JP2004050085A

JP2004050085A - System for improving water quality of closed water area

Info

Publication number: JP2004050085A
Application number: JP2002212205A
Authority: JP
Inventors: Katsuyuki Fukagawa; 深川　勝之; Takashi Tanaka; 田中　喬
Original assignee: UBE KOGYO KK
Current assignee: UBE KOGYO KK
Priority date: 2002-07-22
Filing date: 2002-07-22
Publication date: 2004-02-19
Anticipated expiration: 2022-07-22
Also published as: JP3641700B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water improving system for physically/biologically treating poor oxygen water and polluted water of a closed water area to improve water quality and to expand an upper layer water area for a tap water source, and for cleaning poor oxygen water and polluted water of the dosed water area. <P>SOLUTION: There is provided a first tank 2 provided with a water pumping-up means 7 for pumping up poor oxygen water and polluted water of the closed water area as rising streams and a fine air bubble generating means 6 for forming fine air bubbles from below. There is provided a second tank 3 equipped with a floating substance removing means 9 for allowing the water to be treated flowing out of the first tank to flow as descending streams having a speed slower than the flow speed of the ascending streams of the first tank 2 to remove a floated substance and a microorganism carrier 10 provided to the descending stream flow channel. There is provided a third tank 4 equipped with a sediment accumulation means 11 for allowing the water to be treated flowing out of the second tank 3 to allow the same to flow to the upper surface of the closed water area as ascending streams to accumulate a sediment sedimented and separated from water to be treated, and also provided is a sediment removing means 14 for removing the accumulated sediment. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、湖沼、ダム湖等の閉鎖水域の貧酸素水、汚濁水域の浄化を目的とし、水道水源として用いる水域を拡大し、閉鎖水域を浄化する浄化技術に関する。
【０００２】
【従来の技術】
近年において、湖沼、ダム湖等の閉鎖水域は、流域の河川から土砂や生活排水等の汚濁物質が流入し、水中の窒素やリン等の濃度が高まる富栄養化が進み、水道水源の水並びに閉鎖水域の水の汚染が進行している。
【０００３】
汚染原因としては、水中に浮遊する流域河川等から流入した土砂等の無機物質等の増加、富栄養価に伴う微生物（代表的にはアオコ）の大量発生、貧酸素化の進行による微生物や小魚の死骸の分解物等が考えられ、これらの水中に漂う１００μｍ以下の微粒子成分を除去することにより、閉鎖水域の水質を改善することが可能であることが想定される。
【０００４】
このような汚染原因となる微粒子成分は、水中に均一に分散しているわけではなく、閉鎖水域の垂直分布における各水層によって分散している汚染源となる微粒子成分が異なる。
【０００５】
ダム湖等の閉鎖水域の垂直分布は、おおまかに、表面近傍層、上層、中層、下層、底泥等の５層に分けることができる。
【０００６】
表面近傍層は、光合成によりアオコ等の植物プランクトンが大量に発生する層である。植物プランクトンは、水中の二酸化炭素とともに、窒素やリン等を取り込み、水質の浄化を行う作用がある。しかし、アオコ等の植物プランクトンが大量発生すると、カビ臭等の異臭を発生し、更に、見た目を悪化するという問題がある。また、アオコ等の植物プランクトンは、一般に、その寿命が短いため、これらの植物プランクトンが死ぬと、表面近傍層からゆっくり沈降して上層および中層に拡散し、上層および中層で腐敗菌の発生を助長させて富栄養化を進行させ、該腐敗菌が炭酸ガスを発生して上層および中層の溶存酸素量が減少して、貧酸素化が進み、上層および中層域の水の浄化に役立つ好気性微生物、小魚等の生物の生存をおびやかす、と云う問題がある。
【０００７】
上層は、水道水源となる層であり、一定の水質が維持されている層をいうが、ダム湖等においては、年々上層の深さが極端に浅くなっていているといわれ、場所によっては、上層水が１ｍの深さしかないダム湖等もある。
【０００８】
中層は、死骸となったアオコや小魚の分解物、微生物等が沈降して浮遊する水域であり、アオコ等の死骸に発生した腐敗菌によって貧酸素化が進行している層である。また、中層には、河川流域から流入してきた微細な粘土粒子等が浮遊しており、粘土粒子等の無機物起源の粒子成分およびアオコの死骸等の有機物起源の粒子成分が滞留し、濁度（ＴＳ）が進行している層である。中層水中の無機物起源・有機物起源の粒子成分は、水中で負に帯電し、水和してコロイド粒子を形成しており、このコロイド粒子同士がお互いに反発しあって水中で安定な状態となっているため、下層域までなかなか沈降しない。
【０００９】
表面層の水温と中層の水温の差がある季節の変換期には、中層の水温が、表面層の水温よりも高いため、閉鎖水域の上下循環が行われ、空気中の酸素がダム湖表面から中層水域まで到達し、水中の溶存酸素量が増大して、水中生物の生存が脅かされることは少ない。しかし、特に、夏期においては、表面層の水温が高く、中層の水温が低くなるため、閉鎖水域の上下循環は行われず、したがって、中層水中の溶存酸素が低減し、富栄養価が進んで、中層の貧酸素化、汚濁が進行し、上層が益々浅くなる、と云う問題を生じる。
【００１０】
このように、上層水および中層水に、無機物起源、有機物起源の粒子成分が浮遊し、貧酸素水、汚濁水域が拡大している傾向にあるが、貧酸素水、汚濁水域は、上層水および中層水に限ったものではなく、ダム湖や湖沼等の閉鎖水域の水深によって貧酸素水、汚濁水域が変化する。水深が浅い閉鎖水域の底部近傍層は、後述の下層のように、嫌気状態となってはおらず、底部の方まで、無機物起源・有機物起源の粒子成分が浮遊した貧酸素水、汚濁水域が拡大した層となる場合がある。
【００１１】
下層は、水質の汚染がさらに進行している水域であり、溶存酸素が殆どなくなった嫌気的条件となっており、リン、アンモニア、メタン、硫化水素等が多量に存在している層であると考えられている。
【００１２】
底泥は、水中を沈降してきたアオコの死骸、粘土等が最終的に堆積している部分であり、大量の窒素、リン、その他河川から流入した有機物質も含んでいる。
【００１３】
このようなダム湖等の閉鎖水域の浄化技術としては、閉鎖水域を上下に循環させる手段、浮遊物を凝集させる手段、曝気による水中微生物の活性化により有機物を除去する手段、底泥を機械的に汲み上げて除去する手段等、種々の手段を用いた技術が提案されている。
【００１４】
例えば、特開平９−２５３６９８号公報にあっては、水底に向けて筒状構造体にエアリフト管を設け、酸素含有ガスを供給して水を曝気流動させながら、底泥を汲み上げ、凝集剤を添加して、凝集粒子を形成させた後、曝気を停止して懸濁粒子を水底に沈降させる底泥の処理方法が提案されている。
【００１５】
特開平９−３１４１７４号公報にあっては、深層部に配置される装置本体と、該装置本体にコンプレッサー等によって高圧エアーを供給するエアー供給手段と、装置本体内部の流速および装置本体内部等の溶存酸素濃度を測定する手段と、測定した流速と溶存酸素濃度からエアー供給量を制御する制御手段からなる深層曝気装置により、閉鎖水域の下層および底泥の溶存酸素濃度を向上させる装置が提案されている。
【００１６】
また、特開９−４７７４９号公報にあっては、閉鎖水域の少なくとも一部を仕切り装置で囲み、該仕切った被処理水域の水を取水する取水手段と、取水された被処理水と濾材を接触させて浄化して被処理水として放出する濾過槽と、該濾過槽から放出された被処理水に存在する浮遊物質を沈降させたのち、閉鎖水域に流出する沈降槽とを備えた局所水域浄化システムが提案されている。
