JP3918199B2

JP3918199B2 - Activated carbon treatment equipment

Info

Publication number: JP3918199B2
Application number: JP25242995A
Authority: JP
Inventors: 眞紀子宮原; 克己岡田
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 1995-09-29
Filing date: 1995-09-29
Publication date: 2007-05-23
Anticipated expiration: 2015-09-29
Also published as: JPH0994568A

Description

【０００１】
【発明の属する技術分野】
本発明は活性炭処理装置に係り、特に、少量の殺菌剤で効果的に殺菌処理することができる活性炭処理装置に関する。
【０００２】
【従来の技術】
従来、各種排水のＣＯＤや色度等の難生物分解性物質を処理する方法として、活性炭処理法がある。この方法は、活性炭充填層が形成された活性炭吸着塔内に、被処理排水を上向流又は下向流で通水することにより排水を活性炭と接触させ、活性炭の吸着作用等で、ＣＯＤや色度等を除去する方法である。
【０００３】
活性炭処理法における排水処理のメカニズムは、排水の通水初期においては、主に活性炭による吸着作用によるものであるが、通水を継続することにより、活性炭表面に生物膜が形成され、この生物膜による分解作用が主体となる。この生物膜が過度に成長すると、活性炭の吸着作用が低下し、総合的な処理効率は低下してくる。
【０００４】
このような生物膜の形成で吸着効率が低下した場合、活性炭充填層を逆洗すると共に、微生物の活性を低下させるための殺菌処理を施すことがある。具体的な殺菌方法としては、熱水殺菌、蒸気殺菌、塩素殺菌がある。
【０００５】
この熱水殺菌は、８０℃以上の熱水を１時間以上活性炭吸着塔に通水、保持する方法であるが、生菌量が多く、例えば、１０⁸個／ｍｌ以上の場合には、高温の熱水を長時間通水、保持する必要があり、工業的に有利な方法とは言えない。
【０００６】
また、蒸気殺菌は、１２０℃以上の蒸気を１５分以上通すことで、ほぼ完全な殺菌状態とすることができるが、吸着塔を耐高圧性のものとする必要があり、設備コストが嵩むという不具合がある。
【０００７】
これに対し、塩素殺菌であれば、次亜塩素酸ナトリウム（ＮａＣｌＯ）等の塩素系殺菌剤を添加した薬液を一定量通水することで、上記のような問題を生じることなく、比較的良好な殺菌効果を得ることができる。この塩素殺菌法としては、特開平５−６４７８２号公報に、逆洗水にＮａＣｌＯ等を添加して逆洗を行う方法が提案されている。
【０００８】
【発明が解決しようとする課題】
一般に、排水の活性炭処理においては、下向流で排水を通水処理し、逆洗に当っては上向流洗浄の向流逆洗を行った場合に、最も良好な処理水質を得ることができる。
【０００９】
しかしながら、塩素系殺菌剤は活性炭と接触すると分解してＣｌ^- を生成して殺菌効果が失われるところから、下向流通水を行った活性炭吸着塔を、ＮａＣｌＯ等の塩素系殺菌剤を添加した逆洗水を用いて上向流洗浄を行った場合には、被処理排水の導入側であって、最も生物膜による汚染が激しい活性炭充填層の殺菌が不十分になり易い。即ち、この下降流通水・上向流逆洗の場合、逆洗水中に添加された塩素系殺菌剤はまず活性炭充填層下部の生物膜があまり付着していない活性炭と接触するため、塩素系殺菌剤中の塩素成分の多くが活性炭充填層の下部においてＣｌ^-となってしまい、活性炭充填層の上部までは十分な量の未分解塩素系殺菌剤が供給されないことになる。この結果、生物膜付着量の多く、強い殺菌処理が必要な活性炭充填層上部の殺菌が不十分になってしまう。
