JP4310863B2

JP4310863B2 - Sludge dewatering equipment

Info

Publication number: JP4310863B2
Application number: JP24842999A
Authority: JP
Inventors: 正季村岡; 成人有松; 護皆方
Original assignee: Kurita Water Industries Ltd; Maezawa Industries Inc
Current assignee: Kurita Water Industries Ltd; Maezawa Industries Inc
Priority date: 1999-09-02
Filing date: 1999-09-02
Publication date: 2009-08-12
Anticipated expiration: 2019-09-02
Also published as: JP2001070716A

Description

【０００１】
【発明の属する技術分野】
本発明は汚泥脱水装置に係り、特に多重円板型脱水機により汚泥を脱水する装置において、ＳＳ回収率の向上を図ることにより、低ＳＳ濃度の脱水濾液を得る汚泥脱水装置に関する。
【０００２】
【従来の技術】
従来、下水処理汚泥等の汚泥を脱水処理するための脱水機として、多重円板型脱水機が知られている（例えば、特開平５−２７７３０９号公報）。図２は、脱水機として多重円板型脱水機を用いた従来の汚泥脱水設備を示す系統図であり、被処理汚泥（原泥）を、まず、原泥槽１から原泥ポンプＰ₁により調質槽２に導入し、ポリ鉄（ポリ硫酸第二鉄）等の無機凝集剤を添加して攪拌することにより汚泥粒子の荷電中和を行い、次いでこの調質汚泥を両性高分子凝集剤（両性ポリマー）溶解槽３からの両性ポリマーと共に凝集槽４に導入して攪拌することにより、フロックの粗大化、緻密化を促進し、得られた凝集汚泥を多重円板型脱水機５に送給して脱水処理し、脱水ケーキを取り出すと共に、多重円板型脱水機５の下部の脱水濾液受部６から脱水濾液を取り出す。この脱水濾液は前段の水処理設備に返送されて処理される。
【０００３】
多重円板型脱水機５は、その内部に、出口方向に向って回転するローラが設けられ、入口側の前半部分では重力脱水が行われ、ローラが上下２段に設けられた後半部分では圧搾脱水が行なわれる。
【０００４】
なお、原泥を調質槽２に送給する原泥ポンプＰ₁としては、一般に、可変定量型の一軸ネジ式ポンプが用いられ、流量計ＦＩで流量制御される。
【０００５】
【発明が解決しようとする課題】
このような汚泥の脱水処理においては、得られる脱水ケーキのＳＳ回収率を高くし、また、脱水濾液のＳＳ濃度を低くすることが望まれる。
【０００６】
しかしながら、従来の多重円板型脱水機では、前半の重力脱水部で得られる脱水濾液のＳＳ濃度は低いが、後半の圧搾脱水部で得られる脱水濾液のＳＳ濃度は高い。即ち、圧搾脱水部では、ケーキが円板の隙間に侵入し、その一部が濾液と共に排出されてしまう。この結果、ＳＳ回収率は８５％前後と低いものとなっていた。
【０００７】
本発明は上記従来の問題点を解決し、汚泥脱水装置、特に、多重円板型脱水機により汚泥を脱水する装置において、ＳＳ回収率の向上を図り、低ＳＳ濃度の脱水濾液を得る汚泥脱水装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明の汚泥脱水装置は、原泥槽と、汚泥脱水部と脱水濾液受部とを有する脱水機と、前記原泥槽内の汚泥を前記汚泥脱水部に送給する手段とを備える汚泥脱水装置において、脱水濾液受部は、低ＳＳ濾液受部と高ＳＳ濾液受部との少なくとも２つに分割されており、高ＳＳ濾液受部には、前記原泥槽からの汚泥送給手段と、前記原泥槽への汚泥返送手段とが連絡していることを特徴とする。
