JP2004141720A

JP2004141720A - Treatment method of waste fluid containing organic harmful substance and treatment equipment therefor

Info

Publication number: JP2004141720A
Application number: JP2002307162A
Authority: JP
Inventors: Jinichi Ito; 伊藤　仁一; Yasuaki Nishio; 西尾　康明
Original assignee: JIPCOM KK; JIPUKOMU KK
Current assignee: JIPCOM KK; JIPUKOMU KK
Priority date: 2002-10-22
Filing date: 2002-10-22
Publication date: 2004-05-20

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method which enables organic harmful substances to efficiently be decomposed and removed at a low cost when a waste fluid containing the organic harmful substances such as agricultural chemicals or the like is treated, and treatment equipment therefor. <P>SOLUTION: The waste fluid containing the organic harmful substances, to which an electrolyte comprising a chloride is added in an amount of 1-10 g/L, is supplied to an electrolytic cell 30, which has an ion permeable diaphragm between an anode and cathode and is demarcated into an anode chamber 31 and a cathode chamber 32 with the diaphragm, and electrolized under conditions of a voltage of 5-20V and a current of 20-50A. After the completion of electrolysis, the treatment liquid of the anode chamber and the treatment liquid of the cathode chamber are mixed and neutralized to be drained. The treatment liquids of both chambers are preferably mixed and neutralized to be drained after standing for a definite time. Further, waste water subjected to predetermined electrolysis to be neutralized is preferably further electrolyzed using the electrolytic cell having the diaphragm between the anode and the cathode and demarcated into the anode chamber and the cathode chamber by the diaphragm. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、農薬等の有機性有害物質を含む廃液の処理方法及び処理装置に関する。
【０００２】
【従来の技術】
近年、農業の効率化が進むなかで、例えば、田植えに用いられる稚苗、中苗等の育苗は、農協などの育苗センターで集中的に行なわれるようになり、種籾等の消毒処理に使用された農薬を含む廃液が大量に排出され、その処理が問題となっている。
【０００３】
従来より、農薬等の有害物質を含む廃液を浄化するために様々な方法が提案されており、例えば、特許文献１には、有害物質を含む廃水のｐＨを酸性側に設定すると共に食塩を添加した電解原液を、鉄電極と不溶性電極を有する電解装置に供給し、前記鉄電極を陽極、前記不溶性電極を陰極にして、第一次電解を行なった後、次いで前記陰陽両電極の極性を変換してから第二次電解を行なうことにより、マグネタイトを生成せしめ、該液中に含まれる有害物質イオンをマグネタイトに吸蔵させてフェライト化することにより、廃水中から有害物質を分離除去する方法が開示されている。
【０００４】
特許文献２には、電圧を印加した炭素材料からなる障壁層の中に被処理水を通し、電解処理する水の浄化方法が開示されている。
【０００５】
特許文献３には、排水を電気分解して該排水中の重金属を析出回収しつつ、該排水中にヒドロキシラジカル存在の下で、該排水中の難分解物質を分解処理することを特徴とする有害物質の処理方法が開示されている。
【０００６】
特許文献４には、有害有機化合物類を含有する被処理物を非プロトン性溶媒中に溶解し、電解槽に陽極側と陰極側を分ける隔膜を有する２層式電解槽もしくは３層式電解槽とし、プラスの酸化電位もしくはマイナスの還元電位による通電を行なうことによって電気化学的分解を行ない、有害有機化合物類を分解する方法が開示されている。
【０００７】
特許文献５には、農薬廃液に対してオゾンによる酸化反応と電気分解による還元反応を行ない、農薬廃液に含まれる化学物質を無機化する農薬廃液の処理方法が開示されている。
【０００８】
【特許文献１】
特公昭５５−４４７６号公報
【特許文献２】
特開平７−２４４６８号公報
【特許文献３】
特開２０００−５１８６３号公報
【特許文献４】
特開２０００−８０４８９号公報
【特許文献５】
特開２００１−３４０８８１号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、上記従来の方法では、有機性有害物質を充分に分解除去することができなかったり、処理装置のコストが高くなる等、実用化に際して改善しなければならない問題があった。
【００１０】
したがって、本発明の目的は、農薬等の有機性有害物質を含む廃液を処理する際に、該有機性有害物質を効率よく、低コストで分解除去できる処理方法及び処理装置を提供することにある。
【００１１】
【課題を解決するための手段】
上記目的を達成するため、本発明の有機性有害物質を含む廃液の処理方法の第１は、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて有機性有害物質を含む廃液を処理する方法であって、有機性有害物質を含む廃液に、塩化物からなる電解質を１〜１０ｇ／Ｌとなるように添加し、この廃液を、前記電解槽の陽極室に導入し、前記電解槽の陰極室には塩化物からなる電解質を１〜１０ｇ／Ｌ含む電解液を導入して、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で電気分解を行なった後、前記陽極室の処理液と前記陰極室の処理液とを混合して中和し、排水することを特徴とする。
【００１２】
また、本発明の有機性有害物質を含む廃液の処理方法の第２は、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて有機性有害物質を含む廃液を処理する方法であって、有機性有害物質を含む廃液に、塩化物からなる電解質を１〜１０ｇ／Ｌとなるように添加し、この廃液を、前記電解槽の陽極室及び陰極室に導入し、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で電気分解を行なった後、前記陽極室の処理液と前記陰極室の処理液とを混合して中和し、排水することを特徴とする。
【００１３】
上記第１、第２の処理方法によれば、農薬等の有機性有害物質を含む廃液に、一定量以上の塩化物からなる電解質を加えて、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて、所定の電圧、電流を付加して電気分解することにより、該有機性有害物質を効率よく分解することができ、高濃度の有機性有害物質であっても、非常に低コストで分解除去することができる。この理由は明確には分からないが、電気分解による処理液のｐＨ変化だけでなく、一定量以上の塩化物からなる電解質を加えて電気分解を行なうことによって、非常に高濃度の塩素ガス及び次亜塩素酸が発生し、これらの成分により有機性有害物質が分解されると考えられる。また、電気分解後は、陽極室の処理液（酸性）と陰極室の処理液（アルカリ性）とを混合するだけで、各処理液の中和を行なうことができるので、処理液の排出も簡単に行なうことができる。
【００１４】
また、上記第２の処理方法においては、前記中和した廃水を、前記電解槽の陽極室及び陰極室に循環供給し、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で電気分解を行なった後、前記陽極室の処理液と前記陰極室の処理液とを混合して中和し、排水することが好ましい。これによれば、有機性有害物質の分解率をより向上することができる。
【００１５】
更に、本発明の有機性有害物質を含む廃液の処理方法の第３は、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて有機性有害物質を含む廃液を処理する方法であって、有機性有害物質を含む廃液に、塩化物からなる電解質を１〜１０ｇ／Ｌとなるように添加し、この廃液を前記電解槽の陰極室に導入すると共に、前記電解槽の陽極室には、前記電解質を含む廃液を前記陰極室で電気分解した後の処理液を導入して、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で電気分解を行ない、前記陰極室及び陽極室で処理された処理液を中和して排水することを特徴とする。
【００１６】
上記第３の処理方法によれば、有機性有害物質を含む廃液を陰極室と陽極室とに順次通して電気分解を行うことにより、陰極室にてアルカリ性条件下で分解されやすい有害物質が分解され、陽極室で酸性条件下、高塩素ガス、高次亜塩素酸の存在下で更に有害物質が分解されるので、廃液中の様々な有害物質をより完全に分解することができる。
【００１７】
また、上記第１〜３の処理方法においては、前記陽極室の処理液及び前記陰極の処理液を、それぞれ貯留槽に入れて放置し、これらの処理液中に含まれる残余の有機性有害物質の分解を進行させた後、中和して排水することが好ましい。これによれば、電気分解によって生じた各処理液中に含まれる次亜塩素酸等の成分により、処理液中に残る有機性有害物質が分解されるので、有機性有害物質の分解率を更に向上することができる。
【００１８】