【００１０】
下向流通水・上向流逆洗の場合においても、充填層全体を十分に殺菌するためには、活性炭吸着塔内の活性炭充填層高さを低くするか、或いは、殺菌剤を高濃度に添加することが必要となる。しかしながら、活性炭充填層高さを低くする場合には、相対的に、活性炭吸着塔の塔径を大きくする必要があり、装置設置スペースの面で不利である。また、殺菌剤濃度を高めることは、薬剤コストの高騰を招く上に、塩素を分解することで活性炭が消耗するため、好ましいことではない。
【００１１】
本発明は上記従来の問題点を解決し、少量の殺菌剤で塔内を均一かつ効率的に殺菌処理することができる活性炭処理装置を提供することを目的とする。
【００１２】
【課題を解決するための手段】
本発明の活性炭処理装置は、活性炭充填層と逆洗水導入手段とを備える活性炭処理装置において、通水方向に対して多段に設けられた各活性炭充填層にそれぞれ殺菌剤を導入する手段を設けるか、或いは、活性炭充填層の通水方向の末端部と途中部分とに殺菌剤を導入する手段を設けたものであり、各活性炭充填層の高さ、或いは、活性炭充填層における、殺菌剤を導入する手段間の小区画の高さが３０〜５０ｃｍであり、殺菌剤として塩素系殺菌剤を用い、逆洗水通水ＬＶ１０〜２０ｍ／ｈｒ、各活性炭充填層又は各小区画の入口部Ｃｌ _２濃度５〜１０ｍｇ／ｌの条件で殺菌処理が行われるものである。
【００１３】
本発明の活性炭処理装置では、多段に設けた活性炭充填層の各々に殺菌剤を導入するか、或いは、活性炭充填層の途中部分にも殺菌剤を導入することにより、塔内の活性炭を通水方向に対して複数に分割して殺菌処理することができる。このため、少量の殺菌剤使用量で塔内を均一かつ効率的に殺菌処理することができる。
【００１４】
【発明の実施の形態】
以下、図面を参照して本発明の実施例について詳細に説明する。
【００１５】
図１，２は各々本発明の活性炭処理装置の一実施例を示す系統図である。
【００１６】
図１に示す活性炭処理装置１は、活性炭吸着塔２内に、活性炭充填層３Ａ，３Ｂ，３Ｃを多段（本実施例においては、３段であるが、２段或いは４段以上であっても良い。）に形成した多段方式のものであり、各活性炭充填層３Ａ，３Ｂ，３Ｃの下部に殺菌剤導入手段を設けたものである。即ち、各活性炭充填層３Ａ，３Ｂ，３Ｃの下部には、散水板４Ａ，４Ｂ，４Ｃが設けられ、ＮａＣｌＯ水溶液貯槽５内のＮａＣｌＯ水溶液が、ポンプＰ₁ を備える配管６及び各分岐配管６Ａ，６Ｂ，６Ｃを経て注入されるように構成されている。図中、７はポンプＰ₂
を備える逆洗水導入配管であり、逆洗水貯槽８内の逆洗水は、配管７より活性炭吸着塔２の底部より導入され、逆洗排水は、活性炭吸着塔２の頂部より、配管９を経て系外へ排出される。
【００１７】
なお、この活性炭処理装置１の活性炭吸着塔２には、図示しない被処理水の導入配管と処理水の排出配管が設けられており、被処理水が上向流又は下向流、好ましくは下向流で通水処理されるように構成されている。
【００１８】
本実施例の活性炭処理装置１において、活性炭吸着塔２内の殺菌を行うには、ポンプＰ₁ ，Ｐ₂ を作動させて、ＮａＣｌＯ水溶液貯槽５内のＮａＣｌＯ水溶液を配管６及び各分岐配管６Ａ，６Ｂ，６Ｃ、散水板４Ａ，４Ｂ，４Ｃを経て、各活性炭充填層３Ａ，３Ｂ，３Ｃに添加すると共に、逆洗水貯槽８内の逆洗水を所定の通水ＬＶで配管７より上向流通水して逆洗を行う。
【００１９】
これにより、各活性炭充填層３Ａ，３Ｂ，３Ｃは、各々層毎に添加されるＮａＣｌＯにより均一かつ効果的に殺菌される。
【００２０】
なお、図１において、ＮａＣｌＯ水溶液注入配管６Ｃは、逆洗水導入配管７に接続し、ＮａＣｌＯを注入した逆洗水を最下段の散水板４Ｃから導入するようにしても良い。
