JP2004188379A

JP2004188379A - Sludge treatment apparatus

Info

Publication number: JP2004188379A
Application number: JP2002362375A
Authority: JP
Inventors: Shigemi Usui; 慈美臼井; Shinichiro Fuchigami; 真一郎淵上; Takashi Sakakibara; 隆司榊原
Original assignee: Panasonic Environmental Systems and Engineering Co Ltd; Matsushita Ecology Systems Co Ltd
Current assignee: Panasonic Ecology Systems Co Ltd; Panasonic Environmental Systems and Engineering Co Ltd
Priority date: 2002-12-13
Filing date: 2002-12-13
Publication date: 2004-07-08
Anticipated expiration: 2022-12-13
Also published as: JP4519401B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge treatment apparatus which can optimize ultrasonic irradiation, perform efficient treatment, and extend the life span of an ultrasonic transducer. <P>SOLUTION: In the sludge treatment apparatus, a part of sludge is introduced into an ultrasonic treatment device in the biological treatment of waste water, and the sludge which has been subjected to ultrasonic treatment in the ultrasonic treatment device is transferred to a biological treatment tank using a biological method. In the ultrasonic treatment device, ultrasonic irradiation time per hour is determined, and an ultrasonic wave is oscillated periodically based on the determined irradiation time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、排水処理により発生する汚泥中の有機物の大幅な減量を可能とする汚泥処理装置に関する。
【０００２】
【従来の技術】
従来の汚泥減量化技術には、生物・化学的汚泥処理と、物理的汚泥処理があり、生物・化学的汚泥処理は化学薬品等を使用し短時間（８時間程度）で処理するもので大容量の汚泥処理に向いており、物理的汚泥処理は超音波等を利用して長時間（２４時間程度）を掛けて処理するもので小容量の汚泥処理に向いている（特許文献１、特許文献２参照）。そして例えば特許文献２の処理技術では、有機性汚水を好気性生物処理槽で処理し、沈殿槽で固液分離して処理水と汚泥とを得る。この汚泥を返送汚泥として好気性生物処理槽に循環するとともに、一部を余剰汚泥として貯留槽に導入する。貯留槽ではその汚泥を超音波発振子から発振される超音波を用いて可溶化処理を行い、可溶化汚泥として好気性生物処理槽に返して生物分解を行うことにより、汚泥を減容する方法が開示されている。
【０００３】
【特許文献１】
特開平５−３４５１９２号公報
【特許文献２】
特開平１１−１２８９７５号公報
【０００４】
【発明が解決しようとする課題】
しかし、上記従来の超音波発振装置は、生物処理槽への負荷を考慮した運転を提案するものではなく、超音波振動子の長寿命化、低消費電力でコンパクトな装置を図ることは提案されていない。
【０００５】
そこで、本発明は、超音波照射の適正化を図り、処理効率がよく超音波振動子の長寿命化を図ることのできる装置を提供することを目的とする。
特に、本発明は、生物処理槽への負荷を考慮した運転を実現することで省エネルギーと超音波振動子の長寿命化を実現することを目的とする。
また、本発明は、低消費電力でコンパクトな装置を実現することを目的とする。
【０００６】
【課題を解決するための手段】
請求項１記載の本発明の汚泥処理装置は、排水の生物処理法において、汚泥の一部を超音波処理装置に導入し、前記超音波処理装置にて超音波処理した前記汚泥を生物処理法による生物処理槽に移送する汚泥処理装置であって、前記超音波処理装置では、単位時間当たりの超音波照射時間を決定し、決定した照射時間に基づいて周期的に超音波を発振することを特徴とする。
請求項２記載の本発明は、請求項１に記載の汚泥処理装置において、前記超音波処理装置に導入する汚泥の流量と超音波振動子の定格出力及び超音波照射レベルとから定格超音波照射量を算出し、指示された超音波照射量となるように前記超音波照射時間を決定することを特徴とする。
請求項３記載の本発明は、請求項１に記載の汚泥処理装置において、一日を複数の時間帯に区分して、それぞれの時間帯によって前記超音波照射時間を異ならせることを特徴とする。
請求項４記載の本発明の超音波処理装置は、排水の生物処理法において、汚泥の一部を導入し、超音波処理した汚泥を生物処理法による生物処理槽に移送する超音波処理装置であって、超音波振動子をそれぞれ備えた超音波処理槽を複数備え、それぞれの前記超音波処理槽を、高低差を持たせて配置し、汚泥を上方に位置する前記超音波処理槽から順に下方に位置する前記超音波処理槽に流出することを特徴とする。
請求項５記載の本発明の超音波処理装置は、排水の生物処理法において、汚泥の一部を導入し、超音波処理した汚泥を生物処理法による生物処理槽に移送する超音波処理装置であって、超音波処理槽に超音波振動子と紫外線照射手段とを備え、前記紫外線照射手段を前記超音波振動子よりも汚泥の下流側に配置したことを特徴とする。
請求項６記載の本発明の超音波処理槽は、排水の生物処理法において、汚泥の一部を導入し、超音波処理した汚泥を生物処理法による生物処理槽に移送する超音波処理槽であって、第１の槽と第２の槽を堰によって区分し、前記第１の槽に汚泥の流入口と超音波振動子を備え、前記第２の槽に汚泥の流出口を備え、前記超音波振動子を前記堰の下方に、その放射面が鉛直方向と平行に向くように取り付けられ、前記超音波振動子の取り付けられた面と対向する反射壁に前記流入口を設けたことを特徴とする。
請求項７記載の本発明は、請求項６に記載の超音波処理槽において、前記紫外線照射手段を、前記堰を越える汚泥を照射する位置に配置したことを特徴とする。
請求項８記載の本発明は、請求項６に記載の超音波処理槽において、前記紫外線照射手段を、直管型又はＵ字管型の紫外線ランプで構成し、当該紫外線ランプの長手方向を前記堰の方向としたことを特徴とする。
請求項９記載の本発明は、請求項６に記載の超音波処理槽において、前記堰を、前記第１の槽又は前記第２の槽の内壁全幅に渡って設けたことを特徴とする。
請求項１０記載の本発明は、請求項６に記載の超音波処理槽において、前記流入口を、前記超音波振動子の高さ方向に下部から１／３以下の位置に設けたことを特徴とする。
請求項１１記載の本発明は、請求項６に記載の超音波処理槽において、前記流入口を、前記第１の槽の底面から前記堰までの高さの１／３以下の位置に設けたことを特徴とする。
【０００７】
【発明の実施の形態】
本発明の第１の実施の形態による汚泥処理装置は、単位時間当たりの超音波照射時間を決定し、決定した照射時間に基づいて周期的に超音波を発振するものである。本実施の形態によれば、汚泥中の生物活動状態に応じた超音波を照射するとともに、連続的な照射と比較して超音波振動子の長寿命化を図ることができ、また長期の停止期間を避け、周期的な運転を行うことで、超音波振動子の放射面に汚泥が付着したり、処理槽底面に汚泥が沈殿することを防止でき、超音波振動子の故障原因を避けることができる。
本発明の第２の実施の形態は、第１の実施の形態による汚泥処理装置において、超音波処理装置に導入する汚泥の流量と超音波振動子の定格出力及び超音波照射レベルとから定格超音波照射量を算出し、指示された超音波照射量となるように超音波照射時間を決定するものである。本実施の形態によれば、汚泥の流量に応じた適正な照射量を決定することができる。
本発明の第３の実施の形態は、第１の実施の形態による汚泥処理装置において、一日を複数の時間帯に区分して、それぞれの時間帯によって超音波照射時間を異ならせるものである。例えば流入する排水が生活系排水である場合、排水の量は家庭の生活サイクルによって増減するため、生物処理槽への負荷も家庭の生活サイクルに応じて変化するが、本実施の形態によれば、例えば生物処理槽への負荷が大きくなる早朝〜深夜は超音波振動子を「強運転モード」で運転し、生物処理槽への負荷が小さくなる深夜〜早朝は超音波振動子を「弱運転モード」で運転することで、省エネルギーと超音波振動子の長寿命化を実現することができる。
本発明の第４の実施の形態による超音波処理装置は、超音波振動子をそれぞれ備えた超音波処理槽を複数備え、それぞれの超音波処理槽を、高低差を持たせて配置し、汚泥を上方に位置する超音波処理槽から順に下方に位置する超音波処理槽に流出するものである。本実施の形態によれば、ポンプなどの動力源を使わずに重力で装置内を流れるため、低消費電力でコンパクトな装置を実現でき、既設の排水処理施設に取り付ける場合にも適する。
本発明の第５の実施の形態による超音波処理装置は、超音波処理槽に超音波振動子と紫外線照射手段とを備え、紫外線照射手段を超音波振動子よりも汚泥の下流側に配置したものである。本実施の形態によれば、汚泥に対して超音波処理と紫外線照射処理を組み合わせることで、汚泥の処理効率を高めることができるため、紫外線照射を活用して超音波振動子の運転時間や出力をできるだけ低いレベルで運転し、低消費電力と超音波振動子の長寿命化を達成することができる。
本発明の第６の実施の形態による超音波処理槽は、第１の槽と第２の槽を堰によって区分し、第１の槽に汚泥の流入口と超音波振動子を備え、第２の槽に汚泥の流出口を備え、超音波振動子を堰の下方に、その放射面が鉛直方向と平行に向くように取り付けられ、超音波振動子の取り付けられた面と対向する反射壁に流入口を設けたものである。本実施の形態によれば、超音波放射面の対面から汚泥を流入することで、流入した汚泥は超音波放射面に平行で１／４波長の整数倍の間隔でできる定在波によるキャビテーションの中を通過するため均一で効率の良い超音波処理ができる。
本発明の第７の実施の形態は、第６の実施の形態による超音波処理槽において、紫外線照射手段を、堰を越える汚泥を照射する位置に配置したものである。本実施の形態によれば、超音波処理を済ませた汚泥に対して効率的に紫外線照射を行うことができる。
本発明の第８の実施の形態は、第６の実施の形態による超音波処理槽において、紫外線照射手段を、直管型又はＵ字管型の紫外線ランプで構成し、当該紫外線ランプの長手方向を堰の方向としたものである。本実施の形態によれば、堰を乗り越える汚泥に対して均一に紫外線照射を行うことができる。
本発明の第９の実施の形態は、第６の実施の形態による超音波処理槽において、堰を、第１の槽又は第２の槽の内壁全幅に渡って設けたものである。本実施の形態によれば、堰による汚泥の対流を防止でき、スムーズな流れを実現するとともに、紫外線照射を効率的に行うことができる。
本発明の第１０の実施の形態は、第６の実施の形態による超音波処理槽において、流入口を、超音波振動子の高さ方向に下部から１／３以下の位置に設けたものである。
また本発明の第１１の実施の形態は、第６の実施の形態による超音波処理槽において、流入口を、第１の槽の底面から堰までの高さの１／３以下の位置に設けたものである。
これらの実施の形態によれば、槽の下層では流入する汚泥の勢いで撹拌が行われ、槽の中・上層では超音波振動子から発生する直進流及び超音波の進行方向に発生する音響放射圧によって、槽の中層に振動子から反射壁へ向かう流れが生じ、この反射壁へ向かう流れが反射することで、槽内が撹拌され、反射壁から堰へと向かって汚泥を押し流す強い水面の流れが発生する。また、槽内に撹拌装置などを取り付けることなく、良好な流動状態を実現できる。
【０００８】
【実施例】
以下、本発明による実施例の汚泥処理装置について、図面を参照して説明する。図１と図２は、本発明による一実施例の汚泥処理装置を示すブロック構成図である。
図１に示すように排水処理施設は、排水を溜める調整槽１と、有機物を微生物によって処理する生物処理槽２と、生物処理槽２で処理した汚水を重力によって汚泥と水に分離する沈殿槽３と、沈殿槽３で分離させた汚泥を導入する汚泥貯留槽４と、超音波処理を施す超音波処理装置５から構成されている。
排水は、下水管を通って排水処理施設に流入する。流入した排水は、調整槽１に一旦滞留し、一定量が生物処理槽２へ流入し、生物処理槽２で繁殖した微生物（以下、一例として活性汚泥と呼ぶ）によって浄化される。生物処理槽２への流入量に応じて、活性汚泥は沈殿槽３へ流入し、重力によって余剰汚泥と処理水に分離される。分離された汚泥の一部は返送汚泥として生物処理槽２へ返送され、他は超音波処理装置５にて超音波処理を行った上で、再度生物処理槽２へ流入し、残りは余剰汚泥として汚泥貯留槽に移される。
【０００９】
図２は図１における生物処理槽２を第一生物処理槽２Ａとし、同様に図１における汚泥貯留槽４を第二生物処理槽４Ａとして構成されている。
排水は、下水管を通って排水処理施設に流入する。流入した排水は、調整槽１に一旦滞留し、一定量が第一生物処理槽２Ａへ流入し、第一生物処理槽２Ａで繁殖した活性汚泥によって浄化される。第一生物処理槽２Ａへの流入量に応じて、活性汚泥は沈殿槽３へ流入し、重力によって余剰汚泥と処理水に分離される。余剰汚泥の一部は返送汚泥として第一生物処理槽２Ａへ返送され、残りは第二生物処理槽４Ａへ移され、超音波処理装置５にて超音波処理を行った上で、再度第二生物処理槽へ流入する。第二生物処理槽には必要に応じて、汚泥中の水分を除去するために、例えば膜分離装置を設置し、膜透過水は調整槽に流入する。なお、膜透過水は曝気槽に流入させてもよいし、そのまま放流することも可能である。また、膜分離装置は第二生物処理槽の外部に設置してもよい。
【００１０】
次に、超音波処理装置の制御方法について図３から図６を用いて説明する。
図３は、本発明の一実施例による超音波処理装置の一部の構成を示す概略図である。
余剰汚泥の一部は、流量制御弁１１を通って超音波処理槽５０に導入される。この導入される汚泥の量は流量計１２によって計測される。制御部１３は、流量計１２によって計測された流量が入力され、流量制御弁１１と超音波振動子１４を制御する。なお、これは一例であって、定量ポンプを用いてもよい。
【００１１】
図４は、本発明の一実施例による超音波処理装置の制御方法を示すフローチャートである。
まず、余剰汚泥発生量（Ａ［Ｌ／ｄａｙ］）を入力する（Ｓ１）。また、超音波照射レベル（Ｃ［％］定格比）を入力する（Ｓ２）。
入力された余剰汚泥発生量に基づいて処理流量（Ｑ［Ｌ／ｍｉｎ］＝Ｋ×Ａ÷（２４×６０））が制御部１３において計算される（Ｓ３）。ここで、Ｋは処理倍数であり、１〜１０、好ましくは２〜５倍とする。
流量計１２によって流量が計測され（Ｓ４）、Ｓ３で算出された処理流量となるように、制御部１３は流量制御弁１１を調整する（Ｓ５）。
そして制御部１３は、流量（Ｑ）、超音波振動子１４の定格出力（Ｐ［Ｗ］）、及び超音波照射レベル（Ｃ［％］）から超音波照射量（Ｐｃ＝０．０１・Ｃ・（Ｐ・Ｖ）／（６０・Ｑ）［Ｗｈ］）を算出する（Ｓ６）。なお、Ｖ［Ｌ］は超音波照射槽の体積、Ｖ／Ｑ（［ｍｉｎ］）は汚泥の超音波照射槽への滞留時間、（Ｐ・Ｖ）／（６０・Ｑ）（［Ｗｈ］）は定格超音波照射量である。