【００１７】
【発明が解決しようとする課題】
しかしながら、前記凝集剤を添加して沈降させる底泥の処理方法にあっては、曝気流動によって、中層、下層および底泥を攪乱するため、下層および底泥中の汚染物質が、中層、さらに上層まで拡散し、一時的に上層水が汚染され、水道水源として使用することができなくなるという問題があった。また、凝集剤により、凝集させて沈降した汚染物質をそのまま底泥として堆積させているため、汚染物質の根本的な除去手段にはなっていない、と云う問題がある。
【００１８】
前記深層曝気装置にあっては、処理対象となっている下層水を曝気して、閉鎖水域の溶存酸素を増加させる技術であり、中層水および下層水中の浮遊粒子成分の根本的な除去となってはいない、と云う問題がある。また、深層曝気装置のように、コンプレッサーによって高圧状態で水中に放出される気泡は、気泡の大きさを小さくすることが困難であり、気泡は水中を上昇するに従って、外圧（水圧）が低下するため、気泡径がより大きくなり、気泡が大きくなると、単位容積中に含まれる気泡と水との接触面積が少なくなる為、水中に浮遊する微粒子成分が気泡に付着しにくい、という問題がある。
【００１９】
前記局所水域浄化システムにあっては、ダム湖等の閉鎖水域から浄水場を供給するため、ダム湖等の閉鎖水域の一部をブイを取り付けた仕切り装置で、囲んで処理する必要があり、処理作業が困難になる、と云う問題がある。また、局所水域浄化システムは、閉鎖水域の垂直分布のうち、特定の水層の浄化を目的とするものではないため、表面近傍層を浄化するための藻類用浄化装置（藻類除去装置）と、嫌気的条件（アンモニア性窒素成分）の浄化を行うための流動床式の浄化装置等、複数の装置が必要となる、という問題がある。
【００２０】
このように従来の浄化システムにあっては、閉鎖水域を、上層、中層、下層のように垂直分布に分けられる水深の深い閉鎖水域において、表面近傍層と上層、若しくは下層と底泥の浄化を目的とするものはあるものの、水道水源として用いる上層を拡大し、無機物起源、有機物起源の粒子成分が浮遊し、貧酸素水、汚濁水域が拡大している中層水の浄化に目標を絞ったものはなかった。
【００２１】
上層は水道水源として用いられる水域であるため、この上層の水域の拡大が要望されており、上層を拡大するためには、特に、水道水源として用いる上層及び中層を含む貧酸素水、汚濁水域の水質改善が要求されている。
【００２２】
従来技術のように、散気若しくは曝気により閉鎖水域の溶存酸素を増大させると、中層、下層および底泥中の汚染源となる微粒子成分を表面近傍層および上層にまで散乱させてしまうことになり、下層や底泥中のリン、アンモニア、硫化水素等が中層、上層まで攪乱されてしまう、と云う問題があった。
【００２３】
散気や曝気により上層が汚染されてしまうと、一時的に閉鎖水域の上層水を水道水源として用いることができず、公衆に多大な影響を及ぼす、と云う問題がある。
【００２４】
従って、上層、中層、下層に分けられるような水深の深い閉鎖水域にあっては、底泥、中層および下層中の汚濁物質を、上層および表面近傍層まで攪乱してしまうような浄化方法は極力避け、一時的にではあっても上層が汚染されないような浄化システムを構築すべきである。
【００２５】
更に、上層、中層、下層のように分けられない比較的浅い湖沼等の閉鎖水域においても、閉鎖水域の貧酸素水、汚濁水の原因となる種々の汚染源に着目し、各汚染源に適した手段で、総合的に種々の汚染源を分離、除去する一体的な浄化システムは構築されていなかった。
【００２６】
そこで、本発明は、叙述の諸問題を鑑みて創案されたもので、上層、中層、下層のように分けられる水深の深い閉鎖水域の上層および表面近傍層を攪乱することなく、また、比較的浅い閉鎖水域にあっても、閉鎖水域中の貧酸素水、汚濁水域の種々の汚染源に適した物理的・生物的処理を行って閉鎖水域の貧酸素水、汚濁水域の水質を改善することを技術的課題とし、もって水道水源として一定の水質維持の確保が必要となる上層を拡大することができ、貧酸素水、汚濁水域の浄化を行う閉鎖水域の水質改善システムを提供することを目的とする。
【００２７】
【課題を解決するための手段】
上記技術的課題を解決するために、
請求項１に記載した発明の手段は、閉鎖水域の貧酸素水、汚濁水域の水質を改善する、閉鎖水域の水質改善システムであること、
貧酸素水、汚濁水を上昇流として揚水する、揚水手段および下方から微細気泡を発生させる微細気泡発生手段を設けた第一槽と、該第一槽から流出した被処理水を、前記第一槽の上昇流の流速よりも遅い流速の下降流として流通して、被処理水中から浮上物及び沈降物を分離する機能を有し、浮上分離した浮上物除去手段および前記下降流の流通路に微生物担体を設けた第二槽と、該第二槽の下方から下降流として流出してきた被処理水を上昇流として閉鎖水域の上面に流出し、第二槽で沈降分離した沈降物を堆積しておく沈降物堆積手段および堆積した沈降物を除去する沈降物除去手段を設けた第三槽から成ること、にある。
【００２８】
請求項１記載の発明にあっては、揚水手段および微細気泡発生手段を設けた第一槽において、閉鎖水域の貧酸素水、汚濁水中に浮遊する、汚染原因となる無機物・有機物の浮遊微粒子を微細気泡に付着させて、上昇流として揚水する。
【００２９】
微細気泡とは、１０〜３０μｍ程度の気泡のことをいい、このような微細な気泡によって単位容積あたりの気泡の表面積を拡大して、浮遊微粒子の付着効果を増大する。
【００３０】
第一槽においては、揚水量を、微細気泡に付着できない程度の大きい粒子も上昇流として流動できる程度の量に設定し、処理対象となる貧酸素水、汚濁水中の大きい粒子も上昇流として揚水する。
【００３１】
第一槽において、微細気泡に付着して浮上してきた浮上微粒子は、第二槽において、浮上物として被処理水中から分離され、浮上物除去手段によって、除去される。浮上物除去手段としては、例えば、吸着フィルター、分離膜等を用いることが可能である。
【００３２】
第二槽では、第一槽から第二槽に流出してきた下降流が、第一槽の上昇流よりも遅い流速で流通するように設定しているため、第一槽で微細気泡に付着した微粒子を、第二槽において、確実に水面上に浮上させ、浮上物除去手段によって除去することができる。
【００３３】
また、第二槽には、微生物担体を設けているため、遅い流速でゆっくりと流れる下降流中に含まれる有機物起源の微粒子成分を、微生物担体に担持された有機物分解菌、アンモニア酸化菌、一部硝酸還元菌等の種々の微生物により生物的に分解除去する。第二槽は、第一槽から流入してきた微細気泡により、水中の溶存酸素が増大しているため、微生物が生息しやすく、微生物の活動が活発な環境となっており、微生物による有機物分解能が向上する。微生物担体としては、例えば、多孔質性の無定形炭素、ゼオライト等の多孔質性セラミック、炭素繊維等を用いた繊維質、多孔質性の合成樹脂等を用いることが可能である。
【００３４】
そして、微細気泡に付着しないような大きい粒子は、第二槽の下降流から沈降し、被処理水中から分離される。第二槽において、被処理水中から分離した沈降物は、沈降物堆積手段上に堆積させ、沈降物除去手段によって除去する。沈降物除去手段としては、例えば、沈降物を吸引して、沈降物堆積手段上から除去する吸引ポンプ等を用いることが可能である。
【００３５】
第二槽から第三槽に流入してきた被処理水は、第三槽において上昇流となって閉鎖水域に放出される。このように、被処理水は上昇流として放出されるため、清澄水となった被処理水中に沈降した大きな粒子が混入することはなく、第三槽は、整流槽としての機能を有している。
【００３６】
第一槽、第二槽および第三槽からなる水質改善システムにあっては、閉鎖水域の表面近傍層および上層を攪乱することなく、システム内完結型の処理により貧酸素水、汚濁水中の汚濁、汚染原因となる有機物起源・無機物起源の微粒子成分を、物理的および生物的手段を用いて効率的に除去して水質を改善し、溶存酸素量を増大した清澄水を、水道水源として用いる上層に放出し、上層の水域を拡大することができる。なお、上層、中層、下層のように分けることができない比較的浅い湖沼等の閉鎖水域においては、本発明のシステム内完結型の処理を行うことにより、上層水の拡大のみならず、閉鎖水域を全体的に浄化することが可能となる。
【００３７】
請求項２記載の発明の手段は、請求項１記載の発明の構成に加え、第一槽と第二槽に、第一槽から流出して第二槽に流入した被処理水の一部を再び下方から第一槽に還流する還流手段を設けたこと、にある。
【００３８】
請求項２記載の発明にあっては、第一槽と第二槽との間に還流手段を設けたため、被処理水を第二槽に繰り返し流通させて、微生物担体に担持された微生物による生物的処理に必要な滞留時間を確保することができる。
【００３９】
請求項３記載の発明の手段は、請求項１または２記載の閉鎖水域の水質改善システムにおいて、第一槽を、貧酸素水、汚濁水域まで到達する長さの内筒体とし、第二槽を、前記第一槽の外周に設け、該第一槽の壁部よりも水面上の高い位置となる壁部を備えた中筒体とし、第三槽を、前記第二槽の外周に設け、該第二槽の壁部よりも水面上で低い位置となる壁部を備えた外筒体としたこと、にある。
【００４０】
請求項３記載の発明にあっては、内筒体である第一槽において、揚水手段によって上昇流となった被処理水が、第一槽の外周に設けた第二槽にオーバーフローして、第二槽に流入し、第二槽においてオーバーフローした被処理水中から、微細気泡に付着した微粒子成分が確実に浮上分離するとともに、中筒体である第二槽で、被処理水が自然な流動によって、第一槽の上昇流よりも遅い流速の下降流となり、微生物担体間をゆっくりと流通して、被処理水中の有機物起源の微粒子成分の生物的分解処理に必要な時間を確保するとともに、被処理水中から微細気泡に付着しない大きな粒子を沈降しやすくする。
【００４１】
そして、第二槽から流出した被処理水は、第二槽の外周に設けた外筒体である第三槽にぶつかって、自然な流動によって、流速の遅い上昇流となり、沈降した粒子が被処理水中に混入することなく、第三槽から清澄化された被処理水として、閉鎖水域の上層に放出される。
