JP3654991B2

JP3654991B2 - Water purification system

Info

Publication number: JP3654991B2
Application number: JP03578596A
Authority: JP
Inventors: 彰則南
Original assignee: Japan Vilene Co Ltd
Current assignee: Japan Vilene Co Ltd
Priority date: 1996-01-31
Filing date: 1996-01-31
Publication date: 2005-06-02
Anticipated expiration: 2016-01-31
Also published as: JPH09206773A

Description

【０００１】
【発明の属する技術分野】
この出願発明は、水浄化システムに関する。
【０００２】
【従来の技術】
従来の接触濾材は、礫、プラスチック板、波板、筒、網、ネット、織布等があるが、礫のように充填するタイプはＳＳ（ＳｕｓｐｅｄｅｄＳｏｌｉｄ：懸濁体固形分、懸濁液中の１μｍ以上の固形分）が目詰まりし易く、この傾向は原水のＢＯＤ，ＳＳが高いとより顕著になる。
一方、波板や、ネット、織り物を流速に対して平行に配置すると、目詰まりは生じにくいが、接触濾材の表面積が小さく、接触濾材の本来の使命であるＳＳ成分の濾過捕捉機能が十分でないという欠点がある。
この欠点を補うため、繊維径の太い塩化ビニリデン繊維を接触濾材として用いることが知られているが、繊維径の太い塩化ビニリデン繊維は、ＳＳ成分を非常に良く濾過捕捉する代わりに目詰まりし易く、目詰まりしたＳＳは、逆洗しても容易に元のポーラスな多孔質構造に戻らないという欠点があった。
ナイロン繊維からなる接触濾材も知られているが、親水性のため、逆洗しにくいという問題がある。
【０００３】
【発明が解決しようとする課題】
この出願発明者等は、これらの問題点について検討した結果、ポリオレフィン系繊維は、一般に繊維表面が疎水性であるためＳＳが付着しにくく、接触濾材としては最も不適と考えられていたが、ポリオレフィン系繊維の不織布からなる接触濾材の開孔径と厚みをコントロールすると、適度なＳＳが繊維表面に付着し、完全には繊維間を目詰まりさせないために、不織布内部を常に水が疎通し、実質的な生物膜の接触面積が増大し、非常に接触濾材として適していることを見いだした。
さらに、ポリオレフィン系接触濾材は、多量の生物膜やＳＳが付着し過ぎて元のポーラス構造に戻したい場合は、軽い振動や下からの曝気によって容易に生物膜や付着したＳＳが剥離し、元の構造に簡単に戻ることも見いだした。
この出願発明は、多量の生物膜やＳＳが付着し過ぎて元のポーラス構造に戻したい場合は、軽い振動や下からの曝気によって容易に生物膜や付着したＳＳが剥離し、元に戻る水浄化システムを提供することを目的とする。
また、少なくとも一つの槽にポリオレフィン系繊維の不織布からなる接触濾材を用いた好気槽−嫌気槽−好気槽からなる効率のよい水浄化システムを提供することも目的とする。
この出願発明により、様々な生活排水、都市河川、又は工場排水の生物学的な浄化処理法、とくに、ＢＯＤ、ＳＳが比較的高い原水の水浄化処理システムを提供することができる。
【０００４】
【課題を解決するための手段】
この出願発明は、前段の好気槽−嫌気槽−後段の好気槽からなり、且つ（前段の好気槽−嫌気槽）が２系統からなり、少なくとも１つの槽にポリオレフィン系繊維の不織布からなる接触濾材を用いる水浄化システムであって、
第１系統の（前段の好気槽−嫌気槽）と第２系統の（前段の好気槽−嫌気槽）と後段の好気槽とをこの順に直列に並べて連絡し、第１系統の（前段の好気槽−嫌気槽）の入口部に原水が流入するように流入路を配置し、後段の好気槽で処理された水を流入路に戻す循環路を設け、さらに流入路からの原水と循環路からの循環水とを直接第２系統の（前段の好気槽−嫌気槽）の入口部に送れるように流路の切り替えが可能なバイパスを設け、一方の系統の（前段の好気槽−嫌気槽）に原水及び循環水が流入している場合は、他の系統の（前段の好気槽−嫌気槽）は好気槽及び嫌気槽両方の曝気により汚泥を自己消化するようにして、原水及び循環水の流入と曝気による自己消化とが交互に行われるように配置した水浄化システムに関するものであり、また、前段の好気槽−嫌気槽−後段の好気槽からなり、且つ（前段の好気槽−嫌気槽）が２系統からなり、少なくとも１つの槽にポリオレフィン系繊維の不織布からなる接触濾材を用いる水浄化システムであって、
第１系統の（前段の好気槽−嫌気槽）と第２系統の（前段の好気槽−嫌気槽）とを並列に並べて配置し、各系統の（前段の好気槽−嫌気槽）に原水が流入するように流路切り替え手段を介して流入路を配置し、各系統の（前段の好気槽−嫌気槽）を後段の好気槽に連絡し、後段の好気槽で処理された水を流入路に戻す循環路を設け、一方の系統の（前段の好気増−嫌気槽）に原水及び循環水が流入している場合は、他の系統の（前段の好気槽−嫌気槽）は好気槽及び嫌気槽両方の曝気により汚泥を自己消化するようにして、原水及び循環水の流入と曝気による自己消化とが交互に行われるように配置したことを特徴とする水浄化システムに関する。
【０００５】
【発明の実施の形態】
この出願発明のポリオレフィンとしては、ポリエチレン、ポリプロピレン、ポリメチルペンテン等が使用される。
ポリオレフィン系繊維は、ポリオレフィン単独でもよいし、他の繊維の表面にポリオレフィンを被覆した複合構造の繊維でもよい。また、異種のポリオレフィンからなる複合繊維でもよい。
ポリオレフィンの組み合わせとしては、ポリエチレン、ポリプロピレン等が特に好ましい。
複数種の樹脂から構成される場合には、形状としては、いわゆる芯鞘型、偏芯型、サイドバイサイド型、海島型等の繊維等が好ましい。
【０００６】
不織布の開孔径としては、１〜２０ｍｍが好ましく、５〜１５ｍｍが更に好ましい。１ｍｍ以下では目詰まりし易いことがあり、逆洗しても再生しにくいことがある。また、２０ｍｍ以上では、接触濾材としての表面積が小さくなるため余り好ましくない。
【０００７】
濾材の厚みとしては、５〜１００ｍｍが好ましく、２０〜７５ｍｍが更に好ましい。５ｍｍ以下では保型性に欠けることがあり、枚数を多く必要とするため設置が面倒となる。また、１００ｍｍ以上では、厚過ぎて接触濾材内部まで水が浸透しにくくなる傾向が強い。
【０００８】
繊維径は５０〜１０００μｍが好ましく、１００〜５００μｍが更に好ましい。５０μｍ以下では剛性が低いことがあり、逆洗時に変形し易く取り扱いにくい。また、１０００μｍ以上では、太過ぎるため不織布の原料費が高くなり、生産性が低下し、高価となる。
【０００９】
不織布の配置は、例えば図１に示すように原則として流れに対して実質的に平行に配置することが好ましい。実質的に平行に配置することにより圧損を低くすることができる。強制的に水を送り込む場合などには、流れに対して３０度以内に傾けてもよい。
【００１０】
不織布と不織布との間の距離は、不織布の厚みによっても異なるが、不織布間の距離の総和が、不織布の厚みの総和の１０〜２００％となることが好ましい。１０％以下では不織布内部へのＳＳ付着が進行した場合の圧損が高くなることがある。また、２００％以上では、不織布間を流れる水が多過ぎ、接触濾材としての役割が小さくなることがある。
なお、原水のＢＯＤ、ＳＳが高い場合は、流入に近いところでは不織布間の距離の総和を、不織布の厚みの総和に対して２００％以上大きくし、徐々に１０％に近づけることにより、ＢＯＤの低減負荷を一定に保つようにしてもよい。
【００１１】
この出願発明では、好気槽−嫌気槽−好気槽からなる水浄化システムを用いることが好ましく、上記の各槽の少なくとも一つの槽に、ポリオレフィン系繊維の不織布からなる接触濾材を用いることが望ましい。とくに、嫌気槽には比較的密度の高い接触濾材が使用され、ＳＳの付着や生物膜の形成により、汚泥の付着量も多くなるので、これらの汚泥などに振動を与えたり、曝気することなどによって容易に剥離できるように、ポリオレフィン系繊維の不織布からなる接触濾材を用いるとよい。ＳＳの付着や生物膜の形成による汚泥の付着は、前段の好気槽と嫌気槽に集中するため、より好ましくは前段の好気槽と嫌気槽にポリオレフィン系繊維の不織布からなる接触濾材を用いることが望ましい。
【００１２】
なお、後段の好気槽にもポリオレフィン系繊維の不織布からなる接触濾材を用いてもよいが、後段の好気槽には、通常、ＳＳ濃度の低い水が通過するため、汚泥などの付着は前段の好気槽−嫌気槽ほどではなく、逆洗の要求もそれほど高くないので、他の繊維からなる不織布や、ネット、織物、組み紐などの他の素材からなる接触濾材を用いてもよい。ただし、処理すべき水のＳＳ濃度が高い場合などには、この後段の好気槽の接触濾材でもＳＳの付着が多くなって目詰りする可能性があるため、接触濾材の形状や配置はできるだけ目詰りの生じにくい構造であることが望ましく、例えば、図２に示すように、棒状又は紐状の接触濾材Ｃを、間隔を開けて、長手方向が鉛直方向となるように支持手段を用いて吊り下げるように配置することが望ましい。とくに、菊花状断面を有する棒状不織布接触材は、特開平６−２１２５４４号に記載されているように、表面積が大きいため、効率よく、多量にＳＳを付着させ、生物膜を保持することができるのでよい。
【００１３】
この出願発明では、浄化処理された水（流出水）を循環返送することが望ましい。例えば、上記の好気槽−嫌気槽−好気槽からなるシステムであれば、後段の好気槽から出た流出水を、前段の好気槽に循環路を通して返送することが望ましい。返送循環水の流量は、原水流入量の１０〜９００％が好ましく、２０〜４００％がより好ましい。
１０％以下の場合は、循環水量が少なすぎ、ＳＳ成分の凝集濾過効果が十分に得られないと共に、硝化の進んだ水の脱窒が行われにくい。また、９００％を越えると、嫌気槽と好気槽を通過する水の流量が原水流入量の１０倍を越えることになり、これに伴って速度も返送循環しない場合の１０倍以上となる。流速の設計値にもよるが、余りにも速い流速は、有用微生物の生育にとって好ましくなく、ＳＳ成分の接触濾材への付着も妨げられ、一旦付着した生物膜も剥がれやすくなることがある。
【００１４】
次に、ポリオレフィン系繊維の不織布からなる接触濾材を、好気槽−嫌気槽−好気槽からなるシステムの前段の好気槽と嫌気槽に使用し、かつ後段の好気槽から前段の好気槽へ浄化処理された水を返送循環する例を用いて、この出願発明の水浄化システムの作用について説明する。
【００１５】
上記の例では、ポリオレフィン系繊維の不織布からなる接触濾材の開孔径を大きくしてもＳＳ除去能に優れる。このため、前段の好気槽と嫌気槽で、ほとんどのＳＳ及び懸濁態ＢＯＤは付着除去され、後段の好気槽では、主として溶解性ＢＯＤの低減と溶解性アンモニア性窒素（ＮＨ₄−Ｎ）の硝酸系への硝化が促進される。
【００１６】
嫌気槽に開孔径の大きい接触濾材を用いた場合、本来であれば、ＳＳ成分の濾過効果はほとんど得られないが、前段の好気槽（好気性生物膜接触槽）を設けることにより、及び後段の好気槽（好気性生物膜接触槽）で処理された水を返送循環することにより、原水中のＳＳ成分の凝集性は著しく高まり、比較的開孔径の大きな接触濾材であっても容易に捕集、濾過され、水の透視度は著しく上り、ＳＳは著しく低下する。この理由は明らかではないが、好気性生物膜接触槽においてある種の粘着性物質をもった菌、もしくは菌の生成物が存在するか、ＳＳ成分と反応して凝集しやすい物質が返送循環水などの中に存在するためではないかと考えられる。
【００１７】
このＳＳ成分の粘着性や、接触濾材での捕集性は、前段の好気槽での曝気により促進され、より確実になる。この結果、ＳＳ成分は嫌気槽の接触濾材に集中して蓄積されるため、定期的な汚泥の除去が容易となる。なお、嫌気槽には、ポリオレフィン系繊維の不織布からなる接触濾材を用いているため、振動や強い曝気などの逆洗により、接触濾材に付着した汚泥を容易に除去できる。
【００１８】
前段の好気槽−嫌気槽で大部分のＳＳ及び懸濁態ＢＯＤは除去されるため、後段の好気槽（好気性生物膜接触槽）には、主として溶解性のＢＯＤやアンモニア性窒素（ＮＨ₄−Ｎ）が流入するので、後段の好気槽では効率的にＢＯＤの低減や硝化が行われる。なお、後段の好気槽には、ＳＳ及び懸濁態ＢＯＤがあまり流入しないので、接触濾材に付着した余分なＳＳなどを除去するための洗浄回数を大幅に減らすことができる。
【００１９】
後段の好気槽では、硝化菌（亜硝酸菌、硝酸菌）などによる硝化が行われて、ＮＨ₄はＮＯ₂やＮＯ₃に変換されるが、ＮＯ₃をＮ₂ガスにして水中から取り除くことによりＴ−Ｎ（トータル窒素量）を減らす、いわゆる脱窒は、高ＢＯＤと低ＤＯ（溶存酸素量）の環境が要求されるため、この系では進まない。しかし、この水浄化システムでは、後段の好気槽で処理された水を返送循環して、流入原水による高いＢＯＤとＳＳの付着した接触濾材内部の比較的低いＤＯの環境をもつ嫌気槽に戻しているため、脱窒も効率よく行われる。
【００２０】
さらに、１〜２０ｍｍの開孔径の大きい接触濾材を用いると、繊維表面に均一にＳＳのフロックが付着しやすく、しかも、繊維間は十分な空隙を有するため、流入原水及び返送循環水が接触濾材内部を均一にムラなく通過することができ、ＢＯＤの低減や脱窒を効率的に行うことができる。開孔径が１ｍｍより小さい接触濾材を用いると、ＳＳ成分が付着することにより目詰りし、場合によっては完全に閉塞されるおそれがある。このようになると、原水や循環水は実質的に接触濾材の外周部としか接触できなくなるため、微生物などによる効率的な有機物の低減や脱窒などが期待できなくなる。
【００２１】
なお、嫌気槽に接触濾材を使用しない場合には、ＳＳ成分は底に汚泥となって蓄積するだけであるので、完全嫌気となり、硫化水素ガスなどの腐敗臭が発生しやすくなる。また、この場合、返送循環水もＳＳとの接触機会が減るため効率的な脱窒は行われなくなる。
【００２２】
