JP3911742B2

JP3911742B2 - Organic wastewater anaerobic treatment equipment

Info

Publication number: JP3911742B2
Application number: JP32536296A
Authority: JP
Inventors: 元之依田
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 1996-12-05
Filing date: 1996-12-05
Publication date: 2007-05-09
Anticipated expiration: 2016-12-05
Also published as: JPH10165980A

Description

【０００１】
【発明の属する技術分野】
この発明は有機性排水中の有機物を、沈積層を構成する嫌気性微生物からなるグラニュールや、その前駆体（小粒径のグラニュール）である自己造粒汚泥（単に汚泥とも記す。）で最終的にメタンと二酸化炭素を主成分とする嫌気性ガスに分解して有機物を除去し、有機物の分解が済んだ処理水を、発生した嫌気性ガス、及び汚泥から分離して取出すＵＡＳＢ式（上向流スラッジブランケット式）嫌気性処理装置に関する。
【０００２】
【従来の技術】
図３に示すように、頂部にガス抜き管１１を有する有蓋の処理槽１０と、上端部が槽内の水面上に突出し、水面下で傾斜して下端が槽内の高さの中程に位置する傾斜分離板１２と、この傾斜分離板により槽内に隔離して設けられた汚泥沈殿室１３、及び反応室１４と、反応室の槽底部上に形成される嫌気性汚泥層１５と、該嫌気性汚泥層中に有機性排水を供給する給水管１６と、前記汚泥沈殿室の上部に、傾斜分離板に接して設けられた処理水の溢流トラフ１７と、前記反応室の内部で、汚泥沈殿室の下部に傾斜して設けられたガス分離板１８とを備えた有機性排水の嫌気性処理装置は従来から公知である。処理槽１０の平面形状は円筒形でも、角筒形でもよいが、円筒形の場合は傾斜分離板１２は直径が下向きに小さくなった円錐筒であり、ガス分離板１８は陣笠形である。尚、傾斜分離板の円錐板は上半部１２ａと、上部が上半部の下部よりも直径が少し大きい下半部１２ｂとからなり、上半部の下部と下半部の上部は内外に同心状に嵌合し、その間に陣笠状のガス分離板の周面に向う円錐形の通路１２´を形成している。このような構成により、汚泥沈殿室１３の下部開口部は、流路を残してガス分離板１８によって下方から覆われた状態となっている。
【０００３】
給水管１６から処理槽内に供給された原水（有機性排水）は、嫌気性汚泥層中を上昇する際に、含有する有機物を該汚泥層を構成する汚泥の嫌気性微生物により分解されて処理水となり、処理水は分解により生成した嫌気性ガスの上昇に随伴して一部の汚泥を伴って反応室１４内を上向流する。そして、一部の処理水はガス分離板１８の回りから、汚泥沈殿室１３内に下端の入口から入って室内を上昇する上昇流Ａになる。汚泥沈殿室の下端の入口はガス分離板１８で遮られ、汚泥を伴った処理水が直接、汚泥分離室に上向流しないので、ガスは分離され、汚泥沈殿室に流入した処理水の上昇流Ａに含まれた汚泥は室内で分離し、汚泥は汚泥沈殿室に下から流入する処理水に抗して沈殿室の下端の入口からガス分離板上に落下し、ガス分離板の回りから嫌気性汚泥層１５上に沈下する。従って、汚泥を分離した処理水は溢流トラフ１７に溢入し、排出管１９から取出される。又、発生した嫌気性ガスの一部はガス分離板１８の下に集まり、ガス分離板の回りや、処理槽が角筒状の場合は山形断面のガス分離板の両端から沈殿室の外の液面に浮上し、ガス抜き管１１から放出される。
【０００４】
汚泥沈殿室に流入しなかった汚泥を含んだ残りの処理水は嫌気性ガスに随伴して傾斜分離板１２の回りの反応室の上部に上昇し、嫌気性ガスは反応室の液面に浮上し、ガス抜き管１１から放出される。
嫌気性ガスに随伴して反応室の上部に上昇する処理水の上昇速度は、原水中のＣＯＤcr負荷量、つまり生成される嫌気性ガスの量によって定まり、ＣＯＤcr負荷量が高い程、嫌気性ガスの生成量は大になるので処理水の上昇速度は早まる。こうして、反応室内で嫌気性ガスを放出した処理水は、嫌気性ガスによる上昇流Ｂの反転流Ｃとして反応室内の傾斜分離板１２の外側に沿って傾斜分離板の下方の円錐形の通路１２´中を下降し、処理水に含まれる汚泥は嫌気性汚泥層１５上に沈下する。
