JP2020138110A - Water treatment device, manufacturing method of water treatment device and water treatment method - Google Patents

Water treatment device, manufacturing method of water treatment device and water treatment method Download PDF

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JP2020138110A
JP2020138110A JP2019033504A JP2019033504A JP2020138110A JP 2020138110 A JP2020138110 A JP 2020138110A JP 2019033504 A JP2019033504 A JP 2019033504A JP 2019033504 A JP2019033504 A JP 2019033504A JP 2020138110 A JP2020138110 A JP 2020138110A
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water
water treatment
membrane
coagulation
treated
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祐人 端谷
Yuto Hataya
祐人 端谷
駿一 荒井
Shunichi Arai
駿一 荒井
元 高橋
Hajime Takahashi
高橋　　元
山本　学
Manabu Yamamoto
学 山本
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Oji Holdings Corp
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Oji Holdings Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

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  • Separation Using Semi-Permeable Membranes (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)
  • Biological Treatment Of Waste Water (AREA)

Abstract

To provide a water treatment device that can reduce a size of the device and reduce an investment amount and an installation area when obtaining membrane filtrate from the water contaminated with organic matter or suspended matter.SOLUTION: There is provided a water treatment device 21 including: a coagulation settling tank 11 for obtaining coagulation-treated water 3 by adding a coagulant to water to be treated 2; and a filtration membrane 13 for obtaining treated water 4 by membrane filtration of the coagulation-treated water 3, in which a water area load of the coagulation settling tank 11 is 12 to 48 m/D, and there are also provided a manufacturing method of the water treatment device and a water treatment method.SELECTED DRAWING: Figure 1

Description

本発明は、水処理装置、水処理装置の製造方法および水処理方法に関する。 The present invention relates to a water treatment device, a method for manufacturing the water treatment device, and a water treatment method.

近年、水資源のリサイクルが重要視されるようになり、放流排水の再処理のために生物処理水などをろ過膜でさらに高度処理して回収することが求められている。 In recent years, the recycling of water resources has become more important, and it is required to further treat biologically treated water and the like with a filtration membrane for reprocessing of discharged wastewater and recover it.

特許文献１には、有機物含有排水を生物処理する第１の生物処理手段と、第１の生物処理手段から流出する生物処理水を固液分離する第１の固液分離手段と、第１の固液分離手段で分離された分離水を生物処理する第２の生物処理手段と、第２の生物処理手段から流出する生物処理水を固液分離する第２の固液分離手段と、第２の固液分離手段で分離された分離水に含まれる溶存物質を除去する高度処理手段とを有する有機物含有排水の処理装置が記載されている。 Patent Document 1 describes a first biological treatment means for biologically treating organic matter-containing wastewater, a first solid-liquid separation means for solid-liquid separation of biologically treated water flowing out of the first biological treatment means, and a first. A second biological treatment means for biologically treating the separated water separated by the solid-liquid separation means, a second solid-liquid separation means for solid-liquid separation of the biologically treated water flowing out from the second biological treatment means, and a second. Described is a treatment apparatus for organic matter-containing wastewater having an advanced treatment means for removing dissolved substances contained in the separated water separated by the solid-liquid separation means of.

特許文献２には、有機性排水を受け入れる、微生物を担持した流動担体を保持する第１の好気性生物処理槽と、第１の好気性生物処理槽の流出水を受け入れる、微生物を担持した流動担体と浮遊活性汚泥とを保持する第２の好気性生物処理槽と、第２の好気性生物処理槽の流出水を受け入れ、流出水を上澄水と沈殿汚泥とに分離する沈殿槽と、沈殿槽の上澄水を受け入れ、上澄水に同伴される汚泥を分離すると共に処理水を排出する分離膜浸漬槽であって、槽内に浸漬された分離膜モジュールと分離膜モジュールの下方に設けられた散気手段とを備える分離膜浸漬槽と、沈殿槽の沈殿汚泥を第２の好気性生物処理槽に返送する第１の汚泥返送手段と、分離膜浸漬槽の汚泥を第２の好気性生物処理槽に返送する第２の汚泥返送手段と、を具備する生物処理装置が記載されている。 Patent Document 2 describes a first aerobic biological treatment tank that accepts organic wastewater and holds a fluid carrier carrying microorganisms, and a flow that receives effluent from the first aerobic biological treatment tank and carries microorganisms. A second aerobic biological treatment tank that holds the carrier and suspended activated sludge, a sedimentation tank that receives the effluent from the second aerobic biological treatment tank and separates the effluent into supernatant water and sedimented sludge, and sedimentation. It is a separation membrane immersion tank that receives the supernatant water of the tank, separates sludge accompanying the supernatant water, and discharges the treated water, and is provided below the separation membrane module and the separation membrane module immersed in the tank. A separation membrane immersion tank provided with an air diffuser, a first sludge return means for returning the sedimented sludge in the sedimentation tank to a second aerobic organism treatment tank, and a second aerobic organism for the sludge in the separation membrane immersion tank. A biological treatment apparatus comprising a second sludge return means for returning to the treatment tank is described.

特開２００７−１６０２３３号公報JP-A-2007-160233 特開２００６−０８２０２４号公報Japanese Unexamined Patent Publication No. 2006-082024

ここで、特許文献１では、担体を備える第１の生物処理手段；無機凝集槽、ｐＨ調整および高分子凝集槽、沈殿槽；担体を備える第２の生物処理手段；無機凝集槽、ｐＨ調整および高分子凝集槽、沈殿槽；膜ろ過の順番（請求項１、２、［００３８］、［００４０］参照）で水処理を行うことが記載されている。しかしながら、本発明者らが特許文献１に記載の水処理装置を用いて水処理を行ったところ、ろ過膜が閉塞しやすい問題があることがわかった。 Here, in Patent Document 1, a first biological treatment means including a carrier; an inorganic coagulation tank, a pH adjusting and polymer coagulation tank, a settling tank; a second biological treatment means including a carrier; an inorganic coagulation tank, pH adjustment and It is described that the water treatment is performed in the order of polymer coagulation tank, settling tank; membrane filtration (see claims 1, 2, [0038] and [0040]). However, when the present inventors performed water treatment using the water treatment apparatus described in Patent Document 1, it was found that there was a problem that the filtration membrane was easily clogged.

本発明が解決しようとする課題は、有機物や懸濁物で汚染された水から膜ろ過水を得る際に、装置を小型化でき、投資額や設置面積を抑制できる水処理装置を提供することである。 An object to be solved by the present invention is to provide a water treatment apparatus capable of reducing the size of the apparatus and reducing the investment amount and the installation area when obtaining membrane-filtered water from water contaminated with organic substances or suspensions. Is.