【０００９】
本発明の汚泥脱水装置では、高ＳＳ濾液受部に回収された、ＳＳ濃度の高い脱水濾液を原泥で洗い出して原泥槽に返送することができ、これにより、実質的なＳＳ回収率を向上させることができる。
【００１０】
なお、高ＳＳ濾液受部の濾液をそのまま原泥槽に返送してもＳＳ回収率を向上させることはできるが、このような高ＳＳ濃度の濾液をそのまま移送すると、濾液受部の出口部分や移送配管の途中部分でＳＳが堆積し、閉塞等のトラブルを生じることとなり、円滑な移送を行えない。
【００１１】
本発明は特に、脱水機として多重円板型脱水機を用いる汚泥脱水装置に有効であり、多重円板型脱水機の前半の重力脱水部からの低ＳＳ濃度の濾液を低ＳＳ濾液受部に、後半の圧搾脱水部からの高ＳＳ濃度の濾液を高ＳＳ濾液受部にそれぞれ受け、高ＳＳ濾液受部の濾液を原泥で洗い出して原泥槽に返送することにより、原泥を希釈することなく、即ち、濾液の返送により処理効率を大幅に低減することなく、効率的な脱水処理を行える。
【００１２】
【発明の実施の形態】
以下に図面を参照して本発明の実施の形態を詳細に説明する。
【００１３】
図１は本発明の汚泥脱水装置の実施の形態を示す系統図である。図１において、図２に示す部材と同一機能を奏する部材には同一符号を付してある。
【００１４】
この汚泥脱水装置においては、多重円板型脱水機５の下部の脱水濾液受部を、前半部の重力脱水部５Ａからの低ＳＳ濃度の脱水濾液を受ける低ＳＳ濾液受部６Ａと、後半部の圧搾脱水部５Ｂからの高ＳＳ濃度の脱水濾液を受ける高ＳＳ濾液受部６Ｂとに分割し、低ＳＳ濾液受部６Ａの重力脱水濾液のみを脱水濾液として系外へ取り出す。
【００１５】
高ＳＳ濾液受部６Ｂには、原泥槽１内の原泥の供給配管１１と、高ＳＳ濾液受部６Ｂ内の液を原泥槽１に返送する返送配管１２が接続されており、原泥で高ＳＳ濾液受部６Ｂ内の高ＳＳ濃度の圧搾脱水濾液を洗い出して原泥槽１へ返送するように構成されている。この原泥供給配管１１は、原泥槽１内の原泥を調質槽２に送給する配管から分岐して設けられている。
【００１６】
原泥槽１内には、原泥ポンプＰ₃として渦巻き式ポンプが設けられており、調質槽１への原泥の送給量は、流量計ＦＩに連動する流量調整弁Ｖ₁により所定量に制御される。また、高ＳＳ濾液受部６Ｂに送給する原泥量は弁Ｖ₂の開閉により制御される。
【００１７】
図１の汚泥脱水装置のその他の構成は図２に示す汚泥脱水装置と同様である。
【００１８】
この汚泥脱水装置では、原泥槽１から原泥ポンプＰ₃により供給される原泥のうちの一部が配管１１より多重円板型脱水機５の高ＳＳ濾液受部６Ｂに送給され、残部は調質槽２、凝集槽４を経て多重円板型脱水機５に送給され、図２に示す従来の汚泥脱水装置と同様に凝集、脱水処理される。
【００１９】
多重円板型脱水機５における凝集汚泥の脱水で得られた濾液のうち、重力脱水部５Ａで得られるＳＳ濃度の低い脱水濾液は低ＳＳ濾液受部６Ａを経て系外へ排出される。
【００２０】
一方、圧搾脱水部５Ｂで得られるＳＳ濃度の高い脱水濾液は高ＳＳ濾液受部６Ｂに受けられ、配管１１から供給される原泥により洗い出され、原泥と共に原泥槽１に返送される。
【００２１】
本発明の汚泥脱水装置によれば、このように高ＳＳ濃度の脱水濾液を原泥槽に返送して再度脱水処理工程へ循環するようにすることで、ＳＳ回収率の向上及び脱水濾液のＳＳ濃度の低減を図ることができる。
【００２２】
この汚泥脱水装置では、流量調節弁Ｖ₁の働きにより調質槽２に送給する原泥量を可変定量化でき、弁Ｖ₂の開度調整によって、高ＳＳ濾液受部６Ｂへの送給量を好ましい範囲に調整できるために、原泥ポンプとして従来の可変定量型ポンプではなく、構造が簡単で安価な渦巻式ポンプを用いることができ、設備コストの低減を図ることができる。
【００２３】
