JP5714419B2 - Long fiber filtration device backwash method and long fiber filtration device backwash device - Google Patents

Long fiber filtration device backwash method and long fiber filtration device backwash device Download PDF

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JP5714419B2
JP5714419B2 JP2011131902A JP2011131902A JP5714419B2 JP 5714419 B2 JP5714419 B2 JP 5714419B2 JP 2011131902 A JP2011131902 A JP 2011131902A JP 2011131902 A JP2011131902 A JP 2011131902A JP 5714419 B2 JP5714419 B2 JP 5714419B2
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JP2013000629A (en
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大輔 田坂
大輔 田坂
横山 徹
徹 横山
清水 和彦
和彦 清水
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Organo Corp
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Description

本発明は、下水処理水等の原水中の懸濁物質等を除去するための長繊維ろ過装置の逆洗方法および逆洗装置に関する。   The present invention relates to a backwashing method and a backwashing apparatus for a long fiber filtration device for removing suspended substances in raw water such as sewage treated water.

従来より、下水処理施設等の各種処理工程において、原水中の懸濁物質(SS)等を除去するためのろ過処理として、長繊維束をろ過材として用いたろ過処理が知られている。   Conventionally, in various treatment processes such as sewage treatment facilities, a filtration treatment using a long fiber bundle as a filter medium is known as a filtration treatment for removing suspended substances (SS) and the like in raw water.

例えば、特許文献1および特許文献2には、ろ過装置内部の下方部に支持体を設け、当該支持体の上部に長繊維束の下端を固定するとともに、その上端を自由端としたろ過体を形成し、長繊維束の上端から下端に向かって下降流で原水を通水して、長繊維束内の空隙部により原水中の懸濁物質等を捕捉するろ過装置が記載されている。   For example, in Patent Document 1 and Patent Document 2, a support body is provided at the lower part inside the filtration device, and the lower end of the long fiber bundle is fixed to the upper part of the support body, and the filter body having the upper end as a free end is provided. A filtration device is described that forms and feeds raw water in a downward flow from the upper end to the lower end of the long fiber bundle, and traps suspended substances and the like in the raw water by the voids in the long fiber bundle.

この長繊維束を用いた長繊維ろ材は比表面積が大きく、ろ過抵抗が小さいため、高速かつ高能力のろ過を行うことができるろ材として注目され、特に浄水処理における粗ろ過や下水の三次処理等に利用されている。   The long-fiber filter medium using this long-fiber bundle has a large specific surface area and low filtration resistance, so it has attracted attention as a filter medium that can perform high-speed and high-capacity filtration. Has been used.

このような長繊維ろ材を用いたろ過装置において長時間ろ過を行うと、原水中の懸濁物質等がろ材に堆積してろ過性能が劣化(特にろ過抵抗が増大)するため、ろ材に対してろ過方向と逆の方向に洗浄水等の洗浄液を通過させて堆積した懸濁物質等を除去する、いわゆる逆洗という洗浄が行われる。   When filtration is performed for a long time in a filtration device using such a long fiber filter medium, suspended substances in raw water accumulate on the filter medium and the filtration performance deteriorates (especially the filtration resistance increases). Washing called so-called backwashing is performed in which a suspended liquid or the like is removed by passing a washing solution such as washing water in a direction opposite to the filtration direction.

長繊維ろ材は、その一端が支持体に固定されているので高速に逆洗を行うことができ、その洗浄時間(逆洗時間)が短時間で済むという特徴がある。しかし、継続してろ過を行うと、長繊維ろ材内には微生物に由来する付着物やその他有機物や金属等が付着し始める。この付着物等は上記のような通常の逆洗を行っても除去が困難である。   Since one end of the long fiber filter medium is fixed to the support, backwashing can be performed at high speed, and the washing time (backwashing time) is short. However, if filtration is continued, deposits derived from microorganisms, other organic substances, metals, etc. begin to adhere to the long fiber filter medium. It is difficult to remove these deposits and the like even if the above normal backwashing is performed.

そこで、このような微生物由来の付着物等を効果的に除去または付着防止するために一般に殺菌洗浄が行われる。この殺菌洗浄には、例えば特許文献3のように、逆洗用の洗浄水(逆洗水)に塩素系殺菌剤等の殺菌剤を添加して逆洗を行うものがある。この場合、通常、逆洗後の排水(逆洗排水)中の残留塩素濃度が0.5〜数mg/Lとなるように殺菌剤の添加量が調整される。   Therefore, in order to effectively remove or prevent such deposits derived from microorganisms, sterilization washing is generally performed. As this sterilization cleaning, for example, as in Patent Document 3, backwashing is performed by adding a sterilizing agent such as a chlorine-based sterilizing agent to cleaning water for backwashing (backwashing water). In this case, the addition amount of the bactericide is usually adjusted so that the residual chlorine concentration in the waste water after back washing (back washing waste water) is 0.5 to several mg / L.

このように従来の技術では、逆洗時に殺菌剤として次亜塩素酸ナトリウム等の塩素系殺菌剤を添加する場合、逆洗排水中の残留塩素濃度が0.5mg/L以上となるように添加量を制御していた。しかし、この条件で逆洗を行う場合、長繊維ろ材が捕捉した懸濁物質や微生物等により塩素が消費されるため、多量の次亜塩素酸ナトリウム等を添加しなければならない問題があった。また多量に次亜塩素酸ナトリウム等を添加すると、逆洗排水中の残留塩素濃度が増加するため、長繊維ろ過装置の前段側が生物処理装置である場合、逆洗排水を前段の生物処理槽に戻すと、生物処理に悪影響を及ぼす場合もあった。   Thus, in the conventional technique, when adding a chlorine-based disinfectant such as sodium hypochlorite as a disinfectant during backwashing, the residual chlorine concentration in the backwash wastewater is added to 0.5 mg / L or more. The amount was controlled. However, when backwashing is performed under these conditions, there is a problem that a large amount of sodium hypochlorite or the like must be added because chlorine is consumed by suspended substances or microorganisms captured by the long fiber filter medium. Also, when sodium hypochlorite is added in large quantities, the residual chlorine concentration in the backwash wastewater increases, so if the front side of the long fiber filtration device is a biological treatment device, the backwash wastewater is put into the biological treatment tank in the previous stage. In some cases, the biological treatment could be adversely affected.

また、従来のように逆洗排水中の残留塩素が0.5mg/L程度になるように次亜塩素酸ナトリウム等を添加しても付着物等を除去しきれず、初期のろ過抵抗が上昇する場合があった。さらに、原水によっては逆洗排水中の残留塩素が1.5mg/L以上となるように次亜塩素酸ナトリウム等を添加しても、付着物等を除去しきれず、初期のろ過抵抗が上昇してしまい、通水が困難になる場合があった。   Moreover, even if sodium hypochlorite or the like is added so that the residual chlorine in the backwash wastewater becomes about 0.5 mg / L as in the past, the deposits and the like cannot be removed, and the initial filtration resistance increases. There was a case. Furthermore, depending on the raw water, even if sodium hypochlorite or the like is added so that the residual chlorine in the backwash wastewater is 1.5 mg / L or more, the deposits cannot be removed, and the initial filtration resistance increases. In some cases, it was difficult to pass water.

特開昭63−315110号公報JP-A-63-315110 特開平1−304011号公報Japanese Laid-Open Patent Publication No. 1-304011 特開2006−175342号公報JP 2006-175342 A

本発明の目的は、殺菌剤の添加量を低減し、効率よく長繊維ろ材の洗浄を行うことができる長繊維ろ過装置の逆洗方法および逆洗装置を提供することにある。   An object of the present invention is to provide a backwashing method and a backwashing device for a long fiber filtration device that can reduce the amount of a bactericide added and can efficiently wash a long fiber filter medium.