また、本発明の有機性有害物質を含む廃液の処理方法においては、前記のいずれか一つの方法で処理された処理液を、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて、更に電気分解した後、前記電解槽の陽極室の処理液と陰極室の処理液とを混合して中和し、排水することが好ましい。これによれば、最初の電気分解で分解されずに残った有機性有害物質や、該有機性有害物質が分解されて生じた別の有害性物質を更に分解することが可能となり、廃水をより無害化することができる。
【００１９】
一方、本発明の有機性有害物質を含む廃液の処理装置の第１は、有機性有害物質を含む廃液を貯留する廃液貯留槽と、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽と、電気分解した処理液を貯留する処理液貯留槽とを備えた有機性有害物質を含む廃液の処理装置であって、
前記廃液貯留槽から廃液を取り出し、塩化物からなる電解質を添加して、前記電解槽の陽極室に供給する手段と、
前記電解槽の陰極室に、塩化物からなる電解質を含む電解液を供給する手段と、
前記電解槽の陽極室及び陰極室から電気分解した処理液をそれぞれ取り出して前記処理液貯留槽に供給する手段と、
前記陽極室の処理液と前記陰極室の処理液とを混合し、中和して排水する手段とを備えていることを特徴とする。
【００２０】
また、本発明の有機性有害物質を含む廃液の処理装置の第２は、有機性有害物質を含む廃液を貯留する廃液貯留槽と、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽と、電気分解した処理液を貯留する処理液貯留槽とを備えた有機性有害物質を含む廃液の処理装置であって、
前記廃液貯留槽から廃液を取り出し、塩化物からなる電解質を添加して、前記電解槽の陽極室及び陰極室に供給する手段と、
前記電解槽の陽極室及び陰極室から電気分解した処理液を取り出し、前記処理液貯留槽に供給する手段と、
前記陽極室の処理液と前記陰極室の処理液とを混合し、中和すると共に、この中和された処理液を前記電解槽の陽極室及び陰極室に供給する手段と、
前記陽極室の処理液と前記陰極室の処理液とを混合し、中和して排水する手段とを備えていることを特徴とする。
【００２１】
更に、本発明の有機性有害物質を含む廃液の処理装置の第３は、有機性有害物質を含む廃液を貯留する廃液貯留槽と、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽と、電気分解した処理液を貯留する処理液貯留槽とを備えた有機性有害物質を含む廃液の処理装置であって、
前記廃液貯留槽から廃液を取り出し、塩化物からなる電解質を添加して、前記電解槽の陰極室に供給する手段と、
前記陰極室から電気分解した処理液を取り出して前記陽極室に供給する手段と、
前記電解槽の陽極室から電気分解した処理液を取り出し、前記処理液貯留槽に供給する手段と、
前記処理液を中和して排水する手段とを備えていることを特徴とする。
【００２２】
本発明の処理装置によれば、農薬等の有機性有害物を含む廃液に、一定量以上の塩化物からなる電解質を加えて、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽に供給し、所定の電圧、電流を付加して電気分解することができるので、該有機性有害物質を効率よく分解除去することができる。また、装置自体の構成が単純であり、低コストで設置することができる。
【００２３】
本発明の処理装置は、前記陽極の処理液と前記陰極の処理液とを混合して中和した廃水、あるいは前記陽極の処理液を中和した廃水を、更に電気分解するための、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を備えていることが好ましい。これによれば、最初の電気分解で分解されずに残った有機性有害物質や、該有機性有害物質が分解されて生じた別の有害性物質を更に分解することが可能となり、廃水をより無害化することができる。
【００２４】
更に、分解処理中に発生する塩素ガスを中和する手段を備えていることが好ましい。これによれば、分解処理中に発生する有害な塩素ガスが大気中に放出されるのを防ぐことができる。
【００２５】
【発明の実施の形態】
以下、図面を用いて本発明を詳細に説明する。図１は、本発明による処理装置の一実施形態を示す概略説明図である。
【００２６】
この処理装置は、有機性有害物質を含む廃液（以下、単に廃液という。）を貯留する廃液貯留槽１１と、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室３１と陰極室３２に区画された電解槽３０と、電気分解した処理液を貯留する陽極室処理液貯留槽１２、陰極室処理液貯留槽１４と、塩素ガスの除去装置４０とで主として構成されている。
【００２７】
前記電解槽３０は、図示しない、チタン基材に白金族酸化皮膜を付けたもの、又は炭素基材など連続酸化を行っても消耗しない材料からなる陽極と、ステンレス、チタン又は炭素基材からなる陰極と、それらの間に配置されたイオン透過性の隔膜とを有しており、前記隔膜によって陽極室３１と陰極室３２とに区画されている。そして、陽極と陰極とには、図示しない電源によって好ましくは５〜２０Ｖの電圧が印加されるようになっている。
【００２８】
前記廃液貯留槽１１には、ポンプ２１を介して前記電解槽３０の陽極室３１に廃液を供給するための配管が連結されており、該配管の途中には、フィルター１が設置され、更に電解液タンク１５からポンプ２３を介して塩化物からなる電解質を含む溶液（以下、電解液という。）を添加するための配管が連結されている。
【００２９】
一方、原水タンク１３には、ポンプ２２を介して前記電解槽３０の陰極室３２に井戸水又は上水を供給するための配管が連結されており、該配管の途中には、フィルター２が設置され、上記と同様に電解液タンク１５からポンプ２３を介して電解液を添加するための配管が連結されている。
【００３０】
また、前記電解槽３０の陽極室３１及び陰極室３２には、各室で電気分解した液（以下、処理液という。また、陽極室で電気分解された液を陽極室処理液、陰極室で処理された処理液を陰極室処理液という。）を取り出し、陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４にそれぞれ導入するための配管が連結されている。
【００３１】
そして、前記陽極室処理液貯留槽１２及び前記陰極室処理液貯留槽１４の上部には、各貯留槽内の処理液がオーバーフローした際に、それぞれの処理液を混合、中和して排出するための配管が連結されており、各貯留槽の下部には、バルブ５１、５２が設けられており、貯留槽内の処理液の排出口をなしている。
【００３２】
更に、前記陽極室処理液貯留槽１２には、電気分解によって発生する塩素ガスを塩素ガス中和槽４２に導入するための配管が、ファン４１を介して連結されている。
【００３３】
次に、この処理装置を用いた、本発明の有機性有害物質の処理方法について説明する。
【００３４】
まず、廃液を、廃液貯留槽１１に貯留し、通常、静置して廃液中の不溶物をできるだけ沈殿除去した後、その上澄み液をポンプ２１を介して電解槽３０の陽極室３１に供給する。このとき、前記電解槽３０とポンプ２１との間に設けられたフィルター１によって廃液に含まれる不溶物を更に除去し、また、電解液タンク１５から、ポンプ２３を介して電解液を廃液に所定量添加、混合する。上記電解液の添加量は、廃液中における塩化物からなる電解質の濃度が１〜１０ｇ／Ｌ、より好ましくは１．５〜４．５ｇ／Ｌとなるように添加する。
【００３５】
一方、原水タンク１３の井戸水又は上水を、ポンプ２２を介してフィルター２で濾過した後、電解液タンク１５から、ポンプ２３を介して電解液を所定量添加、混合してから、前記電解槽３０の陰極室３２に供給する。上記電解液の添加量は、井戸水又は上水中における塩化物からなる電解質の濃度が１〜１０ｇ／Ｌ、より好ましくは１．５〜４．５ｇ／Ｌとなるように添加する。
【００３６】
本発明における廃液としては、有機性有害物質を含む水であればよく、例えば、各種農薬、環境ホルモン物質（例えばビスフェノールＡなど）等を含む水が挙げられる。
【００３７】
また、塩化物からなる電解質としては、例えば、食塩（ＮａＣＬ）、塩化カリウム（ＫＣＬ）等が挙げられるが、コストの点から食塩が好ましく用いられる。また、塩化物からなる電解質は、水に溶解して溶液状態で添加することが好ましく、例えば、食塩の場合は、飽和食塩水（濃度約３８質量％）として添加することが好ましい。
【００３８】
そして、陽極室３１及び陰極室３２に、それぞれ上記所定の被処理液を供給しながら、電解槽３０の陽極及び陰極との間に所定の電圧を印加し、所定の電流値で電気分解を行なうと共に、電気分解が終了した処理液を陽極室及び陰極室からそれぞれ取り出し、陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４に貯留する。
【００３９】
電気分解は、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で、０．５〜８０秒間行なうことが好ましく、電圧１０〜１５Ｖ、電流２５〜３５Ａの条件で、０．５〜２０秒間行なうことがより好ましい。なお、本発明において、電気分解の処理時間は、被処理液が陽極室及び／又は陰極室に滞留する時間を意味する。
【００４０】
次いで、陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４の各処理液を、好ましくは一定時間放置した後、それぞれを混合して中和し、排水する。各処理液を貯留槽内に一定時間放置することにより、有機性有害物質の分解率を向上することができる。また、電気分解により、前記陽極室処理液は酸性、前記陰極室処理液はアルカリ性になっており、両者を混合することにより、簡単に中和することができる。
【００４１】
両処理液の混合による中和は、各貯留槽からオーバーフローした両処理液を混合して行なうことが好ましいが、各貯留槽に設けられたバルブ５１、５２を開いて、両処理液を混合、中和してもよい。
【００４２】
なお、陽極処理液には、高濃度の塩素ガスや次亜塩素酸が含まれているので、陽極処理液貯留槽１２内で発生した塩素ガスを、ファン４１を介して塩素ガス中和タンク４２に導入して中和した後、大気中に放出する。塩素ガス中和タンク４２には、例えば、石灰水が入っており、塩素ガスは、塩化カルシウムとして除去される。
【００４３】
この処理方法によれば、電気分解によって陽極室処理液のｐＨが酸性になると共に、非常に高濃度の塩素ガス及び次亜塩素酸が発生し、ｐＨ変化及びこれらの成分によって有機性有害物質が効率よく分解されると考えられる。
【００４４】
また、図２は、本発明による処理装置の別の実施形態を示す概略説明図である。なお、以下の説明において、上記実施形態と実質的に同じ構成要件には同符合を付し、その説明を省略する。
【００４５】
この処理装置は、廃液貯留槽１１と、電解槽３０と、陽極室処理液貯留槽１２、陰極室処理液貯留槽１４と、処理液を混合・中和する中和槽１６とで主として構成されている。
【００４６】
前記廃液貯留槽１１には、ポンプ２１を介して前記電解槽３０の陽極室３１及び陰極室３２に廃液を供給するための配管が連結されており、該配管の途中にはフィルター１が設置されている。更に、該配管の途中には、電解液タンク１５からポンプ２３を介して電解液を添加するための配管が連結されており、バルブ５５を切替えることにより廃液へ電解液を添加できるようになっている。
【００４７】
前記電解槽３０の陽極室３１及び陰極室３２には、陽極室処理液及び陰極室処理液を取り出し、陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４にそれぞれ導入するための配管が連結されている。
