JP2004202367A

JP2004202367A - Aerobic fermentation treatment apparatus

Info

Publication number: JP2004202367A
Application number: JP2002374536A
Authority: JP
Inventors: Hironoshin Kawabata; 洋之進川端; Megumi Yuzawa; 恩湯沢
Original assignee: Yamato Co Ltd
Current assignee: Yamato Co Ltd
Priority date: 2002-12-25
Filing date: 2002-12-25
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fermentation treatment apparatus in which materials to be treated such as organic sludge are promptly mixed inside a fermentation treatment tank and air is evenly sent into the materials to be treated, which has a simple structure and the maintenance and checking of which are easily carried out. <P>SOLUTION: The fermentation treatment tank is horizontal and cylindrical and has a port of charging the materials to be treated, a port of discharging treated materials and a plurality of platy stirring blades attached to a horizontal rotary shaft. Two sheets of platy stirring blades of a shape having a tilted face part formed by bending the top end part of the stirring blade at two stages form one set, and two or more sets thereof are attached to the rotary shaft with an angular shift of 90° to each other. Preferably each of two stirring blades has surfaces bent in opposite directions to each other and is shifted by 180° around the rotary shaft from the other. Further, compressed air is evenly sent in, by control of an automatic opening/closing valve, through a plurality of air blasting ports provided at the bottom part of the fermentation treatment tank in its longitudinal direction. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、微生物の作用を利用して有機汚泥等を発酵分解する好気発酵処理装置に関する。
【０００２】
【従来の技術】
有機汚泥等を微生物の作用によって発酵分解させるためには、発酵槽内の被処理物が適切な含水率を有し、かつ被処理物に通気性があることが要求される。被処理物が有機汚泥である場合には、発酵処理を行なうのに適した汚泥の含水率は６０％程度である。しかしながら、一般に回収された汚泥は多量の水分を含んでいるのが普通であり、し尿処理汚泥や下水処理汚泥などの有機汚泥をスクリュープレスなどで脱水処理したものであっても、脱水後の通常の含水率は８０％程度である。
【０００３】
そこで、このような汚泥を発酵処理装置に投入する前に、これらの汚泥の含水率を低下させるために、これらの高含水率の汚泥を発酵処理装置の中に残留させた含水率の低い既に処理済の堆積汚泥と混合して、含水率を６０％程度とすることが行なわれている。この場合には、発酵処理装置の投入口付近に滞留している新しい投入汚泥を、速やかに処理装置内部に移送し、効率よく処理済の堆積汚泥と混合させることが要求される。このような目的のために、例えば竪型円筒形の発酵処理装置において、攪拌羽根を回転させる回転軸の内部にスクリューコンベアーを設けた構造の処理装置とし、攪拌羽根とは別にこのスクリューコンベアーを回転させることによって投入汚泥と堆積汚泥の強制的な循環移送を行なう方法が提案されている（例えば、特許文献１参照）。しかし、このような方式の処理装置は構造が複雑となり高価であり、スクリューコンベアーに汚泥が詰まった場合には移送機能が停止してしまう可能性があるほか、スクリューコンベアーの点検が困難であったり、破損した場合にはその補修に手間がかかるなど、維持管理の負担が大きくなるという問題があった。