本発明では、生物膜処理における通常の凝集沈殿槽の設計値（４８ｍ／Ｄを超える）よりも水面積負荷を小さく設計することによって高分子凝集剤を用いずに凝集物の沈降速度を高めて限外ろ過膜の閉塞を抑制でき、かつ、水面積負荷を特定の値以上とすることによって建設費や設置面積を抑制できることを見出し、上記課題を解決した。
なお、特許文献２には、沈殿槽の水面積負荷が５〜３０ｍ／Ｄであることが好ましいと記載されているが、特許文献２は凝集沈殿槽を用いることを否定する文献である。特許文献２に記載の生物処理装置は、有機性排水を２段の流動担体槽で処理した後、「余剰汚泥除去のための凝集剤を必要とすることなく」（［０００６］参照）、汚泥を自然沈降分離し、上澄み液に随伴する汚泥を膜分離活性汚泥で分離するとともに処理水を排出する方法である。 In the present invention, the sedimentation rate of aggregates is increased without using a polymer flocculant by designing the water area load to be smaller than the design value (more than 48 m / D) of a normal coagulation sedimentation tank in biological membrane treatment. We have found that the blockage of the ultrafiltration membrane can be suppressed and the construction cost and the installation area can be suppressed by setting the water area load to a specific value or more, and the above-mentioned problems have been solved.
In addition, Patent Document 2 describes that the water area load of the settling tank is preferably 5 to 30 m / D, but Patent Document 2 is a document denying the use of a coagulation settling tank. The biological treatment apparatus described in Patent Document 2 treats organic wastewater in a two-stage fluidized carrier tank, and then “without the need for a flocculant for removing excess sludge” (see [0006]), sludge. This is a method in which the sludge accompanying the supernatant is separated by membrane separation activated sludge and the treated water is discharged.

上記課題を解決するための具体的な手段である本発明の構成と、本発明の好ましい構成を以下に記載する。
［１］ 被処理水に凝集剤を添加して凝集処理水を得る凝集沈殿槽と、
凝集処理水を膜ろ過して処理水を得るろ過膜を備え、
凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである、水処理装置。
［２］ 凝集剤が無機凝集剤である、請求項１に記載の水処理装置。
［３］ 無機凝集剤がアルミニウム系凝集剤または鉄系凝集剤である、請求項２に記載の水処理装置。
［４］ 凝集剤として高分子凝集剤を含まない、請求項１〜３のいずれか一項に記載の水処理装置。
［５］ ろ過膜が限外ろ過膜である、請求項１〜４のいずれか一項に記載の水処理装置。
［６］ 水処理装置が、凝集沈殿槽を１つのみ備える、請求項１〜５のいずれか一項に記載の水処理装置。
［７］ ろ過膜が生物処理槽の内部以外に配置される、請求項１〜６のいずれか一項に記載の水処理装置。
［８］ 凝集沈殿槽の上流に生物膜処理槽を備える、請求項１〜７のいずれか一項に記載の水処理装置。
［９］ 凝集沈殿槽の水面積負荷が２０〜４５ｍ／Ｄである、請求項１〜８のいずれか一項に記載の水処理装置。
［１０］ 水面積負荷が１２〜４８ｍ／Ｄである沈殿槽を備える既存設備に対して、
沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程と、
凝集沈殿槽の下流にろ過膜を連結する工程とを含む、水処理装置の製造方法。
［１１］ 被処理水に凝集剤を添加して凝集沈殿槽を通過させて凝集処理水を得る凝集沈殿工程と、
凝集処理水をろ過膜で膜ろ過して処理水を得る膜ろ過工程を備え、
凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである、水処理方法。
［１２］ 凝集剤が無機凝集剤であり、かつ、凝集剤として高分子凝集剤を含まない［１１］に記載の水処理方法。 The configuration of the present invention, which is a specific means for solving the above problems, and the preferred configuration of the present invention are described below.
[1] A coagulation settling tank for obtaining coagulation-treated water by adding a coagulant to the water to be treated.
Equipped with a filtration membrane that obtains treated water by membrane filtration of coagulated treated water.
A water treatment device having a water area load of 12 to 48 m / D in the coagulation sedimentation tank.
[2] The water treatment apparatus according to claim 1, wherein the flocculant is an inorganic flocculant.
[3] The water treatment apparatus according to claim 2, wherein the inorganic flocculant is an aluminum-based flocculant or an iron-based flocculant.
[4] The water treatment apparatus according to any one of claims 1 to 3, which does not contain a polymer flocculant as a flocculant.
[5] The water treatment apparatus according to any one of claims 1 to 4, wherein the filtration membrane is an ultrafiltration membrane.
[6] The water treatment device according to any one of claims 1 to 5, wherein the water treatment device includes only one coagulation sedimentation tank.
[7] The water treatment apparatus according to any one of claims 1 to 6, wherein the filtration membrane is arranged outside the inside of the biological treatment tank.
[8] The water treatment apparatus according to any one of claims 1 to 7, further comprising a biofilm treatment tank upstream of the coagulation sedimentation tank.
[9] The water treatment apparatus according to any one of claims 1 to 8, wherein the water area load of the coagulation sedimentation tank is 20 to 45 m / D.
[10] For existing equipment equipped with a settling tank with a water area load of 12 to 48 m / D
A step of providing a coagulant addition means in the settling tank to form a coagulation settling tank, and
A method for manufacturing a water treatment apparatus, which comprises a step of connecting a filtration membrane downstream of a coagulation sedimentation tank.
[11] A coagulation-sedimentation step of adding a coagulant to the water to be treated and passing it through a coagulation-precipitation tank to obtain coagulation-treated water.
It is equipped with a membrane filtration step to obtain treated water by membrane filtration of aggregated treated water with a filtration membrane.
A water treatment method in which the water area load of the coagulation sedimentation tank is 12 to 48 m / D.
[12] The water treatment method according to [11], wherein the flocculant is an inorganic flocculant and does not contain a polymer flocculant as the flocculant.

本発明によれば、有機物や懸濁物で汚染された水から膜ろ過水を得る際に、装置を小型化でき、投資額や設置面積を抑制できる水処理装置を提供できる。 According to the present invention, it is possible to provide a water treatment device capable of reducing the size of the device and reducing the investment amount and the installation area when obtaining membrane-filtered water from water contaminated with organic substances or suspensions.

図１は、本発明の水処理装置を用いた水処理方法の一例のフローチャートである。FIG. 1 is a flowchart of an example of a water treatment method using the water treatment apparatus of the present invention. 図２は、本発明の水処理装置を用いた水処理方法の他の一例のフローチャートである。FIG. 2 is a flowchart of another example of a water treatment method using the water treatment apparatus of the present invention.