【０００５】
【発明が解決しようとする課題】
上記従来装置はＣＯＤcr負荷量が１５ｋｇ／ＣＯＤ／ｍ³ ／日程度までの有機性排水であれば、充分に処理を行うことができるが、ＣＯＤ負荷量が２０ｋｇ／ＣＯＤ／ｍ³ ／日、或いはそれ以上に高い有機性排水の場合は、生成する嫌気ガスの量が多いので反応室内の上昇流Ｂと、その後の傾斜分離板の外側に沿って通路１２´中を下降する反転流Ｃは高速になり、ガス分離板１８上に激しく衝突し、一部が反射的な上向きの衝突流Ｄになって沈殿室１３の内部に浸入し、沈殿室での汚泥の沈殿を妨げたり、沈殿すべき汚泥が溢流トラフ１７に流入し、排出管１９から取出される処理水に汚泥が混ざることがある。つまり、反応室内の傾斜分離板１２に沿って下降する反転流Ｃが、嫌気性ガスによって反応室内を上昇する上昇流Ｂの反転流を利用したものであるため、ＣＯＤcr負荷量の上昇に伴う上昇流Ｂの流速の上昇が反転流Ｃの流速の上昇につながり、結果として沈殿室１３内に反射的に上昇して室内を攪拌する垂直上向きの衝突流Ｄが無視できない悪影響を及ぼし、前述したように沈殿室での汚泥の沈殿を妨げたり、汚泥が排出管１９に流出するのである。又、汚泥沈殿室内で分離した汚泥は該室に流入して上昇流Ａとなる処理水の流れに抗してガス分離板上に落下しなければならないので汚泥沈殿室に汚泥が滞流し、嫌気性汚泥層１５の汚泥量が不足することがある。
【０００６】
【課題を解決するための手段】
そこで本発明は、原水のＣＯＤcr負荷量が高くても、嫌気性ガスによる処理水の上昇流の影響を受けることなく処理水中に含まれている汚泥を確実に沈殿分離し、分離した汚泥を強制的に嫌気性汚泥層に返送することにより上記した従来装置の問題点を完全に解消したもので、有機性排水の嫌気性処理装置として、底部に嫌気性汚泥層と、該汚泥層中に有機性排水を上向流で供給する給水管とを有する反応部を備えた処理槽の内部の、上記反応部の上方に、上端部が槽内の水面上に突出した有底の円筒形の沈殿部を配置し、この沈殿部内の上部に処理水を処理槽外に取出すための溢流装置を設け、該沈殿部の回りには沈殿部沿いに間隔を保って仕切壁を配置し、沈殿部と仕切壁との間の上記間隔を反応部から上昇する処理水の一部が流入する上昇水路にし、この上昇水路と沈殿部の内部を連通する連通手段を設け、この連通手段には沈殿部の内部に処理水を接線方向に供給する接線方向の供給口を形成すると共に、前記上昇水路の下端の下方に、該上昇水路中に嫌気性ガスが進入するのを防ぐじゃま板を設け、且つ沈殿部の底と反応部との間には沈殿部の底に沈降した汚泥を反応部に返送する返送管を設けたことを特徴とする。
【０００７】
【実施例】
図１，２の各実施例において、２０は頂部にガス抜き管２０´を有する有蓋の処理槽、２２は処理槽の内部に形成された汚泥からなる嫌気性汚泥層、２３は上記嫌気性汚泥層中に原水（有機性排水）を供給して上向流させる給水管であり、嫌気性汚泥層を構成する汚泥は上向流する原水により処理槽の高さの中程まで流動状態に展開する。原水の給水管２３と、流動状態に展開する嫌気性汚泥層２２とにより処理槽内の下半部に反応部２１が構成される。
【０００８】
処理槽の内部の上記反応部２１の上方に、上端部が槽内の水面Ｗ上に突出した有底の円筒形の沈殿部２４を配置する。沈殿部２４の底２４´は、図示の実施例では夫々断面Ｖ字形の円錐形に閉じ、前記反応部２１の上に離れて位置する。この沈殿部内の上部には沈殿部内の処理水が溢入する溢流装置２５が設けてあり、溢流装置に溢入した処理水は排水管２６で槽外に取出される。尚、溢流装置２５は、図１の実施例では沈殿部２４の上部内周に沿って設けられたトラフであり、図２の実施例では沈殿部２４の上部中心に設けられた盃形容器である。
【０００９】
沈殿部２４の回りには、仕切壁２８を沈殿部沿いに間隔を保って配置し、沈殿部と仕切壁との間の上記間隔で、反応部２１から上昇する処理水が流入する上昇水路２９を形成する。そして、この上昇水路２９の処理水を沈殿部の内部に供給する連通手段３０を設け、連通手段には沈殿部の水中に処理水を接線方向に供給する接線方向の供給口３１を形成する。図１の実施例の連通手段３０は、上昇水路２９中に設けられ、該水路の水面から溢入する処理水を下降させる導水管３２と、導水管の下端に接続し、沈殿部の壁を接線方向に貫通した前記供給口３１とからなる。又、図２の実施例の連通手段３０は、沈殿部の壁に開設された孔に取付けられて沈殿部の水中に接線方向に突出する前記供給口３１である。