【０００４】
また、被処理物の通気性を改善するために、例えば処理槽の底部からコンプレッサーを用いて圧縮空気を送り込む方法が提案されている（例えば、特許文献２参照）。しかしながら、この方法では空気の送入口が処理槽の底部の中心に取り付けられているため、底部から空気が均一に送入されず、発酵汚泥の性状にばらつきが生ずるという問題があった。
【０００５】
【特許文献１】
特開２００１−２２５０３９号公報
【特許文献２】
特開昭５７−１２３８８２号公報
【０００６】
【発明が解決しようとする課題】
本発明は、発酵処理槽に投入された汚泥が速やかに内部に移送されて混合され、かつ発酵処理槽の底部から均一に空気を送入することができる、従来のものよりも簡単な構造で、かつ保守点検の容易な発酵処理装置を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
本発明者らは、従来の方法のこのような問題点を解決し、上記の課題を解決した発酵処理装置を開発すべく鋭意研究を行い、本発明を完成するに至った。
【０００８】
すなわち、本発明は、以下の内容をその要旨とするものである。
（１）被処理物の投入口、処理済みの被処理物の排出口、水平な回転軸に取り付けられた複数の板状の攪拌羽根を有する横型円筒形の発酵処理槽において、羽根の先端部を２段階に折り曲げた傾斜面部分を有する板状の攪拌羽根の２枚を１組として、互いに角度を９０度ずらして回転軸に２組以上取り付けたことを特徴とする、好気発酵処理装置。
（２）２枚の攪拌羽根が、折り曲げ面を互いに反対方向とし、回転軸に対して１８０°反対側の位置関係であることを特徴とする、前記（１）記載の好気発酵処理装置。
（３）２枚の攪拌羽根が、その取り付け部で回転軸にボルトとナットで固定されていることを特徴とする、前記（１）または（２）記載の好気発酵処理装置。
（４）横型円筒形の発酵処理槽の底部に、その長手方向に圧縮空気の送入用の複数の送気口を設け、これらの送気口に自動開閉弁を介してコンプレッサーに接続した空気配管を接続していることを特徴とする、前記（１）ないし（３）のいずれかに記載の好気発酵処理装置。
（５）送気口が、攪拌羽根の回転方向に対して逆の方向に傾斜して取り付けられていることを特徴とする、前記（４）記載の好気発酵処理装置。
【０００９】
【発明の実施の形態】
以下に、本発明を図面を用いて更に具体的に説明する。
図１は本発明の好気発酵処理装置の発酵処理槽１の縦断面図であり、図２は発酵処理槽１内に取り付けた攪拌羽根部分のモーター側から見た断面図であり、図３は攪拌羽根１９の詳細図、図４は攪拌羽根２０の詳細図、図５は発酵処理槽１の送気口の取り付け説明図である。
発酵処理槽１は、横型円筒形であり、円筒の中心部に回転軸１３を有し、この回転軸１３の一端は側壁５に着脱可能に固定された軸受け１４を介し、また回転軸の他端は発酵処理槽１の他端の側壁６に着脱可能に固定された軸受け１５を介して回転自在に取り付けられている。回転軸１３は攪拌羽根の取り付けやすさの点から、その断面形状が正方形のものが好ましい。側壁６にはモーターベース１０により駆動用のモーター１１が取り付けられ、回転軸１３はカップリングによってこのモーター１１と連結されている。
【００１０】
この回転軸１３には、攪拌羽根の先端部を２段階に折り曲げた形状とした板状の攪拌羽根１９を、その２枚を１組として、２組以上が互いに角度を９０度ずらして取り付けられている。この板状の攪拌羽根１９は、図３に示すように、取り付けられた回転軸１３から直角に延伸する板状部分１９ａと、その先端部の１／２〜１／４の部分で板状部分１９ａに対して２０°〜４０°の角度で斜めに折り曲げられた第１の傾斜面部分１９ｂと、その先で板状部分１９ａに対して９０°の角度に折り曲げられた第２の傾斜面部分１９ｃと、回転軸１３に固定するための取り付け部１９ｄとから成っている。この攪拌羽根１９及び２０の先端（１９ｃの折り曲げた側面）と発酵処理槽の内壁２と間は、ほとんど隙間がなく、通常５ｍｍから１０ｍｍ程度の隙間となるように取り付ける。第２の傾斜面部分１９ｃは、図３の側面図に示すように、その側面が板状部分１９ａの側面に対して直角、即ち９０°となっており、回転軸１３と並行になっている。
【００１１】
この攪拌羽根１９は、図３に示すように、例えば、その展開図に示す形状の金属などの板状の材料を第１の折り線イで折り曲げて板状部分１９ａと第１の傾斜面部分１９ｂを形成し、さらに第２の折り線ロで折り曲げて第２の傾斜面部分１９ｃを形成して、図３に示す形状の攪拌羽根とする。
このような形状の攪拌羽根を使用することにより、この羽根の回転とともに第１の傾斜面部分１９ｂによって被処理物をモーター側かその反対側へ押出すスライド効果を発揮し、第２の傾斜面部分１９ｃによって被処理物を処理槽の底部から上方へ掻き上げる攪拌効果を発揮する。
【００１２】
また、発酵処理槽１の両側壁５および６に面した位置に取り付ける攪拌羽根２０は図４に示す形状のものとすることが好ましい。即ち、この位置においては発酵処理槽１の側壁の方向へ被処理物を移動させる必要はなく、発酵処理槽１の側壁と反対の処理槽の内部の方向に被処理物を移動させる必要があるため、２枚の攪拌羽根のうち片方は攪拌羽根１９と同一の形状とし、もう一方は攪拌羽根２０のような形状とする。この攪拌羽根２０は、図４に示すように、攪拌羽根１９の第１の傾斜面部分１９ｂに相当する部分がなく、回転軸１３から直角に延伸する板状部分２０ａと、その先端部で板状部分２０ａに対して９０°の角度に折り曲げられた第２の傾斜面部分２０ｂと、回転軸１３に固定するための取り付け部２０ｃとから成っている。