【００４８】
そして、前記陽極室処理液貯留槽１２及び前記陰極室処理液貯留槽１４の上部には、各貯留槽内の処理液がオーバーフローした際に、それぞれの処理液を中和槽１６に導入するための配管が連結されており、各貯留槽の下部には、バルブ５１、５２が設けられており、各貯留槽内の処理液を前記中和槽１６に導入するための配管が連結されている。
【００４９】
前記中和槽１６には、ポンプ２４を介して該中和槽内の処理液を前記電解槽３０の陽極室３１及び陰極室３２に供給するための配管が連結されており、バルブ５３を閉じ、バルブ５４を開くことによって、処理液を循環供給できるようになっている。そして、該配管の途中には、バルブ５５を切替えることにより、電解液タンク１５からポンプ２３を介して電解液を添加できるようになっている。また、中和槽１６には、排出口をなすバルブ５６が設けられている。
【００５０】
次に、この処理装置を用いた、本発明の有機性有害物質の処理方法について説明する。
【００５１】
まず、廃液は、廃液貯留槽１１に貯留し、上記と同様に廃液中の不溶物をできるだけ沈殿除去した後、バルブ５３を開けて、その上澄み液をポンプ２１を介して電解槽３０の陽極室３１及び陰極室３２に供給する。このとき、前記電解槽３０とポンプ２１との間に設けられたフィルター１によって廃液に含まれる不溶物を更に除去し、また、バルブ５５を切替えて、電解液タンク１５から、ポンプ２３を介して電解液を廃液に所定量添加、混合する。上記電解液の添加量は、廃液中における塩化物からなる電解質の濃度が１〜１０ｇ／Ｌ、より好ましくは１．５〜４．５ｇ／Ｌとなるように添加する。
【００５２】
そして、電解槽３０の陽極及び陰極との間に所定の電圧を印加し、所定の電流値で電気分解を行ない、電気分解が終了した処理液を、陽極室３１及び陰極室３２からそれぞれ取り出し、陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４に貯留する。
【００５３】
電気分解は、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で、０．５〜８０秒間行なうことが好ましく、電圧１０〜１５Ｖ、電流２５〜３５Ａの条件で、０．５〜２０秒間行なうことがより好ましい。
【００５４】
陽極室処理液貯留槽１２及び陰極室処理液貯留槽１４の各処理液を、好ましくは一定時間放置した後、中和槽１６において両処理液を混合、中和する。両処理液の混合による中和は、各貯留槽からオーバーフローした処理液を混合して行なうことが好ましいが、各貯留槽に設けられたバルブ５１、５２を開いて、処理液を混合、中和してもよい。
【００５５】
この処理方法においては、前記中和槽１６に貯留された処理液を、バルブ５４を開け、バルブ５３を閉じた後、ポンプ２４を介して前記電解槽３０の陽極室３１及び陰極室３２に供給し、上記と同様の条件で電気分解を行なうことが好ましい。すなわち、電気分解中に、前記バルブ５４を開け、前記バルブ５３を閉じて、前記陽極室３１及び陰極室３２に、前記中和槽１６に貯留された処理液をポンプ２４を介して供給しながら、陽極室３１及び陰極室３２からそれぞれ処理液を取り出して、中和槽１６において中和後、再び前記陽極室３１及び陰極室３２に循環供給することが好ましく、このような工程を複数回（通常、処理液が２〜４回循環する程度）行なうことがより好ましい。これにより、有機性有害物質の分解率を向上することができる。なお、上記のように処理液を循環しながら電気分解する際には、電解電流値を維持するために、必要に応じてバルブ５５を切替えて、電解液タンク１５からポンプ２３を介して所定量の電解液を処理液に添加、混合することが好ましい。この場合、上記電解液の添加量は、通常、最初に添加した量の半分程度で十分である。
【００５６】
そして、上記所定の電気分解が終了した陽極室処理液及び陰極室処理液を中和槽１６で混合、中和した後、バルブ５６を開けて排水する。
【００５７】
この処理方法によれば、電気分解によって陽極室処理液のｐＨが酸性、陰極室処理液のｐＨがアルカリ性になり、更に、陽極室では、非常に高濃度の塩素ガス及び次亜塩素酸が発生し、ｐＨ変化及びこれらの成分によって有機性有害物質が効率よく分解されると考えられる。
【００５８】
また、図３は、本発明による処理装置の更に別の実施形態を示す概略説明図である。
【００５９】
この処理装置は、廃液貯留槽１１と、電解槽３０と、処理液貯留槽１７と、処理液を希釈、中和する放流槽１８とで主として構成されている。
【００６０】
前記廃液貯留槽１１には、ポンプ２１を介して前記電解槽３０の陰極室３２に廃液を供給するための配管が連結されており、該配管の途中には、フィルター１が設置され、更に電解液タンク１５からポンプ２３を介して電解液を添加するための配管が連結されている。
【００６１】
前記電解槽３０の陰極室３２には、陰極室処理液を取り出し、陽極室３１に供給するための配管が連結されており、該配管の途中には、酸性剤タンク１９からポンプ２５を介して酸性剤を添加するための配管が連結されている。
【００６２】
また、前記電解槽３０の陽極室３１には、陽極室処理液を取り出し、処理液貯留槽１７に導入するための配管が連結されている。
【００６３】
処理液貯留槽１７の上部には、貯留槽内の処理液がオーバーフローした際に、放流槽１８に導入されるように配管が連結されており、該貯留槽の下部には、バルブ５７が設けられており、貯留槽内の処理液を前記放流槽１８に導入するための配管が連結されている。
【００６４】
前記放流槽１８には、井戸水又は上水を供給できるように配管が連結されている。また、該放流槽１８の上部にはオーバーフローによって排水するための配管が連結されており、下部にはバルブ５８が設けられており、排出口をなしている。
【００６５】
次に、この処理装置を用いた、本発明の有機性有害物質の処理方法について説明する。
【００６６】
まず、廃液は、廃液貯留槽１１に貯留し、上記と同様に廃液中の不溶物をできるだけ沈殿除去した後、バルブ５３を開けて、その上澄み液をポンプ２１を介して電解槽３０の陰極室３２に供給する。このとき、前記電解槽３０とポンプ２１との間に設けられたフィルター１によって廃液に含まれる不溶物を更に除去し、また、電解液タンク１５からポンプ２３を介して電解液を廃液に所定量添加、混合する。上記電解液の添加量は、廃液中における塩化物からなる電解質の濃度が１〜１０ｇ／Ｌ、より好ましくは１．５〜４．５ｇ／Ｌとなるように添加する。
【００６７】
一方、陽極室３１には、予め前記電解槽３０の陰極室３２で電気分解された陰極室処理液を中和してから供給する。
【００６８】
そして、陰極室３２に電解質を添加した廃液を供給すると共に該陰極室３２から陰極室処理液を取り出して、酸性剤タンク１９からポンプ２５を介して酸性剤を所定量添加して中和してから、陽極室３１に供給しながら、電解槽３０の陽極及び陰極との間に所定の電圧を印加し、所定の電流値で電気分解を行ない、陽極室３１から陽極室処理液を取り出し、処理液貯留槽１７に貯留する。電気分解は、電圧５〜２０Ｖ、電流２０〜５０Ａの条件で、０．５〜８０秒間行なうことが好ましく、電圧１０〜１５Ｖ、電流２５〜３５Ａの条件で、０．５〜２０秒間行なうことがより好ましい。
【００６９】
また、上記酸性剤としては、塩酸を用いることが好ましい。酸性剤による陰極室処理液の中和は、ｐＨ４．５〜７．５となるように行なうことが好ましく、５．５〜６．５となるように行なうことがより好ましい。
【００７０】
この処理方法においては、電解質が添加された廃液は、まず、電解槽３０の陰極室３２で電気分解された後、続いて、陽極室３１で電気分解されてから取り出される。
【００７１】
前記処理液貯留槽１７に貯留された陽極室処理液は、好ましくは一定時間放置した後、廃液貯留槽１８において、井戸水又は上水と混合、希釈、中和（ｐＨ４．５〜７．５）してから、オーバフローにより、又はバルブ５８を開いて排水する。
【００７２】
この処理方法によれば、まず、電解槽の陰極室で電気分解を行なうことで、アルカリ性条件下で分解されやすい有機性有害物質が効率よく分解され、続いて陽極室で電気分解を行なうことで、酸性条件、高塩素ガス、高次亜塩素酸の存在下で更に有機性有害物質が分解されると考えられる。なお、塩素ガスや次亜塩素酸による有機性有害物質の分解効果を考慮すると、陰極室処理液に酸性剤を添加する代わりに、陰極室へ導入する前に電解質と共に酸性剤を添加してもよい。
【００７３】
本発明の上記各処理方法によれば、廃液中の有機性有害物質のほとんどを分解することができるが、電気分解後、中和して排水された廃水（以下、中和廃水という。）中には、分解されずに残った有機性有害物質や該有機性有害物質が分解されて生じた別の有害性物質が含まれている場合があるため、より無害化するために、この中和廃水を更に電気分解してもよい。
【００７４】
図４には、上記中和廃水の処理装置の概略説明図が示されている。この処理装置は、中和廃水貯留タンク６１と、前記電解槽３０と同様の構造を有する電解槽７０と、中和槽６２とで主として構成されている。
【００７５】
前記中和廃水貯留槽６１には、ポンプ２６を介して前記電解槽７０の陽極室及び陰極室に中和廃水を供給するための配管が連結されており、該配管の途中には、活性炭フィルター３と軟水器４が設置されている。
【００７６】
前記電解槽７０には、陽極室及び陰極室で電気分解した処理液を取り出し、前記中和槽６２に導入するための配管が連結されている。
【００７７】
まず、中和廃水を、中和廃水貯留槽６１に貯留し、ポンプ２６を介して電解槽７０の陽極室及び陰極室に供給する。このとき、前記電解槽７０とポンプ２６との間に設けられた活性炭フィルター３によって中和廃水を濾過して、遊離塩素を除去する。中和廃水に含まれる残留塩素濃度が高過ぎると、電気分解する際に、電流値が装置の容量を越えてしまう場合がある。また、電解槽７０の電極（陰極）にカルシウム等が付着するのを防ぐために、軟水器４によってカルシウム及びマグネシウムイオン等を除去する。
【００７８】
そして、電解槽７０の図示しない陽極及び陰極との間に所定の電圧を印加し、所定の電流値で電気分解を行なう。電気分解は、電圧３０〜８０Ｖ、電流２０〜４０Ａの条件で、０．５〜８０秒間行なうことが好ましく、電圧５０〜６０Ｖ、電流２５〜３５Ａの条件で、０．５〜２０秒間行なうことがより好ましい。なお、中和廃水を上記活性炭フィルターで濾過する際に、中和廃水に含まれる電解質も一部除去されるので、再度電解質を添加してから電気分解を行なうことが好ましい。電解質の添加量は特に限定されないが、通常、中和廃水１Ｌに対して、０．０１〜１ｇ添加することが好ましい。
【００７９】
電気分解終了後、電解槽７０から陽極室処理液及び陰極室処理液を取り出して、中和槽６２で混合、中和した後、排水する。
【００８０】
このように、中和廃水を更に高電圧・高電流で電気分解することにより、最初の電気分解で分解することができなかった有機性有害物質や、該有機性有害物質が分解されて生じた別の有害物質を更に分解することができ、廃水をより無害化することができる。
【００８１】
【実施例】
以下、実施例を挙げて、本発明を更に詳しく説明する。
【００８２】
実施例１
表１に示す▲１▼〜▲６▼の各農薬５ｇを上水５０Ｌに添加して５分間撹拌して懸濁した後、４日間放置してそれぞれ上澄み液（約３０Ｌ）を回収し、図２に示す処理装置を用いて、表２に示す条件で電気分解を行なった。
【００８３】
【表１】

