JP4467809B2 - Method and apparatus for treating water containing organic matter - Google Patents

Description

【００１３】
これらの結果より、塩素イオンを有意に含有する被処理水に対し、オゾン添加とＵＶ照射によるＯＨラジカル処理を行う場合には、被処理水のｐＨ値を予め５程度の弱酸性域に調整すると、そのｐＨ値が徐々に酸性域に変化することが確認された。これは、被処理水に含まれる塩素イオンがＯＨラジカルと反応することにより、塩酸が生成されることによると考えられる。
【００１４】
また、本発明者らは、塩素イオンがＯＨラジカルのスカベンジャーとして作用する点にも着目した。塩素イオンによるＯＨラジカルの捕捉反応の反応速度は、ｐＨ値が９のときには１×１０⁴（mol/L）^-1・sec^-1であるのに対し、ｐＨ値が０．８〜３．４のときには、１．５±０．３×１０¹⁰（mol/L）^-1・sec^-1と、酸性域で比較的大きい（オゾン利用水処理技術（宗宮 功編著、第７７頁）；文献「L.M.Dorfman and G.E.Adams, "Reactivity of the hydroxyl radical in aqueous solution", NSRDS-NBS-46, U.S. Government Printing office, Washington (1973) 」参照）。したがって、塩酸の生成により酸性度が上がってｐＨ値が低下すると、塩素イオンがＯＨラジカルを捕捉し易くなり、ダイオキシン類の分解が更に抑制されると推定される。
【００１５】
本発明者らは、これらの知見に基づき、ＵＶ照射中の被処理水のｐＨ値をダイオキシン類の分解に適した範囲に保持することが極めて有効であるとの認識に到達した。このためには、（１）被処理水中の塩素イオン濃度を減少させる、（２）オゾン添加量を減少させてＯＨラジカルの生成量を低下させる、（３）ＵＶ照射量を減少させる、といった方法が想到される。
【００１６】
しかし、上記（１）を行うには、被処理水を前処理して塩素イオンを除去することが考えられるが、これでは非常に処理コストが掛かってしまう。また、上記（２）により塩酸の発生は抑制されるが、ダイオキシン類の分解も抑えられてしまう。さらに、上記（３）を行うためには、ＵＶランプの出力を低下させたり、被処理水の流量を増大させてＵＶ照射部における被処理水の滞留時間を短くする等が考えられる。ただし、いずれにしてもＯＨラジカルの生成量が低下してしまい、ダイオキシン類が十分に分解されない。また、被処理水の流量を増大させるには、ポンプ出力の増大や配管の大型化が必要であり、装置規模の増大と経済性の悪化を招くおそれがある。
【００１７】
そこで、本発明はこのような事情に鑑みてなされたものであり、被処理水に含まれる塩素イオンの影響を抑制し、被処理水に含まれるダイオキシン類等の有機物の分解性能を向上できる有機物含有水の処理方法及び装置を提供することを目的とする。
【００１８】
【課題を解決するための手段】
本発明による有機物含有水の処理方法は、有機物及び塩素イオンを含有する被処理水にオゾンを添加し、この被処理水にＵＶを照射することにより有機物を分解処理する方法であって、ＵＶ照射後の被処理水のｐＨ値を測定するｐＨ測定工程と、そのｐＨ値の測定値に基づいて、ＵＶが照射されているときの被処理水のｐＨ値が酸性域の所定のｐＨ値となるように、ＵＶ照射前の被処理水、又は、ＵＶが照射されている被処理水に所定量のｐＨ調整剤を添加するｐＨ調整工程とを備えることを特徴とする。
【００１９】
上述の如く、ＵＶ照射後の被処理水のｐＨ値は、酸性域へシフトする傾向にあり、特に被処理水の初期ｐＨ値がダイオキシン類の分解性能に優れる５程度であると、ｐＨ値の低下が著しい。本発明の方法では、まず、ｐＨ測定工程において、そのＵＶ照射後の被処理水のｐＨを測定する。次に、ｐＨ調整工程において、このｐＨ測定値に基づいて、ＵＶ照射後のｐＨ値と所望のｐＨ値との差分を算出し得る。
【００２０】
そして、この差分に応じたｐＨ値の低下を補い得る量のｐＨ調整剤をＵＶ照射前の被処理水、又は、ＵＶ照射中の被処理水に添加する。このとき、ｐＨ値の測定は、連続的及び断続的のいずれで実施しても構わず、また、ｐＨ調整剤を、被処理水の流量に応じて所定の添加率で徐々に添加してもよいし、必要量の一部を断続的に、或いは、全部を一度に添加してもよい。
【００２１】
より具体的には、例えば、ｐＨ測定値と所望のｐＨ値との差分を算出し、この差分値と、ＵＶ照射における被処理水の滞留時間若しくは被処理水の流量（バッチ処理においては被処理水の容量）、及び、ｐＨ調整剤の濃度等とに基づいて、ｐＨ調整剤の添加量又は添加率を求め得る。ここで、ｐＨ調整剤としては、アルカリ剤及び／又はｐＨ値が５前後の領域で緩衝作用を有する緩衝液を用いると好ましい。
【００２２】
ところで、ＵＶ照射後の被処理水には、通常、有機物の分解に消費されなかったオゾンガスが残存している。よって、例えば、被処理水や処理水のプロセス計装の計器校正（例えば、ｐＨ計の校正）、保守等の際に、オゾンが系外に漏出するおそれがある。従来は、これを防止するために、被処理水や処理水が導入される槽内ひいては系内を常時負圧に維持したり、他の密閉手段を設けることで対処していた。こうなると、操作性、保守性等が低下したり、装置構成が複雑・高価になるという不都合があった。
【００２３】
そこで、本発明の有機物含有水の処理方法として、ｐＨ測定工程の前に実施され、紫外線が照射された後の被処理水に含まれるオゾンを分解叉は除去するオゾン分解工程を更に備え、ｐＨ測定工程においては、オゾン分解工程が施された後の被処理水のｐＨ値を測定すると一層好適である。こうすれば、オゾン分解工程において被処理水中の残存オゾンが分解除去されるので、オゾン分解工程を経た後の被処理水の移送系や貯留系等を開放系とすることができる。
【００２４】
そして、オゾン分解工程の後にｐＨ測定工程を実施するので、ｐＨ値の測定を開放系で行うことができ、このような部位にｐＨ計等の計装機器を設置しても、それらの校正時等にオゾンが系外に漏出するおそれがない。よって、系内を常時負圧に維持したり、他の密閉手段を設けていた従来に比して、操作性、保守性を向上でき、しかも装置構成が複雑・高価になることを抑制できる。
【００２５】
さらに、オゾン分解工程において発生するガス成分を、オゾン分解工程における被処理水から分離叉は除去するガス成分除去工程を備えることが望ましい。より具体的には、このようなガス成分を、オゾン分解工程の前に実施される工程に返送すると有用であり、さらに具体的には、ＵＶ照射中の被処理水、叉は、ＵＶ照射前の被処理水中にガス成分を返送する等が例示される。
【００２６】
オゾン分解工程では、例えば、粒状活性炭等の炭素質吸着剤と被処理水とを接触させることによりオゾンを吸着・分解できるが、ＵＶ照射後の被処理水に残存するオゾンがオゾンやオゾン分解によって生じるガスが気相に移行し、それらのガス成分が集積・滞留し易い傾向にある。そうなると、被処理水の流通が阻害されて流路が閉塞するおそれがある。これに対し、ガス成分除去工程を実行すると、オゾン分解が行われている被処理水すなわちオゾン分解が行われている部位からガス成分が分離叉は除去されるので、被処理水の流路の閉塞を抑止できる。また、ガス成分を系内の上流側に返送すれば、ガス成分中のオゾンが外部へ漏出することを防止し得る。
【００２７】
またさらに、ｐＨ調整工程においては、被処理水の所定のｐＨ値を４．５〜５．５に保持するように、又は、被処理水の所定のｐＨ値が４．５〜５．５となるように、ｐＨ調整剤を添加することが望ましい。ＵＶ照射中の被処理水のｐＨ値をこのような範囲に保持すると、ＯＨラジカルによる有機物の分解効率の顕著な低下を十分に防止できると共に、塩素イオンがＯＨラジカルのスキャベンジャーとして作用することをも抑制できる。
【００２８】
また、本発明による有機物含有水の処理装置は、本発明の有機物含有水の処理方法を有効に実施するためのものであり、有機物及び塩素イオンを含有する被処理水にオゾンを添加するオゾン添加部と、オゾンが添加された被処理水の供給部、滞留部及び排出部を有しており、且つ、その滞留部において被処理水にＵＶを照射するＵＶ照射部とを備える装置であって、上記滞留部又は排出部に設けられ、その滞留部又は排出部における被処理水のｐＨ値を測定するｐＨ測定手段と、供給部又は滞留部における被処理水にｐＨ調整剤を添加することが可能であり、且つ、そのｐＨ値の測定値に基づいて、ｐＨ調整剤の添加量を調節するｐＨ調整手段とを備えることを特徴とする。
【００２９】
好ましくは、本発明による有機物含有水の処理装置は、多段に設けられた複数のＵＶ照射部、及び、少なくとも一つのｐＨ測定手段を有しており、ｐＨ調整手段が、ｐＨ測定手段によって測定された被処理水のｐＨ値の測定値に基づいて、このｐＨ測定手段よりも上流側に位置する処理水の供給部又は滞留部に、所定量のｐＨ調整剤を添加することが可能なものであることが望ましい。このようにすれば、ｐＨ値測定が行われた位置よりも下流側にそのｐＨ測定値に基づいた量のｐＨ調整剤を添加するよりも、所望のｐＨ値が達成され易い。
【００３０】
或いは、多段に設けられた複数のＵＶ照射部を有しており、各ＵＶ照射部の排出部にそれぞれｐＨ測定手段が配設されており、ｐＨ調整手段は、各ｐＨ測定手段によって測定された各排出部における被処理水のｐＨ値の各測定値に基づいて、各排出部を有する各ＵＶ照射部の各供給部に、それぞれ所定量のｐＨ調整剤を添加することが可能なものであると好適である。
【００３１】
このようにすれば、ＵＶ照射量が高められ、有機物の分解性能が高められる。また、ＵＶ照射部毎に被処理水のｐＨ値の低下量が異なる傾向にあるのに対し、各ＵＶ照射部にｐＨ測定手段を各々設けると、それらによる各ｐＨ測定値に基づいて各ＵＶ照射部毎にｐＨ値の調整を実施できる。このとき、ｐＨ値測定が行われた排出部を有するＵＶ照射部の次段のＵＶ照射部側に、そのｐＨ測定値に基づいた量のｐＨ調整剤を添加するよりも、その排出部を有するＵＶ照射部の供給部にｐＨ調整剤を添加した方が、所望のｐＨ値を達成し易い利点がある。
【００３２】
また、本発明による他の有機物含有水の処理装置は、有機物及び塩素イオンを含有する被処理水にオゾンを添加するオゾン添加部と、オゾンが添加された被処理水に紫外線を照射する紫外線照射部とを備える装置であって、紫外線照射部の後段に設けられており、紫外線が照射された被処理水に含まれるオゾンを分解叉は除去するオゾン分解部と、オゾン分解部の後段に設けられており、オゾンが分解叉は除去された被処理水のｐＨ値を測定するｐＨ測定手段と、紫外線照射部の上流側にｐＨ調整剤を添加することが可能であり、且つ、ｐＨ値の測定値に基づいて、ｐＨ調整剤の添加量を調節するｐＨ調整手段とを備えるものであってもよい。