このような２枚１組の攪拌羽根を回転させることにより、攪拌羽根２０によって被処理物が発酵処理槽１の底部からかき上げられて上方へ移動すると共に、もう一つの攪拌羽根１９により発酵処理槽１の内部の方向へ移動させられるように作用する。
【００１３】
このような形状の２枚の攪拌羽根１９および２０が互いに折り曲げた面が反対側となるような位置関係で、回転軸に対してそれぞれの板状部分が垂直になるように対向して取り付けられている。即ち、この２枚１組の攪拌羽根１９は、折り曲げ面を互いに反対方向とし、回転軸に対して１８０°反対側の位置関係で回転軸に取り付けられることが好ましい。攪拌羽根の回転軸への取り付けは、羽根の取替えや保守点検のために容易に取り外すことができるように着脱自在に取り付けることが好ましく、例えばボルトとナットによって回転軸に固定することが好ましい。発酵処理槽１の中でのこの２枚１組の攪拌羽根の取り付け間隔は発酵処理槽１の大きさにも依存するが、一般的に５０〜３００ｍｍの間隔で、好ましくは１５０〜２００ｍｍの間隔で取り付ける。実際には、隣り合う羽根の先端部分の間の間隔はほとんどない状態が好ましく、２０〜５０ｍｍであることが好ましい。また、この攪拌羽根の回転数は、発酵処理槽１の大きさや処理する汚泥の量によっても変わるが、一般的に毎分０．５〜５回転、好ましくは毎分１〜２回転の回転数で処理する。
【００１４】
発酵処理槽１は、その側端部の上部に被処理物である汚泥の投入口７を有し、下部に処理の終わった後の被処理物の排出口８を有する。また、その内部は中空に形成され、内壁２と外壁３の隙間には断熱剤４を有している。また、発酵処理槽１の底部には、内部を加熱するための加熱手段として例えばパイプヒーター１２が一様に張り巡らされている。発酵処理槽１の投入口と反対側の上部空間には吸引口９が形成されており、外部の吸引ファンに接続され、発酵処理槽１の中の空気を吸引し、臭気漏れを防ぐために空間部がわずかに負圧のなるようにしている。
【００１５】
発酵処理槽１の底部にはその長手方向にコンプレッサーからの圧縮空気を送入する為の送気口１６が一定間隔で形成されている。この送気口１６にはそれぞれ自動開閉弁１７が取り付けられ、これに空気配管１８が取り付けられ、さらにコンプレッサーに接続している。
この送気口１６は、発酵処理槽１の壁面に垂直に取り付けてもよいが、攪拌羽根の回転等によってこの送気口に被処理物の汚泥が詰まり、空気の送入が妨げられるおそれがある。このようなトラブルを防止するために、送気口１６は発酵処理槽１の壁面に対して垂直ではなく、図５に示すように攪拌羽根の回転方向に対して逆方向に傾斜した状態に取り付けることが好ましい。このように送気口１６を取り付けることによって、発酵処理槽１の運転を続け、攪拌羽根が回転しても送気口１６の詰まりが防止することができる。
【００１６】
次に、本発明の好気発酵処理装置を用いた有機汚泥の発酵処理の方法について説明する。
発酵処理槽１の内部には、その前のバッチの処理として既に発酵処理を行った水分がおよそ４０質量％程度の被処理物の汚泥をその容積の２０〜４０％の量で堆積汚泥として残留させてある。モーターを起動して攪拌羽根を回転し、この堆積汚泥を攪拌する。攪拌羽根の回転数は、毎分０．５〜５．０回転であり、好ましくは毎分１．０〜２．０回転であり、もっとも好ましくは毎分１．５回転程度である。また、吸引口９を外部のファンに接続して内部の吸引を開始し、自動開閉弁１７を開いて送気口１６から圧縮空気の送入を開始する。ここに、予め脱水処理を行なった水分がおよそ８０質量％程度の処理用汚泥を投入口７から、発酵処理槽１の容積のおよそ６０〜８０％となる量まで少量ずつ投入する。処理用汚泥の投入を完了後、攪拌羽根の回転を続けて処理用汚泥の発酵処理を回分方式で行なう。装置の大きさにもよるが、汚泥の投入には１０〜５０時間、好ましくは２０〜４０時間をかけて徐々に行い、発酵処理にはその前後の加熱及び冷却時間も含めて、５日〜２０日、好ましくは１週間〜２週間の時間をかけて行なう。
【００１７】
攪拌羽根の回転に伴って、内部の汚泥は攪拌羽根１９の第２の傾斜面部分１９ｃによって上方に持ち上げられて落下し、投入された汚泥はその攪拌作用によって堆積汚泥と混合されるとともに、攪拌羽根１９の傾斜した部分である第１の傾斜面部分１９ｂの作用によって前方へ押出される。即ち、図１においては、攪拌羽根１９のうちの上部の羽根によって被処理物は右側、即ち矢印Ａのモーター方向へ押出され、下部の羽根によって左側、即ち矢印Ｂの排出口方向へ押出され、攪拌羽根がさらに回転することによりその後にはこれとは逆方向の移動が起こり、被処理物が１９ｃの部分による掻き上げ効果とともに、左と右の方向に移動するという運動によって攪拌が行なわれる。図２は、図１において中央部の攪拌羽根１９をモーター側から見たものであるが、２枚１組の攪拌羽根１９が互いに９０°ずれて攪拌軸１３に取り付けられており、これが矢印Ｃの方向に回転することによって被処理物である汚泥が上方へ掻きあげられると同時に、紙面の前方または後方の方向へ押出されるという作用を受ける。
【００１８】
また、この発酵処理を行なう間、コンプレッサーから空気配管１８、発酵処理槽１の底部に設けた送気口１６を通して圧縮空気を送入する。この場合、送気口１６の下に取り付けた自動開閉弁１７の開閉をコントロールして、一つの自動開閉弁のみを開き、残りの自動開閉弁は閉じた状態として空気を送入し、このような送気を一端の弁から他端の弁に向かって順次、繰り返して行なうというパターンで圧縮空気の送入を行なうことが好ましい。このような空気の送入を行なうことによって、発酵処理槽１内の被処理物全体に空気が均一に吹き込まれ、発酵処理が効率よく行なわれる。