超音波振動子１４の運転モードとして、強運転モードと弱運転モードとを備える場合には、弱運転モードでの超音波処理の時間を、強運転の１０％〜５０％として、生物処理槽２の余力で汚泥を分解し、超音波振動子の長寿命化を図ることが好ましい。
制御部１３は、指示された超音波照射量となるように超音波振動子１４の運転時間を決定する（Ｓ７）。
【００１２】
図５は、本発明の一実施例による超音波処理装置の制御パターンを示すタイムチャートである。
生物処理槽２へ流入する排水の量は家庭の生活サイクルによって増減するため、生物処理槽２への負荷も家庭の生活サイクルに応じて変化する。図４に生物処理槽２への排水流入量の時間変化を示す。同図に示すように、早朝〜深夜と深夜〜早朝とに大別することができる。
従って本実施例では、生物処理槽２への負荷が大きくなる早朝〜深夜は超音波振動子１４を「強運転モード」で運転し、生物処理槽２への負荷が小さくなる深夜〜早朝は超音波振動子１４を「弱運転モード」で運転することで、省エネルギーと超音波振動子１４の長寿命化を実現することができる。
例えば、超音波振動子の定格出力（Ｐ［Ｗ］）と超音波照射量（Ｐｃ［Ｗｈ］）より決定される超音波照射時間（Ｔ［ｍｉｎ］）は、強運転モード（早朝〜深夜の場合）ではＴ＝（Ｐｃ／Ｐ）・６０［ｍｉｎ］とし、弱運転モード（深夜〜早朝の場合）では０．１Ｔ〜０．５Ｔとする。
ここで、１時間以内のサイクルで超音波振動子１４の運転をＯＮ−ＯＦＦすることが好ましい。例えば数時間に１回、流量やその他濁度を計測し、超音波振動子１４の運転時間をＯＮ−ＯＦＦするようにした場合、超音波振動子１４の放射面に汚泥が付着し、超音波振動子１４の故障の原因となる。また、超音波処理槽５０の底面に汚泥が沈殿してしまうことがある。
【００１３】
図６は、本発明の一実施例による超音波処理装置の操作方法を示すフローチャートである。本操作は主にユーザが操作するが、汚泥の発生量のデータを施設側から受信して、自動で処理することもできる。
まず、排水処理施設の運転管理データから汚泥の発生量（Ｌ／ｄａｙ）を確認（受信）する（Ｓ１１）。
そして、超音波処理装置５に汚泥の発生量と超音波照射レベルを指示（出力）（最初は５０％）する（Ｓ１２）。
Ｓ１２の指示（出力）後、運転を開始してから所定期間（例えば２〜４週間）後に汚泥の発生量を確認する（Ｓ１３）。確認の結果、汚泥の発生量が減少していれば超音波照射レベルを維持し（Ｓ１４）、汚泥の発生量に変化がないか、又は汚泥の発生量が増加している場合には超音波照射レベルを上げる（Ｓ１５）。このように汚泥の発生量や生物処理槽２の負荷に応じて照射量を制御する。例えば生物処理槽２への負荷が大きくなる早朝〜深夜は超音波振動子１４を「強運転モード」で運転し、生物処理槽２への負荷が小さくなる深夜〜早朝は超音波振動子１４を「弱運転モード」で運転することで、省エネルギーと超音波振動子の長寿命化を実現することができる。
【００１４】
次に、超音波処理装置の全体構成について図７を用いて説明する。
図７は、本発明の一実施例による超音波処理装置の全体構成を示す概略図である。
本実施例の超音波処理装置５は、小流量でも流れが安定するように、装置本体の下方に汚泥取入口６が配置され、汚泥はこの汚泥取入口６から一旦装置本体の上部に移動され、上部から下方に移動するにしたがって汚泥は処理され、装置本体下部に設けた汚泥返送口７から排出される。汚泥を汚泥取入口６から装置本体の上部に移動させる配管には、流量制御弁１１、流量計１２、濁度計１５を配置している。一方、汚泥を装置本体上部から汚泥返送口７に移動させる配管には、２つの超音波処理槽５０Ａ、５０Ｂを配置している。そして汚泥は、上部に配置された超音波処理槽５０Ａで処理された後に、超音波処理槽５０Ａよりも下方に配置された超音波処理槽５０Ｂで処理され汚泥返送口７に導かれる。
超音波処理装置５は、超音波処理槽５０にあわせて超音波発信器１６Ａ、１６Ｂが設けられ、超音波発信器１６Ａは超音波処理槽５０Ａに設置された超音波振動子１４Ａを発信させ、超音波発信器１６Ｂは超音波処理槽５０Ｂに設置された超音波振動子１４Ｂを発信させる。超音波処理槽５０Ａと超音波処理槽５０Ｂとの間の連絡管には脱気パイプ１８を用いる。開閉弁１７は、装置本体内の汚泥を排出する場合に用いられる。
【００１５】
本実施例の超音波処理装置５では、最上段の超音波処理槽５０Ａへ取り込まれた汚泥は、ポンプなどの動力源を使わずに重力で装置内を流れ、排水処理施設へ返送することができる。超音波処理槽５０が２槽以上の場合には、超音波処理槽５０を上下方向に高低差を持たせて配置することが好ましい。
本実施例の超音波処理装置５は、上記のような超音波処理槽５０の配置や配管構成とすることで、低消費電力でコンパクトな装置を実現でき、既設の排水処理施設に取り付ける場合にも適するものである。
【００１６】
次に、超音波処理装置の処理槽について図８から図１２を用いて説明する。
図８は本発明の一実施例による超音波処理装置の処理槽の構成を示す側面図、図９は同処理槽の上面図である。
超音波処理槽５０は、その内部に第１の槽５１と第２の槽５２とを備え、第１の槽５１と第２の槽５２とは、堰５３によって区画され、第１の槽５１内の汚泥は、この堰５３を越えて第２の槽５２に導かれる構成となっている。堰５３の幅は第１の槽５１又は第２の槽５２の内壁間に設け、内壁全幅に設けることが好ましい。
第１の槽５１の、堰５３側の面には超音波振動子１４がその放射面が鉛直方向と平行に向くように取り付けられ、この超音波振動子１４の取り付けられた面と対向する面（反射壁）に汚泥の流入口５４が設けられている。一方第２の槽５２の下部には汚泥を排出する流出口５５が設けられている。また第１の槽５１の底面には、第１の槽５１の底面に沈殿した汚泥を排出するドレイン口５６を設けている。汚泥は、超音波振動子１４の取り付け面の上方の堰５３によって、超音波振動子１４の上方から、堰５３によって一定の水位を保って溢れさせる。
ここで、流入口５４は、超音波振動子１４の高さ方向に、下部から１／３以下の位置に設ける。また、第１の槽５１の底面から堰５３までの高さの１／３以下の位置に設ける。そしてこの流入口５４は、第１の槽５１内に波長λ以下の長さの突出部を形成して取り付けることが好ましい。なお、超音波の発振周波数をｆ［Ｈｚ］、水中の音速をａ［ｍ／ｓ］とした時の超音波の波長λ［ｍ］は、λ＝ａ／ｆ［ｍ］である。
堰５３よりも上方位置の第２の槽５２には、紫外線照射手段であるＵＶ灯２０を取り付けている。このＵＶ灯２０は直管型又はＵ字管型であり、その中心軸が堰５３と平行になるように取り付ける。
ＵＶ灯２０を第２の槽５２に設けることで、汚泥は超音波照射が行われた後にＵＶ灯２０によって照射される。また汚泥へのＵＶ照射は、堰５３を流下する際と、排出口へ滞留した際に行われる。
【００１７】
本実施例は上記構成によって、汚泥に対してまず超音波照射が行われ、超音波によって汚泥のフロックが分散・破砕し、汚泥粒子に光のあたる表面積が増加する。また汚泥は、堰５３によって薄く伸ばされ、堰５３を越えた後も堰５３の表面をつたって薄く伸ばされながら流下する。更に流下した流れは薄く伸ばされた状態で流出口へ向けて流れる。ＵＶ灯２０は、薄く伸ばされた汚泥に対して紫外線があたるように取り付けられているため、濁度が大きい汚泥であっても全量に対して均一に紫外線を照射することができる。このように汚泥は均一にＵＶを吸収するため、汚泥細胞が十分に破壊する。
なお、ＵＶ灯２０の点灯時間を積算し、定格の寿命時間に達するとＵＶ灯２０の交換をユーザに促す表示機構を備えていることが好ましい。ＵＶ灯２０は点灯の積算時間によって劣化が進み、殺菌能力が定格に対してある割合よりも低くなった場合を寿命と呼ぶ。したがって、ＵＶ灯２０の点灯時間を積算し、ユーザに対してＵＶ灯２０の交換を促す機構がついていることで、ＵＶ灯２０の劣化による汚泥処理能力の低下を防ぐことができる。
【００１８】
本実施例によれば、特別にポンプや撹拌機を使用することなく、超音波処理槽５０へ重力で流入する汚泥の勢いと超音波発振による直進流を組み合わせることで超音波処理槽５０内での流動性を確保し、超音波の音場を安定させ汚泥処理の効率を向上し、安定した汚泥処理を低消費電力で行い、同時に超音波振動子１４の長寿命化も達成することができる。
また本実施例によれば、汚泥に対して超音波処理とＵＶ処理を組み合わせることで、汚泥の処理効率を高めることができる。つまり、ＵＶ灯２０を活用して超音波振動子１４の運転時間や出力をできるだけ低いレベルで運転し、低消費電力と超音波振動子１４の長寿命化を達成することができる。
【００１９】
図１０は同処理槽内の撹拌の状態を示す説明図である。
同図に示すように、第１の槽５１の下層では流入する流れの勢いで撹拌が行われ、第１の槽５１の中・上層では超音波振動子１４から発生する直進流によって、第１の槽５１の中層に振動子から反射壁へ向かう流れが生じ、この直進流が反射することで、第１の槽５１内が撹拌され、反射壁から堰５３へと向かって汚泥を押し流す強い水面の流れが発生する。このように第１の槽５１内に撹拌装置などを取り付けることなく、良好な流動状態を実現できる。
超音波放射面の対面から汚泥を流入することで、流入した汚泥は超音波放射面に平行で１／４波長の整数倍の間隔でできる定在波によるキャビテーションの中を通過する。仮に側面から汚泥を流入させると、汚泥はある一面のキャビテーションしか通過できず、超音波処理の効率は低下するが、本実施例では、キャビテーションの中を通過するため均一で効率の良い超音波処理ができる。
【００２０】
次に、ＵＶ灯を使用した場合の影響について以下に説明する。
図１１は同処理槽内でのＵＶ灯を使用した場合の影響を示すグラフ、図１２は溶存有機炭素（ＤＯＣ）と超音波照射出力との関係、及びＵＶ照射の影響を示すグラフである。
図１１では流量２Ｌ／ｍｉｎにおいて、無処理の場合、ＵＶ処理のみを行った場合、超音波処理のみを行った場合、超音波処理を行った後にＵＶ処理を行った場合についてのそれぞれのＤＯＣ（溶存有機炭素）を示している。同図に示すように、ＵＶ灯のみの処理の場合には無処理の場合と比べてＤＯＣに大きな変化は見られないが、超音波処理を施したものでは、ＵＶ処理を行う場合と行わない場合でＤＯＣに大きな変化が見られる。このことから、ＵＶ処理を超音波と併用することで、より相乗効果が高まることが分かる。
【００２１】
図１２は、超音波の照射出力を変化させた場合で、ＵＶ灯をＯＮした場合とＵＶ灯をＯＦＦした場合のＤＯＣの分析結果を示している。同図より超音波照射出力を大きくするほど効果は高くなるが、超音波出力が２８０Ｗを越えると、その効果の増加度合いが大きくなっていることが分かる。また超音波出力が大きいほど、すなわち超音波による分散・破砕作用を大きくするほどＵＶ灯の効果も大きくなっていることが分かる。
以上のことからも超音波照射の後に、ＵＶ灯を作用させることが重要であることが分かる。
このように超音波とＵＶ灯を併用することで、超音波振動子の運転時間を減少し、振動子の寿命を長くすることができる。
【００２２】
なお、本実施例では、超音波振動子を備えた超音波処理槽５０を２つの場合で説明したが、３つ以上の超音波処理槽５０を、高低差を持たせて配置し、汚泥を上方に位置する処理槽から順に下方に位置する処理槽に流出するように構成してもよい。
また、濁度計や酸素濃度計を用いることで、汚泥の状態を検出して超音波照射時間を制御してもよい。
また、本実施例における汚泥処理装置は、その他の汚泥処理に利用できる他、水の浄化や土壌の浄化としても利用することができる。
【００２３】
【発明の効果】
以上のように、本発明によれば、超音波照射の適正化を図り、処理効率がよく超音波振動子の長寿命化を図ることができる。特に、生物処理槽への負荷を考慮した運転を実現することで省エネルギーと超音波振動子の長寿命化を実現することができる。
また、本発明は、紫外線照射を併用し、紫外線照射を効率よく照射することで、更に低消費電力でコンパクトな装置を実現することができる。
【図面の簡単な説明】
【図１】本発明による一実施例の汚泥処理装置を示すブロック構成図
【図２】本発明による一実施例の汚泥処理装置を示すブロック構成図
【図３】本発明の一実施例による超音波処理装置の一部の構成を示す概略図
【図４】本発明の一実施例による超音波処理装置の制御方法を示すフローチャート
【図５】本発明の一実施例による超音波処理装置の制御パターンを示すタイムチャート
【図６】本発明の一実施例による超音波処理装置の操作方法を示すフローチャート
【図７】本発明の一実施例による超音波処理装置の全体構成を示す概略図
【図８】本発明の一実施例による超音波処理装置の処理槽の構成を示す側面図
【図９】同処理槽の上面図
【図１０】同処理槽内の撹拌の状態を示す説明図
【図１１】同処理槽内でのＵＶ灯を使用した場合の影響を示すグラフ
【図１２】溶存有機炭素（ＤＯＣ）と超音波照射出力との関係、及びＵＶ照射の影響を示すグラフ
【符号の説明】
１調整槽
２生物処理槽
２Ａ第一生物処理槽
３沈殿槽
４汚泥貯留槽
４Ａ第二生物処理槽
５超音波処理装置
６汚泥取入口
７汚泥返送口
１４超音波振動子
２０ＵＶ灯（紫外線照射手段）
５０超音波処理槽
５１第１の槽
５２第２の槽
５３堰
５４流入口
５５流出口[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a sludge treatment apparatus capable of significantly reducing organic matter in sludge generated by wastewater treatment.
[0002]
[Prior art]
Conventional sludge reduction technologies include biological / chemical sludge treatment and physical sludge treatment. The biological / chemical sludge treatment involves the use of chemicals, etc., which are performed in a short time (about 8 hours). It is suitable for small-volume sludge treatment, and the physical sludge treatment is a treatment that takes a long time (about 24 hours) using ultrasonic waves or the like, and is suitable for small-capacity sludge treatment (Patent Document 1, Patent Reference 2). In the treatment technique of Patent Document 2, for example, organic wastewater is treated in an aerobic biological treatment tank, and solid-liquid separation is performed in a sedimentation tank to obtain treated water and sludge. This sludge is circulated to the aerobic biological treatment tank as return sludge, and a part is introduced into the storage tank as surplus sludge. In the storage tank, the sludge is solubilized using ultrasonic waves oscillated from an ultrasonic oscillator, returned to the aerobic biological treatment tank as solubilized sludge, and biodegraded to reduce sludge volume. Is disclosed.
[0003]
[Patent Document 1]