【００１０】
沈殿部２４の底と、反応部２１との間には沈殿部の底に沈降した汚泥を反応部に返送する返送管３３を設ける。返送管３３にはポンプＰを接続し、ポンプを連続的、又は間欠的に運転し、沈殿部の底から汚泥を反応部に供給する。
【００１１】
沈殿部の外面と、沈殿部を囲む仕切壁の内面との間の間隔に形成された上昇水路２９の下端の下方に、反応部２１から浮上した嫌気性ガスが上昇水路に流入するのを防止するじゃま板３４を配置する。沈殿部の底２４´が図示のように円錐形に閉じ、仕切壁２８の下端が沈殿部の下半部の円錐形に上から短く沿って終る図１の実施例の場合は、仕切壁２８の下端から下に少し離して沈殿部の円錐形の下半部に対しほゞ直角なハ字形断面のじゃま板を沈殿部の下半部に固定する。又、仕切壁２８の下端が、沈殿部の円錐形に閉じた底の近くにまで沿って長く延びている図２の実施例の場合は仕切壁２８の下端の開口部から下に少し離して陣笠形のじゃま板を配置する。そして、各じゃま板３４にはその下に溜まる嫌気性ガスを処理槽の水面上に排気する排気管３５を設ける。
【００１２】
これにより、図１，図２の各実施例では、給水管２３から処理槽内に供給されて反応部２１中を上向流し、嫌気性汚泥層２２を流動状態に展開した原水（有機性排水）は、流動状態に展開する汚泥と接触して含有する有機物を嫌気性微生物で分解されて処理水となる。そして、処理水は分解により生成して浮上する嫌気性ガスに随伴し、一部の汚泥を伴って反応部２１から更に上向流する。
【００１３】
上向流する処理水の一部は上昇水路２９に下から流入して水路中を上昇し、又、処理水の残部は仕切壁２８の外を上昇し、この処理水に含まれている嫌気性ガスの気泡は処理槽の水面に浮上し、ガス抜き管２０´から外に放出される。上昇水路２９に流入して上昇する一部の処理水中に嫌気性ガスが含まれていても、嫌気性ガスは上昇水路の液面に浮上してガス抜き管２０´から放出されるので支障はないが、上昇水路の下端の下方に離してじゃま板３４を設けておくと、上昇水路に流入する処理水は、主にじゃま板に向かって上昇し、じゃま板の縁を迂回して来るものであるため、この処理水に含まれている嫌気性ガスはじゃま板の下に蓄積し、上昇水路２９に進入するのを防止でき、ガスと共に巻き上げられた汚泥が沈殿部に流入するのを大部分、防止できる。尚、じゃま板の下に蓄積した嫌気性ガスは排気管３５で処理槽の水面上に導かれ、ガス抜き管２０´から外に放出される。
【００１４】
上昇水路２９に流入した処理水は、図１の実施例では連通手段３０の水面上に開口した導水管３２の上端に溢入し、導水管中を下降して供給口３１から沈殿部２４の水中に接線方向に流入し、図２の実施例では上昇水路２９の途中に設けられた連通手段の供給口３１から沈殿部２４の水中に接線方向に流入する。沈殿部は上端部が処理槽内の水面上に突出し、底は閉じているため、仕切壁２８の外方を上向流する処理水や、浮上する嫌気性ガスによる水流の影響を受けることがないので、沈殿部に供給された処理水に含まれている汚泥は、それ自身の沈降性に従って沈殿部の底に自由沈降し、汚泥を分離した上澄み処理水は溢流装置２５に溢入し、排水管２６から槽外に流出する。
【００１５】
特に、上昇水路中の処理水は連通手段の接線方向の供給口３１によって沈殿部２４の水中に接線方向に流入するので、沈殿部内には旋回しながら上昇する渦流が生じ、処理水に混ざって沈殿部に入った汚泥はその渦流に乗って旋回し、渦流の求心力で沈殿部の中心に集まって沈殿部の底の中心部に沈降する。従って、沈殿部の外周付近から沈降する汚泥を底の中心部に集めるために、沈殿部の底の円錐の勾配を急にするとか、レーキなどを使用して機械的に集泥する必要がなくなる。このことは、沈殿部の底の円錐の勾配を緩くし、同じ高さの沈殿部内での汚泥の保持量を多くすることができるとか、汚泥の保持量を、円錐の勾配が急な従来の沈殿部と同じにすることによって沈殿部の高さを低くし、装置全体の高さを低くできることを意味する。尚、供給口３１の口径は、所望の流速の渦流が得られるように定めればよい。
【００１６】