【００４２】
このように、第一槽、第二槽および第三槽を、三重槽構造としたため、処理中の被処理水を外部に放出することなく、槽内完結型の水質浄化システムとして、コンパクトに設計することができ、さらに、揚水に必要な少ない稼動力で、被処理水の自然な流動を利用して、物理的・生物的処理により貧酸素水、汚濁水域の水質改善を行うことができ、稼動コストの低い、省エネルギーな水質改善システムを提供することができる。
【００４３】
請求項４記載の発明の手段は、請求項３記載の発明において、沈降物堆積手段を、第一槽の下部と第三槽の下部の間を閉塞する閉止板としたこと、にある。
【００４４】
請求項４記載の発明にあっては、沈降物堆積手段を、第一槽と第三槽の間を塞ぐ閉止板とした簡易な構造で、第二槽において分離した沈降物を、中層水、下層水に混入させることなく、除去することができる。
【００４５】
請求項５記載の発明の手段は、請求項４記載の発明において、閉止板を傾斜し、他の部位よりも低い集積部を設けたこと、にある。
【００４６】
請求項５記載の発明にあっては、沈降物堆積手段である閉止板を傾斜して、他の部位よりも低い集積部を設けたため、閉止板に堆積した沈降物が、自然に下がっている集積部に集まり、沈降物の除去が容易となる。なお、集積部は、一箇所に限らず、複数箇所設けてもよい。
【００４７】
請求項６記載の発明の手段は、請求項３、４または５記載の発明において、第二槽を、下方に従って縮径する円錐状の中筒体としたこと、にある。
【００４８】
請求項６記載の発明にあっては、第二槽を、下方に従って縮径する円錐状の中筒体としたため、第二槽は、上部ほど表面積が広くなり、第一槽から第二槽に流入した下降流の流速を遅くすることができ、また、微細気泡が浮上する面積が広くなるため、微細気泡に付着した微細粒子の浮上に有利となる。
【００４９】
また、第二槽となる中筒体は、下部ほど表面積が狭くなり、反対に第二槽の外周に設けた第三槽との間が広くなるため、第二槽から第三槽に流出した上昇流の流速を遅くして流動させることができ、大きい粒子の沈降に有利となる。
【００５０】
請求項７記載の発明の手段は、請求項１または請求項２記載の発明において、第二槽を、第一槽で揚水した被処理水が水頭圧により流通する第一槽から連続した槽とし、第三槽を、第二槽に連設した槽としたこと、にある。
【００５１】
請求項７記載の発明にあっては、第一槽、第二槽および第三槽を連続した構造とし、第一槽で揚水した被処理水を水頭圧によって流通するように構成したため、被処理水の自然な流動を利用して、稼動コストの低い、省エネルギー化を実現した水質改善システムを提供することができる。
【００５２】
請求項８記載の発明の手段は、請求項１、２、３、４、５、６または７記載の発明において、第一槽、第二槽および第三槽にフロートを設けたこと、にある。
【００５３】
請求項８記載の発明にあっては、第一槽、第二槽および第三槽を水面に浮上させるフロートを設けたため、フロートの浮力によって、ダム湖等の閉鎖水域の任意位置まで浮上移動させることができ、広範囲の閉鎖水域の貧酸素水、汚濁水域の水質改善を行うことができる。
【００５４】
【発明の実施の形態】
以下、本発明の一実施例を、図面を参照にしながら説明する。図１は、閉鎖水域の水質改善システムの概略構成を示す説明図である。図２は、閉鎖水域に水質改善システムを設置した状態をしめす説明図である。なお、図中矢印は、被処理水の流動方向を示している。
【００５５】
図１に示すように、水質改善システム１は、ダム湖等の閉鎖水域の貧酸素水、汚濁水を揚水する揚水手段である揚水装置７および下方から微細気泡を発生させる微細気泡発生手段である微細気泡発生器６とを備えた第一槽２と、該第一槽２の外周に設けた第一槽２と同心円状の中筒体である第二槽３と、該第二槽３の外周に設けた、第一槽２と同心円状の外筒体である第三槽４とから構成されている。
【００５６】
第３図は、第一槽２、第二槽３及び第三槽４の各槽における貧酸素水、汚濁水域の浄化手段を示すフロー図である。以下、第一槽２、第二槽３及び第三槽４の各槽における浄化手段を図面に基づいて順次説明する。
【００５７】
第一槽２は、貧酸素水、汚濁水域まで到達する長さを有する内筒体であり、該第一槽２に設けた揚水装置７は、モータおよび減速手段等を設けた駆動部から駆動軸を垂下設し、該駆動軸にスクリュー翼を設け、該スクリュー翼を回転駆動することにより、貧酸素水、汚濁水を上昇流として揚水する装置である。揚水装置７は、微細気泡に付着できないような、比較的大きな粒子も上昇流に乗せて浮上する揚水量となるように設定する。なお、揚水装置は、本例のものに限らず、プロペラ翼等を用いるもの、ポンプ形式によるもの等、種々の形式のものを用いることが可能である。
【００５８】
微細気泡発生器６は、均一な微細気泡（１０〜３０μｍ）を発生する装置であり、閉鎖水域水面上から空気を取り入れ微細気泡を発生する。このような微細気泡は、例えば、３０μｍの微細気泡であると、１ｍｍの大きさの気泡と比較して、表面積で３３倍、同体積では３７，０００個分となる。また、１０μｍの微細気泡であると、１ｍｍの大きさの気泡と比較して、表面積で１００倍、同体積では１，０００，０００個分となり、水中への溶解度が増大するとともに、水と接触する表面積が増えるため、浮遊微粒子を付着しやすくする。
【００５９】
微細気泡発生器６により、第一槽２の下方から微細気泡を発生させて、貧酸素水、汚濁水域に浮遊する無機物起源および有機物起源の浮遊微粒子を、微細気泡に付着させ、若しくは揚水装置７によって形成した上昇流に乗せて、第一槽２の水面近傍まで浮上させる。
【００６０】
また、微細気泡を被処理水に混入して揚水しているため、被処理水の見かけ比重が低下し、揚水装置７の駆動力を低減して、効率良く揚水を行うことができる。
【００６１】
被処理水は、第一槽２からオーバーフローして第二槽３に流入する。第二槽３は、第一槽２よりも水面上の高い位置となる壁部を備えた、中筒体である。
【００６２】
第二槽３は、第一槽２で微細気泡に付着した微細な浮遊物を浮上分離し、上昇流に乗って第一槽２を上昇してきた上昇流中の比較的重い微粒子成分を沈降分離する機能を有する。第二槽３には、浮上分離した浮遊物質を吸着除去する浮遊物除去手段９と、第二槽３の流路に微生物担体１０とを備えている。
【００６３】
浮上物除去手段９は、例えば、第二槽３の水面付近に付設した吸着フィルター又は分離膜等を用いる。第一槽２で揚水された被処理水中の微細気泡に付着した微細粒子は、第二槽３において、流速が遅くなった被処理水中から浮上し、浮上物除去手段９によって除去される。
【００６４】
第二槽３は、下方に従って縮径する円錐状の中筒体としている。本例のように、第二槽３を円錐状とするのではなく、管状の円筒体としてもよい。なお、第二槽３を円錐状の中筒体とすると、第二槽３の上部ほど表面積が拡大することとなり、第一槽２から流入してきた被処理水の流速が遅くなり、微細気泡に付着した微粒子成分の浮上分離を促進する。
【００６５】
図４の第一槽２、第二槽３及び第三槽４の平面図に示すように、第二槽３には、複数の微生物担体１０が放射状の垂下設されている。第二槽３は、第一槽２から微細気泡が混入した被処理水が流入するため、第二槽３中の溶存酸素が増大し、生物の生息に良好な環境となっている。このため、第二槽３に設けた微生物担体１０には、多数の微生物が生息し、第二槽３中をゆっくり流通する下降流中の有機物起源の粒子成分を生物的に分解処理する。
【００６６】
第二槽３を流通する下降流の流速は、第一槽２の上昇流よりも遅い流速となるように設定し、第二槽３において微生物による生物的な分解処理に必要な時間を確保する。例えば、揚水装置７の揚水量の制御や、第一槽２と第二槽３との間隔を調整する等の設計手段により、第二槽３の下降流の流速を適宜設定することが可能である。
【００６７】
また、第一槽２と第二槽３との間には、第二槽３に流れ込んできた被処理水の一部を再び第一槽２に還流する還流手段となる還流口５を設けており、微生物処理に必要な滞留時間を調整している
【００６８】
更に、第二槽３の下降流の流速を遅くすることによって、被処理水中の微細気泡に付着しないような大きな粒子の沈降を促進することができる。
【００６９】
第二槽３は、下方に従って縮径する円錐状の中筒体としたため、第二槽３の下部ほど表面積が狭くなり、反対に第二槽３の外周に配置した第三槽４の表面積が広くなるため、第二槽３の下方から第三槽４に流入した被処理水の流速が遅くなり、ゆっくりとした上昇流となって第三槽４を通流し、被処理水中から大きな粒子の沈降を促進する。
【００７０】
第三槽４と第一槽２の間には、第一槽２を中心として閉止板１１を設け、該閉止板１１は被処理水中から沈降した大きな粒子が堆積する、沈降物堆積手段として機能している。閉止板１１上に堆積した沈降物を吸引ポンプ１４等の沈降物除去手段によって定期的に除去する。閉止板１１には、左右非対称となるように、他の部位よりも低い集積部１１ａを設けている。他部位よりも下がっている集積部１１ａに、閉止板１１上に堆積した沈降物が自然に集まるため、一箇所に集められた沈降物を、簡単に吸引ポンプ１４で除去することができる。なお、図示のように、閉止板１１を左右非対称に傾斜させて、集積部１１ａを一箇所設ける場合のみならず、閉止板１１の傾斜方向を変化させることにより、集積部１１ａを複数箇所設けてもよい。
【００７１】
第一槽２に微細気泡を供給する微細気泡発生器６を、閉止板１１の下方に設ける場合は、微細気泡発生器６から発生した微細気泡が効率よく第一槽２に流入するように、閉止板１１を、第一槽２に付設する部位を上位に、第三槽４に付設する部位を下位となるように、傾斜させて設置するとよい。
【００７２】
第三槽４は、第二槽３よりも水面上の低い位置となる壁部を備えた外筒体であるため、第二槽３において下降流となって第三槽４に流入してきた被処理水は、第三槽４の壁部にぶつかって上昇流となり、第三槽４の上部からオーバーフローして、閉鎖水域の水面上に放出される。
【００７３】