JP-A-5-345192
[Patent Document 2]
JP-A-11-128975
[0004]
[Problems to be solved by the invention]
However, the above-mentioned conventional ultrasonic oscillator does not propose an operation in consideration of the load on the biological treatment tank, but it is proposed to extend the life of the ultrasonic oscillator, to achieve a compact device with low power consumption. Not.
[0005]
Accordingly, it is an object of the present invention to provide an apparatus that can optimize ultrasonic irradiation and that can improve the processing efficiency and extend the life of an ultrasonic transducer.
In particular, an object of the present invention is to realize an operation considering a load on a biological treatment tank, thereby realizing energy saving and extending the life of an ultrasonic vibrator.
Another object of the present invention is to realize a compact device with low power consumption.
[0006]
[Means for Solving the Problems]
The sludge treatment apparatus of the present invention according to claim 1, wherein in the biological treatment method for wastewater, a part of the sludge is introduced into an ultrasonic treatment apparatus, and the sludge ultrasonically treated by the ultrasonic treatment apparatus is subjected to a biological treatment method. A sludge treatment device to be transferred to a biological treatment tank, wherein the ultrasonic treatment device determines an ultrasonic irradiation time per unit time and periodically oscillates ultrasonic waves based on the determined irradiation time. Features.
According to a second aspect of the present invention, in the sludge treatment apparatus according to the first aspect, rated ultrasonic irradiation is performed based on a flow rate of sludge introduced into the ultrasonic treatment apparatus, a rated output of the ultrasonic vibrator, and an ultrasonic irradiation level. The amount is calculated, and the ultrasonic irradiation time is determined so as to attain the specified ultrasonic irradiation amount.
According to a third aspect of the present invention, in the sludge treatment apparatus according to the first aspect, a day is divided into a plurality of time zones, and the ultrasonic irradiation time varies depending on each time zone. .
The ultrasonic treatment apparatus of the present invention according to claim 4 is an ultrasonic treatment apparatus that introduces a part of sludge in a biological treatment method for wastewater and transfers the ultrasonically treated sludge to a biological treatment tank using the biological treatment method. There is provided a plurality of ultrasonic treatment tanks each equipped with an ultrasonic vibrator, each of the ultrasonic treatment tanks, arranged with a height difference, sequentially from the ultrasonic treatment tank located sludge above. It is characterized by flowing out into the ultrasonic treatment tank located below.
The ultrasonic treatment apparatus according to the fifth aspect of the present invention is an ultrasonic treatment apparatus for introducing a part of sludge and transferring the ultrasonically treated sludge to a biological treatment tank using the biological treatment method in the biological treatment method for wastewater. The ultrasonic treatment tank is provided with an ultrasonic oscillator and ultraviolet irradiation means, and the ultraviolet irradiation means is arranged on the downstream side of the sludge with respect to the ultrasonic oscillator.
The ultrasonic treatment tank of the present invention according to claim 6 is an ultrasonic treatment tank for introducing a part of sludge and transferring the ultrasonically treated sludge to a biological treatment tank using the biological treatment method in the biological treatment method for wastewater. A first tank and a second tank are separated by a weir, the first tank is provided with an inlet for sludge and an ultrasonic vibrator, and the second tank is provided with an outlet for sludge, The ultrasonic transducer is attached below the weir, with its radiation surface oriented parallel to the vertical direction, and the inflow port is provided on a reflecting wall facing the surface on which the ultrasonic transducer is attached. Features.
According to a seventh aspect of the present invention, in the ultrasonic treatment tank according to the sixth aspect, the ultraviolet irradiation means is arranged at a position where the sludge exceeding the weir is irradiated.
The present invention according to claim 8 is the ultrasonic treatment tank according to claim 6, wherein the ultraviolet irradiation means is constituted by a straight tube type or a U-tube type ultraviolet lamp, and the longitudinal direction of the ultraviolet lamp is set to the lengthwise direction. It is characterized by the direction of the weir.
According to a ninth aspect of the present invention, in the ultrasonic treatment tank according to the sixth aspect, the weir is provided over the entire inner wall of the first tank or the second tank.
According to a tenth aspect of the present invention, in the ultrasonic treatment tank according to the sixth aspect, the inflow port is provided at a position one third or less from a lower part in a height direction of the ultrasonic vibrator. And
The present invention according to claim 11 is the ultrasonic treatment tank according to claim 6, wherein the inflow port is provided at a position that is 1/3 or less of a height from the bottom of the first tank to the weir. It is characterized by the following.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The sludge treatment apparatus according to the first embodiment of the present invention determines an ultrasonic irradiation time per unit time and periodically oscillates ultrasonic waves based on the determined irradiation time. According to the present embodiment, while irradiating ultrasonic waves according to the biological activity state in the sludge, it is possible to extend the life of the ultrasonic vibrator as compared with continuous irradiation, By avoiding the period and performing periodic operation, it is possible to prevent sludge from adhering to the radiation surface of the ultrasonic transducer and to prevent sludge from settling on the bottom of the treatment tank, and to avoid the cause of failure of the ultrasonic transducer. Can be.
The second embodiment of the present invention relates to a sludge treatment apparatus according to the first embodiment, wherein the sludge flow rate to be introduced into the ultrasonic treatment apparatus, the rated output of the ultrasonic vibrator, and the ultrasonic irradiation level are used. The ultrasonic wave irradiation amount is calculated, and the ultrasonic wave irradiation time is determined so that the ultrasonic wave irradiation amount is instructed. According to the present embodiment, it is possible to determine an appropriate irradiation amount according to the sludge flow rate.