【００８４】
すなわち、上記の各上澄み液に、飽和食塩水（濃度３８質量％）を所定量添加した後、電解槽３０の陽極室３１及び陰極室３２に供給して、２０秒間電気分解を行なった。そして、電気分解後の陽極室処理液、及び陰極室処理液中の農薬濃度を高速液体クロマトグラフィー（ＨＰＬＣ）で測定し、電気分解前後のクロマトグラフのピーク面積、又はピークの高さの比により分解率を求めた。その結果を併せて表２に示す。なお、ＨＰＬＣは以下の条件で行なった。
【００８５】

【００８６】
【表２】

【００８７】
表２から、いずれの農薬も、陰極室及び／又は陽極室で非常に効率よく分解されていることが分かる。特にプロクロラズ、トリフミン、ＭＥＰ、ＭＰＰは陰極室及び陽極室の両方において８０％以上が分解されていることが分かる。なお、表２において、飽和食塩水添加量は、上澄み液１Ｌに対する飽和食塩水の添加量を表す（以下、同じ。）。
【００８８】
比較例
表１に示す▲１▼〜▲５▼の各農薬５ｇを用いて、実施例１と同様にしてそれぞれ上澄み液（約３０Ｌ）を回収し、これらの上澄み液に飽和食塩水を添加せずにそのまま、電解槽の陽極室及び陰極室に供給し、電圧６０Ｖ、電流６〜７．５Ａの条件で２０秒間電気分解を行なった。電気分解後の陽極室処理液、陰極室処理液の生成量及びｐＨを測定した結果を表３に示す。
【００８９】
【表３】

【００９０】
そして、陽極室処理液及び陰極室処理液中の農薬濃度を実施例１と同様にしてＨＰＬＣで測定して分解率を求めた。その結果を表４に示す。なお、全体の分解率（Ｄ）は、各処理液の生成量を考慮して、次式で計算した。
【００９１】
【数１】
全体の分解率（Ｄ）＝（Ｃ_１×Ｖ_１＋Ｃ_２×Ｖ_２）／Ｃ_０×（Ｖ_２＋Ｖ_１）
Ｃ_０：電気分解処理前の農薬濃度
Ｃ_１：電気分解後の陰極室処理液の農薬濃度
Ｃ_２：電気分解後の陽極室処理液の農薬濃度
Ｖ_１：電気分解後の陰極室処理液の生成量
Ｖ_２：電気分解後の陽極室処理液の生成量
【００９２】
【表４】

