JP2001137899A - Dehydration method of sludge mainly composed of inorganic particle and refining agent for dehydration thereof - Google Patents
Dehydration method of sludge mainly composed of inorganic particle and refining agent for dehydration thereofInfo
- Publication number
- JP2001137899A JP2001137899A JP32196099A JP32196099A JP2001137899A JP 2001137899 A JP2001137899 A JP 2001137899A JP 32196099 A JP32196099 A JP 32196099A JP 32196099 A JP32196099 A JP 32196099A JP 2001137899 A JP2001137899 A JP 2001137899A
- Authority
- JP
- Japan
- Prior art keywords
- sludge
- dehydration
- iron
- inorganic particles
- iron sulfate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Treatment Of Sludge (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、無機質粒子を主
体とするスラッジの脱水方法並びにその脱水用調質剤に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dewatering sludge mainly composed of inorganic particles and a conditioning agent for the dewatering.
【０００２】[0002]
【従来の技術】従来、上水の浄水処理にて発生する排水
やスラッジ及び土木工事等で発生する排水などの無機質
粒子を主体とするスラッジは、調質薬剤を用いずに重力
自然沈降濃縮をした後フイルタープレスや遠心分離機等
で脱水処理を行うか、または、従来、無機質粒子の凝集
剤として、硫酸アルミ，ポリ塩化アルミなどのアルミ塩
類や硫酸鉄，塩化鉄などの鉄塩類や消石灰を用いてスラ
ッジのろ過脱水性を改善した後、真空脱水機等で機械脱
水する方法が主としてなされている。2. Description of the Related Art Conventionally, sludge mainly composed of inorganic particles such as wastewater generated in water purification treatment of water and sludge and wastewater generated in civil engineering works is subjected to gravity sedimentation without using a conditioning agent. After that, dehydration treatment is performed by a filter press or a centrifuge, or aluminum salts such as aluminum sulfate and polyaluminum chloride, iron salts such as iron sulfate and iron chloride, and slaked lime are conventionally used as a coagulant for inorganic particles. A method of improving the filtration dewatering property of sludge by using it and then mechanically dewatering with a vacuum dehydrator or the like is mainly used.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記従
来のスラッジをそのまま脱水処理する方法は、スラッジ
中に多く混入する微細粒子のためにろ過脱水性が著しく
低いものであり、脱水設備が大きくなり、非常に長時間
の脱水処理の稼動が必要となるなどの問題点がある。ま
た、塩化第二鉄と消石灰を用いる方法では、スラッジの
ろ過脱水性は向上するものの、脱水処理にて発生するケ
ーキ量が増大し、その処理処分に多大なコストと労力を
要するなどの欠点がある。そして、これらの金属塩類を
単独で用いて生成させた凝集はフロックが小さく、スラ
ッジのろ過脱水性の向上割合は小さい。この発明は、こ
れら従来の方法の問題点を鑑み、ろ過脱水効率が高く、
しかも発生ケーキ及び分離水にも二次公害となるような
有害物質が含有されない無害なスラッジの脱水処理方法
とその調質剤を提供することを目的とする。However, the above-mentioned conventional method of dewatering sludge as it is is very low in filtration dewatering property due to fine particles which are largely mixed in the sludge, and the dewatering equipment becomes large. There is a problem that a very long operation of the dehydration process is required. In addition, the method using ferric chloride and slaked lime improves the filtration dewatering property of sludge, but has the drawback that the amount of cake generated in the dewatering treatment increases, and that disposal and disposal requires enormous cost and labor. is there. The flocculation produced by using these metal salts alone has a small floc, and the rate of improvement in the filtration dewaterability of the sludge is small. The present invention, in view of the problems of these conventional methods, high filtration dewatering efficiency,
Moreover, it is an object of the present invention to provide a harmless sludge dewatering method that does not contain a harmful substance that causes secondary pollution in the generated cake and the separated water, and a conditioning agent therefor.
【０００４】[0004]
【課題を解決するための手段】この発明の要旨は、硫酸
鉄と重合ケイ酸を併用し、硫酸鉄中の鉄に対するケイ素
のモル比が１以上１０以下となる比率で処理対象スラッ
ジに添加混合し無機質粒子を凝集させた後、フィルター
プレスなどで機械脱水処理を行なう無機質粒子を主体と
するスラッジの脱水方法とそのスラッジに用いる調質剤
である。The gist of the present invention is that iron sulfate and polymerized silicic acid are used in combination, and the molar ratio of silicon to iron in iron sulfate is 1 to 10 and is added to the sludge to be treated. A method of dewatering sludge mainly composed of inorganic particles, which is subjected to mechanical dehydration by a filter press or the like after agglomerating the inorganic particles, and a conditioning agent used for the sludge.
