JP2004243204A - Digestion treatment method for organic waste - Google Patents
Digestion treatment method for organic waste Download PDFInfo
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- JP2004243204A JP2004243204A JP2003034907A JP2003034907A JP2004243204A JP 2004243204 A JP2004243204 A JP 2004243204A JP 2003034907 A JP2003034907 A JP 2003034907A JP 2003034907 A JP2003034907 A JP 2003034907A JP 2004243204 A JP2004243204 A JP 2004243204A
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- organic waste
- anaerobic digestion
- anaerobic
- mordenite zeolite
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
- Y02A40/20—Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/40—Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse
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- Treatment Of Sludge (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Fertilizers (AREA)
- Processing Of Solid Wastes (AREA)
- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
Abstract
Description
【0001】
【発明の属する技術分野】
本発明は、有機性廃棄物、例えば家庭、スーパーマーケット、コンビニエンスストアーや食品工場等から排出される食品廃棄物、家庭の浄化槽・工場等の廃水処理設備・下水処理場等から排出される有機性汚泥、し尿、家畜排泄物、有機性排水等の有機性廃棄物の処理方法及び該方法を実施するための装置に関する。
【0002】
【従来の技術】
従来より、有機性廃棄物を消化処理するに当たり、粒子状あるいはスラッジ状の有機性廃棄物にウッドチップ、小枝、乾燥鶏糞ペレットなどの固形の副資材を混合し、水分含量80%程度で嫌気性消化を進める方法が知られているが(特許文献1)、この消化方法では有機物濃度が高くなるため、嫌気性消化工程で発生するアンモニアにより消化反応が阻害を受け、メタンが効率よく生産できないという難点があった。
【0003】
また、下水などのアンモニア含有汚水を高度に浄化する技術として、アンモニア吸着ゼオライト系鉱物の利用が提案されているが(特許文献2)、本提案は汚水の窒素除去に関するものであり、嫌気性消化に関するものでない。
【0004】
また、家畜などの糞尿から固形肥料を作成する方法としては、嫌気性消化した糞尿の消化液に水分吸収剤としてゼオライトを混合し、ペースト状となった混合物を乾燥・造粒することにより固形肥料とすることが提案されている(特許文献3)が、本提案も嫌気性消化の効率化効果を教示するものではない。
【0005】
【特許文献1】特開平11−306463号公報
【特許文献2】特開平9−314183号公報
【特許文献3】特開2002−29871号公報
【0006】
【発明が解決しようとする課題】
本発明は、上記従来技術の実情に鑑みなされたものであって、有機性廃棄物の処理方法において、有機廃棄物中の有機物を迅速に高い分解率で分解・消化処理することができると共にメタンや肥料を効率的に製造することができる、工業的に有利な有機廃棄物の処理方法および装置を提供することを目的とする。
【0007】
【発明を解決するための手段】
本発明者は、前記課題を解決すべく鋭意研究を重ねた結果、本発明を完成するに至った。
即ち、本発明によれば、以下の発明が提供される。
(1)有機性廃棄物を嫌気性消化する方法であって、モルデナイト系ゼオライトの存在下で嫌気性消化処理することを特徴とする有機性廃棄物の処理方法。