【００９３】
表４から、いずれの農薬も全体の分解率が低く、ほとんど分解されていないことが分かる。なお、陽極室処理液において、オキソリニック酸及びフルジオキイソニルの分解率が約５０％となっているが、逆に陰極室処理液の濃度が上昇しており、全体としてはほとんど分解されていない。
【００９４】
実施例２
ベノミルを５００ｐｐｍ含む水溶液３０Ｌを用いて、実施例１と同様にして１回目の電気分解（低電圧・高電流）を行なった（飽和食塩水添加量１８．２４ｍＬ／Ｌ、電圧１３．２Ｖ、電流２７．２Ａの条件で２０秒間電気分解した）。
【００９５】
電気分解終了後、陽極室処理液と陰極室処理液を混合、中和し、この中和液を、図４に示す中和廃水処理装置の電解槽の陽極室及び陰極室に供給し、２回目の電気分解（高電圧・高電流）を行なった（飽和食塩水添加量０．０９ｍＬ／Ｌ、電圧６０Ｖ、電流２６Ａの条件で２０秒間電気分解した）後、陽極室処理液と陰極室処理液とを混合、中和した。
【００９６】
そして、この中和廃水に含まれる成分について、ガスクロマトグラフ質量分析（ＧＣ−ＭＳ分析）を行なった。図５にトータルイオンクロマト（ＴＩＣ）及びマスクロマト（ＭＣ）の結果、図６にマススペクトルの結果を示す。
【００９７】
図５において、▲１▼は分解物全量の波動を表し、▲２▼〜▲７▼は各分子量を持つ分解生成物の波動を表す。すなわち、▲２▼〜▲７▼にピークがあれば、その分子量を持つ分解生成物が上記▲１▼のピークの中に含まれていることを示す。例えば、▲３▼はベノミルの分解生成物であるカルベンダジム（分子量１９１）、▲６▼はベノミル（分子量２９０）を表す。したがって、▲６▼にはピークが見られず、▲２▼〜▲５▼、▲７▼にピークが見られることから、ベノミルは完全に分解されて、カルベンダジムや更に分子量の小さな他の物質に分解されていることが分かる。また、図６においても同様に、カルベンダジムのピーク（Ａ）以外にも、更に分子量の小さな分解生成物のピークが多数存在していることが分かる。
【００９８】
これらの結果から、低電圧・高電流で最初の電気分解を行なった後、高電圧・高電流で２回目の電気分解を行なうことにより、ベノミルは完全に分解されて、カルベンダジムや更に分子量の小さな他の物質に分解されていることが分かる。したがって、低電圧・高電流で最初の電気分解を行なった後、更に高電圧・高電流で電気分解を行なうことにより、農薬成分をより高い割合で分解できることが分かる。なお、上記の分子量の小さな分解生成物がどのような物質であるかは明確には分からないが、例えば、ベノミルが分解されて生じたカルベンダジム以外の分解生成物やカルベンダジムが更に分解されて生じた物質であると考えられ、ベンゼン環の一部が分解していることも考えられる。
【００９９】
【発明の効果】
以上説明したように、本発明によれば、農薬等の有機性有害物質を含む廃液に、一定量以上の塩化物からなる電解質を加えて、陽極と陰極との間にイオン透過性の隔膜を有し、前記隔膜によって陽極室と陰極室に区画された電解槽を用いて、所定の電圧、電流を付加して電気分解することにより、該有機性有害物質を効率よく分解することができ、高濃度の有機性有害物質であっても、非常に低コストで分解除去することができる。また、電気分解後は、陽極室処理液と陰極室処理液とを混合するだけで、各処理液の中和を行なうことができるので、処理液の排出も簡単に行なうことができる。
【０１００】
本発明の処理方法によれば、特に、種籾の消毒処理に使用される農薬を非常に効率よく分解することができる。
【図面の簡単な説明】
【図１】本発明の処理装置の一実施形態を示す概略説明図である。
【図２】本発明の処理装置の別の実施形態を示す概略説明図である。
【図３】本発明の処理装置の更に別の実施形態を示す概略説明図である。
【図４】電気分解によって生成した農薬分解物を更に分解するための装置の概略構成図である。
【図５】ベノミルを含む水溶液を低電圧・高電流で電気分解を行ない、更に高電圧・高電流で電気分解を行なった後の処理液のトータルイオンクロマト（ＴＩＣ）及びマスクロマト（ＭＣ）の結果を示す図である。
【図６】ベノミルを含む水溶液を低電圧・高電流で電気分解を行ない、更に高電圧・高電流で電気分解を行なった後の処理液のマススペクトルを示す図である。
【符号の説明】
１、２　フィルター
３　活性炭フィルター
４　軟水器
１１　廃液貯留槽
１２　陽極室処理液貯留槽
１３　原水タンク
１４　陰極室処理液貯留槽
１５　電解液タンク
１６、６２　中和槽
１７　処理液貯留槽
１８　放流槽
１９　酸性剤タンク
２１〜２６　ポンプ
３０、７０　電解槽
３１　陽極室
３２　陰極室
４０　塩素ガス中和装置
４１　ファン
４２　塩素ガス中和槽
５１〜５７　バルブ
６１　中和廃水貯留槽[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for treating waste liquid containing organic harmful substances such as pesticides.
[0002]
[Prior art]
In recent years, as the efficiency of agriculture has progressed, for example, seedlings used in rice planting, such as seedlings and middle seedlings, have been concentrated at nursery centers such as agricultural cooperatives, and are used for disinfection of seeds and paddies. Waste liquids containing pesticides are discharged in large quantities, and their disposal is a problem.
[0003]
Conventionally, various methods have been proposed for purifying waste liquids containing harmful substances such as pesticides. For example, in Patent Document 1, the pH of wastewater containing harmful substances is set to an acidic side and salt is added. The electrolyzed solution thus obtained is supplied to an electrolysis apparatus having an iron electrode and an insoluble electrode, and the iron electrode is used as an anode, and the insoluble electrode is used as a cathode. A method for separating and removing harmful substances from wastewater by performing magnetism after performing secondary electrolysis to generate magnetite, absorbing harmful substance ions contained in the liquid into magnetite and forming ferrite, and disclosing. Have been.
[0004]
Patent Literature 2 discloses a method of purifying water in which water to be treated is passed through a barrier layer made of a carbon material to which a voltage is applied and electrolytic treatment is performed.
[0005]
Patent Literature 3 is characterized in that, while electrolyzing wastewater to precipitate and recover heavy metals in the wastewater, in the presence of hydroxy radicals in the wastewater, the hardly decomposable substances in the wastewater are decomposed. A method for treating harmful substances is disclosed.
[0006]
Patent Document 4 discloses a two-layer electrolytic cell or a three-layer electrolytic cell in which an object to be treated containing harmful organic compounds is dissolved in an aprotic solvent, and the electrolytic cell has a diaphragm that separates the anode side and the cathode side. A method of decomposing harmful organic compounds by performing an electrochemical decomposition by applying a current at a positive oxidation potential or a negative reduction potential to dissolve the harmful organic compounds is disclosed.
[0007]
Patent Literature 5 discloses a method for treating an agricultural chemical waste liquid in which an oxidation reaction with ozone and a reduction reaction by electrolysis are performed on the agricultural chemical waste liquid to mineralize chemical substances contained in the agricultural chemical waste liquid.
[0008]
[Patent Document 1]
Japanese Patent Publication No. 55-4476
[Patent Document 2]
JP-A-7-24468
[Patent Document 3]
JP 2000-51863 A
[Patent Document 4]
JP-A-2000-80489
[Patent Document 5]
JP 2001-340881 A
[0009]
[Problems to be solved by the invention]
However, the conventional methods described above have problems that must be improved in practical use, such as inability to sufficiently decompose and remove organic harmful substances and an increase in the cost of a processing apparatus.
[0010]
Therefore, an object of the present invention is to provide a processing method and a processing apparatus capable of efficiently decomposing and removing organic harmful substances at low cost when treating a waste liquid containing organic harmful substances such as pesticides. .
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a first method of treating a waste liquid containing an organic harmful substance according to the present invention includes an ion-permeable diaphragm between an anode and a cathode, and the diaphragm allows an anode chamber and a cathode chamber to be formed. A method for treating a waste liquid containing an organic harmful substance using a partitioned electrolytic tank, wherein an electrolyte made of chloride is added to the waste liquid containing an organic harmful substance so as to be 1 to 10 g / L, The waste liquid is introduced into the anode chamber of the electrolytic cell, and an electrolytic solution containing 1 to 10 g / L of an electrolyte made of chloride is introduced into the cathode chamber of the electrolytic cell. The voltage is 5 to 20 V and the current is 20 to 50 A. After the electrolysis is performed under the above conditions, the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber are mixed and neutralized, and then drained.
[0012]
A second aspect of the method for treating a waste liquid containing an organic harmful substance according to the present invention is an electrolytic cell having an ion-permeable partition between an anode and a cathode, the partition being divided into an anode chamber and a cathode chamber by the partition. A method for treating a waste liquid containing an organic harmful substance using the method described above, wherein an electrolyte made of chloride is added to the waste liquid containing the organic harmful substance at a concentration of 1 to 10 g / L, and the waste liquid is subjected to the method described above. After being introduced into the anode chamber and the cathode chamber of the electrolytic cell and performing electrolysis under the conditions of a voltage of 5 to 20 V and a current of 20 to 50 A, the processing solution of the anode chamber and the processing solution of the cathode chamber are mixed and mixed. It is characterized by humidification and drainage.
[0013]
According to the first and second treatment methods, an electrolyte composed of a certain amount or more of chloride is added to a waste liquid containing organic harmful substances such as agricultural chemicals, and an ion-permeable diaphragm is provided between the anode and the cathode. By using an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, a predetermined voltage and current are applied to perform electrolysis, whereby the organic harmful substance can be efficiently decomposed. Even high concentrations of organic harmful substances can be decomposed and removed at very low cost. Although the reason for this is not clearly understood, not only the pH change of the processing solution due to electrolysis, but also the addition of an electrolyte consisting of a certain amount of chloride or more to carry out the electrolysis leads to a very high concentration of chlorine gas and It is thought that chlorous acid is generated and these components decompose organic harmful substances. In addition, after electrolysis, each processing solution can be neutralized simply by mixing the processing solution in the anode chamber (acidic) and the processing solution in the cathode chamber (alkali), so that the processing solution can be easily discharged. Can be performed.
[0014]
In the second treatment method, the neutralized wastewater is circulated and supplied to the anode chamber and the cathode chamber of the electrolytic cell, and electrolysis is performed under the conditions of a voltage of 5 to 20 V and a current of 20 to 50 A. Preferably, the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber are mixed and neutralized, and then drained. According to this, the decomposition rate of the organic harmful substance can be further improved.
[0015]
Further, the third method of the present invention for treating a waste liquid containing an organic harmful substance includes an electrolytic cell having an ion-permeable partition between an anode and a cathode, and the partition being divided into an anode compartment and a cathode compartment by the partition. A method for treating a waste liquid containing an organic harmful substance using the method described above, wherein an electrolyte made of chloride is added to the waste liquid containing the organic harmful substance at a concentration of 1 to 10 g / L, and the waste liquid is subjected to the electrolysis. Along with being introduced into the cathode chamber of the cell, the anode chamber of the electrolytic cell was introduced with a treatment liquid obtained by electrolyzing a waste liquid containing the electrolyte in the cathode chamber, and was supplied with a voltage of 5 to 20 V and a current of 20 to 50 A. It is characterized in that electrolysis is carried out under the conditions, and the treatment solution treated in the cathode chamber and the anode chamber is neutralized and drained.
[0016]
According to the third treatment method, the waste liquid containing organic harmful substances is sequentially passed through the cathode chamber and the anode chamber to perform electrolysis, whereby harmful substances which are easily decomposed under alkaline conditions in the cathode chamber are decomposed. Since the harmful substances are further decomposed in the anode chamber under acidic conditions in the presence of high chlorine gas and high hypochlorous acid, various harmful substances in the waste liquid can be decomposed more completely.
[0017]
Further, in the first to third treatment methods, the treatment solution in the anode chamber and the treatment solution in the cathode are respectively left in storage tanks, and the remaining organic harmful substances contained in these treatment solutions are left. It is preferable to neutralize and drain the water after the decomposition of the water is advanced. According to this, the organic harmful substances remaining in the processing liquid are decomposed by components such as hypochlorous acid contained in each processing liquid generated by the electrolysis, so that the decomposition rate of the organic harmful substances is further increased. Can be improved.
[0018]
Further, in the method for treating a waste liquid containing an organic harmful substance of the present invention, the treatment liquid treated by any one of the above methods, having an ion-permeable diaphragm between an anode and a cathode, Using an electrolytic cell partitioned into an anode chamber and a cathode chamber by a diaphragm, further electrolyzing, then mixing and neutralizing the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber of the electrolytic cell, and draining. Is preferred. According to this, it is possible to further decompose the organic harmful substances remaining without being decomposed in the first electrolysis and another harmful substance generated by decomposing the organic harmful substances, thereby further reducing wastewater. Can be harmless.
[0019]
On the other hand, the first of the apparatus for treating a waste liquid containing an organic harmful substance of the present invention has a waste liquid storage tank for storing a waste liquid containing an organic harmful substance, and an ion-permeable diaphragm between an anode and a cathode. An electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, and a treatment liquid waste treatment device containing an organic harmful substance including a treatment liquid storage tank for storing an electrolyzed treatment liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying the electrolyte to the anode chamber of the electrolytic tank;
Means for supplying an electrolytic solution containing an electrolyte made of chloride to the cathode chamber of the electrolytic cell,
A means for taking out each of the electrolyzed processing liquids from the anode chamber and the cathode chamber of the electrolytic cell and supplying them to the processing liquid storage tank,
Means for mixing, treating, neutralizing and draining the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber.
[0020]
Further, the second apparatus for treating a waste liquid containing an organic harmful substance of the present invention has a waste liquid storage tank for storing a waste liquid containing an organic harmful substance, and an ion-permeable diaphragm between the anode and the cathode. An electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, and a treatment liquid waste treatment device containing an organic harmful substance including a treatment liquid storage tank for storing an electrolyzed treatment liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying the electrolyte to the anode chamber and the cathode chamber of the electrolytic tank;
Means for taking out the electrolyzed processing liquid from the anode chamber and the cathode chamber of the electrolytic cell, and supplying the processing liquid to the processing liquid storage tank;
Mixing and neutralizing the processing solution of the anode chamber and the processing solution of the cathode chamber, and supplying the neutralized processing solution to the anode chamber and the cathode chamber of the electrolytic cell,
Means for mixing, treating, neutralizing and draining the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber.
[0021]
Further, the third apparatus for treating a waste liquid containing an organic harmful substance of the present invention has a waste liquid storage tank for storing a waste liquid containing an organic harmful substance, and an ion-permeable diaphragm between the anode and the cathode. An electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, and a treatment liquid waste treatment device containing an organic harmful substance including a treatment liquid storage tank for storing an electrolyzed treatment liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying it to the cathode chamber of the electrolytic tank;
Means for taking out the electrolyzed processing solution from the cathode chamber and supplying it to the anode chamber,
Means for taking out the electrolyzed processing liquid from the anode chamber of the electrolytic cell and supplying it to the processing liquid storage tank;
Means for neutralizing and draining the treatment liquid.
[0022]
According to the treatment apparatus of the present invention, wastewater containing organic harmful substances such as agricultural chemicals, an electrolyte consisting of a certain amount or more of chloride, an ion-permeable diaphragm between the anode and the cathode, The organic harmful substance can be efficiently decomposed and removed because it can be supplied to an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm and applied with a predetermined voltage and current to perform electrolysis. Further, the configuration of the apparatus itself is simple, and the apparatus can be installed at low cost.
[0023]
The treatment apparatus of the present invention is a wastewater neutralized by mixing the treatment liquid for the anode and the treatment liquid for the cathode, or the wastewater neutralized for the treatment liquid for the anode, for further electrolysis, the anode and It is preferable that an ion permeable diaphragm is provided between the cathode and the cathode, and an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm is provided. According to this, it is possible to further decompose the organic harmful substances remaining without being decomposed in the first electrolysis and another harmful substance generated by decomposing the organic harmful substances, thereby further reducing wastewater. Can be harmless.
[0024]
Further, it is preferable that a means for neutralizing chlorine gas generated during the decomposition treatment is provided. According to this, it is possible to prevent harmful chlorine gas generated during the decomposition treatment from being released into the atmosphere.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing one embodiment of a processing apparatus according to the present invention.
[0026]
The treatment apparatus has a waste liquid storage tank 11 for storing a waste liquid containing an organic harmful substance (hereinafter, simply referred to as a waste liquid), and an ion-permeable diaphragm between an anode and a cathode. It is mainly composed of an electrolytic cell 30 partitioned into 31 and a cathode chamber 32, an anode chamber processing liquid storage tank 12 for storing an electrolyzed processing liquid, a cathode chamber processing liquid storage tank 14, and a chlorine gas removing device 40. ing.
[0027]
The electrolytic cell 30 includes an anode (not shown) made of a titanium base material provided with a platinum group oxide film, or a material such as a carbon base material which will not be consumed even after continuous oxidation, and a stainless steel, titanium or carbon base material. It has a cathode and an ion-permeable diaphragm disposed therebetween, and is partitioned into an anode chamber 31 and a cathode chamber 32 by the diaphragm. A voltage of preferably 5 to 20 V is applied to the anode and the cathode by a power supply (not shown).
[0028]
A pipe for supplying a waste liquid to the anode chamber 31 of the electrolytic tank 30 via a pump 21 is connected to the waste liquid storage tank 11, and a filter 1 is provided in the middle of the pipe, and a filter 1 is further provided. A pipe for adding a solution containing an electrolyte made of chloride (hereinafter, referred to as an electrolyte) from the liquid tank 15 via a pump 23 is connected.
[0029]
On the other hand, a pipe for supplying well water or clean water to the cathode chamber 32 of the electrolytic cell 30 via the pump 22 is connected to the raw water tank 13, and the filter 2 is provided in the middle of the pipe. In the same manner as described above, a pipe for adding an electrolyte from the electrolyte tank 15 via a pump 23 is connected.
[0030]
In the anode chamber 31 and the cathode chamber 32 of the electrolytic cell 30, a solution that has been electrolyzed in each chamber (hereinafter referred to as a processing solution. The solution that has been electrolyzed in the anode chamber is treated in the anode chamber and a cathode chamber. A pipe for taking out the processed processing solution is referred to as a cathode chamber processing solution) and introducing it to the anode chamber processing liquid storage tank 12 and the cathode chamber processing liquid storage tank 14, respectively.
[0031]
When the processing liquid in each of the storage tanks overflows above the anode chamber processing liquid storage tank 12 and the cathode chamber processing liquid storage tank 14, the respective processing liquids are mixed, neutralized, and discharged. Are connected to each other, and