【００３３】
さらに、オゾン分解部において発生するガス成分をオゾン分解部よりも上流側、具体的には、紫外線照射部叉は紫外線照射部よりも上流側に返送するガス成分返送部を更に備えると好適である。こうすれば、オゾン分解が行われている被処理水からガス成分が分離叉は除去される。
【００３４】
またさらに、ｐＨ調整手段は、各紫外線照射部における被処理水のｐＨ値を４．５〜５．５に保持するように、又は、その被処理水のｐＨ値が４．５〜５．５となるように、ｐＨ調整剤の添加量を調節するものであると一層好ましい。
【００３５】
【発明の実施の形態】
以下、添付図を参照して本発明に係る実施形態について説明する。図１は、本発明による有機物含有水の処理装置の第１実施形態を示す構成図である。処理装置１００（有機物含有水の処理装置）は、被処理水Ｗが供給される循環槽４０と、循環槽４０から移送される被処理水Ｗにオゾンを添加するオゾナイザー５（オゾン添加部）と、オゾンが添加された被処理水Ｗｏが順次流通されるＵＶ照射部１，２，３を備え、被処理水Ｗ，Ｗｏをバッチ式で循環処理するものである。
【００３６】
ＵＶ照射部１，２，３は、被処理水Ｗｏが滞留する照射槽１１（滞留部）及びこの照射槽１１内に設置されたＵＶランプ１２で構成されている。ＵＶ照射部３と循環槽４０とは、被処理水Ｗｏを循環させるための循環ラインＬ１で接続されている。
【００３７】
また、処理装置１００は、ＵＶ照射部１，２，３の入口側（供給部）及び循環槽４０のそれぞれに、流量調整が可能な開閉弁Ｖ１〜Ｖ４を有する配管を介して接続された貯留槽６を備えている。これらの配管には、流量計Ｆ１〜Ｆ４が設置されている。また、貯留槽６にはｐＨ調整剤Ａが貯留されている。さらに、ＵＶ照射部１，２，３の出口側（排出部）及び循環槽４０には、ｐＨ計Ｈ１，Ｈ２，Ｈ３（ｐＨ測定手段）及びｐＨ計Ｈ４がそれぞれ配設されている。なお、ｐＨ調整剤は、水酸化ナトリウム溶液等のアルカリ剤、及び／又は、ｐＨ値が５前後の領域で緩衝作用を有する緩衝液等を好ましく用いることができる。
【００３８】
さらに、処理装置１００は、インターフェイス８ａ，８ｂ，８ｃと、ＣＰＵ、ＭＰＵ等から成る演算部８１とを有する制御用計算機８を備えている。ｐＨ計Ｈ１〜Ｈ４は、インターフェイス８ａを介して演算部８１に接続されており、ｐＨ値の測定信号が演算部８１に入力される。また、流量計Ｆ１〜Ｆ４は、インターフェイス８ｃを介して演算部８１に接続されており、流量信号が演算部８１に出力される。さらに、開閉弁Ｖ１〜Ｖ４は、インターフェイス８ｂを介して演算部８１と接続されており、演算部８１から出力された流量調整信号が入力される。
【００３９】
このように構成された処理装置１００を用いた本発明による有機物含有水の処理方法の好適な実施形態について説明する。本発明を適用できる被処理水Ｗとしては、特に限定されるものではなく、例えば、廃棄物処分場からの浸出水、工業排水、生活排水、一般汚水、河川湖沼水、汚泥分離水等の有機物を含有する液体又は液状物が挙げられ、これらのうち、ダイオキシン類等の難分解性の有機塩素化合物及び塩素イオンを有意に含有するものに対し、本発明は特に好適である。
【００４０】
まず、このような被処理水Ｗを循環槽４０に供給し、ｐＨ計Ｈ４でそのｐＨ値を測定し、又は、測定しながら、所望のｐＨ値となるように、開閉弁Ｖ４を開き、所定流量で所定時間、ｐＨ調整剤Ａを循環槽４０内に供給する。ここで、ｐＨ値として５前後の値となるようにすると好適である。
【００４１】
具体的には、例えば、ｐＨ計Ｈ４によるｐＨ測定信号を、制御用計算機８へ出力し、演算部８１で所望のｐＨ値とｐＨ測定値との差分を算出し、循環槽４０内の被処理水Ｗの量に応じて必要なｐＨ調整剤Ａの量を求める。演算部８１からは、開閉弁Ｖ４の開信号を開閉弁Ｖ４へ出力する。同時に、流量計Ｆ４の流量信号を制御用計算機８へ出力し、演算部８１でｐＨ調整剤Ａの添加流量を監視しながら、必要量のｐＨ調整剤Ａが循環槽４０へ供給された時点で、演算部８１から開閉弁Ｖ４の閉信号を開閉弁Ｖ４へ出力する。
【００４２】
次に、ポンプＰ２を運転し、ポンプＰ２が設置された配管の開閉弁を開放して被処理水Ｗを循環槽４０からＵＶ照射部１側へ所定流量で移送する。また、この配管を流通する被処理水Ｗに、オゾナイザー５からオゾンを添加し、オゾンが添加された被処理水ＷｏをＵＶ照射部１，２，３へ順次供給する。なお、被処理水Ｗｏの流量を流量計Ｆ０でモニターし、この流量信号をインターフェイス８ｃを介して演算部８１へ出力して監視する。
【００４３】
被処理水ＷｏはＵＶ照射部１，２，３の各照射槽１１内を流通し、流量と照射槽１１の実効容積で決まる所定時間、照射槽１１内に滞留する。この間に、被処理水ＷｏにＵＶランプ１２からＵＶ照射を行う。こうすると、被処理水Ｗｏ中でＯＨラジカルが生成され、このＯＨラジカルが有機物と反応して、その有機物が酸化分解される。それから、各ＵＶ照射部１，２，３でＵＶ照射が施された被処理水Ｗｏを循環槽４０へ返送し、被処理水Ｗと同様のｐＨ調整及びオゾン添加を行い、再び被処理水ＷｏとしてＵＶ照射部１，２，３へ導入して循環処理を実施する。
【００４４】
このような処理において、ＵＶ照射後の被処理水Ｗｏの出口側（排出部）におけるｐＨ値を、ｐＨ計Ｈ１，Ｈ２，Ｈ３によって測定し（ｐＨ測定工程）、これらのｐＨ測定信号を、制御用計算機８へ出力する。制御用計算機８には、被処理水Ｗｏの所望のｐＨ値を記憶させておき、又は、入力し、演算部８１で所望のｐＨ値と各ｐＨ測定値との差分を算出する。
【００４５】
そして、この差分値が有意であれば、演算部８１から、開信号を開閉弁Ｖ１，Ｖ２，Ｖ３へ出力し、各ＵＶ照射部１，２，３における被処理水Ｗｏの供給部に所定量のｐＨ調整剤Ａを貯留槽６から注入する。このように、貯留槽６、ｐＨ調整剤Ａ、開閉弁Ｖ１，Ｖ２，Ｖ３、及び制御用計算機８からｐＨ調整手段が構成される。
【００４６】
このようなｐＨ測定を連続的又は断続的に随時行い、添加量を調節しつつｐＨ調整剤Ａを注入することにより、被処理水ＷｏのｐＨ値の調整を連続的又は断続的に実施する（ｐＨ調整工程）。こうして、各ＵＶ照射部１，２，３でＵＶが照射されている被処理水ＷｏのｐＨ値を酸性域の所定のｐＨ値に保持する。ここで、所定のｐＨ値が好ましくは４．５〜５．５となるようにｐＨ調整剤Ａの添加量を調節すると好適である。
【００４７】
以上説明したように構成された処理装置１００、及びこれを用いた有機物含有水の処理方法によれば、ＵＶ照射部１，２，３において、ＯＨラジカルの酸化能により、難分解性のダイオキシン類等を含む有機物が酸化分解される。有機物の酸化分解によって被処理水中には塩基性物質が生成されると共に、被処理水Ｗ，Ｗｏに含まれていた塩素イオンがＯＨラジカルと反応して塩酸が生じる。
【００４８】
被処理水Ｗ，Ｗｏ中の塩素イオン濃度が数百ｍｇ／Ｌ程度以上であると、塩基性物質よりも塩酸イオンの生成量が比較的多くなり、被処理水Ｗｏ中のｐＨ値は、ＵＶ照射中に酸性側に変化し得る。本発明では、被処理水ＷｏへｐＨ調整剤Ａを添加することにより、そのｐＨ値が不都合な程に酸性側に変化することを防止できる。
【００４９】
しかも、各ＵＶ照射部１，２，３でＵＶ照射を行った後の被処理水ＷｏのｐＨ値を測定し、このｐＨ測定値と所定の（所望の）ｐＨ値との差分を補う量のｐＨ調整剤Ａを添加するので、被処理水ＷｏのｐＨ値をその所定のｐＨ値に十分に保持できる。よって、ＯＨラジカルによる有機物の分解効率を高く維持できる。したがって、従来に比して、被処理水Ｗｏ中に含まれる塩素イオンの影響を十分に抑制でき、これにより、被処理水Ｗｏに含まれるダイオキシン類等の有機物の分解性能を向上できる。
【００５０】
また、上述の如く、ＵＶ照射中の被処理水ＷｏのｐＨ値を４．５〜５．５に保持、又は、４．５〜５．５となるような量のｐＨ調整剤Ａを添加すると好適である。このｐＨ値が４．５未満であると、ＯＨラジカルによる有機物の分解効率が顕著に低下するとともに、塩素イオンがＯＨラジカルのスキャベンジャーとして作用し易く、有機物の分解が一層抑制される傾向にある。一方、このｐＨが５．５を超えると、添加したオゾンの自己分解が速くなるので不都合である。よって、ＵＶ照射中の被処理水ＷｏのｐＨ値をこのような好適な範囲とすることにより、被処理水Ｗｏに含まれるダイオキシン類等の有機物の分解性能を更に向上できる。
【００５１】
さらに、ＵＶ照射部を複数配設し、しかも被処理水Ｗｏを循環させるので、ＵＶ照射量が高められ、有機物の分解性能を一層向上させることが可能となる。またさらに、ＵＶ照射部１，２，３毎に、被処理水ＷｏのｐＨ調整制御を行うので、ＵＶランプ１２の劣化度等により被処理水ＷｏのｐＨ値の変化度が異なる場合にも、被処理水ＷｏのｐＨ値を所定の値に確実に保持できる。よって、極めて安定した有機物の分解処理が可能となる。
【００５２】
さらにまた、例えば、ＵＶ照射部１の排出部で測定したｐＨ値に基づいて算出したｐＨ調整剤Ａの必要量を、そのＵＶ照射部１の供給部に注入するので、その量のｐＨ調整剤ＡをＵＶ照射部２，３側に添加するよりも、被処理水ＷｏのｐＨ値調整を良好に且つ確実に行うことができる。したがって、有機物の分解処理を一層安定且つ良好に実施可能である。
【００５３】
図２は、本発明による有機物含有水の処理装置の第２実施形態を示す構成図である。処理装置１０１（有機物含有水の処理装置）は、循環槽４０に接続されたＵＶ照射部７１の後段に、循環ラインＬ１から分岐する配管Ｌ２を介してオゾン分解塔５１が設けられており、このオゾン分解塔５１に処理水槽５３が接続されたものである。ここで、循環槽４０には、図１に示すｐＨ計Ｈ４、開閉弁Ｖ４及び流量計Ｆ４が設置されておらず、また、ＵＶ照射部７１は、ｐＨ計が設置されていないこと以外は前出の各ＵＶ照射部１，２，３と同様な構成を有している。
【００５４】
また、オゾン分解塔５１には、オゾンを吸着・分解する媒体としての粒状活性炭等の炭素質吸着剤が充填されており、ＵＶ照射部７１を通過した被処理水Ｗｏが通水されながら炭素質吸着剤と接触するようになっている。このオゾン分解塔５１には、配管Ｌ３を介して上記の処理水槽５３が接続されており、オゾンが分解除去された被処理水Ｗｏの一部が処理水槽５３へ導入される。また、オゾン分解塔５１は配管Ｌ４（ガス成分返送部）を介して循環槽４０と接続されており、オゾン分解塔５１において気相に移行したオゾンやオゾンの分解によって生じた酸素等のガス成分を含む混合水が循環槽４０へ返送されるようになっている。