本発明は、ろ過塔と、前記ろ過塔内部に設けられた支持体と、前記支持体に下端を固定されるとともに、その上端を自由端とした長繊維束とを有する、長繊維束により被処理水中の懸濁物質を捕捉する長繊維ろ過装置の逆洗方法であって、前記長繊維ろ過装置により処理する被処理水が、生物処理を行う生物処理工程と、前記生物処理工程で処理した水を固液分離する固液分離工程とを少なくとも含む生物処理で処理した生物処理水であり、前記長繊維ろ過装置でろ過された水により逆洗を行う第一逆洗工程と、前記第一逆洗工程の後に、前記長繊維ろ過装置でろ過された水および塩素系殺菌剤を含む殺菌剤含有水により逆洗を行う第二逆洗工程と、前記第一逆洗工程で前記ろ過塔から流出された逆洗排水および前記第二逆洗工程で前記ろ過塔から流出された逆洗排水を逆洗排水槽に貯留した後、前記逆洗排水槽に貯留した水を前記生物処理工程および前記生物処理工程の上流側の少なくとも1つに返送する返送工程と、を含み、前記第二逆洗工程における逆洗排水中の残留塩素濃度が1.5〜10mg/Lの範囲になるように前記塩素系殺菌剤を添加する長繊維ろ過装置の逆洗方法である。 The present invention provides a long fiber bundle having a filtration tower, a support provided inside the filtration tower, and a long fiber bundle having a lower end fixed to the support and having an upper end as a free end. A method for backwashing a long fiber filtration device for capturing suspended substances in treated water, wherein the water to be treated to be treated by the long fiber filtration device is treated in a biological treatment step for performing biological treatment and in the biological treatment step. A biologically treated water that has been treated by a biological treatment comprising at least a solid-liquid separation step for separating water into a solid and a liquid; a first backwashing step in which backwashing is performed with water filtered by the long fiber filtration device; and the first After the backwashing step, from the filtration tower in the second backwashing step in which backwashing is performed with the water filtered by the long fiber filtration device and the bactericide-containing water containing the chlorine-based bactericide, and the first backwashing step. The filtered backwash drainage and the second backwash process After storing the backwash waste water flowing out into the backwash drain tank from a returning step for returning water reserved in the backwash drain tank into at least one upstream of the biological treatment step and the biological treatment step, in only containing backwash method of long fiber filtration device residual chlorine concentration in the backwash effluent in said second backwash step adding the chlorine-based disinfectant to be in the range of 1.5~10mg / L is there.

また、前記長繊維ろ過装置の逆洗方法において、前記第一逆洗工程における洗浄時間が、前記第一逆洗工程における洗浄時間および前記第二逆洗工程における洗浄時間を合わせた全洗浄時間の10〜30%の範囲であることが好ましい。   Further, in the backwashing method of the long fiber filtration device, the washing time in the first backwashing process is the total washing time of the washing time in the first backwashing process and the washing time in the second backwashing process. A range of 10 to 30% is preferable.

また、前記長繊維ろ過装置の逆洗方法において、前記第二逆洗工程の後に、前記長繊維束と殺菌剤とを所定の時間接触させる浸漬工程を含むことが好ましい。   Moreover, in the backwashing method of the said long fiber filtration apparatus, it is preferable after the said 2nd backwashing process to include the immersion process which makes the said long fiber bundle and a disinfectant contact for predetermined time.

また、本発明は、ろ過塔と、前記ろ過塔内部に設けられた支持体と、前記支持体に下端を固定されるとともに、その上端を自由端とした長繊維束とを有する、長繊維束により被処理水中の懸濁物質を捕捉する長繊維ろ過装置の逆洗装置であって、前記長繊維ろ過装置により処理する被処理水が、生物処理を行う生物処理槽と、前記生物処理槽で処理した水を固液分離する固液分離装置とを少なくとも有する生物処理装置で処理した生物処理水であり、前記ろ過塔内部に前記長繊維ろ過装置でろ過された水を導入して前記ろ過塔を逆洗する逆洗水導入手段と、前記ろ過塔内部に前記長繊維ろ過装置でろ過された水および塩素系殺菌剤を含む殺菌剤含有水を導入して前記ろ過塔を殺菌逆洗する殺菌剤含有水導入手段と、前記殺菌剤含有水による洗浄により発生する逆洗排水中の残留塩素濃度が1.5〜10mg/Lの範囲になるように前記殺菌剤の添加量を制御する殺菌剤添加量制御手段と、記逆洗を行った後に、前記殺菌逆洗を行うように制御する洗浄制御手段と、前記逆洗により前記ろ過塔から流出された逆洗排水および前記殺菌逆洗により前記ろ過塔から流出された殺菌逆洗排水を逆洗排水槽に貯留した後、前記逆洗排水槽に貯留した水を前記生物処理槽および前記生物処理槽の上流側の少なくとも1つに返送する返送手段と、を有する長繊維ろ過装置の逆洗装置である。 Further, the present invention provides a long fiber bundle having a filtration tower, a support provided inside the filtration tower, and a long fiber bundle having a lower end fixed to the support and having an upper end as a free end. Is a backwashing device of a long fiber filtration device that captures suspended substances in the treated water, wherein the treated water to be treated by the long fiber filtration device is a biological treatment tank that performs biological treatment, and the biological treatment tank. Biologically treated water treated with a biological treatment device having at least a solid-liquid separation device for solid-liquid separation of the treated water, and the filtration tower is introduced with water filtered by the long fiber filtration device inside the filtration tower and backwash water introduction means for backwashing and sterilizing backwash the filtration tower by introducing the disinfectant-containing water containing the long fiber filtration is filtered through device water and a chlorine-based germicide inside the filtration tower sterilizing agent and containing water introduction means, washing by the disinfectant-containing water After residual chlorine concentration in the backwash effluent generated Been and fungicides amount control means for controlling the amount of the sterilizing agent to be in the range of 1.5~10mg / L, the pre Kigyaku washing by , a wash control unit, the fungicidal backwash effluent flowing out of the filtration tower by backwash waste water and the sterilizing backwash flowing out from the filtration tower by the backwash reverse for controlling to perform said disinfecting backwash A backwashing device for a long-fiber filtration device comprising: a storage unit that stores the water stored in the backwashing drainage tank and then returns the water stored in the backwashing drainage tank to at least one of the biological treatment tank and the upstream side of the biological treatment tank. Device.

また、前記長繊維ろ過装置の逆洗装置において、前記洗浄制御手段は、前記洗浄水による洗浄時間が、前記洗浄水による洗浄時間および前記殺菌剤含有水による洗浄時間を合わせた全洗浄時間の10〜30%の範囲となるように制御することが好ましい。   Further, in the backwashing device of the long fiber filtration device, the washing control means is configured such that the washing time with the washing water is 10 times the total washing time including the washing time with the washing water and the washing time with the disinfectant-containing water. It is preferable to control to be in the range of ˜30%.

また、前記長繊維ろ過装置の逆洗装置において、前記殺菌剤含有水による洗浄の後に前記長繊維束と殺菌剤とを所定の時間接触させる浸漬手段を有することが好ましい。   Moreover, it is preferable that the backwashing apparatus of the said long fiber filtration apparatus has a dipping means which makes the said long fiber bundle and a disinfectant contact for a predetermined time after washing | cleaning with the said disinfectant containing water.

本発明では、長繊維ろ過装置の逆洗において、洗浄水により逆洗を行った後に、殺菌剤含有水により逆洗を行うことにより、殺菌剤の添加量を低減し、効率よく長繊維ろ材の洗浄を行うことができる。   In the present invention, in the backwashing of the long fiber filtration device, after the backwashing with the washing water, the backwashing with the bactericide-containing water reduces the addition amount of the bactericide, and the long fiber filter medium is efficiently removed. Cleaning can be performed.

本発明の実施形態に係るろ過システムの一例を示す概略構成図である。It is a schematic structure figure showing an example of a filtration system concerning an embodiment of the present invention. 本発明の実施形態に係る水処理システムの一例を示す概略構成図である。It is a schematic structure figure showing an example of a water treatment system concerning an embodiment of the present invention. 本発明の実施例における全逆洗時間に対する経過時間と逆洗排水SSとの関係を示す図である。It is a figure which shows the relationship between the elapsed time with respect to the total backwash time in the Example of this invention, and the backwash drainage SS.

本発明の実施の形態について以下説明する。本実施形態は本発明を実施する一例であって、本発明は本実施形態に限定されるものではない。   Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

本発明の実施形態に係るろ過システムの一例の概略を図1に示し、その構成について説明する。ろ過システム1は、原水槽10と、長繊維ろ過装置12と、処理水槽14と、逆洗排水槽16と、殺菌剤貯槽18とを備える。   An outline of an example of a filtration system according to an embodiment of the present invention is shown in FIG. 1 and the configuration thereof will be described. The filtration system 1 includes a raw water tank 10, a long fiber filtration device 12, a treated water tank 14, a backwash drainage tank 16, and a disinfectant storage tank 18.