第三槽４は被処理水を上昇流として流通させているため、被処理水中から沈降分離し、閉止板１１上に堆積した沈降物が巻き上げられて被処理水中に混入することはなく、整流槽として機能する。
【００７４】
水質改善システム１にあっては、第一槽２の揚水装置によって上昇流として揚水された貧酸素水、汚濁水を、第一槽２、第二槽３および第三槽４内で清澄水とする、槽内完結型のシステムとしたため、表面近傍層や上層に汚染物質を攪乱することなく、閉鎖水域の貧酸素水、汚濁水域の浄化し、水道水源として用いる上層を拡大することができる。また、上層、中層、下層のように分けられない比較的浅い湖沼等の閉鎖水域においては、閉鎖水域全体の水質改善を行うことができる。
【００７５】
第一槽２、第二槽３および第三槽４の外周には、フロート１２を設け、該フロート１２と各槽とを連結する架台１３を設けている。該フロート１２を設けることにより、水質改善システム１を、ダム湖の任意位置まで浮上移動させることができる。例えば、閉鎖水域中の任意位置の各種水質を測定し、該測定結果によって、目的とする位置まで水質改善システム１を移動させて、広範囲の閉鎖水域の貧酸素水、汚濁水域の水質改善を行うことができる。
【００７６】
水質改善システム１の第一槽２、第二槽３及び第三槽４は、同心円状の三重槽構造に限らず、図５（ａ）に示すように、楕円状の円筒体を偏心状に設けた三重槽構造としてもよく、その他図５（ｂ）に示すように、円筒体に限らず、第一槽２、第二槽３及び第三槽４を、端面矩形状の管状体の三重槽構造としてもよく、図５（ｃ）に示すように、端面矩形状の管状体を偏心状に三重槽構造としてもよい。
【００７７】
図６は、水質改善システム１の他の実施形態を示し、第一槽２を、貧酸素水、汚濁水域に到達するように、垂直方向に長い内筒体を設けている。第三槽４と第一槽２の間に設ける閉止板１１を、全体的に傾斜するように設け、自然に閉止板１１上に堆積した沈降物が、他部位よりも低い集積部１１ａに集まるようにし、吸引ポンプ１４による沈降物の除去を行いやすくしている。
【００７８】
図７は、本発明の他の実施例を示す、水質改善システム１の概略構成を示す説明図である。図７に示すように、水質改善システム１は、揚水装置７及び下方から微細気泡を発生する微細気泡発生器６を設けた第一槽２で揚水した被処理水を、流通槽３ａにオーバーフローさせ、流通槽３ａに流通させている。そして、被処理水を流通槽３ａを通じて、自然な下降流として第二槽３に流入し、第二槽３に連設した第三槽４から上昇流として閉鎖水域に流出する。
【００７９】
第一槽２と第二槽３との間には、還流手段５を設け、第二槽３には、浮上分離した浮上物分離手段９及び微生物担体１０を設けている。第三槽４には、被処理水中から沈降分離した沈降物を堆積し、他の部位よりも低い集積部１１ａを有する、第二槽３から連設した閉止板１１及び閉止板１１上に堆積し、集積部１１ａに集まった沈降物を吸引除去する吸引ポンプ１４を設けている。そして、第一槽２、第二槽３および第三槽４は、フロート１２および架台１３により水面上に支持されている。
【００８０】
図７に示すように、水質改善システム１を第一槽２、第二槽３及び第三槽４を三重槽構造とするのではなく、第一槽２から第三槽４まで連続した構造とし、槽内完結型のシステムとして、構成してもよい。
【００８１】
【発明の効果】
本発明は、上記した構成となっているので、以下に示す効果を奏する。
請求項１記載の発明にあっては、閉鎖水域の貧酸素水、汚濁水域に浮遊する、汚染原因となる無機物起源・有機物起源の微粒子を第一槽で揚水し、第二槽において、被処理水中の無機物起源の微粒子を、浮上分離、沈降分離して物理的に処理するとともに、微生物担体に担持された微生物により被処理水中の有機物起源の微粒子成分を生物的に分解処理し、第三槽から清澄水を閉鎖水域に放出する。水質改善システムは、システム内完結型の処理を行うため、表面近傍層および上層を攪乱することなく、上層の水質を維持したまま、溶存酸素量を増大した清澄水を放出して、水道水源として用いる上層水の水域を拡大し、効率的にダム湖あるいは湖沼等の閉鎖水域の水質を改善することができる。また、上層、中層、下層に分けられないような比較的浅い湖沼等の閉鎖水域においては、閉鎖水域全体の水質を改善することができる。
【００８２】
請求項２記載の発明にあっては、第一槽と第二槽との間に再び下方から第一槽に還流する還流手段を設けたため、微生物担体に担持された微生物処理に必要な滞留時間を調整することができる。
【００８３】
請求項３記載の発明にあっては、第一槽、第二槽および第三槽を、三重槽構造としたため、槽内完結型の水質改善システムとして、スペースを取らないコンパクトな設計とすることができ、かつ、少ない稼動力で省エネルギー化を実現した閉鎖水域の水質改善システムを提供することができる。
【００８４】
請求項４記載の発明にあっては、沈降物堆積手段を、第一槽と第三槽の間を塞ぐ閉止板とした簡易な構造で、第二槽において分離した沈降物を中層水や下層水中に混入させることなく、被処理水中から分離することができる。
【００８５】
請求項５記載の発明にあっては、沈降物堆積手段である閉止板を傾斜し、他の部位よりも低い集積部を設けたため、閉止板上に堆積した沈降物が、自然に下がっている集積部に集まり、集まった沈降物を簡単に除去することができる。
【００８６】
請求項６記載の発明にあっては、第二槽を下方に従って縮径する円錐状の中筒体としたため、第二槽の上部の表面積を拡大して、第一槽から第二槽に流入する被処理水の流速を遅くし、微細気泡に付着した微細粒子の浮上分離を促進するとともに、第二槽の下部の表面積を狭小として、第三槽の下部の表面積を拡大し、第二槽から第三槽に流入する被処理水の流速を遅くして、微細気泡に付着しない大きい粒子の沈降分離を促進し、浮上分離・沈降分離からなる物理的処理を効果的に行うことができる。
【００８７】
請求項７記載の発明にあっては、第一槽、第二槽および第三槽を連続した構造とし、第一槽で揚水した被処理水を水頭圧によって流通するように構成したため、被処理水の自然な流動を利用して、稼動コストの低い、省エネルギー化を実現した水質改善システムを提供することができる。
【００８８】
請求項８記載の発明にあっては、第一槽、第二槽および第三槽を水面に浮上させるフロートを設けたため、閉鎖水域の任意位置まで水質改善システムを移動させることができ、汚染度に応じて、効率良く、広範囲の閉鎖水域の貧酸素水、汚濁水域の水質改善を行うことができる。
【図面の簡単な説明】
【図１】本発明の一実施例を示す、水質改善システムの概略構成を示す説明図。
【図２】図１を閉鎖水域に設置した状態を示す説明図。
【図３】水質改善システムの浄化方法を示すフロー図。
【図４】図１に示す、水質改善システムの第一槽、第二槽、第三槽および微生物担体を示す平面図。
【図５】水質改善システムの第一槽、第二槽及び第三槽の実施例を示す説明図。
【図６】本発明の水質改善システムの他の実施形態の概略構成を示す説明図。
【図７】本発明の第二の実施例を示し、水質改善システムの概略構成を示す説明図。
【符号の説明】
１　　；　　水質改善システム
２　　；　　第一槽
３　　；　　第二槽
３ａ　；　　流通槽
４　　；　　第三槽
５　　；　　還流手段
６　　；　　微細気泡発生器
７　　；　　揚水装置
９　　；　　浮上物除去手段
１０　；　　微生物担体
１１　；　　閉止板
１１ａ；　　集積部
１２　；　　フロート
１３　；　　架台
１４　；　　吸引ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a purification technique for purifying anoxic water and polluted water in closed water areas such as lakes and marshes and dam lakes, expanding a water area used as a tap water source, and purifying the closed water area.
[0002]
[Prior art]
In recent years, in closed water areas such as lakes and marshes, dam lakes, etc., pollutants such as sediment and domestic wastewater have flowed in from rivers in the basin, and the concentration of nitrogen and phosphorus in the water has increased, and eutrophication has progressed. Water pollution in closed water areas is increasing.
[0003]
Pollution causes include an increase in inorganic substances such as sediment that flowed in from rivers and other rivers that float in water, a large amount of microorganisms (typically, algae) associated with eutrophication, and microorganisms and small It is conceivable that decomposed products of fish carcasses and the like can be considered, and it is assumed that it is possible to improve the water quality of the closed water area by removing these 100 μm or less fine particle components floating in the water.