上記した水浄化システムでは、汚泥のほとんどは前段の好気槽−嫌気槽の接触濾材に捕集されるが、接触濾材にはポリオレフィン系繊維の不織布からなる接触濾材を使用しているため、振動を与えたり、強く曝気するといった逆洗を施すことにより、汚泥は接触濾材から脱離して槽の底部に堆積する。堆積した汚泥はバキュームなどにより除去すればよい。
【００２３】
なお、堆積した汚泥は自己消化させてもよく、この場合、前段の好気槽−嫌気槽を２系統設けて、一方の系統の汚泥を自己消化させている間、他方の系統に流入原水及び返送循環水を流すようにすれば、水の浄化を中断することなく、汚泥を減らすことができ、大幅にメンテナンスコストを削減することができる。２系統の好気槽−嫌気槽には、同じ能力のものを使用してもよく、また異なる能力のものを使用してもよいが、いずれにも接触濾材としてポリオレフィン系繊維の不織布を使用することが望ましい。
【００２４】
このような水浄化システム１としては、例えば、図３に示すように、第１系統の前段４ａの好気槽２−嫌気槽３と第２系統の前段４ｂの好気槽２−嫌気槽３と後段５の好気槽２とを順に縦に並べて連絡し、流入路６からの原水７と循環路８からの循環水とを直接第２系統の前段４ｂの好気槽２−嫌気槽３に送れるようにバイパスを設けると共に、後段５の好気槽２から第１系統の前段４ａの好気槽２に浄化処理水を返送循環できるように循環路８を設けたものである。
【００２５】
この水浄化システム１では、図４（ａ）に示すように、第１系統の前段４ａの好気槽２−嫌気槽３、第２系統の前段４ｂの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この際、好気槽２に該当する図の斜線で示した部分では散気管などで曝気して好気状態を保つ。一定期間稼働すると、ＳＳの付着や生物膜の成長により、多量の汚泥が主として第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着する。
【００２６】
このようにして多量の汚泥が第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着した後、図４（ｂ）に示すように、バイパスを用いて原水７及び循環路８からの循環水を第２系統の前段４ｂの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この間、第１系統の前段４ａの好気槽２−嫌気槽３には通水せず、全面曝気することにより、接触濾材から汚泥を除去すると共に、自己消化させる。
【００２７】
接触濾材から汚泥を除去すると共に、自己消化させた後、図４（ｃ）に示すように、流路を元に戻し、第２系統の前段４ｂの好気槽２−嫌気槽３を全面曝気して、接触濾材から汚泥を除去すると共に、自己消化させる。この状態では、汚泥はほとんど第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着するため、通水状態にしていても、全面曝気することにより、第２系統の前段４ｂの好気槽２−嫌気槽３の汚泥を自己消化させることができる。
【００２８】
以上のような処理により原水を浄化した後は、図４（ｂ）と図４（ｃ）の処理を繰り返すことによって、水の浄化を連続的に行いながら、汚泥を減らすことができる。
【００２９】
図５は２系統の前段４の好気槽２−嫌気槽３を用いた別の例を示すものであって、第１系統の前段４ａの好気槽２−嫌気槽３と第２系統の前段４ｂの好気槽２−嫌気槽３とを横に並べ、流入路６から各々に流路切り換え１０を介して配管すると共に、各々を後段５の好気槽２に連絡したものであり、しかも、後段５の好気槽２から流入路６に処理水９を返送循環できるように循環路８を設けたものである。
【００３０】
この水浄化システム１では、図６（ｄ）に示すように、まず第１系統の前段４ａの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この際、好気槽２に該当する図の斜線で示した部分では、散気管などで曝気して好気状態を保つ。一定期間稼働すると、ＳＳの付着や生物膜の成長により、多量の汚泥が第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着する。
【００３１】
多量の汚泥が第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着した後、図６（ｅ）に示すように、流路を切り換えて原水７及び循環路８からの循環水を第２系統の前段４ｂの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この間、第１系統の前段４ａの好気槽２−嫌気槽３には通水せず、全面曝気することにより、接触濾材から汚泥を除去すると共に、自己消化させる。
【００３２】
自己消化させた後、図６（ｆ）に示すように、流路を元に戻し、第１系統の前段４ａの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この間、第２系統の前段４ｂの好気槽２−嫌気槽３には通水せず、全面曝気して、接触濾材から汚泥を除去すると共に自己消化させる。
【００３３】
このようにして原水を処理した後は、図６（ｅ）と図６（ｆ）の処理を交互に繰り返すことによって、第１系統の前段４ａの好気槽２−嫌気槽３と第２系統の前段４ｂの好気槽２−嫌気槽３で各々交互に水の浄化と自己消化を行うことによって、水の浄化を連続的に行いながら、汚泥を減らすことができる。
【００３４】
図７は２系統の前段４の好気槽２−嫌気槽３を用いた別の例を示すものであって、図３で示した水浄化システムの第１系統の前段４ａの好気槽２−嫌気槽３の出口部から後段５の好気槽２に至るバイパスを設けた構造となっている。
この例では、各バイパスの流路を切り換えることによって、水の流れを第１系統の前段４ａの好気槽２−嫌気槽３と後段５の好気槽２、及び第２系統の前段４ｂの好気槽２−嫌気槽３と後段５の好気槽２とに切り換えることができるようになっており、第１系統と第２系統の前段４の好気槽２−嫌気槽３は縦に並んでいるが、各槽の水の移動の仕方は、実質的に図５の第１系統と第２系統の前段４の好気槽２−嫌気槽３を横に並べた場合と同じである。
【００３５】
この水浄化システム１では、図８（ｇ）に示すように、まず第１系統の前段４ａの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて浄化水を循環することによって水を浄化する。この際、好気槽２に該当する図の斜線で示した部分では散気管などで曝気して好気状態を保つ。一定期間稼働すると、ＳＳの付着や生物膜の成長により、多量の汚泥が第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着する。
【００３６】
多量の汚泥が第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材に付着した後、図８（ｈ）に示すように、流路切り替え１０により流路を切り換えて原水７及び循環路８からの循環水を第２系統の前段４ｂの好気槽２−嫌気槽３、後段５の好気槽２の順に通水すると共に、循環路８を用いて処理水を循環することによって水を浄化する。この間、第１系統の前段４ａの好気槽２−嫌気槽３には通水せず、全面曝気することにより、接触濾材から汚泥を除去すると共に、自己消化させる。
【００３７】
接触濾材から汚泥を除去すると共に、自己消化させた後、図８（ｉ）に示すように、流路を元に戻し、第１系統の前段４ａの好気槽２−嫌気槽３、後段５の好気槽２に順に通水すると共に、循環路を用いて処理水を循環することによって水を浄化する。この間、第２系統の前段４ｂの好気槽２−嫌気槽３には通水せず、全面曝気して、接触濾材から汚泥を除去すると共に自己消化させる。
【００３８】
このようにして原水を処理した後、図８（ｈ）と図８（ｉ）の処理を交互に繰り返すことによって、第１系統の前段４ａの好気槽２−嫌気槽３と第２系統の前段４ｂの好気槽２−嫌気槽３で各々交互に水の浄化と自己消化を行うことによって、水の浄化を連続的に行いながら、汚泥を減らすことができる。
【００３９】
以下、具体的に実施例によりこの出願発明を説明する。
【実施例】
実施例１
平均繊維径６００μｍ、芯成分がポリプロピレンで鞘成分がポリエチレンの芯鞘型複合繊維を繊維接着して、厚み５０ｍｍ、見掛け密度０．０４ｇ／ｃｍ³の不織布を作製した。なお、不織布の表面を投影コピーして求めた平均開孔経は約６ｍｍであった。この不織布を幅３０ｃｍ、長さ１００ｃｍに裁断して接触濾材Ａとした。
平均繊維径３００μｍ、芯成分がポリプロピレンで鞘成分がポリエチレンの芯鞘型複合繊維を繊維接着して、厚み５０ｍｍ、見掛け密度０．０５ｇ／ｃｍ³の不織布を作製した。なお、不織布の表面を投影コピーして求めた平均開孔経は約１．５ｍｍであった。この不織布を幅３０ｃｍ、長さ１００ｃｍに裁断して接触濾材Ｂとした。
ポリエステル系繊維からなる目付２５０ｇ／ｍ²、厚み７ｍｍの繊維接着不織布を幅８ｃｍに裁断したものを４枚重ね、幅方向の中央部分を圧縮しながら長手方向に連続的に超音波シールして、シール部を中心に８枚の不織布片が放射状に延びる菊花状断面を有する直径約８ｃｍの棒状不織布を得た。この棒状不織布を長さ３０ｃｍに裁断して接触濾材Ｃとした。
生活排水路の横に、幅３０ｃｍ、深さ３０ｃｍ、長さ５０ｍの浄化用水路を作製した。この浄化用水路の各好気槽及び嫌気槽に該当する領域の底部に曝気用の散気管を全面に設けると共に、上記の接触濾材Ａ、Ｂ、Ｃを下記に述べるように配置して、図９に示すような、流れ方向に縦に２系統の前段の好気槽−嫌気槽と後段の好気槽とを並べて配置した水浄化システムを得た。なお、２系統の前段の好気槽−嫌気槽の下にある散気管は５ｍごとに独立してＯＮ、ＯＦＦが可能なようにセットした。
前段の好気槽−嫌気槽には、図１に示すように、接触濾材Ａ１１、接触濾材Ｂ１２を配置した領域を用いた。まず、前段の好気槽には、３枚の接触濾材Ａ１１を、表面が互いに平行で、かつ流れに平行となるように幅方向に等間隔に配置した領域を流れ方向に５ｍ（接触濾材Ａ１１は流れ方向に５枚ずつ配置される）設けて用いる。次に、嫌気槽には、４枚の接触濾材Ａ１１を表面が互いに平行で、かつ流れに平行となるように幅方向に等間隔に配置した領域を、流れ方向に４ｍ、４枚の接触濾材Ｂを、表面が互いに平行で、かつ流れに平行となるように幅方向に等間隔に配置した領域を流れ方向に１ｍ、５枚の接触濾材Ｂ１２を表面が互いに平行で、かつ流れに平行となるように幅方向に等間隔に配置した領域を流れ方向に５ｍとなるように順次設けて用いる。なお、ここで幅方向の不織布間距離の総和／不織布厚みの総和は、３枚、４枚、５枚の場合、各々１５／１５×１００＝１００％、１０／２０×１００＝５０％、５／２５×１００＝２０％となる。
また、後段の好気槽には、図２に示すように、接触濾材Ｃ１３の棒状不織布の長手方向が鉛直方向となり、かつ接触濾材Ｃ１３の中心と接触濾材Ｃ１３の中心とが、互いに幅方向に１０ｃｍ間隔で一列に並び、各列が流れ方向に１０ｃｍ間隔となるように、支持用のバーから吊り下げて千鳥状に配置した領域を、流れ方向に２０ｍ設けて用いる。
以下に上記の水浄化システムを使用して、生活排水の水浄化を行う方法を示す。なお、この水浄化システムの各槽の配置や流路は、図３、図４で説明した水浄化システムと実質的に同じである。
まず、生活排水を１０リットル／分の流量でポンプアップして、浄化用水路に流入させる。流入水は、図４（ａ）に示すように、第１系統の前段４ａの好気槽２−嫌気槽３、第２系統の前段４ｂの好気槽２−嫌気槽３、後段５の好気槽２の順に通水して浄化され、流出される。処理水の一部は循環路８を通して流入口に流量１０リットル／分で循環する。すなわち、流入、流出水量は１０リットル／分、水浄化システム１の各槽での流量は２０リットル／分となる。なお、前段４の第１系統及び第２系統の流入口から５ｍの領域は、各々曝気して好気状態にして好気槽２とし、残りの１０ｍの領域は各々曝気せずに嫌気状態にして嫌気槽２として使用し、後段５の好気槽２は全体を曝気して好気状態にして使用する。
水浄化システムの稼働約１カ月後の流入原水と第２系統の前段４ｂの好気槽２−嫌気槽３の出口、処理水の水質データを調べ、表１に示す。表１から明らかなように、第２系統の前段４ｂの好気槽２−嫌気槽３の出口におけるＳＳ値は非常に低く、前段の好気槽２−嫌気槽３の接触濾材Ａ１１、接触濾材Ｂ１２によって大部分のＳＳ及び懸濁体ＢＯＤ成分が補足されていることが分る。
また、窒素成分は、ＮＨ₄−Ｎ（アンモニア性窒素）は後段の好気槽内で消化菌によって無毒のＮＯ₃−Ｎ（硝酸態窒素）に変換され、ＮＯ₃−Ｎは循環返送により前段の嫌気槽内で脱窒されてＴ−Ｎ（トータル窒素：総窒素量）が約半分まで低減される。
稼働約１カ月後、第１系統の前段４ａの好気槽２−嫌気槽３の接触濾材Ａ１１、接触濾材Ｂ１２には、ＳＳの付着や生物膜などによる多量の汚泥が付着しており、これを除去するために、図４（ｂ）に示すように、流入水及び循環水を第１系統の前段４ａの好気槽２−嫌気槽３に流入しないように流路を遮断すると共に、バイパスを使って直接第２系統の前段４ｂの好気槽２−嫌気槽３に流入させる。このように、第１系統の前段４ａの好気槽２−嫌気槽３に水が流入しない状態で、好気槽２と嫌気槽３の両方を曝気（全曝気）するように切り換えて３週間運転した結果、第１系統の前段４ａの好気槽２−嫌気槽３の汚泥は自己消化のため大幅に減少した。
なお、この間の流入水（生活排水）の浄化は、図４（ｂ）に示すように、第２系統の前段４ｂの好気槽２−嫌気槽３と後段５の好気槽２とに通水し、かつ流出水の一部を循環返送することにより行われ、図４（ａ）の場合と同様の水質浄化効果が得られた。
次いで、図４（ｃ）に示すように、水の流路を元に戻し、第１系統の前段４ａの好気槽２−嫌気槽３の嫌気槽での曝気を止め、第２系統の前段４ｂの好気槽２−嫌気槽３の好気槽２と嫌気槽２の両方を曝気（全曝気）するように切り換えて３週間運転した結果、第２系統の前段４ｂの好気槽２−嫌気槽３の汚泥も減少した。
この後、図４（ｂ）と図４（ｃ）の処理を交互に繰り返すことで、第１系統及び第２系統のいずれの前段４の好気槽２−嫌気槽３にも汚泥による詰まりを生じることなく、水の浄化処理を効率よく行うことができた。
【００４０】
【表１】