図1のろ過システム1において、原水槽10には配管52が接続され、原水槽10と長繊維ろ過装置12の上方部とがポンプ28、バルブ38を介して配管54により、長繊維ろ過装置12の下方部と処理水槽14とがバルブ42を介して配管56により、処理水槽14と長繊維ろ過装置12の下方部とがポンプ30、バルブ46を介して配管64により、長繊維ろ過装置12の上方部と逆洗排水槽16とがバルブ40を介して配管58により接続され、処理水槽14にはポンプ34、バルブ44を介して配管62が接続され、逆洗排水槽16にはポンプ32を介して配管60が接続されている。長繊維ろ過装置12の下方部には気体供給装置としてブロワ20がバルブ50を介して配管68により接続されている。配管64のバルブ46の下流側には殺菌剤貯槽18がポンプ36、バルブ48を介して配管66により接続されている。配管58のバルブ40の上流側および逆洗排水槽16には殺菌剤濃度測定装置24,26がそれぞれ設置されている。殺菌剤濃度測定装置24はポンプ36と電気的接続手段等により接続されている。長繊維ろ過装置12には圧力測定装置として差圧計22が設置されている。長繊維ろ過装置12は、ろ過塔70と、ろ過塔70内部の下方部に設けられた支持体74と、長繊維ろ材として、支持体74に下端を固定されるとともに、その上端を自由端とした1つまたは複数の長繊維束72とを有する。通常は、長繊維束72はろ過塔70内に充満するように充填される。   In the filtration system 1 of FIG. 1, a pipe 52 is connected to the raw water tank 10, and the raw water tank 10 and the upper part of the long fiber filtration device 12 are connected by a pipe 54 via a pump 28 and a valve 38. Of the long fiber filtration device 12 by the pipe 56 through the valve 42, and the lower part of the treatment water tank 14 and the long fiber filtration device 12 by the pipe 64 through the pump 30 and the valve 46. The upper part and the backwash drain 16 are connected by a pipe 58 via a valve 40, a pump 34 is connected to the treated water tank 14, a pipe 62 is connected via a valve 44, and a pump 32 is connected to the backwash drain 16. A pipe 60 is connected via the cable. A blower 20 as a gas supply device is connected to a lower portion of the long fiber filtration device 12 through a valve 50 through a valve 50. The disinfectant storage tank 18 is connected to the downstream side of the valve 46 of the pipe 64 by a pipe 66 through a pump 36 and a valve 48. Disinfectant concentration measuring devices 24 and 26 are installed on the upstream side of the valve 40 of the pipe 58 and the backwash drain 16 respectively. The disinfectant concentration measuring device 24 is connected to the pump 36 by an electrical connection means or the like. The long fiber filtration device 12 is provided with a differential pressure gauge 22 as a pressure measuring device. The long fiber filtration device 12 includes a filtration tower 70, a support 74 provided in a lower portion inside the filtration tower 70, and a long fiber filter medium having a lower end fixed to the support 74 and an upper end thereof as a free end. One or a plurality of long fiber bundles 72. Normally, the long fiber bundle 72 is packed so as to fill the filtration tower 70.

ろ過システム1の動作について、図1を参照して説明する。   The operation of the filtration system 1 will be described with reference to FIG.

(i)ろ過工程
被処理水である原水は配管52を通して原水槽10に供給、貯留される。バルブ38,42が開状態、バルブ40,44,46,48,50が閉状態とされて、ポンプ28が運転されることにより、原水は配管54を通して長繊維ろ過装置12のろ過塔70内部に上方部から供給される。当初、水中で全体的にほぼ直立した状態となっていた長繊維束72は、自重および原水の水流により屈曲して、その高さが縮んだ状態となる。ろ過塔70の上方部から流入された原水は、ろ過塔70の上方部から下方部に向かって、すなわち長繊維束72の上端から下端に向かって下降流で通過し、長繊維束72の空隙部等により原水中の懸濁物質等が捕捉される。清澄となった処理水はろ過塔70の下方部から流出され、配管56を通って処理水槽14に流入される。処理水槽14の水位が所定の高さより高くなった場合は、バルブ44が開状態とされ、ポンプ34が運転されることにより、処理水は処理水槽14から配管62を通して排出される。処理水槽14の水位が所定の高さより低くなった場合は、ポンプ34が停止され、バルブ44が閉状態とされればよい。
(I) Filtration process The raw water which is to-be-treated water is supplied and stored in the raw water tank 10 through the pipe 52. When the valves 38, 42 are opened, the valves 40, 44, 46, 48, 50 are closed, and the pump 28 is operated, the raw water passes through the pipe 54 into the filtration tower 70 of the long fiber filtration device 12. Supplied from the upper part. Initially, the long fiber bundle 72 that has been almost upright in the water is bent by its own weight and the flow of raw water, and its height is reduced. The raw water flowing in from the upper part of the filtration tower 70 passes downward from the upper part of the filtration tower 70, that is, from the upper end to the lower end of the long fiber bundle 72. Suspended substances etc. in raw water are captured by the part. The clarified treated water flows out from the lower part of the filtration tower 70 and flows into the treated water tank 14 through the pipe 56. When the water level of the treated water tank 14 becomes higher than a predetermined height, the valve 44 is opened and the pump 34 is operated, whereby the treated water is discharged from the treated water tank 14 through the pipe 62. When the water level in the treated water tank 14 becomes lower than a predetermined height, the pump 34 may be stopped and the valve 44 may be closed.

原水の通水中において、長繊維束72は上述のように高さ方向に縮んだ状態となるが、長繊維束72の上方部に比べて下方部がより屈曲している状態となるため、下方部において長繊維束72が密に充填され、その結果、原水中の懸濁物質等は長繊維束72の高さ方向全体の空隙部、表面等に効果的に捕捉される。   In the flow of raw water, the long fiber bundle 72 is contracted in the height direction as described above, but the lower part is bent more than the upper part of the long fiber bundle 72. The long fiber bundle 72 is densely filled in the portion, and as a result, suspended substances and the like in the raw water are effectively captured in the voids, the surface, and the like of the entire long fiber bundle 72 in the height direction.

長繊維束72を構成する長繊維の材質としては、アクリル系、ポリエステル系、ポリプロピレン系、ポリアミド系、ポリアクリルアミド系、ケブラー等の合成繊維;綿、羊毛等の天然繊維などが挙げられ、これらの混合繊維であってもよい。強度が高い等の点から合成繊維が好ましく、加工性が良いとされているポリエステル系合成繊維が好ましい。   Examples of the material of the long fibers constituting the long fiber bundle 72 include synthetic fibers such as acrylic, polyester, polypropylene, polyamide, polyacrylamide, and kevlar; natural fibers such as cotton and wool, and the like. It may be a mixed fiber. Synthetic fibers are preferred from the standpoint of high strength, etc., and polyester-based synthetic fibers that are said to have good processability are preferred.

(ii)逆洗工程
原水の通水を続けていくと、長繊維束72の空隙部等に懸濁物質等が捕捉され、次第にろ過抵抗が増加していく。ろ過抵抗が予め設定された値以上になった場合、あるいは処理水の水質が予め設定された値より悪化した場合には、原水の通水を停止し、長繊維束72に対してろ過方向と逆の方向に水を含む洗浄水等を通過させて堆積した懸濁物質等を除去、洗浄する、いわゆる逆洗を行う。
(Ii) Backwashing process When the raw water is continuously passed, suspended substances and the like are trapped in the voids of the long fiber bundle 72 and the filtration resistance gradually increases. When the filtration resistance is equal to or higher than a preset value, or when the quality of the treated water is worse than the preset value, the flow of the raw water is stopped and the filtration direction with respect to the long fiber bundle 72 is determined. So-called backwashing is performed in which washing water containing water is passed in the opposite direction to remove and wash suspended substances and the like that have accumulated.