なお、図１に示す汚泥脱水装置は、本発明の実施の形態の一例であって、本発明はその要旨を超えない限り、何ら図示のものに限定されるものではない。例えば、脱水濾液受部は、２分割する他、高ＳＳ濾液受部、中ＳＳ濾液受部及び低ＳＳ濾液受部というように３分割以上に区画しても良く、この場合において、中ＳＳ濾液受部については、高ＳＳ濾液受部よりも原泥による洗い出し頻度を低くするようにすることもできる。
【００２４】
脱水機として多重円板型脱水機を用いた場合には、図１に示す如く重力脱水部の濾液を受ける低ＳＳ濾液受部と、圧搾脱水部の濾液を受ける高ＳＳ濾液受部とに２分割するのが有利であり、この場合において、高ＳＳ濾液受部で受ける高ＳＳ濃度の脱水濾液の発生量が原泥処理量の１／１０〜１／３０程度であることが好ましい。
【００２５】
また、高ＳＳ濾液受部の濾液の洗い出しのためにこの高ＳＳ濾液受部に送給する原泥の量は、高ＳＳ濃度の濾液を円滑に移送できる程度であれば良く、高ＳＳ濃度の濾液の発生量やそのＳＳ濃度、原泥のＳＳ濃度等によっても異なるが、一般的には、高ＳＳ脱水濾液の発生量に対して５〜２０倍程度とするのが好ましい。
【００２６】
【実施例】
以下に、実施例及び比較例を挙げて本発明をより具体的に説明する。
【００２７】
実施例１
図１に示す本発明の汚泥脱水装置により、オキシデーションディッチ法による下水処理汚泥（濃度：１．０％）を原泥として、供給量：２ｍ³／ｈｒで脱水処理を行った。
【００２８】
凝集剤としてはポリ鉄を１５％／ＴＳ、両性ポリマー（栗田工業株式会社製クリベストＰ−３５６）を１．３％／ＴＳ添加し、調質槽の滞留時間は４．５分、凝集槽の滞留時間は１５分で処理を行った。
【００２９】
また、多重円板型脱水機としては脱水部の幅が０．５ｍのものを用い、多重円板型脱水機の圧搾脱水部の高ＳＳ濾液受部には、洗浄用に原泥を１ｍ³／ｈｒで循環させた。なお、この圧搾脱水部の濾液（原泥による洗浄前）の発生量は約０．１１ｍ³／ｈｒと原泥処理量に対して少なく、また、そのＳＳ濃度は２５０００ｍｇ／Ｌと、原泥ＳＳ濃度よりも高いため、この濾液を原泥槽に返送することで原泥が希釈されることはなく、高い処理効率で脱水処理を行うことができた。
【００３０】
この脱水処理で得られた濾液のＳＳ濃度とＳＳ回収率は表１に示す通りであった。
【００３１】
比較例１
図２に示す従来の汚泥脱水装置により脱水処理を行い、得られた濾液のＳＳ濃度とＳＳ回収率を表１に示した。なお、脱水処理した原泥、その供給量、凝集剤の薬注量及び各槽の滞留時間は実施例１の場合と同一条件とした。
【００３２】
【表１】

【００３３】
表１より、本発明の汚泥脱水装置によれば、ＳＳ回収率の向上、濾液ＳＳ濃度の低減が図れることがわかる。
【００３４】
【発明の効果】
以上詳述した通り、本発明の汚泥脱水装置によれば、汚泥の脱水によりＳＳ濃度を高い回収率で回収すると共に低ＳＳ濃度の脱水濾液を得ることができる。
【図面の簡単な説明】
【図１】本発明の汚泥脱水装置の実施の形態を示す系統図である。
【図２】従来の汚泥脱水設備を示す系統図である。
【符号の説明】
１原泥槽
２調質槽
３両性ポリマー溶解槽
４凝集槽
５多重円板型脱水機
５Ａ重力脱水部
５Ｂ圧搾脱水部
６濾液受部
６Ａ低ＳＳ濾液受部
６Ｂ高ＳＳ濾液受部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sludge dewatering apparatus, and more particularly to a sludge dewatering apparatus that obtains a dehydrated filtrate having a low SS concentration by improving the SS recovery rate in an apparatus for dewatering sludge using a multiple disk dehydrator.