【００５５】
さらに、処理水槽５３内には、ｐＨ計Ｈ５（ｐＨ測定手段）が設置されている。このｐＨ計Ｈ５は、制御用計算機８に接続されており、ｐＨ値の測定信号が制御用計算機８に入力される。なお、処理水槽５３は、ｐＨ計Ｈ５のセンサー部が収納され得る最小の容量を有していれば、その形状寸法は特に制限されない。またさらに、循環槽４０とＵＶ照射部７１とを結ぶ被処理水Ｗの移送配管には、開閉弁Ｖ５及び流量計Ｆ５が設けられた配管を介して貯留槽６、及びオゾナイザー５が接続されている。開閉弁Ｖ５及び流量計Ｆ５は、図１に示す開閉弁Ｖ１〜Ｖ４及び流量計Ｆ１〜Ｆ１と同様にインターフェイスを介して制御用計算機８に接続されている。
【００５６】
このように構成された処理装置１０１を用いた本発明による有機物含有水の処理方法の好適な実施形態について説明する。まず、被処理水Ｗを循環槽４０に供給し、ポンプＰ２を運転して被処理水Ｗを循環槽４０からＵＶ照射部７１側へ所定流量で送出する。この被処理水Ｗに、オゾナイザー５からオゾンを添加し、オゾンが添加された被処理水ＷｏをＵＶ照射部７１内へ供給する。なお、図１に示すように、被処理水Ｗｏの流量を流量計Ｆ０でモニターし、この流量信号をインターフェイス８ｃを介して演算部８１へ出力して監視してもよい。
【００５７】
被処理水ＷｏはＵＶ照射部７１でＵＶ照射が行われ、被処理水Ｗｏ中で生成されるＯＨラジカルにより有機物が酸化分解される。次いで、ＵＶ照射が行われた被処理水Ｗｏの一部を循環ラインＬ１を通して循環槽４０へ移送し、他部を配管Ｌ２を通してオゾン分解塔５１へ移送する。後者の被処理水Ｗｏはオゾン分解塔５１内を流下叉は流上し、内部に充填された炭素質吸着剤と接触する。これにより、被処理水Ｗｏ中に残存するオゾンが炭素質吸着剤に吸着且つ分解される。このとき、オゾン分解塔５１内では、被処理水Ｗｏに含まれていたオゾン等のガス成分が発生するが、このようなガス成分を含む気液混合水を配管Ｌ４を通して循環槽４０へ返送する（ガス成分除去工程）。
【００５８】
さらに、オゾンが十分に除去された被処理水Ｗｏの一部を、配管Ｌ３を通して処理水槽５３へ流入させ、ｐＨ計Ｈ５によるｐＨ測定を行う（第２のｐＨ測定工程）。その後、処理水槽５３内の被処理水Ｗｏは処理水Ｗｓとして外部へ排出される。ｐＨ計Ｈ５からのｐＨ測定信号は、制御用計算機８へ出力され、被処理水Ｗｏに対する所望のｐＨ値とｐＨ計Ｈ５で取得したｐＨ測定値との差分を算出する。この差分値が有意であれば、循環槽４０内へ返送された被処理水Ｗｏの量に応じて必要なｐＨ調整剤Ａの量を求める。
【００５９】
そして、制御用計算機８から、開信号を開閉弁Ｖ５へ出力し、循環槽４０とＵＶ照射部７１とを結ぶ被処理水Ｗの移送配管へ所定量のｐＨ調整剤Ａを貯留槽６から注入する。このように、貯留槽６、ｐＨ調整剤Ａ、開閉弁Ｖ５、及び制御用計算機８からｐＨ調整手段が構成されている。ここで、オゾン分解塔５１内の被処理水ＷｏのｐＨが好ましくは４．５〜５．５となるようにｐＨ調整剤Ａの添加量を調節すると好適である。
【００６０】
このように構成された処理装置１０１及びこれによる有機物含有水の処理方法によれば、ＵＶ照射部７１において有機物の分解に消費されなかったオゾンが含まれる被処理水中のそのような残存オゾンが分解除去されるので、ｐＨ測定を行うための処理水槽５３やｐＨ計Ｈ５を含む部分を開放系にすることが可能である。よって、ｐＨ計Ｈ５の計器校正時等にオゾンが系外に漏出するおそれがない。
【００６１】
また、処理水槽５３における被処理水ＷｏのｐＨ測定値に基づいてＵＶ照射部７１へ流入する被処理水ＷｏのｐＨ値を所望の値に調整できるので、循環槽４０及びＵＶ照射部７１にｐＨ計を設けてｐＨ調整を行わなくとも、被処理水Ｗｏ中の有機物の分解性能を十分に向上できる利点がある。さらに、これらより、ｐＨ計等の計器校正等に際してオゾンが系外へ漏出するおそれがないので、処理装置の系内を常時負圧に維持したり、他の密閉手段を設けていた従来に比して、操作性、保守性を格段に向上できる。しかも、装置構成が複雑・高価になることを十分に抑制できる。
【００６２】
またさらに、オゾン分解塔５１内で発生するガス成分を含む混合水を循環槽４０へ返送するので、オゾン分解塔５１内にガス成分が集積・滞留することを防止できる。これにより、オゾン分解塔５１内に充填された炭素質吸着剤中を流通する被処理水Ｗｏの移動が阻害されることが抑制される。したがって、オゾン分解塔５１内の流路が閉塞することを抑止でき、被処理水Ｗｏ中のオゾン分解処理を良好に維持できる。さらにまた、オゾンを含み得るガス成分が系内に戻入されることにより、そのオゾンが外部へ漏出することを十分に防止できる。なお、循環槽４０内に滞積するガス成分を、排ガスＧｈとして図示しないガス処理系へ排出してもよい。また、これら以外の効果は、前述した処理装置１００におけるのと同様であるので、ここでの説明は省略する。
【００６３】
図３は、本発明による有機物含有水の処理装置の第３実施形態を示す構成図である。処理装置１０２（有機物含有水の処理装置）は、ＵＶ照射部７１の上部及び下部にポンプＰ３及び開閉弁を有する配管Ｌ５が設けられ、配管Ｌ５から分岐する配管Ｌ２に接続されたオゾン分解塔５１、及びその後段に設けられた処理水槽５３を有するものである。この処理装置１０２では、ＵＶ照射部７１でＵＶ照射が行われた被処理水Ｗｏの一部が、ＵＶ照射部７１に直接返送され、且つ、他部がオゾン分解塔５１を経てＵＶ照射部７１に返送され、これらにより被処理水Ｗ，Ｗｏの循環処理が行われる。
【００６４】
このように構成された処理装置１０２によっても、図２に示す処理装置１０１と同様に、ｐＨ計Ｈ５のｐＨ測定値に基づいて被処理水ＷｏのｐＨ調整が行われ、被処理水Ｗｏ中の有機物を十分に且つ安定に分解できる。よって、ｐＨ計Ｈ５の校正時等にオゾンが系外へ漏出することがない。また、ＵＶ照射後の被処理水Ｗｏ及びオゾン分解塔５１からの被処理水Ｗｏを、循環槽４０を介さずにＵＶ照射部７１へ返送するので、装置構成をより簡略化できると共に、被処理水ＷｏのｐＨ調整をより確実に実施できる。なお、これら以外の効果は、前述した処理装置１０１におけるのと同様であるので、ここでの説明は省略する。
【００６５】
図４は、本発明による有機物含有水の処理装置の第４実施形態を示す構成図である。処理装置１０３は、循環ラインＬ１から分岐する配管Ｌ２を介してＵＶ照射部３に接続されたオゾン分解塔５１と、その後段に配置された処理水槽５３とを更に備えつつ、ｐＨ計Ｈ４を有しないこと以外は、主として、図１に示す処理装置１００と同様に構成されたものである。また、オゾン分解塔５１は配管Ｌ４を介して循環槽４０に接続されている。
【００６６】
このような構成の処理装置１０３においては、循環槽４０における被処理水Ｗ，ＷｏのｐＨ調整を、処理水槽５３においてｐＨ計Ｈ５で取得したｐＨ測定値に基づいて実施できる。よって、循環槽４０におけるｐＨ計の計器校正等の保守が不要であるので、図１に示す処理装置１００に比してオゾン漏出の可能性を低減できる利点がある。
【００６７】
なお、処理装置１０３においては、ＵＶ照射部１，２，３にそれぞれ設けたｐＨ計Ｈ１，Ｈ２，Ｈ３のうちの一部叉は全部を省略してもよい。また、処理装置１００，１０３では、図３に示す処理装置１０２の如く、ＵＶ照射した被処理水Ｗｏを直接ＵＶ照射部に返送して循環処理してもよい。また、バッチ処理の場合には、処理水Ｗｓを循環槽４０叉はＵＶ照射部１，２，３に戻入してもよい。
【００６８】
さらに、制御用計算機８は必ずしも必要ではなく、ｐＨ測定値に基づいてｐＨ調整剤Ａの添加量を手動で算出し、開閉弁Ｖ１〜Ｖ５を手動で操作し、必要量のｐＨ調整剤Ａを被処理水Ｗｏに手動で添加してもよい。またさらに、ｐＨ計Ｈ１，Ｈ２，Ｈ３叉はそれらのセンサー部を配管ではなくＵＶ照射部１，２，３の各照射槽１１に設けてもよい。さらにまた、ｐＨ計は、少なくともいずれか一つの照射槽１１に対して設けられていてもよい。この場合、そのｐＨ計よりも上流側に位置する被処理水Ｗｏの供給部にｐＨ調整剤Ａを添加することが好ましい。
【００６９】
また、ｐＨ調整剤Ａの供給用配管をＵＶ照射部１，２，３の各照射槽１１に直接接続してもよい。さらに、ポンプＰ２，Ｐ３を制御用計算機８に接続して、被処理水Ｗｏの流量を可変制御するようにしてもよい。加えて、被処理水の処理形態としては、バッチ循環処理ではなく、連続処理でも構わない。
【００７０】
【実施例】
以下、実施例により本発明を更に詳しく説明するが、本発明は、これらの実施例に限定されるものではない。
【００７１】
〈実施例１〉
まず、一般廃棄物最終処分場からの浸出水を採取し、この浸出水に炭酸ナトリウム（Ｎａ₂ＣＯ₃）を加えてカルシウム（Ｃａ）を沈殿させ、これを沈降分離した。上澄み水に１ｍｏｌ／Ｌの塩酸を添加してｐＨ値を略５に調整したものを被処理水とし、図１に示す処理装置１００と同様の構成を有する装置を用いて処理を行なった。
【００７２】
この被処理水に含まれる塩素イオン濃度を測定したところ３８００ｍｇ／Ｌであった。また、被処理水の循環流量を３０Ｌ／ｍｉｎ、オゾンガス（オゾン含有量：７４．５ｇ−Ｏ₃／Ｎｍ³）の給気流量を１．７６ＮＬ／ｍｉｎとし、ＵＶランプ１２として、紫外線出力（強度）５０Ｗのものを使用した。また、図１には示さない熱交換器を処理装置１００に接続し、被処理水Ｗｏの温度を４０℃以下に保持した。さらに、ｐＨ調整剤Ａとして１％水酸化ナトリウム溶液を用い、各ＵＶ照射部１，２，３における被処理水ＷｏのｐＨ値を、４．８〜５．２の範囲内の値に保持した。
【００７３】
〈比較例１〉
ｐＨ調整剤Ａを添加しなかったこと以外は、実施例１と同様にして同量の被処理水を循環処理した。
【００７４】
〈有機塩素化合物の分析〉
実施例１及び比較例１で処理した被処理水Ｗｏを所定時間間隔でサンプリングし、すなわち、オゾン添加量と処理時間が異なる種々の試料を採取し、この試料中の有機塩素化合物の含有濃度を分析した。また、同様に処理前の被処理水中に含まれる有機塩素化合物の含有濃度も分析した。分析対象は、ポリ塩化ジベンゾパラジオキシン（ＰＣＤＤｓ）、ポリ塩化ジベンゾフラン（ＰＣＤＦｓ）、コプラナーポリ塩化ビフェニル（コプラナーＰＣＢｓ）の総量とし、厚生省マニュアル（平成９年２月２６日付通知）（或いは、日本工業規格ＪＩＳ Ｋ０３１２（１９９９））に準拠し、高分解能ガスクロマトグラフ／高分解能質量分析計（ＨＲＧＣ／ＨＲＭＳ）によって各同族体を定量し、毒性等価換算した値を積算してダイオキシン類の実測濃度とした。
【００７５】