以下において、本発明について詳細に説明する。以下に記載する構成要件の説明は、代表的な実施形態や具体例に基づいてなされることがあるが、本発明はそのような実施形態に限定されるものではない。なお、本明細書において「〜」を用いて表される数値範囲は「〜」前後に記載される数値を下限値および上限値として含む範囲を意味する。 Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

［水処理装置］
本発明の水処理装置は、被処理水に凝集剤を添加して凝集処理水を得る凝集沈殿槽と、凝集処理水を膜ろ過して処理水を得るろ過膜を備え、凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである。
本発明によれば、有機物や懸濁物で汚染された水から膜ろ過水を得る際に、装置を小型化でき、投資額や設置面積を抑制できる水処理装置を提供できる。
ここで、生物処理の方法として、活性汚泥法と生物膜法がある。活性汚泥法を用いた活性汚泥処理では通常は凝集剤を用いない沈殿槽を用いて沈殿した汚泥を返送汚泥として再利用することが一般的である。しかし、活性汚泥法では、汚泥の状態が悪化すると汚泥の一部が流出して活性汚泥処理水に混じり、ろ過膜の閉塞などのろ過障害が頻繁に起きていた。
一方、微生物を担体に保持する生物膜法では、原理的に汚泥管理が不要であり、さらに凝集剤を添加する凝集沈殿槽を用いることが一般的であるため、汚泥が流出する問題を防止できる。しかし、生物膜法における通常の凝集沈殿槽の設計では、土地面積が限られる問題や設備コストの問題から設置面積を可能な限り小さくする必要があるため、一般的に水面積負荷を６０〜７０ｍ／Ｄ程度とせざるを得なかった。この場合、無機凝集剤と高分子凝集剤を併用して凝集物の沈降速度を高めなければ適正な処理が期待できなかった。そして、この場合に凝集沈殿槽とろ過膜を併用して凝集処理水をさらに高度処理して回収しようとすると、凝集処理水に残存する高分子凝集剤により、ろ過膜の閉塞などのろ過障害が起こる問題があった。
これに対し、本発明では、凝集沈殿槽とろ過膜を併用する場合に従来と比較して大型の凝集沈殿槽を用いることで凝集物の沈降速度を顕著に高め、ろ過膜の閉塞を抑制して安定運転でき、かつ、設置面積が大き過ぎないようにした。凝集沈殿槽の土地面積が限られる問題や設備コストの問題に反して、凝集沈殿槽の水面積負荷を本発明で規定する程度にすることは、ろ過膜の閉塞を抑制して安定運転できる（顕著にフラックスが大きくできる）という顕著な効果があるとの知見を見出してはじめて到達できた構成である。そもそも凝集沈殿槽を大型化する実験を試みることが困難である中、本発明の水処理装置の構成に到達することは当業者にとって容易ではなかった。
なお、本発明は、凝集沈殿槽に流入する被処理水が、生物膜法を用いて前処理された態様に限られない。また、本発明は、高分子凝集剤を用いない態様に限られない。
以下、本発明の水処理装置の好ましい態様について説明する。 [Water treatment equipment]
The water treatment apparatus of the present invention includes a coagulation-sedimentation tank for obtaining coagulation-treated water by adding a coagulant to the water to be treated, and a filtration membrane for membrane-filtering the coagulation-treated water to obtain treated water. The area load is 12 to 48 m / D.
According to the present invention, it is possible to provide a water treatment device capable of reducing the size of the device and reducing the investment amount and the installation area when obtaining membrane-filtered water from water contaminated with organic substances or suspensions.
Here, as a method of biological treatment, there are an activated sludge method and a biological membrane method. In the activated sludge treatment using the activated sludge method, it is common to reuse the sludge that has settled in a settling tank that does not normally use a coagulant as return sludge. However, in the activated sludge method, when the sludge condition deteriorates, a part of the sludge flows out and mixes with the activated sludge treated water, and filtration problems such as clogging of the filtration membrane frequently occur.
On the other hand, in the biomembrane method in which microorganisms are retained on a carrier, sludge management is not required in principle, and a coagulation sedimentation tank to which a coagulant is added is generally used, so that the problem of sludge outflow can be prevented. .. However, in the design of a normal coagulation sedimentation tank in the biomembrane method, it is necessary to make the installation area as small as possible due to the problem of limited land area and the problem of equipment cost, so the water area load is generally 60 to 70 m. I had to set it to about / D. In this case, proper treatment could not be expected unless the settling rate of the agglomerates was increased by using an inorganic flocculant and a polymer flocculant in combination. Then, in this case, if the coagulation sedimentation tank and the filtration membrane are used in combination to further treat and recover the coagulation-treated water, the polymer flocculant remaining in the coagulation-treated water causes filtration problems such as clogging of the filtration membrane. There was a problem that occurred.
On the other hand, in the present invention, when the coagulation sedimentation tank and the filtration membrane are used in combination, the sedimentation rate of the agglomerates is remarkably increased by using a large coagulation sedimentation tank as compared with the conventional case, and the clogging of the filtration membrane is suppressed. Stable operation was possible, and the installation area was not too large. Contrary to the problem that the land area of the coagulation sedimentation tank is limited and the problem of equipment cost, setting the water area load of the coagulation sedimentation tank to the extent specified in the present invention suppresses the clogging of the filtration membrane and enables stable operation ( It is a configuration that can be reached only after finding the finding that it has a remarkable effect (the flux can be increased remarkably). In the first place, it was difficult for those skilled in the art to reach the configuration of the water treatment apparatus of the present invention while it was difficult to attempt an experiment to increase the size of the coagulation sedimentation tank.
The present invention is not limited to the mode in which the water to be treated flowing into the coagulation sedimentation tank is pretreated by using the biomembrane method. Further, the present invention is not limited to the mode in which the polymer flocculant is not used.
Hereinafter, preferred embodiments of the water treatment apparatus of the present invention will be described.

＜水処理装置の全体的な構成＞
本発明の水処理装置の全体的な構成の好ましい態様を、図面を用いて説明する。図１は、本発明の水処理装置を用いた水処理方法の一例のフローチャートである。
図１に示した水処理装置２１は、被処理水２（原水１）に凝集剤を添加して凝集処理水３を得る凝集沈殿槽１１と、凝集処理水３を膜ろ過して処理水４を得るろ過膜１３を備える。
図１に示した水処理装置２１では、凝集剤添加手段１２は凝集沈殿槽１１内の被処理水２に凝集剤を添加できるように配置される。 <Overall configuration of water treatment equipment>
A preferred embodiment of the overall configuration of the water treatment apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart of an example of a water treatment method using the water treatment apparatus of the present invention.
The water treatment apparatus 21 shown in FIG. 1 includes a coagulation sedimentation tank 11 for obtaining coagulation-treated water 3 by adding a coagulant to the water to be treated 2 (raw water 1), and the coagulation-treated water 3 is membrane-filtered to treat water 4. The filtration membrane 13 is provided.
In the water treatment device 21 shown in FIG. 1, the coagulant adding means 12 is arranged so that the coagulant can be added to the water to be treated 2 in the coagulation sedimentation tank 11.

図２は、本発明の水処理装置を用いた水処理方法の他の一例のフローチャートである。図２に示した水処理装置２１は、図１に示した水処理装置のより好ましい態様である。図１に示した水処理装置に加えて、図２に示した水処理装置２１では、凝集沈殿槽１１の上流に生物膜処理槽１４を備え、原水１を生物膜処理槽１４に導入および通過させて生物膜処理水５を得て、生物膜処理水５を被処理水２として凝集沈殿槽１１に導入する。
以下、本発明の水処理装置を構成する各部分の好ましい態様を説明する。 FIG. 2 is a flowchart of another example of a water treatment method using the water treatment apparatus of the present invention. The water treatment device 21 shown in FIG. 2 is a more preferable embodiment of the water treatment device shown in FIG. In addition to the water treatment apparatus shown in FIG. 1, the water treatment apparatus 21 shown in FIG. 2 is provided with a biological membrane treatment tank 14 upstream of the coagulation sedimentation tank 11, and the raw water 1 is introduced and passed through the biological membrane treatment tank 14. The biological membrane treated water 5 is obtained, and the biological membrane treated water 5 is introduced into the coagulation sedimentation tank 11 as the water to be treated 2.
Hereinafter, preferred embodiments of each part constituting the water treatment apparatus of the present invention will be described.