例えば、差圧計22により測定される差圧が予め設定された値以上になった等の場合、バルブ38,42,44が閉状態とされ、ポンプ28,34が停止される。バルブ40,46,50が開状態とされ、ブロワ20、ポンプ30が運転されることにより、ろ過塔70の下方部より、配管68を通して供給される空気等の気体とともに、水を含む洗浄水として処理水槽14中の処理水が配管64を通して供給され、長繊維束72に対してろ過方向と逆の方向に気体および洗浄水が通過して堆積した懸濁物質等が除去、洗浄される(第一逆洗工程)。洗浄水はろ過塔70の上方部から流出され、逆洗排水として、配管58を通して逆洗排水槽16に流入される。この場合、ポンプ30が逆洗水導入手段として機能する。洗浄水として原水がろ過塔70の下方部より供給(図示せず)されてもよい。この場合、ポンプ28が逆洗水導入手段として機能する。   For example, when the differential pressure measured by the differential pressure gauge 22 exceeds a preset value, the valves 38, 42, 44 are closed, and the pumps 28, 34 are stopped. When the valves 40, 46, and 50 are opened and the blower 20 and the pump 30 are operated, the cleaning water containing water is contained together with a gas such as air supplied from the lower part of the filtration tower 70 through the pipe 68. The treated water in the treated water tank 14 is supplied through the pipe 64, and the suspended substances and the like accumulated by passing the gas and the washing water in the direction opposite to the filtration direction with respect to the long fiber bundle 72 are removed and washed (first). One backwash process). The washing water flows out from the upper part of the filtration tower 70 and flows into the backwash drain 16 through the pipe 58 as backwash drainage. In this case, the pump 30 functions as backwash water introduction means. Raw water may be supplied (not shown) from the lower part of the filtration tower 70 as the washing water. In this case, the pump 28 functions as backwash water introduction means.

第一逆洗工程が予め設定された時間(この第一逆洗工程における洗浄水による洗浄時間を「第一洗浄時間」と呼ぶ)行われた後、バルブ48が開状態とされ、ポンプ36が運転されることにより、殺菌剤貯槽18から殺菌剤が配管66を通して配管64の処理水に供給されて水および殺菌剤を含む殺菌剤含有水がろ過塔70の下方部より配管64を通して、配管68を通して供給される空気等の気体とともに供給され、長繊維束72に対してろ過方向と逆の方向に気体および殺菌剤含有水が通過して殺菌処理される(第二逆洗工程)。図示しない洗浄制御手段により、洗浄水による第一逆洗工程の後に、殺菌剤含有水による第二逆洗工程が行われるように制御される。殺菌剤含有水はろ過塔70の上方部から流出され、逆洗排水として、配管58を通して逆洗排水槽16に流入される。この場合、ポンプ30およびポンプ36が殺菌剤含有水導入手段として機能する。洗浄水として原水がろ過塔70の下方部より供給される場合には、ポンプ28およびポンプ36が殺菌剤含有水導入手段として機能する。   After the first back washing step is performed for a preset time (the washing time with the washing water in the first back washing step is referred to as “first washing time”), the valve 48 is opened and the pump 36 is turned on. By being operated, the bactericide is supplied from the bactericide storage tank 18 to the treated water in the pipe 64 through the pipe 66, and the bactericide-containing water containing water and the bactericide is passed from the lower part of the filtration tower 70 through the pipe 64 through the pipe 68. The gas and the bactericidal agent-containing water are supplied to the long fiber bundle 72 in the direction opposite to the filtration direction and sterilized (second backwashing step). By a cleaning control means (not shown), control is performed so that the second backwashing step with the bactericide-containing water is performed after the first backwashing step with the washing water. The disinfectant-containing water flows out from the upper part of the filter tower 70 and flows into the backwash drain 16 through the pipe 58 as backwash drainage. In this case, the pump 30 and the pump 36 function as a disinfectant-containing water introduction unit. When raw water is supplied from the lower part of the filtration tower 70 as the washing water, the pump 28 and the pump 36 function as a sterilizing agent-containing water introducing unit.

第二逆洗工程において、殺菌剤濃度測定装置24により測定される配管58における逆洗排水中の残留殺菌剤の濃度が予め設定された範囲内(この第二逆洗工程における逆洗排水中の残留殺菌剤濃度の設定範囲を「第一設定範囲」と呼ぶ)になるように、図示しない殺菌剤添加量制御手段等によってポンプ36の流量等が調整されることにより、殺菌剤の添加量が制御される。   In the second backwashing step, the concentration of the residual disinfectant in the backwash drainage in the pipe 58 measured by the disinfectant concentration measuring device 24 is within a preset range (in the backwash wastewater in the second backwash step). The flow rate of the pump 36 is adjusted by a bactericide addition amount control means (not shown) so that the set range of the residual bactericide concentration is referred to as a “first set range”. Be controlled.

逆洗排水槽16の水位が所定の高さより高くなった場合は、ポンプ32が運転されることにより、逆洗排水は逆洗排水槽16から配管60を通して排出される。逆洗排水槽16の水位が所定の高さより低くなった場合は、ポンプ32が停止されればよい。   When the water level of the backwash drain 16 becomes higher than a predetermined height, the backwash wastewater is discharged from the backwash drain 16 through the pipe 60 by operating the pump 32. When the water level of the backwash drain 16 becomes lower than a predetermined height, the pump 32 may be stopped.

第二逆洗工程が予め設定された時間(この第二逆洗工程における殺菌剤含有水による洗浄時間を「第二洗浄時間」と呼ぶ)行われた後、バルブ40,46,48,50が閉状態とされ、ポンプ30,36、ブロワ20が停止される。   After the second back washing step is performed for a preset time (the washing time with the bactericide-containing water in the second back washing step is referred to as “second washing time”), the valves 40, 46, 48, 50 are The closed state is established, and the pumps 30 and 36 and the blower 20 are stopped.

第二逆洗工程が終了したら、必要に応じて、ろ過工程に戻ればよい。   What is necessary is just to return to a filtration process as needed, if a 2nd backwashing process is complete | finished.

本実施形態では、長繊維ろ材に捕捉された懸濁物質等の大部分を洗浄水による逆洗(第一逆洗工程)により排出した後から逆洗水への殺菌剤の添加を開始する。長繊維ろ材に捕捉された懸濁物質等は、通常の洗浄水による逆洗による物理的な洗浄で大部分が除去されるため、それらを洗浄水による逆洗により排出した後から逆洗水への殺菌剤の添加を開始することで、殺菌剤の添加量を大幅に削減でき、効率よく長繊維ろ材の殺菌を行うことができる。   In this embodiment, the addition of the bactericide to the backwashing water is started after most of the suspended substances and the like trapped in the long fiber filter medium are discharged by backwashing with the washing water (first backwashing process). Most of the suspended substances trapped in the long fiber filter medium are removed by physical washing by backwashing with normal washing water, so after they are discharged by backwashing with washing water, they are returned to backwashing water. By starting the addition of the bactericidal agent, the amount of the bactericidal agent added can be greatly reduced, and the long fiber filter medium can be sterilized efficiently.

本実施形態において、第一逆洗工程における洗浄時間(第一洗浄時間)は、第一逆洗工程における洗浄時間(第一洗浄時間)および第二逆洗工程における洗浄時間(第二洗浄時間)を合わせた全洗浄時間の10〜30%の範囲であることが好ましい。逆洗工程で使用する逆洗水の水量は、通常、ろ過層体積(本実施形態においては、充填された長繊維ろ材の長さ×ろ過面積)の8倍〜10倍量程度であり、逆洗水の線速度(LV)は、45〜100m/h程度である。そして、後述する図3に示すように、第一逆洗工程において逆洗水全使用量の10〜30vol%を使用した時点で長繊維ろ材に捕捉された懸濁物質等の5〜8割が除去される。通常、逆洗水量の設定は逆洗工程中に変えないため、第一洗浄時間が、全洗浄時間の10〜30%の範囲であれば、長繊維ろ材に捕捉された懸濁物質等の5〜8割が除去されるので、そのタイミングで殺菌剤を添加して第二逆洗工程を行うのがよい。洗浄時間の制御は、図示しない洗浄制御手段により行われる。   In this embodiment, the cleaning time in the first backwashing process (first cleaning time) is the cleaning time in the first backwashing process (first cleaning time) and the cleaning time in the second backwashing process (second cleaning time). Is preferably in the range of 10 to 30% of the total washing time. The amount of backwash water used in the backwashing process is usually about 8 to 10 times the volume of the filtration layer (in this embodiment, the length of the long fiber filter medium filled × the filtration area), and the reverse The linear velocity (LV) of the washing water is about 45 to 100 m / h. And as shown in FIG. 3 mentioned later, 50 to 80% of the suspended substances etc. trapped by the long fiber filter medium at the time of using 10 to 30 vol% of the total amount of backwashing water used in the first backwashing step. Removed. Usually, the setting of the amount of backwashing water is not changed during the backwashing process, so if the first washing time is in the range of 10 to 30% of the total washing time, the suspended matter trapped in the long fiber filter medium, etc. Since ~ 80% is removed, it is better to add a bactericidal agent at that timing and perform the second backwashing step. The cleaning time is controlled by a cleaning control means (not shown).