(2)有機性廃棄物の嫌気性消化処理方法であって、(I)有機性廃棄物とモルデナイト系ゼオライトを嫌気性消化槽に供給する工程、(II)供給された有機性廃棄物とモルデナイト系ゼオライトとの混合物を、嫌気性消化汚泥の存在下で嫌気性消化処理することを特徴とする上記(1)に記載の有機性廃棄物の処理方法。
(3)(II)の工程で得られるメタンを含有する気相部を燃料とすることを特徴とする上記(2)に記載の有機性廃棄物の処理方法。
(4)(II)の工程で得られる消化処理残渣を直接又は固液分離し肥料及び/又は肥料の原料として利用することを特徴とする上記(2)又は(3)に記載の有機性廃棄物の処理方法。
(5)処理残渣にアンモニアが吸着されたモルデナイト系ゼオライトが含有されていることを特徴とする上記(4)に記載の有機性廃棄物の処理方法。
(6)有機性廃棄物の嫌気性消化処理装置であって、有機性廃棄物とモルデナイト系ゼオライトを嫌気性消化槽に供給する装置を備えたことを特徴とする有機性廃棄物の嫌気性消化処理装置。
(7)有機性廃棄物の嫌気性消化処理装置であって、有機性廃棄物とモルデナイト系ゼオライトを嫌気性消化槽に供給する装置と、供給された混合物を嫌気性消化槽内で消化処理する装置を備えたことを特徴とする上記(6)に記載の有機性廃棄物の処理方法。
【0008】
【発明の実施の形態】
本発明の最大の特徴は、アンモニアによる微生物の消化反応の阻害、メタン生成効率の低下を克服し、かつ更なる処理残渣の肥料への有効利用化を促進するために、有機性廃棄物にモルデナイト系ゼオライトを添加混合し嫌気性消化処理を効率化した点にある。
【0009】
すなわち、従来の嫌気性消化処理において、有機性廃棄物中の窒素成分含量が高いとアンモニア濃度が高くなり、メタン生成阻害、メタン生成反応の停止やメタン生成速度の低下などの運転の不安定さの主な原因となっていたが、本発明方法では予め有機性廃棄物を消化処理するに当たり、嫌気性消化種汚泥と共にモルデナイト系ゼオライトを混合させたことから、モルデナイト系ゼオライトにより余剰のアンモニアが吸着され無害化されるため、嫌気性消化処理工程での有機廃棄物からのメタン及び二酸化炭素への変換反応が効率よく行われる。
【0010】
本発明方法においては、上記のように、嫌気性消化処理工程での有機性廃棄物からのメタン及び二酸化炭素への変換反応が効率よく進行する理由は現時点では定かではないが、有機性廃棄物を嫌気性消化汚泥と共にモルデナイト系ゼオライトを混合し嫌気性消化処理すると、嫌気性消化の過程で原料有機廃棄物中から生成するアンモニアをモルデナイト系ゼオライトが吸着し、アンモニアによるメタン生成反応への阻害が抑制され、さらにモルデナイト表面の特性がメタン生成微生物にとって繁殖しやすい環境となり、メタン生成微生物にとって最適な条件が作り出されるので、嫌気性消化工程における有機性廃棄物からのメタン及び二酸化炭素への変換反応が効率よく進むものと推定される。
【0011】
本発明の処理対象となる有機性廃棄物とは、一般家庭、レストラン、ホテル、食品工場、スーパーマーケットおよびコンビニエンスストアー等からの食品廃棄物。食品工場・浄化槽・下水処理場等で廃水処理時に発生する、初沈汚泥と呼ばれるタンパク質、炭水化物、脂質、繊維などの有機物と水の混合物、余剰汚泥と呼ばれる廃水浄化の際に増殖した微生物そのもの、食品工場・浄化槽・下水処理場等で廃水処理後排出される初沈汚泥と余剰汚泥の混合物である廃水処理汚泥一般。し尿、畜産排泄物、古紙類、剪定枝等植物性廃棄物や農産廃棄物が含まれる他、嫌気性消化した後に排出される消化汚泥など有機性廃棄物一般が包含される。
【0012】
本明細書で用いる、モルデナイト系ゼオライトとは、ゼオライトの一種で、一般に結晶(結晶構造MOR)中に空洞を数多くもつ多孔質物質であり、その化学組成は、ケイ酸塩のケイ素の一部がアルミニウムに置換された縮合酸塩の形をとり、代表的な組成は、下記一般式(1)で示される。
【化1】
(Ca, K2, Na2)[AlSi5O12]2・7H2O (1)
このモルデナイト系ゼオライトは、他のソーダライト系、ホーランダイト系、フィリプサイト系、チャバザイト系のゼオライトとは異なり、アンモニア吸着性を示すと共に、メタン生成微生物の繁殖を著しく促進し、メタン生産性に優れたものである。
このようなモルデナイト系ゼオライトとしては、例えばギスモンディン、モルデナイト、ユガワライト、エリオナイトなどを挙げることができるが、メタン生産性の点ではモルデナイトが好ましい。
このモルデナイトには天然のモルデナイトと合成モルデナイトが知られているが、本発明においてはいずれも使用できる。また、モルデナイト中のイオンを他の金属イオンにイオン交換したものも利用できる。
【0013】
本発明方法で好ましく採用される嫌気性消化処理方法の一例を以下に示す。