【０００５】[0005]
【発明の実施の形態】この発明に係る装置は上記のよう
に構成してあり、上水の浄水処理及び土木工事等で発生
する無機質粒子を主体とする排水またはスラッジに、硫
酸鉄を添加混合した後、カ性ソーダーまたは炭酸ソーダ
ーなどのアルカリ剤を用いてｐＨ９〜１１に調整を行い
水酸化鉄を生成させて無機質粒子の凝集作用を起こさせ
る。次に、重合ケイ酸を先に添加している硫酸鉄中の鉄
に対するモル比が１以上１０以下となる範囲で添加し、
充分に混合撹拌してフロックの形成を行った後、フィル
タープレスや遠心分離機などで脱水処理するものであ
る。BEST MODE FOR CARRYING OUT THE INVENTION The apparatus according to the present invention is constructed as described above, and iron sulfate is added to wastewater or sludge mainly composed of inorganic particles generated in water purification treatment and civil engineering work. After that, the pH is adjusted to 9 to 11 using an alkaline agent such as sodium hydroxide or carbonated carbonate to generate iron hydroxide to cause the aggregation of the inorganic particles. Next, the polymerized silicic acid is added in a range where the molar ratio to iron in the iron sulfate added earlier is 1 or more and 10 or less,
After the floc is formed by sufficiently mixing and stirring, dewatering treatment is performed using a filter press, a centrifuge, or the like.
【０００６】[0006]
【実施例】この発明に係る本発明の無機質粒子を主体と
するスラッジの脱水方法及びその調質剤は、硫酸鉄と重
合ケイ酸を併用し、硫酸鉄中の鉄に対するケイ素のモル
比が１以上１０以下となる比率で添加混合し、無機質粒
子の凝集フロックを生成させた後、スラッジの脱水処理
を行う方法である。これらの金属塩類を用いて無機性粒
子の凝集作用を起こさせるためには、金属の水酸化物を
生成させることが必要である。硫酸鉄をスラッジへ添加
するだけでも水酸化鉄を一部生成して凝集作用が生じる
が、アルカリ剤を用いてｐＨを９以上とすることで沈降
濃縮及び脱水性の高い凝集がなされる。アルカリ剤を用
いてｐＨを９以上に調製するのは、水酸化鉄の生成を容
易にするためと、次の添加する重合珪酸の溶解度がｐＨ
９以上で大きくなり、大きなフロック形成がなされるた
めである。これらの現象より、硫酸鉄を添加した後アル
カリ剤を用いてｐＨを９以上となるように調製すること
が必要である。DETAILED DESCRIPTION OF THE INVENTION The sludge dewatering method of the present invention comprising inorganic particles as a main component and a conditioning agent for the same are a combination of iron sulfate and polymerized silicic acid, wherein the molar ratio of silicon to iron in iron sulfate is 1%. This is a method in which sludge is dehydrated after addition and mixing at a ratio of not more than 10 to generate aggregated flocs of inorganic particles. In order to cause the inorganic particles to aggregate using these metal salts, it is necessary to generate a metal hydroxide. The addition of iron sulfate to the sludge alone produces a part of iron hydroxide to cause coagulation, but by setting the pH to 9 or higher using an alkaline agent, sedimentation and aggregation with high dehydration properties are achieved. The reason why the pH is adjusted to 9 or more by using an alkali agent is to facilitate the generation of iron hydroxide and to make the solubility of the polymer silicic acid to be added next to pH.
This is because the size becomes larger at 9 or more, and a large floc is formed. From these phenomena, it is necessary to adjust the pH to 9 or more using an alkali agent after adding iron sulfate.
【０００７】硫酸鉄の添加率としては、スラッジの固形
物当りＦｅＯとして５〜２０％の範囲が適性である。硫
酸鉄の添加率５％以下では、ろ過脱水性の向上が殆どな
く、また２０％以上添加しても向上割合が非常に小さい
ものとなる。なお、用いる金属塩類として、硫酸鉄の代
わりに塩化鉄や硫酸アルミやポリ塩化アルミなども使用
可能であるが、塩化物を用いた場合は遊離塩素による自
然環境への影響やトリハロメタンの生成などの危惧があ
る。[0007] An appropriate addition rate of iron sulfate is in the range of 5 to 20% as FeO per sludge solid. When the addition rate of iron sulfate is 5% or less, there is almost no improvement in the filtration dewatering property, and even when added in an amount of 20% or more, the improvement ratio becomes very small. In addition, as the metal salts used, iron chloride, aluminum sulfate, polyaluminum chloride, etc. can be used instead of iron sulfate.However, when chloride is used, the influence of free chlorine on the natural environment and the generation of trihalomethane are considered. There is concern.