その結果、処理前の被処理水中に含まれるダイオキシン類の実測濃度は、４８ｐｇ／Ｌであった。また、この処理前の実測濃度に対する各処理試料中のダイオキシン類の実測濃度（百分率）を、ダイオキシン類残存率として図６に示す。図６に示すように、実施例１におけるオゾン添加量に対するダイオキシン類の残存率は、比較例１に比して格段に小さいことが確認された。一例として、オゾン添加量が３００ｇ−Ｏ₃／ｍ³におけるダイオキシン類の残存率は、実施例１では１０％（９０％除去）であるのに対し、比較例１では約７０％（約３０％除去）であった。また、オゾン添加量に対するダイオキシン類の残存率の低下率も実施例１の方が大きいことが確認された。
【００７６】
〈実施例２〉
まず、一般廃棄物最終処分場からの浸出水処理水に、ダイオキシン類等の有機塩素化合物の前駆物質の一つである１，２，３−トリクロロベンゼン（以下、「ＴＣＢ」という）を溶解させ、ＴＣＢ濃度が２０ｍｇ／Ｌ、ｐＨが７．３である被処理水を調製した。この被処理水を、図２に示す処理装置１０１と同等の構成を有する装置を用いて処理した。
【００７７】
このとき、被処理水の供給量（循環流量）を３Ｌ／ｍｉｎ、循環槽４０の容量を１０Ｌ、オゾンの供給量を９０ｍｇ−Ｏ₃／ｍｉｎとし、ＵＶランプ１２として、紫外線出力（強度）２０Ｗの低圧水銀ランプを使用した。また、オゾン分解塔５１（容量３Ｌ）には粒状活性炭を充填し、処理水槽５３の容量は２Ｌとした。さらに、ｐＨ調整剤Ａとして水酸化ナトリウム溶液及び硫酸溶液を用い、ＵＶ照射部７１における被処理水ＷｏのｐＨ値を、５．０〜６．０の範囲内の値となるように保持した。
【００７８】
〈ＴＣＢ及びオゾンの分析〉
実施例２において、オゾン分解塔５１の入口部及び出口部において被処理水Ｗｏをサンプリングし、入口部及び出口部における被処理水Ｗｏ中のＴＣＢ濃度、並びに、出口部における被処理水Ｗｏ中のオゾン濃度を分析した。その結果、入口部及び出口部サンプリング水中のＴＣＢ濃度は、それぞれ４．１ｍｇ／Ｌ及び３．２ｍｇ／Ｌであり、ＴＣＢ濃度を初期の２０ｍｇ／Ｌに比して格段に低減できることが確認された。また、出口部サンプリング水中のオゾン濃度は略０ｍｇ／Ｌであり、被処理水Ｗｏ中に残存するオゾンを略完全に除去できることが確認された。さらに、処理水槽５３の上部気相において、オゾン臭は全く認められなかった。
【００７９】
【発明の効果】
以上説明したように、本発明の有機物含有水の処理方法及び装置によれば、被処理水に含まれる塩素イオンの影響を抑制し、被処理水に含まれるダイオキシン類等の有機物の分解性能を格別に向上できる。
【図面の簡単な説明】
【図１】本発明による有機物含有水の処理装置の第１実施形態を示す構成図である。
【図２】本発明による有機物含有水の処理装置の第２実施形態を示す構成図である。
【図３】本発明による有機物含有水の処理装置の第３実施形態を示す構成図である。
【図４】本発明による有機物含有水の処理装置の第４実施形態を示す構成図である。
【図５】試験装置の構成を示すブロック図である。
【図６】実施例１及び比較例１におけるダイオキシン類残存率を示すグラフである。
【符号の説明】
１，２，３…ＵＶ照射部（紫外線照射部）、５…オゾナイザー（オゾン添加部）、６…貯留槽（ｐＨ調整手段）、８…制御用計算機（ｐＨ調整手段）、１１…照射槽（被処理水の滞留部）、１２…ＵＶランプ、４０…循環槽、５１…オゾン分解塔（オゾン分解部）、１００，１０１，１０２，１０３…処理装置（有機物含有水の処理装置）、Ａ…ｐＨ調整剤、Ｆ１，Ｆ２，Ｆ３…流量計、Ｈ１，Ｈ２，Ｈ３，Ｈ５…ｐＨ計（ｐＨ測定手段）、Ｌ４…配管（ガス成分返送部）、Ｖ１，Ｖ２，Ｖ３，Ｖ５…開閉弁（ｐＨ調整手段）、Ｗ，Ｗｏ…被処理水。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for treating organic substance-containing water, and more specifically, an organic substance-containing water treatment method comprising treating an organic chlorine compound such as dioxins as an organic compound and treating water to be treated containing chlorine ions, and Relates to the device.
[0002]
[Prior art]
Conventionally, as a method for treating water to be treated such as leachate containing an organic chlorine compound such as dioxins and oxidizing and decomposing dioxins, there is a method described in JP-A-7-108285, for example. This method is intended to remove dioxins in sewage (treated water) and is one of treated water and treated water (treated by supplying ozone to treated water under ultraviolet irradiation). Part is introduced into a pH adjusting tank, the pH value is adjusted to neutral or weakly acidic, ozone is added thereto, and ultraviolet irradiation is performed.
[0003]
[Problems to be solved by the invention]
By the way, the present inventors have found that when leachate from a final disposal site for general waste is treated by the conventional method, dioxins tend not to be sufficiently decomposed and removed. In general, when ozone is supplied under ultraviolet irradiation to generate OH radicals, and dioxins are oxidatively decomposed by the OH radicals, it is efficient to set the pH value of the water to be treated to a weak acidity of about 5. However, in the conventional method, although the pH is adjusted to be weakly acidic, dioxins in the leachate are not sufficiently removed as described above.
[0004]
Therefore, as a result of intensive studies, the present inventors have confirmed that the pH value of the water to be treated during ultraviolet irradiation gradually changes to the acidic side mainly due to the influence of chlorine ions contained in the water to be treated. Specifically, a pH measurement test of the water to be treated was performed using the test apparatus shown in FIG.
[0005]
FIG. 5 is a block diagram showing the configuration of this test apparatus. In this test apparatus, ultraviolet (hereinafter referred to as “UV”) irradiation units 1, 2, 3 that sequentially irradiate the water W to be treated with ultraviolet rays are connected. The processing procedure of the to-be-processed water W in this test apparatus is as follows.
[0006]
First, the to-be-processed water W stored in the raw water tank 20 is transferred to the adjustment tank 4 by the pump P1, and ozone is added from the ozonizer 5 that generates ozone. The treated water Wo to which ozone was added was adjusted in pH by the adjustment tank 4 and confirmed to have a predetermined pH value by the pH meter H4, and then the UV irradiation unit 1, 2, 3 by the pump P2. Are successively supplied. The water to be treated Wo receives UV irradiation from the UV lamp 12 (output: 50 W) when it flows through the irradiation tank 11 constituting each UV irradiation unit 1, 2, 3. The treated water Wo that has passed through the UV irradiation unit 3 is transferred to the treated water tank 30.