更に、この発酵処理の間、発酵処理槽１の底部に設けたパイプヒーターなどの加熱手段によって被処理物を加熱し、微生物の活動に伴う発熱と併せて、６０〜８０℃、好ましくは６５〜７０℃の温度に加熱し、２日以上保持することが好ましい。
【００１９】
以上述べたように、攪拌羽根の回転を続けて少なくとも２日、好ましくは数日間の発酵処理を行なうことにより、内部の被処理物である汚泥は均一に攪拌されるとともに、水分が約６０％、温度が約６５〜７０℃に調節され、同時に発酵処理槽１の底部から圧縮空気が被処理物全体に均一の状態で吹き込まれるので、微生物の活動が活発になり、発酵処理槽１全体で微生物による発酵が効率よく行なわれる。
また、本発明の発酵処理装置は、上述のように比較的簡単な構造であるため比較的低コストで強度が大きなものすることができる。攪拌羽根１９を一定間隔で９０°づつずらして配置しているため汚泥の混合時の負荷も分散され、耐久性に優れ、また攪拌羽根の取り付けと取り外しが容易な構造であり、発酵処理装置の保守点検や修理が容易で維持管理の負担を軽減できるというメリットも有する。
【００２０】
【実施例】
次に実施例により本発明をさらに詳細に説明するが、本発明は以下に示す実施例に限定されるものではない。なお、実施例中、「％」は、特別に記載しない限り質量基準である。
【００２１】
実施例：
図１に示す好気発酵処理装置を用いて下水汚泥の発酵処理を行なった。内容積が２ｍ３の発酵処理槽１の内部に、水分が約４０％の発酵処理済の汚泥をその容積が発酵処理槽１の約４０容積％となる量で残した。発酵処理槽１の底部のパイプヒーターに通電して加熱を開始し、外部ファンを動かして吸引口９から発酵処理槽１の上部の空間部を吸引した。また、自動開閉弁１７の開閉をコントロールして一つずつ自動開閉弁が順番に開くように設定し、送気口１６からコンプレッサーの圧縮空気を発酵処理槽１の内部に送入した。この状態でモーターのスイッチを入れて、攪拌羽根１９および２０を毎分１．５回転の回転数で回転させて、攪拌を開始した。
ここに、予めスクリュープレス脱水機で脱水した，水分が約８０％の発酵処理用の下水汚泥の約４００Ｋｇを投入口７から約１６時間かけて徐々に投入した。投入完了後も、攪拌羽根を毎分１．５回転で回転させて攪拌を続け、パイプヒーターで加熱し、微生物の活動に伴う発熱と併せて、汚泥の温度が６５℃以上となるように調節し２日間以上保持した。送気口１６から圧縮空気を送入しつつ、攪拌羽根を１分間回転、９分間停止という間欠運転で回転させて、１週間この状態で汚泥の発酵処理を行なった。汚泥温度が６５℃以上で２日間以上加熱するが、汚泥中の水分が４０％以下になった場合は、パイプヒーターの加熱を停止した。発酵処理が終了した後、圧縮空気の送入を続けながらパイプヒーターのスイッチを切って回転を続け、発酵処理槽１を放置冷却した。ほぼ室温に冷却した後、動力により発酵処理槽１のモーター側を持ち上げて、排出口８を開いて処理済の汚泥を取り出した。
得られた処理済の汚泥は、水分が約４０％で臭気がほとんどなく、発酵処理が良好に行なわれたことがわかった。また、発酵処理後の汚泥を分析したところ、下水汚泥堆肥の品質基準及び汚泥発酵肥料許容含有率値を十分に満たしている品質であった。
【００２２】
【発明の効果】
本発明の好気発酵処理装置は、その攪拌羽根が特殊な形状を有するものであるので、内部の被処理物が効率よく攪拌され、特に左右方向と上下方向への被処理物の移動の作用があるため、被処理物の発酵処理を効率よく行うことができる。また、その構造が比較的簡単であり、攪拌羽根の取り付けや取り外しも簡単に行なうことができるので、比較的低いコストで耐久性の高い装置とすることができ、かつ装置の保守点検や修理が容易である。
更に、好気発酵処理装置の底部から圧縮空気を、装置内での偏りがなく均一に送入することができるので、高い効率で発酵処理を行なうことができる。
【図面の簡単な説明】
【図１】本発明の好気発酵処理装置の垂直断面図である。
【図２】発酵処理槽１内のモーター側から見た攪拌羽根の正面図である。
【図３】攪拌羽根１９の展開図、正面図および側面図である。
【図４】攪拌羽根２０の展開図、正面図および側面図である。
【図５】発酵処理槽１の送気口２２の取り付け説明図である。
【符号の説明】
１．発酵処理槽
２．内壁
３．外壁
４．断熱材
５．側壁
６．側壁
７．投入口
８．排出口
９．吸引口
１０．モーターベース
１１．モーター
１２．パイプヒーター
１３．回転軸
１４．軸受け
１５．軸受け
１６．送気口
１７．自動開閉弁
１８．空気配管
１９．攪拌羽根（２段折）
１９ａ．板状部分
１９ｂ．第１の傾斜面部分
１９ｃ．第２の傾斜面部分
１９ｄ．取り付け部
２０．攪拌羽根（１段折）
２０ａ．板状部分
２０ｂ．第２の傾斜面部分
２０ｃ．取り付け部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aerobic fermentation treatment apparatus that fermentes and decomposes organic sludge and the like using the action of microorganisms.