まず処理対象となる有機性廃棄物を破砕し、嫌気性消化種汚泥とモルデナイト系ゼオライトと混合する。この混合物の水分含量が60〜99.9%、好ましくは75〜90%の乾式、または90〜95%の湿式に調整し、10〜100℃好ましくは30〜35℃の中温発酵かまたは50〜70℃の高温発酵で嫌気性消化処理させ、メタンを発生させる。モルデナイト系ゼオライトの添加量は、0.1〜50重量%好ましくは2〜20重量%である。
【0014】
本発明において、処理対象有機性廃棄物、モルデナイト系ゼオライトおよび嫌気性消化種汚泥を混合させる方法は特に制限されず、処理対象有機廃棄物を破砕後モルデナイト系ゼオライトおよび嫌気性消化種汚泥と混合しても、処理対象有機物と嫌気性消化種汚泥が嫌気性消化槽内で混合された後、モルデナイト系ゼオライトを添加混合しても構わない。何れの方法においても、モルデナイト系ゼオライトが処理対象有機廃棄物および嫌気性消化種汚泥と均一に混合されれば、嫌気性消化槽内に於いてモルデナイト系ゼオライトによりアンモニアが吸着されて、効率よく嫌気性消化反応が進む。
【0015】
嫌気性消化種汚泥としては、例えば、酸発酵性微生物やメタン発酵性微生物を含有する下水汚泥の嫌気性消化に使用される通常の嫌気性消化汚泥や、既存の嫌気性消化汚泥を好気性分解産物に馴致培養したもの使用することができる。
なお、酸発酵性微生物とは、嫌気性消化において有機酸等を生成する微生物を意味し、Bacteroides sp.、Clostridium sp.、Bacillus sp.、Lactobacillus sp.等があげられる。また、メタン発酵性微生物とは、嫌気性消化においてメタンを生成する微生物を意味し、Methanosarcina sp.、Methanosaeta sp.、Methanogeum sp.等があげられる。両者とも従来よく知られているものである。
【0016】
前記のようにして、有機性廃棄物をモルデナイト系ゼオライトと共に嫌気性条件で微生物分解処理すると、嫌気性消化過程において生成する余剰のアンモニアがモルデナイト系ゼオライトによって吸着除去され、従来のアンモニアによるメタン生成阻害が防止される。従って、本発明方法では、嫌気性消化処理が効率よく進む。
【0017】
嫌気性消化処理時に発生するメタンは、ボイラー燃料、消化ガス発電、マイクロガスタービンや水素への改質後燃料電池の燃料として利用することが出来る。
【0018】
本発明方法では、嫌気性消化後の消化残渣はモルデナイト系ゼオライトを含み、このモルデナイト系ゼオライトはアンモニアを吸着しているので、コンポスト等の肥料や土壌改良材の原料として利用した場合、アンモニアが直ちに流出しないことや水分含量が低いという利点がある。従って、この残渣は、そのまま及び/又は固液分離後そのまま液体肥料や固形肥料として利用及び/又は肥料・土壌改良材の原料として利用すること可能である。
【0019】
次に、本発明方法を好ましく実施するための処理装置を、図面を参照しながら詳述する。
【0020】
図1において、1は有機性廃棄物貯留タンク、2は有機性廃棄物配管、3は嫌気性消化槽、4はモルデナイト系ゼオライト貯留タンク、5はモルデナイト系ゼオライト配管、6は消化ガス配管、7は消化ガス貯留タンク、8は嫌気性処理物配管、9は固液分離装置、10は処理液相部配管、11は処理液相部貯留タンク、12は処理固相部配管、13は処理固相部貯留タンクを各示す。
【0021】
図1の装置において、有機性廃棄物貯留タンク1より有機性廃棄物配管2を通って、原料がメタンを生じさせる嫌気性消化槽3に供給される。モルデナイト系ゼオライト貯留タンク4からモルデナイト系ゼオライト配管5を通って、モルデナイト系ゼオライトが嫌気性消化槽3に供給される。嫌気性消化槽3では、有機性廃棄物とモルデナイト系ゼオライトと嫌気性消化汚泥が混合・撹拌され、嫌気性消化が促進される。嫌気性消化槽3では、酸生成微生物やメタン生成微生物の働きで、有機性廃棄物がメタン、二酸化炭素、アンモニアなどに分解処理される。この時、嫌気性消化槽3にはモルデナイト系ゼオライトが添加されているので、遊離のアンモニア濃度が低く保たれ、メタン生成反応が阻害されない。
【0022】
また、嫌気性消化槽3内で発生したメタンを含む消化ガスは消化ガス配管6を通って消化ガス貯留タンク7に貯留される。この場合の消化ガスは、通常CH4:50〜100モル%、CO2:0〜50モル%、H2:0〜10モル%を含有する。
【0023】
嫌気性消化が進んだ処理物は、嫌気性処理物配管8を通って固液分離装置9に移送される。固液分離装置9では、嫌気性消化処理物が固液分離され、液相部は処理液相部配管10を通って処理液相部貯留タンク11に蓄えられる。固相部は、処理固相部配管12を通って、処理固相部貯留タンク13に蓄えられる。前記固液分離装置9は、濾過器や遠心分離機、沈降槽等からなる。