valves

51 and 52 are provided at the lower part of each storage tank, and constitute a discharge port of the processing liquid in the storage tank.
[0032]
Further, a pipe for introducing chlorine gas generated by electrolysis into the chlorine gas neutralization tank 42 is connected to the anode chamber treatment liquid storage tank 12 via a fan 41.
[0033]
Next, a method for treating organic harmful substances of the present invention using this treatment apparatus will be described.
[0034]
First, the waste liquid is stored in the waste liquid storage tank 11, and is usually left still to precipitate and remove insolubles in the waste liquid as much as possible. Then, the supernatant is supplied to the anode chamber 31 of the electrolytic cell 30 via the pump 21. . At this time, the filter 1 provided between the electrolytic tank 30 and the pump 21 further removes insolubles contained in the waste liquid, and the electrolytic solution is transferred from the electrolytic tank 15 to the waste liquid via the pump 23. Add quantitatively and mix. The amount of the electrolytic solution to be added is such that the concentration of the electrolyte composed of chloride in the waste liquid is 1 to 10 g / L, more preferably 1.5 to 4.5 g / L.
[0035]
On the other hand, after the well water or clean water in the raw water tank 13 is filtered by the filter 2 through the pump 22, a predetermined amount of the electrolytic solution is added and mixed from the electrolytic solution tank 15 through the pump 23, and then the electrolytic bath is 30 to the cathode chamber 32. The electrolyte is added in such a manner that the concentration of the chloride electrolyte in the well water or the tap water is 1 to 10 g / L, more preferably 1.5 to 4.5 g / L.
[0036]
The waste liquid in the present invention may be any water containing an organic harmful substance, for example, water containing various pesticides, environmental hormone substances (for example, bisphenol A) and the like.
[0037]
Examples of the electrolyte composed of chloride include salt (NaCL) and potassium chloride (KCL). Salt is preferably used from the viewpoint of cost. Further, the electrolyte composed of chloride is preferably dissolved in water and added in a solution state. For example, in the case of salt, it is preferably added as a saturated saline solution (concentration: about 38% by mass).
[0038]
Then, a predetermined voltage is applied between the anode and the cathode of the electrolytic cell 30 while supplying the predetermined liquid to be processed to the anode chamber 31 and the cathode chamber 32, respectively, and electrolysis is performed at a predetermined current value. At the same time, the processing solution after the electrolysis is taken out from the anode chamber and the cathode chamber, respectively, and stored in the anode chamber processing liquid storage tank 12 and the cathode chamber processing liquid storage tank.
[0039]
The electrolysis is preferably performed at a voltage of 5 to 20 V and a current of 20 to 50 A for 0.5 to 80 seconds, and is preferably performed at a voltage of 10 to 15 V and a current of 25 to 35 A for 0.5 to 20 seconds. More preferred. In the present invention, the treatment time of the electrolysis means a time during which the liquid to be treated stays in the anode chamber and / or the cathode chamber.
[0040]
Next, the treatment liquids in the anode chamber treatment liquid storage tank 12 and the cathode chamber treatment liquid storage tank 14 are preferably allowed to stand for a certain period of time, then mixed, neutralized, and drained. By leaving each treatment liquid in the storage tank for a certain period of time, the decomposition rate of organic harmful substances can be improved. In addition, the electrolysis solution renders the anode chamber treatment solution acidic and the cathode room treatment solution alkaline, and can be easily neutralized by mixing the two.
[0041]
The neutralization by mixing the two processing liquids is preferably performed by mixing the two processing liquids overflowing from each storage tank. However, the

valves

51 and 52 provided in each storage tank are opened to mix the two processing liquids. It may be neutralized.
[0042]
Since the anodizing solution contains a high concentration of chlorine gas and hypochlorous acid, the chlorine gas generated in the anodizing solution storage tank 12 is supplied to the chlorine gas neutralizing tank 42 via the fan 41. And neutralized and released into the atmosphere. The chlorine gas neutralization tank 42 contains, for example, lime water, and the chlorine gas is removed as calcium chloride.
[0043]
According to this treatment method, the pH of the anode chamber treatment solution becomes acidic due to electrolysis, and very high concentrations of chlorine gas and hypochlorous acid are generated. It is considered that it is decomposed efficiently.
[0044]
FIG. 2 is a schematic explanatory view showing another embodiment of the processing apparatus according to the present invention. In the following description, components that are substantially the same as those in the above embodiment are given the same reference numerals, and description thereof is omitted.
[0045]
This processing apparatus mainly includes a waste liquid storage tank 11, an electrolytic tank 30, an anode chamber processing liquid storage tank 12, a cathode chamber processing liquid storage tank 14, and a neutralization tank 16 for mixing and neutralizing the processing liquid. ing.
[0046]
A pipe for supplying a waste liquid to the anode chamber 31 and the cathode chamber 32 of the electrolytic tank 30 via a pump 21 is connected to the waste liquid storage tank 11, and a filter 1 is provided in the middle of the pipe. ing. Further, in the middle of the pipe, a pipe for adding an electrolyte from the electrolyte tank 15 via the pump 23 is connected, and by switching the valve 55, the electrolyte can be added to the waste liquid. I have.
[0047]
In the anode chamber 31 and the cathode chamber 32 of the electrolytic cell 30, pipes for taking out the anode chamber treatment liquid and the cathode chamber treatment liquid and introducing them to the anode chamber treatment liquid storage tank 12 and the cathode chamber treatment liquid storage tank 14, respectively are provided. Are linked.
[0048]
And, when the processing liquid in each storage tank overflows above the anode chamber processing liquid storage tank 12 and the cathode chamber processing liquid storage tank 14, the respective processing liquids are introduced into the neutralization tank 16. Are connected to each other, and

valves

51 and 52 are provided below the storage tanks, and pipes for introducing the processing liquid in each storage tank to the neutralization tank 16 are connected. .
[0049]
A pipe for supplying the processing solution in the neutralization tank to the anode chamber 31 and the cathode chamber 32 of the electrolytic tank 30 via a pump 24 is connected to the neutralization tank 16, and a valve 53 is closed. By opening the valve 54, the processing liquid can be circulated and supplied. By switching the valve 55 in the middle of the pipe, the electrolyte can be added from the electrolyte tank 15 via the pump 23. The neutralization tank 16 is provided with a valve 56 serving as a discharge port.
[0050]
Next, a method for treating organic harmful substances of the present invention using this treatment apparatus will be described.
[0051]
First, the waste liquid is stored in the waste liquid storage tank 11, and after removing insolubles in the waste liquid as much as possible in the same manner as described above, the valve 53 is opened, and the supernatant is pumped through the pump 21 into the anode chamber of the electrolytic tank 30. 31 and the cathode chamber 32. At this time, the filter 1 provided between the electrolytic cell 30 and the pump 21 further removes the insolubles contained in the waste liquid, and switches the valve 55 so that the insoluble matter is removed from the electrolytic tank 15 via the pump 23. A predetermined amount of the electrolyte is added to the waste liquid and mixed. The amount of the electrolytic solution to be added is such that the concentration of the electrolyte composed of chloride in the waste liquid is 1 to 10 g / L, more preferably 1.5 to 4.5 g / L.
[0052]
Then, a predetermined voltage is applied between the anode and the cathode of the electrolytic cell 30, electrolysis is performed at a predetermined current value, and the processing solution after the electrolysis is taken out from the anode chamber 31 and the cathode chamber 32, respectively. It is stored in the anode chamber processing liquid storage tank 12 and the cathode chamber processing liquid storage tank 14.
[0053]
The electrolysis is preferably performed at a voltage of 5 to 20 V and a current of 20 to 50 A for 0.5 to 80 seconds, and is preferably performed at a voltage of 10 to 15 V and a current of 25 to 35 A for 0.5 to 20 seconds. More preferred.
[0054]
After each of the treatment liquids in the anode treatment liquid storage tank 12 and the cathode treatment liquid storage tank 14 is preferably left for a certain period of time, the two treatment liquids are mixed and neutralized in the neutralization tank 16. The neutralization by mixing the two processing liquids is preferably performed by mixing the processing liquids overflowing from each storage tank. However, the