According to a third embodiment of the present invention, in the sludge treatment apparatus according to the first embodiment, one day is divided into a plurality of time zones, and the ultrasonic irradiation time is varied depending on each time zone. . For example, when the incoming wastewater is domestic wastewater, the amount of wastewater varies according to the household life cycle, so the load on the biological treatment tank also changes according to the household life cycle. For example, in the early morning to late night when the load on the biological treatment tank increases, the ultrasonic vibrator is operated in the “strong operation mode”, and in the late night to early morning when the load on the biological treatment tank decreases, the ultrasonic vibrator operates in the “weak operation”. By operating in the “mode”, it is possible to save energy and extend the life of the ultrasonic vibrator.
The ultrasonic processing apparatus according to the fourth embodiment of the present invention includes a plurality of ultrasonic processing tanks each including an ultrasonic vibrator, and each of the ultrasonic processing tanks is arranged with a height difference, and the sludge Flow out of the upper ultrasonic processing tank to the lower ultrasonic processing tank. According to the present embodiment, since the inside of the apparatus flows by gravity without using a power source such as a pump, a compact apparatus with low power consumption can be realized, and is also suitable for a case where the apparatus is installed in an existing wastewater treatment facility.
The ultrasonic processing apparatus according to the fifth embodiment of the present invention includes an ultrasonic processing tank provided with an ultrasonic oscillator and an ultraviolet irradiation unit, and the ultraviolet irradiation unit is disposed on the downstream side of the sludge with respect to the ultrasonic oscillator. Things. According to the present embodiment, since the sludge treatment efficiency can be increased by combining the ultrasonic treatment and the ultraviolet irradiation treatment for the sludge, the operation time and output of the ultrasonic vibrator using the ultraviolet irradiation can be improved. Can be operated at the lowest possible level to achieve low power consumption and long life of the ultrasonic transducer.
The ultrasonic treatment tank according to the sixth embodiment of the present invention divides a first tank and a second tank by a weir, and comprises a sludge inlet and an ultrasonic vibrator in the first tank. The tank has a sludge outlet, and the ultrasonic vibrator is mounted below the weir so that its radiation surface is oriented parallel to the vertical direction, and the ultrasonic vibrator is mounted on a reflective wall facing the surface on which the ultrasonic vibrator is mounted. An inlet is provided. According to the present embodiment, by flowing sludge from the opposite surface of the ultrasonic radiation surface, the inflow sludge is parallel to the ultrasonic radiation surface, and the cavitation due to the standing wave generated at an interval of an integral multiple of 1/4 wavelength. Since it passes through the inside, uniform and efficient ultrasonic treatment can be performed.
According to a seventh embodiment of the present invention, in the ultrasonic treatment tank according to the sixth embodiment, the ultraviolet irradiation means is arranged at a position for irradiating sludge over the weir. According to the present embodiment, the sludge that has been subjected to the ultrasonic treatment can be efficiently irradiated with ultraviolet rays.
According to an eighth embodiment of the present invention, in the ultrasonic treatment tank according to the sixth embodiment, the ultraviolet irradiation means is constituted by a straight tube type or a U-tube type ultraviolet lamp, and a longitudinal direction of the ultraviolet lamp is used. Is the direction of the weir. According to the present embodiment, it is possible to uniformly irradiate the sludge over the weir with ultraviolet rays.
In a ninth embodiment of the present invention, in the ultrasonic treatment tank according to the sixth embodiment, a weir is provided over the entire inner wall of the first tank or the second tank. According to the present embodiment, convection of sludge by the weir can be prevented, smooth flow can be realized, and ultraviolet irradiation can be performed efficiently.
According to a tenth embodiment of the present invention, in the ultrasonic treatment tank according to the sixth embodiment, the inflow port is provided at a position of 1/3 or less from the lower part in the height direction of the ultrasonic vibrator. is there.
According to an eleventh embodiment of the present invention, in the ultrasonic treatment tank according to the sixth embodiment, the inflow port is provided at a position which is not more than 1/3 of the height from the bottom of the first tank to the weir. It is something.
According to these embodiments, the lower layer of the tank is agitated by the flow of the sludge flowing therein, and the middle and upper layers of the tank are subjected to a straight flow generated by the ultrasonic vibrator and acoustic radiation generated in the traveling direction of the ultrasonic wave. Due to the pressure, a flow from the vibrator to the reflecting wall is generated in the middle layer of the tank, and the flow toward the reflecting wall is reflected, so that the inside of the tank is agitated, and the strong water surface that flushes the sludge from the reflecting wall to the weir is generated. Flow occurs. In addition, a good fluidized state can be realized without installing a stirrer or the like in the tank.
[0008]
【Example】
Hereinafter, a sludge treatment apparatus according to an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are block diagrams showing a sludge treatment apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the wastewater treatment facility includes an adjustment tank 1 for storing wastewater, a biological treatment tank 2 for treating organic matter with microorganisms, and a sedimentation tank for separating wastewater treated in the biological treatment tank 2 into sludge and water by gravity. 3, a sludge storage tank 4 for introducing the sludge separated in the sedimentation tank 3, and an ultrasonic treatment device 5 for performing ultrasonic treatment.
Wastewater flows into the wastewater treatment facility through a sewer pipe. The inflowed wastewater temporarily stays in the adjusting tank 1, a certain amount flows into the biological treatment tank 2, and is purified by microorganisms propagated in the biological treatment tank 2 (hereinafter referred to as activated sludge as an example). Activated sludge flows into the sedimentation tank 3 according to the amount of inflow into the biological treatment tank 2, and is separated into excess sludge and treated water by gravity. A part of the separated sludge is returned to the biological treatment tank 2 as return sludge, and the other is subjected to ultrasonic treatment in the ultrasonic treatment device 5 and then flows into the biological treatment tank 2 again, and the rest is excess sludge. And transferred to the sludge storage tank.
[0009]