[0002]
[Prior art]
In order to ferment and decompose organic sludge and the like by the action of microorganisms, it is required that the material to be treated in the fermenter has an appropriate moisture content and that the material to be treated has air permeability. When the material to be treated is an organic sludge, the water content of the sludge suitable for performing the fermentation treatment is about 60%. However, generally, collected sludge generally contains a large amount of water, and even if organic sludge such as human waste treated sludge or sewage treated sludge is subjected to dehydration treatment using a screw press or the like, the sludge is usually removed. Has a moisture content of about 80%.
[0003]
Therefore, before introducing such sludge into the fermentation treatment apparatus, in order to reduce the moisture content of these sludges, these sludges having a high moisture content remain in the fermentation treatment apparatus. It has been practiced to mix with the treated sediment sludge to make the water content about 60%. In this case, it is required that new sludge accumulated near the inlet of the fermentation treatment device be promptly transferred into the treatment device and efficiently mixed with the treated sludge. For this purpose, for example, in a vertical cylindrical fermentation processing apparatus, a processing apparatus having a structure in which a screw conveyor is provided inside a rotating shaft for rotating the stirring blade, and this screw conveyor is rotated separately from the stirring blade There has been proposed a method of forcibly circulating and transferring input sludge and sedimentary sludge by causing the sludge to flow (for example, see Patent Document 1). However, such a processing apparatus has a complicated structure and is expensive, and when the screw conveyor is clogged with sludge, the transfer function may be stopped, and it may be difficult to inspect the screw conveyor. In the case of damage, there is a problem that the burden of maintenance and management is increased, for example, it takes time to repair it.
[0004]
In addition, in order to improve the air permeability of an object to be processed, a method has been proposed in which compressed air is sent from the bottom of a processing tank using a compressor, for example (see Patent Document 2, for example). However, in this method, since the air inlet is attached to the center of the bottom of the treatment tank, air is not uniformly fed from the bottom, and there is a problem that the properties of the fermented sludge vary.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2001-225039 [Patent Document 2]
JP-A-57-123882
[Problems to be solved by the invention]
The present invention has a simpler structure than the conventional one, in which the sludge put into the fermentation tank can be quickly transferred to the inside and mixed, and air can be uniformly fed from the bottom of the fermentation tank. It is another object of the present invention to provide a fermentation treatment apparatus which is easy to maintain and inspect.
[0007]
[Means for Solving the Problems]
The present inventors have made intensive studies to solve such problems of the conventional method and to develop a fermentation treatment apparatus that has solved the above-mentioned problems, and have completed the present invention.
[0008]
That is, the present invention has the following contents as its gist.
(1) In a horizontal cylindrical fermentation tank having a plurality of plate-shaped stirring blades attached to a horizontal rotating shaft, a leading end portion of the blades. An aerobic fermentation treatment apparatus characterized in that two sets of plate-shaped stirring blades having inclined surface portions obtained by bending the two sets of blades are set as one set, and two or more sets are attached to a rotating shaft at an angle of 90 degrees from each other. .
(2) The aerobic fermentation treatment apparatus according to the above (1), wherein the two stirring blades have bent surfaces in mutually opposite directions and have a positional relationship of 180 ° opposite to the rotation axis.
(3) The aerobic fermentation treatment apparatus according to the above (1) or (2), wherein the two stirring blades are fixed to the rotating shaft with bolts and nuts at their mounting portions.
(4) At the bottom of the horizontal cylindrical fermentation treatment tank, a plurality of air inlets for supplying compressed air are provided in the longitudinal direction thereof, and the air connected to the compressor via an automatic opening / closing valve is provided at these air inlets. The aerobic fermentation treatment apparatus according to any one of (1) to (3), wherein a pipe is connected.
(5) The aerobic fermentation treatment device according to (4), wherein the air supply port is attached to be inclined in a direction opposite to the rotation direction of the stirring blade.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a fermentation treatment tank 1 of the aerobic fermentation treatment apparatus of the present invention, and FIG. 2 is a sectional view of a stirring blade portion mounted in the fermentation treatment tank 1 as viewed from a motor side. 4 is a detailed view of the stirring blade 19, FIG. 4 is a detailed view of the stirring blade 20, and FIG.
The fermentation tank 1 has a horizontal cylindrical shape, and has a rotating shaft 13 at the center of the cylinder. One end of the rotating shaft 13 is provided via a bearing 14 detachably fixed to the side wall 5. The end is rotatably attached via a bearing 15 detachably fixed to the side wall 6 at the other end of the fermentation treatment tank 1. The rotating shaft 13 preferably has a square cross section from the viewpoint of easy attachment of the stirring blade. A motor 11 for driving is attached to the side wall 6 by a motor base 10, and the rotating shaft 13 is connected to the motor 11 by a coupling.