【0024】
処理固相部は肥料成分であるアンモニアがモルデナイト系ゼオライトに吸着されているので、土壌改良剤や有機肥料の原料として質が高い。処理液相部は、アンモニアがモルデナイト系ゼオライトに吸着されて固相部に多く移行しているので、アンモニア濃度が低く廃液のアンモニア除去処理が容易となる。
【0025】
【実施例】
以下、本発明を実施例により更に詳細に説明する。
【0026】
実施例1
50 ml容量のガラス瓶に、消化汚泥を40 ml、アンモニアを4500 mg N/l、モルデナイト系ゼオライト(天然モルデナイト(0.5〜1.5 mm規格)、株式会社イズカ製)を5%重量加えた。ゴム栓で密閉後内部のガスを窒素で置換してガラス瓶内を嫌気性にした。シリンジで消化ガスの発生量を測定しながら、35℃で2週間培養した。消化ガス中のメタン濃度は、ガスクロで測定した。嫌気性消化液中のアンモニア濃度は、イオンクロマトで測定した。
【0027】
比較例1
モルデナイト系ゼオライトを添加しない以外は実施例1に同様な処理を行い、消化ガス中のメタン濃度は、ガスクロで測定した。
【0028】
[実施例1と比較例1の実験結果及びその考察]
消化ガスの発生量は、モルデナイト系ゼオライトを添加しない比較例1では、226 mlであったが、実施例1のモルデナイト系ゼオライトを5%重量加えたガラス瓶からは600 ml発生した。
また、消化ガス中のメタン濃度は、モルデナイト系ゼオライトを添加しない比較例1では、46 %であったが、実施例1のモルデナイト系ゼオライトを5%重量加えたガラス瓶の方は 62 %であった。
【0029】
また、消化液中のアンモニア濃度は、モルデナイト系ゼオライトを添加しない比較例1では、3154 mg N/lであったが、実施例1のモルデナイト系ゼオライトを5%重量加えたガラス瓶からは2405 mg N/lであった。
【0030】
これらの実験結果から、本発明で用いるモルデナイト系ゼオライトにはアンモニアを吸着し、アンモニアのメタン発酵への阻害を抑制する働きがあることがわかる。
【0031】
【発明の効果】
本発明は前記構成からなるので、有機性廃棄物が嫌気性消化される際に、メタン生成の阻害物質であるアンモニアがモルデナイト系ゼオライトに吸着除去され、そのことにより嫌気性消化がスムーズに進み、またモルデナイト表面の特性がメタン生成微生物にとって繁殖しやすい環境となり、メタン生成微生物にとって最適な条件が作り出されるので、嫌気性消化工程における有機性廃棄物からのメタン及び二酸化炭素への変換反応が効率よく進む。また、本法によれば、最終的に発生する残滓(処理された固相部)にはモルデナイト系ゼオライトに吸着されたアンモニアが含有され、土壌改良剤や有機肥料の原料として質が高く、また処理液相部のアンモニア濃度が低く、廃液のアンモニア除去処理が容易になるといった、数多くの利点を有するものである。
【図面の簡単な説明】
【図1】本発明に係る有機性廃棄物の嫌気性消化処理装置の説明図である。
【符号の説明】
1. 有機性廃棄物貯留タンク
2. 有機性廃棄物配管
3. 嫌気性消化槽
4. モルデナイト系ゼオライト貯留タンク
5. モルデナイト系ゼオライト配管
6. 消化ガス配管
7. 消化ガス貯留タンク
8. 嫌気性処理物配管
9. 固液分離装置
10.処理液相部配管
11.処理液相部貯留タンク
12.処理固相部配管
13.処理固相部貯留タンク[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to organic waste, for example, food waste discharged from households, supermarkets, convenience stores, food factories, etc., and organic sludge discharged from wastewater treatment facilities, sewage treatment plants, etc., such as domestic septic tanks and factories. The present invention relates to a method for treating organic waste such as human waste, animal excrement, and organic wastewater, and an apparatus for implementing the method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in digesting organic