＜被処理水＞
被処理水として、原水をそのまま用いてもよく、必要に応じて適当な前処理をした水を用いてもよい。前処理としては、有機物を十分に除去する観点から、生物処理が好ましい。原水を生物処理して得られた生物処理水としては、原水を活性汚泥処理して得られた活性汚泥処理水や原水を生物膜処理して得られた生物膜処理水が挙げられる。返送汚泥の管理が不要になる観点から、生物膜処理水であることが好ましい。 <Water to be treated>
As the water to be treated, raw water may be used as it is, or water that has been appropriately pretreated may be used if necessary. As the pretreatment, biological treatment is preferable from the viewpoint of sufficiently removing organic substances. Examples of the biologically treated water obtained by biologically treating the raw water include activated sludge treated water obtained by treating the raw water with activated sludge and biological membrane treated water obtained by treating the raw water with a biological membrane. Biofilm treated water is preferable from the viewpoint of eliminating the need for management of returned sludge.

原水は、特に制限はなく、例えば生活排水、下水、食品工場や製紙工場の排水等の様々な種類の排水を、原水として用いることができる。原水は、有機性排水であることが好ましい。製紙工場の排水の中でも、紙パルプ工場の排水を好ましく用いられる。
原水の濃度は特に制限はなく、広い濃度範囲の排水に適用できる。
原水のｐＨは５．０〜８．０であることが好ましく、６．０〜７．０であることがより好ましい。 The raw water is not particularly limited, and various types of wastewater such as domestic wastewater, sewage, and wastewater from food factories and paper mills can be used as raw water. The raw water is preferably organic wastewater. Among the wastewater from paper mills, the wastewater from pulp and paper mills is preferably used.
The concentration of raw water is not particularly limited and can be applied to wastewater in a wide concentration range.
The pH of the raw water is preferably 5.0 to 8.0, more preferably 6.0 to 7.0.

＜生物膜処理槽＞
本発明の水処理装置は、原水のＣＯＤなどの有機物濃度を低減させた被処理水を得る観点から、生物膜処理槽を備えることが好ましい。生物膜処理槽の位置は特に制限はないが、凝集沈殿槽の上流に生物膜処理槽を備えることが好ましい。生物膜処理槽は特に制限はないが、曝気手段を少なくとも備えることが好ましい。生物膜処理槽において微生物を担持する担体は、固定床式、流動床式、展開床式のなど任意の微生物床方式とすることができるが、流動床式または固定床式であることが好ましい。担体としては特に制限はなく、活性炭、種々のプラスチック担体、スポンジ担体などがいずれも使用できる。生物膜処理槽には、公知の曝気手段を用いることができる。
水処理装置が備える生物膜処理槽の数に制限はなく、１槽式でも２槽以上の多段式であってもよい。 <Biofilm treatment tank>
The water treatment apparatus of the present invention preferably includes a biofilm treatment tank from the viewpoint of obtaining water to be treated with a reduced concentration of organic substances such as COD in raw water. The position of the biofilm treatment tank is not particularly limited, but it is preferable to provide the biofilm treatment tank upstream of the coagulation sedimentation tank. The biofilm treatment tank is not particularly limited, but it is preferable that the biofilm treatment tank is provided with at least aeration means. The carrier that carries the microorganisms in the biofilm treatment tank can be any microbial bed type such as a fixed bed type, a fluidized bed type, and a developed bed type, but a fluidized bed type or a fixed bed type is preferable. The carrier is not particularly limited, and activated carbon, various plastic carriers, sponge carriers and the like can be used. A known aeration means can be used for the biofilm treatment tank.
The number of biofilm treatment tanks provided in the water treatment device is not limited, and may be a one-tank type or a multi-stage type having two or more tanks.

＜凝集沈殿槽＞
本発明の水処理装置は、被処理水に凝集剤を添加して凝集処理水を得る凝集沈殿槽を備え、凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである。凝集沈殿槽により、得られた凝集処理水にフロックを形成することが好ましい。
水処理装置が備える凝集沈殿槽の数に制限はないが、本発明では水処理装置が、凝集沈殿槽を１つのみ備えることが好ましい。 <Coagulation sedimentation tank>
The water treatment apparatus of the present invention includes a coagulation-sedimentation tank for obtaining coagulation-treated water by adding a coagulant to the water to be treated, and the water area load of the coagulation-sedimentation tank is 12 to 48 m / D. It is preferable to form flocs in the obtained coagulation-treated water by a coagulation sedimentation tank.
Although the number of coagulation and settling tanks provided in the water treatment device is not limited, it is preferable that the water treatment device includes only one coagulation and settling tank in the present invention.

凝集沈殿槽の水面積負荷の下限値は、土地面積が限られる問題や設備コストの問題を抑制する観点から、２０ｍ／Ｄ以上であることが好ましく、３０ｍ／Ｄ以上であることがより好ましく、３５ｍ／Ｄ以上であることが特に好ましい。凝集沈殿槽の水面積負荷の上限値は、フラックスを大きくし、ろ過膜の閉塞を抑制して安定運転する観点から、４５ｍ／Ｄ以下であることが好ましく、なるべく小さいことがより好ましい。なお、凝集沈殿槽の水面積負荷の単位は、ｍ３／ｍ２／Ｄａｙと記載されることもある。 The lower limit of the water area load of the coagulation sedimentation tank is preferably 20 m / D or more, more preferably 30 m / D or more, from the viewpoint of suppressing the problem of limited land area and the problem of equipment cost. It is particularly preferable that it is 35 m / D or more. The upper limit of the water area load of the coagulation sedimentation tank is preferably 45 m / D or less, and more preferably as small as possible, from the viewpoint of increasing the flux, suppressing clogging of the filtration membrane, and performing stable operation. The unit of the water area load of the coagulation sedimentation tank may be described as m 3 / m 2 / Day.