[0010]
Two or more sets of plate-shaped stirring blades 19 each having a shape obtained by bending the tip of the stirring blade in two stages are attached to the rotating shaft 13 with two or more sets thereof being shifted by 90 degrees from each other. ing. As shown in FIG. 3, the plate-like stirring blade 19 has a plate-like portion 19a extending at a right angle from the attached rotating shaft 13, and a plate-like portion formed by 1/2 to 1/4 of the tip portion. A first inclined surface portion 19b bent obliquely at an angle of 20 ° to 40 ° with respect to 19a, and a second inclined surface portion bent forward at an angle of 90 ° with respect to the plate-like portion 19a 19c and a mounting portion 19d for fixing to the rotating shaft 13. There is almost no gap between the tip of each of the stirring blades 19 and 20 (the bent side surface of 19c) and the inner wall 2 of the fermentation treatment tank, and the gap is usually set to be about 5 mm to 10 mm. As shown in the side view of FIG. 3, the side surface of the second inclined surface portion 19 c is perpendicular to the side surface of the plate-shaped portion 19 a, that is, 90 °, and is parallel to the rotation axis 13. .
[0011]
As shown in FIG. 3, for example, the stirring blade 19 is formed by bending a plate-like material such as a metal having a shape shown in the developed view at a first fold line a to form a plate-like portion 19a and a first inclined surface portion. 19b is formed, and further bent at the second folding line B to form a second inclined surface portion 19c to obtain a stirring blade having a shape shown in FIG.
By using the stirring blade having such a shape, the first inclined surface portion 19b exerts a sliding effect of pushing out the object to be processed to the motor side or the opposite side with the rotation of the blade and the second inclined surface. The portion 19c exerts an agitating effect of lifting the object to be processed upward from the bottom of the processing tank.
[0012]
Further, it is preferable that the stirring blade 20 attached to the position facing the side walls 5 and 6 of the fermentation treatment tank 1 has a shape shown in FIG. That is, at this position, it is not necessary to move the article to be processed in the direction of the side wall of the fermentation tank 1, but it is necessary to move the article in the direction inside the processing tank opposite to the side wall of the fermentation tank 1. Therefore, one of the two stirring blades has the same shape as the stirring blade 19, and the other has a shape like the stirring blade 20. As shown in FIG. 4, the stirring blade 20 has a plate-like portion 20 a that does not have a portion corresponding to the first inclined surface portion 19 b of the stirring blade 19 and extends at a right angle from the rotation shaft 13, It comprises a second inclined surface portion 20b bent at an angle of 90 ° with respect to the shape portion 20a, and a mounting portion 20c for fixing to the rotating shaft 13.
By rotating such a pair of stirring blades, the object to be processed is lifted up from the bottom of the fermentation treatment tank 1 by the stirring blades 20 and moves upward, and the fermentation treatment is performed by another stirring blade 19. It acts so that it can be moved in the direction of the inside of the tank 1.
[0013]
The two stirring blades 19 and 20 having such a shape are mounted facing each other such that their plate-shaped portions are perpendicular to the rotation axis in a positional relationship such that the surfaces on which the stirring blades are bent are opposite to each other. ing. That is, it is preferable that the pair of the stirring blades 19 be attached to the rotary shaft in a positional relationship of 180 ° opposite to the rotary shaft, with the bent surfaces being opposite to each other. It is preferable that the stirring blade is attached to the rotating shaft so that the stirring blade can be easily removed for replacement or maintenance and inspection. For example, it is preferable that the stirring blade is fixed to the rotating shaft with a bolt and a nut. The mounting interval of the pair of stirring blades in the fermentation treatment tank 1 depends on the size of the fermentation treatment tank 1, but is generally 50 to 300 mm, preferably 150 to 200 mm. Attach with In practice, it is preferable that there is almost no space between the tip portions of the adjacent blades, and it is preferable that the distance be 20 to 50 mm. The rotation speed of the stirring blade varies depending on the size of the fermentation tank 1 and the amount of sludge to be treated, but is generally 0.5 to 5 rotations per minute, preferably 1 to 2 rotations per minute. To process.
[0014]
The fermentation tank 1 has an inlet 7 for sludge as an object to be treated at an upper portion of a side end thereof, and an outlet 8 for an object to be treated after the treatment is completed at a lower portion. Further, the inside is formed to be hollow, and a heat insulating agent 4 is provided in a gap between the inner wall 2 and the outer wall 3. Further, for example, a pipe heater 12 is uniformly spread around the bottom of the fermentation treatment tank 1 as a heating means for heating the inside. A suction port 9 is formed in the upper space on the opposite side of the input port of the fermentation treatment tank 1 and is connected to an external suction fan to suck air in the fermentation treatment tank 1 to prevent odor leakage. The section has a slight negative pressure.
[0015]
At the bottom of the fermentation treatment tank 1, air supply ports 16 for supplying compressed air from a compressor are formed at regular intervals in the longitudinal direction. An automatic opening / closing valve 17 is attached to each of the air supply ports 16, and an air pipe 18 is attached to the automatic opening / closing valve 17, and further connected to a compressor.