【０００８】そして、金属塩のみでは、生成する凝集フ
ロックは小さくろ過脱水性の向上は小さい。この一次凝
集させたものに重合ケイ酸を添加混合すると、分子量の
大きな重合ケイ酸の作用によって、小さなフロックが架
橋して大きなろ過脱水性の高い凝集フロックとなる。重
合ケイ酸としては、市販の水ガラスをそのまま用いても
よく、また酸を用いて重合度を上げたものを用いても差
し支えない。また、鉄とケイ素のモル比は、固形物濃度
が小さいときはモル比を大きくし、固形物濃度が高い場
合はモル比を小さくする方が良好なろ過脱水処理ができ
る。モル比を高くするほど重合ケイ酸量が多くなり、ス
ラッジ粘性が増大するので、通常ではモル比を３〜７の
範囲とするのが適切である。[0008] When only the metal salt is used, the flocculated floc generated is small and the improvement in the filtration dewatering property is small. When polymerized silicic acid is added to and mixed with the primary agglomerated material, the small floc is crosslinked by the action of the polymerized silicic acid having a large molecular weight to form a large flocculant having high filtration dewaterability. As the polymerized silicic acid, commercially available water glass may be used as it is, or one having an increased degree of polymerization using an acid may be used. The molar ratio between iron and silicon can be improved by increasing the molar ratio when the solid concentration is low and decreasing the molar ratio when the solid concentration is high. As the molar ratio increases, the amount of polymerized silicic acid increases and the viscosity of sludge increases. Therefore, it is usually appropriate to set the molar ratio in the range of 3 to 7.
【０００９】この発明のスラッジの脱水方法と従来の方
法のろ過脱水試験をフイルタープレス用いて実施した結
果は以下の通りであった。先ず、無機質粒子を主体とす
るスラッジとして、実稼動中の浄水場より重力自然沈降
濃縮スラッジを採取し、このスラッジを、スラッジの
圧入圧力０．５Ｍｐ、圧搾圧力１．５Ｍｐ、雑時間
１０分としてろ過速度を算出し、小型フイルタープレス
を用いて脱水操作を行ない、含水率とろ過速度を比較し
た。The results of the sludge dewatering method of the present invention and the filtration dewatering test of the conventional method performed using a filter press are as follows. First, as a sludge mainly composed of inorganic particles, gravity sedimentation concentrated sludge is collected from a water purification plant in operation, and this sludge is subjected to a sludge injection pressure of 0.5 MPa, a pressing pressure of 1.5 MPa, and a miscellaneous time of 10 minutes. The filtration speed was calculated, dewatering operation was performed using a small filter press, and the water content and the filtration speed were compared.
【００１０】この発明の脱水方法のろ過脱水試験に用い
たスラッジ及び薬剤は、試験に用いたスラッジの固形
物濃度４０ｇ／Ｌ、硫酸鉄（試薬１級）、組成ＦｅＳ
Ｏ４・７Ｈ2Ｏ、純度９８％、ＦｅＯとして添加率１
０％（対スラッジ固形物当たり）水ガラス（試薬１級
品）組成ＳｉＯ2／Ｎａ2Ｏ（モル比＝２〜２．３）、純
度５２〜５７％を設定してスラッジの調質操作を行なっ
た。まず、所定量のスラッジに硫酸鉄をＦｅＯとして、
スラッジ固形物当たり１０％となるように秤量し添加混
合し、炭酸ソーダーまたはカ性ソーダーを急速撹拌しな
がら添加して、スラッジのｐＨが９〜１１程度となるよ
うに調整を行った。次に、添加したアルカリ剤を充分に
混合撹拌を行った後、水ガラス５〜１０％添加した希釈
溶液を緩速撹拌を行いながら、Ｆｅに対してＳｉのモル
比が１，または３，または５となるように添加混合し約
１０分間程度の緩速撹拌を行なった凝集スラッジを上記
のフイルタープレスで脱水操作をおこなった。その結果
は表１の通りであった。The sludge and chemicals used in the filtration dewatering test of the dewatering method of the present invention are as follows.