凝集剤としては、無機凝集剤および高分子凝集剤を挙げることができる。本発明では、凝集剤が無機凝集剤であることが好ましい。
無機凝集剤は、アルミニウム系凝集剤または鉄系凝集剤であることが好ましく、アルミニウム系凝集剤であることがより好ましい。無機凝集剤としては、硫酸アルミニウム（硫酸バンド）、ポリ塩化アルミニウム（ＰＡＣ）、塩化第二鉄、硫酸第一鉄、ポリ硫酸鉄、ポリシリカ鉄が例示される。これらの中でも、硫酸バンドおよびＰＡＣが好ましく、ＰＡＣがより好ましい。
なお、高分子凝集剤としては、両性高分子凝集剤、ノニオン性高分子凝集剤、アニオン性高分子凝集剤、カチオン性高分子凝集剤などを挙げることができる。本発明では、凝集剤として高分子凝集剤を含まないことが好ましい。高分子凝集剤を使わない場合、高分子凝集剤がろ過膜に付着して不可逆的な閉塞が起きることもない。さらに、限外ろ過膜の膜ろ過処理時に通常実施されていた、無機凝集剤および高分子凝集剤の混合の前処理も不要となる。なお、高分子凝集剤を使わない結果、仮に固液分離が不十分になると凝集沈殿槽からの流出物質がろ過膜を閉塞させ維持管理が困難になるという懸念があった。本発明では、生物膜処理における通常の凝集沈殿槽の設計値よりも水面積負荷を小さく設計することによって、高分子凝集剤を用いずに凝集物の沈降速度を高めて固液分離を確実に行い、凝集沈殿槽からの流出物質および高分子凝集剤の両方に起因するろ過膜の閉塞を同時に抑制できる。 Examples of the flocculant include an inorganic flocculant and a polymer flocculant. In the present invention, the flocculant is preferably an inorganic flocculant.
The inorganic flocculant is preferably an aluminum-based flocculant or an iron-based flocculant, and more preferably an aluminum-based flocculant. Examples of the inorganic flocculant include aluminum sulfate (sulfate band), polyaluminum chloride (PAC), ferric chloride, ferrous sulfate, polyiron sulfate, and polysilica iron. Among these, sulfate band and PAC are preferable, and PAC is more preferable.
Examples of the polymer flocculant include an amphoteric polymer flocculant, a nonionic polymer flocculant, an anionic polymer flocculant, and a cationic polymer flocculant. In the present invention, it is preferable that the flocculant does not contain a polymer flocculant. When the polymer flocculant is not used, the polymer flocculant does not adhere to the filtration membrane and cause irreversible blockage. Further, the pretreatment for mixing the inorganic flocculant and the polymer flocculant, which is usually performed during the membrane filtration treatment of the ultrafiltration membrane, becomes unnecessary. As a result of not using the polymer flocculant, there is a concern that if the solid-liquid separation becomes insufficient, the outflow material from the coagulation sedimentation tank will block the filtration membrane and maintenance will be difficult. In the present invention, by designing the water area load to be smaller than the design value of a normal coagulation sedimentation tank in biofiltration treatment, the sedimentation rate of agglomerates is increased without using a polymer coagulant to ensure solid-liquid separation. This can simultaneously suppress the blockage of the filtration membrane caused by both the outflow material from the coagulation sedimentation tank and the polymer flocculant.

＜ろ過膜＞
本発明の水処理装置は、凝集処理水を膜ろ過して処理水を得るろ過膜を備える。本発明では、ろ過膜が精密ろ過膜または限外ろ過膜であることが好ましく、限外ろ過膜であることがより好ましい。
精密ろ過膜の開口径は特に制限はなく、０．１〜０．５μｍであることが好ましく、０．１〜０．２μｍであることがより好ましい。限外ろ過膜の開口径は特に制限はなく、０．０１〜０．０５μｍであることが好ましく、０．０１〜０．０２μｍであることがより好ましい。
ろ過膜の形状は特に制限はなく、例えば中空糸膜、スパイラル膜、プリーツ膜、平膜などを挙げることができる。ろ過膜が、中空糸膜であることが好ましい。
ろ過膜の配置位置は、ろ過膜モジュールの内部であることが好ましく、具体的にはろ過膜が生物処理槽の内部以外（外部）に配置されることが好ましく、活性汚泥槽の内部以外に配置されることがより好ましい。すなわち、ろ過膜は、膜分離活性汚泥法に用いられる生物処理槽の内部に配置されたろ過膜ではないことが好ましい。ろ過膜の配置位置をろ過膜モジュールの内部とすることで、ブロワなどの曝気手段が必要ではなくなり、電気代を抑制して運転コストを抑制できる。また、ろ過膜の配置位置をろ過膜モジュールの内部とすることで、ろ過膜を容易に増設しやすくでき、処理水量を増やす等の調整を容易にしやすくなる。 <Filtration membrane>
The water treatment apparatus of the present invention includes a filtration membrane that obtains treated water by membrane filtration of coagulated treated water. In the present invention, the filtration membrane is preferably a microfiltration membrane or an ultrafiltration membrane, and more preferably an ultrafiltration membrane.
The opening diameter of the microfiltration membrane is not particularly limited, and is preferably 0.1 to 0.5 μm, more preferably 0.1 to 0.2 μm. The opening diameter of the ultrafiltration membrane is not particularly limited, and is preferably 0.01 to 0.05 μm, more preferably 0.01 to 0.02 μm.
The shape of the filtration membrane is not particularly limited, and examples thereof include a hollow fiber membrane, a spiral membrane, a pleated membrane, and a flat membrane. The filtration membrane is preferably a hollow fiber membrane.
The position of the filtration membrane is preferably inside the filtration membrane module, specifically, the filtration membrane is preferably placed outside the inside (outside) of the biological treatment tank, and is placed outside the inside of the activated sludge tank. It is more preferable to be done. That is, it is preferable that the filtration membrane is not a filtration membrane arranged inside the biological treatment tank used in the membrane separation activated sludge method. By arranging the filtration membrane inside the filtration membrane module, an aeration means such as a blower is not required, and the electricity bill can be suppressed and the operating cost can be suppressed. Further, by arranging the filtration membrane inside the filtration membrane module, it becomes easy to add the filtration membrane, and it becomes easy to make adjustments such as increasing the amount of treated water.

＜処理水＞
ろ過膜を通過した処理水は、少なくとも一部が貯留手段に貯留され、逆洗浄に用いられる。なお、処理水の一部は、貯留手段に貯留されずにそのまま逆浸透膜に供給してもよい。ただし、ろ過膜を通過した処理水の全部が貯留手段に貯留され、貯留手段に貯留された処理水の一部がそのまま逆浸透膜に供給されて、残りが逆洗浄用に貯留されることが好ましい。
ろ過膜を通過した処理水は、浮遊物質（ｓｕｓｐｅｎｄｅｄ ｓｏｌｉｄｓ；ＳＳ）が十分に除去されるため、そのまま逆浸透膜に供給することができる。 <Treatd water>
At least a part of the treated water that has passed through the filtration membrane is stored in the storage means and used for backwashing. A part of the treated water may be supplied to the reverse osmosis membrane as it is without being stored in the storage means. However, all of the treated water that has passed through the filtration membrane may be stored in the storage means, a part of the treated water stored in the storage means may be supplied to the reverse osmosis membrane as it is, and the rest may be stored for backwashing. preferable.
The treated water that has passed through the filtration membrane can be supplied to the reverse osmosis membrane as it is because suspended solids (SS) are sufficiently removed.

＜その他の装置＞
水処理装置は、その他の機能を有する部分を備えていてもよい。 <Other devices>
The water treatment device may include parts having other functions.

水処理装置は、凝集処理手段の上流に、ｐＨ調整手段を備えていてもよい。ｐＨ調整手段の位置は特に制限はない。ｐＨ調整手段では、被処理水のｐＨを５．０〜８．０に調整することが好ましく、６．０〜７．０に調整することがより好ましい。なお、原水のｐＨが５．０〜８．０で無機凝集剤の凝集域である場合、ｐＨ調整手段を設けなくてもよい。 The water treatment apparatus may be provided with a pH adjusting means upstream of the coagulation treatment means. The position of the pH adjusting means is not particularly limited. In the pH adjusting means, it is preferable to adjust the pH of the water to be treated to 5.0 to 8.0, and more preferably to adjust it to 6.0 to 7.0. When the pH of the raw water is 5.0 to 8.0 and it is in the aggregation region of the inorganic flocculant, it is not necessary to provide the pH adjusting means.