The air supply port 16 may be vertically attached to the wall surface of the fermentation treatment tank 1. However, there is a possibility that the air supply port may be clogged with sludge of the material to be treated due to rotation of the stirring blade or the like, thereby preventing air from being supplied. is there. In order to prevent such troubles, the air supply port 16 is not perpendicular to the wall surface of the fermentation treatment tank 1, but is attached in a state inclined in a direction opposite to the rotation direction of the stirring blade as shown in FIG. Is preferred. By attaching the air supply port 16 in this way, the operation of the fermentation treatment tank 1 can be continued, and the air supply port 16 can be prevented from being clogged even when the stirring blade rotates.
[0016]
Next, a method of fermenting organic sludge using the aerobic fermentation treatment apparatus of the present invention will be described.
Inside the fermentation treatment tank 1, the sludge of the material to be treated, which has been subjected to the fermentation treatment as a treatment of the previous batch and has a water content of about 40% by mass, remains as sedimentary sludge in an amount of 20 to 40% of its volume. Let me do it. The motor is started and the stirring blade is rotated to stir the accumulated sludge. The rotation speed of the stirring blade is 0.5 to 5.0 rotations per minute, preferably 1.0 to 2.0 rotations per minute, and most preferably about 1.5 rotations per minute. Further, the suction port 9 is connected to an external fan to start suction inside, and the automatic opening / closing valve 17 is opened to start feeding compressed air from the air supply port 16. Here, treatment sludge that has been previously dehydrated and has a water content of about 80% by mass is introduced little by little from the inlet 7 to an amount of about 60 to 80% of the volume of the fermentation tank 1. After completion of the introduction of the processing sludge, the rotation of the stirring blade is continued, and the fermentation treatment of the processing sludge is performed in a batch mode. Although it depends on the size of the apparatus, sludge is introduced gradually for 10 to 50 hours, preferably 20 to 40 hours, and the fermentation treatment includes heating and cooling time before and after 5 days to 5 days. It is carried out over a period of 20 days, preferably one to two weeks.
[0017]
With the rotation of the stirring blade, the sludge inside is lifted upward by the second inclined surface portion 19c of the stirring blade 19 and falls, and the inputted sludge is mixed with the deposited sludge by the stirring action, and is stirred. The blade 19 is pushed forward by the action of a first inclined surface portion 19b which is an inclined portion of the blade 19. That is, in FIG. 1, the object to be processed is pushed out to the right by the upper blade of the stirring blade 19, that is, in the direction of the motor shown by arrow A, and is pushed out by the lower blade to the left, that is, in the direction of the outlet shown by arrow B. The rotation of the stirring blade further causes the movement in the opposite direction thereafter, and the stirring is performed by the movement in which the object moves in the left and right directions together with the scraping effect of the portion 19c. FIG. 2 shows the stirring blade 19 at the center in FIG. 1 viewed from the motor side. A pair of stirring blades 19 are attached to the stirring shaft 13 at 90 ° offset from each other. , The sludge, which is the object to be treated, is swept up and simultaneously extruded in the forward or backward direction on the paper.
[0018]
During the fermentation process, compressed air is supplied from the compressor through the air pipe 18 and the air supply port 16 provided at the bottom of the fermentation tank 1. In this case, the opening and closing of the automatic opening / closing valve 17 attached below the air supply port 16 is controlled so that only one automatic opening / closing valve is opened, and the remaining automatic opening / closing valve is closed so that air is supplied. It is preferable that the compressed air be supplied in such a pattern that the necessary air supply is performed repeatedly from the valve at one end to the valve at the other end. By introducing such air, air is uniformly blown into the entire treatment object in the fermentation treatment tank 1, and the fermentation treatment is performed efficiently.
Further, during this fermentation treatment, the object to be treated is heated by a heating means such as a pipe heater provided at the bottom of the fermentation treatment tank 1 and is heated to 60 to 80 ° C., preferably 65 to 80 ° C., together with the heat generated by the activity of microorganisms. It is preferable to heat to a temperature of 70 ° C. and hold for 2 days or more.
[0019]
As described above, by performing the fermentation treatment for at least two days, and preferably several days while continuing the rotation of the stirring blade, the sludge as the object to be treated is uniformly stirred and the water content is reduced to about 60%. The temperature is adjusted to about 65 to 70 ° C., and at the same time, the compressed air is blown from the bottom of the fermentation treatment tank 1 in a uniform state to the whole object to be treated, so that the activity of microorganisms becomes active and Fermentation by microorganisms is performed efficiently.
Further, the fermentation treatment apparatus of the present invention has a relatively simple structure as described above, so that the strength can be increased at a relatively low cost. Since the stirring blades 19 are staggered by 90 ° at regular intervals, the load at the time of mixing the sludge is dispersed, the durability is excellent, and the installation and removal of the stirring blades is easy. It also has the advantage that maintenance and inspections and repairs are easy and the burden of maintenance can be reduced.
[0020]
【Example】
Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples described below. In Examples, "%" is based on mass unless otherwise specified.
