JPS624499A - Anaerobic digestion method for organic waste liquid - Google Patents

Abstract

PURPOSE:To effectively execute anaerobic digestion reaction by allowing acid forming bacteria gorups and immobilized methane forming bacteria groups fixed to a high- polymer gel, etc. to mixedly exist in one tank and a naerobically treating org. waste liquid while bringing these groups into contact with the org. waste liquid. CONSTITUTION:The acid forming bacteria groups 6 and the immobilized methane forming bacteria groups 3 fixed to the high-polymer gel or porous inorg. carrier are made to mixedly exist in one fermentation tank 1 and the org. waste water is anaerobically treated while these bacteria groups are brought into contact with said liquid to convert the org. materials to gaseous methane and carbon dioxide. Namely, the bacteria can be maintained in the fermentation tank while the physiological activity is maintained by immobilizing and using the methane forming bacteria groups contribut ing to the methane formatino reaction which is the rate-determining step in the anaero bic digestion. The treatment of the waste org. liquid is thus efficiently executed and the amt. at which SS occurring in the bacteria flow together with the treated liquid to the outside of the system is decreased. Contribution is made to the improvement of the quality of the treated water as well. Since the holding of the bacteria is easy, the method is usable for the treatment of waste liquid having a low concn. of org. materials.

Description

【発明の詳細な説明】 ３、特許請求の範囲 産業上少且且分立 本発明は、有機性廃液を一つの槽内で嫌気的に消化する
嫌気性消化方法に関する。Detailed Description of the Invention 3. Claims Industrially Small and Separate The present invention relates to an anaerobic digestion method for anaerobically digesting organic waste liquid in one tank.

従来公技亜 従来、余剰汚泥やし尿等の有機性廃液は嫌気性消化法に
より処理されてきた。この方法は、副生産物のメタンガ
スを動力源として使用しうろこと、消化汚泥は良好な有
機質肥料として使用しうろこと等の利点を有している。BACKGROUND OF THE INVENTION Conventionally, organic waste liquids such as surplus sludge and human waste have been treated by anaerobic digestion. This method has advantages such as the use of methane gas as a by-product as a power source, and the use of digested sludge as a good organic fertilizer.

ところで、嫌気性消化のメカニズムとしては、主として
二つの反応によることが知られている。即ち、まず、廃
液中の有機物が酸生成菌群の作用により低分子化して酢
酸、酪酸等の揮発性脂肪酸となる酸生成反応と、これら
生成した脂肪酸がメタン生成菌群によりメタンガスに転
換される反応である。通常、嫌気性消化は両方の菌群を
同一槽内に混在させ、３０〜５０日といった長い期間を
かけて処理する方式がとられている。By the way, it is known that the mechanism of anaerobic digestion is mainly based on two reactions. That is, first, there is an acid production reaction in which the organic matter in the waste liquid is reduced to a low molecular weight by the action of acid-producing bacteria and becomes volatile fatty acids such as acetic acid and butyric acid, and then these produced fatty acids are converted into methane gas by the methanogenic bacteria. It is a reaction. Normally, anaerobic digestion involves mixing both groups of bacteria in the same tank and processing over a long period of 30 to 50 days.

く１　しよ゛と　る口　占 しかしながら、前記のように２つの反応を並行複反応と
してバランスよく進行させるため、消化日数が長いこと
、過負荷の運転に対する処置が必要であること及び処理
能力が小さいという欠点を有している。特に、脂肪酸か
らメタンガスに分解するメタン生成反応は、酸生成反応
に比較して大変遅く、嫌気性消化の律速段階となってお
り、消化日数が長くなる要因である。これに対処するた
め・発酵槽の後段に沈澱槽を設け、処理水と菌体を多く
含む汚泥とに分離して、汚泥を発酵槽に返送することに
より発酵槽内の菌群、特にメタン生成菌群の生理活性を
高めかつ維持している。However, as mentioned above, in order to allow the two reactions to proceed in a well-balanced manner as parallel multiple reactions, it takes a long time for digestion, it is necessary to take measures against overloaded operation, and the processing capacity is limited. It has the disadvantage of being small. In particular, the methane production reaction, in which fatty acids are decomposed into methane gas, is much slower than the acid production reaction, and is the rate-limiting step in anaerobic digestion, which is a factor in prolonging the number of days required for digestion. To deal with this, a sedimentation tank is installed after the fermenter to separate the treated water and sludge containing a large number of bacterial cells, and the sludge is returned to the fermenter. It increases and maintains the physiological activity of bacterial groups.