【００２１】
図２に示す活性炭処理装置１Ａは、活性炭吸着塔２内に１層の活性炭充填層３のみを設けた単層方式のものであり、図２において、図１に示す部材と同一機能を奏する部材には、同一符号を付してある。
【００２２】
本実施例の活性炭処理装置１Ａでは、活性炭充填層３の通水方向の途中部分に散水板４Ａ，４Ｂ，４Ｃを設け、各散水板４Ａ，４Ｂ，４Ｃに、配管６及び配管６Ａ，６Ｂ，６Ｃを経てＮａＣｌＯ水溶液を注入するように構成されると共に、活性炭充填層３の下部に設けられた散水板４Ｄに連通する逆洗水導入配管７にも、配管６及び配管６Ｄを経てＮａＣｌＯ水溶液を注入するように構成されている。
【００２３】
従って、本実施例の活性炭処理装置１Ａでは、配管６Ａ，６Ｂ，６Ｃ，６Ｄ及び散水板４Ａ，４Ｂ，４Ｃ，４Ｄを経て注入されるＮａＣｌＯ水溶液により、活性炭充填層３が散水板間の小区画３ａ，３ｂ，３ｃ，３ｄ毎に殺菌されるようになり、各々の小区画３ａ〜３ｄが均一かつ効率的に殺菌される。
【００２４】
なお、図１の如く、活性炭充填層を多段に設けた場合の各充填層３Ａ〜３Ｃの高さ（第１図のＬ）、或いは、図２の、単層の活性炭充填層３における散水板間の小区画３ａ〜３ｄの高さ（第２図のＬ’）が過度に高い場合、本発明による殺菌効率の改善効果が十分に得られず、殺菌剤濃度の低減が図れない。逆に、このＬ，Ｌ’の値が過度に小さいと装置が複雑化する。従って、Ｌ，Ｌ’は３０〜５０ｃｍとする。また、逆洗時においては、充填層展開率３０％以上、特に３０〜８０％で逆洗を行うのが好ましい。
【００２５】
本発明の活性炭処理装置において、殺菌剤としては、ＮａＣｌＯの他、ＮａＣｌＯ₂ 、サラシ粉等を用いることができ、特にＮａＣｌＯ等の塩素系殺菌剤の添加量が、各活性炭充填層のＣｌ₂濃度、即ち、逆洗排水のＣｌ₂ 濃度が５〜１０ｍｇ／ｌとなるように各殺菌剤導入手段から注入する。
【００２６】
特に、本発明においては、生菌数１０⁵ 〜１０⁸ 個／ｍｌの活性炭吸着塔に対して、逆洗水通水ＬＶ１０〜２０ｍ／ｈｒ、活性炭充填層の入口部Ｃｌ₂濃度５〜１０ｍｇ／ｌの条件で殺菌処理を行う。
【００２７】
また、殺菌処理時間については、長い程殺菌効果が高いが、反面、活性炭がＣｌ₂ を徐々に分解することにより活性炭寿命が短くなる。一般に、塔内生菌数が１０⁶個／ｍｌの場合において、活性炭充填層入口部Ｃｌ₂ 濃度５ｍｇ／ｌで殺菌した場合、１分以内で生菌数１０個／ｍｌ以下に殺菌することが可能であるが、Ｃｌ₂濃度変化を考慮した場合、２０分程度の殺菌処理を行うのが好ましい。
【００２８】
なお、前述の如く、活性炭処理装置においては、被処理水を下向流で通水し、上向流で逆洗水を通水する向流洗浄を行うのが、処理水質の面から最も好適であるが、本発明の活性炭処理装置では、これに限らず、上向流通水及び上向流逆洗の並（順）流洗浄を適用しても良い。
【００２９】
【実施例】
以下、参考例、実施例及び比較例を挙げて本発明をより具体的に説明する。
【００３０】
実施例１，２、参考例１〜３
図１に示すような本発明の活性炭処理装置を用いて、活性炭の逆洗を行った。
【００３１】
直径３０ｍｍ，高さ３０００ｍｍの塩化ビニル製カラムに２０／４０メッシュの活性炭を、高さ５０ｃｍに充填した活性炭充填層を１段、２段又は３段に形成したものを各々準備し、各カラムに水道水を通水処理することにより、活性炭により生菌を繁殖させカラム流出水の生菌数を約１０⁶ 個／ｍｌとした。
【００３２】
各々のカラムに各層の入口部のＣｌ₂ 濃度が表１の値となるようにＮａＣｌＯ水溶液を注入すると共に、逆洗水として水道水を一定のＬＶ（１０ｍ／ｈｒ）で通水し（逆洗時の活性炭展開率３０％）、逆洗開始から１０分後の逆洗排水中の残留Ｃｌ₂濃度と、生菌数を調べ、結果を表１に示した。
【００３３】
【表１】