O4 · 7H 2 O, 98% pure, additive ratio 1 as FeO
0% (vs. sludge per solids) water glass (reagent first grade product) composition SiO 2 / Na 2 O (mole ratio = 2 to 2.3), the refining operation of sludge by setting the 52 to 57 percent purity Done. First, iron sulfate is converted to FeO in a predetermined amount of sludge,
The sludge was weighed so as to be 10% per solid, added and mixed, and sodium carbonate or caustic soda was added with rapid stirring to adjust the pH of the sludge to about 9 to 11. Next, after sufficiently mixing and stirring the added alkaline agent, while slowly stirring the diluted solution containing 5 to 10% of water glass, the molar ratio of Si to Fe is 1, or 3, or The coagulated sludge, which was added and mixed so as to obtain a mixture of 5 and then slowly stirred for about 10 minutes, was subjected to a dehydration operation with the above filter press. The results are shown in Table 1.
【００１１】[0011]
【表１】 [Table 1]
【００１２】この発明は、上記の三種類の調質剤の添加
により、脱水操作の圧入時間５分、圧搾時間１１〜１４
分であり、脱水ケーキの含水率６１．７〜６３．２％の
汚泥が得られ、ろ過速度は２．５９〜４．１１ｋｇ／ｍ
2ｈであった。なお、Ｆｅに対してＳｉのモル比が３，
または５の調質剤を用いたスラッジは、モル比１の調質
剤よりもろ過速度が１．４３〜１．５２ｋｇ／ｍ2ｈ速
いことが分かった。According to the present invention, a press-in time of 5 minutes and a press time of 11 to 14 in a dehydration operation are achieved by adding the above three kinds of the heat treatment agents.
Min, and a sludge having a water content of 61.7 to 63.2% of the dewatered cake is obtained, and the filtration rate is 2.59 to 4.11 kg / m.
2 h. Note that the molar ratio of Si to Fe is 3,
Alternatively, it was found that the sludge using the conditioner of 5 had a filtration rate higher than that of the conditioner having a molar ratio of 1.43 to 1.52 kg / m 2 h.
【００１３】実施例に使用した同一のスラッジを用い
て、従来から行われている、無薬注脱水法（スラッジ
に何も添加せず、そのまま脱水機にて脱水処理する方
法）、塩化第二鉄・消石灰法（最初に塩化第二鉄を対
スラッジ固形物当たり１０％添加混合した後、消石灰を
対固形物当たり３０％添加し充分に撹拌を行った後、脱
水機へ圧入して脱水処理を行う方法）、ポリ塩化アル
ミ法（ポリ塩化アルミを対スラッジ固形物当たり１０％
添加混合した後、炭酸ソーダーを用いて、ｐＨを８〜１
０の範囲で調製した後脱水機にて脱水処理する方法）の
三種類の各方法について脱水試験を実施した。その結果
は以下の通りであった。[0013] Using the same sludge used in the examples, a conventional chemical-free dehydration method (a method of dehydrating the sludge without adding anything to the sludge and using a dehydrator as it is), Iron and slaked lime method (First add 10% ferric chloride to sludge solids and mix, then add 30% slaked lime to solids and mix thoroughly, then press into dehydrator to dehydrate. Method), polyaluminum chloride method (polyaluminum chloride is 10% per sludge solids)
After addition and mixing, the pH was adjusted to 8 to 1 using sodium carbonate.
(A method of dehydrating with a dehydrator after preparing in the range of 0), a dehydration test was carried out for each of the three methods. The results were as follows.
【００１４】[0014]
【表２】 [Table 2]
【００１５】この従来の三種類の各方法は、脱水操作の
圧入時間５分、圧搾時間１７〜１９分であり、脱水ケー
キの含水率６４．３〜６６．７％の汚泥が得られ、ろ過
速度は１．７８〜２．１０ｋｇ／ｍ2ｈであった。従っ
て、この発明と従来方法を比較すると、この発明のスラ
ッジの脱水方法は、圧搾操作の圧搾時間で３〜８分短縮
され、脱水ケーキの含水率で１．１〜５．０％低く、ろ
過速度でも０．４９〜２．３３ｋｇ／ｍ2ｈ速いろ過速
度の結果が得られた。In each of the three conventional methods, the press-in time of the dewatering operation is 5 minutes and the pressing time is 17 to 19 minutes, and sludge having a water content of the dewatered cake of 64.3 to 66.7% is obtained. The speed was between 1.78 and 2.10 kg / m 2 h. Therefore, comparing the present invention with the conventional method, the sludge dewatering method of the present invention can reduce the pressing time of the pressing operation by 3 to 8 minutes, lower the water content of the dewatered cake by 1.1 to 5.0%, Even at a speed of 0.49 to 2.33 kg / m 2 h, a result of a high filtration speed was obtained.