殺菌剤としては、特に制限はないが、殺菌性等の点から、通常、塩素系殺菌剤が用いられる。塩素系殺菌剤としては、例えば、次亜塩素酸ナトリウム、液体塩素、さらし粉、クロラミンT等が挙げられ、殺菌性、汎用性等の点から次亜塩素酸ナトリウムが好ましい。   Although there is no restriction | limiting in particular as a bactericidal agent, From points, such as bactericidal property, a chlorine-type bactericidal agent is used normally. Examples of the chlorine-based disinfectant include sodium hypochlorite, liquid chlorine, bleached powder, chloramine T, and the like, and sodium hypochlorite is preferable from the viewpoint of bactericidal properties and versatility.

殺菌剤として塩素系殺菌剤を用いる場合、第二逆洗工程における配管58の逆洗排水中の残留塩素濃度(第一設定範囲)が0.5〜10mg/Lの範囲になるように塩素系殺菌剤の添加量を制御することが好ましく、1.5〜5mg/Lの範囲になるように塩素系殺菌剤の添加量を制御することがより好ましい。第二逆洗工程における逆洗排水中の残留塩素濃度が0.5mg/L未満では、長繊維ろ材の殺菌が十分行われない可能性があり、10mg/Lを超えると、逆洗排水の排水先に影響を及ぼす可能性がある。   When using a chlorine-based disinfectant as the disinfectant, the chlorine-based concentration is such that the residual chlorine concentration (first set range) in the backwash drainage of the pipe 58 in the second backwash step is in the range of 0.5 to 10 mg / L. It is preferable to control the addition amount of the bactericidal agent, and it is more preferable to control the addition amount of the chlorine-based bactericidal agent so as to be in the range of 1.5 to 5 mg / L. If the residual chlorine concentration in the backwash wastewater in the second backwash process is less than 0.5 mg / L, the long fiber filter medium may not be sufficiently sterilized. If it exceeds 10 mg / L, the backwash wastewater drainage. There is a possibility of affecting the future.

ろ過塔70の上方部と支持体74下方部との間の差圧の設定値としては、1〜1.5mAq(0.1〜0.15kgf/cmまたは9.8〜14.7×10−3MPa)の範囲であることが好ましい。差圧は、図1に示すように、差圧計22を設けることにより、測定することができる。その他には、ろ過塔70への原水流入のための配管54および処理水流出のための配管56に圧力測定装置として圧力計を取り付けて制御部で差分を読み取る方法や、ろ過塔70として重力型ろ過池を用いた場合には長繊維束72の上部から1〜1.5m程度の付近にレベルスイッチを取り付けてろ過抵抗を読み取る(重力型ではろ過抵抗が高くなるとろ過池内の水位が高くなる)方法等が挙げられる。 The set value of the differential pressure between the upper part of the filtration tower 70 and the lower part of the support 74 is 1 to 1.5 mAq (0.1 to 0.15 kgf / cm 2 or 9.8 to 14.7 × 10. −3 MPa). The differential pressure can be measured by providing a differential pressure gauge 22 as shown in FIG. In addition, a pressure gauge is attached as a pressure measuring device to the piping 54 for inflow of raw water to the filtration tower 70 and the piping 56 for outflow of treated water, and the difference is read by the control unit. When a filtration pond is used, a level switch is attached in the vicinity of about 1 to 1.5 m from the upper part of the long fiber bundle 72 and the filtration resistance is read (in the gravity type, when the filtration resistance increases, the water level in the filtration pond increases) Methods and the like.

本実施形態において、第二逆洗工程の後に、長繊維束72と殺菌剤とを所定の時間接触させる以下の浸漬工程を行うことが好ましい。第二逆洗工程終了後にすぐにろ過工程に戻らずに、長繊維ろ材と殺菌剤との接触時間を長くし、殺菌効果を高める浸漬工程を設けると洗浄、殺菌がさらに効果的になる。   In the present embodiment, it is preferable to perform the following dipping process in which the long fiber bundle 72 and the bactericide are brought into contact with each other for a predetermined time after the second back washing process. Washing and sterilization become more effective by providing a dipping step that increases the contact time between the long fiber filter medium and the bactericidal agent and increases the bactericidal effect without returning to the filtration step immediately after the end of the second backwashing step.

(iii)浸漬工程
例えば、ろ過継続時間が予め設定した値の30%以上減少した場合に浸漬工程が行われる。第二逆洗工程が予め設定された時間(第二洗浄時間)行われた後、ポンプ30が停止され、バルブ40,46が閉状態とされ、ブロワ20により空気撹拌されながら殺菌剤濃度測定装置24により測定される逆洗排水中の残留殺菌剤の濃度が予め設定された範囲内(この浸漬工程における逆洗排水中の残留殺菌剤濃度の設定範囲を「第二設定範囲」と呼ぶ)になるように、図示しない殺菌剤添加量制御手段によってポンプ36の流量等が調整されることにより、殺菌剤の添加量が制御される。殺菌剤濃度測定装置24により測定される逆洗排水中の残留殺菌剤の濃度が第二設定範囲内に到達したら、バルブ48が閉状態とされ、ポンプ36が停止され、予め設定された浸漬時間の間、ブロワ20により空気撹拌されながら長繊維束72が殺菌剤含有水に浸漬され、殺菌剤に接触される。この場合、ろ過塔70が浸漬手段として機能する。予め設定された浸漬時間が経過したら、バルブ50が閉状態とされ、ブロワ20が停止される。
(Iii) Immersion step For example, the immersion step is performed when the filtration duration time is reduced by 30% or more of a preset value. After the second back washing process is performed for a preset time (second washing time), the pump 30 is stopped, the valves 40 and 46 are closed, and the bactericide is measured by the blower 20 while being stirred by air. The concentration of the residual disinfectant in the backwash wastewater measured by 24 is within a preset range (the set range of the residual disinfectant concentration in the backwash wastewater in this dipping process is referred to as “second set range”). As described above, the addition amount of the bactericide is controlled by adjusting the flow rate of the pump 36 by a bactericide addition amount control means (not shown). When the concentration of the residual sterilizing agent in the backwash waste water measured by the sterilizing agent concentration measuring device 24 reaches the second setting range, the valve 48 is closed, the pump 36 is stopped, and the preset immersion time is set. Meanwhile, the long fiber bundle 72 is immersed in the sterilizing agent-containing water while being agitated by the blower 20 and is brought into contact with the sterilizing agent. In this case, the filtration tower 70 functions as an immersion means. When the preset immersion time has elapsed, the valve 50 is closed and the blower 20 is stopped.

浸漬工程が終了したら、必要に応じて、ろ過工程に戻ればよい。   When the dipping process is completed, the process may be returned to the filtration process as necessary.

殺菌剤として塩素系殺菌剤を用いる場合、浸漬工程における配管58の逆洗排水中の残留塩素濃度(第二設定範囲)が1.5〜15mg/Lの範囲になるように塩素系殺菌剤の添加量を制御することが好ましい。浸漬工程における逆洗排水中の残留塩素濃度が1.5mg/L未満では、長繊維ろ材の殺菌が十分行われない可能性があり、15mg/Lを超えると、逆洗排水の排水先に影響を及ぼす可能性がある。   When using a chlorine-based disinfectant as the disinfectant, the chlorine-based disinfectant is adjusted so that the residual chlorine concentration (second set range) in the backwash drainage of the pipe 58 in the dipping process is in the range of 1.5 to 15 mg / L. It is preferable to control the addition amount. If the residual chlorine concentration in the backwash wastewater in the dipping process is less than 1.5 mg / L, the long fiber filter medium may not be sufficiently sterilized. If it exceeds 15 mg / L, the backwash wastewater destination is affected. May affect.

浸漬工程における浸漬時間は、15分から60分の範囲が好ましい。15分より短いと長繊維ろ材との接触時間が短いため効果が低くなる場合があり、60分を超えると逆洗時間が長くなり、一日に処理できる水量が減少する場合がある。   The immersion time in the immersion process is preferably in the range of 15 minutes to 60 minutes. If the time is shorter than 15 minutes, the effect may be reduced because the contact time with the long fiber filter medium is short. If the time is longer than 60 minutes, the backwash time becomes longer, and the amount of water that can be treated per day may be reduced.