valves

51 and 52 provided in each storage tank are opened to mix and neutralize the processing liquids. May be.
[0055]
In this processing method, the processing liquid stored in the neutralization tank 16 is supplied to the anode chamber 31 and the cathode chamber 32 of the electrolytic tank 30 via the pump 24 after the valve 54 is opened and the valve 53 is closed. Preferably, the electrolysis is performed under the same conditions as described above. That is, during the electrolysis, the valve 54 is opened, the valve 53 is closed, and the processing liquid stored in the neutralization tank 16 is supplied to the anode chamber 31 and the cathode chamber 32 via the pump 24. It is preferable that the processing liquid is taken out from each of the anode chamber 31 and the cathode chamber 32, neutralized in the neutralization tank 16, and then circulated and supplied to the anode chamber 31 and the cathode chamber 32 again. Usually, it is more preferable to carry out the treatment liquid 2 to 4 times). Thereby, the decomposition rate of the organic harmful substance can be improved. When the electrolysis is performed while circulating the processing solution as described above, the valve 55 is switched as necessary to maintain the electrolytic current value. It is preferable to add and mix the above electrolytic solution to the treatment liquid. In this case, the amount of the electrolyte solution added is usually about half the amount added initially.
[0056]
Then, the anode chamber treatment liquid and the cathode chamber treatment liquid after completion of the predetermined electrolysis are mixed and neutralized in the neutralization tank 16, and then the valve 56 is opened to drain.
[0057]
According to this treatment method, the pH of the anolyte treatment solution becomes acidic and the pH of the catholyte treatment solution becomes alkaline by electrolysis, and further, extremely high concentrations of chlorine gas and hypochlorous acid are generated in the anolyte compartment. However, it is considered that the organic harmful substances are efficiently decomposed by the pH change and these components.
[0058]
FIG. 3 is a schematic explanatory view showing still another embodiment of the processing apparatus according to the present invention.
[0059]
This processing apparatus mainly includes a waste liquid storage tank 11, an electrolytic tank 30, a processing liquid storage tank 17, and a discharge tank 18 for diluting and neutralizing the processing liquid.
[0060]
A pipe for supplying a waste liquid to the cathode chamber 32 of the electrolytic cell 30 via a pump 21 is connected to the waste liquid storage tank 11, and a filter 1 is provided in the middle of the pipe, and a filter 1 is further provided. A pipe for adding an electrolytic solution from the liquid tank 15 via a pump 23 is connected.
[0061]
The cathode chamber 32 of the electrolytic cell 30 is connected to a pipe for taking out the treatment liquid from the cathode chamber and supplying it to the anode chamber 31, and in the middle of the pipe from the acid agent tank 19 via the pump 25. A pipe for adding an acid agent is connected.
[0062]
The anode chamber 31 of the electrolytic cell 30 is connected to a pipe for taking out the processing liquid from the anode chamber and introducing it into the processing liquid storage tank 17.
[0063]
A pipe is connected to the upper part of the processing liquid storage tank 17 so as to be introduced into the discharge tank 18 when the processing liquid in the storage tank overflows, and a valve 57 is provided at the lower part of the storage tank. A pipe for introducing the processing liquid in the storage tank to the discharge tank 18 is connected.
[0064]
Piping is connected to the discharge tank 18 so that well water or clean water can be supplied. A pipe for draining water by overflow is connected to an upper part of the discharge tank 18, and a valve 58 is provided at a lower part to form a discharge port.
[0065]
Next, a method for treating organic harmful substances of the present invention using this treatment apparatus will be described.
[0066]
First, the waste liquid is stored in the waste liquid storage tank 11 and insoluble matter in the waste liquid is removed as much as possible in the same manner as described above. 32. At this time, the filter 1 provided between the electrolytic cell 30 and the pump 21 further removes insolubles contained in the waste liquid. Add and mix. The amount of the electrolytic solution to be added is such that the concentration of the electrolyte composed of chloride in the waste liquid is 1 to 10 g / L, more preferably 1.5 to 4.5 g / L.
[0067]
On the other hand, the catholyte treatment liquid electrolyzed in the cathodic compartment 32 of the electrolytic cell 30 is neutralized beforehand and supplied to the anode compartment 31.
[0068]
Then, a waste liquid to which an electrolyte is added is supplied to the cathode chamber 32, and the cathode chamber treatment liquid is taken out from the cathode chamber 32, and a predetermined amount of an acid agent is added from the acid agent tank 19 via the pump 25 to neutralize the liquid. From the anode chamber 31, a predetermined voltage is applied between the anode and the cathode of the electrolytic cell 30, electrolysis is performed at a predetermined current value, and the anode chamber treatment liquid is taken out from the anode chamber 31 and treated. The liquid is stored in the liquid storage tank 17. The electrolysis is preferably performed at a voltage of 5 to 20 V and a current of 20 to 50 A for 0.5 to 80 seconds, and is preferably performed at a voltage of 10 to 15 V and a current of 25 to 35 A for 0.5 to 20 seconds. More preferred.
[0069]
In addition, it is preferable to use hydrochloric acid as the acid agent. The neutralization of the catholyte treatment solution with the acid agent is preferably performed so as to have a pH of 4.5 to 7.5, and more preferably 5.5 to 6.5.
[0070]
In this treatment method, the waste liquid to which the electrolyte is added is firstly electrolyzed in the cathode chamber 32 of the electrolytic cell 30, and then is electrolyzed in the anode chamber 31 and then taken out.
[0071]
The anode chamber treatment liquid stored in the treatment liquid storage tank 17 is preferably left for a certain period of time, and then mixed with well water or tap water, diluted, and neutralized (pH 4.5 to 7.5) in the waste liquid storage tank 18. After that, the water is drained by overflow or by opening the valve 58.
[0072]
According to this treatment method, first, by performing electrolysis in the cathode chamber of the electrolytic cell, organic harmful substances that are easily decomposed under alkaline conditions are efficiently decomposed, and then electrolysis is performed in the anode chamber. It is considered that organic harmful substances are further decomposed in the presence of acidic conditions, high chlorine gas and high hypochlorous acid. Considering the effect of decomposing organic harmful substances by chlorine gas and hypochlorous acid, instead of adding an acid agent to the cathode chamber treatment liquid, it is also possible to add an acid agent together with the electrolyte before introducing it into the cathode chamber. Good.
[0073]
According to each of the above-mentioned treatment methods of the present invention, most of the organic harmful substances in the waste liquid can be decomposed. However, the wastewater is neutralized and discharged after electrolysis (hereinafter referred to as neutralized wastewater). May contain organic harmful substances remaining without being decomposed or other harmful substances generated by decomposing the organic harmful substances. The wastewater may be further electrolyzed.
[0074]
FIG. 4 is a schematic explanatory view of a treatment device for the neutralized wastewater. This treatment device mainly includes a neutralization wastewater storage tank 61, an electrolytic tank 70 having the same structure as the electrolytic tank 30, and a neutralization tank 62.
[0075]
A pipe for supplying neutralized wastewater to the anode chamber and the cathode chamber of the electrolytic cell 70 via a pump 26 is connected to the neutralized wastewater storage tank 61, and an activated carbon filter is provided in the middle of the pipe. 3 and a water softener 4 are installed.
[0076]
The electrolytic cell 70 is connected with a pipe for taking out the processing solution electrolyzed in the anode chamber and the cathode chamber and introducing it to the neutralization tank 62.
[0077]
First, the neutralized wastewater is stored in the neutralized wastewater storage tank 61 and supplied to the anode chamber and the cathode chamber of the electrolytic tank 70 via the pump 26. At this time, the neutralized wastewater is filtered by an activated carbon filter 3 provided between the electrolytic cell 70 and the pump 26 to remove free chlorine. If the concentration of residual chlorine contained in the neutralized wastewater is too high, the current value may exceed the capacity of the device during electrolysis. Further, in order to prevent calcium and the like from adhering to the electrode (cathode) of the electrolytic cell 70, calcium and magnesium ions and the like are removed by the water softener 4.
[0078]
Then, a predetermined voltage is applied between an anode (not shown) and a cathode (not shown) of the electrolytic cell 70 to perform electrolysis at a predetermined current value. The electrolysis is preferably performed at a voltage of 30 to 80 V and a current of 20 to 40 A for 0.5 to 80 seconds, and at a voltage of 50 to 60 V and a current of 25 to 35 A for 0.5 to 20 seconds. More preferred. When the neutralized wastewater is filtered through the activated carbon filter, the electrolyte contained in the neutralized wastewater is also partially removed. Therefore, it is preferable to perform the electrolysis after adding the electrolyte again. The amount of the electrolyte added is not particularly limited, but it is usually preferable to add 0.01 to 1 g to 1 L of the neutralized wastewater.
[0079]
After the electrolysis is completed, the anode chamber treatment liquid and the cathode chamber treatment liquid are taken out of the electrolytic cell 70, mixed and neutralized in the neutralization tank 62, and then drained.
[0080]
As described above, by further electrolyzing the neutralized wastewater at a high voltage and a high current, the organic harmful substances that could not be decomposed in the first electrolysis and the organic harmful substances were generated by being decomposed. Another harmful substance can be further decomposed, and the wastewater can be made more harmless.
[0081]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0082]
Example 1
5 g of each of the agricultural chemicals (1) to (6) shown in Table 1 was added to 50 L of tap water, stirred for 5 minutes, suspended, and allowed to stand for 4 days to recover the supernatant (about 30 L). Using the processing apparatus shown in Table 2, electrolysis was performed under the conditions shown in Table 2.
[0083]
[Table 1]

[0084]
That is, a predetermined amount of a saturated saline solution (concentration: 38% by mass) was added to each of the above supernatants, and then the solution was supplied to the anode chamber 31 and the cathode chamber 32 of the electrolytic cell 30 to perform electrolysis for 20 seconds. Then, the concentrations of the pesticides in the anolyte treatment solution and the catholyte treatment solution after the electrolysis are measured by high performance liquid chromatography (HPLC). The decomposition rate was determined. Table 2 also shows the results. The HPLC was performed under the following conditions.
[0085]

[0086]
[Table 2]

[0087]
Table 2 shows that all the pesticides were decomposed very efficiently in the cathode compartment and / or the anode compartment. In particular, it can be seen that 80% or more of prochloraz, trifumin, MEP, and MPP are decomposed in both the cathode compartment and the anode compartment. In addition, in Table 2, the addition amount of saturated saline represents the addition amount of saturated saline to 1 L of the supernatant (the same applies hereinafter).
[0088]
Comparative example
Using 5 g of each of the pesticides (1) to (5) shown in Table 1, supernatants (about 30 L) were collected in the same manner as in Example 1, and without adding saturated saline to these supernatants. As it was, it was supplied to the anode chamber and the cathode chamber of the electrolytic cell, and electrolysis was performed at a voltage of 60 V and a current of 6 to 7.5 A for 20 seconds. Table 3 shows the measurement results of the production amount and pH of the anode compartment treatment solution and the cathode compartment treatment solution after the electrolysis.
[0089]
[Table 3]

[0090]
The concentration of the pesticide in the anolyte treatment solution and the catholyte treatment solution was measured by HPLC in the same manner as in Example 1 to determine the decomposition rate. Table 4 shows the results. The overall decomposition rate (D) was calculated by the following equation in consideration of the amount of each processing solution generated.
[0091]
(Equation 1)
Total decomposition rate (D) = (C ₁ × V ₁ + C ₂ × V ₂ ) / C ₀ × (V ₂ + V ₁ )
C ₀ : Pesticide concentration before electrolysis
C ₁ : Concentration of pesticide in catholyte treatment liquid after electrolysis
C ₂ : Concentration of pesticide in anode solution after electrolysis
V ₁ ： Amount of catholyte treatment liquid generated after electrolysis
V ₂ : Amount of anolyte treatment liquid generated after electrolysis
[0092]
[Table 4]