[0004]
The fine particle components causing such contamination are not uniformly dispersed in water, and the fine particle components serving as the pollution source dispersed by each water layer in the vertical distribution of the closed water area are different.
[0005]
The vertical distribution of closed water bodies such as dam lakes can be roughly divided into five layers: near surface layer, upper layer, middle layer, lower layer, and bottom mud.
[0006]
The near-surface layer is a layer where a large amount of phytoplankton such as blue-green algae is generated by photosynthesis. Phytoplankton has an effect of purifying water quality by taking in nitrogen, phosphorus, etc. together with carbon dioxide in water. However, when a large amount of phytoplankton such as blue-green algae is generated, there is a problem that an unpleasant odor such as a moldy odor is generated, and the appearance is further deteriorated. In addition, phytoplankton such as blue-green algae generally have a short life span.When these phytoplanktons die, they slowly sink down from the near-surface layer and diffuse into the upper and middle layers, promoting the generation of spoilage bacteria in the upper and middle layers. To promote eutrophication, and the putrefactive bacteria generate carbon dioxide gas to reduce the amount of dissolved oxygen in the upper and middle layers, leading to hypoxia and aerobic microorganisms useful for purifying water in the upper and middle layers. And threatens the survival of small fish and other organisms.
[0007]
The upper layer is a layer that serves as a tap water source and refers to a layer that maintains a constant water quality.However, in dam lakes and the like, it is said that the depth of the upper layer is extremely shallow year by year. Some dam lakes have a depth of only 1m in the upper water.
[0008]
The middle layer is a body of water in which the decomposed products of dead water and small fish, microorganisms, and the like settle and float, and are anoxic due to putrefactive bacteria generated in the dead water of the water and the like. In the middle layer, fine clay particles and the like flowing from the river basin are suspended, and particles derived from inorganic substances such as clay particles and particles derived from organic substances such as carcasses of blue-green algae stay therein, and turbidity ( TS) is a layer in which advancing occurs. Particles of inorganic and organic origin in the middle layer water are negatively charged in water and hydrate to form colloidal particles.These colloidal particles repel each other and become stable in water. Therefore, it does not readily sink to the lower part.
[0009]
During the conversion period of the season when there is a difference between the surface layer water temperature and the middle layer water temperature, the middle layer water temperature is higher than the surface layer water temperature. , The dissolved oxygen content in the water increases, and the survival of the aquatic organisms is rarely threatened. However, especially in summer, the surface temperature of the surface layer is high, and the temperature of the middle layer is low, so that the vertical circulation of the closed water area is not performed.Therefore, the dissolved oxygen in the middle layer water is reduced and the eutrophication value is enhanced. The middle layer becomes deoxygenated and polluted, and the upper layer becomes increasingly shallow.
[0010]
As described above, in the upper layer water and the middle layer water, the inorganic and organic matter-derived particle components float, and the oxygen-deficient water and the polluted water area tend to expand. The oxygen-free water and polluted water area vary depending on the depth of closed water areas such as dam lakes and lakes, not limited to middle water. The near-bottom layer of the shallow closed water area is not anaerobic as the lower layer described below, and the anoxic water and polluted water area where the inorganic and organic particles are suspended to the bottom is expanded. In some cases.
[0011]
The lower layer is a water area where water pollution is further progressing, under anaerobic conditions with almost no dissolved oxygen, and a layer where phosphorus, ammonia, methane, hydrogen sulfide, etc. are present in large amounts. It is considered.
[0012]
Sediment is the part where the dead carcass and clay etc. that have settled in the water are finally deposited, and also contain a large amount of nitrogen, phosphorus, and other organic substances flowing in from the river.
[0013]
Techniques for purifying closed water areas such as dam lakes include means for circulating closed water areas up and down, means for flocculating suspended matter, means for removing organic matter by activating aquatic microorganisms by aeration, and mechanically removing sediment. Techniques using various means, such as a means for pumping and removing, have been proposed.
[0014]
For example, in Japanese Patent Application Laid-Open No. Hei 9-253,698, an air lift pipe is provided in a tubular structure toward the bottom of the water, and while supplying oxygen-containing gas and aerating and flowing the water, the bottom mud is pumped up to remove the flocculant. A method of treating bottom mud has been proposed in which aeration is stopped after addition to form aggregated particles and suspended particles settle on the water floor.
[0015]
In Japanese Patent Application Laid-Open No. 9-314174, an apparatus main body disposed in a deep portion, air supply means for supplying high-pressure air to the apparatus main body by a compressor or the like, a flow rate inside the apparatus main body, and a flow rate in the apparatus main body. A device for improving the dissolved oxygen concentration in the lower layer and bottom mud of a closed water area by means of a deep aeration device comprising a means for measuring the dissolved oxygen concentration and a control means for controlling the air supply from the measured flow rate and the dissolved oxygen concentration has been proposed. ing.
[0016]
Further, in Japanese Patent Application Laid-Open No. 9-47949, at least a part of a closed water area is surrounded by a partitioning device, and a water intake means for taking water of the partitioned water area to be treated, A local water area comprising: a filtration tank that contacts and purifies and discharges as treated water; and a sedimentation tank that setstle suspended substances present in the treated water discharged from the filtration tank and then flows out into a closed water area. Purification systems have been proposed.
[0017]
[Problems to be solved by the invention]
However, in the method of treating sediment in which the flocculant is added and settled, the middle layer, the lower layer and the bottom mud are disturbed by aeration and flow, so that the contaminants in the lower layer and the bottom mud are separated into the middle layer and the upper layer. And the upper layer water is temporarily polluted and cannot be used as a tap water source. In addition, there is a problem that the pollutant which has been coagulated and settled by the coagulant is deposited as sediment as it is, and is not a fundamental means for removing the contaminant.
[0018]
In the deep aeration device, the lower layer water to be treated is aerated, and this is a technique for increasing the dissolved oxygen in a closed water area, which is a fundamental removal of suspended particle components in the middle water and the lower water. There is no problem. Also, as in a deep aeration device, it is difficult to reduce the size of bubbles released into water under high pressure by a compressor, and the external pressure (water pressure) decreases as the bubbles rise in the water. Therefore, when the bubble diameter becomes larger and the bubbles become larger, the contact area between the bubbles contained in the unit volume and the water becomes smaller, so that there is a problem that the fine particle components floating in the water hardly adhere to the bubbles.
[0019]
In the local water purification system, in order to supply a water purification plant from a closed water area such as a dam lake, it is necessary to surround and treat a part of the closed water area such as a dam lake with a buoy-mounted partition device, There is a problem that processing work becomes difficult. Further, since the local water purification system is not intended to purify a specific water layer in the vertical distribution of the closed water area, an algae purification device (algae removal device) for purifying a layer near the surface, There is a problem that a plurality of devices such as a fluidized-bed purifier for purifying anaerobic conditions (ammoniacal nitrogen component) are required.
[0020]
As described above, in the conventional purification system, the closed water area is separated into a vertical distribution such as an upper layer, a middle layer, and a lower layer. Although there is a target, the upper layer used as a tap water source has been expanded, and inorganic and organic particulate components have been suspended, and the target has been to purify intermediate water where oxygen-poor water and polluted water areas are expanding. There was no.
[0021]
Since the upper layer is a water area used as a tap water source, expansion of this upper layer water area is demanded.In order to expand the upper layer, in particular, oxygen-free water containing the upper layer and the middle layer used as a tap water source, and polluted water areas Water quality improvement is required.
[0022]
As in the prior art, if the dissolved oxygen in the closed water area is increased by aeration or aeration, the fine particle component serving as a contamination source in the middle layer, the lower layer and the bottom mud will be scattered to the near-surface layer and the upper layer, There is a problem that phosphorus, ammonia, hydrogen sulfide, etc. in the lower layer and bottom mud are disturbed to the middle and upper layers.
[0023]
If the upper layer is contaminated by aeration or aeration, the upper layer water in the closed water area cannot be used temporarily as a tap water source, which has a problem that the public is greatly affected.
[0024]
Therefore, in a closed water area with a deep water depth that can be divided into the upper layer, the middle layer, and the lower layer, a purification method that disturbs the sediment in the bottom mud, the middle layer and the lower layer to the upper layer and the layer near the surface is minimized. Avoid this and build a purification system that will not temporarily contaminate the upper layer.
[0025]
Furthermore, even in closed water areas such as relatively shallow lakes and marshes that cannot be divided into upper, middle and lower layers, attention should be paid to various pollutants that cause anoxic water and polluted water in the closed water areas, and means suitable for each pollution source Thus, an integrated purification system for separating and removing various pollutants has not been constructed.
[0026]
Therefore, the present invention has been made in view of the above-mentioned problems, and does not disturb the upper layer and the layer near the surface, which are divided into an upper layer, a middle layer, and a lower layer. Even in shallow closed waters, it is necessary to improve the quality of oxygen-poor water and contaminated water in closed water by performing physical and biological treatment suitable for various sources of oxygen in closed water and contaminated water. The objective is to provide a water quality improvement system for closed water bodies that can expand the upper layer where it is necessary to secure a certain level of water quality as a tap water source, and that purifies hypoxic water and polluted water areas. I do.