本実施形態に係る長繊維ろ過装置は、上水道水、下水処理水、河川水、湖沼水、凝集沈殿上澄み水、各種工程中間水、各種回収水、各種廃水等の原水中の懸濁物質等を除去するために用いることができ、特に、生物処理による下水処理水等の生物処理水中の懸濁物質等を除去するために好適に用いることができる。   The long fiber filtration device according to the present embodiment is provided with suspended substances in raw water such as tap water, sewage treated water, river water, lake water, coagulation sediment supernatant water, various process intermediate water, various recovered water, various waste water, etc. It can be used for removing, and in particular, it can be suitably used for removing suspended substances in biologically treated water such as sewage treated water by biological treatment.

図2は、本実施形態に係るろ過システムを生物処理装置で処理した生物処理水の処理に用いる場合の水処理システムの一例を示す概略図である。   FIG. 2 is a schematic diagram illustrating an example of a water treatment system when the filtration system according to the present embodiment is used for treatment of biologically treated water treated by a biological treatment apparatus.

水処理システム3は、ろ過システム1の前段側に生物処理装置5を備える。生物処理装置5は、沈砂池78と、最初沈殿池80と、生物処理を行う生物処理槽82と、生物処理槽で処理した水を固液分離する固液分離装置として最終沈殿池84とを備える。   The water treatment system 3 includes a biological treatment device 5 on the front side of the filtration system 1. The biological treatment apparatus 5 includes a sand basin 78, an initial sedimentation basin 80, a biological treatment tank 82 that performs biological treatment, and a final sedimentation basin 84 as a solid-liquid separation device that separates water treated in the biological treatment tank. Prepare.

生物処理装置5において、下水等の被処理水は、沈砂池78において土砂等が沈殿により分離され、最初沈殿池80において沈砂池78で除去されなかった浮遊物等が沈殿により分離された後、生物処理槽82において活性汚泥により生物処理が行われて汚れが分解され(生物処理工程)、最終沈殿池84において活性汚泥が沈殿により分離される(固液分離工程)。得られた生物処理水は、被処理水としてろ過システム1に送られ、長繊維ろ材によるろ過処理が行われる。ろ過システム1においてろ過処理が行われた処理水は、滅菌池76において消毒された後、河川や海等に放流される。   In the biological treatment apparatus 5, the treated water such as sewage is separated from sediment by sedimentation in the sedimentation basin 78, and suspended matter that has not been removed by the sedimentation basin 78 in the first sedimentation basin 80 is separated by sedimentation. Biological treatment is performed with activated sludge in the biological treatment tank 82 to decompose the dirt (biological treatment step), and the activated sludge is separated by precipitation in the final sedimentation tank 84 (solid-liquid separation step). The obtained biologically treated water is sent to the filtration system 1 as water to be treated, and is subjected to filtration using a long fiber filter medium. The treated water that has been filtered in the filtration system 1 is sterilized in the sterilization pond 76 and then discharged into a river or the sea.

本実施形態に係る水処理システム3において、長繊維ろ過装置12で発生する逆洗排水を生物処理槽82で行われる生物処理工程および生物処理槽82、すなわち生物処理工程の上流側の少なくとも1つに返送する返送工程を含んでもよい。図2の例では、生物処理槽82の上流側である沈砂池78に逆洗排水が返送されているが、最初沈殿池80に返送されてもよいし、生物処理槽82に返送されてもよい。これらの場合、ポンプ32が返送手段として機能する。   In the water treatment system 3 according to the present embodiment, at least one of the biological treatment process in which the backwash wastewater generated in the long fiber filtration device 12 is performed in the biological treatment tank 82 and the biological treatment tank 82, that is, the upstream side of the biological treatment process. A return process for returning to the server may be included. In the example of FIG. 2, the backwash wastewater is returned to the sand basin 78 on the upstream side of the biological treatment tank 82, but may be first returned to the sedimentation tank 80 or returned to the biological treatment tank 82. Good. In these cases, the pump 32 functions as a return means.

本実施形態では、逆洗排水槽16内の逆洗排水の残留殺菌剤濃度を低濃度に維持することができるため、逆洗排水を生物処理に戻すことができる。また、殺菌剤の添加量を削減することができるため、生物処理に戻す逆洗排水の殺菌剤の濃度が低くなり、生物処理が安定する。   In this embodiment, since the residual disinfectant concentration of the backwash wastewater in the backwash wastewater tank 16 can be maintained at a low concentration, the backwash wastewater can be returned to the biological treatment. Moreover, since the addition amount of a bactericidal agent can be reduced, the density | concentration of the bactericide of the backwash waste water returned to a biological treatment becomes low, and a biological treatment is stabilized.

以下、実施例および比較例を挙げ、本発明をより具体的に詳細に説明するが、本発明は、以下の実施例に限定されるものではない。   Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

図1に示すろ過システムを用いて、ろ過実験を行った。原水槽(800L)に下水二次処理水を溜め、ろ過速度1,000m/dayにて、ろ過層が1mになるように長繊維ろ材を充填したろ過塔(φ280mm×2,000mm)に通水した。ろ過抵抗が1,000mmに達したら、ろ材が捕捉した懸濁物質等を逆洗によって排出した。逆洗水の流量はLV 100m/h、逆洗空気の流量はLV 400m/hで固定し、空気および水逆洗を4分間行った後に、水逆洗を2分間行った。逆洗中は残留塩素計にて残留塩素濃度を測定し、所定の濃度になるように次亜塩素酸ナトリウム注入ポンプの吐出量をコントロールした。逆洗工程で使用した逆洗水の水量は、ろ過層体積(充填した長繊維ろ材の長さ1m×ろ過面積0.0615m)の10倍程度であった。 A filtration experiment was conducted using the filtration system shown in FIG. Sewage secondary treated water is stored in the raw water tank (800L), and water is passed through a filtration tower (φ280 mm × 2,000 mm) filled with long fiber filter media so that the filtration layer becomes 1 m at a filtration speed of 1,000 m / day. did. When the filtration resistance reached 1,000 mm, suspended substances captured by the filter medium were discharged by backwashing. The flow rate of backwash water was fixed at LV 100 m / h, the flow rate of backwash air was fixed at LV 400 m / h, air and water backwashing was performed for 4 minutes, and then water backwashing was performed for 2 minutes. During backwashing, the residual chlorine concentration was measured with a residual chlorine meter, and the discharge amount of the sodium hypochlorite injection pump was controlled so as to obtain a predetermined concentration. The amount of backwash water used in the backwashing process was about 10 times the filtration layer volume (length of filled long fiber filter medium 1 m × filtration area 0.0615 m 2 ).

<実施例1〜3、比較例1>
一般的な下水処理水を原水として用い、二ヶ月間通水した。水質はSS:1.5mg/L、BOD:5mg/L、T−N:6mg/L、NO−N:5mg/L、NH−N:1mg/Lであった。24時間連続通水するか、ろ過抵抗1,000mmに達したら逆洗を行った。
<Examples 1-3, Comparative Example 1>
General sewage treated water was used as raw water and passed for two months. Water quality SS: 1.5mg / L, BOD: 5mg / L, T-N: 6mg / L, NO 3 -N: 5mg / L, NH 4 -N: was 1 mg / L. Water was continuously passed for 24 hours, or backwashing was performed when the filtration resistance reached 1,000 mm.

表1に逆洗条件および実験結果を示す。比較例1は逆洗開始直後から、逆洗排水ライン中の残留塩素が1.5mg/Lになるように殺菌剤として次亜塩素酸ナトリウムを添加した条件である。実施例1では、全洗浄時間の30%経過後(ろ過層体積の三倍量程度の逆洗水および逆洗空気で洗浄した後)から、殺菌剤として次亜塩素酸ナトリウムを逆洗排水ライン中の残留塩素として1.5mg/Lになるように添加した。実施例1を基本条件とし、残留塩素として0.5mg/Lになるように添加した条件が実施例2であり、次亜塩素酸ナトリウムを全洗浄時間の10%経過後(ろ過層体積の一倍量程度の逆洗水および逆洗空気で洗浄した後)に添加した条件が実施例3である。   Table 1 shows backwash conditions and experimental results. Comparative Example 1 is a condition in which sodium hypochlorite was added as a disinfectant so that the residual chlorine in the backwash drainage line was 1.5 mg / L immediately after the start of backwashing. In Example 1, after 30% of the total washing time has elapsed (after washing with backwashing water and backwashing air about three times the volume of the filtration layer), sodium hypochlorite is used as a disinfectant in the backwash drainage line. The residual chlorine was added to 1.5 mg / L. Example 2 is based on the basic conditions of Example 1 and the amount of residual chlorine added to be 0.5 mg / L is Example 2. Sodium hypochlorite was added after 10% of the total washing time (one part of the filtration layer volume). The condition added after washing with about twice the amount of backwash water and backwash air is Example 3.