In FIG. 2, the biological treatment tank 2 in FIG. 1 is configured as a first biological treatment tank 2A, and similarly, the sludge storage tank 4 in FIG. 1 is configured as a second biological treatment tank 4A.
Wastewater flows into the wastewater treatment facility through a sewer pipe. The inflowed wastewater temporarily stays in the adjustment tank 1, a certain amount flows into the first biological treatment tank 2A, and is purified by the activated sludge propagated in the first biological treatment tank 2A. Activated sludge flows into the sedimentation tank 3 according to the amount of inflow into the first biological treatment tank 2A, and is separated into excess sludge and treated water by gravity. A part of the excess sludge is returned to the first biological treatment tank 2A as returned sludge, and the rest is transferred to the second biological treatment tank 4A, subjected to ultrasonic treatment in the ultrasonic treatment device 5, and then returned to the second biological treatment tank 4A. Flow into biological treatment tank. In the second biological treatment tank, for example, a membrane separation device is installed in order to remove moisture in the sludge, and the permeated water flows into the adjustment tank. In addition, the membrane permeated water may flow into the aeration tank, or may be discharged as it is. Further, the membrane separation device may be installed outside the second biological treatment tank.
[0010]
Next, a control method of the ultrasonic processing apparatus will be described with reference to FIGS.
FIG. 3 is a schematic diagram showing a configuration of a part of the ultrasonic processing apparatus according to one embodiment of the present invention.
Part of the surplus sludge is introduced into the ultrasonic treatment tank 50 through the flow control valve 11. The amount of the introduced sludge is measured by the flow meter 12. The control unit 13 receives the flow rate measured by the flow meter 12 and controls the flow control valve 11 and the ultrasonic transducer 14. Note that this is an example, and a metering pump may be used.
[0011]
FIG. 4 is a flowchart illustrating a control method of the ultrasonic processing apparatus according to an embodiment of the present invention.
First, a surplus sludge generation amount (A [L / day]) is input (S1). Further, an ultrasonic irradiation level (C [%] rated ratio) is input (S2).
The processing flow rate (Q [L / min] = K × A ÷ (24 × 60)) is calculated by the control unit 13 based on the input surplus sludge generation amount (S3). Here, K is a processing multiple and is 1 to 10, preferably 2 to 5 times.
The flow rate is measured by the flow meter 12 (S4), and the control unit 13 adjusts the flow control valve 11 so that the processing flow rate calculated in S3 is obtained (S5).
The control unit 13 determines the ultrasonic irradiation amount (Pc = 0.01 · C) based on the flow rate (Q), the rated output (P [W]) of the ultrasonic vibrator 14, and the ultrasonic irradiation level (C [%]). • (PV) / (60Q) [Wh]) is calculated (S6). V [L] is the volume of the ultrasonic irradiation tank, V / Q ([min]) is the residence time of the sludge in the ultrasonic irradiation tank, and (PV) / (60Q) ([Wh]). Is the rated ultrasonic irradiation dose.
In the case where the operation mode of the ultrasonic vibrator 14 includes a strong operation mode and a weak operation mode, the ultrasonic treatment time in the weak operation mode is set to 10% to 50% of the strong operation, and the biological treatment tank 2 is set. It is preferable to decompose the sludge with the remaining power to extend the life of the ultrasonic vibrator.
The control unit 13 determines the operation time of the ultrasonic vibrator 14 so as to achieve the specified ultrasonic irradiation amount (S7).
[0012]
FIG. 5 is a time chart showing a control pattern of the ultrasonic processing apparatus according to one embodiment of the present invention.
Since the amount of wastewater flowing into the biological treatment tank 2 increases or decreases according to the household life cycle, the load on the biological treatment tank 2 also changes according to the household life cycle. FIG. 4 shows a time change of the amount of wastewater flowing into the biological treatment tank 2. As shown in the figure, it can be roughly classified into early morning to late night and late night to early morning.
Therefore, in the present embodiment, the ultrasonic vibrator 14 is operated in the “strong operation mode” in the early morning to late night when the load on the biological treatment tank 2 becomes large, and in the late night to early morning when the load on the biological treatment tank 2 becomes small. By operating the ultrasonic vibrator 14 in the “weak operation mode”, energy saving and a long life of the ultrasonic vibrator 14 can be realized.
For example, the ultrasonic irradiation time (T [min]) determined from the rated output (P [W]) of the ultrasonic vibrator and the ultrasonic irradiation amount (Pc [Wh]) is in the strong operation mode (early morning to midnight). Case), T = (Pc / P) · 60 [min], and 0.1 T-0.5 T in the weak operation mode (from late night to early morning).
Here, it is preferable that the operation of the ultrasonic vibrator 14 be turned on and off in a cycle of one hour or less. For example, once every several hours, the flow rate and other turbidity are measured, and when the operation time of the ultrasonic vibrator 14 is turned on and off, sludge adheres to the radiation surface of the ultrasonic vibrator 14 and This causes a failure of the vibrator 14. Moreover, sludge may precipitate on the bottom surface of the ultrasonic treatment tank 50.
[0013]
FIG. 6 is a flowchart illustrating a method of operating the ultrasonic processing apparatus according to one embodiment of the present invention. This operation is mainly performed by the user, but the data of the amount of generated sludge can be received from the facility and processed automatically.
First, the generation amount (L / day) of sludge is confirmed (received) from the operation management data of the wastewater treatment facility (S11).
Then, the amount of generated sludge and the ultrasonic irradiation level are instructed (output) (50% initially) to the ultrasonic processing apparatus 5 (S12).
After the instruction (output) in S12, the amount of generated sludge is confirmed after a predetermined period (for example, 2 to 4 weeks) from the start of operation (S13). As a result of the confirmation, if the amount of generated sludge has decreased, the ultrasonic irradiation level is maintained (S14), and if the amount of generated sludge has not changed or if the amount of generated sludge has increased, the ultrasonic wave has been applied. The irradiation level is increased (S15). Thus, the irradiation amount is controlled according to the amount of sludge generated and the load on the biological treatment tank 2. For example, the ultrasonic vibrator 14 is operated in the "strong operation mode" in the early morning to late night when the load on the biological treatment tank 2 increases, and the ultrasonic vibrator 14 is operated in the late night to early morning when the load on the biological treatment tank 2 decreases. By operating in the “weak operation mode”, energy saving and long life of the ultrasonic vibrator can be realized.