【００４１】
実施例２
図５に示すように、第１系統の前段４ａの好気槽２−嫌気槽３と第２系統の前段４ｂの好気槽２−嫌気槽３とを横並びに配置し、流入原水（生活排水）及び循環水が各々に直接流入するように配管すると共に、いずれか一方のみに流入するように流路切り換えを設けた。また、各系統の前段４の好気槽２−嫌気槽３は、各々後段５の好気槽２に送水できるように配管した。さらに、後段５の好気槽２から出た処理水の一部を流入口に循環できるように循環路を形成して、水浄化システムを形成した。
なお、前段４の好気槽２−嫌気槽３は、実施例１の浄化用水路の代りに幅３０ｃｍ、深さ３０ｃｍ、長さ１５ｍの浄化用水路を用いたこと以外は、実施例１と同様にして、接触濾材Ａ１１、接触濾材Ｂ１２を配管し、かつ底部に散気管を設けて形成した。また、後段５の好気槽２も、実施例１の浄化用水路の代りに幅３０ｃｍ、深さ３０ｃｍ、長さ２０ｍの浄化用水路を用いたこと以外は、実施例１と同様にして、接触濾材Ｃ１３を配管し、かつ底部に散気管を設けて形成した。以下にこの水浄化システムを使用して、生活排水の水浄化を行う方法を示す。まず、生活排水を１０リットル／分の流量でポンプアップして、浄化用水路に流入する。流入水は、図６（ｄ）に示すように、第１系統の前段４ａの好気槽２−嫌気槽３のみに流入され、後段５の好気槽２を通って浄化され、流出される。浄化水の一部は循環路を通して流入口に流量１０リットル／分で返送循環する。すなわち、流入、流出水量は１０リットル／分、水浄化システムの各槽での流量は２０リットル／分となる。なお、前段の第１系統の流入口から５ｍの領域は曝気して好気状態にして好気槽２とし、残りの１０ｍの領域は各々曝気せずに嫌気状態にして嫌気槽３として使用し、後段５の好気槽２は全体を曝気して好気状態にして使用する。
水浄化システムの稼働約１カ月後の流入原水と第１系統の前段４ａの好気槽２−嫌気槽３の出口、処理水の水質データを調べ、表２に示す。表２から明らかなように、第１系統の前段４ａの好気槽２−嫌気槽３の出口におけるＳＳ値は非常に低く、前段４の好気槽２−嫌気槽３の接触濾材Ａ１１、接触濾材Ｂ１２によって大部分のＳＳ及び懸濁体ＢＯＤ成分が補足されていることが分かる。また、窒素成分は、ＮＨ₄−Ｎ（アンモニア性窒素）は後段の好気槽内で消化菌によって無毒のＮＯ₃−Ｎ（硝酸態窒素）に変換され、ＮＯ₃−Ｎは循環返送により前段の嫌気槽内で脱窒されてＴ−Ｎ（トータル窒素：総窒素量）が約半分まで低減される。
稼働約１カ月後、第１系統の前段の好気槽−嫌気槽の接触濾材Ａ１１、接触濾材Ｂ１２には、ＳＳの付着や生物膜などによる多量の汚泥が付着しており、これを除去するために、図６（ｅ）に示すように、流入原水及び循環水を第１系統の前段４ａの好気槽−嫌気槽に流入しないように流路切り換えによって流路を切り換えて、直接第２系統の前段４ｂの好気槽２−嫌気槽３に流入させる。このように、第１系統の前段４ａの好気槽２−嫌気槽３に水が流入しない状態で、好気槽２と嫌気槽３の両方を曝気（全曝気）するように切り換えて３週間運転した結果、第１系統の前段４ａの好気槽２−嫌気槽３の汚泥は自己消化のため大幅に減少した。
なお、この間の流入水（生活排水）の浄化は、図６（ｅ）に示すように、第２系統の前段４ｂの好気槽２−嫌気槽３と後段５の好気槽２とに通水し、かつ流出水の一部を循環返送することにより行われる。ここで第２系統の流入口から５ｍの領域は曝気して好気状態にして好気槽とし、残りの１０ｍの領域は各々曝気せずに嫌気状態にして嫌気槽として使用し、後段５の好気槽２は全体を曝気して好気状態にして使用する。第２系統の前段４ｂの好気槽２−嫌気槽３の出口部での水質を調べたところ、図６（ｄ）の場合の第１系統の前段４ａの好気槽２−嫌気槽３の出口部での水質と全く同様であり、水質浄化の効果も同様であった。
次いで、図６（ｆ）に示すように、流入原水と循環水とを第２系統の前段４ｂの好気槽２−嫌気槽３に流入しないように流路切り換え１０によって流路を切り換えて、直接第１系統の前段４ａの好気槽２−嫌気槽３に流入させ、水の流路を元に戻す。第１系統の前段４ａの好気槽２−嫌気槽３の嫌気槽での曝気を止め、第２系統の前段４ｂの好気槽２−嫌気槽３の好気槽２と嫌気槽３の両方を曝気（全曝気）するように切り換えて３週間運転した結果、第２系統の前段４ｂの好気槽２−嫌気槽３の汚泥も自己消化のため大幅に減少した。
この後、図６（ｅ）と図６（ｆ）の処理を交互に繰り返すことで、第１系統及び第２系統のいずれの前段４の好気槽２−嫌気槽３にも汚泥による詰まりを生じることなく、水の浄化処理を効率よく行うことができた。なお、この実施例の水浄化システムでは、汚泥の自己消化を行うために流路を変えても、常にほぼ均一な水の浄化効果が得られた。
【００４２】
【表２】