[0002]
[Prior art]
Conventionally, as a dehydrator for dewatering sludge such as sewage treatment sludge, a multi-disk dehydrator is known (for example, JP-A-5-277309). FIG. 2 is a system diagram showing a conventional sludge dewatering equipment using a multi-disc type dewatering machine as a dewatering machine. The treated sludge (raw mud) is first fed from the raw mud tank 1 to the raw mud pump P _1. Introducing into the tempering tank 2, neutralizing the sludge particles by adding and stirring an inorganic flocculant such as polyiron (ferric ferric sulfate) and then mixing the tempered sludge with the amphoteric polymer flocculant (Amphoteric polymer) By introducing into the flocculation tank 4 together with the amphoteric polymer from the dissolution tank 3 and stirring, floc coarsening and densification are promoted, and the obtained flocculated sludge is sent to the multi-disk dehydrator 5. The dehydrated cake is taken out and the dehydrated cake is taken out, and the dehydrated filtrate is taken out from the dehydrated filtrate receiver 6 at the bottom of the multiple disk dehydrator 5. This dehydrated filtrate is returned to the previous water treatment facility for processing.
[0003]
The multiple disk type dehydrator 5 is provided with a roller that rotates in the direction of the outlet. Gravity dehydration is performed in the front half of the inlet side, and the roller is squeezed in the latter half of the two stages. Dehydration is performed.
[0004]
Note that, as the raw mud pump P ₁ for feeding the raw mud to the refining tank 2, a variable fixed type single screw pump is generally used and the flow rate is controlled by the flow meter FI.
[0005]
[Problems to be solved by the invention]
In such sludge dehydration treatment, it is desired to increase the SS recovery rate of the dehydrated cake obtained and to decrease the SS concentration of the dehydrated filtrate.
[0006]
However, in the conventional multiple disk dehydrator, the SS concentration of the dehydrated filtrate obtained in the first half gravity dewatering unit is low, but the SS concentration of the dehydrated filtrate obtained in the second half pressing dewatering unit is high. That is, in the pressing and dewatering unit, the cake enters the gap between the disks, and a part of the cake is discharged together with the filtrate. As a result, the SS recovery rate was as low as about 85%.
[0007]
The present invention solves the above-mentioned conventional problems, and in the sludge dewatering device, in particular, the device for dewatering sludge with a multi-disk dehydrator, the SS recovery rate is improved and the sludge dewatering to obtain a low SS concentration dehydrated filtrate is obtained. An object is to provide an apparatus.
[0008]
[Means for Solving the Problems]
A sludge dewatering apparatus according to the present invention includes a raw mud tank, a dewatering machine having a sludge dewatering part and a dehydrated filtrate receiving part, and a means for feeding the sludge in the raw mud tank to the sludge dewatering part. In the apparatus, the dehydrated filtrate receiving part is divided into at least two of a low SS filtrate receiving part and a high SS filtrate receiving part, and the high SS filtrate receiving part includes sludge feeding means from the raw mud tank. The sludge returning means to the raw mud tank is in communication.
[0009]
In the sludge dewatering device of the present invention, the high SS concentration dehydrated filtrate recovered in the high SS filtrate receiver can be washed out with the raw mud and returned to the raw mud tank, thereby substantially reducing the SS recovery rate. Can be improved.
[0010]
Although the SS recovery rate can be improved even if the filtrate in the high SS filtrate receiving part is returned to the raw mud tank as it is, if such a high SS concentration filtrate is transferred as it is, the outlet part of the filtrate receiving part or SS accumulates in the middle of the transfer pipe, causing troubles such as clogging, and smooth transfer cannot be performed.
[0011]
The present invention is particularly effective for a sludge dewatering apparatus using a multi-disk dehydrator as a dehydrator, and a low SS concentration filtrate from the gravity dehydration part in the first half of the multi-disk dehydrator is used as a low SS filtrate receiver. , The high SS concentration filtrate from the latter press dewatering part is received in the high SS filtrate receiving part respectively, and the raw mud is diluted by washing out the filtrate of the high SS filtrate receiving part with the raw mud and returning it to the raw mud tank. In other words, efficient dehydration can be performed without significantly reducing the processing efficiency by returning the filtrate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a system diagram showing an embodiment of the sludge dewatering apparatus of the present invention. In FIG. 1, members having the same functions as those shown in FIG.