更に、沈殿部内での旋回しながら上昇する渦流は慣性力により安定しているので、給水管２３から供給される原水の流入量の大小に基づき、上昇水路２９から連通手段３０で沈殿部２４に流入する処理水の流入量が変動しても、その変動を吸収することができるため、汚泥の沈降分離に悪影響は生じない。従って汚泥が溢流装置２５に流入することを確実に防止できるため、高負荷で安定な運転を行える。例えば、ＣＯＤ_cr容積負荷は汚泥保持濃度に比例するので、最大１００ｋｇＣＯＤ／ｍ³ ／日程度までの高負荷運転が可能になる。
【００１７】
そして、沈殿部２４の底に沈積した汚泥は、ポンプＰの運転により連続的、又は間欠的に返送管３３で反応部２１に戻す。返送管３１で反応部に返送する汚泥の量は、排水管２６で取出される上澄み処理水の水量の約１〜１０％程度が良い。
【００１８】
尚、図１，図２の実施例では仕切壁２８の上端は水面上に突出し、これにより上昇水路２９中を上昇する処理水の上昇流は乱されないので好ましいが、例えば図２の実施例において沈殿部の水中に処理水を接線方向に流入させる連通手段の接線方向の供給口３１の位置まで処理水が上昇水路中を上昇できるのであれば仕切壁２８の上端は水面下に位置していてもよい。
【００１９】
【発明の効果】
以上で明らかなように、本発明では、円筒形の沈殿部は下端が閉じ、沈殿部の内部は、沈殿部を囲む仕切壁の外を上昇する処理水や、浮上する嫌気性ガスの水流による影響を全く受けない。そして、沈殿部と、その外を囲む仕切壁との間に形成された上昇水路中を上昇する処理水は、連通手段が有する接線方向の供給口によって沈殿部の水中に接線方向に流入し、これにより沈殿部内には旋回しながら上昇する渦流が生じる。この渦流は慣性力により安定しているため、原水の流入量の大小に原因する沈殿部への処理水の流入量の変動を吸収し、処理水に混ざって沈殿部に流入した汚泥の沈降分離に悪影響を及ぼさないと共に、渦流の求心力により沈殿部に流入した汚泥は中心に集まり、沈殿部の底の中心に沈下し、沈殿部での汚泥の保持量を高めたり、装置の高さを低くすることに役立つ。こうして、汚泥を含まない処理水を沈殿部の溢流トラフから槽外に取出すことができ、処理水中に汚泥が流出するのを防止できる。従って有機性排水のＣＯＤcr負荷量が高く、嫌気性ガスの発生量が多くても、それ等に関係なく、汚泥が混ざらない上澄み処理水を採水することができる。そして、沈殿部上に沈降した汚泥は返送管で強制的に反応部に返送するため、反応部での嫌気性汚泥の量の不足を防止し、原水中の有機物を完全に生物処理することができる。
【図面の簡単な説明】
【図１】（Ａ）は本発明の嫌気性処理装置の第１実施例の概略縦断面図、（Ｂ）は（Ａ）のＡ−Ｂ線での断面図である。
【図２】（Ａ）は本発明の嫌気性処理装置の第２実施例の概略縦断面図、（Ｂ）は（Ａ）のＡ−Ｂ線での断面図である。
【図３】従来の嫌気性処理装置の概略縦断面図である。
【符号の説明】
２０処理槽
２１反応部
２２反応部の嫌気性汚泥層
２３反応部への給水管
２４沈殿部
２４´ 沈殿部の底
２５沈殿部の溢流装置
２６溢流装置からの排水管
２７排気管
２８仕切壁
２９上昇水路
３０連通手段
３１連通手段の接線方向の供給口
３３汚泥の返送管
３４じゃま板
３５排気管[0001]
BACKGROUND OF THE INVENTION
In the present invention, the organic matter in the organic waste water is a granule composed of anaerobic microorganisms constituting the sedimentation layer, and a self-granulated sludge (also simply referred to as sludge) which is a precursor (small particle size granule). The UASB type that finally decomposes into an anaerobic gas mainly composed of methane and carbon dioxide to remove organic matter, and separates the treated water from the generated anaerobic gas and sludge from the generated anaerobic gas ( (Upward sludge blanket type) Anaerobic treatment apparatus.