【００３４】
なお、逆洗水の通水ＬＶを２０ｍ／ｈｒ，充填層展開率８０％として上記と同様の操作を行った場合も同様の結果が得られたが、逆洗水の通水ＬＶを５ｍ／ｈｒとして、上記と同様の操作を行ったところ、層高０．５ｍ，充填層の入口Ｃｌ₂ 濃度２００ｍｇ／ｌの場合であっても残留Ｃｌ₂ は不検出となり、逆洗水の通水ＬＶが低いとＣｌ₂の分解が促進されることが確認された。
【００３５】
これらの結果から、各充填層入口Ｃｌ₂ 濃度を５〜１０ｍｇ／ｌとし、逆洗水通水ＬＶ１０〜２０ｍ／ｈｒとした場合において、効率的な逆洗を行えることがわかる。
【００３６】
比較例１
実施例１，２及び参考例１〜３において、最下段の活性炭充填層にのみＮａＣｌＯ水溶液の注入を行ったところ、層高０．５ｍの場合には、実施例１，２、参考例１〜３と同様の操作が行われるため、同様の結果が得られたが、層高１ｍ及び１．５ｍの場合には、各充填層の入口Ｃｌ₂ 濃度２００ｍｇ／ｌでも、残留Ｃｌ₂ は不検出となり、生菌数は３００〜７００個／ｍｌで、十分な殺菌効果が得られなかった。
【００３７】
【発明の効果】
以上詳述した通り、本発明の活性炭処理装置によれば、少ない殺菌剤使用量で塔内を均一かつ効率的に殺菌することができるため、活性炭充填層高の低減、即ち、装置設置スペースの増大を招くことなく、活性炭処理装置を低コストにかつ効率的に殺菌することができる。
【図面の簡単な説明】
【図１】本発明の活性炭処理装置の一実施例を示す系統図である。
【図２】本発明の活性炭処理装置の他の実施例を示す系統図である。
【符号の説明】
１，１Ａ活性炭処理装置
２活性炭吸着塔
３，３Ａ，３Ｂ，３Ｃ活性炭充填層
４Ａ，４Ｂ，４Ｃ，４Ｄ散水板
５ＮａＣｌＯ水溶液貯槽
８逆洗水貯槽[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an activated carbon treatment apparatus, and more particularly to an activated carbon treatment apparatus that can be effectively sterilized with a small amount of a sterilizing agent.
[0002]
[Prior art]
Conventionally, there is an activated carbon treatment method as a method of treating difficult biodegradable substances such as COD and chromaticity of various wastewaters. In this method, the wastewater to be treated is brought into contact with activated carbon by passing the wastewater to be treated in an upward flow or a downward flow in an activated carbon adsorption tower in which an activated carbon packed bed is formed. This is a method for removing chromaticity and the like.
[0003]
The mechanism of wastewater treatment in the activated carbon treatment method is mainly due to the adsorption action of activated carbon in the initial stage of drainage water flow. By continuing the water flow, a biofilm is formed on the activated carbon surface. Decomposition action by the main. When this biofilm grows excessively, the adsorption action of activated carbon decreases, and the overall treatment efficiency decreases.
[0004]
When the adsorption efficiency decreases due to the formation of such a biofilm, the activated carbon packed bed may be backwashed and sterilized to reduce the activity of microorganisms. Specific sterilization methods include hot water sterilization, steam sterilization, and chlorine sterilization.
[0005]
The hot water sterilization, passed through a 80 ° C. or more hot water in 1 hour or more activated carbon adsorption tower, is a method of retaining, many viable amounts, for example, in the case of more than 10 ⁸ / ml is hot It is necessary to pass and maintain hot water for a long time, which is not an industrially advantageous method.
[0006]
In addition, steam sterilization can be almost completely sterilized by passing steam at 120 ° C. or higher for 15 minutes or more, but it is necessary to make the adsorption tower resistant to high pressure, which increases equipment costs. There is a bug.
[0007]
On the other hand, in the case of chlorine sterilization, a certain amount of chemical solution to which a chlorine-based disinfectant such as sodium hypochlorite (NaClO) is added is relatively good without causing the above problems. Sterilizing effect can be obtained. As this chlorine sterilization method, Japanese Patent Laid-Open No. 5-64782 proposes a method of performing backwashing by adding NaClO or the like to backwashing water.
[0008]
[Problems to be solved by the invention]
Generally, in the activated carbon treatment of wastewater, the best treated water quality can be obtained when the wastewater is treated in the downflow and the backwashing is performed in the upward flow. it can.
[0009]