【００４３】
【発明の効果】
この出願発明の水浄化システムに使用する接触濾材は、ポリオレフィン系繊維からなる不織布、特に、ポリオレフィン系不織布の開孔径と厚みをコントロールすることにより、適度なＳＳが繊維表面に付着し、完全には繊維間を目詰まりさせないために、不織布内部を常に水が流通し、実質的な生物膜の接触面積が増大し、接触濾材、特に、多量のＳＳ、ＢＯＤを有する排水等を処理する接触濾材として適している。
また、多量のＳＳや生物膜が付着し過ぎたため付着したＳＳや生物膜を除去して元のポーラス構造に戻したい場合は、軽い振動や下からの曝気によって容易にＳＳや生物膜が剥離するので、簡単に元に戻すことができる。
したがって、この出願発明の水浄化システムは、多量の生物が付着し過ぎて元のポーラス構造に戻したい場合は、軽い振動や下からの曝気によって容易にＳＳや生物膜などが剥離し、元に戻すことができるので、除去すべきＳＳ、ＢＯＤが多量に含まれている水の浄化にとくに適している。
この出願発明の水浄化システムは、生活雑排水、農村集落雑排水、コミュニティー生活排水、都市河川、キャンプ場の生活雑排水、食品工場の排水の浄化、池、ダムの浄化に適している。
【図面の簡単な説明】
【図１】この出願発明の前段の好気槽と嫌気槽の１系統を上から見た模式図
【図２】この出願発明の後段の好気槽を上から見た模式図
【図３】この出願発明の好気槽−嫌気槽−好気槽の水槽の水浄化システムの一例
【図４】水浄化システムの一例の水の流れを説明する図
【図５】この出願発明の好気槽−嫌気槽−好気槽の水槽の水浄化システムの他の例
【図６】水浄化システムの他の例の水の流れを説明する図
【図７】この出願発明の好気槽−嫌気槽−好気槽の水槽の水浄化システムの他の例
【図８】水浄化システムの他の例の水の流れを説明する図
【図９】この出願発明の好気槽−嫌気槽−好気槽の水槽の水浄化システムの他の例
【符号の説明】
１水浄化システム
２好気槽
３嫌気槽
４前段
４ａ第１系統の前段
４ｂ第２系統の前段
５後段
６流入路
７原水
８循環路
９処理水
１０流路切り替え
１１接触濾材Ａ
１２接触濾材Ｂ
１３接触濾材Ｃ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water purification system.
[0002]
[Prior art]
Conventional contact filter media include gravel, plastic plate, corrugated plate, tube, net, net, woven fabric, etc., but the type that fills like gravel is SS (Suspended Solid: suspension solid content, in suspension) The solid content of 1 μm or more is easily clogged, and this tendency becomes more remarkable when the BOD and SS of the raw water are high.
On the other hand, when corrugated plates, nets, and weaves are arranged in parallel to the flow velocity, clogging is unlikely to occur, but the surface area of the contact filter medium is small, and the SS component filtration trapping function, which is the original mission of the contact filter medium, is not sufficient. There is a drawback.
In order to compensate for this drawback, it is known to use a vinylidene chloride fiber having a large fiber diameter as a contact filter medium. However, a vinylidene chloride fiber having a large fiber diameter is prone to clogging instead of being very well filtered and trapped. The clogged SS has a drawback that it does not easily return to the original porous structure even when backwashed.
A contact filter medium made of nylon fiber is also known, but has a problem that it is difficult to backwash due to its hydrophilic property.
[0003]
[Problems to be solved by the invention]
As a result of studying these problems, the inventors of the present application have found that polyolefin fibers are generally the most unsuitable as a contact filter medium because the fiber surface is generally hydrophobic and SS hardly adheres. By controlling the pore size and thickness of the contact filter medium made of a nonwoven fabric made of fiber, moderate SS adheres to the fiber surface and does not completely clog the fibers. It has been found that the contact area of various biofilms is increased and it is very suitable as a contact filter medium.
Furthermore, when a large amount of biofilm or SS is too adhered to the polyolefin-based contact filter medium and it is desired to return to the original porous structure, the biofilm or attached SS easily peels off by light vibration or aeration from below, I also found it easy to go back to the structure.
In the invention of this application, when a large amount of biofilm or SS adheres too much and it is desired to return to the original porous structure, the biofilm or SS attached easily peels off due to light vibration or aeration from below, and returns to the original water structure. It aims to provide a purification system.
It is another object of the present invention to provide an efficient water purification system comprising an aerobic tank, an anaerobic tank, and an aerobic tank using a contact filter medium made of a polyolefin-based nonwoven fabric in at least one tank.
By this invention, it is possible to provide a biological purification treatment method for various domestic wastewater, urban rivers, or factory wastewater, in particular, a water purification treatment system for raw water having relatively high BOD and SS.
[0004]
[Means for Solving the Problems]
The invention of this application isThe front aerobic tank-anaerobic tank-the latter aerobic tank, and (the front aerobic tank-anaerobic tank) are composed of two systems, and at least one tank uses a contact filter medium made of a nonwoven fabric of polyolefin fibers. A water purification system,
The first system (front aerobic tank-anaerobic tank), the second system (front aerobic tank-anaerobic tank) and the rear aerobic tank are arranged in series in this order, and the first system ( An inflow path is arranged so that raw water flows into the inlet of the previous aerobic tank-anaerobic tank), a circulation path is provided to return the water treated in the subsequent aerobic tank to the inflow path, and from the inflow path A bypass capable of switching the flow path is provided so that the raw water and the circulating water from the circulation path can be sent directly to the inlet of the second system (previous aerobic tank-anaerobic tank). When raw water and circulating water flow into the (aerobic tank-anaerobic tank), other systems (previous aerobic tank-anaerobic tank) self-digest sludge by aeration in both the aerobic tank and the anaerobic tank In this way, the water purification system is arranged so that inflow of raw water and circulating water and self-digestion by aeration are performed alternatelyAnd alsoThe front aerobic tank-anaerobic tank-the latter aerobic tank, and (the front aerobic tank-anaerobic tank) are composed of two systems, and at least one tank uses a contact filter medium made of a nonwoven fabric of polyolefin fibers. A water purification system,
The first system (previous aerobic tank-anaerobic tank) and the second system (previous aerobic tank-anaerobic tank) are arranged in parallel, and each system (previous aerobic tank-anaerobic tank). An inflow path is arranged through the channel switching means so that raw water flows into the system, and each system's (previous aerobic tank-anaerobic tank) is connected to the subsequent aerobic tank and processed in the subsequent aerobic tank If a circulation path is provided to return the discharged water to the inflow path, and raw water and circulating water are flowing into (anterior aerobic increase-anaerobic tank) of one system, the other system (anterior aerobic tank) -Anaerobic tank) is characterized in that sludge is self-digested by aeration in both aerobic tank and anaerobic tank, and the inflow of raw water and circulating water and self-digestion by aeration are performed alternately. Water purification systemAbout.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
As the polyolefin of the present invention, polyethylene, polypropylene, polymethylpentene and the like are used.
The polyolefin-based fiber may be a single polyolefin or a fiber having a composite structure in which the surface of another fiber is coated with polyolefin. Moreover, the composite fiber which consists of a different kind of polyolefin may be sufficient.
As the combination of polyolefins, polyethylene, polypropylene and the like are particularly preferable.
When composed of a plurality of types of resins, the shape is preferably a so-called core-sheath type, eccentric type, side-by-side type, sea-island type, or the like.
[0006]
As a hole diameter of a nonwoven fabric, 1-20 mm is preferable and 5-15 mm is still more preferable. If it is 1 mm or less, clogging may occur easily, and it may be difficult to regenerate even after backwashing. On the other hand, if it is 20 mm or more, the surface area as the contact filter medium becomes small, which is not preferable.
[0007]
The thickness of the filter medium is preferably 5 to 100 mm, and more preferably 20 to 75 mm. If it is 5 mm or less, the shape-retaining property may be lacking, and the installation becomes troublesome because a large number of sheets are required. Moreover, if it is 100 mm or more, there is a strong tendency that water is too thick to penetrate into the contact filter medium.
[0008]
The fiber diameter is preferably 50 to 1000 μm, and more preferably 100 to 500 μm. If it is 50 μm or less, the rigidity may be low, and it is easily deformed and difficult to handle during backwashing. On the other hand, when the thickness is 1000 μm or more, the raw material cost of the nonwoven fabric increases because it is too thick, and the productivity is lowered and the cost is increased.
[0009]
For example, as shown in FIG. 1, the nonwoven fabric is preferably arranged substantially in parallel to the flow in principle. By arranging them substantially in parallel, the pressure loss can be reduced. For example, when water is forcibly fed, it may be tilted within 30 degrees with respect to the flow.
[0010]
Although the distance between a nonwoven fabric and a nonwoven fabric also changes with thickness of a nonwoven fabric, it is preferable that the sum total of the distance between nonwoven fabrics will be 10-200% of the sum total of the thickness of a nonwoven fabric. If it is 10% or less, the pressure loss may increase when SS adheres to the inside of the nonwoven fabric. Moreover, if it is 200% or more, there will be too much water flowing between nonwoven fabrics, and the role as a contact filter medium may become small.
In addition, when the BOD and SS of raw water are high, the sum of the distances between the nonwoven fabrics near the inflow is increased by 200% or more with respect to the total thickness of the nonwoven fabrics, and gradually approaches 10%. The reduced load may be kept constant.
[0011]
In this application invention, it is preferable to use a water purification system comprising an aerobic tank, an anaerobic tank, and an aerobic tank, and a contact filter medium made of a nonwoven fabric of polyolefin fibers is used in at least one of the above tanks. desirable. In particular, contact filter media with relatively high density is used in anaerobic tanks, and the amount of sludge attached increases due to the adhesion of SS and the formation of biofilms, so these sludges are vibrated or aerated. It is preferable to use a contact filter medium made of a nonwoven fabric of polyolefin fibers so that it can be easily peeled off. Since SS adhesion and sludge adhesion due to biofilm formation concentrate in the previous aerobic tank and anaerobic tank, more preferably, a contact filter medium made of polyolefin fiber nonwoven fabric is used in the previous aerobic tank and anaerobic tank. It is desirable.
[0012]
In addition, although a contact filter medium made of a polyolefin fiber nonwoven fabric may be used in the latter-stage aerobic tank, since water having a low SS concentration usually passes through the latter-stage aerobic tank, adhesion of sludge etc. Since the requirement for backwashing is not so high as the previous aerobic tank-anaerobic tank, a contact filter medium made of other materials such as non-woven fabrics, nets, woven fabrics and braids may be used. However, when the SS concentration of water to be treated is high, the contact filter medium in the subsequent aerobic tank may clog due to increased SS adhesion, so the shape and arrangement of the contact filter medium can be as much as possible. For example, as shown in FIG. 2, the contact filter medium C in the form of a bar or string is spaced apart from each other by using a supporting means so that the longitudinal direction is the vertical direction. It is desirable to arrange it so that it hangs. In particular, a rod-shaped nonwoven fabric contact material having a chrysanthemum-like cross section has a large surface area as described in JP-A-6-212544, and therefore can efficiently attach a large amount of SS and hold a biofilm. So good.
[0013]
In this invention, it is desirable to circulate and return the purified water (outflow water). For example, in the case of a system composed of the above aerobic tank-anaerobic tank-aerobic tank, it is desirable to return the effluent water from the subsequent aerobic tank to the preceding aerobic tank through the circulation path. The flow rate of the return circulating water is preferably 10 to 900% of the inflow amount of raw water, and more preferably 20 to 400%.
In the case of 10% or less, the amount of circulating water is too small, and the aggregation filtration effect of the SS component cannot be obtained sufficiently, and denitrification of water that has advanced nitrification is difficult to be performed. On the other hand, if it exceeds 900%, the flow rate of water passing through the anaerobic tank and the aerobic tank will exceed 10 times the amount of raw water inflow, and accordingly the speed will be 10 times or more of the case where the return circulation is not performed. Although depending on the design value of the flow rate, a too high flow rate is not preferable for the growth of useful microorganisms, the adhesion of the SS component to the contact filter medium is also hindered, and the biofilm once attached may be easily peeled off.
[0014]
Next, the contact filter medium made of polyolefin fiber non-woven fabric is used in the aerobic tank and the anaerobic tank in the front stage of the system consisting of the aerobic tank, the anaerobic tank, and the aerobic tank, and from the subsequent aerobic tank to the front stage. The operation of the water purification system of the present invention will be described using an example of returning and circulating the purified water to the air tank.
[0015]
In the above example, the SS removal ability is excellent even when the pore diameter of the contact filter medium made of a polyolefin-based nonwoven fabric is increased. For this reason, most of the SS and suspended BOD are adhered and removed in the former aerobic tank and the anaerobic tank, and in the latter aerobic tank, mainly the reduction of the soluble BOD and the soluble ammonia nitrogen (NH_Four-N) nitrification to nitric acid is promoted.
[0016]
When a contact filter medium with a large pore diameter is used in an anaerobic tank, originally, the SS component can hardly be filtered, but by providing a previous aerobic tank (aerobic biofilm contact tank), and By returning and circulating the water treated in the aerobic tank (aerobic biofilm contact tank) in the latter stage, the cohesiveness of the SS component in the raw water is remarkably increased, and even a contact filter medium having a relatively large pore diameter can be easily obtained. Collected and filtered, the water transparency increases remarkably and SS decreases remarkably. The reason for this is not clear, but in the aerobic biofilm contact tank, there are bacteria with a certain sticky substance, or a product of the fungus, or a substance that easily aggregates by reacting with the SS component is returned to the circulating water. It may be because it exists in
[0017]
The adhesiveness of the SS component and the trapping property with the contact filter medium are promoted by aeration in the preceding aerobic tank and become more reliable. As a result, since the SS component is concentrated and accumulated in the contact filter medium of the anaerobic tank, periodic sludge removal is facilitated. In addition, since the anaerobic tank uses a contact filter medium made of a polyolefin-based nonwoven fabric, sludge adhering to the contact filter medium can be easily removed by backwashing such as vibration or strong aeration.
[0018]
Since most of SS and suspended BOD are removed in the aerobic tank-anaerobic tank in the former stage, the aerobic tank (aerobic biofilm contact tank) in the latter stage mainly contains soluble BOD and ammonia nitrogen ( NH_Four-N) flows in, BOD reduction and nitrification are efficiently performed in the aerobic tank in the subsequent stage. In addition, since SS and suspended BOD do not flow into the aerobic tank in the subsequent stage, the number of washings for removing excess SS and the like adhering to the contact filter medium can be greatly reduced.
[0019]
In the latter aerobic tank, nitrification by nitrifying bacteria (nitrite bacteria, nitrate bacteria), etc. is performed, and NH_FourIs NO₂Or NO_ThreeIs converted to NO_ThreeN₂So-called denitrification, which reduces TN (total nitrogen amount) by removing it from water as a gas, does not proceed in this system because a high BOD and low DO (dissolved oxygen amount) environment is required. However, in this water purification system, the water treated in the latter aerobic tank is returned and circulated and returned to the anaerobic tank having a relatively low DO environment inside the contact filter medium with high BOD and SS adhered to the inflow raw water. Therefore, denitrification is also performed efficiently.
[0020]
Furthermore, when a contact filter medium having a large opening diameter of 1 to 20 mm is used, SS flocs are likely to adhere uniformly to the fiber surface, and there are sufficient gaps between the fibers. The inside can be uniformly passed without unevenness, and BOD can be reduced and denitrification can be performed efficiently. When a contact filter medium having an opening diameter of less than 1 mm is used, clogging occurs due to adhesion of the SS component, and in some cases, there is a risk of complete blockage. If it becomes like this, since raw | natural water and circulating water can only contact only the outer peripheral part of a contact filter medium, efficient organic matter reduction | decrease, denitrification, etc. by microorganisms etc. cannot be anticipated.
[0021]
In the case where no contact filter medium is used in the anaerobic tank, the SS component only accumulates as sludge on the bottom, so that it becomes completely anaerobic, and a septic odor such as hydrogen sulfide gas tends to be generated. In this case, the return circulating water also has less chances of contact with the SS, so that efficient denitrification is not performed.
[0022]
In the water purification system described above, most of the sludge is collected in the contact filter medium of the aerobic tank-anaerobic tank in the previous stage. The sludge is desorbed from the contact filter medium and deposited at the bottom of the tank by applying backwashing such as giving a strong aeration. The accumulated sludge may be removed by vacuum or the like.
[0023]
The accumulated sludge may be self-digested. In this case, two aerobic and anaerobic tanks in the previous stage are provided, and while the sludge of one system is self-digested, the inflow raw water and If the return circulating water is allowed to flow, sludge can be reduced without interrupting water purification, and the maintenance cost can be greatly reduced. Two aerobic and anaerobic tanks may have the same capacity or may have different capacities, both of which use a polyolefin-based non-woven fabric as a contact filter medium. It is desirable.