【００１６】[0016]
【発明の効果】以上のように、この発明の無機質を主体
とするスラッジの脱水方法は、従来用いられているアル
ミ塩類や鉄塩類に代わり、硫酸鉄と重合ケイ酸を併用し
た脱水用調質剤を用いることにより、ろ過脱水性の良好
な凝集フロックを生成するものであり、従来の方法に比
べて高効率な脱水処理ができ、しかも生成する脱水ケー
キの量も少なく、且つ脱水ケーキ及び分離水も遊離塩素
による自然環境への影響やトリハロメタンの生成などの
危惧がなく、環境に対して安全となるものである。As described above, the method for dewatering sludge mainly composed of an inorganic substance according to the present invention is a dewatering refining method using iron sulfate and polymerized silicic acid in place of the conventionally used aluminum salts and iron salts. By using the agent, a flocculant having good filtration and dewatering properties can be produced, a more efficient dehydration treatment can be performed as compared with the conventional method, and the amount of dehydrated cake produced is small, and the dewatered cake and separation Water is also safe for the environment, with no concern about the effects of free chlorine on the natural environment or the production of trihalomethane.
Claims (3)
の鉄に対するケイ素のモル比が１以上１０以下となる比
率で処理対象スラッジに添加混合し無機質粒子を凝集さ
せた後、フィルタープレスなどで機械脱水処理を行なう
ことを特徴とする無機質粒子を主体とするスラッジの脱
水方法。1. A method in which iron sulfate and polymerized silicic acid are used in combination, and the mixture is added to a sludge to be treated in a ratio such that the molar ratio of silicon to iron in iron sulfate is 1 or more and 10 or less to aggregate inorganic particles. A method for dewatering sludge comprising mainly inorganic particles, wherein mechanical dewatering is performed by a press or the like.
に、スラッジの固形物当りＦｅＯとして５〜２０％の範
囲で硫酸鉄を添加混合した後、アルカリ剤を用いてｐＨ
９〜１１に調整を行い、次に、重合ケイ酸を硫酸鉄中の
鉄に対するモル比が１以上１０以下、好ましくはモル比
が３〜７の範囲でスラッジに添加し、混合撹拌してフロ
ックの形成を行った後、フィルタープレスなどで機械脱
水処理を行なうことを特徴とする請求項１記載の無機質
粒子を主体とするスラッジの脱水方法。2. A mixture of the above-mentioned sludge mainly composed of inorganic particles and iron sulfate in the range of 5 to 20% as FeO based on the solid content of the sludge, and then mixing with an alkaline agent to adjust the pH.
After adjusting to 9 to 11, polymerized silicic acid is added to the sludge in a molar ratio to iron in iron sulfate of 1 or more and 10 or less, preferably in a range of 3 to 7 and mixed with stirring to obtain floc. The method for dewatering sludge mainly composed of inorganic particles according to claim 1, wherein mechanical dehydration treatment is performed by a filter press or the like after the formation of the sludge.
の鉄に対するケイ素のモル比が１以上１０以下であるこ
とを特徴とする請求項１に記載の脱水用調質剤。3. The heat treating agent for dehydration according to claim 1, wherein iron sulfate and polymerized silicic acid are used in combination, and the molar ratio of silicon to iron in the iron sulfate is 1 or more and 10 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32196099A JP3840857B2 (en) | 1999-11-12 | 1999-11-12 | Method for dewatering sludge mainly composed of inorganic particles and refining agent for dewatering |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32196099A JP3840857B2 (en) | 1999-11-12 | 1999-11-12 | Method for dewatering sludge mainly composed of inorganic particles and refining agent for dewatering |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001137899A true JP2001137899A (en) | 2001-05-22 |
| JP3840857B2 JP3840857B2 (en) | 2006-11-01 |
Family
ID=18138359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32196099A Expired - Fee Related JP3840857B2 (en) | 1999-11-12 | 1999-11-12 | Method for dewatering sludge mainly composed of inorganic particles and refining agent for dewatering |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113998863A (en) * | 2021-11-27 | 2022-02-01 | 深圳市深水水务咨询有限公司 | Deep dehydration treatment method for sludge |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113998863A (en) * | 2021-11-27 | 2022-02-01 | 深圳市深水水务咨询有限公司 | Deep dehydration treatment method for sludge |
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