However, since chlorine-based disinfectant decomposes when it comes into contact with activated carbon and Cl ^- is generated and the disinfection effect is lost, an activated carbon adsorption tower in which downward circulating water is added is added chlorine-based disinfectant such as NaClO. When up-flow washing is performed using backwash water, sterilization of the activated carbon packed bed on the introduction side of the wastewater to be treated and which is most heavily contaminated with the biofilm tends to be insufficient. That is, in the case of this downward circulation water / upward flow backwashing, the chlorine-based disinfectant added to the backwash water first comes into contact with the activated carbon to which the biofilm below the activated carbon packed bed is not attached so much. many chlorine component in the agent Cl at the bottom of the activated carbon packed bed ^- and will become in, so that the undecomposed chlorine-based germicide to the top of the activated carbon packed bed sufficient amount is not supplied. As a result, the sterilization of the upper part of the activated carbon packed bed that requires a large amount of biofilm and requires a strong sterilization treatment becomes insufficient.
[0010]
Even in the case of downward circulating water / upward backwashing, in order to sufficiently sterilize the entire packed bed, the activated carbon packed bed height in the activated carbon adsorption tower should be lowered, or the sterilizing agent should be in a high concentration. It is necessary to add. However, when the activated carbon packed bed height is lowered, it is necessary to relatively increase the diameter of the activated carbon adsorption tower, which is disadvantageous in terms of apparatus installation space. In addition, increasing the concentration of the bactericidal agent is not preferable because the activated carbon is consumed by decomposing chlorine as well as causing an increase in drug cost.
[0011]
An object of the present invention is to solve the above-mentioned conventional problems, and to provide an activated carbon treatment apparatus that can uniformly and efficiently sterilize the inside of a tower with a small amount of a sterilizing agent.
[0012]
[Means for Solving the Problems]
The activated carbon treatment apparatus of the present invention is an activated carbon treatment apparatus provided with an activated carbon packed bed and backwashing water introduction means, and is provided with means for introducing a bactericide into each activated carbon packed bed provided in multiple stages in the direction of water flow. Or, a means for introducing a bactericidal agent is provided at the end portion and the middle portion of the activated carbon packed bed in the direction of water flow, and the height of each activated carbon packed bed or the bactericidal agent in the activated carbon packed bed is changed. the height of the small section between the means for introducing the Ri 30~50cm der, using a chlorine-based germicide as fungicides, backwash water through water LV10~20m / hr, inlet of the activated carbon packed bed or each cubicle conditions sterilization of Cl ₂ concentration 5 to 10 mg / l is shall take place.
[0013]
In the activated carbon treatment apparatus of the present invention, the activated carbon in the tower is allowed to flow by introducing a bactericidal agent into each of the activated carbon packed beds provided in multiple stages or by introducing a bactericidal agent into the middle part of the activated carbon packed bed. The sterilization process can be performed by dividing into a plurality of directions. For this reason, the inside of the tower can be uniformly and efficiently sterilized with a small amount of the sterilizing agent used.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
1 and 2 are system diagrams each showing an embodiment of the activated carbon treatment apparatus of the present invention.
[0016]
The activated carbon treatment apparatus 1 shown in FIG. 1 has activated carbon packed