[0007]
At this time, the pH value of the water to be treated Wo is measured by the pH meters H1, H2, and H3 provided on the outlet sides (that is, the discharge portions) of the respective UV irradiation units 1, 2, and 3. Further, the pH value of the water to be treated Wo immediately before the UV irradiation unit 1 is measured by a pH meter H0 provided on the inlet side (that is, the supply unit) of the UV irradiation unit 1. The flow meter F0 is for monitoring the discharge amount of the pump P2 so that the residence time of the water to be treated Wo in the irradiation tank 11 becomes a predetermined value.
[0008]
<Test 1>
A test apparatus having such a configuration is supplied with a solution in which sodium chloride is dissolved in pure water so as to have a concentration of 12000 mg / L as the water to be treated W, so that the pH value is approximately 5 in the adjustment tank 4. It was adjusted. This chlorine ion concentration is slightly higher than the chlorine ion concentration (often about 500 to 5000 mg / L) that can be contained in the leachate from a general waste disposal site in order to make it easier to confirm the influence of chlorine ions. A high concentration was set. To this treated water W, ozone gas (ozone content: 74.5 g-O _Three / Nm ^Three ) At a flow rate of 1.76 NL / min was sent to the UV irradiation units 1, 2, and 3 at a flow rate of 30 L / min. The residence time of the water to be treated Wo in the UV irradiation units 1, 2, and 3 was all 17.9 sec.
[0009]
<Test 2>
UV irradiation was performed in the same manner as in Test 1 except that the pH value of the water to be treated W was adjusted to approximately 7 in the adjustment tank 4.
[0010]
<Test 3>
Except that the UV lamps 12 were not all turned on, the water to be treated Wo was circulated to the UV irradiation units 1, 2, and 3 in the same manner as in Test 1.
[0011]
<PH value measurement results>
In Tests 1 to 3, pH values measured by the pH meters H0, H1, H2, and H3 are shown in Table 1.
[0012]
[Table 1]

[0013]
From these results, when the OH radical treatment by ozone addition and UV irradiation is performed on the water to be treated containing chlorine ions significantly, the pH value of the water to be treated is adjusted to a weakly acidic range of about 5 in advance. It was confirmed that the pH value gradually changed to the acidic range. This is considered to be due to the generation of hydrochloric acid by the reaction of chlorine ions contained in the water to be treated with OH radicals.
[0014]
The present inventors also focused on the point that chlorine ions act as scavengers for OH radicals. The reaction rate of the scavenging reaction of OH radicals by chloride ions is 1 × 10 when the pH value is 9. ^Four (Mol / L) ^-1 ・ Sec ^-1 On the other hand, when the pH value is 0.8 to 3.4, 1.5 ± 0.3 × 10 ^Ten (Mol / L) ^-1 ・ Sec ^-1 And relatively large in the acidic region (Ozone-utilized water treatment technology (written by Isao Munemiya, p. 77)); literature “LMDorfman and GEAdams,“ Reactivity of the hydroxyl radical in aqueous solution ”, NSRDS-NBS-46, US Government Printing office, Washington (1973) ”). Therefore, when the acidity increases due to the generation of hydrochloric acid and the pH value decreases, it is presumed that chlorine ions easily capture OH radicals, and the decomposition of dioxins is further suppressed.
[0015]
Based on these findings, the present inventors have reached the recognition that it is extremely effective to maintain the pH value of the water to be treated during UV irradiation in a range suitable for the decomposition of dioxins. For this purpose, (1) the chlorine ion concentration in the water to be treated is reduced, (2) the amount of ozone added is reduced to reduce the amount of OH radicals produced, and (3) the amount of UV irradiation is reduced. Is conceived.
[0016]
However, in order to carry out the above (1), it is conceivable to pre-treat the water to be treated to remove chlorine ions, but this results in a very high processing cost. Moreover, although generation | occurrence | production of hydrochloric acid is suppressed by said (2), decomposition | disassembly of dioxins will also be suppressed. Furthermore, in order to perform the above (3), it is conceivable to reduce the residence time of the water to be treated in the UV irradiation unit by reducing the output of the UV lamp or increasing the flow rate of the water to be treated. However, in any case, the amount of OH radicals produced decreases and dioxins are not sufficiently decomposed. Further, in order to increase the flow rate of the water to be treated, it is necessary to increase the pump output and increase the size of the piping, which may increase the scale of the apparatus and deteriorate the economy.
[0017]
Therefore, the present invention has been made in view of such circumstances, and an organic substance that can suppress the influence of chlorine ions contained in the water to be treated and can improve the decomposition performance of organic substances such as dioxins contained in the water to be treated. It aims at providing the processing method and apparatus of contained water.
[0018]
[Means for Solving the Problems]
The method for treating organic matter-containing water according to the present invention is a method for decomposing organic matter by adding ozone to the water to be treated containing organic matter and chlorine ions, and irradiating the water to be treated with UV. Based on the pH measurement step for measuring the pH value of the water to be treated later and the measured value of the pH value, the pH value of the water to be treated when irradiated with UV becomes a predetermined pH value in the acidic range. Thus, it is characterized by including the pH adjustment process of adding a predetermined amount of pH adjuster to the to-be-processed water before UV irradiation, or the to-be-processed water irradiated with UV.
[0019]
As described above, the pH value of the water to be treated after UV irradiation tends to shift to the acidic range. In particular, when the initial pH value of the water to be treated is about 5 which is excellent in dioxin decomposition performance, The decline is remarkable. In the method of the present invention, first, in the pH measurement step, the pH of the water to be treated after the UV irradiation is measured. Next, in the pH adjustment step, the difference between the pH value after UV irradiation and the desired pH value can be calculated based on the measured pH value.
[0020]
And the pH adjuster of the quantity which can compensate the fall of the pH value according to this difference is added to the to-be-processed water before UV irradiation, or the to-be-processed water during UV irradiation. At this time, the measurement of the pH value may be performed either continuously or intermittently, and the pH adjuster may be gradually added at a predetermined addition rate according to the flow rate of the water to be treated. It is also possible to add a part of the required amount intermittently or all at once.
[0021]
More specifically, for example, the difference between the measured pH value and the desired pH value is calculated, and the difference value and the residence time of the treated water in the UV irradiation or the flow rate of the treated water (in batch processing, Based on the volume of water) and the concentration of the pH adjusting agent, the addition amount or addition rate of the pH adjusting agent can be determined. Here, as the pH adjuster, it is preferable to use an alkaline agent and / or a buffer solution having a buffering action in a region where the pH value is around 5.
[0022]
By the way, normally, ozone gas that has not been consumed for decomposition of organic matter remains in the water to be treated after UV irradiation. Therefore, for example, ozone may leak out of the system during instrument calibration (for example, calibration of a pH meter) or maintenance of process instrumentation of treated water or treated water. Conventionally, in order to prevent this, the inside of the tank into which the water to be treated and the treated water are introduced, that is, the inside of the system is always maintained at a negative pressure, or other sealing means is provided. In this case, there are inconveniences such as operability, maintainability and the like, and the device configuration becomes complicated and expensive.
[0023]
Therefore, the organic substance-containing water treatment method of the present invention further includes an ozone decomposition step that is performed before the pH measurement step and decomposes or removes ozone contained in the water to be treated after being irradiated with ultraviolet rays. In the measurement step, it is more preferable to measure the pH value of the water to be treated after the ozonolysis step. If it carries out like this, since the residual ozone in to-be-processed water is decomposed and removed in an ozone decomposition process, the transfer system of the to-be-processed water after passing through an ozone decomposition process, a storage system, etc. can be made into an open system.
[0024]
Since the pH measurement step is performed after the ozonolysis step, the pH value can be measured in an open system, and even if instrumentation equipment such as a pH meter is installed in such a site, There is no risk of ozone leaking out of the system. Therefore, it is possible to improve operability and maintainability as compared with the conventional case where the system is always maintained at a negative pressure or other sealing means is provided, and the apparatus configuration can be prevented from becoming complicated and expensive.
[0025]
Furthermore, it is desirable to provide a gas component removal step for separating or removing the gas component generated in the ozone decomposition step from the water to be treated in the ozone decomposition step. More specifically, it is useful to return such a gas component to a process performed before the ozonolysis process, and more specifically, water to be treated during UV irradiation, or before UV irradiation. For example, the gas component is returned to the water to be treated.
[0026]
In the ozone decomposing step, for example, ozone can be adsorbed and decomposed by bringing a carbonaceous adsorbent such as granular activated carbon into contact with the water to be treated. However, ozone remaining in the water to be treated after UV irradiation is caused by ozone or ozone decomposition. The resulting gas moves to the gas phase, and these gas components tend to accumulate and stay. If so, the flow of the water to be treated may be hindered and the flow path may be blocked. On the other hand, when the gas component removal step is executed, the gas component is separated or removed from the water to be treated in which ozone decomposition is performed, that is, the portion in which ozone decomposition is performed. Blocking can be suppressed. Moreover, if the gas component is returned to the upstream side in the system, the ozone in the gas component can be prevented from leaking outside.
[0027]
Furthermore, in the pH adjustment step, the predetermined pH value of the water to be treated is maintained at 4.5 to 5.5, or the predetermined pH value of the water to be treated is 4.5 to 5.5. Thus, it is desirable to add a pH adjusting agent. If the pH value of the water to be treated during UV irradiation is kept in such a range, it is possible to sufficiently prevent a significant decrease in the decomposition efficiency of organic substances due to OH radicals, and that chlorine ions act as a scavenger for OH radicals. Can also be suppressed.
[0028]
Moreover, the treatment apparatus for organic matter-containing water according to the present invention is for effectively carrying out the treatment method for organic matter-containing water according to the present invention, and ozone addition for adding ozone to water to be treated containing organic matter and chlorine ions. And a UV irradiation unit that irradiates UV to the water to be treated in the staying part. A pH measuring means provided in the staying part or the discharge part, for measuring the pH value of the water to be treated in the staying part or the discharge part, and adding a pH adjuster to the water to be treated in the supply part or the staying part. And pH adjusting means for adjusting the amount of the pH adjusting agent added based on the measured value of the pH value.
[0029]
Preferably, the organic substance-containing water treatment apparatus according to the present invention includes a plurality of UV irradiation units provided in multiple stages and at least one pH measurement unit, and the pH adjustment unit is measured by the pH measurement unit. Based on the measured value of the pH value of the water to be treated, a predetermined amount of pH adjusting agent can be added to the supply portion or the retention portion of the treated water located upstream from the pH measuring means. It is desirable to be. In this way, a desired pH value can be achieved more easily than adding an amount of a pH adjusting agent based on the measured pH value downstream of the position where the measured pH value is measured.
[0030]
Alternatively, it has a plurality of UV irradiation units provided in multiple stages, and pH measuring means are arranged at the discharge part of each UV irradiation unit, and the pH adjusting means was measured by each pH measuring means. Based on each measured value of the pH value of the water to be treated in each discharge unit, a predetermined amount of pH adjuster can be added to each supply unit of each UV irradiation unit having each discharge unit. It is preferable.