しかし、回収した菌群を発酵槽内に返送するため、発酵
槽容積を大きくしなければならず、消化日数の短縮、経
費の節減にあまり寄与していないのが現状である。よっ
て、メタン生成菌群の系外への流出を防止し、酸生成菌
群と共存させ、かつ生理活性を維持することが望まれて
いる。However, in order to return the collected bacteria to the fermenter, the volume of the fermenter must be increased, which does not contribute much to shortening the number of days required for digestion or reducing costs. Therefore, it is desired to prevent methane-producing bacteria from flowing out of the system, allow them to coexist with acid-producing bacteria, and maintain physiological activity.

従って、本発明は、前記の従来技術の欠点を解消し、発
酵槽内のメタン生成菌群を保持し、嫌気性消化反応を効
率よく行う有機性廃液の嫌気性消化方法を提供すること
を目的とする。Therefore, it is an object of the present invention to provide a method for anaerobic digestion of organic waste liquid, which eliminates the drawbacks of the prior art described above, retains the methane-producing bacteria group in the fermenter, and efficiently performs the anaerobic digestion reaction. shall be.

口　占　　゛　るための　　　び 本発明は、有機性廃液を並行複反応方式による嫌気性消
化する場合、反応に関与する二つの菌体群である酸生成
菌群及びメタン生成菌群のうち、増殖が遅いメタン生成
菌群を固定化することによって高い生理活性及び高濃度
で保持し、系外へ流出を防止することによって前記の問
題点を解決したものである。In order to clarify the present invention, when an organic waste liquid is anaerobically digested using a parallel multiple reaction system, among the two bacterial groups involved in the reaction, the acid-producing bacteria group and the methane-producing bacteria group, the growth The above-mentioned problems are solved by immobilizing slow methanogenic bacteria, retaining them at high physiological activity and concentration, and preventing them from leaking out of the system.

即ち、本発明方法は、酸生成菌群と高分子ゲル又は多孔
質無機担体に固定した固定化メタン生成菌群とを一つの
槽内に混在させ、これらと有機性廃液とを接触させなが
ら嫌気的に処理して、有機物をメタンガス及び炭酸ガス
に転換することを特徴とする。That is, in the method of the present invention, a group of acid-producing bacteria and a group of immobilized methane-producing bacteria immobilized on a polymer gel or a porous inorganic carrier are mixed in one tank, and the organic waste liquid is brought into contact with the acid-producing bacteria while being anaerobically heated. It is characterized by converting organic matter into methane gas and carbon dioxide gas.

メタン生成菌群の固定化には、ポリアクリルアミド、ア
ルギン酸カルシウム、カラギーナン、メトキシエチレン
グリコールメタクリレート、ポリエチレングリコールジ
メタクリレート、ポリエチレングリコールジアクリレー
ト、ポリプロピレングリコールジアクリレート等の高分
子ゲル、又は多孔性ガラス等の多孔性無機担体を固定化
材として使用することができる。For immobilization of methanogens, polymer gels such as polyacrylamide, calcium alginate, carrageenan, methoxyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate, or porous materials such as porous glass are used. Inorganic carriers can be used as immobilization materials.

固定化方法としては、担体結合法、包括固定法等、任意
の公知方法を使用することができる。As the immobilization method, any known method such as carrier binding method, entrapping immobilization method, etc. can be used.

本発明方法において、更に、酸生成菌は、浮遊状態の菌
体を長時間かけて圧密した粒径１〜２１１１の粒状フロ
ック、高分子ゲルに包括法若しくは担体結合法により固
定したもの、多孔性無機担体の内部若しくは外部に固定
したもの、板状、波板状、繊維状等の表面積の広い充填
材に付着“固定させたものでもよい。In the method of the present invention, the acid-producing bacteria may further include granular flocs with a particle size of 1 to 2111 obtained by compacting suspended bacterial cells over a long period of time, granular flocs with a particle size of 1 to 2,111 mm, which are obtained by compacting suspended bacterial cells over a long period of time; It may be fixed to the inside or outside of an inorganic carrier, or it may be attached to a filler with a wide surface area such as a plate, a corrugated plate, or a fiber.

次に、図面に基づいて本発明を詳述する。Next, the present invention will be explained in detail based on the drawings.

第１図及び第２図は、それぞれ本発明の実施態様を示す
フローシートである。1 and 2 are flow sheets showing embodiments of the present invention, respectively.