[0002]
[Prior art]
As shown in FIG. 3, a covered treatment tank 10 having a degassing pipe 11 at the top and an upper end projecting above the water surface in the tank, tilting below the water surface, and a lower end in the middle of the height in the tank. An inclined separation plate 12 positioned, a sludge settling chamber 13 provided by being separated in the tank by the inclined separation plate, a reaction chamber 14, and an anaerobic sludge layer 15 formed on the bottom of the reaction chamber; A water supply pipe 16 for supplying organic wastewater into the anaerobic sludge layer, an overflow trough 17 for treated water provided on the sludge sedimentation chamber in contact with an inclined separation plate, and an inside of the reaction chamber An anaerobic treatment apparatus for organic wastewater provided with a gas separation plate 18 provided at an inclination in the lower part of a sludge settling chamber is conventionally known. The planar shape of the treatment tank 10 may be a cylindrical shape or a rectangular tube shape. In the case of the cylindrical shape, the inclined separation plate 12 is a conical tube whose diameter is reduced downward, and the gas separation plate 18 is a Jinkasa shape. The conical plate of the inclined separation plate is composed of an upper half portion 12a and an upper portion having a lower half portion 12b whose diameter is slightly larger than the lower portion of the upper half portion, and the lower portion of the upper half portion and the upper portion of the lower half portion are inward and outward. A conical passage 12 ′ is formed between the concentric fittings and facing the circumferential surface of the Jinka-shaped gas separation plate. With such a configuration, the lower opening of the sludge settling chamber 13 is covered from below by the gas separation plate 18 leaving a flow path.
[0003]
When the raw water (organic wastewater) supplied from the water supply pipe 16 into the treatment tank rises in the anaerobic sludge layer, the organic matter contained is decomposed by the anaerobic microorganisms of the sludge constituting the sludge layer. The treated water flows upward in the reaction chamber 14 with some sludge as the anaerobic gas generated by the decomposition rises. A part of the treated water enters the sludge settling chamber 13 from the lower end of the sludge settling chamber 13 around the gas separation plate 18 and becomes an upward flow A rising in the chamber. The inlet at the lower end of the sludge settling chamber is blocked by the gas separation plate 18, and the treated water accompanied by the sludge does not directly flow upward into the sludge separating chamber, so that the gas is separated and the treated water flowing into the sludge settling chamber rises. The sludge contained in stream A is separated indoors, and the sludge falls on the gas separation plate from the inlet at the lower end of the precipitation chamber against the treated water flowing from below into the sludge precipitation chamber, and from around the gas separation plate It sinks on the anaerobic sludge layer 15. Accordingly, the treated water from which the sludge has been separated overflows into the overflow trough 17 and is taken out from the discharge pipe 19. Further, a part of the generated anaerobic gas gathers under the gas separation plate 18 and, if the treatment tank is a rectangular tube, from both ends of the gas separation plate having a chevron-shaped cross section to the outside of the precipitation chamber. It floats to the liquid level and is discharged from the degassing pipe 11.
[0004]
The remaining treated water containing sludge that did not flow into the sludge settling chamber rises to the upper part of the reaction chamber around the inclined separation plate 12 along with the anaerobic gas, and the anaerobic gas floats to the liquid level in the reaction chamber. Then, the gas is discharged from the degassing pipe 11.
The rising speed of the treated water rising to the upper part of the reaction chamber accompanying the anaerobic gas is determined by the CODcr load amount in the raw water, that is, the amount of the generated anaerobic gas, and the higher the CODcr load amount, the more the anaerobic gas is. As the amount of generated becomes larger, the rising speed of treated water becomes faster. Thus, the treated water that has released the anaerobic gas in the reaction chamber is formed as a reverse flow C of the upward flow B by the anaerobic gas along the outside of the inclined separation plate 12 in the reaction chamber, and the conical passage 12 below the inclined separation plate. The sludge contained in the treated water sinks onto the anaerobic sludge layer 15.
[0005]
[Problems to be solved by the invention]
The above-mentioned conventional apparatus can be sufficiently treated if the CODcr load is up to about 15 kg / COD / m ³ / day, but the COD load is 20 kg / COD / m ³ / day, or In the case of organic wastewater that is higher than that, since the amount of anaerobic gas produced is large, the upward flow B in the reaction chamber and the reverse flow C descending in the passage 12 ′ along the outside of the subsequent inclined separation plate are high speed. And collide violently on the gas separation plate 18 and partially enter the inside of the sedimentation chamber 13 as a reflective upward collision flow D to prevent or settle the sludge sedimentation in the sedimentation chamber. Sludge may flow into the overflow trough 17 and mix with the treated water taken out from the discharge pipe 19. That is, the reverse flow C that descends along the inclined separation plate 12 in the reaction chamber uses the reverse flow of the upward flow B that rises in the reaction chamber due to the anaerobic gas, and therefore rises as the CODcr load increases. An increase in the flow velocity of the flow B leads to an increase in the flow velocity of the reverse flow C, and as a result, the vertically upward collision flow D that rises in a reflective manner and stirs the chamber has an undeniable adverse effect, as described above. In addition, sedimentation of sludge in the sedimentation chamber is prevented, or sludge flows out to the discharge pipe 19. In addition, the sludge separated in the sludge settling chamber has to flow onto the gas separation plate against the flow of treated water that flows into the chamber and becomes the upward flow A, and therefore sludge stays in the sludge settling chamber and becomes anaerobic. The amount of sludge in the activated sludge layer 15 may be insufficient.