[0014]
Next, the overall configuration of the ultrasonic processing apparatus will be described with reference to FIG.
FIG. 7 is a schematic diagram showing the entire configuration of the ultrasonic processing apparatus according to one embodiment of the present invention.
In the ultrasonic treatment apparatus 5 of this embodiment, a sludge inlet 6 is disposed below the apparatus main body so that the flow is stable even at a small flow rate, and the sludge is temporarily moved from the sludge intake 6 to an upper part of the apparatus main body. The sludge is processed as it moves downward from the upper part, and is discharged from the sludge return port 7 provided in the lower part of the apparatus main body. A flow control valve 11, a flow meter 12, and a turbidity meter 15 are arranged on a pipe for moving the sludge from the sludge inlet 6 to an upper portion of the apparatus main body. On the other hand, two ultrasonic treatment tanks 50A and 50B are arranged in a pipe for moving sludge from the upper part of the apparatus main body to the sludge return port 7. Then, the sludge is treated in the ultrasonic treatment tank 50A disposed in the upper part, and then treated in the ultrasonic treatment tank 50B disposed below the ultrasonic treatment tank 50A, and is guided to the sludge return port 7.
The ultrasonic processing device 5 is provided with ultrasonic transmitters 16A and 16B in accordance with the ultrasonic processing tank 50, and the ultrasonic transmitter 16A transmits the ultrasonic transducer 14A installed in the ultrasonic processing tank 50A, The ultrasonic transmitter 16B transmits the ultrasonic transducer 14B installed in the ultrasonic processing tank 50B. A degassing pipe 18 is used as a connecting pipe between the ultrasonic processing tank 50A and the ultrasonic processing tank 50B. The on-off valve 17 is used when discharging sludge in the apparatus main body.
[0015]
In the ultrasonic processing apparatus 5 of the present embodiment, the sludge taken into the uppermost ultrasonic processing tank 50A flows through the apparatus by gravity without using a power source such as a pump, and can be returned to the wastewater treatment facility. it can. When the number of the ultrasonic treatment tanks 50 is two or more, it is preferable to arrange the ultrasonic treatment tanks 50 with a vertical difference.
The ultrasonic treatment apparatus 5 of the present embodiment can realize a compact apparatus with low power consumption by arranging the ultrasonic treatment tank 50 and the piping configuration as described above, and can be installed in an existing wastewater treatment facility. Are also suitable.
[0016]
Next, a processing tank of the ultrasonic processing apparatus will be described with reference to FIGS.
FIG. 8 is a side view showing a configuration of a processing tank of the ultrasonic processing apparatus according to one embodiment of the present invention, and FIG. 9 is a top view of the processing tank.
The ultrasonic treatment tank 50 includes a first tank 51 and a second tank 52 therein, and the first tank 51 and the second tank 52 are partitioned by a weir 53. The inside sludge is configured to be guided to the second tank 52 over the weir 53. The width of the weir 53 is provided between the inner walls of the first tank 51 or the second tank 52, and is preferably provided over the entire width of the inner wall.
The ultrasonic vibrator 14 is mounted on the surface of the first tank 51 on the side of the weir 53 so that the radiation surface faces in parallel with the vertical direction, and the surface facing the surface on which the ultrasonic vibrator 14 is mounted. (Reflective wall) is provided with an inflow port 54 for sludge. On the other hand, an outlet 55 for discharging sludge is provided below the second tank 52. Further, a drain port 56 for discharging sludge settled on the bottom surface of the first tank 51 is provided on the bottom surface of the first tank 51. The sludge is overflowed from above the ultrasonic vibrator 14 while maintaining a constant water level by the weir 53 by the weir 53 above the mounting surface of the ultrasonic vibrator 14.
Here, the inflow port 54 is provided at a position that is 1/3 or less from the lower part in the height direction of the ultrasonic transducer 14. In addition, the first tank 51 is provided at a position that is １／ or less of the height from the bottom surface to the weir 53. It is preferable that the inflow port 54 is formed with a projection having a length equal to or less than the wavelength λ in the first tank 51. The wavelength λ [m] of the ultrasonic wave when the oscillation frequency of the ultrasonic wave is f [Hz] and the sound velocity in water is a [m / s] is λ = a / f [m].
In the second tank 52 located above the weir 53, the UV lamp 20 as ultraviolet irradiation means is attached. The UV lamp 20 is of a straight tube type or a U-tube type, and is mounted so that the central axis thereof is parallel to the weir 53.
By providing the UV lamp 20 in the second tank 52, the sludge is irradiated by the UV lamp 20 after the ultrasonic irradiation is performed. Further, the UV irradiation of the sludge is performed when flowing down the weir 53 and when staying at the discharge port.
[0017]
In this embodiment, the sludge is first irradiated with ultrasonic waves by the above configuration, and flocs of the sludge are dispersed and crushed by the ultrasonic waves, so that the surface area of the sludge particles that is exposed to light increases. Further, the sludge is thinly stretched by the weir 53 and flows down while being thinly stretched over the surface of the weir 53 even after passing over the weir 53. Further, the flow that has flowed down flows toward the outlet in a state of being stretched thinly. Since the UV lamp 20 is attached so that the ultraviolet light is applied to the sludge that has been stretched thinly, even the sludge having a large turbidity can uniformly irradiate the entire amount of the ultraviolet light. As described above, the sludge absorbs UV uniformly, so that the sludge cells are sufficiently destroyed.
In addition, it is preferable to provide a display mechanism for accumulating the lighting time of the UV lamp 20 and prompting the user to replace the UV lamp 20 when the rated life time is reached. The life of the UV lamp 20 is referred to as the life when the deterioration progresses due to the integrated lighting time and the sterilization ability becomes lower than a certain ratio with respect to the rating. Therefore, since a mechanism for accumulating the lighting time of the UV lamp 20 and urging the user to replace the UV lamp 20 is provided, it is possible to prevent a decrease in the sludge treatment capacity due to deterioration of the UV lamp 20.
[0018]