wastes, solid auxiliary materials such as wood chips, twigs, dried chicken dung pellets, etc. are mixed with particulate or sludge-like organic wastes, and anaerobic at a water content of about 80%. Although a method of promoting digestion is known (Patent Document 1), the digestion reaction is inhibited by ammonia generated in an anaerobic digestion process due to an increase in the concentration of organic substances, and methane cannot be efficiently produced. There were drawbacks.
[0003]
In addition, as a technology for highly purifying ammonia-containing wastewater such as sewage, the use of an ammonia-adsorbed zeolite-based mineral has been proposed (Patent Document 2). However, this proposal relates to nitrogen removal of wastewater, and is anaerobic digestion. Not about.
[0004]
In addition, as a method of producing solid fertilizer from manure of livestock and the like, a solid fertilizer is prepared by mixing zeolite as a water absorbent with a digestive juice of anaerobic digested manure and drying and granulating the paste-like mixture. (Patent Document 3), but this proposal does not teach the effect of improving the efficiency of anaerobic digestion.
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No. 11-306463 [Patent Document 2] Japanese Patent Application Laid-Open No. 9-314183 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-29871
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned prior art, and in a method for treating organic waste, it is possible to quickly decompose and digest organic substances in organic waste at a high decomposition rate and to remove methane. It is an object of the present invention to provide an industrially advantageous organic waste treatment method and apparatus capable of efficiently producing fertilizer and fertilizer.
[0007]
[Means for Solving the Invention]
The present inventors have conducted intensive studies to solve the above problems, and as a result, completed the present invention.
That is, according to the present invention, the following inventions are provided.