[0093]
Table 4 shows that all the pesticides have a low overall decomposition rate and are hardly decomposed. In the anode solution, the decomposition rate of oxolinic acid and fludioxionyl is about 50%, but the concentration of the cathode solution is increased, and almost no decomposition occurs as a whole. .
[0094]
Example 2
The first electrolysis (low voltage / high current) was performed using 30 L of an aqueous solution containing 500 ppm of benomyl in the same manner as in Example 1 (addition amount of saturated saline solution 18.24 mL / L, voltage 13.2 V, current Electrolyzed at 27.2A for 20 seconds).
[0095]
After the electrolysis is completed, the anolyte treatment liquid and the catholyte treatment liquid are mixed and neutralized, and the neutralized liquid is supplied to the anode and cathode compartments of the electrolytic cell of the neutralized wastewater treatment apparatus shown in FIG. After the second electrolysis (high voltage / high current) (electrolysis was performed for 20 seconds under the conditions of a saturated saline solution addition amount of 0.09 mL / L, a voltage of 60 V, and a current of 26 A), an anode chamber treatment liquid and a cathode chamber treatment The solution was mixed and neutralized.
[0096]
Then, the components contained in the neutralized wastewater were subjected to gas chromatography mass spectrometry (GC-MS analysis). FIG. 5 shows the results of total ion chromatography (TIC) and mass chromatography (MC), and FIG. 6 shows the results of mass spectrum.
[0097]
In FIG. 5, (1) represents the wave of the total amount of the decomposition product, and (2) to (7) represent the wave of the decomposition product having each molecular weight. That is, if there is a peak in (2) to (7), it indicates that the decomposition product having the molecular weight is included in the peak in (1). For example, (3) represents carbendazim (molecular weight: 191) which is a decomposition product of benomyl, and (6) represents benomyl (molecular weight: 290). Therefore, no peak is seen in (6), but peaks are seen in (2) to (5) and (7), so that benomyl is completely decomposed to carbendazim and other substances having a smaller molecular weight. It can be seen that it has been decomposed into Also in FIG. 6, similarly, it can be seen that there are many peaks of decomposition products having a smaller molecular weight in addition to the carbendazim peak (A).
[0098]
From these results, after the first electrolysis was performed at low voltage and high current, and the second electrolysis was performed at high voltage and high current, benomyl was completely decomposed, and carbendazim and further molecular weight were reduced. It can be seen that it is broken down into other small substances. Therefore, it can be understood that the pesticide component can be decomposed at a higher ratio by performing the electrolysis at a high voltage and a high current after the first electrolysis at a low voltage and a high current. Although it is not clear what kind of substance the decomposition product having the above-mentioned low molecular weight is, for example, decomposition products other than carbendazim produced by benomyl decomposition and carbendazim are further decomposed. It is considered that the substance was generated, and a part of the benzene ring may be decomposed.
[0099]
【The invention's effect】
As described above, according to the present invention, an electrolyte composed of a certain amount or more of chloride is added to a waste liquid containing organic harmful substances such as pesticides, and an ion-permeable diaphragm is formed between the anode and the cathode. Having an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, by applying a predetermined voltage and current to perform electrolysis, the organic harmful substance can be efficiently decomposed, Even high concentrations of organic harmful substances can be decomposed and removed at very low cost. Further, after the electrolysis, each processing solution can be neutralized only by mixing the anode chamber processing solution and the cathode chamber processing solution, so that the processing solution can be easily discharged.
[0100]
According to the treatment method of the present invention, in particular, pesticides used for disinfecting seed rice can be decomposed very efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing one embodiment of a processing apparatus of the present invention.
FIG. 2 is a schematic explanatory view showing another embodiment of the processing apparatus of the present invention.
FIG. 3 is a schematic explanatory view showing still another embodiment of the processing apparatus of the present invention.
FIG. 4 is a schematic configuration diagram of an apparatus for further decomposing agrochemical decomposition products generated by electrolysis.
FIG. 5 shows the total ion chromatograph (TIC) and the mass chromatograph (MC) of the treatment liquid after electrolysis of an aqueous solution containing benomyl at low voltage and high current and further electrolysis at high voltage and high current. It is a figure showing a result.
FIG. 6 is a view showing a mass spectrum of a treatment liquid after electrolysis of an aqueous solution containing benomyl at low voltage and high current and further electrolysis at high voltage and high current.
[Explanation of symbols]
1, 2 filters
3 activated carbon filter
4 water softener
11 Waste liquid storage tank
12 Anode chamber treatment liquid storage tank
13 Raw water tank
14 Cathode chamber treatment liquid storage tank
15 Electrolyte tank
16, 62 Neutralization tank
17 Treatment liquid storage tank
18 Discharge tank
19 Acidifier tank
21-26 pump
30, 70 electrolytic cell
31 Anode room
32 cathode room
40 Chlorine gas neutralizer
41 fans
42 Chlorine gas neutralization tank
51-57 valve
61 Neutralized wastewater storage tank

Claims

A method for treating a waste liquid containing an organic harmful substance by using an electrolytic cell partitioned between an anode chamber and a cathode chamber by an ion-permeable membrane having an ion-permeable membrane between an anode and a cathode. To a waste liquid containing harmful substances, an electrolyte made of chloride is added at a concentration of 1 to 10 g / L, and this waste liquid is introduced into an anode chamber of the electrolytic cell. After introducing an electrolytic solution containing 1 to 10 g / L of the resulting electrolyte and performing electrolysis under the conditions of a voltage of 5 to 20 V and a current of 20 to 50 A, the treating solution in the anode chamber and the treating solution in the cathode chamber are mixed. A method for treating waste liquid containing organic harmful substances, wherein the waste liquid is mixed, neutralized, and drained.

A method for treating a waste liquid containing an organic harmful substance by using an electrolytic cell partitioned between an anode chamber and a cathode chamber by an ion-permeable membrane having an ion-permeable membrane between an anode and a cathode. An electrolyte made of chloride is added to the waste liquid containing the harmful substance at a concentration of 1 to 10 g / L, and the waste liquid is introduced into the anode chamber and the cathode chamber of the electrolytic cell, and the voltage is 5 to 20 V and the current is 20 to 20 g / L. A method for treating a waste liquid containing an organic harmful substance, comprising performing electrolysis under the conditions of 50 A, mixing and neutralizing the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber, and draining the mixture. .

The neutralized wastewater is circulated and supplied to the anode chamber and the cathode chamber of the electrolytic cell, and electrolysis is performed under the conditions of a voltage of 5 to 20 V and a current of 20 to 50 A. 3. The method for treating a waste liquid containing an organic harmful substance according to claim 2, wherein the liquid is neutralized by mixing with the treatment liquid of step (a), and the mixture is discharged.

A method for treating a waste liquid containing an organic harmful substance by using an electrolytic cell partitioned between an anode chamber and a cathode chamber by an ion-permeable membrane having an ion-permeable membrane between an anode and a cathode. An electrolyte made of chloride is added to the waste liquid containing the harmful substance at a concentration of 1 to 10 g / L, and the waste liquid is introduced into the cathode chamber of the electrolytic cell. The treatment liquid after electrolysis of the waste liquid containing in the cathode chamber is introduced, the electrolysis is performed under the conditions of a voltage of 5 to 20 V and a current of 20 to 50 A, and the processing liquid treated in the cathode chamber and the anode chamber is removed. A method for treating waste liquid containing organic harmful substances, characterized by neutralizing and draining.

The processing solution in the anode chamber and the processing solution in the cathode are each placed in a storage tank and allowed to stand, and after the decomposition of residual organic harmful substances contained in these processing solutions is advanced, neutralized and drained A method for treating a waste liquid containing an organic harmful substance according to any one of claims 1 to 4.

The treatment solution treated by any one of the methods of claims 1 to 5, having an ion-permeable diaphragm between the anode and the cathode, an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm. The method for treating a waste liquid containing an organic harmful substance, comprising mixing and neutralizing a treatment liquid in an anode chamber and a treatment liquid in a cathode chamber of the electrolytic cell after further electrolysis, and draining the mixture. .

A waste liquid storage tank for storing a waste liquid containing an organic harmful substance, an ion-permeable diaphragm between the anode and the cathode, and an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, A processing apparatus for waste liquid containing organic harmful substances, comprising a processing liquid storage tank for storing a processing liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying the electrolyte to the anode chamber of the electrolytic tank;
Means for supplying an electrolytic solution containing an electrolyte made of chloride to the cathode chamber of the electrolytic cell,
A means for taking out each of the electrolyzed processing liquids from the anode chamber and the cathode chamber of the electrolytic cell and supplying them to the processing liquid storage tank,
Means for mixing, neutralizing and draining the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber, and treating the waste liquid containing organic harmful substances.

A waste liquid storage tank for storing a waste liquid containing an organic harmful substance, an ion-permeable diaphragm between the anode and the cathode, and an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, A processing apparatus for waste liquid containing organic harmful substances, comprising a processing liquid storage tank for storing a processing liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying the electrolyte to the anode chamber and the cathode chamber of the electrolytic tank;
Means for taking out the electrolyzed processing liquid from the anode chamber and the cathode chamber of the electrolytic cell, and supplying the processing liquid to the processing liquid storage tank;
Mixing and neutralizing the processing solution of the anode chamber and the processing solution of the cathode chamber, and supplying the neutralized processing solution to the anode chamber and the cathode chamber of the electrolytic cell,
Means for mixing, neutralizing and draining the treatment liquid in the anode chamber and the treatment liquid in the cathode chamber, and treating the waste liquid containing organic harmful substances.

A waste liquid storage tank for storing a waste liquid containing an organic harmful substance, an ion-permeable diaphragm between the anode and the cathode, and an electrolytic cell partitioned into an anode chamber and a cathode chamber by the diaphragm, A processing apparatus for waste liquid containing organic harmful substances, comprising a processing liquid storage tank for storing a processing liquid,
Means for taking out the waste liquid from the waste liquid storage tank, adding an electrolyte made of chloride, and supplying it to the cathode chamber of the electrolytic tank;
Means for taking out the electrolyzed processing solution from the cathode chamber and supplying it to the anode chamber,
Means for taking out the electrolyzed processing liquid from the anode chamber of the electrolytic cell and supplying it to the processing liquid storage tank;
Means for neutralizing the treatment liquid and draining the same, and treating the waste liquid containing organic harmful substances.

Ion permeation between the anode and the cathode for further electrolysis of the wastewater neutralized by mixing the treatment liquid of the anode and the treatment liquid of the cathode or the wastewater neutralized of the treatment liquid of the anode. The treatment device for a waste liquid containing an organic harmful substance according to any one of claims 7 to 9, further comprising an electrolytic cell having a porous membrane, and being divided into an anode chamber and a cathode chamber by the membrane.

The apparatus for treating a waste liquid containing an organic harmful substance according to any one of claims 7 to 10, further comprising means for neutralizing chlorine gas generated during the decomposition treatment.