第１図において、発酵原料である有機性廃液は必要に応
じて破砕又は発酵成分の抽出、加水分解等の前処理を行
った後に、発酵槽ｌ内へ供給される。発酵槽１内には、
浮遊状態の酸生成菌群６と固定化メタン生成菌群３が混
在する。発酵槽１内に供給された発酵原料は、嫌気条件
下でガス攪拌用プロワ４によって送られるガスにより形
成した流動床によりこれらの菌群と接触する。接触時間
は０．３〜１５日間とし、発酵槽１内の温度は５０〜６
０℃、３４〜３７℃又は３３℃以下、ｐＨは６．７〜８
．０であるのが最適である。In FIG. 1, organic waste liquid, which is a raw material for fermentation, is supplied into a fermentation tank 1 after being subjected to pretreatments such as crushing, extraction of fermentation components, and hydrolysis as required. Inside fermenter 1,
Acid-producing bacteria group 6 in a floating state and immobilized methane-producing bacteria group 3 coexist. The fermentation raw material supplied into the fermenter 1 comes into contact with these bacterial groups through a fluidized bed formed by gas sent by the gas stirring blower 4 under anaerobic conditions. The contact time is 0.3 to 15 days, and the temperature in fermenter 1 is 50 to 6.
0°C, 34-37°C or below 33°C, pH 6.7-8
．． Optimally, it is 0.

発酵原料中の有機成分は、酸生成菌群の作用により低分
子化され、酢酸や酪酸等の揮発性脂肪酸に分解される。The organic components in the fermented raw materials are reduced in molecular weight by the action of acid-producing bacteria and decomposed into volatile fatty acids such as acetic acid and butyric acid.

また、有機成分の低分子化の過程で並行して発生する水
素ガス、炭酸ガス等のガスはガスホルダ２に貯留される
。更に、分解された揮発性脂肪酸は固定化メタン生成菌
内に取り込まれ、メタン生成菌によりメタンガスと炭酸
ガスとに転換される。発生したガスはガスホルダ２に貯
留される。Further, gases such as hydrogen gas and carbon dioxide gas generated in parallel during the process of reducing the organic component to low molecular weight are stored in the gas holder 2. Furthermore, the decomposed volatile fatty acids are taken into the immobilized methanogens and converted into methane gas and carbon dioxide gas by the methanogens. The generated gas is stored in the gas holder 2.

発酵槽１内で発生したガスの一部は、ガス攪拌用ブロワ
４へ送られる。A part of the gas generated in the fermenter 1 is sent to the gas stirring blower 4.

処理水は、固定化メタン生成菌と分離されて、系外に排
出され、固定化メタン生成菌は活性を維持したまま、発
酵槽に棲息することができる。The treated water is separated from the immobilized methanogens and discharged outside the system, and the immobilized methanogens can live in the fermenter while maintaining their activity.

第２図においては、攪拌機５によって流動状態を形成し
、有機性廃液を酸生成菌６及び固定化メタン生成菌３と
接触させる。In FIG. 2, a fluidized state is created by the stirrer 5, and the organic waste liquid is brought into contact with the acid-producing bacteria 6 and the immobilized methanogens 3.

去施奥 次に、実施例に基づいて本発明を詳述するが、本発明は
これに限定されるものではない。EXAMPLES Next, the present invention will be described in detail based on Examples, but the present invention is not limited thereto.

実施例 発酵原料として、酵母エキス、ペプトン及び肉エキスを
主成分とするＢＯＤ１２７ＱＯ曙／Ｉ！、Ｃ０Ｄ−５４
００■／Ｉ！の合成液を用い、第２図に示したフローシ
ートにより処理した。Example BOD127QO Akebono/I! whose main ingredients are yeast extract, peptone and meat extract as fermentation raw materials. , C0D-54
00■/I! The process was carried out according to the flow sheet shown in FIG. 2 using the synthetic solution.

発酵槽１内には、充分馴養された浮遊状態の酸生成菌群
とポリアクリルアミドゲルで包括固定した後、よく馴養
したメタン生成菌群とを混在させた。また、発酵槽１内
を嫌気状態に保持し、発酵原料と菌群とを充分接触させ
るために攪拌羽根を利用して機械攪拌した。発酵温度３
６℃、発酵原料の滞留時間８日、ｐＨ６，８〜７．２の
条件を保持した。In the fermenter 1, a group of acid-producing bacteria that had been sufficiently acclimated in a suspended state was mixed with a group of methanogenic bacteria that had been sufficiently acclimatized after being comprehensively fixed with polyacrylamide gel. Further, the inside of the fermenter 1 was maintained in an anaerobic state, and mechanical stirring was performed using a stirring blade in order to bring the fermentation raw material into sufficient contact with the bacterial group. Fermentation temperature 3
The conditions were maintained at 6°C, residence time of the fermented raw material for 8 days, and pH 6.8 to 7.2.