[0027]
[Means for Solving the Problems]
In order to solve the above technical issues,
Means of the invention described in claim 1 is a closed water body water quality improvement system for improving oxygen quality of closed water area and water quality of polluted water area,
The first tank provided with pumping means and microbubble generating means for generating microbubbles from below, pumping the oxygen-deficient water and polluted water as an upward flow, It circulates as a descending flow having a flow velocity lower than the flow velocity of the ascending flow of the tank, and has a function of separating floating material and sediment from the water to be treated. A second tank provided with a microbial carrier, and the water to be treated that has flowed out as a downward flow from below the second tank flows out to the upper surface of the closed water area as an upward flow, and sediment sedimented and separated in the second tank is deposited. And a third tank provided with sediment removing means for removing the deposited sediment.
[0028]
According to the first aspect of the present invention, in the first tank provided with the pumping means and the fine bubble generating means, suspended fine particles of inorganic and organic substances causing pollution, which float in the oxygen-deficient water and polluted water in the closed water area, are removed. Attached to the fine bubbles and pumped up as an upward flow.
[0029]
Fine bubbles refer to bubbles having a size of about 10 to 30 μm. Such fine bubbles increase the surface area of the bubbles per unit volume, thereby increasing the effect of adhering floating fine particles.
[0030]
In the first tank, the pumping amount is set to such an amount that even large particles that cannot adhere to the fine bubbles can flow as an ascending flow, and large particles in the oxygen-deficient water and polluted water to be treated are also pumped as an ascending flow. I do.
[0031]
The floating fine particles which have adhered to the fine bubbles and floated in the first tank are separated from the water to be treated as floating substances in the second tank, and are removed by the floating substance removing means. As the floating substance removing means, for example, an adsorption filter, a separation membrane, or the like can be used.
[0032]
In the second tank, the downflow flowing out of the first tank to the second tank is set to flow at a lower flow rate than the ascending flow of the first tank, so it adhered to the fine bubbles in the first tank. Fine particles can be reliably floated on the water surface in the second tank, and can be removed by the floating material removing means.
[0033]
In addition, since the microbial carrier is provided in the second tank, the organic component-derived fine particle component contained in the downflow that flows slowly at a low flow rate is reduced by organic matter-decomposing bacteria, ammonia-oxidizing bacteria, It is biologically decomposed and removed by various microorganisms such as nitrate reducing bacteria. In the second tank, the dissolved oxygen in the water is increased due to the microbubbles flowing from the first tank, so microorganisms are easy to inhabit and the environment of active microorganisms is active, and the resolution of organic matter by microorganisms is low. improves. As the microorganism carrier, for example, porous amorphous carbon, a porous ceramic such as zeolite, a fibrous material using carbon fiber or the like, a porous synthetic resin, or the like can be used.
[0034]
Then, large particles that do not adhere to the fine bubbles settle down from the descending flow of the second tank and are separated from the water to be treated. In the second tank, sediment separated from the water to be treated is deposited on sediment depositing means and removed by sediment removing means. As the sediment removing means, for example, a suction pump or the like for sucking the sediment and removing the sediment from the sediment depositing means can be used.
[0035]
The water to be treated that has flowed into the third tank from the second tank is discharged into the closed water area as an ascending flow in the third tank. As described above, since the water to be treated is discharged as an ascending flow, large particles settled in the water to be treated as clarified water are not mixed, and the third tank has a function as a rectification tank. I have.
[0036]
In the water quality improvement system consisting of the first tank, the second tank, and the third tank, the contamination in the oxygen-poor water and the polluted water by the complete treatment in the system without disturbing the layer near the surface and the upper layer of the closed water area. An upper layer that uses fine water as a tap water source to improve the water quality by efficiently removing particulate matter originating from organic and inorganic substances that cause pollution and improve the water quality by using physical and biological means. And expand the upper waters. In addition, in closed water areas such as relatively shallow lakes and marshes that cannot be divided into upper layer, middle layer, lower layer, etc., not only expansion of upper layer water but also It is possible to purify the whole.
[0037]
The means of the invention described in claim 2 is the same as the structure of the invention described in claim 1, and further includes a part of the water to be treated that flows out of the first tank and flows into the second tank in the first tank and the second tank. That is, a reflux means for returning to the first tank from below is provided again.
[0038]
In the invention according to claim 2, since the reflux means is provided between the first tank and the second tank, the water to be treated is repeatedly circulated through the second tank, and the organisms by the microorganisms carried on the microorganism carrier are provided. The residence time required for a proper treatment can be secured.
[0039]
According to a third aspect of the present invention, in the water quality improvement system for a closed water area according to the first or second aspect, the first tank is an inner cylinder having a length reaching the oxygen-deficient water and the polluted water area, and the second tank is provided. Is provided on the outer periphery of the first tank, a middle cylindrical body having a wall portion that is higher on the water surface than the wall portion of the first tank, and a third tank is provided on the outer periphery of the second tank. And an outer cylinder having a wall portion which is lower on the water surface than the wall portion of the second tank.
[0040]
In the invention according to claim 3, in the first tank that is the inner cylindrical body, the water to be treated, which has been raised by the water pumping means, overflows into the second tank provided on the outer periphery of the first tank. The fine particles adhering to the microbubbles are reliably floated and separated from the water to be treated flowing into the second tank and overflowing in the second tank, and the water to be treated flows naturally in the second tank, which is a middle cylindrical body. By this, it becomes a descending flow with a slower flow velocity than the ascending flow of the first tank, slowly circulates between the microbial carriers, and secures the time required for the biological decomposition treatment of the organic matter-derived fine particle components in the water to be treated, Large particles that do not adhere to the fine bubbles are easily settled out of the water to be treated.
[0041]
The water to be treated that has flowed out of the second tank collides with the third tank, which is an outer cylinder provided on the outer periphery of the second tank, and becomes a rising flow with a slow flow velocity due to natural flow, and the sedimented particles are covered. It is discharged into the upper layer of the closed water area as clarified water to be treated from the third tank without being mixed into the treated water.
[0042]
As described above, the first, second and third tanks have a triple tank structure, so that the water to be treated during treatment is not discharged to the outside, and a compact water purifying system is designed as a complete type in the tank. In addition, it is possible to improve the quality of oxygen-poor water and polluted water by physical and biological treatment using the natural flow of the water to be treated, with the low operating power required for pumping, An energy-saving water quality improvement system with low operation costs can be provided.
[0043]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the sediment depositing means is a closing plate for closing a space between a lower portion of the first tank and a lower portion of the third tank.
[0044]
In the invention according to claim 4, the sediment sedimentation means is a simple structure having a closing plate closing the space between the first tank and the third tank, and the sediment separated in the second tank is separated into middle water, It can be removed without mixing into the lower layer water.
[0045]
According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the closing plate is inclined to provide an accumulation portion lower than other portions.
[0046]
According to the fifth aspect of the present invention, since the closing plate, which is the sediment depositing means, is inclined to provide an accumulation portion lower than other portions, the sediment deposited on the closing plate falls naturally. It gathers at the accumulation part and the sediment is easily removed. Note that the accumulation unit is not limited to one location, and may be provided at a plurality of locations.
[0047]
According to a sixth aspect of the present invention, in the third, fourth or fifth aspect of the present invention, the second tank is a conical middle cylinder whose diameter is reduced downward.
[0048]
In the invention according to claim 6, since the second tank is a conical middle cylindrical body whose diameter is reduced downward, the surface area of the second tank increases toward the upper portion, and the second tank changes from the first tank to the second tank. The flow velocity of the inflowing downflow can be reduced, and the area in which the fine bubbles float is increased, which is advantageous for floating the fine particles attached to the fine bubbles.
[0049]
In addition, the middle cylindrical body serving as the second tank has a smaller surface area toward the lower part, and conversely, the space between the third tank provided on the outer periphery of the second tank is wider, so that the middle tank body flows out of the second tank to the third tank. The ascending flow can be made to flow at a low flow rate, which is advantageous for the settling of large particles.
[0050]
According to a seventh aspect of the present invention, in the first or second aspect of the invention, the second tank is a tank continuous from the first tank in which the water to be treated pumped in the first tank flows by the head pressure. And the third tank is a tank connected to the second tank.
[0051]
In the invention according to claim 7, the first tank, the second tank, and the third tank have a continuous structure, and the water to be treated pumped in the first tank is configured to flow by the head pressure. By using the natural flow of water, it is possible to provide a water quality improvement system that achieves low energy consumption and low operating costs.
[0052]
The means of the invention described in claim 8 is that, in the invention described in claim 1, 2, 3, 4, 5, 6, or 7, a float is provided in the first tank, the second tank, and the third tank. .
[0053]
In the invention according to claim 8, since the float for floating the first tank, the second tank and the third tank on the water surface is provided, the float is moved to an arbitrary position in a closed water area such as a dam lake by the buoyancy of the float. It can improve the quality of oxygen-deficient water and polluted water in a wide range of closed water areas.
[0054]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a water quality improvement system for a closed water area. FIG. 2 is an explanatory diagram showing a state in which a water quality improvement system is installed in a closed water area. In addition, the arrow in the figure has shown the flow direction of the to-be-processed water.
[0055]
As shown in FIG. 1, the water quality improvement system 1 is a pumping device 7 that is a pumping unit that pumps deoxygenated water and polluted water in a closed water area such as a dam lake, and a microbubble generating unit that generates microbubbles from below. A first tank 2 provided with a microbubble generator 6, a second tank 3 which is a concentric middle cylinder with the first tank 2 provided on the outer periphery of the first tank 2, It comprises a first tank 2 and a third tank 4, which is a concentric outer cylinder, provided on the outer periphery.