Figure 0005714419
Figure 0005714419

[結果]
比較例1では、二ヵ月後のろ過抵抗は通水初期とほぼ変わらなかったが、次亜塩素酸ナトリウム添加量および逆洗排水槽内の残留塩素濃度が高かった。これに対して、実施例1では、二ヵ月後のろ過抵抗は比較例1と同等であり、次亜塩素酸ナトリウム添加量および逆洗排水槽内の残留塩素濃度が比較例1よりも大幅に減った。実施例2では、次亜塩素酸ナトリウム添加量および逆洗排水槽内の残留塩素濃度は非常に低かったが、二ヵ月後のろ過抵抗が上昇した。実施例3では、二ヵ月後のろ過抵抗は比較例1と同等であり、次亜塩素酸ナトリウム添加量および残留塩素濃度は比較例1よりやや低かった。
[result]
In Comparative Example 1, the filtration resistance after 2 months was almost the same as the initial stage of water flow, but the amount of sodium hypochlorite added and the residual chlorine concentration in the backwash drain were high. On the other hand, in Example 1, the filtration resistance after two months was equivalent to that in Comparative Example 1, and the amount of sodium hypochlorite added and the residual chlorine concentration in the backwash drain were significantly greater than in Comparative Example 1. decreased. In Example 2, although the amount of sodium hypochlorite added and the residual chlorine concentration in the backwash drain were very low, the filtration resistance after two months increased. In Example 3, the filtration resistance after 2 months was equivalent to that of Comparative Example 1, and the amount of sodium hypochlorite added and the residual chlorine concentration were slightly lower than those of Comparative Example 1.

実施例2および実施例3は、全洗浄時間の30%経過後(ろ過層体積の三倍量程度の逆洗水および逆洗空気で洗浄した後)から次亜塩素酸ナトリウムを添加したことで次亜塩素酸ナトリウムの使用量が減少した。また、次亜塩素酸ナトリウム添加前に排出されたSSにより残留塩素が消費されるため、逆洗排水槽内の残留塩素濃度が大幅に減少した。実施例3では全洗浄時間の10%経過後(ろ過層体積の一倍量程度の逆洗水および逆洗空気で逆洗した後)から次亜塩素酸ナトリウムの添加を開始したため、次亜塩素酸ナトリウムの使用量および逆洗排水槽内の残留塩素濃度は大幅には下がらなかった。実施例2では残留塩素濃度0.5mg/Lで添加量を制御したため、通水二ヵ月後にはろ過抵抗が上昇した。   In Example 2 and Example 3, sodium hypochlorite was added after 30% of the total washing time had elapsed (after washing with backwashing water and backwashing air about three times the volume of the filtration layer). The amount of sodium hypochlorite used has decreased. Moreover, since residual chlorine was consumed by SS discharged | emitted before sodium hypochlorite addition, the residual chlorine density | concentration in a backwash drainage tank reduced significantly. In Example 3, since the addition of sodium hypochlorite was started after 10% of the total washing time had elapsed (after backwashing with backwashing water and backwashing air of about one volume of the filtration layer volume), hypochlorous acid was added. The amount of sodium acid used and the residual chlorine concentration in the backwash drain were not significantly reduced. In Example 2, since the amount of addition was controlled at a residual chlorine concentration of 0.5 mg / L, the filtration resistance increased two months after the water flow.

図3に全逆洗時間に対する経過時間(%)と逆洗排水SS(mg/L)との関係を示す。図3のグラフの面積は、逆洗により排出されるSS量に比例している。全逆洗時間に対して30%の時間が経過すると、捕捉したSSの大部分(80%程度)が排出されることがわかる。また、全逆洗時間に対して10%の時間が経過すると、捕捉したSSの50%程度が排出されることがわかる。   FIG. 3 shows the relationship between the elapsed time (%) with respect to the total backwash time and the backwash drainage SS (mg / L). The area of the graph in FIG. 3 is proportional to the amount of SS discharged by backwashing. It can be seen that when 30% of the total backwash time has elapsed, most of the captured SS (about 80%) is discharged. Further, it can be seen that when 10% of the total backwash time has elapsed, about 50% of the captured SS is discharged.

<実施例4,5、比較例2>
ろ過抵抗が上がりやすいとされている下水処理水を原水として二ヶ月間通水した。水質はSS:3.5mg/L、BOD:22mg/L、T−N:24mg/L、NO−N:2mg/L、NH−N:22mg/Lであった。48時間連続通水を行うか、ろ過抵抗が1,000mmに達したら逆洗を行った。
<Examples 4 and 5 and Comparative Example 2>
Sewage treated water, which is thought to increase filtration resistance, was passed for 2 months as raw water. The water quality was SS: 3.5 mg / L, BOD: 22 mg / L, TN: 24 mg / L, NO 3 -N: 2 mg / L, NH 4 -N: 22 mg / L. Water was passed continuously for 48 hours, or backwashing was performed when the filtration resistance reached 1,000 mm.

表2に逆洗条件および結果を示す。実験は、比較例1と同様の条件とした比較例2、実施例1と同様の条件とした実施例4、実施例4を基本条件とし、一週間に一回、浸漬工程として残留塩素濃度が2mg/L程度になるように次亜塩素酸ナトリウムを追加注入し、空気撹拌しながら30分間浸漬する実施例5を行った。   Table 2 shows the backwash conditions and results. The experiment is based on the same conditions as in Comparative Example 2 and Comparative Example 2 and in Example 4 and Example 4 as in Example 1, with the residual chlorine concentration as a dipping process once a week. Example 5 was performed, in which sodium hypochlorite was additionally injected so as to be about 2 mg / L, and immersed for 30 minutes while stirring with air.

Figure 0005714419
Figure 0005714419

[結果]
比較例2では、逆洗開始直後から次亜塩素酸ナトリウムを添加したため、次亜塩素酸ナトリウム使用量が多かった。実施例4および実施例5では、比較例2と比べて、次亜塩素酸ナトリウム使用量が大幅に減った。比較例2および実施例4では、浸漬工程が無いため、二ヵ月後のろ過継続時間が減少した。実施例5では、浸漬工程を設けたため、二ヵ月後のろ過継続時間はそれほど減少しなかった。また、実施例5では、浸漬工程で次亜塩素酸ナトリウムを追加注入したので、実施例4に比べて次亜塩素酸ナトリウム使用量がわずかに増えた。
[result]
In Comparative Example 2, since sodium hypochlorite was added immediately after the start of backwashing, the amount of sodium hypochlorite used was large. In Example 4 and Example 5, the amount of sodium hypochlorite used was significantly reduced as compared with Comparative Example 2. In Comparative Example 2 and Example 4, since there was no immersion step, the filtration duration after two months decreased. In Example 5, since the immersion process was provided, the filtration continuation time after two months did not decrease so much. Moreover, in Example 5, since sodium hypochlorite was additionally injected in the dipping process, the amount of sodium hypochlorite used was slightly increased compared to Example 4.

1 ろ過システム、3 水処理システム、5 生物処理装置、10 原水槽、12 長繊維ろ過装置、14 処理水槽、16 逆洗排水槽、18 殺菌剤貯槽、20 ブロワ、22 差圧計、24,26 殺菌剤濃度測定装置、28,30,32,34,36 ポンプ、38,40,42,44,46,48,50 バルブ、52,54,56,58,60,62,64,66,68 配管、70 ろ過塔、72 長繊維束、74 支持体、76 滅菌池、78 沈砂池、80 最初沈殿池、82 生物処理槽、84 最終沈殿池。   DESCRIPTION OF SYMBOLS 1 Filtration system, 3 Water treatment system, 5 Biological treatment device, 10 Raw water tank, 12 Long fiber filtration device, 14 Treatment water tank, 16 Backwash drainage tank, 18 Disinfectant storage tank, 20 Blower, 22 Differential pressure gauge, 24, 26 Sterilization Agent concentration measuring device, 28, 30, 32, 34, 36 pump, 38, 40, 42, 44, 46, 48, 50 valve, 52, 54, 56, 58, 60, 62, 64, 66, 68 piping, 70 Filtration tower, 72 long fiber bundle, 74 support, 76 sterilization pond, 78 sand basin, 80 first sedimentation basin, 82 biological treatment tank, 84 final sedimentation basin.