[0031]
In this way, the UV irradiation amount can be increased and the decomposition performance of organic matter can be improved. In addition, although the amount of decrease in the pH value of the water to be treated tends to be different for each UV irradiation unit, if each UV irradiation unit is provided with a pH measurement means, each UV irradiation is performed based on each pH measurement value by them. The pH value can be adjusted for each part. At this time, rather than adding a pH adjuster in an amount based on the measured pH value to the UV irradiation part next to the UV irradiation part having the discharging part in which the pH value measurement is performed, the discharging part is provided. The addition of a pH adjusting agent to the supply unit of the UV irradiation unit has an advantage of easily achieving a desired pH value.
[0032]
In addition, another organic material-containing water treatment apparatus according to the present invention includes an ozone addition unit for adding ozone to water to be treated containing organic matter and chlorine ions, and ultraviolet irradiation for irradiating ultraviolet rays to the water to be treated to which ozone has been added. And an ozone decomposing unit that decomposes or removes ozone contained in the water to be treated that has been irradiated with ultraviolet light, and is provided after the ozone decomposing unit. PH measuring means for measuring the pH value of the water to be treated from which ozone has been decomposed or removed, and a pH adjusting agent can be added upstream of the ultraviolet irradiation section, and A pH adjusting means for adjusting the amount of the pH adjusting agent added based on the measured value may be provided.
[0033]
Furthermore, it is preferable to further include a gas component returning unit that returns the gas component generated in the ozone decomposing unit to the upstream side of the ozone decomposing unit, specifically, the ultraviolet irradiation unit or the upstream side of the ultraviolet irradiation unit. . In this way, the gas component is separated or removed from the water to be treated that has undergone ozonolysis.
[0034]
Still further, the pH adjusting means maintains the pH value of the water to be treated in each ultraviolet irradiation section at 4.5 to 5.5, or the pH value of the water to be treated is 4.5 to 5.5. It is more preferable to adjust the addition amount of the pH adjuster so that
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing a first embodiment of a treatment apparatus for organic substance-containing water according to the present invention. The treatment device 100 (treatment device for organic substance-containing water) includes a circulation tank 40 to which the water to be treated W is supplied, and an ozonizer 5 (ozone addition unit) that adds ozone to the water to be treated W transferred from the circulation tank 40. The UV treatment units 1, 2 and 3 through which the water to be treated Wo added with ozone is sequentially distributed are provided to circulate the water to be treated W and Wo in a batch manner.
[0036]
The UV irradiation units 1, 2, and 3 are configured by an irradiation tank 11 (retention part) in which the water to be treated Wo stays and a UV lamp 12 installed in the irradiation tank 11. The UV irradiation unit 3 and the circulation tank 40 are connected by a circulation line L1 for circulating the water to be treated Wo.
[0037]
Moreover, the processing apparatus 100 is a storage connected to the inlet side (supply unit) of the UV irradiation units 1, 2, and 3 and the circulation tank 40 via pipes having on-off valves V <b> 1 to V <b> 4 capable of adjusting the flow rate. A tank 6 is provided. These pipes are provided with flow meters F1 to F4. Further, the pH adjusting agent A is stored in the storage tank 6. Furthermore, pH meters H1, H2, H3 (pH measuring means) and a pH meter H4 are disposed on the outlet side (discharge unit) of the UV irradiation units 1, 2, 3 and the circulation tank 40, respectively. As the pH adjuster, an alkali agent such as a sodium hydroxide solution and / or a buffer solution having a buffering action in a region where the pH value is around 5 can be preferably used.
[0038]
Furthermore, the processing apparatus 100 includes a control computer 8 having interfaces 8a, 8b, and 8c and a calculation unit 81 that includes a CPU, MPU, and the like. The pH meters H1 to H4 are connected to the calculation unit 81 via the interface 8a, and a pH value measurement signal is input to the calculation unit 81. Further, the flow meters F <b> 1 to F <b> 4 are connected to the calculation unit 81 via the interface 8 c, and a flow rate signal is output to the calculation unit 81. Furthermore, the on-off valves V1 to V4 are connected to the calculation unit 81 via the interface 8b, and the flow rate adjustment signal output from the calculation unit 81 is input.
[0039]
The preferred embodiment of the processing method of the organic substance containing water by this invention using the processing apparatus 100 comprised in this way is described. The treated water W to which the present invention can be applied is not particularly limited. For example, organic substances such as leachate from a waste disposal site, industrial wastewater, domestic wastewater, general wastewater, river lake water, sludge separation water, etc. Among them, the present invention is particularly suitable for those containing significantly difficult-to-decompose organic chlorine compounds such as dioxins and chlorine ions.
[0040]
First, such water to be treated W is supplied to the circulation tank 40, and the pH value is measured by the pH meter H4, or the open / close valve V4 is opened so that the desired pH value is obtained while measuring the predetermined value. The pH adjusting agent A is supplied into the circulation tank 40 at a flow rate for a predetermined time. Here, it is preferable that the pH value is about 5.
[0041]
Specifically, for example, a pH measurement signal from the pH meter H4 is output to the control computer 8, the difference between the desired pH value and the measured pH value is calculated by the calculation unit 81, and the object to be processed in the circulation tank 40 is calculated. The amount of pH adjuster A required is determined according to the amount of water W. From the calculation part 81, the opening signal of the on-off valve V4 is output to the on-off valve V4. At the same time, when the flow rate signal of the flow meter F4 is output to the control computer 8 and the addition flow rate of the pH adjuster A is monitored by the calculation unit 81, the required amount of the pH adjuster A is supplied to the circulation tank 40. The operation unit 81 outputs a closing signal for the opening / closing valve V4 to the opening / closing valve V4.
[0042]
Next, the pump P2 is operated, the opening / closing valve of the pipe where the pump P2 is installed is opened, and the water to be treated W is transferred from the circulation tank 40 to the UV irradiation unit 1 side at a predetermined flow rate. Further, ozone is added from the ozonizer 5 to the water to be treated W flowing through this pipe, and the water to be treated Wo to which ozone is added is sequentially supplied to the UV irradiation units 1, 2, and 3. In addition, the flow volume of the to-be-processed water Wo is monitored with the flowmeter F0, and this flow volume signal is output to the calculating part 81 via the interface 8c, and is monitored.
[0043]
The treated water Wo flows through the irradiation tanks 11 of the UV irradiation units 1, 2, and 3 and stays in the irradiation tank 11 for a predetermined time determined by the flow rate and the effective volume of the irradiation tank 11. During this time, the UV water 12 is irradiated with UV from the water to be treated Wo. If it carries out like this, OH radical will be produced | generated in the to-be-processed water Wo, this OH radical will react with organic substance, and the organic substance will be oxidatively decomposed. Then, the water to be treated Wo that has been subjected to UV irradiation in each of the UV irradiation units 1, 2, 3 is returned to the circulation tank 40, pH adjustment and ozone addition similar to the water to be treated W are performed, and the water to be treated Wo is treated again. As shown in FIG.
[0044]
In such treatment, the pH value at the outlet side (discharge part) of the water to be treated Wo after UV irradiation is measured by pH meters H1, H2, and H3 (pH measurement step), and these pH measurement signals are controlled. Output to the computer 8. The control computer 8 stores or inputs a desired pH value of the water to be treated Wo, and the calculation unit 81 calculates a difference between the desired pH value and each measured pH value.
[0045]
If the difference value is significant, the calculation unit 81 outputs an open signal to the on-off valves V1, V2, and V3, and supplies a predetermined amount to the supply portion of the water to be treated Wo in each of the UV irradiation units 1, 2, and 3. The pH adjusting agent A is injected from the storage tank 6. In this way, the storage tank 6, the pH adjuster A, the on-off valves V1, V2, V3, and the control computer 8 constitute a pH adjusting means.
[0046]
Such pH measurement is performed continuously or intermittently as needed, and the pH value of the water to be treated Wo is adjusted continuously or intermittently by injecting the pH adjuster A while adjusting the addition amount ( pH adjustment step). In this way, the pH value of the water to be treated Wo irradiated with UV in each of the UV irradiation units 1, 2, and 3 is maintained at a predetermined pH value in the acidic range. Here, it is suitable to adjust the addition amount of the pH adjuster A so that the predetermined pH value is preferably 4.5 to 5.5.
[0047]
According to the processing apparatus 100 configured as described above and the organic substance-containing water processing method using the processing apparatus 100, in the UV irradiation units 1, 2, and 3, the OH radical oxidizing ability makes it difficult to decompose dioxins. Organic matter containing etc. is oxidized and decomposed. A basic substance is generated in the water to be treated by oxidative decomposition of the organic matter, and chlorine ions contained in the water to be treated W and Wo react with OH radicals to generate hydrochloric acid.
[0048]
If the chlorine ion concentration in the water to be treated W and Wo is about several hundred mg / L or more, the amount of hydrochloric acid ions generated is relatively larger than that of the basic substance, and the pH value in the water to be treated Wo is UV. It can change to the acidic side during irradiation. In the present invention, by adding the pH adjuster A to the water to be treated Wo, it is possible to prevent the pH value from being changed to an inconveniently acidic side.
[0049]
In addition, the pH value of the water to be treated Wo after the UV irradiation is performed by each UV irradiation unit 1, 2, 3 is measured, and the amount of the amount that compensates for the difference between the measured pH value and a predetermined (desired) pH value. Since the pH adjuster A is added, the pH value of the water to be treated Wo can be sufficiently maintained at the predetermined pH value. Therefore, the decomposition efficiency of organic substances by OH radicals can be maintained high. Therefore, compared with the past, the influence of the chlorine ion contained in the to-be-processed water Wo can fully be suppressed, and, thereby, the decomposition performance of organic substances, such as dioxins contained in the to-be-processed water Wo, can be improved.
[0050]
Further, as described above, the pH value of the water to be treated Wo during UV irradiation is maintained at 4.5 to 5.5, or the pH adjuster A is added in such an amount as to be 4.5 to 5.5. Is preferred. When this pH value is less than 4.5, the decomposition efficiency of organic substances by OH radicals is remarkably lowered, and chlorine ions tend to act as scavengers for OH radicals, and the decomposition of organic substances tends to be further suppressed. . On the other hand, if the pH exceeds 5.5, it is inconvenient because the self-decomposition of the added ozone becomes faster. Therefore, by setting the pH value of the water to be treated Wo during UV irradiation to such a suitable range, the decomposition performance of organic substances such as dioxins contained in the water to be treated Wo can be further improved.
[0051]
Furthermore, since a plurality of UV irradiation sections are disposed and the water to be treated Wo is circulated, the UV irradiation amount can be increased, and the organic substance decomposition performance can be further improved. Furthermore, since the pH adjustment control of the water to be treated Wo is performed for each of the UV irradiation units 1, 2 and 3, even when the degree of change in the pH value of the water to be treated Wo varies depending on the degree of deterioration of the UV lamp 12, etc. The pH value of the water to be treated Wo can be reliably maintained at a predetermined value. Therefore, it is possible to perform an extremely stable decomposition process of organic substances.