According to the present embodiment, without using a pump or a stirrer, a combination of the force of the sludge flowing into the ultrasonic treatment tank 50 by gravity and the straight flow by the ultrasonic oscillation is used in the ultrasonic treatment tank 50. , The sound field of the ultrasonic wave is stabilized, the efficiency of the sludge treatment is improved, the stable sludge treatment is performed with low power consumption, and at the same time, the life of the ultrasonic vibrator 14 can be extended. .
Further, according to the present embodiment, the sludge treatment efficiency can be increased by combining the ultrasonic treatment and the UV treatment on the sludge. In other words, the operation time and output of the ultrasonic vibrator 14 can be operated at the lowest possible level by utilizing the UV lamp 20, and low power consumption and a long life of the ultrasonic vibrator 14 can be achieved.
[0019]
FIG. 10 is an explanatory view showing a state of stirring in the processing tank.
As shown in the figure, in the lower layer of the first tank 51, stirring is performed by the force of the flowing flow, and in the middle and upper layers of the first tank 51, the first flow is generated by the straight flow generated from the ultrasonic transducer 14. A flow from the vibrator toward the reflecting wall is generated in the middle layer of the first tank 51, and the straight flow is reflected, whereby the inside of the first tank 51 is agitated, and a strong water surface for flushing the sludge from the reflecting wall to the weir 53. Flow occurs. Thus, a good fluidized state can be realized without attaching a stirrer or the like in the first tank 51.
When the sludge flows in from the opposite surface of the ultrasonic wave emitting surface, the sludge that has flowed in passes through the cavitation due to standing waves that are parallel to the ultrasonic wave emitting surface and formed at intervals of an integral multiple of 1/4 wavelength. If sludge flows in from the side, the sludge can only pass through a certain surface of cavitation, and the efficiency of ultrasonic treatment is reduced.However, in this embodiment, since the sludge passes through cavitation, uniform and efficient ultrasonic treatment is performed. Can be.
[0020]
Next, the effect of using a UV lamp will be described below.
FIG. 11 is a graph showing the effect of using a UV lamp in the treatment tank, and FIG. 12 is a graph showing the relationship between dissolved organic carbon (DOC) and ultrasonic irradiation output, and the effect of UV irradiation.
In FIG. 11, at the flow rate of 2 L / min, the respective DOCs for the case of no treatment, the case of performing only the UV treatment, the case of performing only the ultrasonic treatment, and the case of performing the UV treatment after performing the ultrasonic treatment are shown. (Dissolved organic carbon). As shown in the figure, there is no significant change in the DOC in the case of the processing using only the UV lamp as compared with the case in which no processing is performed. In some cases, a large change in DOC is seen. From this, it is understood that the synergistic effect is further enhanced by using the UV treatment together with the ultrasonic wave.
[0021]
FIG. 12 shows the DOC analysis results when the irradiation output of the ultrasonic wave is changed, and when the UV lamp is turned on and when the UV lamp is turned off. As can be seen from the figure, the effect increases as the ultrasonic irradiation output increases, but when the ultrasonic output exceeds 280 W, the degree of increase in the effect increases. Also, it can be seen that the effect of the UV lamp increases as the ultrasonic output increases, that is, as the dispersion / crushing action by the ultrasonic waves increases.
From the above, it is understood that it is important to apply a UV lamp after ultrasonic irradiation.
As described above, by using the ultrasonic wave and the UV lamp together, the operation time of the ultrasonic vibrator can be reduced, and the life of the vibrator can be prolonged.
[0022]
In this embodiment, two ultrasonic treatment tanks 50 each including an ultrasonic vibrator have been described. However, three or more ultrasonic treatment tanks 50 are arranged with a difference in height to remove sludge. It may be configured to flow out from the processing tank located above to the processing tank located below in order.
Further, by using a turbidity meter or an oxygen concentration meter, the state of sludge may be detected to control the ultrasonic irradiation time.
Further, the sludge treatment apparatus in this embodiment can be used for other sludge treatment, and can also be used for water purification and soil purification.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to optimize ultrasonic irradiation, achieve good processing efficiency, and extend the life of the ultrasonic transducer. In particular, by realizing the operation in consideration of the load on the biological treatment tank, it is possible to save energy and extend the life of the ultrasonic vibrator.
Further, according to the present invention, by using ultraviolet irradiation together with efficient irradiation of ultraviolet irradiation, a compact device with lower power consumption can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a sludge treatment apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a sludge treatment apparatus according to an embodiment of the present invention.
FIG. 3 is a schematic diagram showing a partial configuration of an ultrasonic processing apparatus according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating a control method of the ultrasonic processing apparatus according to an embodiment of the present invention.
FIG. 5 is a time chart showing a control pattern of the ultrasonic processing apparatus according to one embodiment of the present invention.
FIG. 6 is a flowchart illustrating a method of operating the ultrasonic processing apparatus according to an embodiment of the present invention.
FIG. 7 is a schematic diagram showing an overall configuration of an ultrasonic processing apparatus according to an embodiment of the present invention.
FIG. 8 is a side view showing a configuration of a processing tank of the ultrasonic processing apparatus according to one embodiment of the present invention.
FIG. 9 is a top view of the processing tank.
FIG. 10 is an explanatory view showing a stirring state in the processing tank.
FIG. 11 is a graph showing the effect of using a UV lamp in the treatment tank.
FIG. 12 is a graph showing the relationship between dissolved organic carbon (DOC) and ultrasonic irradiation output, and the effect of UV irradiation.
[Explanation of symbols]
1 adjustment tank
2 biological treatment tank
2A First biological treatment tank
3 Sedimentation tank
4 Sludge storage tank
4A Second biological treatment tank
5 Ultrasonic processing equipment
6 Sludge intake
7 Sludge return port
14 Ultrasonic transducer
20 UV lamp (ultraviolet irradiation means)
50 Ultrasonic treatment tank
51 First tank
52 Second tank
53 weir
54 Inlet
55 outlet