水処理装置は、凝集処理手段の上流に、被処理水のＣＯＤなどの水質を測定する水質測定手段を備えていてもよい。水処理装置は、水質測定手段で測定したＣＯＤなどの値に基づいて凝集剤の添加量を制御する凝集剤の添加量制御手段を備えていてもよい。
水処理装置は、ろ過膜を逆洗浄する逆洗手段を備えることが好ましい。逆洗（逆洗浄）は、空気や洗浄流体などを用いることができ、洗浄流体を用いることが好ましい。逆洗頻度は５〜３０分毎であることが好ましく、１０〜２０分毎であることがより好ましい。
水処理装置は、薬品を用いたＣＩＰ（クリーニングインプレイス洗浄）洗浄を行う手段を有することが好ましい。薬品を用いたＣＩＰ洗浄は水処理を止めて水処理装置の系内に薬品を循環させることが好ましい。薬品を用いたＣＩＰ洗浄に用いられる薬品は酸、アルカリまたは洗浄剤であることが好ましい。被処理水が鉱物を多く含む場合は、酸が好ましい。酸としては、塩酸や硫酸、硝酸、クエン酸、シュウ酸、ＥＤＴＡなどを挙げることができる。被処理水が有機物を多く含む場合はアルカリであることが好ましい。また、薬品は、限外ろ過膜への耐性を有する洗浄剤であることが好ましい。アルカリや洗浄剤としては、次亜塩素酸またはその塩、水酸化ナトリウム、過酸化水素水などを挙げることができ、次亜塩素酸ナトリウムであることが好ましい。
本発明の水処理装置によれば、逆洗を定期的に行うのみで薬品洗浄をせずに連続運転できる、いわゆる延べ連続運転時間を長くすることができる。 The water treatment apparatus may be provided with a water quality measuring means for measuring the water quality such as COD of the water to be treated, upstream of the coagulation treatment means. The water treatment apparatus may include a means for controlling the amount of the coagulant added, which controls the amount of the coagulant added based on a value such as COD measured by the water quality measuring means.
The water treatment apparatus preferably includes a backwashing means for backwashing the filtration membrane. For backwashing (backwashing), air, a washing fluid, or the like can be used, and it is preferable to use a washing fluid. The backwash frequency is preferably every 5 to 30 minutes, more preferably every 10 to 20 minutes.
The water treatment apparatus preferably has means for performing CIP (cleaning-in-place cleaning) cleaning using chemicals. For CIP cleaning using chemicals, it is preferable to stop the water treatment and circulate the chemicals in the system of the water treatment apparatus. The chemicals used for CIP cleaning with chemicals are preferably acids, alkalis or cleaning agents. Acids are preferred when the water to be treated contains a large amount of minerals. Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, citric acid, oxalic acid, EDTA and the like. When the water to be treated contains a large amount of organic substances, it is preferably alkaline. Further, the chemical is preferably a cleaning agent having resistance to the ultrafiltration membrane. Examples of the alkali and the cleaning agent include hypochlorous acid or a salt thereof, sodium hydroxide, hydrogen peroxide solution and the like, and sodium hypochlorite is preferable.
According to the water treatment apparatus of the present invention, it is possible to prolong the so-called total continuous operation time, in which continuous operation can be performed without chemical cleaning only by performing backwashing periodically.

水処理装置は、ろ過膜の下流に、さらに処理水を透過して透過水を得られる逆浸透膜を備えることが好ましい。逆浸透膜の開口径は特に制限はなく、０．００１〜０．００５μｍであることが好ましく、０．００１〜０．００２μｍであることがより好ましい。逆浸透膜の材料としては特に制限はなく、例えばポリアミド膜などを用いることができる。
水処理装置によって、処理水を逆浸透膜処理し、透過水（回収水とも言われる）として回収して、再利用することができる。例えば、工場からの排水を工業用水並みの水質の透過水として回収し、用水（工業用水）として再利用することができる。また、透過水は、無菌水として再利用することができる。 The water treatment apparatus preferably includes a reverse osmosis membrane downstream of the filtration membrane, which can further permeate the treated water to obtain permeated water. The opening diameter of the reverse osmosis membrane is not particularly limited, and is preferably 0.001 to 0.005 μm, more preferably 0.001 to 0.002 μm. The material of the reverse osmosis membrane is not particularly limited, and for example, a polyamide membrane or the like can be used.
The treated water can be treated with a reverse osmosis membrane by a water treatment device, recovered as permeated water (also referred to as recovered water), and reused. For example, wastewater from a factory can be recovered as permeated water having the same water quality as industrial water and reused as water (industrial water). In addition, the permeated water can be reused as sterile water.

［水処理装置の製造方法］
水処理装置の製造方法は特に制限はない。
例えば、水処理装置の製造方法は、水面積負荷が１２〜４８ｍ／Ｄである沈殿槽を備える既存設備に対して、沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程と、凝集沈殿槽の下流にろ過膜を連結する工程とを含むことが好ましい。または、水面積負荷が１２〜４８ｍ／Ｄである沈殿槽とろ過膜とを備える既存設備に対して、沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程を含むことが好ましい。
さらに、水処理装置の製造方法は、既存設備が、生物処理槽、水面積負荷が１２〜４８ｍ／Ｄである沈殿槽を備える既存設備である場合に、生物処理槽に担体を導入して生物膜処理槽とする工程と、沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程と、凝集沈殿槽の下流にろ過膜を連結する工程とを含むことがより好ましい。
従来、このように水面積負荷が１２〜４８ｍ／Ｄである（凝集剤を用いない）沈殿槽を凝集沈殿槽とすることは検討されていなかった。稼働率の低い（凝集剤を用いない）沈殿槽を本発明の水処理装置に改変することによって、放流排水の再処理のために生物処理水などをろ過膜でさらに高度処理して回収できるように転用することは、産業上の利用可能性が高い。 [Manufacturing method of water treatment equipment]
The manufacturing method of the water treatment device is not particularly limited.
For example, the method for manufacturing a water treatment apparatus includes a step of providing a coagulant addition means in the settling tank to form a coagulation settling tank for an existing facility equipped with a settling tank having a water area load of 12 to 48 m / D. It is preferable to include a step of connecting the filtration membrane downstream of the settling tank. Alternatively, it is preferable to include a step of providing a coagulant addition means in the settling tank to form a coagulation settling tank for an existing facility provided with a settling tank having a water area load of 12 to 48 m / D and a filtration membrane.
Further, the method for manufacturing the water treatment apparatus is that when the existing equipment is an existing equipment equipped with a biological treatment tank and a settling tank having a water area load of 12 to 48 m / D, a carrier is introduced into the biological treatment tank to form a living organism. It is more preferable to include a step of forming a membrane treatment tank, a step of providing a coagulant adding means in the settling tank to form a coagulation sedimentation tank, and a step of connecting a filtration membrane downstream of the coagulation sedimentation tank.
Conventionally, it has not been studied to use a settling tank having a water area load of 12 to 48 m / D (without using a coagulant) as a coagulation settling tank. By modifying the settling tank with a low operating rate (without using a flocculant) to the water treatment apparatus of the present invention, biologically treated water and the like can be further treated with a filtration membrane for recovery of discharged wastewater. Diversion to is highly industrial applicability.