[0014]
In this sludge dewatering device, a lower SS filtrate receiver 6A for receiving a low SS concentration dehydrated filtrate from the gravity dewatering unit 5A of the first half, Is divided into a high SS filtrate receiver 6B that receives the high SS concentration dehydrated filtrate from the pressure dehydrator 5B, and only the gravity dehydrated filtrate of the low SS filtrate receiver 6A is taken out as a dehydrated filtrate.
[0015]
The high SS filtrate receiver 6B is connected to a raw mud supply pipe 11 in the raw mud tank 1 and a return pipe 12 for returning the liquid in the high SS filtrate receiver 6B to the raw mud tank 1. The high SS concentration of the pressed dehydrated filtrate in the high SS filtrate receiver 6B is washed out by mud and returned to the raw mud tank 1. The raw mud supply pipe 11 is provided by branching from a pipe for supplying the raw mud in the raw mud tank 1 to the tempering tank 2.
[0016]
The Haradoroso 1, spiral pump is provided as the original mud pump P _3, feed rate of the raw sludge to refining vessel 1, where the flow control valve V ₁ which is linked to the flow meter FI Controlled to quantitative. Also, feeding Kyusuru original mud weight at a high SS filtrate receiving 6B is controlled by the opening and closing of the valve V _2.
[0017]
The other configuration of the sludge dewatering device of FIG. 1 is the same as that of the sludge dewatering device shown in FIG.
[0018]
In this sludge dewatering device, a part of the raw mud supplied from the raw mud tank 1 by the raw mud pump P _{3 is} fed from the pipe 11 to the high SS filtrate receiver 6B of the multiple disk dehydrator 5; The remaining portion passes through the tempering tank 2 and the coagulation tank 4 and is fed to the multiple disk dehydrator 5, where it is coagulated and dehydrated in the same manner as the conventional sludge dewatering apparatus shown in FIG.
[0019]
Of the filtrate obtained by dewatering the coagulated sludge in the multiple disk dehydrator 5, the dehydrated filtrate having a low SS concentration obtained by the gravity dewatering unit 5A is discharged out of the system through the low SS filtrate receiving unit 6A.
[0020]
On the other hand, the high SS concentration dehydrated filtrate obtained in the press dewatering unit 5B is received by the high SS filtrate receiving unit 6B, washed out by the raw mud supplied from the pipe 11, and returned to the raw mud tank 1 together with the raw mud. .
[0021]
According to the sludge dewatering apparatus of the present invention, the SS recovery rate and SS of the dehydrated filtrate are improved by returning the dehydrated filtrate having a high SS concentration to the raw mud tank and circulating it again to the dewatering process. The concentration can be reduced.
[0022]
In this sludge dewatering device, the amount of raw mud to be sent to the tempering tank 2 can be variably quantified by the function of the flow control valve V ₁ , and the feed to the high SS filtrate receiver 6B can be made by adjusting the opening of the valve V _2. Since the amount can be adjusted within a preferable range, a spiral pump having a simple structure and an inexpensive structure can be used as the raw mud pump instead of the conventional variable fixed pump, and the equipment cost can be reduced.
[0023]
The sludge dewatering device shown in FIG. 1 is an example of an embodiment of the present invention, and the present invention is not limited to the illustrated one as long as the gist thereof is not exceeded. For example, the dehydrated filtrate receiver may be divided into three or more parts such as a high SS filtrate receiver, a medium SS filtrate receiver, and a low SS filtrate receiver in addition to being divided into two. About a receiving part, the washing-out frequency by raw mud can also be made lower than a high SS filtrate receiving part.
[0024]
When a multiple disk type dehydrator is used as the dehydrator, there are two low SS filtrate receivers that receive the filtrate of the gravity dehydrator and two high SS filtrate receivers that receive the filtrate of the press dewaterer as shown in FIG. In this case, it is preferable that the amount of the high SS concentration dehydrated filtrate received by the high SS filtrate receiver is about 1/10 to 1/30 of the raw mud treatment amount.
