーで測定した後、ビーカー中に形成された凝集フロックを６０メッシュのナイロンろ布で３０秒間重力により脱水して濾過水をメスシリンダーに受け取り、３０秒後の濾過水量を測定した。重力濾過後の汚泥を２枚のろ布に挟み、ピストン型脱水機を用いて、２kg/cm²の圧力で１分間圧搾し、得られた脱水汚泥の質量を測定した後、乾燥機内で１０５℃の温度にて４時間以上乾燥させて乾燥後の質量を測定し、両者の差から含水率を求めた。また、得られた脱水ケーキについて臭気測定試験を行った。結果を表３に記載する。

Next, 200 ml of sludge slurry was put into a 300 ml beaker, and the polymer flocculant a was added to 1.0% per SS, and transferred to the prepared empty 300 ml beaker. This transfer was repeated 10 times to agglomerate the sludge mixture to form agglomerated floc. After measuring the size of the obtained floc floc with a measure, the floc floc formed in the beaker was dehydrated by gravity with a 60 mesh nylon filter cloth for 30 seconds, and filtered water was received in a graduated cylinder. The amount of filtered water was measured. The sludge after gravity filtration is sandwiched between two filter cloths and squeezed for 1 minute at a pressure of ² kg / cm ² using a piston-type dehydrator. After measuring the mass of the dehydrated sludge obtained, It dried for 4 hours or more at the temperature of 0 degreeC, measured the mass after drying, and calculated | required the moisture content from the difference of both. Moreover, the odor measurement test was done about the obtained dewatering cake. The results are listed in Table 3.

[Examples 2-3, Comparative Examples 1-2]
Examples 2 to 3 were tested in the same manner as in Example 1 except that the amount of pulverized dried product of Moso bamboo leaves was changed as described in Table 3. Comparative Example 1 is a control experiment in which the pulverized product of Moso bamboo leaves was not added, and Comparative Example 2 was the addition of Moso bamboo leaves to add cherry wood chips (approximately 5 to 15 mm in size). Control experiment. The results are also shown in Table 3.

［実施例４］
し尿処理施設から発生する表４に示す性状の余剰汚泥と凝集沈澱汚泥の混合汚泥スラリーに、クマザサの葉の乾燥物の粉砕物（大きさは概ね５〜２０mm、含水率５％）をＳＳに対して１wt％添加して汚泥スラリーを調製した。次に高分子凝集剤bを使用して実施例１と同様に脱水試験を行った。結果を表５に記載する。

[Example 4]
In the mixed sludge slurry of surplus sludge and coagulated sediment sludge having the characteristics shown in Table 4 generated from the human waste treatment facility, the dried product of Kumazasa leaves (size is approximately 5 to 20 mm, water content 5%) is changed to SS. On the other hand, sludge slurry was prepared by adding 1 wt%. Next, a dehydration test was conducted in the same manner as in Example 1 using the polymer flocculent b. The results are listed in Table 5.

［実施例５〜６、比較例３〜４］
実施例５〜６は、クマザサの葉の乾燥物の粉砕物及び凝集剤の添加量を表５に記載したように変更した以外は実施例１と同様に試験を行った。比較例３は、クマザサの葉の乾燥物の粉砕物を添加しなかった場合の対照実験であり、比較例４は、クマザサの葉に替えて、籾殻の粉砕物（大きさは概ね３〜１０mm）を使用した場合の対照実験である。結果を表５に併記する。

[Examples 5-6, Comparative Examples 3-4]
Examples 5 to 6 were tested in the same manner as in Example 1 except that the amount of added crushed material and flocculant of the dried leaves of Kumazasa was changed as described in Table 5. Comparative Example 3 is a control experiment in the case where the pulverized product of dried kumazasa leaves was not added, and Comparative Example 4 was a crushed material of rice husks (size was approximately 3 to 10 mm) instead of kumazasa leaves. ) Is a control experiment. The results are also shown in Table 5.

［実施例７］
オキシデーションディッチ方式下水処理場から発生した表６に示す性状の余剰汚泥スラリーに、クマザサ抽出物製造工程で排出される残渣の粉砕物（大きさは概ね１０〜２０mm、含水率９％）をＳＳに対して３wt％添加して汚泥スラリーを調製した。

[Example 7]
The surplus sludge slurry with the properties shown in Table 6 generated from the oxidation ditch sewage treatment plant is crushed by residue (size is approximately 10-20mm, moisture content 9%) discharged in the Kumazasa extract manufacturing process. A sludge slurry was prepared by adding 3 wt% to the slurry.