上記の条件下で実験した結果を下記の表に示す。The results of experiments conducted under the above conditions are shown in the table below.

なお、比較のため、酸生成菌群及びメタン生成菌群共に
浮遊状態で混在させる従来法により同条件で実験を行っ
た結果も表に併記した。For comparison, the results of an experiment conducted under the same conditions using a conventional method in which acid-producing bacteria and methane-producing bacteria were mixed in a suspended state are also listed in the table.

表に示した結果から明らかなとおり、本発明によれば、
菌体量を示す処理水中のＳＳは、メタン生成菌が固定さ
れているため、従来法に比較して著しく少ない。このよ
うに、本発明によれば、反応律速であるメタン生成菌が
保持され、また、処理水中のＳＳが少ないので、後段の
処理が容易となる。As is clear from the results shown in the table, according to the present invention,
SS in the treated water, which indicates the amount of bacterial cells, is significantly lower than in conventional methods because the methane-producing bacteria are fixed. As described above, according to the present invention, the methane-producing bacteria that are rate-limiting for the reaction are retained, and since there is little SS in the treated water, subsequent treatments are facilitated.

発１Ｒと匠果 本発明によれば、嫌気性消化における律速段階であるメ
タン生成反応に関与するメタン生成菌群を固定化して用
いることによって、発酵槽内に生理活性を維持したまま
保持することができる。従って、有機性廃液の処理を効
率よ〈実施することができ、また、菌体に起因するＳＳ
が処理水と共に系外に流出する量が減少し、処理水質の
向上にも寄与できる。更に、菌体保持が容易なことから
、有機物濃度の低い廃液の処理にも適用可能となる。According to the present invention, by immobilizing and using a group of methanogenic bacteria involved in the methanogenic reaction, which is the rate-limiting step in anaerobic digestion, it is possible to maintain physiological activity in the fermenter. Can be done. Therefore, organic waste liquid can be treated efficiently, and SS caused by bacterial cells can be treated efficiently.
This reduces the amount of water that flows out of the system together with the treated water, which can also contribute to improving the quality of the treated water. Furthermore, since bacterial cells can be easily retained, it can also be applied to the treatment of waste liquid with a low concentration of organic matter.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、本発明方法の一実施態様を示すフローシート
、第２図は、本発明方法の別の実施態様を示すフローシ
ートである。 工・・・発酵槽、２・・・ガスホルダ、３・・・固定化
メタン生成菌、４・・・ブロワ、５・・・攪拌機、６・
・・酸生成凹FIG. 1 is a flow sheet showing one embodiment of the method of the present invention, and FIG. 2 is a flow sheet showing another embodiment of the method of the present invention. Engineering: fermentation tank, 2: gas holder, 3: immobilized methane-producing bacteria, 4: blower, 5: stirrer, 6:
・・Acid generation concavity

Claims (2)

【特許請求の範囲】[Claims] （１）酸生成菌群と高分子ゲル又は多孔質無機担体に固
定した固定化メタン生成菌群とを一つの槽内に混在させ
、これらと有機性廃液とを接触させながら嫌気的に処理
して、有機物をメタンガス及び炭酸ガスに転換すること
を特徴とする有機性廃液の嫌気性消化方法。(1) Acid-producing bacteria and immobilized methane-producing bacteria fixed on a polymer gel or porous inorganic carrier are mixed in one tank, and the organic waste liquid is brought into contact with the acid-producing bacteria and treated anaerobically. A method for anaerobic digestion of organic waste liquid, characterized by converting organic matter into methane gas and carbon dioxide gas. （２）酸生成菌群をその汚泥自体を圧密して得られる粒
状フロックとして、又は高分子ゲル若しくは多孔質無機
担体に固定して使用する特許請求の範囲第１項記載の嫌
気性消化方法。(2) The anaerobic digestion method according to claim 1, wherein the acid-producing bacteria are used as granular flocs obtained by compacting the sludge itself, or fixed on a polymer gel or porous inorganic carrier.