(1) A method for anaerobic digestion of organic waste, wherein the anaerobic digestion treatment is performed in the presence of a mordenite zeolite.
(2) An anaerobic digestion treatment method of an organic waste, comprising: (I) a step of supplying an organic waste and a mordenite zeolite to an anaerobic digestion tank; (II) a step of supplying the supplied organic waste and a mordenite The method for treating organic waste according to the above (1), wherein the mixture with the zeolite is subjected to anaerobic digestion treatment in the presence of anaerobic digestion sludge.
(3) The method for treating organic waste according to (2), wherein the methane-containing gas phase obtained in the step (II) is used as a fuel.
(4) The organic waste according to (2) or (3), wherein the digestion treatment residue obtained in the step (II) is directly or solid-liquid separated and used as a fertilizer and / or a raw material for the fertilizer. How to handle things.
(5) The method for treating organic waste as described in (4) above, wherein the treatment residue contains a mordenite zeolite in which ammonia is adsorbed.
(6) An anaerobic digestion treatment apparatus for organic waste, comprising an apparatus for supplying organic waste and mordenite zeolite to an anaerobic digestion tank. Processing equipment.
(7) An apparatus for anaerobic digestion of organic waste, which supplies organic waste and mordenite zeolite to the anaerobic digestion tank, and digests the supplied mixture in the anaerobic digestion tank. The method for treating organic waste according to the above (6), further comprising an apparatus.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The most important feature of the present invention is that mordenite is added to organic waste in order to overcome the inhibition of microbial digestion by ammonia, to reduce the efficiency of methane production, and to promote the effective use of further processing residues in fertilizers. The point is that anaerobic digestion treatment is made more efficient by adding and mixing a zeolite.
[0009]
That is, in the conventional anaerobic digestion treatment, if the nitrogen content in the organic waste is high, the ammonia concentration becomes high, and the instability of operation such as inhibition of methane production, cessation of methane production reaction and reduction of methane production rate According to the method of the present invention, in the process of digesting the organic waste in advance, the mordenite zeolite was mixed with the anaerobic digestive sludge, so that excess ammonia was adsorbed by the mordenite zeolite. Therefore, the conversion reaction from organic waste to methane and carbon dioxide in the anaerobic digestion process is performed efficiently.
[0010]
In the method of the present invention, as described above, the reason why the conversion reaction from organic waste to methane and carbon dioxide efficiently proceeds in the anaerobic digestion treatment step is not clear at present, but the organic waste Is mixed with anaerobic digestion sludge and anaerobic digestion treatment, the mordenite zeolite adsorbs ammonia generated from raw organic waste in the process of anaerobic digestion, and the methane formation reaction by ammonia is inhibited. The conversion of organic waste to methane and carbon dioxide in the anaerobic digestion process is controlled because the characteristics of the mordenite surface are reduced and the mordenite surface becomes easy to proliferate for methanogenic microorganisms, creating optimal conditions for methanogenic microorganisms. Is estimated to proceed efficiently.
[0011]
The organic waste to be treated in the present invention is food waste from households, restaurants, hotels, food factories, supermarkets, convenience stores, and the like. Mixtures of organic matter and water such as proteins, carbohydrates, lipids, and fibers called primary sediment sludge generated during wastewater treatment in food factories, septic tanks, sewage treatment plants, etc., and microorganisms that have grown during wastewater purification called surplus sludge, Wastewater treatment sludge, which is a mixture of primary sludge and excess sludge discharged after wastewater treatment in food factories, septic tanks, sewage treatment plants, etc. It includes plant waste and agricultural waste such as night soil, livestock excrement, waste paper, pruned branches, and general organic waste such as digested sludge discharged after anaerobic digestion.
[0012]
As used herein, a mordenite zeolite is a type of zeolite, which is generally a porous substance having a large number of cavities in a crystal (crystal structure MOR). In the form of a condensed acid salt substituted by aluminum, a typical composition is represented by the following general formula (1).