[0056]
FIG. 3 is a flow chart showing a means for purifying oxygen-deficient water and polluted water areas in each of the first tank 2, the second tank 3, and the third tank 4. Hereinafter, the purifying means in each of the first tank 2, the second tank 3, and the third tank 4 will be sequentially described with reference to the drawings.
[0057]
The first tank 2 is an inner cylinder having a length reaching the oxygen-deficient water and the polluted water area, and the water pumping device 7 provided in the first tank 2 is driven by a drive unit provided with a motor, a deceleration unit, and the like. A device in which a shaft is suspended, a screw blade is provided on the drive shaft, and the screw blade is driven to rotate, thereby pumping poor oxygen water and polluted water as upward flow. The pumping device 7 is set so that a relatively large particle that cannot be attached to the fine bubble has a pumping amount that floats on the upward flow. Note that the pumping device is not limited to the pumping device of this example, and various pumping devices such as a device using a propeller blade or the like and a pumping device can be used.
[0058]
The fine bubble generator 6 is a device that generates uniform fine bubbles (10 to 30 μm), and takes in air from the surface of a closed water area to generate fine bubbles. Such microbubbles are, for example, 30 μm microbubbles, 33 times as large in surface area and 37,000 in the same volume, compared to 1 mm size bubbles. In addition, when the microbubbles are 10 μm in size, the surface area is 100 times as large as the bubbles having a size of 1 mm, and the volume becomes 1,000,000 for the same volume. Since the surface area to be increased increases, the floating fine particles are easily attached.
[0059]
The microbubble generator 6 generates microbubbles from below the first tank 2, and attaches fine particles of anoxic water and inorganic and organic substances floating in the polluted water area to the microbubbles, or a pumping device 7. The first tank 2 is floated near the water surface of the first tank 2 on the upward flow formed by the above.
[0060]
In addition, since the fine bubbles are mixed with the water to be treated and the water is pumped, the apparent specific gravity of the water to be treated is reduced, the driving force of the water pumping device 7 is reduced, and the water can be pumped efficiently.
[0061]
The water to be treated overflows from the first tank 2 and flows into the second tank 3. The second tank 3 is a middle cylinder having a wall portion that is higher than the first tank 2 on the water surface.
[0062]
The second tank 3 floats and separates fine suspended matter adhering to the fine bubbles in the first tank 2, and sediments and separates relatively heavy particulate components in the upward flow that has risen in the first tank 2 by riding on the upward flow. It has a function to do. The second tank 3 is provided with a suspended matter removing means 9 for adsorbing and removing floating substances separated by flotation, and a microorganism carrier 10 in a flow path of the second tank 3.
[0063]
As the floating object removing means 9, for example, an adsorption filter or a separation membrane provided near the water surface of the second tank 3 is used. The fine particles adhering to the microbubbles in the water to be treated pumped in the first tank 2 float in the second tank 3 from the water to be treated having a reduced flow velocity, and are removed by the floating object removing means 9.
[0064]
The second tank 3 is a conical middle cylindrical body whose diameter is reduced downward. Instead of making the second tank 3 conical as in this example, it may be a tubular cylinder. When the second tank 3 is formed as a conical middle cylinder, the surface area increases as the upper part of the second tank 3 flows, and the flow rate of the water to be treated flowing from the first tank 2 decreases, and fine bubbles are formed. Flotation of attached fine particle components is promoted.
[0065]
As shown in the plan view of the first tank 2, the second tank 3 and the third tank 4 in FIG. 4, a plurality of microorganism carriers 10 are provided in the second tank 3 in a radial manner. Since the water to be treated mixed with the fine bubbles flows into the second tank 3 from the first tank 2, the dissolved oxygen in the second tank 3 is increased, and the second tank 3 has a favorable environment for living organisms. For this reason, a large number of microorganisms inhabit the microorganism carrier 10 provided in the second tank 3, and biologically decompose the organic-originated particle components in the downward flow slowly flowing through the second tank 3.
[0066]
The flow velocity of the downward flow flowing through the second tank 3 is set to be lower than the upward flow of the first tank 2, and the time required for the biological decomposition treatment by microorganisms in the second tank 3 is secured. . For example, the flow rate of the downward flow in the second tank 3 can be appropriately set by controlling the pumping amount of the water pumping device 7 or adjusting the interval between the first tank 2 and the second tank 3. is there.
[0067]
In addition, between the first tank 2 and the second tank 3, there is provided a reflux port 5 serving as a reflux means for returning a part of the water to be treated flowing into the second tank 3 to the first tank 2 again. And adjusts the residence time required for microbial treatment
[0068]
Further, by lowering the flow velocity of the descending flow in the second tank 3, sedimentation of large particles that do not adhere to fine bubbles in the water to be treated can be promoted.
[0069]
Since the second tank 3 was formed as a conical middle cylindrical body whose diameter decreased in the downward direction, the surface area became smaller toward the lower part of the second tank 3, and conversely, the surface area of the third tank 4 arranged on the outer periphery of the second tank 3 became smaller. Since the water is widened, the flow rate of the water to be treated flowing into the third tank 4 from below the second tank 3 is slowed down, and a slow upward flow flows through the third tank 4 to remove large particles from the water to be treated. Promotes settling.
[0070]
A closing plate 11 is provided between the third tank 4 and the first tank 2 around the first tank 2, and the closing plate 11 functions as sediment depositing means for depositing large particles settled from the water to be treated. are doing. The sediment deposited on the closing plate 11 is periodically removed by a sediment removing means such as the suction pump 14. The closing plate 11 is provided with an accumulation portion 11a lower than other portions so as to be asymmetrical in the left-right direction. Since the sediment deposited on the closing plate 11 naturally collects in the accumulation part 11a lower than the other part, the sediment collected in one place can be easily removed by the suction pump 14. As shown in the drawing, not only is the closing plate 11 inclined asymmetrically in the left and right direction and the stacking portion 11a is provided in one place, but also the stacking portion 11a is provided in a plurality of places by changing the inclination direction of the closing plate 11. Is also good.
[0071]
When the fine bubble generator 6 for supplying fine bubbles to the first tank 2 is provided below the closing plate 11, the fine bubbles generated from the fine bubble generator 6 flow into the first tank 2 efficiently. The closing plate 11 may be installed at an angle so that the portion attached to the first tank 2 is at the top and the portion attached to the third tank 4 is at the bottom.
[0072]
Since the third tank 4 is an outer cylindrical body having a wall located at a lower position on the surface of the water than the second tank 3, the third tank 4 flows down into the third tank 4 as a downward flow in the second tank 3. The treated water collides with the wall of the third tank 4 to form an ascending flow, overflows from the upper part of the third tank 4, and is discharged onto the surface of the closed water area.
[0073]
Since the third tank 4 circulates the water to be treated as an upward flow, it sediments and separates from the water to be treated, and the sediment deposited on the closing plate 11 is not wound up and mixed into the water to be treated. Functions as a tank.
[0074]
In the water quality improvement system 1, the oxygen-deficient water and the polluted water pumped up by the pumping device of the first tank 2 as upflow are combined with the clarified water in the first tank 2, the second tank 3, and the third tank 4. Because the system is a complete type in a tank, it is possible to purify anoxic water and polluted water in closed water areas and expand the upper layer used as a tap water source without disturbing contaminants in a layer near the surface or an upper layer. Further, in a closed water area such as a relatively shallow lake which is not divided into an upper layer, a middle layer, and a lower layer, the water quality of the entire closed water area can be improved.
[0075]
A float 12 is provided on the outer periphery of the first tank 2, the second tank 3, and the third tank 4, and a gantry 13 for connecting the float 12 and each tank is provided. By providing the float 12, the water quality improvement system 1 can be floated and moved to an arbitrary position on the dam lake. For example, various water qualities at an arbitrary position in a closed water area are measured, and the water quality improvement system 1 is moved to a target position according to the measurement result to improve the water quality of anoxic water and a polluted water area in a wide range of the closed water area. be able to.
[0076]
The first tank 2, the second tank 3, and the third tank 4 of the water quality improvement system 1 are not limited to the concentric triple tank structure, and as shown in FIG. A triple tank structure may be provided. In addition, as shown in FIG. 5B, the first tank 2, the second tank 3, and the third tank 4 are not limited to a cylindrical body, and may be formed by a triple tubular body having a rectangular end face. A tank structure may be used, and as shown in FIG. 5C, a tubular body having a rectangular end face may be eccentrically formed into a triple tank structure.
[0077]
FIG. 6 shows another embodiment of the water quality improvement system 1, in which the first tank 2 is provided with a vertically long inner cylinder so as to reach the oxygen-deficient water and the polluted water area. The closing plate 11 provided between the third tank 4 and the first tank 2 is provided so as to be entirely inclined, and the sediment naturally deposited on the closing plate 11 gathers in the collecting part 11a lower than other parts. As a result, the removal of the sediment by the suction pump 14 is facilitated.
[0078]
FIG. 7 is an explanatory diagram illustrating a schematic configuration of a water quality improvement system 1 according to another embodiment of the present invention. As shown in FIG. 7, the water quality improvement system 1 causes the water to be treated, which is pumped in the first tank 2 provided with the water pumping device 7 and the fine bubble generator 6 that generates fine bubbles from below, to overflow to the circulation tank 3a. Are distributed to the distribution tank 3a. Then, the water to be treated flows into the second tank 3 as a natural downward flow through the circulation tank 3a, and flows out of the third tank 4 connected to the second tank 3 as an upward flow into the closed water area.