[0006]
[Means for Solving the Problems]
Therefore, the present invention reliably precipitates and separates sludge contained in the treated water without being affected by the upward flow of the treated water due to the anaerobic gas even when the CODcr load of the raw water is high, and forces the separated sludge. The problem of the above-mentioned conventional device is completely solved by returning it to the anaerobic sludge layer, and as an anaerobic treatment device for organic wastewater, an anaerobic sludge layer at the bottom and an organic substance in the sludge layer. The bottomed cylindrical sediment with the upper end protruding above the water surface in the tank, above the reaction section, in the inside of the treatment tank having a reaction pipe having a water supply pipe for supplying the wastewater in an upward flow An overflow device is provided in the upper part of the sedimentation part to take treated water out of the treatment tank. A partition wall is arranged around the sedimentation part with a space along the sedimentation part. Part of the treated water that rises from the reaction section flows in the space between the partition wall and the partition wall A rising channel is provided with communication means for communicating the rising channel with the inside of the settling section. The communicating means forms a tangential supply port for supplying treated water in the tangential direction inside the settling section, and A baffle plate is provided below the lower end of the water channel to prevent anaerobic gas from entering the ascending water channel, and sludge settled on the bottom of the precipitation unit is placed between the bottom of the precipitation unit and the reaction unit. It is characterized by having a return tube to be returned to.
[0007]
【Example】
1 and 2, 20 is a covered treatment tank having a degassing pipe 20 ′ at the top, 22 is an anaerobic sludge layer made of sludge formed inside the treatment tank, and 23 is the anaerobic sludge. This is a water supply pipe that feeds raw water (organic drainage) into the bed and flows upward, and the sludge that forms the anaerobic sludge layer is developed into a fluidized state up to the middle of the treatment tank by the raw water flowing upward. To do. The reaction part 21 is comprised in the lower half part in a processing tank by the feed pipe 23 of raw | natural water, and the anaerobic sludge layer 22 expand | deployed to a fluid state.
[0008]
Above the reaction part 21 inside the treatment tank, a bottomed cylindrical precipitation part 24 whose upper end protrudes above the water surface W in the tank is disposed. In the illustrated embodiment, the bottom 24 ′ of the settling portion 24 is closed in a conical shape having a V-shaped cross section, and is located above the reaction portion 21. An overflow device 25 for overflowing the treated water in the settling portion is provided in the upper portion of the settling portion, and the treated water overflowing in the overflow device is taken out of the tank through the drain pipe 26. The overflow device 25 is a trough provided along the upper inner periphery of the settling portion 24 in the embodiment of FIG. 1, and the bowl-shaped container provided at the center of the upper portion of the settling portion 24 in the embodiment of FIG. 2. It is.
[0009]
A partition wall 28 is arranged around the sedimentation section 24 at intervals along the sedimentation section 24, and a rising water channel 29 into which treated water rising from the reaction section 21 flows at the above-described distance between the sedimentation section and the partition wall. Form. And the communication means 30 which supplies the treated water of this ascending water channel 29 to the inside of a sedimentation part is provided, and the supply port 31 of the tangential direction which supplies treated water to the water of a sedimentation part in the communication part is formed in the communication means. The communication means 30 of the embodiment of FIG. 1 is provided in the ascending water channel 29, and is connected to a water conduit 32 for lowering the treated water overflowing from the water surface of the water channel, a lower end of the water conduit, and the wall of the sedimentation portion. The supply port 31 penetrates in the tangential direction. In addition, the communication means 30 of the embodiment of FIG. 2 is the supply port 31 which is attached to a hole formed in the wall of the settling portion and projects tangentially into the water of the settling portion.
[0010]
A return pipe 33 is provided between the bottom of the sedimentation section 24 and the reaction section 21 to return the sludge settled on the bottom of the sedimentation section to the reaction section. A pump P is connected to the return pipe 33, the pump is operated continuously or intermittently, and sludge is supplied to the reaction section from the bottom of the sedimentation section.