[0024]
As such a water purification system 1, for example, as shown in FIG. 3, the aerobic tank 2-anaerobic tank 3 of the first stage 4a of the first system and the aerobic tank 2-anaerobic tank 3 of the front stage 4b of the second system. And the aerobic tank 2 of the rear stage 5 are arranged in order and communicated, and the raw water 7 from the inflow path 6 and the circulating water from the circulation path 8 are directly connected to the aerobic tank 2-anaerobic tank 3 of the front stage 4b of the second system. In addition, a bypass is provided so that the purified treated water can be returned and circulated from the aerobic tank 2 of the rear stage 5 to the aerobic tank 2 of the front stage 4a of the first system.
[0025]
In this water purification system 1, as shown to Fig.4 (a), the aerobic tank 2-anaerobic tank 3 of the front | former stage 4a of the 1st system | strain, the aerobic tank 2-anaerobic tank 3 of the front | former stage 4b of the 2nd system | strain, and a back | latter stage The water is purified by circulating the treated water using the circulation path 8 while passing the water in the order of the five aerobic tanks 2. At this time, in the portion corresponding to the aerobic tank 2, the hatched portion of the drawing is aerated with an air diffuser or the like to keep the aerobic state. When operating for a certain period, due to the adhesion of SS and the growth of the biofilm, a large amount of sludge mainly adheres to the contact filter medium of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system.
[0026]
After a large amount of sludge adheres to the contact filter medium in the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a in the first system in this way, as shown in FIG. The circulating water from the second stage is passed through the aerobic tank 2-the anaerobic tank 3 of the front stage 4 b of the second system and the aerobic tank 2 of the rear stage 5 in this order, and the treated water is circulated using the circulation path 8. To purify. During this time, water is not passed through the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system, but the whole surface is aerated to remove sludge from the contact filter medium and to self-digest.
[0027]
After the sludge is removed from the contact filter medium and self-digested, as shown in FIG. 4 (c), the flow path is returned to the original position, and the aerobic tank 2 to the anaerobic tank 3 of the front stage 4b of the second system is completely aerated. Then, the sludge is removed from the contact filter medium and self-digested. In this state, most of the sludge adheres to the contact filter medium of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system. The aerobic tank 2-sludge in the anaerobic tank 3 can be self-digested.
[0028]
After purifying the raw water by the above-described treatment, sludge can be reduced while continuously purifying the water by repeating the treatments of FIGS. 4B and 4C.
[0029]
FIG. 5 shows another example using two aerobic tanks 2-anaerobic tanks 3 of the first stage 4, and the aerobic tank 2-anaerobic tank 3 and the second system of the first stage 4 a of the first system. The aerobic tank 2 of the front stage 4b and the anaerobic tank 3 are arranged side by side and are connected to the aerobic tank 2 of the rear stage 5 together with piping from the inflow path 6 through the flow path switching 10, respectively. Moreover, the circulation path 8 is provided so that the treated water 9 can be returned and circulated from the aerobic tank 2 of the rear stage 5 to the inflow path 6.
[0030]
In this water purification system 1, as shown in FIG. 6 (d), the water is first passed through the aerobic tank 2-the anaerobic tank 3 of the first stage 4 a and the aerobic tank 2 of the rear stage 5 in the first system, and the circulation path 8 is used to purify the water by circulating the treated water. At this time, in the portion corresponding to the aerobic tank 2 and indicated by diagonal lines, the aerobic state is maintained by aeration with an air diffuser or the like. When operating for a certain period of time, a large amount of sludge adheres to the contact filter medium of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system due to the adhesion of SS and the growth of the biofilm.
[0031]
After a large amount of sludge adheres to the contact filter media in the aerobic tank 2 to the anaerobic tank 3 in the first stage 4a of the first system, the flow path is switched to remove from the raw water 7 and the circulation path 8 as shown in FIG. The circulating water is passed through the aerobic tank 2 in the front stage 4b of the second system in the order 2 to the aerobic tank 2 in the rear stage 5 and the aerobic tank 2 in the rear stage 5, and the water is purified by circulating the treated water using the circulation path 8. . During this time, water is not passed through the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system, but the whole surface is aerated to remove sludge from the contact filter medium and to self-digest.
[0032]
After self-digestion, as shown in FIG. 6 (f), the flow path is returned to the original position, and water passes through the aerobic tank 2-the anaerobic tank 3 of the first stage 4 a and the aerobic tank 2 of the rear stage 5 in this order. In addition, the water is purified by circulating the treated water using the circulation path 8. During this time, water is not passed through the aerobic tank 2 to the anaerobic tank 3 of the first stage 4b of the second system, but the whole surface is aerated to remove sludge from the contact filter medium and to self-digest.
[0033]
After the raw water is treated in this way, the treatment of FIG. 6 (e) and FIG. 6 (f) is alternately repeated, whereby the aerobic tank 2-anaerobic tank 3 and the second system of the first stage 4a of the first system. By performing water purification and self-digestion alternately in the aerobic tank 2 and the anaerobic tank 3 of the front stage 4b, sludge can be reduced while continuously purifying water.
[0034]
FIG. 7 shows another example using two aerobic tanks 2 in the first stage 4 and an aerobic tank 3 in the first stage 4a of the first system of the water purification system shown in FIG. -It has the structure which provided the bypass from the exit part of the anaerobic tank 3 to the aerobic tank 2 of the back | latter stage 5.
In this example, by switching the flow path of each bypass, the flow of water is changed between the aerobic tank 2 of the first stage 4a of the first system 2 to the aerobic tank 3 of the first stage 4 and the aerobic tank 2 of the second stage 5 and the front stage 4b of the second system. The aerobic tank 2 can be switched to the anaerobic tank 3 and the aerobic tank 2 of the rear stage 5. The aerobic tank 2 to the anaerobic tank 3 of the front stage 4 of the first system and the second system are vertically arranged. Although the tanks are lined up, the manner of movement of the water in each tank is substantially the same as the case where the first aerobic tank 2 and the anaerobic tank 3 of the first stage 4 of FIG. .
[0035]
In this water purification system 1, as shown in FIG. 8 (g), first, the aerobic tank 2 of the first stage 4 a of the first system 2-the anaerobic tank 3 and the aerobic tank 2 of the second stage 5 are passed in this order, and the circulation path 8 is used to purify the water by circulating the purified water. At this time, in the portion corresponding to the aerobic tank 2, the hatched portion of the drawing is aerated with an air diffuser or the like to keep the aerobic state. When operating for a certain period of time, a large amount of sludge adheres to the contact filter medium of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system due to the adhesion of SS and the growth of the biofilm.
[0036]
After a large amount of sludge adheres to the contact filter medium of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system, the flow path is switched by the flow path switching 10 as shown in FIG. Circulating the circulating water from the circulation path 8 in the order of the aerobic tank 2 in the front stage 4b of the second system 2 to the anaerobic tank 3 in the second stage and the aerobic tank 2 in the rear stage 5 and circulating the treated water using the circulation path 8. To purify the water. During this time, water is not passed through the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system, but the whole surface is aerated to remove sludge from the contact filter medium and to self-digest.
[0037]
After removing the sludge from the contact filter medium and causing self-digestion, as shown in FIG. 8 (i), the flow path is returned to the original position, the first stage 4a aerobic tank 2-anaerobic tank 3, the rear stage 5 of the first system The water is purified by circulating water through the aerobic tank 2 in order and circulating the treated water using a circulation path. During this time, water is not passed through the aerobic tank 2 to the anaerobic tank 3 of the first stage 4b of the second system, but the whole surface is aerated to remove sludge from the contact filter medium and to self-digest.
[0038]
After the raw water is treated in this way, the treatment of FIG. 8 (h) and FIG. 8 (i) is alternately repeated, so that the aerobic tank 2-anaerobic tank 3 of the first stage 4a of the first system and the second system By performing water purification and self-digestion alternately in the aerobic tank 2 and the anaerobic tank 3 of the front stage 4b, sludge can be reduced while continuously purifying water.
[0039]
Hereinafter, the present invention will be described specifically by way of examples.
【Example】
Example 1
An average fiber diameter of 600 μm, a core-sheath composite fiber of which the core component is polypropylene and the sheath component is polyethylene are bonded to each other, the thickness is 50 mm, and the apparent density is 0.04 g / cm^ThreeA non-woven fabric was prepared. The average opening diameter obtained by projecting the surface of the nonwoven fabric was about 6 mm. This nonwoven fabric was cut into a width of 30 cm and a length of 100 cm to obtain a contact filter medium A.
An average fiber diameter of 300 μm, a core-sheath composite fiber of which the core component is polypropylene and the sheath component is polyethylene are bonded to each other, the thickness is 50 mm, and the apparent density is 0.05 g / cm.^ThreeA non-woven fabric was prepared. The average opening diameter obtained by projecting the surface of the nonwoven fabric was about 1.5 mm. This nonwoven fabric was cut into a width of 30 cm and a length of 100 cm to obtain a contact filter medium B.
250 g / m per unit area made of polyester fiber²4 pieces of 7 mm thick fiber-bonded non-woven fabric cut into a width of 8 cm are stacked, and continuously ultrasonically sealed in the longitudinal direction while compressing the central portion in the width direction, and 8 pieces of non-woven fabric pieces centering on the seal portion A rod-shaped non-woven fabric having a diameter of about 8 cm having a chrysanthemum-like cross section extending radially. This rod-shaped non-woven fabric was cut into a length of 30 cm to obtain a contact filter medium C.
A purification channel having a width of 30 cm, a depth of 30 cm, and a length of 50 m was prepared beside the domestic drainage channel. An aeration pipe for aeration is provided on the entire bottom surface of the region corresponding to each aerobic tank and anaerobic tank of the purification water channel, and the contact filter media A, B, and C are arranged as described below, and FIG. As shown in Fig. 1, a water purification system in which two upstream aerobic tanks-anaerobic tanks and downstream aerobic tanks were arranged side by side in the flow direction was obtained. In addition, the diffuser tube under the aerobic tank-anaerobic tank in the first two stages was set so that it can be turned on and off independently every 5 m.
As shown in FIG. 1, a region where the contact filter medium A11 and the contact filter medium B12 are arranged was used for the aerobic tank-anaerobic tank in the previous stage. First, in the previous aerobic tank, a region in which three contact filter media A11 are arranged at equal intervals in the width direction so that their surfaces are parallel to each other and parallel to the flow is 5 m in the flow direction (contact filter media A11 Are arranged and used in the flow direction. Next, in the anaerobic tank, an area in which the four contact filter media A11 are arranged at equal intervals in the width direction so that the surfaces thereof are parallel to each other and parallel to the flow is 4 m in the flow direction, and four contact filter media. A region in which B is arranged at equal intervals in the width direction so that the surfaces are parallel to each other and parallel to the flow is 1 m in the flow direction, and five contact filter media B12 are parallel to the flow and the surfaces are parallel to each other. The regions arranged at equal intervals in the width direction are sequentially provided so as to be 5 m in the flow direction. Here, the sum of the distances between the nonwoven fabrics in the width direction / the sum of the nonwoven fabric thicknesses is 15/15 × 100 = 100%, 10/20 × 100 = 50%, / 25 × 100 = 20%.
Further, in the aerobic tank in the subsequent stage, as shown in FIG. 2, the longitudinal direction of the rod-shaped nonwoven fabric of the contact filter medium C13 is the vertical direction, and the center of the contact filter medium C13 and the center of the contact filter medium C13 are in the width direction. An area arranged in a staggered manner by being suspended from the supporting bars so as to be arranged in a row at intervals of 10 cm and each row being spaced by 10 cm in the flow direction is used by providing 20 m in the flow direction.
The method for water purification of domestic wastewater using the above water purification system will be described below. In addition, arrangement | positioning and flow path of each tank of this water purification system are substantially the same as the water purification system demonstrated in FIG. 3, FIG.
First, the domestic waste water is pumped up at a flow rate of 10 liters / minute, and flows into the purification channel. As shown in FIG. 4 (a), the inflow water is obtained from the aerobic tank 2-anaerobic tank 3 of the first stage 4 a of the first system, the aerobic tank 2-anaerobic tank 3 of the front stage 4 b of the second system, and the rear stage 5. The water is passed through the air tank 2 in order and purified and discharged. A part of the treated water is circulated through the circulation path 8 to the inlet at a flow rate of 10 liters / minute. That is, the amount of inflow and outflow water is 10 liters / minute, and the flow rate in each tank of the water purification system 1 is 20 liters / minute. It should be noted that the area of 5 m from the inlet of the first system and the second system in the front stage 4 is aerated and aerobic to make the aerobic tank 2, and the remaining 10 m of the area is aerated and aerated. The anaerobic tank 2 is used as the anaerobic tank 2, and the aerobic tank 2 in the rear stage 5 is used in an aerobic state by aeration.
Table 1 shows the inflow raw water after the operation of the water purification system, the outlet of the aerobic tank 2-anaerobic tank 3 in the second stage 4b of the second system, and the quality of treated water. As is clear from Table 1, the SS value at the outlet of the aerobic tank 2 to the anaerobic tank 3 in the front stage 4b of the second system is very low, and the contact filter medium A11 and the contact filter medium in the front stage aerobic tank 2 to the anaerobic tank 3 It can be seen that B12 supplements most of the SS and suspension BOD components.
The nitrogen component is NH_Four-N (ammonia nitrogen) is non-toxic NO by digestive bacteria in the aerobic tank in the latter stage_ThreeConverted to -N (nitrate nitrogen), NO_Three-N is denitrified in the previous anaerobic tank by circulation return, and TN (total nitrogen: total nitrogen amount) is reduced to about half.
About one month after the operation, a large amount of sludge due to adhesion of SS, biofilm, etc. is attached to the contact filter media A11 and the contact filter media B12 of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system. As shown in FIG. 4 (b), the flow path is shut off so that the inflow water and the circulating water do not flow into the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system, and the bypass is bypassed. Is used to directly flow into the aerobic tank 2 to the anaerobic tank 3 of the front stage 4b of the second system. In this way, the aerobic tank 2 and the anaerobic tank 3 in the first stage 4a of the first system are switched so that both the aerobic tank 2 and the anaerobic tank 3 are aerated (total aeration) for 3 weeks. As a result of the operation, the sludge in the aerobic tank 2 to the anaerobic tank 3 in the first stage 4a of the first system was greatly reduced due to self-digestion.
In addition, the purification of the inflow water (domestic wastewater) during this period passes through the aerobic tank 2 in the front stage 4b of the second system 2 to the anaerobic tank 3 and the aerobic tank 2 in the rear stage 5 as shown in FIG. 4 (b). The water purification was carried out by circulating and returning a part of the effluent, and the same water purification effect as in FIG. 4A was obtained.
Next, as shown in FIG. 4 (c), the flow path of the water is returned to the original position, and aeration in the anaerobic tank 2-anaerobic tank 3 in the first stage 4a of the first system is stopped. 4b aerobic tank 2-aerobic tank 2 in anaerobic tank 3 Both aerobic tank 2 and anaerobic tank 2 were switched to aeration (total aeration) and operated for 3 weeks. Sludge in the anaerobic tank 3 has also decreased.
Thereafter, by alternately repeating the processes shown in FIGS. 4B and 4C, the aerobic tank 2 and the anaerobic tank 3 in the first stage 4 of the first system and the second system are clogged with sludge. It was possible to efficiently purify the water without causing it.
[0040]
[Table 1]