[0052]
Furthermore, for example, since the necessary amount of the pH adjusting agent A calculated based on the pH value measured at the discharge unit of the UV irradiation unit 1 is injected into the supply unit of the UV irradiation unit 1, the amount of the pH adjusting agent is injected. The pH value of the water to be treated Wo can be adjusted better and more reliably than when A is added to the UV irradiation units 2 and 3 side. Therefore, it is possible to more stably and satisfactorily carry out the organic substance decomposition treatment.
[0053]
FIG. 2 is a block diagram showing a second embodiment of the apparatus for treating organic substance-containing water according to the present invention. The treatment apparatus 101 (organic substance-containing water treatment apparatus) is provided with an ozonolysis tower 51 via a pipe L2 branched from the circulation line L1 at the rear stage of the UV irradiation unit 71 connected to the circulation tank 40. A treated water tank 53 is connected to the ozonolysis tower 51. Here, the pH meter H4, the on-off valve V4, and the flow meter F4 shown in FIG. 1 are not installed in the circulation tank 40, and the UV irradiation unit 71 is the same as the previous one except that the pH meter is not installed. It has the same configuration as each of the UV irradiation units 1, 2, and 3 described above.
[0054]
The ozone decomposing tower 51 is filled with a carbonaceous adsorbent such as granular activated carbon as a medium for adsorbing and decomposing ozone, and the carbonaceous material is passed through the water to be treated Wo passing through the UV irradiation unit 71. It comes in contact with the adsorbent. The treated water tank 53 is connected to the ozonolysis tower 51 via a pipe L <b> 3, and a part of the treated water Wo from which ozone is decomposed and removed is introduced into the treated water tank 53. The ozone decomposing tower 51 is connected to the circulation tank 40 via a pipe L4 (gas component returning unit), and the gas component such as ozone transferred to the gas phase in the ozone decomposing tower 51 or oxygen generated by the decomposition of ozone. The mixed water containing the water is returned to the circulation tank 40.
[0055]
Further, a pH meter H5 (pH measuring means) is installed in the treated water tank 53. The pH meter H <b> 5 is connected to the control computer 8, and a pH value measurement signal is input to the control computer 8. In addition, if the treated water tank 53 has the minimum capacity | capacitance which can accommodate the sensor part of pH meter H5, the shape dimension will not be restrict | limited in particular. Furthermore, the storage tank 6 and the ozonizer 5 are connected to the transfer pipe of the water W to be treated that connects the circulation tank 40 and the UV irradiation unit 71 through a pipe provided with the on-off valve V5 and the flow meter F5. Yes. The on-off valve V5 and the flow meter F5 are connected to the control computer 8 through an interface in the same manner as the on-off valves V1 to V4 and the flow meters F1 to F1 shown in FIG.
[0056]
A preferred embodiment of the method for treating organic substance-containing water according to the present invention using the treatment apparatus 101 configured as described above will be described. First, the water to be treated W is supplied to the circulation tank 40, and the pump P2 is operated to deliver the water to be treated W from the circulation tank 40 to the UV irradiation unit 71 side at a predetermined flow rate. Ozone is added to the water to be treated W from the ozonizer 5, and the water to be treated Wo to which ozone is added is supplied into the UV irradiation unit 71. In addition, as shown in FIG. 1, you may monitor the flow volume of the to-be-processed water Wo with the flowmeter F0, and may output and monitor this flow volume signal to the calculating part 81 via the interface 8c.
[0057]
The water to be treated Wo is irradiated with UV by the UV irradiation unit 71, and the organic matter is oxidatively decomposed by OH radicals generated in the water to be treated Wo. Next, a part of the water to be treated Wo irradiated with UV is transferred to the circulation tank 40 through the circulation line L1, and the other part is transferred to the ozonolysis tower 51 through the pipe L2. The latter treated water Wo flows down or flows up in the ozonolysis tower 51 and comes into contact with the carbonaceous adsorbent filled therein. As a result, ozone remaining in the water to be treated Wo is adsorbed and decomposed by the carbonaceous adsorbent. At this time, gas components such as ozone contained in the water to be treated Wo are generated in the ozone decomposition tower 51, and the gas-liquid mixed water containing such gas components is returned to the circulation tank 40 through the pipe L4. (Gas component removal step).
[0058]
Further, a part of the water to be treated Wo from which ozone is sufficiently removed is caused to flow into the treated water tank 53 through the pipe L3, and the pH is measured by the pH meter H5 (second pH measuring step). Thereafter, the water to be treated Wo in the treated water tank 53 is discharged to the outside as treated water Ws. The pH measurement signal from the pH meter H5 is output to the control computer 8, and the difference between the desired pH value for the water to be treated Wo and the pH measurement value acquired by the pH meter H5 is calculated. If this difference value is significant, the amount of the pH adjusting agent A required is determined according to the amount of the water to be treated Wo returned into the circulation tank 40.
[0059]
Then, an open signal is output from the control computer 8 to the on-off valve V5, and a predetermined amount of the pH adjusting agent A is injected from the storage tank 6 into the transfer pipe of the water to be treated W connecting the circulation tank 40 and the UV irradiation unit 71. To do. In this way, the storage tank 6, the pH adjusting agent A, the on-off valve V5, and the control computer 8 constitute a pH adjusting means. Here, it is preferable to adjust the addition amount of the pH adjuster A so that the pH of the water to be treated Wo in the ozonolysis tower 51 is preferably 4.5 to 5.5.
[0060]
According to the processing apparatus 101 configured as described above and the organic substance-containing water treatment method using the treatment apparatus 101, such residual ozone in the water to be treated containing ozone that has not been consumed in the decomposition of the organic substance in the UV irradiation unit 71 is decomposed. Since it is removed, the part including the treated water tank 53 and the pH meter H5 for measuring pH can be opened. Therefore, there is no possibility that ozone leaks out of the system when the pH meter H5 is calibrated.
[0061]
Moreover, since the pH value of the to-be-processed water Wo which flows into the UV irradiation part 71 can be adjusted to a desired value based on the measured pH value of the to-be-processed water Wo in the processing water tank 53, it is pH in the circulation tank 40 and the UV irradiation part 71. There is an advantage that the decomposition performance of the organic matter in the water to be treated Wo can be sufficiently improved without adjusting the pH by providing a meter. Furthermore, since there is no risk of ozone leaking out of the system during calibration of a meter such as a pH meter, it is possible to maintain a negative pressure in the system of the processing apparatus at all times or to provide other sealing means. Thus, the operability and maintainability can be greatly improved. In addition, the device configuration can be sufficiently suppressed from becoming complicated and expensive.
[0062]
Furthermore, since the mixed water containing the gas component generated in the ozone decomposition tower 51 is returned to the circulation tank 40, the gas component can be prevented from accumulating and staying in the ozone decomposition tower 51. Thereby, it is suppressed that the movement of the to-be-processed water Wo which distribute | circulates the inside of the carbonaceous adsorbent filled in the ozonolysis tower 51 is inhibited. Therefore, it can suppress that the flow path in the ozone decomposition tower 51 is obstruct | occluded, and can maintain the ozone decomposition process in the to-be-processed water Wo favorably. Furthermore, when the gas component that can contain ozone is returned into the system, the ozone can be sufficiently prevented from leaking outside. In addition, you may discharge | emit the gas component stagnated in the circulation tank 40 to the gas processing system which is not shown in figure as waste gas Gh. In addition, since the effects other than these are the same as those in the processing apparatus 100 described above, description thereof is omitted here.
[0063]
FIG. 3 is a block diagram showing a third embodiment of the apparatus for treating organic substance-containing water according to the present invention. The treatment apparatus 102 (treatment apparatus for organic matter-containing water) is provided with a pipe L5 having a pump P3 and an opening / closing valve at the upper and lower parts of the UV irradiation unit 71, and connected to a pipe L2 branched from the pipe L5. And a treated water tank 53 provided in the subsequent stage. In the processing apparatus 102, a part of the water to be treated Wo irradiated with the UV irradiation unit 71 is directly returned to the UV irradiation unit 71, and the other part passes through the ozonolysis tower 51 and the UV irradiation unit 71. In this way, the water to be treated W and Wo are circulated.
[0064]
Similarly to the processing apparatus 101 shown in FIG. 2, the processing apparatus 102 configured as described above adjusts the pH of the water to be treated Wo based on the pH measurement value of the pH meter H5, Organic substances can be decomposed sufficiently and stably. Therefore, ozone does not leak out of the system when the pH meter H5 is calibrated. Moreover, since the to-be-processed water Wo after UV irradiation and the to-be-processed water Wo from the ozonolysis tower 51 are returned to the UV irradiation part 71 not via the circulation tank 40, while being able to simplify an apparatus structure more, to-be-processed The pH adjustment of water Wo can be implemented more reliably. Since effects other than these are the same as those in the processing apparatus 101 described above, description thereof is omitted here.
[0065]
FIG. 4 is a block diagram showing a fourth embodiment of the apparatus for treating organic substance-containing water according to the present invention. The treatment apparatus 103 further includes an ozonolysis tower 51 connected to the UV irradiation unit 3 via a pipe L2 branched from the circulation line L1, and a treatment water tank 53 disposed in the subsequent stage, and has a pH meter H4. Except not, it is mainly configured similarly to the processing apparatus 100 shown in FIG. Further, the ozonolysis tower 51 is connected to the circulation tank 40 through a pipe L4.
[0066]
In the treatment apparatus 103 having such a configuration, the pH adjustment of the water to be treated W and Wo in the circulation tank 40 can be performed based on the measured pH value obtained by the pH meter H5 in the treatment water tank 53. Therefore, since maintenance such as calibration of the pH meter in the circulation tank 40 is unnecessary, there is an advantage that the possibility of ozone leakage can be reduced as compared with the processing apparatus 100 shown in FIG.
[0067]
In the processing apparatus 103, some or all of the pH meters H1, H2, and H3 provided in the UV irradiation units 1, 2, and 3 may be omitted. Further, in the processing apparatuses 100 and 103, as in the processing apparatus 102 shown in FIG. 3, the water to be treated Wo irradiated with UV may be directly returned to the UV irradiation unit to be circulated. In the case of batch processing, the treated water Ws may be returned to the circulation tank 40 or the UV irradiation units 1, 2 and 3.
[0068]
Further, the control computer 8 is not necessarily required, the amount of the pH adjuster A is manually calculated based on the measured pH value, the on-off valves V1 to V5 are manually operated, and the required amount of the pH adjuster A is determined. You may add to the to-be-processed water Wo manually. Furthermore, the pH meters H1, H2, H3 or their sensor units may be provided in the irradiation tanks 11 of the UV irradiation units 1, 2, 3 instead of the pipes. Furthermore, the pH meter may be provided for at least one of the irradiation tanks 11. In this case, it is preferable to add the pH adjuster A to the supply portion of the water to be treated Wo positioned on the upstream side of the pH meter.