towers

3A, 3B, 3C in an activated carbon adsorption tower 2 in multiple stages (in this embodiment, three stages, but two stages or four or more stages may be used). It is a multi-stage system formed in the above-described manner, and a disinfectant introduction means is provided below the activated carbon packed

layers

3A, 3B, 3C. That is, the bottom of each activated carbon packed

bed

3A, 3B, 3C,

sprinkler plate

4A, 4B, 4C are provided, NaClO aqueous solution in NaClO solution storage tank 5, the pipe 6 and the branch pipes 6A comprises a pump P _1, It is configured to be injected through 6B and 6C. In the figure, 7 is the pump P ₂
The backwash water in the backwash water storage tank 8 is introduced from the bottom of the activated carbon adsorption tower 2 through the pipe 7, and the backwash drainage from the top of the activated carbon adsorption tower 2 through the pipe 9. It is discharged out of the system through.
[0017]
The activated carbon adsorption tower 2 of the activated carbon treatment apparatus 1 is provided with an unillustrated pipe for the treated water and a drain pipe for the treated water, and the treated water flows upward or downward, preferably downward. It is configured to pass water in countercurrent.
[0018]
In the activated carbon treatment apparatus 1 of the present embodiment, in order to sterilize the activated carbon adsorption tower 2, the pumps P ₁ and P ₂ are operated, and the NaClO aqueous solution in the NaClO aqueous solution storage tank 5 is supplied to the pipe 6 and each

branch pipe

6A, 6B, 6C and

water spray plates

4A, 4B, 4C are added to the respective activated carbon packed

beds

3A, 3B, 3C, and the backwash water in the backwash water storage tank 8 is directed upward from the pipe 7 with a predetermined water flow LV. Backwash with circulating water.
[0019]
Thereby, each activated

carbon filling layer

3A, 3B, 3C is sterilized uniformly and effectively by NaClO added to each layer.
[0020]
In FIG. 1, the NaClO aqueous solution injection pipe 6C may be connected to the backwash water introduction pipe 7 so that backwash water into which NaClO has been injected may be introduced from the lowermost water spray plate 4C.
[0021]
The activated carbon treatment apparatus 1A shown in FIG. 2 is of a single-layer system in which only one activated carbon packed bed 3 is provided in the activated carbon adsorption tower 2, and in FIG. 2, a member having the same function as the member shown in FIG. Are denoted by the same reference numerals.
[0022]
In the activated carbon treatment apparatus 1A of the present embodiment,