[0041]
Example 2
As shown in FIG. 5, the aerobic tank 2-anaerobic tank 3 in the first stage 4a of the first system and the aerobic tank 2-anaerobic tank 3 in the front stage 4b of the second system are arranged side by side, ) And the circulating water are directly connected to each of the pipes, and the flow path is switched so that only one of them flows. Moreover, the aerobic tank 2-the anaerobic tank 3 of the front | former stage 4 of each system | strain were piped so that each could send water to the aerobic tank 2 of the back | latter stage 5. Furthermore, a water purification system was formed by forming a circulation path so that a part of the treated water discharged from the aerobic tank 2 in the rear stage 5 could be circulated to the inflow port.
The aerobic tank 2 to the anaerobic tank 3 in the first stage 4 are the same as those in Example 1 except that a purification channel having a width of 30 cm, a depth of 30 cm, and a length of 15 m is used instead of the purification channel in Example 1. The contact filter medium A11 and the contact filter medium B12 were piped, and a diffuser tube was provided at the bottom. Further, the aerobic tank 2 in the rear stage 5 is also a contact filter medium in the same manner as in Example 1, except that a purification channel having a width of 30 cm, a depth of 30 cm, and a length of 20 m was used instead of the purification channel in Example 1. It was formed by piping C13 and providing a diffuser tube at the bottom. A method for purifying domestic wastewater using this water purification system will be described below. First, the domestic wastewater is pumped up at a flow rate of 10 liters / minute and flows into the purification channel. As shown in FIG. 6 (d), the inflow water flows into only the aerobic tank 2-the anaerobic tank 3 of the first stage 4 a of the first system, and is purified and flows out through the aerobic tank 2 of the subsequent stage 5. . Part of the purified water is returned and circulated through the circulation path to the inlet at a flow rate of 10 liters / minute. That is, the amount of inflow and outflow water is 10 liters / minute, and the flow rate in each tank of the water purification system is 20 liters / minute. In addition, the area of 5 m from the inlet of the first system in the preceding stage is aerated to be in an aerobic state to be an aerobic tank 2, and the remaining 10 m area is to be anaerobic without being aerated and used as an anaerobic tank 3. The aerobic tank 2 in the rear stage 5 is used by aeration of the whole.
Table 2 shows the inflow raw water after operation of the water purification system, the aerobic tank 2 of the first stage 4a of the first system, the outlet of the anaerobic tank 3, and the water quality data of the treated water. As is clear from Table 2, the SS value at the outlet of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4a of the first system is very low, and the contact filter medium A11 of the aerobic tank 2 to the anaerobic tank 3 of the first stage 4 It can be seen that the filter medium B12 supplements most of the SS and suspension BOD components. The nitrogen component is NH_Four-N (ammonia nitrogen) is non-toxic NO by digestive bacteria in the aerobic tank in the latter stage_ThreeConverted to -N (nitrate nitrogen), NO_Three-N is denitrified in the previous anaerobic tank by circulation return, and TN (total nitrogen: total nitrogen amount) is reduced to about half.
About one month after the operation, a large amount of sludge is adhered to the contact filter medium A11 and the contact filter medium B12 of the first stage aerobic tank-anaerobic tank of the first system due to adhesion of SS, biofilm, and the like. Therefore, as shown in FIG. 6E, the flow path is switched by switching the flow path so that the inflowing raw water and the circulating water do not flow into the aerobic tank-anaerobic tank of the first stage 4a of the first system, It is made to flow into the aerobic tank 2-the anaerobic tank 3 of the front | former stage 4b of a system | strain. In this way, the aerobic tank 2 and the anaerobic tank 3 in the first stage 4a of the first system are switched so that both the aerobic tank 2 and the anaerobic tank 3 are aerated (total aeration) for 3 weeks. As a result of the operation, the sludge in the aerobic tank 2 to the anaerobic tank 3 in the first stage 4a of the first system was greatly reduced due to self-digestion.
In addition, the purification of the inflow water (domestic wastewater) during this period passes through the aerobic tank 2 in the front stage 4b of the second system 2 to the anaerobic tank 3 and the aerobic tank 2 in the rear stage 5 as shown in FIG. 6 (e). This is done by irrigating and circulating part of the effluent. Here, the area of 5 m from the inlet of the second system is aerated to make an aerobic state, and the remaining 10 m area is made anaerobic without aeration and used as an anaerobic tank. The aerobic tank 2 is used by aeration of the entire aerobic tank. The water quality at the outlet of the aerobic tank 2 in the front stage 4b of the second system was examined. As a result, the aerobic tank 2 in the front stage 4a of the first system in the case of FIG. The water quality at the outlet was exactly the same, and the water purification effect was also the same.
Next, as shown in FIG. 6 (f), the flow path is switched by the flow path switching 10 so that the inflow raw water and the circulating water do not flow into the aerobic tank 2 to the anaerobic tank 3 of the front stage 4b of the second system, Directly flow into the aerobic tank 2-anaerobic tank 3 of the first stage 4a of the first system, and return the water flow path to the original. Stop aeration in the anaerobic tank 2-anaerobic tank 3 of the first stage 4a of the first system, and both the aerobic tank 2 and the anaerobic tank 3 of the aerobic tank 2-anaerobic tank 3 of the second stage 4b As a result of switching to aeration (total aeration) and operating for 3 weeks, sludge in the aerobic tank 2 to the anaerobic tank 3 in the second stage 4b of the second system was also greatly reduced due to self-digestion.
Thereafter, by alternately repeating the processes of FIG. 6 (e) and FIG. 6 (f), the aerobic tank 2 to the anaerobic tank 3 of the first stage 4 of either the first system or the second system is clogged with sludge. It was possible to efficiently purify the water without causing it. In the water purification system of this example, even when the flow path was changed in order to perform self-digestion of sludge, a substantially uniform water purification effect was always obtained.
[0042]
[Table 2]