[0011]
Prevents anaerobic gas floating from the reaction unit 21 from flowing into the rising channel below the lower end of the rising channel 29 formed at the interval between the outer surface of the sedimenting unit and the inner surface of the partition wall surrounding the sedimenting unit. A baffle plate 34 is arranged. In the case of the embodiment of FIG. 1 in which the bottom 24 'of the sedimentation section closes in a conical shape as shown, and the lower end of the partition wall 28 ends along the conical shape of the lower half of the sedimentation section from above, the partition wall 28 A baffle plate having a cross-section that is substantially perpendicular to the lower half of the conical portion of the sedimentation section is fixed to the lower half of the sedimentation section. Further, in the case of the embodiment of FIG. 2 in which the lower end of the partition wall 28 extends long along the vicinity of the conical bottom of the sedimentation portion, it is slightly separated from the opening at the lower end of the partition wall 28. Place a Jinkasa-shaped baffle. Each baffle plate 34 is provided with an exhaust pipe 35 for exhausting the anaerobic gas accumulated under the baffle plate 34 onto the water surface of the treatment tank.
[0012]
1 and FIG. 2, the raw water (organic wastewater) that is supplied from the water supply pipe 23 into the treatment tank and flows upward in the reaction section 21 and develops the anaerobic sludge layer 22 in a fluidized state. ) Is treated with sludge that develops in a fluidized state and decomposes with anaerobic microorganisms to produce treated water. Then, the treated water is accompanied by the anaerobic gas that is generated by the decomposition and rises, and further flows upward from the reaction unit 21 with some sludge.
[0013]
A part of the treated water flowing upward flows into the ascending water channel 29 from below and rises in the water channel, and the remainder of the treated water rises outside the partition wall 28 and is anaerobic contained in the treated water. The bubble of the property gas floats on the water surface of the treatment tank and is discharged to the outside from the degassing pipe 20 ′. Even if anaerobic gas is contained in some of the treated water that flows into the ascending water channel 29 and rises, the anaerobic gas floats on the liquid surface of the ascending water channel and is released from the degassing pipe 20 '. Although there is no baffle plate 34 below the lower end of the ascending channel, the treated water that flows into the ascending channel rises mainly toward the baffle and bypasses the edge of the baffle plate Therefore, the anaerobic gas contained in the treated water accumulates under the baffle plate and can be prevented from entering the ascending water channel 29, and the sludge that is rolled up with the gas greatly flows into the sedimentation part. Part, can prevent. Incidentally, the anaerobic gas accumulated under the baffle plate is led to the water surface of the treatment tank by the exhaust pipe 35 and is released to the outside from the gas vent pipe 20 '.
[0014]
In the embodiment of FIG. 1, the treated water that has flowed into the ascending water channel 29 overflows into the upper end of the water conduit 32 that opens on the water surface of the communication means 30, descends in the water conduit, and passes from the supply port 31 to the precipitation unit 24. 2 flows into the water in the tangential direction, and flows into the water of the sedimentation section 24 in the tangential direction from the supply port 31 of the communication means provided in the middle of the rising water channel 29 in the embodiment of FIG. Since the sedimentation part has an upper end protruding above the water surface in the treatment tank and the bottom is closed, the sedimentation part may be affected by the treatment water flowing upward outside the partition wall 28 or the water flow caused by the anaerobic gas that rises. Therefore, the sludge contained in the treated water supplied to the sedimentation section freely settles at the bottom of the sedimentation section according to its own sedimentation property, and the supernatant treated water separated from the sludge overflows into the overflow device 25. Then, it flows out of the tank from the drain pipe 26.
[0015]
In particular, the treated water in the ascending water channel flows tangentially into the water of the sedimentation section 24 by the tangential supply port 31 of the communication means, so that a swirl that rises while swirling is generated in the sedimentation section and mixed with the treated water. The sludge that has entered the settling part swirls on the vortex, gathers at the center of the settling part by the centripetal force of the vortex, and settles at the center of the bottom of the settling part. Therefore, in order to collect the sludge that settles from the vicinity of the outer periphery of the sedimentation section in the center of the bottom, it is not necessary to steeply increase the gradient of the cone at the bottom of the sedimentation section or mechanically collect the mud using a rake or the like. . This means that the slope of the cone at the bottom of the sedimentation section can be relaxed, and the amount of sludge retained in the sedimentation section at the same height can be increased. By making it the same as the sedimentation section, it means that the height of the sedimentation section can be lowered and the overall height of the apparatus can be lowered. The diameter of the supply port 31 may be determined so that a vortex flow having a desired flow velocity can be obtained.