Claims (6)

ろ過塔と、前記ろ過塔内部に設けられた支持体と、前記支持体に下端を固定されるとともに、その上端を自由端とした長繊維束とを有する、長繊維束により被処理水中の懸濁物質を捕捉する長繊維ろ過装置の逆洗方法であって、
前記長繊維ろ過装置により処理する被処理水が、生物処理を行う生物処理工程と、前記生物処理工程で処理した水を固液分離する固液分離工程とを少なくとも含む生物処理で処理した生物処理水であり、
前記長繊維ろ過装置でろ過された水により逆洗を行う第一逆洗工程と、
前記第一逆洗工程の後に、前記長繊維ろ過装置でろ過された水および塩素系殺菌剤を含む殺菌剤含有水により逆洗を行う第二逆洗工程と、
前記第一逆洗工程で前記ろ過塔から流出された逆洗排水および前記第二逆洗工程で前記ろ過塔から流出された逆洗排水を逆洗排水槽に貯留した後、前記逆洗排水槽に貯留した水を前記生物処理工程および前記生物処理工程の上流側の少なくとも1つに返送する返送工程と、
を含み、
前記第二逆洗工程における逆洗排水中の残留塩素濃度が1.5〜10mg/Lの範囲になるように前記塩素系殺菌剤を添加することを特徴とする長繊維ろ過装置の逆洗方法。
A suspension in the water to be treated by a long fiber bundle, which includes a filtration tower, a support provided inside the filtration tower, and a long fiber bundle having a lower end fixed to the support and having an upper end as a free end. A backwashing method for a long fiber filtration device for capturing turbid substances,
The biological treatment in which the water to be treated to be treated by the long fiber filtration device is treated by biological treatment including at least a biological treatment step for biological treatment and a solid-liquid separation step for solid-liquid separation of the water treated in the biological treatment step. Water
A first backwashing step of backwashing with water filtered by the long fiber filtration device ;
After the first backwashing step, a second backwashing step of performing backwashing with water filtered with the long fiber filtration device and a bactericide-containing water containing a chlorine-based bactericide;
The backwash drainage tank after storing the backwash drainage discharged from the filtration tower in the first backwashing process and the backwash drainage discharged from the filtration tower in the second backwashing process in the backwash drainage tank A return step of returning the stored water to at least one of the biological treatment step and the upstream side of the biological treatment step;
Only including,
The backwashing method for a long fiber filtration device , wherein the chlorine-based disinfectant is added so that the residual chlorine concentration in the backwashing waste water in the second backwashing step is in the range of 1.5 to 10 mg / L. .
請求項1に記載の長繊維ろ過装置の逆洗方法であって、
前記第一逆洗工程における洗浄時間が、前記第一逆洗工程における洗浄時間および前記第二逆洗工程における洗浄時間を合わせた全洗浄時間の10〜30%の範囲であることを特徴とする長繊維ろ過装置の逆洗方法。
It is a backwashing method of the long fiber filtration device according to claim 1,
The cleaning time in the first backwashing step is in the range of 10 to 30% of the total cleaning time including the cleaning time in the first backwashing step and the cleaning time in the second backwashing step. Backwash method for long fiber filtration equipment.
請求項1または2に記載のろ過装置の逆洗方法であって、
前記第二逆洗工程の後に、前記長繊維束と殺菌剤とを所定の時間接触させる浸漬工程を含むことを特徴とする長繊維ろ過装置の逆洗方法。
A backwashing method for a filtration device according to claim 1 or 2 ,
A backwashing method for a long fiber filtration device, comprising a dipping step in which the long fiber bundle and the disinfectant are brought into contact with each other for a predetermined time after the second backwashing step.
ろ過塔と、前記ろ過塔内部に設けられた支持体と、前記支持体に下端を固定されるとともに、その上端を自由端とした長繊維束とを有する、長繊維束により被処理水中の懸濁物質を捕捉する長繊維ろ過装置の逆洗装置であって、
前記長繊維ろ過装置により処理する被処理水が、生物処理を行う生物処理槽と、前記生物処理槽で処理した水を固液分離する固液分離装置とを少なくとも有する生物処理装置で処理した生物処理水であり、
前記ろ過塔内部に前記長繊維ろ過装置でろ過された水を導入して前記ろ過塔を逆洗する逆洗水導入手段と、
前記ろ過塔内部に前記長繊維ろ過装置でろ過された水および塩素系殺菌剤を含む殺菌剤含有水を導入して前記ろ過塔を殺菌逆洗する殺菌剤含有水導入手段と、
前記殺菌剤含有水による洗浄により発生する逆洗排水中の残留塩素濃度が1.5〜10mg/Lの範囲になるように前記殺菌剤の添加量を制御する殺菌剤添加量制御手段と、
記逆洗を行った後に、前記殺菌逆洗を行うように制御する洗浄制御手段と、
前記逆洗により前記ろ過塔から流出された逆洗排水および前記殺菌逆洗により前記ろ過塔から流出された殺菌逆洗排水を逆洗排水槽に貯留した後、前記逆洗排水槽に貯留した水を前記生物処理槽および前記生物処理槽の上流側の少なくとも1つに返送する返送手段と、
を有することを特徴とする長繊維ろ過装置の逆洗装置。
A suspension in the water to be treated by a long fiber bundle, which includes a filtration tower, a support provided inside the filtration tower, and a long fiber bundle having a lower end fixed to the support and having an upper end as a free end. A backwash device for a long fiber filtration device that captures turbid substances,
The treated water to be treated by the long fiber filtration device is a living organism treated by a biological treatment device having at least a biological treatment tank for biological treatment and a solid-liquid separation device for solid-liquid separation of the water treated in the biological treatment tank. Treated water,
Backwashing water introduction means for backwashing the filtration tower by introducing water filtered by the long fiber filtration device into the filtration tower ;
And fungicides containing water introduction means for sterilizing backwashing the filtration tower by introducing the disinfectant-containing water containing the long fiber filtration is filtered through device water and a chlorine-based germicide inside the filtration tower,
A disinfectant addition amount control means for controlling the addition amount of the disinfectant so that the residual chlorine concentration in the backwash waste water generated by the washing with the disinfectant-containing water is in the range of 1.5 to 10 mg / L;
After pre-performed Kigyaku washing, the wash control means for controlling to perform said disinfecting backwashing,
Water stored in the backwash drainage tank after the backwash drainage discharged from the filtration tower by the backwash and the sterilization backwash drainage discharged from the filtration tower by the sterilization backwash were stored in the backwash drainage tank Return means for returning the biological treatment tank to at least one of the biological treatment tank and the upstream side of the biological treatment tank;
A backwashing device for a long fiber filtration device.
請求項に記載の長繊維ろ過装置の逆洗装置であって、
前記洗浄制御手段は、前記洗浄水による洗浄時間が、前記洗浄水による洗浄時間および前記殺菌剤含有水による洗浄時間を合わせた全洗浄時間の10〜30%の範囲となるように制御することを特徴とする長繊維ろ過装置の逆洗装置。
It is a backwashing device of the long fiber filtration device according to claim 4 ,
The cleaning control means controls the cleaning time with the cleaning water to be in a range of 10 to 30% of the total cleaning time including the cleaning time with the cleaning water and the cleaning time with the disinfectant-containing water. Backwashing device for long fiber filtration device.
請求項4または5に記載のろ過装置の逆洗装置であって、
前記殺菌剤含有水による洗浄の後に前記長繊維束と殺菌剤とを所定の時間接触させる浸漬手段を有することを特徴とする長繊維ろ過装置の逆洗装置。
A backwashing device for a filtration device according to claim 4 or 5 ,
A backwashing device for a long fiber filtration device, comprising dipping means for bringing the long fiber bundle into contact with the bactericide for a predetermined time after washing with the bactericide-containing water.
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