[0043]
【The invention's effect】
The contact filter medium used in the water purification system of the present invention is a nonwoven fabric made of polyolefin fibers, in particular, by controlling the pore diameter and thickness of the polyolefin nonwoven fabric, moderate SS adheres to the fiber surface and is completely In order to prevent clogging between the fibers, water constantly flows through the inside of the nonwoven fabric, the contact area of the biofilm increases substantially, and as a contact filter medium, particularly a contact filter medium for treating wastewater having a large amount of SS and BOD. Are suitable.
In addition, since a large amount of SS or biofilm has adhered too much and it is desired to remove the attached SS or biofilm and return to the original porous structure, the SS or biofilm can be easily peeled off by light vibration or aeration from below. So you can easily put it back.
Therefore, in the water purification system of the present invention, when a large amount of organisms adhere too much and it is desired to return to the original porous structure, the SS and the biofilm are easily separated by light vibration or aeration from below, Since it can be returned, it is particularly suitable for purification of water containing a large amount of SS and BOD to be removed.
The water purification system of the present invention is suitable for household wastewater, rural village wastewater, community household wastewater, urban rivers, campsite household wastewater, food factory wastewater purification, pond and dam purification.
[Brief description of the drawings]
FIG. 1 is a schematic view of one system of an aerobic tank and an anaerobic tank in the first stage of this invention as seen from above.
FIG. 2 is a schematic view of the latter aerobic tank of the present invention as seen from above.
FIG. 3 shows an example of a water purification system for an aerobic tank-anaerobic tank-aerobic tank of the present invention.
FIG. 4 is a diagram for explaining the flow of water as an example of a water purification system.
FIG. 5 shows another example of the water purification system of the aerobic tank-anaerobic tank-aerobic tank of the present invention.
FIG. 6 is a diagram for explaining the flow of water in another example of the water purification system.
FIG. 7 shows another example of the water purification system of the aerobic tank-anaerobic tank-aerobic tank of the present invention.
FIG. 8 is a diagram for explaining the flow of water in another example of the water purification system.
FIG. 9 shows another example of the water purification system for the aerobic tank-anaerobic tank-aerobic tank of the present invention.
[Explanation of symbols]
1 Water purification system
2 Aerobic tank
3 Anaerobic tank
4 First stage
4a First stage of the first system
4b First stage of the second system
5 Second stage
6 Inflow channel
7 Raw water
8 Circuits
9 treated water
10 Channel switching
11 Contact filter media A
12 Contact filter media B
13 Contact filter medium C