[0016]
Furthermore, since the swirl that rises while swirling in the settling part is stabilized by the inertial force, based on the amount of inflow of the raw water supplied from the water supply pipe 23, the communication means 30 connects the ascending water channel 29 to the settling part 24. Even if the inflow amount of the inflowing treated water fluctuates, the fluctuation can be absorbed, so that there is no adverse effect on the sludge settling separation. Accordingly, since it is possible to reliably prevent the sludge from flowing into the overflow device 25, a stable operation can be performed with a high load. For example, since the COD _cr volume load is proportional to the sludge retention concentration, a high load operation up to about 100 kg COD / m ³ / day is possible.
[0017]
And the sludge deposited on the bottom of the sedimentation part 24 is returned to the reaction part 21 by the return pipe 33 continuously or intermittently by the operation of the pump P. The amount of sludge that is returned to the reaction section by the return pipe 31 is preferably about 1 to 10% of the amount of supernatant treated water taken out by the drain pipe 26.
[0018]
In the embodiment shown in FIGS. 1 and 2, the upper end of the partition wall 28 protrudes above the water surface, which is preferable because the upward flow of treated water rising in the rising water passage 29 is not disturbed. For example, in the embodiment shown in FIG. The upper end of the partition wall 28 is located below the water surface so long as the treated water can rise up to the position of the supply port 31 in the tangential direction of the communication means for flowing the treated water into the tangential direction of the settling portion. Also good.
[0019]
【The invention's effect】
As is apparent from the above, in the present invention, the cylindrical sedimentation portion is closed at the lower end, and the interior of the sedimentation portion is caused by the treated water rising outside the partition wall surrounding the sedimentation portion or the flow of anaerobic gas that rises. Not affected at all. And the treated water rising in the rising water channel formed between the sedimentation part and the partition wall surrounding the outside flows tangentially into the water of the sedimentation part through the tangential supply port of the communication means, As a result, a swirl that rises while swirling is generated in the settling portion. Since this vortex is stabilized by the inertial force, it absorbs fluctuations in the amount of inflow of treated water into the sedimentation area due to the inflow of raw water, and settles and separates sludge that flows into the sedimentation area by mixing with the treated water. The sludge that has flowed into the sedimentation section due to the centripetal force of the vortex collects in the center and sinks to the center of the bottom of the sedimentation section, increasing the amount of sludge retained in the sedimentation section or reducing the height of the device. To help. Thus, the treated water that does not contain sludge can be taken out of the tank from the overflow trough of the sedimentation section, and sludge can be prevented from flowing into the treated water. Accordingly, even if the organic wastewater has a high CODcr load amount and a large amount of anaerobic gas is generated, it is possible to collect the supernatant treated water that does not mix sludge regardless of the amount of the generated anaerobic gas. And since the sludge settled on the sedimentation part is forcibly returned to the reaction part by the return pipe, the shortage of anaerobic sludge in the reaction part is prevented, and the organic matter in the raw water can be completely biologically treated. it can.
[Brief description of the drawings]
FIG. 1A is a schematic longitudinal sectional view of a first embodiment of an anaerobic treatment apparatus of the present invention, and FIG. 1B is a sectional view taken along line AB in FIG.
FIG. 2A is a schematic longitudinal sectional view of a second embodiment of the anaerobic treatment apparatus of the present invention, and FIG. 2B is a sectional view taken along line AB of FIG.
FIG. 3 is a schematic longitudinal sectional view of a conventional anaerobic treatment apparatus.
[Explanation of symbols]
20 treatment tank 21 reaction part 22 anaerobic sludge layer 23 of reaction part water supply pipe 24 to reaction part 24 sedimentation part 24 'bottom of sedimentation part 25 overflow apparatus 26 of sedimentation part drain pipe 27 from overflow apparatus exhaust pipe 28 partition Wall 29 Ascending water channel 30 Communication means 31 Tangential supply port 33 of the communication means Sludge return pipe 34 Baffle plate 35 Exhaust pipe

Claims

An upper end is located above the reaction part inside the treatment tank provided with a reaction part having an anaerobic sludge layer at the bottom and a water supply pipe for supplying organic wastewater into the sludge layer in an upward flow. The bottomed cylindrical sedimentation part which protruded on the water surface in the inside is arranged, and the overflow device for taking out treated water out of the processing tank is provided in the upper part of the sedimentation part, and the sedimentation part is around the sedimentation part. A partition wall is arranged along the interval, and the above-mentioned distance between the sedimentation part and the partition wall is a rising water channel into which a part of the treated water rising from the reaction part flows. The communication means is provided with a tangential supply port for supplying treated water in the tangential direction inside the settling portion, and anaerobic in the ascending water channel below the lower end of the ascending water channel. A baffle plate is installed to prevent the entry of sexual gases, and the sedimentation part is placed between the bottom of the precipitation part and the reaction part. Settled anaerobic treatment apparatus sludge in that a return pipe for returning the reaction section organic wastewater characterized by the.