[0069]
Moreover, the supply pipe for the pH adjusting agent A may be directly connected to the irradiation tanks 11 of the UV irradiation units 1, 2 and 3. Further, the pumps P2 and P3 may be connected to the control computer 8 to variably control the flow rate of the water to be treated Wo. In addition, the treatment form of the water to be treated may be continuous treatment instead of batch circulation treatment.
[0070]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples.
[0071]
<Example 1>
First, leachate from the general waste final disposal site is collected, and sodium carbonate (Na ₂ CO _Three ) Was added to precipitate calcium (Ca), which was separated by settling. Water treated with 1 mol / L hydrochloric acid added to the supernatant water and adjusted to a pH value of about 5 was treated water, and the treatment was performed using an apparatus having the same structure as the treatment apparatus 100 shown in FIG.
[0072]
The chlorine ion concentration contained in the water to be treated was measured and found to be 3800 mg / L. Moreover, the circulation flow rate of the water to be treated is 30 L / min, ozone gas (ozone content: 74.5 g-O _Three / Nm ^Three ) Was set to 1.76 NL / min, and the UV lamp 12 having an ultraviolet output (intensity) of 50 W was used. Moreover, the heat exchanger which is not shown in FIG. 1 was connected to the processing apparatus 100, and the temperature of the to-be-processed water Wo was kept below 40 degreeC. Further, a 1% sodium hydroxide solution was used as the pH adjuster A, and the pH value of the water to be treated Wo in each of the UV irradiation units 1, 2, and 3 was maintained at a value within the range of 4.8 to 5.2. .
[0073]
<Comparative example 1>
The same amount of water to be treated was circulated in the same manner as in Example 1 except that the pH adjuster A was not added.
[0074]
<Analysis of organochlorine compounds>
The water to be treated Wo treated in Example 1 and Comparative Example 1 was sampled at a predetermined time interval, that is, various samples with different ozone addition amounts and treatment times were collected, and the content of organochlorine compound in this sample was determined. analyzed. Similarly, the content concentration of the organic chlorine compound contained in the water to be treated before treatment was also analyzed. The subject of analysis is the total amount of polychlorinated dibenzopararadioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (coplanar PCBs). The Ministry of Health and Welfare Manual (notice dated February 26, 1997) (or Japanese Industrial Standards) In accordance with JIS K0312 (1999)), each homologue was quantified by a high resolution gas chromatograph / high resolution mass spectrometer (HRGC / HRMS), and the values equivalent to toxicity equivalents were integrated to obtain the actual concentration of dioxins.
[0075]
As a result, the measured concentration of dioxins contained in the water to be treated before treatment was 48 pg / L. Moreover, the measured concentration (percentage) of dioxins in each treated sample with respect to the measured concentration before the treatment is shown in FIG. 6 as the dioxin residual rate. As shown in FIG. 6, it was confirmed that the residual rate of dioxins with respect to the amount of ozone added in Example 1 was much smaller than that in Comparative Example 1. As an example, the ozone addition amount is 300 g-O. _Three / M ^Three In Example 1, the residual ratio of dioxins in Example 1 was 10% (90% removed), whereas in Comparative Example 1, it was about 70% (about 30% removed). Moreover, it was confirmed that the rate of decrease in the residual rate of dioxins with respect to the amount of ozone added was larger in Example 1.
[0076]
<Example 2>
First, 1,2,3-trichlorobenzene (hereinafter referred to as “TCB”), one of the precursors of organic chlorine compounds such as dioxins, is dissolved in the leachate treated water from the general waste final disposal site. Water to be treated having a TCB concentration of 20 mg / L and a pH of 7.3 was prepared. This to-be-processed water was processed using the apparatus which has the structure equivalent to the processing apparatus 101 shown in FIG.
[0077]
At this time, the supply amount (circulation flow rate) of the water to be treated is 3 L / min, the capacity of the circulation tank 40 is 10 L, and the supply amount of ozone is 90 mg-O. _Three As a UV lamp 12, a low-pressure mercury lamp having an ultraviolet output (intensity) of 20 W was used. The ozone decomposition tower 51 (capacity 3 L) was filled with granular activated carbon, and the capacity of the treated water tank 53 was 2 L. Furthermore, a sodium hydroxide solution and a sulfuric acid solution were used as the pH adjuster A, and the pH value of the water to be treated Wo in the UV irradiation unit 71 was maintained so as to be a value within the range of 5.0 to 6.0.
[0078]
<Analysis of TCB and ozone>
In Example 2, the to-be-processed water Wo is sampled in the inlet part and exit part of the ozonolysis tower 51, the TCB concentration in the to-be-processed water Wo in an inlet part and an exit part, and in the to-be-processed water Wo in an exit part The ozone concentration was analyzed. As a result, the TCB concentrations in the inlet and outlet sampling waters were 4.1 mg / L and 3.2 mg / L, respectively, and it was confirmed that the TCB concentration can be significantly reduced compared to the initial 20 mg / L. . Further, the ozone concentration in the outlet sampling water was approximately 0 mg / L, and it was confirmed that the ozone remaining in the water to be treated Wo could be removed almost completely. Furthermore, no ozone odor was observed in the upper gas phase of the treated water tank 53.
[0079]
【The invention's effect】
As described above, according to the method and apparatus for treating organic substance-containing water of the present invention, the influence of chlorine ions contained in the treated water is suppressed, and the decomposition performance of organic substances such as dioxins contained in the treated water is improved. It can be exceptionally improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a first embodiment of an apparatus for treating organic substance-containing water according to the present invention.
FIG. 2 is a configuration diagram showing a second embodiment of the apparatus for treating organic substance-containing water according to the present invention.
FIG. 3 is a block diagram showing a third embodiment of the apparatus for treating organic substance-containing water according to the present invention.
FIG. 4 is a block diagram showing a fourth embodiment of the apparatus for treating organic substance-containing water according to the present invention.
FIG. 5 is a block diagram showing a configuration of a test apparatus.
6 is a graph showing the dioxin residual rate in Example 1 and Comparative Example 1. FIG.
[Explanation of symbols]
1, 2, 3 ... UV irradiation part (ultraviolet irradiation part), 5 ... Ozonizer (ozone addition part), 6 ... Storage tank (pH adjustment means), 8 ... Control computer (pH adjustment means), 11 ... Irradiation tank ( (Retaining portion of water to be treated), 12 ... UV lamp, 40 ... circulation tank, 51 ... Ozone decomposition tower (ozone decomposition portion), 100, 101, 102, 103 ... treatment device (treatment device for organic substance-containing water), A ... pH adjuster, F1, F2, F3 ... flow meter, H1, H2, H3, H5 ... pH meter (pH measuring means), L4 ... piping (gas component return part), V1, V2, V3, V5 ... on-off valve ( pH adjusting means), W, Wo: treated water.

Claims (10)

An organic matter-containing water treatment method comprising decomposing the organic matter by adding ozone to the treated water containing organic matter and chlorine ions, and irradiating the treated water with ultraviolet rays,
A pH measurement step for measuring the pH value of the water to be treated after being irradiated with the ultraviolet rays;
Based on the measured value of the pH value, the water to be treated before being irradiated with the ultraviolet rays so that the pH value of the water to be treated when being irradiated with the ultraviolet rays becomes a predetermined pH value in the acidic region, Alternatively, a pH adjusting step of adding a predetermined amount of pH adjusting agent to the water to be treated irradiated with the ultraviolet rays,
A method for treating water containing organic matter, comprising: Further comprising an ozonolysis step that is performed before the pH measurement step and decomposes or removes the ozone contained in the water to be treated after being irradiated with the ultraviolet rays;
In the pH measurement step, the pH value of the water to be treated after the ozonolysis step is measured,
The processing method of the organic substance containing water of Claim 1 characterized by the above-mentioned. A gas component removal step for separating or removing a gas component generated in the ozonolysis step from water to be treated in the ozonolysis step;
The method for treating organic substance-containing water according to claim 2, further comprising: In the pH adjustment step, the predetermined pH value of the treated water is maintained at 4.5 to 5.5, or the predetermined pH value of the treated water is 4.5 to 5.5. Adding the pH adjusting agent,
The processing method of the organic substance containing water as described in any one of Claims 1-3 characterized by the above-mentioned. It has an ozone addition part for adding ozone to the water to be treated containing organic matter and chlorine ions, and a supply part, a retention part and a discharge part for the treated water to which the ozone is added, and the retention part And an ultraviolet irradiation unit for irradiating the water to be treated with ultraviolet rays, and a treatment apparatus for water containing organic matter,
PH measuring means provided in the staying part or the discharge part, for measuring a pH value of water to be treated in the staying part or the discharge part;
A pH adjusting means capable of adding a pH adjusting agent to the water to be treated in the supply unit or the staying unit, and adjusting an addition amount of the pH adjusting agent based on a measured value of the pH value; ,
An organic matter-containing water treatment apparatus comprising: A plurality of the ultraviolet irradiation units provided in multiple stages, and at least one pH measurement means;
The pH adjusting means is disposed in the treated water supply part or the staying part located upstream from the pH measuring means based on the measured value of the pH value of the treated water measured by the pH measuring means. 6. The apparatus for treating organic substance-containing water according to claim 5, wherein a fixed amount of the pH adjusting agent can be added. It has a plurality of the ultraviolet irradiation units provided in multiple stages,
The pH measuring means is disposed in the discharge part of each ultraviolet irradiation part,
The pH adjusting means is based on the measured values of the pH value of the water to be treated in the discharge sections measured by the pH measurement means, and the supply sections of the ultraviolet irradiation sections having the discharge sections. A predetermined amount of the pH adjusting agent can be added to each.
The apparatus for treating organic substance-containing water according to claim 5. An organic matter-containing water treatment apparatus comprising: an ozone addition unit that adds ozone to water to be treated containing organic matter and chlorine ions; and an ultraviolet irradiation unit that irradiates ultraviolet rays to the water to be treated to which the ozone is added. And
An ozone decomposing unit that is provided downstream of the ultraviolet irradiating unit and decomposes or removes ozone contained in the water to be treated irradiated with the ultraviolet ray;
PH measuring means provided at the subsequent stage of the ozone decomposing unit, and measuring the pH value of the water to be treated from which the ozone has been decomposed or removed
A pH adjusting means capable of adding a pH adjusting agent upstream of the ultraviolet irradiation section, and adjusting the addition amount of the pH adjusting agent based on the measured value of the pH value;
An organic matter-containing water treatment apparatus comprising: A gas component returning part for returning the gas component generated in the ozone decomposition part to the upstream side of the ultraviolet irradiation part or the ultraviolet irradiation part,
The apparatus for treating organic substance-containing water according to claim 8, further comprising: The pH adjusting means maintains the pH value of the water to be treated in each of the ultraviolet irradiation sections at 4.5 to 5.5, or the pH value of the water to be treated is 4.5 to 5.5. So as to adjust the amount of the pH adjuster added,
The apparatus for treating organic substance-containing water according to any one of claims 5 to 9, wherein:

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