[0079]
A reflux means 5 is provided between the first tank 2 and the second tank 3, and a floating material separation means 9 and a microorganism carrier 10 are provided in the second tank 3. In the third tank 4, sediments settled and separated from the water to be treated are deposited, and are deposited on the closing plate 11 and the closing plate 11 connected to the second tank 3 and having the lower accumulation part 11 a than other parts. In addition, a suction pump 14 for sucking and removing the sediment collected in the collecting section 11a is provided. The first tank 2, the second tank 3, and the third tank 4 are supported on the water surface by the float 12 and the gantry 13.
[0080]
As shown in FIG. 7, the water quality improvement system 1 does not have the first tank 2, the second tank 3, and the third tank 4 in a triple tank structure, but has a structure in which the first tank 2 to the third tank 4 are continuous. Alternatively, the system may be configured as a complete system in a tank.
[0081]
【The invention's effect】
The present invention has the above-described configuration, and has the following effects.
According to the first aspect of the present invention, anoxic water in a closed water area, and inorganic or organic fine particles originating in pollution and floating in a polluted water area are pumped in a first tank, and treated in a second tank. Microparticles of inorganic origin in water are floated, sedimented and separated and physically treated, and microorganisms supported on microbial carriers are used to biologically decompose particulate matter of organic origin in the water to be treated. Releases clear water into the closed water area. Since the water quality improvement system performs a complete treatment in the system, it releases clear water with an increased amount of dissolved oxygen while maintaining the water quality of the upper layer without disturbing the layer near the surface and the upper layer, and as a tap water source The water area of the upper water to be used can be expanded, and the water quality of a closed water area such as a dam lake or lake can be efficiently improved. Further, in a closed water area such as a relatively shallow lake which is not divided into an upper layer, a middle layer, and a lower layer, the water quality of the entire closed water area can be improved.
[0082]
In the invention according to claim 2, since the reflux means is provided between the first tank and the second tank to return to the first tank from below again, the residence time required for the treatment of the microorganisms carried on the microorganism carrier is provided. Can be adjusted.
[0083]
According to the third aspect of the invention, since the first tank, the second tank, and the third tank have a triple tank structure, a compact design that does not take up space as a complete water quality improvement system in the tank. It is possible to provide a water quality improvement system for closed water bodies, which realizes energy saving with a small operating power.
[0084]
According to the fourth aspect of the present invention, the sediment sedimentation means has a simple structure with a closing plate closing the space between the first tank and the third tank. It can be separated from the water to be treated without being mixed in the water.
[0085]
According to the fifth aspect of the present invention, since the closing plate serving as the sediment depositing means is inclined to provide an accumulation portion lower than other portions, the sediment deposited on the closing plate falls naturally. The sediment that has gathered at the accumulation part and has gathered can be easily removed.
[0086]
In the invention according to claim 6, since the second tank is a conical middle cylindrical body whose diameter is reduced downward, the surface area of the upper part of the second tank is enlarged, and the second tank flows into the second tank. In addition to reducing the flow rate of the water to be treated, promoting the flotation and separation of the fine particles attached to the microbubbles, reducing the surface area of the lower part of the second tank, increasing the surface area of the lower part of the third tank, By slowing the flow rate of the water to be treated flowing into the third tank from above, the sedimentation and separation of large particles that do not adhere to the fine bubbles can be promoted, and the physical treatment including flotation separation and sedimentation separation can be effectively performed.
[0087]
In the invention according to claim 7, the first tank, the second tank, and the third tank have a continuous structure, and the water to be treated pumped in the first tank is configured to flow by the head pressure. By using the natural flow of water, it is possible to provide a water quality improvement system that achieves low energy consumption and low operating costs.
[0088]
In the invention according to claim 8, since the float for floating the first tank, the second tank, and the third tank on the water surface is provided, the water quality improvement system can be moved to an arbitrary position in the closed water area, and the pollution degree can be reduced. Accordingly, it is possible to efficiently improve the water quality of anoxic water and polluted water in a wide range of closed water areas.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a water quality improvement system according to an embodiment of the present invention.
FIG. 2 is an explanatory view showing a state where FIG. 1 is installed in a closed water area.
FIG. 3 is a flowchart showing a purification method of the water quality improvement system.
FIG. 4 is a plan view showing a first tank, a second tank, a third tank, and a microorganism carrier of the water quality improvement system shown in FIG.
FIG. 5 is an explanatory view showing an embodiment of a first tank, a second tank, and a third tank of the water quality improvement system.
FIG. 6 is an explanatory diagram showing a schematic configuration of another embodiment of the water quality improvement system of the present invention.
FIG. 7 is an explanatory view showing a second embodiment of the present invention and showing a schematic configuration of a water quality improvement system.
[Explanation of symbols]
1; Water quality improvement system
2; First tank
3; second tank
3a; distribution tank
4; Third tank
5; reflux means
6; Microbubble generator
7; Pumping equipment
9; float removal means
10; Microbial carrier
11; closing plate
11a; accumulation unit
12; float
13;
14; suction pump

Claims

閉鎖水域の貧酸素水、汚濁水域の水質を改善する、閉鎖水域の水質改善システムであって、貧酸素水、汚濁水を上昇流として揚水する、揚水手段および下方から微細気泡を発生させる微細気泡発生手段を設けた第一槽と、該第一槽から流出した被処理水を、前記第一槽の上昇流の流速よりも遅い流速の下降流として流通して、被処理水中から浮上物及び沈降物を分離する機能を有し、浮上分離した浮上物除去手段および前記下降流の流通路に微生物担体を設けた第二槽と、該第二槽の下方から下降流として流出してきた被処理水を上昇流として閉鎖水域の上面に流出し、第二槽で沈降分離した沈降物を堆積しておく沈降物堆積手段および堆積した沈降物を除去する沈降物除去手段を設けた第三槽から成る閉鎖水域等の水質改善システム。A water quality improvement system for closed water areas that improves the quality of oxygen-poor water and polluted water in closed water areas. The first tank provided with the generating means, and the water to be treated flowing out of the first tank flows as a downward flow having a flow rate lower than the flow rate of the upward flow of the first tank, and a floating material and A second tank having a function of separating the sediment, and a floating object removing means having floated and separated, and a microbial carrier provided in a flow passage of the downflow; From the third tank provided with sediment sedimentation means and sediment removal means for removing the sediment sediment that flows out to the upper surface of the closed water area as water as an upflow and deposits sediment separated and settled in the second tank Water quality improvement system for closed water areas.

第一槽と第二槽に、第一槽から流出して第二槽に流入した被処理水の一部を再び下方から第一槽に還流する還流手段を設けた請求項１記載の閉鎖水域の水質改善システム。The closed water area according to claim 1, wherein the first tank and the second tank are provided with a reflux means for returning a part of the water to be treated flowing out of the first tank and flowing into the second tank to the first tank again from below. Water quality improvement system.

第一槽を、貧酸素水、汚濁水域まで到達する長さの内筒体とし、第二槽を、前記第一槽の外周に設け、該第一槽の壁部よりも水面上の高い位置となる壁部を備えた中筒体とし、第三槽を、前記第二槽の外周に設け、該第二槽の壁部よりも水面上で低い位置となる壁部を備えた外筒体とした請求項１または２記載の閉鎖水域の水質改善システム。The first tank is an anoxic water, an inner cylinder having a length reaching the polluted water area, the second tank is provided on the outer periphery of the first tank, a position higher on the water surface than the wall of the first tank. An outer cylindrical body having a wall portion that is provided on the outer periphery of the second tank and is located lower on the water surface than the wall portion of the second tank. The water quality improvement system for closed water bodies according to claim 1 or 2, wherein:

沈降物堆積手段を、第一槽の下部と第三槽の下部の間を閉塞する閉止板とした請求項３記載の閉鎖水域の水質改善システム。4. The system for improving water quality in a closed water area according to claim 3, wherein the sediment depositing means is a closing plate that closes a gap between a lower part of the first tank and a lower part of the third tank.

閉止板を傾斜し、他の部位よりも低い集積部を設けた請求項４記載の閉鎖水域の水質改善システム。The water quality improvement system for a closed water area according to claim 4, wherein the closing plate is inclined to provide an accumulation part lower than other parts.

第二槽を、下方に従って縮径する円錐状の中筒体とした請求項３、４または５記載の閉鎖水域の水質改善システム。The water quality improvement system for a closed water body according to claim 3, 4 or 5, wherein the second tank is a conical middle cylindrical body whose diameter decreases downward.

第二槽を、第一槽で揚水した被処理水が水頭圧により流通する第一槽から連続した槽とし、第三槽を、第二槽に連設した槽とした請求項１または２記載の閉鎖水域の水質改善システム。3. The second tank is a tank connected to the first tank through which water to be treated pumped in the first tank flows by the head pressure, and the third tank is a tank connected to the second tank. Water quality improvement system for closed water areas.

第一槽、第二槽および第三槽にフロートを設けた請求項１、２、３、４、５、６または７記載の閉鎖水域の水質改善システム。The water quality improvement system for a closed water area according to claim 1, wherein floats are provided in the first tank, the second tank, and the third tank.