[0021]
Example:
The sewage sludge was fermented using the aerobic fermentation treatment apparatus shown in FIG. Fermentation-treated sludge having a water content of about 40% was left in the fermentation treatment tank 1 having an internal volume of 2 m3 in such an amount that the volume became about 40% by volume of the fermentation treatment tank 1. The pipe heater at the bottom of the fermentation tank 1 was energized to start heating, and the external fan was operated to suck the space above the fermentation tank 1 from the suction port 9. Further, the opening and closing of the automatic opening and closing valve 17 was controlled so that the automatic opening and closing valves were opened one by one in order, and the compressed air of the compressor was fed into the fermentation treatment tank 1 from the air supply port 16. In this state, the motor was turned on, and the stirring blades 19 and 20 were rotated at a speed of 1.5 revolutions per minute to start stirring.
Here, about 400 kg of sewage sludge for fermentation treatment having a water content of about 80%, which had been previously dehydrated by a screw press dehydrator, was gradually introduced from the introduction port 7 over about 16 hours. After completion of the charging, the stirring blade is rotated at 1.5 revolutions per minute to continue stirring, heated by a pipe heater, and adjusted so that the temperature of the sludge becomes 65 ° C. or higher, together with the heat generated by the activity of microorganisms. And kept for more than 2 days. While supplying compressed air from the air supply port 16, the stirring blade was rotated in an intermittent operation of rotating for 1 minute and stopping for 9 minutes, and fermentation treatment of sludge was performed in this state for one week. The sludge was heated at a temperature of 65 ° C. or more for 2 days or more. When the water content in the sludge became 40% or less, heating of the pipe heater was stopped. After the completion of the fermentation treatment, the pipe heater was turned off while continuing the supply of compressed air to continue rotation, and the fermentation treatment tank 1 was left to cool. After cooling to approximately room temperature, the motor side of the fermentation treatment tank 1 was lifted by power, the outlet 8 was opened, and the treated sludge was taken out.
The treated sludge thus obtained had a water content of about 40% and had almost no odor, indicating that the fermentation treatment was successfully performed. Further, when the sludge after the fermentation treatment was analyzed, it was found that the sewage sludge had a quality that sufficiently satisfies the quality standard and the allowable content value of the sludge fermentation fertilizer.
[0022]
【The invention's effect】
In the aerobic fermentation treatment apparatus of the present invention, since the stirring blade has a special shape, the object to be treated inside is efficiently stirred, and particularly, the action of the movement of the object to the left and right and up and down. Therefore, the fermentation treatment of the object can be efficiently performed. In addition, the structure is relatively simple, and the installation and removal of the stirring blades can be easily performed, so that a highly durable device can be manufactured at a relatively low cost, and maintenance and inspection and repair of the device can be performed. Easy.
Furthermore, since the compressed air can be uniformly fed from the bottom of the aerobic fermentation treatment device without any deviation in the device, the fermentation treatment can be performed with high efficiency.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of an aerobic fermentation treatment apparatus of the present invention.
FIG. 2 is a front view of the stirring blade as viewed from a motor side in the fermentation treatment tank 1.
FIG. 3 is a development view, a front view, and a side view of the stirring blade 19;
FIG. 4 is a development view, a front view, and a side view of the stirring blade 20.
FIG. 5 is an explanatory view for attaching an air supply port 22 of the fermentation treatment tank 1.
[Explanation of symbols]
1. Fermentation tank 2. Inner wall 3. Outer wall 4. Insulation material5. Side wall 6. Side wall 7. Input port 8. Outlet 9. Suction port 10. Motor base11. Motor 12. Pipe heater13. Rotating shaft 14. Bearing 15. Bearing 16. Inlet 17. Automatic on-off valve 18. Air piping 19. Stirrer blade (2 steps)
19a. Plate-like portion 19b. The first inclined surface portion 19c. The second inclined surface portion 19d. Mounting part 20. Stirrer blade (single fold)
20a. Plate-like portion 20b. The second inclined surface portion 20c. Mounting part

Claims

In a horizontal cylindrical fermentation tank having a plurality of plate-shaped stirring blades mounted on a horizontal rotating shaft, an inlet for a processed material, an outlet for a processed processed material, and a tip of the blade in two stages. An aerobic fermentation treatment apparatus characterized in that two or more plate-shaped stirring blades each having an inclined surface portion bent into two sets are attached to a rotating shaft at an angle of 90 degrees with respect to each other.

The aerobic fermentation treatment apparatus according to claim 1, wherein the two stirring blades have bent surfaces in mutually opposite directions and have a positional relationship of 180 ° opposite to the rotation axis.

The aerobic fermentation treatment apparatus according to claim 1 or 2, wherein the two stirring blades are fixed to a rotating shaft with bolts and nuts at attachment portions thereof.

At the bottom of the horizontal cylindrical fermentation tank, a plurality of air inlets for compressed air are provided in the longitudinal direction, and air pipes connected to the compressor via automatic open / close valves are connected to these air inlets. The aerobic fermentation treatment apparatus according to any one of claims 1 to 3, wherein:

The aerobic fermentation treatment device according to claim 4, wherein the air supply port is attached to be inclined in a direction opposite to the rotation direction of the stirring blade.