［水処理方法］
本発明の水処理方法は、被処理水に凝集剤を添加して凝集沈殿槽を通過させて凝集処理水を得る凝集沈殿工程と、凝集処理水をろ過膜で膜ろ過して処理水を得る膜ろ過工程を備え、凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである。
本発明の水処理方法の好ましい態様は、本発明の水処理装置の好ましい態様と同様である。 [Water treatment method]
The water treatment method of the present invention includes a coagulation-sedimentation step in which a coagulant is added to water to be treated and passed through a coagulation-sedimentation tank to obtain coagulation-treated water, and coagulation-treated water is membrane-filtered with a filtration membrane to obtain treated water. It is provided with a membrane filtration step, and the water area load of the coagulation sedimentation tank is 12 to 48 m / D.
The preferred embodiment of the water treatment method of the present invention is the same as the preferred embodiment of the water treatment apparatus of the present invention.

以下に実施例と比較例を挙げて本発明をさらに具体的に説明する。以下の実施例に示す材料、使用量、割合、処理内容、処理手順等は、本発明の趣旨を逸脱しない限り適宜変更することができる。従って、本発明の範囲は以下に示す具体例により限定的に解釈されるべきものではない。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, proportions, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

［実施例１］
活性汚泥法用の活性汚泥槽（曝気槽）、水面積負荷が１２〜４８ｍ／Ｄである（凝集剤を用いない）沈殿槽とを備える既存設備に対して、活性汚泥槽に流動担体を導入して生物膜処理槽とする工程と、沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程と、凝集沈殿槽の下流にろ過膜を連結する工程を行って、図２に記載の水処理装置を製造した。
図２に記載の水処理装置を用いて、製紙工場の排水（紙パルプ工場からの白水）を原水として、以下の水処理を行った。原水のｐＨは６．０〜７．０であった。
まず、原水１に対して、流動床担体を用いた流動方式の生物膜処理槽１４を用いて曝気しながら生物膜処理を行い、得られた生物膜処理水５を被処理水２とした。 [Example 1]
Introduced a fluid carrier into the activated sludge tank for existing equipment equipped with an activated sludge tank (exhaustion tank) for the activated sludge method and a settling tank with a water area load of 12 to 48 m / D (without using a flocculant). A step of forming a biological membrane treatment tank, a step of providing a coagulant addition means in the settling tank to form a coagulation sedimentation tank, and a step of connecting a filtration membrane downstream of the coagulation sedimentation tank are performed, as shown in FIG. Manufactured a water treatment device.
Using the water treatment apparatus shown in FIG. 2, the following water treatment was performed using wastewater from a paper mill (white water from a pulp and paper mill) as raw water. The pH of the raw water was 6.0-7.0.
First, the raw water 1 was treated with a biofilm while being aerated using a flow-type biofilm treatment tank 14 using a fluidized bed carrier, and the obtained biofilm-treated water 5 was used as the water to be treated 2.

被処理水２を、水面積負荷が４８ｍ／Ｄとなるように設計した凝集沈殿槽１１に導入した。凝集沈殿槽１１に対し、凝集剤添加手段１２から、無機凝集剤を添加した。無機凝集剤としてＰＡＣを使用した。ＰＡＣは原液濃度１０質量％品を使用した。 The water to be treated 2 was introduced into a coagulation sedimentation tank 11 designed so that the water area load was 48 m / D. An inorganic flocculant was added to the coagulation sedimentation tank 11 from the flocculant addition means 12. PAC was used as the inorganic flocculant. As the PAC, a product having a stock solution concentration of 10% by mass was used.

凝集沈殿槽１１から凝集処理水３を、送水ポンプによりろ過膜１３の一次側に供給し、膜ろ過して処理水４を得た。膜ろ過では、ろ過膜１３として限外ろ過膜であるＯＪＩ−ＭＥＮＢＲＡＮＥ（登録商標）を用いた。限外ろ過膜の逆洗頻度は、１５分毎とした。 The coagulation-treated water 3 was supplied from the coagulation-sedimentation tank 11 to the primary side of the filtration membrane 13 by a water pump, and the membrane was filtered to obtain the treated water 4. In the membrane filtration, OJI-MENBREAN (registered trademark), which is an ultrafiltration membrane, was used as the filtration membrane 13. The frequency of backwashing of the ultrafiltration membrane was every 15 minutes.

［実施例２］
実施例１の水処理において、被処理水の流量を変更して凝集沈殿槽の水面積負荷を３６ｍ／Ｄにした以外は実施例１と同様にして、実施例２の水処理を行った。 [Example 2]
In the water treatment of Example 1, the water treatment of Example 2 was carried out in the same manner as in Example 1 except that the flow rate of the water to be treated was changed to set the water area load of the coagulation sedimentation tank to 36 m / D.

［実施例３］
実施例１の水処理において、被処理水の流量を変更して凝集沈殿槽の水面積負荷を２４ｍ／Ｄにした以外は実施例１と同様にして、実施例３の水処理を行った。 [Example 3]
In the water treatment of Example 1, the water treatment of Example 3 was carried out in the same manner as in Example 1 except that the flow rate of the water to be treated was changed to set the water area load of the coagulation sedimentation tank to 24 m / D.

［実施例４］
実施例１の水処理において、被処理水の流量を変更して凝集沈殿槽の水面積負荷を１２ｍ／Ｄにした以外は実施例１と同様にして、実施例４の水処理を行った。 [Example 4]
In the water treatment of Example 1, the water treatment of Example 4 was carried out in the same manner as in Example 1 except that the flow rate of the water to be treated was changed to set the water area load of the coagulation sedimentation tank to 12 m / D.

［比較例１］
実施例１の水処理において、被処理水の流量を変更して凝集沈殿槽の水面積負荷を５５ｍ／Ｄにした以外は実施例１と同様にして、比較例１の水処理を行った。 [Comparative Example 1]
In the water treatment of Example 1, the water treatment of Comparative Example 1 was carried out in the same manner as in Example 1 except that the flow rate of the water to be treated was changed to set the water area load of the coagulation sedimentation tank to 55 m / D.

［比較例２］
実施例４の水処理において、無機凝集剤を添加しない以外は、実施例４と同様にして、比較例２の水処理を行った。 [Comparative Example 2]
In the water treatment of Example 4, the water treatment of Comparative Example 2 was carried out in the same manner as in Example 4 except that the inorganic flocculant was not added.

［参考例１］
実施例１の水処理において、さらに高分子凝集剤としてアニオン性高分子凝集剤を添加した以外は実施例１と同様にして、参考例１の水処理を行った。 [Reference example 1]
In the water treatment of Example 1, the water treatment of Reference Example 1 was carried out in the same manner as in Example 1 except that an anionic polymer flocculant was further added as a polymer flocculant.