water spray plates

4A, 4B, 4C are provided in the middle of the water flow direction of the activated carbon packed bed 3, and the

water spray plates

4A, 4B, 4C are provided with

pipes

6 and 6A, 6B, The NaClO aqueous solution is injected through 6C, and the backwash water introduction pipe 7 communicating with the water spray plate 4D provided at the lower part of the activated carbon packed bed 3 is also supplied with the NaClO aqueous solution through the pipe 6 and the pipe 6D. It is configured to inject.
[0023]
Therefore, in the activated carbon treatment apparatus 1A of the present embodiment, the activated carbon packed layer 3 is divided into small partitions between the water spray plates by the NaClO aqueous solution injected through the

pipes

6A, 6B, 6C, 6D and the

water spray plates

4A, 4B, 4C, 4D. Sterilization is performed for each of 3a, 3b, 3c, and 3d, and each of the small sections 3a to 3d is uniformly and efficiently sterilized.
[0024]
As shown in FIG. 1, the height of each of the packed layers 3 </ b> A to 3 </ b> C (L in FIG. 1) when the activated carbon packed layers are provided in multiple stages, or the water spray plate in the single activated carbon packed layer 3 in FIG. 2. When the height of the small sections 3a to 3d (L ′ in FIG. 2) is excessively high, the effect of improving the sterilization efficiency according to the present invention cannot be sufficiently obtained, and the concentration of the sterilizer cannot be reduced. Conversely, if the values of L and L ′ are excessively small, the apparatus becomes complicated. Accordingly, L and L ′ are 30 to 50 cm. Moreover, at the time of backwashing, it is preferable to perform backwashing at a packed bed development rate of 30% or more, particularly 30 to 80%.
[0025]
In the activated carbon treatment apparatus of the present invention, as the sterilizing agent, NaClO ₂ , NaClO ₂ , salty powder, etc. can be used. In particular , the addition amount of a chlorine-based sterilizing agent such as NaClO is the Cl ₂ concentration of each activated carbon packed bed. , i.e., it injected from the sterilizing agent inlet means so as Cl ₂ concentration of the backwash effluent is 5 to 10 mg / l.
[0026]
In particular, in the present invention, with respect to the activated carbon adsorption tower having 10 ⁵ to 10 ⁸ viable bacteria / ml, the backwash water flow LV is 10 to ₂₀ m / hr, and the Cl ₂ concentration at the inlet portion of the activated carbon packed bed is 5 to 10 mg / hr. It intends line sterilization treatment under the conditions of l.
[0027]
As for the sterilization treatment time, the longer the sterilization effect, the higher the sterilization effect. On the other hand, the activated carbon gradually decomposes Cl ₂ and the activated carbon life is shortened. In general, when the number of viable bacteria in the tower is 10 ⁶ / ml, sterilization with an activated carbon packed bed inlet portion Cl ₂ concentration of 5 mg / l can be sterilized to 10 viable cells or less within 1 minute. Although it is possible, when considering the change in the Cl ₂ concentration, it is preferable to perform sterilization treatment for about 20 minutes.
[0028]
As described above, in the activated carbon treatment apparatus, it is most preferable in terms of the quality of the treated water to perform the countercurrent washing in which the water to be treated is passed downward and the backwash water is passed upward. However, the activated carbon treatment apparatus of the present invention is not limited to this, and parallel (forward) washing of upward circulation water and upward flow backwashing may be applied.
[0029]
【Example】
Hereinafter, the present invention will be described more specifically with reference to reference examples, examples and comparative examples.
[0030]
Examples 1 and 2 and Reference Examples 1 to 3
The activated carbon was washed back using the activated carbon treatment apparatus of the present invention as shown in FIG.
[0031]
Prepare a column of activated carbon with 20/40 mesh activated carbon packed in a 30 mm diameter, 3000 mm high column and a 50 cm high activated carbon packed bed formed in one, two or three stages. By passing tap water through, viable bacteria were propagated by activated carbon, and the viable count of column effluent was about 10 ⁶ cells / ml.
[0032]
A NaClO aqueous solution was injected into each column so that the Cl ₂ concentration at the inlet of each layer was the value shown in Table 1, and tap water was passed as a backwash water at a constant LV (10 m / hr) (backwash). The activated charcoal development rate was 30%), the residual Cl ₂ concentration in the backwash wastewater 10 minutes after the start of backwashing, and the number of viable bacteria were examined. The results are shown in Table 1.
[0033]
[Table 1]