Embedded image
(Ca, K 2, Na 2 ) [AlSi 5 O 12] 2 · 7H 2 O (1)
Unlike other sodalite, hollandite, filipsite, and chabazite zeolite, this mordenite zeolite exhibits ammonia-adsorbing properties, significantly promotes the growth of methanogenic microorganisms, and has excellent methane productivity. It is a thing.
Examples of such a mordenite zeolite include gismondin, mordenite, yugawarite, and erionite, and mordenite is preferable in terms of methane productivity.
As the mordenite, natural mordenite and synthetic mordenite are known, and both can be used in the present invention. Further, those obtained by ion-exchanging ions in mordenite with other metal ions can also be used.
[0013]
An example of the anaerobic digestion method preferably employed in the method of the present invention is shown below.
First, the organic waste to be treated is crushed and mixed with the anaerobic digestive seed sludge and the mordenite zeolite. The water content of this mixture is adjusted to 60-99.9%, preferably 75-90% dry, or 90-95% wet, and medium-temperature fermentation at 10-100 ° C, preferably 30-35 ° C, or 50-90 ° C. Anaerobic digestion is performed by high-temperature fermentation at 70 ° C to generate methane. The addition amount of the mordenite zeolite is 0.1 to 50% by weight, preferably 2 to 20% by weight.
[0014]
In the present invention, the method of mixing the organic waste to be treated, the mordenite zeolite and the anaerobic digestive seed sludge is not particularly limited, and the garbage is mixed with the mordenite zeolite and the anaerobic digestive seed sludge after crushing the organic waste to be treated. However, after the organic matter to be treated and the anaerobic digestive seed sludge are mixed in the anaerobic digestion tank, the mordenite zeolite may be added and mixed. In any method, if the mordenite zeolite is uniformly mixed with the organic waste to be treated and the anaerobic digestive seed sludge, ammonia is adsorbed by the mordenite zeolite in the anaerobic digestion tank and efficiently anaerobic. The sexual digestion reaction proceeds.
[0015]
As anaerobic digestive seed sludge, for example, the usual anaerobic digestion sludge used for anaerobic digestion of sewage sludge containing acid-fermenting microorganisms and methane-fermenting microorganisms, and aerobic digestion of existing anaerobic digestion sludge Cultured products can be used.
The acid-fermenting microorganism refers to a microorganism that produces an organic acid or the like in anaerobic digestion, and Bacteroides sp. Clostridium sp. Bacillus sp. Lactobacillus sp. And the like. Further, the methane fermentation microorganisms, means a microorganism that produce methane in anaerobic digestion, Methanosarcina sp. , Methanosaeta sp. , Metanogeum sp. And the like. Both are well known in the past.
[0016]
As described above, when the organic waste is subjected to the biodegradation treatment under anaerobic conditions together with the mordenite zeolite, excess ammonia generated in the anaerobic digestion process is adsorbed and removed by the mordenite zeolite, and methane production is inhibited by conventional ammonia. Is prevented. Therefore, in the method of the present invention, the anaerobic digestion process proceeds efficiently.
[0017]
Methane generated during anaerobic digestion can be used as fuel for boiler fuel, digestion gas power generation, micro gas turbines and fuel cells after reforming to hydrogen.
[0018]
In the method of the present invention, the digestion residue after anaerobic digestion contains mordenite zeolite, and since this mordenite zeolite adsorbs ammonia, when used as a raw material for fertilizers such as compost or soil improvement material, ammonia is immediately It has the advantage that it does not flow out and has a low water content. Therefore, this residue can be used as it is and / or after solid-liquid separation as it is as a liquid fertilizer or a solid fertilizer and / or as a raw material of a fertilizer / soil improving material.
[0019]
Next, a processing apparatus for preferably executing the method of the present invention will be described in detail with reference to the drawings.