［評価］
各実施例、比較例および参考例の水処理を行った場合の、ろ過膜のフラックス（透過流束）および延べ連続運転時間を求めた。延べ連続運転時間は、水処理の開始から、逆洗浄の直後にろ過膜の差圧が４０〜６０ｋＰａを維持できなくなって連続運転を止めた時点までの時間とした。
各比較例および参考例の水処理では、連続運転を止めた後に酸洗浄および／またはアルカリ洗浄を行い、薬品洗浄効果（薬品を用いたＣＩＰ洗浄効果）を確認した。得られた結果を下記表１に記載した。 [Evaluation]
The flux (permeation flux) of the filtration membrane and the total continuous operation time were determined when the water treatments of the Examples, Comparative Examples and Reference Examples were performed. The total continuous operation time was defined as the time from the start of the water treatment to the time when the differential pressure of the filtration membrane could not be maintained at 40 to 60 kPa immediately after the backwash and the continuous operation was stopped.
In the water treatment of each Comparative Example and Reference Example, acid cleaning and / or alkaline cleaning was performed after the continuous operation was stopped, and the chemical cleaning effect (CIP cleaning effect using chemicals) was confirmed. The results obtained are shown in Table 1 below.

以上より、本発明の水処理装置によれば、フラックスを大きくでき、かつ延べ連続運転時間を長くできることから、有機物や懸濁物で汚染された水から膜ろ過水を得る際に、装置を小型化でき、投資額や設置面積を抑制できることがわかった。
比較例１より、凝集沈殿槽の水面積負荷が本発明で規定する上限値を超える場合、フラックスが小さくなり、延べ連続運転時間も短くなったことから、ろ過膜が閉塞しやすいことがわかった。また、低下したフラックスは酸洗浄によって回復する傾向が見られた。
比較例２より、凝集沈殿槽を用いず、すなわち被処理水に凝集剤を添加しない場合、フラックスが小さくなり、延べ連続運転時間も短くなったことから、ろ過膜が閉塞しやすいことがわかった。また、低下したフラックスはアルカリ洗浄によって回復する傾向が見られた。 From the above, according to the water treatment apparatus of the present invention, the flux can be increased and the total continuous operation time can be lengthened. Therefore, when obtaining membrane-filtered water from water contaminated with organic substances or suspensions, the apparatus can be made smaller. It was found that the investment amount and installation area can be suppressed.
From Comparative Example 1, it was found that when the water area load of the coagulation sedimentation tank exceeds the upper limit specified in the present invention, the flux becomes smaller and the total continuous operation time becomes shorter, so that the filtration membrane is likely to be clogged. .. In addition, the reduced flux tended to be recovered by acid cleaning.
From Comparative Example 2, it was found that when the coagulation sedimentation tank was not used, that is, when the coagulant was not added to the water to be treated, the flux became small and the total continuous operation time became short, so that the filtration membrane was easily clogged. .. In addition, the reduced flux tended to be recovered by alkaline cleaning.

１ 原水
２ 被処理水
３ 凝集処理水
４ 処理水
５ 生物膜処理水
１１ 凝集沈殿槽
１２ 凝集剤添加手段
１３ ろ過膜
１４ 生物膜処理槽
２１ 水処理装置 1 Raw water 2 Processed water 3 Coagulation treated water 4 Treated water 5 Biological membrane treated water 11 Coagulation sedimentation tank 12 Coagulant addition means 13 Filter membrane 14 Biological membrane treatment tank 21 Water treatment device

Claims (12)

被処理水に凝集剤を添加して凝集処理水を得る凝集沈殿槽と、
前記凝集処理水を膜ろ過して処理水を得るろ過膜を備え、
前記凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである、水処理装置。 A coagulation sedimentation tank that obtains coagulation-treated water by adding a coagulant to the water to be treated,
A filtration membrane for obtaining treated water by membrane filtration of the coagulated treated water is provided.
A water treatment apparatus having a water area load of 12 to 48 m / D in the coagulation sedimentation tank. 前記凝集剤が無機凝集剤である、請求項１に記載の水処理装置。 The water treatment apparatus according to claim 1, wherein the flocculant is an inorganic flocculant. 前記無機凝集剤がアルミニウム系凝集剤または鉄系凝集剤である、請求項２に記載の水処理装置。 The water treatment apparatus according to claim 2, wherein the inorganic flocculant is an aluminum-based flocculant or an iron-based flocculant. 前記凝集剤として高分子凝集剤を含まない、請求項１〜３のいずれか一項に記載の水処理装置。 The water treatment apparatus according to any one of claims 1 to 3, which does not contain a polymer flocculant as the flocculant. 前記ろ過膜が限外ろ過膜である、請求項１〜４のいずれか一項に記載の水処理装置。 The water treatment apparatus according to any one of claims 1 to 4, wherein the filtration membrane is an ultrafiltration membrane. 前記水処理装置が、前記凝集沈殿槽を１つのみ備える、請求項１〜５のいずれか一項に記載の水処理装置。 The water treatment device according to any one of claims 1 to 5, wherein the water treatment device includes only one coagulation sedimentation tank. 前記ろ過膜が生物処理槽の内部以外に配置される、請求項１〜６のいずれか一項に記載の水処理装置。 The water treatment apparatus according to any one of claims 1 to 6, wherein the filtration membrane is arranged outside the inside of the biological treatment tank. 前記凝集沈殿槽の上流に生物膜処理槽を備える、請求項１〜７のいずれか一項に記載の水処理装置。 The water treatment apparatus according to any one of claims 1 to 7, further comprising a biofilm treatment tank upstream of the coagulation sedimentation tank. 前記凝集沈殿槽の水面積負荷が２０〜４５ｍ／Ｄである、請求項１〜８のいずれか一項に記載の水処理装置。 The water treatment apparatus according to any one of claims 1 to 8, wherein the water area load of the coagulation sedimentation tank is 20 to 45 m / D. 水面積負荷が１２〜４８ｍ／Ｄである沈殿槽を備える既存設備に対して、
前記沈殿槽に凝集剤添加手段を設けて凝集沈殿槽とする工程と、
凝集沈殿槽の下流にろ過膜を連結する工程とを含む、水処理装置の製造方法。 For existing equipment equipped with a settling tank with a water area load of 12 to 48 m / D
A step of providing a coagulant addition means in the settling tank to form a coagulation settling tank,
A method for manufacturing a water treatment apparatus, which comprises a step of connecting a filtration membrane downstream of a coagulation sedimentation tank. 被処理水に凝集剤を添加して凝集沈殿槽を通過させて凝集処理水を得る凝集沈殿工程と、
前記凝集処理水をろ過膜で膜ろ過して処理水を得る膜ろ過工程を備え、
前記凝集沈殿槽の水面積負荷が１２〜４８ｍ／Ｄである、水処理方法。 A coagulation sedimentation step of adding a coagulant to the water to be treated and passing it through a coagulation sedimentation tank to obtain coagulation-treated water.
A membrane filtration step of obtaining treated water by membrane filtration of the aggregated treated water with a filtration membrane is provided.
A water treatment method in which the water area load of the coagulation sedimentation tank is 12 to 48 m / D. 前記凝集剤が無機凝集剤であり、かつ、前記凝集剤として高分子凝集剤を含まない、請求項１１に記載の水処理方法。 The water treatment method according to claim 11, wherein the flocculant is an inorganic flocculant and does not contain a polymer flocculant as the flocculant.
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