[0034]
The same result was obtained when the same operation was performed with the backwash water flow rate LV of 20 m / hr and the packed bed expansion rate of 80%, but the backwash water flow rate LV was 5 m / hr. When the same operation as above was performed as hr, residual Cl ₂ was not detected even when the bed height was 0.5 m and the inlet Cl ₂ concentration of the packed bed was 200 mg / l, and the backwash water flow LV It was confirmed that the decomposition of Cl ₂ was promoted at a low value.
[0035]
From these results, each filling layer inlet Cl ₂ concentration of 5 to 10 mg / l, in case of the backwash water through water LV10~20m / hr, it is seen that allows efficient backwash.
[0036]
Comparative Example 1
In Examples 1 and 2 and Reference Examples 1 to 3 , when the NaClO aqueous solution was injected only into the lowest activated carbon packed bed, when the layer height was 0.5 m, Examples 1 and 2 and Reference Examples 1 to 2 were used . Since the same operation as in No. 3 was performed, the same result was obtained. However, when the bed height was 1 m and 1.5 m, the residual Cl ₂ was not detected even at the inlet Cl ₂ concentration of 200 mg / l in each packed bed. Thus, the viable count was 300 to 700 / ml, and a sufficient bactericidal effect was not obtained.
[0037]
【The invention's effect】
As described above in detail, according to the activated carbon treatment apparatus of the present invention, the inside of the tower can be uniformly and efficiently sterilized with a small amount of disinfectant used. Without causing an increase, the activated carbon treatment apparatus can be sterilized at low cost and efficiently.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of an activated carbon treatment apparatus of the present invention.
FIG. 2 is a system diagram showing another embodiment of the activated carbon treatment apparatus of the present invention.
[Explanation of symbols]
1, 1A Activated carbon treatment device 2 Activated

carbon adsorption tower

3, 3A, 3B, 3C Activated carbon packed

bed

4A, 4B, 4C, 4D Sprinkling plate 5 NaClO aqueous solution storage tank 8 Backwash water storage tank

Claims

In the activated carbon treatment apparatus comprising the activated carbon packed bed and the backwash water introduction means,
The activated carbon packed bed is provided in multiple stages with respect to the direction of water flow, and is an activated carbon treatment apparatus provided with means for introducing a bactericide into each activated carbon packed bed,
The height of each activated carbon packed bed Ri 30~50cm der, using a chlorine-based germicide as fungicides, backwash water through water LV10~20m / hr, inlet Cl ₂ concentration of the activated carbon packed bed 5 to 10 mg / activated carbon treatment apparatus sterilized under conditions of l is carried out, it characterized in Rukoto.

In the activated carbon treatment apparatus comprising the activated carbon packed bed and the backwash water introduction means,
An activated carbon treatment apparatus provided with means for introducing a bactericidal agent into the end portion and the middle portion of the activated carbon packed bed in the direction of water flow,
In the activated carbon packed bed, Ri height 30~50cm der small compartment between means for introducing sterilizing agent, using a chlorine-based germicide as fungicides, backwash water through water LV10~20m / hr, the small compartment activated carbon treatment apparatus conditions in sterilization of the inlet portion Cl ₂ concentration 5 to 10 mg / l is carried out, characterized in Rukoto.