Claims

The front aerobic tank-anaerobic tank-the latter aerobic tank, and (the front aerobic tank-anaerobic tank) are composed of two systems, and at least one tank uses a contact filter medium made of a nonwoven fabric of polyolefin fibers. A water purification system,
The first system (front aerobic tank-anaerobic tank), the second system (front aerobic tank-anaerobic tank) and the rear aerobic tank are arranged in series in this order, and the first system ( An inflow path is arranged so that raw water flows into the inlet of the previous aerobic tank-anaerobic tank), a circulation path is provided to return the water treated in the subsequent aerobic tank to the inflow path, and from the inflow path A bypass capable of switching the flow path is provided so that the raw water and the circulating water from the circulation path can be sent directly to the inlet of the second system (previous aerobic tank-anaerobic tank). When raw water and circulating water flow into the (aerobic tank-anaerobic tank), other systems (previous aerobic tank-anaerobic tank) self-digest sludge by aeration in both the aerobic tank and the anaerobic tank In this way, the water purification system is arranged so that inflow of raw water and circulating water and self-digestion by aeration are alternately performed. .

2. The water purification system according to claim 1, further comprising a bypass extending from an outlet portion of the first system (front aerobic tank-anaerobic tank) to an inlet portion of a rear aerobic tank.

The front aerobic tank-anaerobic tank-the latter aerobic tank, and (the front aerobic tank-anaerobic tank) are composed of two systems, and at least one tank uses a contact filter medium made of a nonwoven fabric of polyolefin fibers. A water purification system,
The first system (previous aerobic tank-anaerobic tank) and the second system (previous aerobic tank-anaerobic tank) are arranged in parallel, and each system (previous aerobic tank-anaerobic tank). An inflow path is arranged through the channel switching means so that raw water flows into the system, and each system's (previous aerobic tank-anaerobic tank) is connected to the subsequent aerobic tank and processed in the subsequent aerobic tank If a circulation path is provided to return the discharged water to the inflow path, and raw water and circulating water are flowing into (anterior aerobic increase-anaerobic tank) of one system, the other system (anterior aerobic tank) -Anaerobic tank) is characterized in that sludge is self-digested by aeration in both aerobic tank and anaerobic tank, and the inflow of raw water and circulating water and self-digestion by aeration are performed alternately. Water purification system.

An aerobic tank at the front stage-an anaerobic tank-an aerobic tank at the rear stage, and a device comprising two systems (the previous aerobic tank-anaerobic tank), and a contact filter medium comprising a nonwoven fabric of polyolefin fibers in at least one tank A water purification method using
The first system (front aerobic tank-anaerobic tank), the second system (front aerobic tank-anaerobic tank) and the rear aerobic tank are arranged in series in this order, and the first system ( An inflow path is arranged so that raw water flows into the inlet of the previous aerobic tank-anaerobic tank), a circulation path is provided to return the water treated in the subsequent aerobic tank to the inflow path, and from the inflow path A bypass capable of switching the flow path is provided so that the raw water and the circulating water from the circulation path can be sent directly to the inlet of the second system (previous aerobic tank-anaerobic tank). When raw water and circulating water flow into the (aerobic tank-anaerobic tank), other systems (previous aerobic tank-anaerobic tank) self-digest sludge by aeration in both the aerobic tank and the anaerobic tank Thus, a water purification method characterized by alternately performing inflow of raw water and circulating water and self-digestion by aeration.

The water purification method of Claim 1 using the apparatus which further provided the bypass from the exit part of the 1st system (front aerobic tank-anaerobic tank) to the inlet part of a subsequent aerobic tank.

An aerobic tank at the front stage-an anaerobic tank-an aerobic tank at the rear stage, and a device comprising two systems (the previous aerobic tank-anaerobic tank), and a contact filter medium comprising a nonwoven fabric of polyolefin fibers in at least one tank A water purification method using
The first system (previous aerobic tank-anaerobic tank) and the second system (previous aerobic tank-anaerobic tank) are arranged in parallel, and each system (previous aerobic tank-anaerobic tank). An inflow path is arranged through the channel switching means so that raw water flows into the system, and each system's (previous aerobic tank-anaerobic tank) is connected to the subsequent aerobic tank and processed in the subsequent aerobic tank If the raw water and the circulating water flow into the previous system (previous aerobic tank-anaerobic tank), the other system (previous aerobic) (Tank-anaerobic tank) is a water purification method characterized in that sludge is self-digested by aeration in both an aerobic tank and an anaerobic tank, and inflow of raw water and circulating water and self-digestion by aeration are performed alternately.