[0025]
In addition, the amount of raw mud fed to the high SS filtrate receiver for washing out the filtrate of the high SS filtrate receiver only needs to be such that the filtrate with a high SS concentration can be smoothly transferred. Generally, it is preferably about 5 to 20 times the amount of high SS dehydrated filtrate generated, although it varies depending on the amount of filtrate generated, SS concentration thereof, SS concentration of raw mud, and the like.
[0026]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
[0027]
Example 1
The sludge dewatering apparatus of the present invention shown in FIG. 1 was used for dewatering at a feed rate of 2 m ³ / hr using sewage-treated sludge (concentration: 1.0%) by the oxidation ditch method as raw mud.
[0028]
As coagulant, 15% / TS of polyiron and 1.3% / TS of amphoteric polymer (Kurita Kogyo Co., Ltd. cribest P-356) are added, and the residence time of the tempering tank is 4.5 minutes. The treatment time was 15 minutes.
[0029]
In addition, as the multiple disk type dehydrator, a dewatering part having a width of 0.5 m is used, and the high SS filtrate receiving part of the compression dewatering part of the multiple disk type dehydrator is 1 m ³ of raw mud for washing. / Hr. In addition, the amount of filtrate (before washing with raw mud) generated in this pressure dewatering section is about 0.11 m ³ / hr, which is small relative to the amount of raw mud treated, and the SS concentration is 25000 mg / L, raw mud SS. Since it was higher than the concentration, the filtrate was returned to the raw mud tank, so that the raw mud was not diluted and the dehydration process could be performed with high treatment efficiency.
[0030]
The SS concentration and SS recovery rate of the filtrate obtained by this dehydration treatment were as shown in Table 1.
[0031]
Comparative Example 1
Table 1 shows the SS concentration and SS recovery rate of the filtrate obtained by performing dehydration treatment with the conventional sludge dewatering device shown in FIG. The dewatered raw mud, its supply amount, the amount of the flocculant injected, and the residence time of each tank were the same as in Example 1.
[0032]
[Table 1]

[0033]
Table 1 shows that according to the sludge dewatering apparatus of the present invention, it is possible to improve the SS recovery rate and reduce the filtrate SS concentration.
[0034]
【The invention's effect】
As described in detail above, according to the sludge dewatering apparatus of the present invention, it is possible to recover the SS concentration at a high recovery rate by dewatering the sludge and obtain a dehydrated filtrate having a low SS concentration.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of a sludge dewatering device of the present invention.
FIG. 2 is a system diagram showing a conventional sludge dewatering facility.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Raw mud tank 2 Conditioning tank 3 Amphoteric polymer dissolution tank 4 Coagulation tank 5 Multiple disk type dehydrator 5A Gravity dehydration part 5B Press dehydration part 6 Filtrate receiving part 6A Low SS filtrate receiving part 6B High SS filtrate receiving part

Claims

原泥槽と、
汚泥脱水部と脱水濾液受部とを有する脱水機と、
前記原泥槽内の汚泥を前記汚泥脱水部に送給する手段とを備える汚泥脱水装置において、
脱水濾液受部は、低ＳＳ濾液受部と高ＳＳ濾液受部との少なくとも２つに分割されており、
高ＳＳ濾液受部には、前記原泥槽からの汚泥送給手段と、前記原泥槽への汚泥返送手段とが連絡していることを特徴とする汚泥脱水装置。Raw mud tank,
A dehydrator having a sludge dewatering unit and a dehydrated filtrate receiving unit;
In the sludge dewatering device comprising a means for feeding the sludge in the raw mud tank to the sludge dewatering unit,
The dehydrated filtrate receiver is divided into at least two parts, a low SS filtrate receiver and a high SS filtrate receiver,
The sludge dewatering apparatus, wherein the high SS filtrate receiver is in communication with a sludge feeding means from the raw mud tank and a sludge returning means to the raw mud tank.

脱水機は、多重円板型脱水機であることを特徴とする請求項１に記載の汚泥脱水装置。The sludge dewatering device according to claim 1, wherein the dehydrator is a multiple disk dehydrator.