次に、高分子凝集剤ａを添加して実施例1と同様にして凝集させた後、スクリュープレス脱水機（スクリーン径300mmΦ）に供給し、脱水を行い、実施例１と同様にケーキ脱水率、SS回収率及び臭気測定を行った。結果を表７に記載する。

Next, after adding the polymer flocculant a and aggregating in the same manner as in Example 1, it was supplied to a screw press dehydrator (screen diameter 300 mmΦ) and dehydrated. SS recovery rate and odor measurement were performed. The results are listed in Table 7.

[Examples 8 to 12, Comparative Examples 5 to 6]
Examples 8 to 12 were tested in the same manner as in Example 7 except that the amount of crushed extract of Kumazasa extract residue was changed as described in Table 7. Comparative Examples 5 and 6 are control experiments in the case where the Kumazasa extract residue was not added. The results are also shown in Table 7.

上記実施例の結果から明らかなように、本発明の汚泥脱水処理方法により処理した場合には良好な凝集フロックを形成するので重力ろ過水量は収量が多く、脱水後の汚泥含水率が低下しており、脱水ケーキからの臭気の発生も少ないことがわかる。一方、本発明の構成以外の場合では凝集フロックの状態は不良で、汚泥含水率も高く、脱水ケーキからの臭気の発生が多い。

As is clear from the results of the above examples, when the sludge dewatering treatment method of the present invention is used, a good coagulated floc is formed, so that the amount of gravity filtered water is large, and the sludge moisture content after dehydration is reduced It can be seen that there is little generation of odor from the dehydrated cake. On the other hand, in the case other than the configuration of the present invention, the state of the aggregated floc is poor, the sludge moisture content is high, and odor is often generated from the dehydrated cake.

FIG. 1 is a schematic explanatory diagram of an apparatus for carrying out the sludge dewatering method of the present invention.

Explanation of symbols

10: Mixed sludge formation tank 20: Coagulation floc formation tank 30: Dehydrator 40: Auxiliary supply device

Claims (11)

Mixing sludge with bamboo leaf and / or bamboo leaf pulverized material to form mixed sludge;
Adding a polymer flocculant to the resulting mixed sludge to form a floc floc;
Mechanical dehydration of the obtained floc floc,
Sludge dewatering treatment method.   The method according to claim 1, wherein the mechanical dehydration is performed by a screw press.   The method according to claim 1 or 2, wherein the sludge is generated from a sewage treatment plant.   The method according to any one of claims 1 to 3, wherein the sludge is oxidation ditch treated sludge.   The method according to any one of claims 1 to 4, wherein the pulverized product of bamboo leaves and / or bamboo leaves is a dried product having a length of 1 to 30 mm.   The method according to any one of claims 1 to 4, wherein the pulverized product of bamboo leaves and / or bamboo leaves is an extract residue pulverized product having a moisture content of 60% or less.   The method according to any one of claims 1 to 6, wherein the pulverized product of bamboo leaves and / or bamboo leaves is added in an amount of 0.1 to 20% by weight based on SS content in sludge.   The method further includes the step of adding an inorganic flocculant and / or an organic polymer coagulant to the sludge after adding the pulverized material of bamboo leaves and / or bamboo leaves and before adding the polymer flocculant. The method according to any one of claims 1 to 7. A mixed sludge forming tank for mixing sludge with bamboo leaf and / or bamboo leaf pulverized material to form mixed sludge;
An agglomeration floc forming tank for adding a polymer flocculant to the obtained mixed sludge to form an agglomerated floc;
A dehydrator for mechanically dewatering the obtained flocculent flock;
Including sludge dewatering equipment.   Auxiliary supply device for adding an inorganic flocculant and / or an organic polymer coagulant to the sludge after mixing the pulverized product of bamboo leaves and / or bamboo leaves and before adding the polymer flocculant 10. The apparatus of claim 9, further comprising:   The apparatus according to claim 9 or 10, wherein the dehydrator is a screw press dehydrator.

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