Claims

In the biological treatment method of wastewater, a part of sludge is introduced into an ultrasonic treatment device, and the sludge treated by ultrasonic treatment in the ultrasonic treatment device is transferred to a biological treatment tank by a biological treatment method. ,
The sludge treatment device according to claim 1, wherein the ultrasonic treatment device determines an ultrasonic irradiation time per unit time and periodically oscillates an ultrasonic wave based on the determined irradiation time.

Calculate the rated ultrasonic irradiation amount from the flow rate of sludge to be introduced into the ultrasonic treatment device, the rated output of the ultrasonic vibrator, and the ultrasonic irradiation level, and perform the ultrasonic irradiation so that the ultrasonic irradiation amount is instructed. The sludge treatment apparatus according to claim 1, wherein the time is determined.

The sludge treatment apparatus according to claim 1, wherein a day is divided into a plurality of time zones, and the ultrasonic irradiation time is varied according to each time zone.

An ultrasonic treatment device that introduces a part of sludge in the biological treatment method for wastewater and transfers the ultrasonically treated sludge to a biological treatment tank using the biological treatment method, and is provided with ultrasonic vibrators. A plurality of tanks are provided, each of the ultrasonic treatment tanks is arranged with a height difference, and the sludge flows out of the ultrasonic treatment tank located in the upper part to the ultrasonic treatment tank located in the lower part in order. Characteristic ultrasonic processing device.

An ultrasonic treatment device that introduces a part of the sludge in the biological treatment method of wastewater and transfers the ultrasonically treated sludge to the biological treatment tank using the biological treatment method. An ultrasonic processing apparatus, comprising: an irradiation unit, wherein the ultraviolet irradiation unit is disposed downstream of the sludge with respect to the ultrasonic vibrator.

In the biological treatment method of wastewater, an ultrasonic treatment tank that introduces a part of sludge and transfers the ultrasonically treated sludge to a biological treatment tank by the biological treatment method,
A first tank and a second tank that are separated by a weir, the first tank is provided with a sludge inlet and an ultrasonic vibrator, the second tank is provided with a sludge outlet, and the ultrasonic vibration is provided. A transducer is attached below the weir so that its radiation surface faces parallel to the vertical direction, and the inlet is provided on a reflecting wall facing the surface on which the ultrasonic vibrator is attached. Ultrasonic treatment tank.

The ultrasonic treatment tank according to claim 6, wherein the ultraviolet irradiation means is arranged at a position where the sludge irradiating the weir exceeds the weir.

The ultrasonic treatment tank according to claim 6, wherein the ultraviolet irradiation means is constituted by a straight tube type or U-tube type ultraviolet lamp, and a longitudinal direction of the ultraviolet lamp is set to a direction of the weir.

The ultrasonic treatment tank according to claim 6, wherein the weir is provided over the entire width of the inner wall of the first tank or the second tank.

The ultrasonic treatment tank according to claim 6, wherein the inflow port is provided at a position one third or less from a lower part in a height direction of the ultrasonic vibrator.

The ultrasonic treatment tank according to claim 6, wherein the inflow port is provided at a position that is not more than 1/3 of a height from a bottom surface of the first tank to the weir.