[0020]
In FIG. 1, 1 is an organic waste storage tank, 2 is an organic waste pipe, 3 is an anaerobic digestion tank, 4 is a mordenite zeolite storage tank, 5 is a mordenite zeolite pipe, 6 is a digestion gas pipe, 7 Is a digestion gas storage tank, 8 is an anaerobic treated pipe, 9 is a solid-liquid separator, 10 is a treated liquid phase pipe, 11 is a treated liquid phase storage tank, 12 is a treated solid phase pipe, and 13 is a treated solid pipe. Each phase storage tank is shown.
[0021]
In the apparatus of FIG. 1, raw materials are supplied from an organic
[0022]
The digestion gas containing methane generated in the
[0023]
The processed material that has undergone anaerobic digestion is transferred to the solid-
[0024]
The treated solid phase has a high quality as a soil conditioner or a raw material of an organic fertilizer because ammonia as a fertilizer component is adsorbed on the mordenite zeolite. In the treatment liquid phase, ammonia is adsorbed by the mordenite zeolite and is largely transferred to the solid phase, so that the ammonia concentration is low and the ammonia removal treatment of the waste liquid becomes easy.
[0025]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples.
[0026]
Example 1
To a glass bottle having a capacity of 50 ml, 40 ml of digested sludge, 4500 mg N / l of ammonia, and 5% by weight of mordenite zeolite (natural mordenite (0.5-1.5 mm standard), manufactured by Izka Corporation) were added. . After sealing with a rubber stopper, the inside gas was replaced with nitrogen to make the inside of the glass bottle anaerobic. The cells were cultured at 35 ° C. for 2 weeks while measuring the amount of digested gas generated with a syringe. The methane concentration in the digested gas was measured by gas chromatography. The ammonia concentration in the anaerobic digestive fluid was measured by ion chromatography.
[0027]
Comparative Example 1
The same treatment as in Example 1 was performed except that the mordenite zeolite was not added, and the methane concentration in the digested gas was measured by gas chromatography.
[0028]
[Experimental results of Example 1 and Comparative example 1 and consideration thereof]
The amount of digestion gas generated was 226 ml in Comparative Example 1 in which the mordenite zeolite was not added, but 600 ml was generated from the glass bottle of Example 1 to which 5% by weight of the mordenite zeolite was added.
The methane concentration in the digestion gas was 46% in Comparative Example 1 in which the mordenite zeolite was not added, but was 62% in the glass bottle of Example 1 in which 5% by weight of the mordenite zeolite was added. .
[0029]
The ammonia concentration in the digestive juice was 3154 mg N / l in Comparative Example 1 to which no mordenite zeolite was added, but 2405 mg N from the glass bottle of Example 1 to which 5% by weight of mordenite zeolite was added. / L.
[0030]
These experimental results show that the mordenite zeolite used in the present invention has a function of adsorbing ammonia and suppressing the inhibition of ammonia on methane fermentation.
[0031]
【The invention's effect】
Since the present invention has the above configuration, when organic waste is anaerobically digested, ammonia which is a methane production inhibitor is adsorbed and removed by the mordenite zeolite, whereby anaerobic digestion proceeds smoothly, In addition, the characteristics of the mordenite surface provide an environment in which methane-producing microorganisms can easily proliferate, creating optimal conditions for methane-producing microorganisms. move on. According to the present method, the finally generated residue (the treated solid phase) contains ammonia adsorbed on the mordenite zeolite, and has high quality as a raw material for soil conditioners and organic fertilizers. It has a number of advantages, such as a low ammonia concentration in the treatment liquid phase portion, which facilitates the ammonia removal treatment of the waste liquid.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an apparatus for anaerobic digestion of organic waste according to the present invention.
[Explanation of symbols]
1. Organic
Claims (7)
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006150216A (en) * | 2004-11-29 | 2006-06-15 | National Institute Of Advanced Industrial & Technology | Method for treating organic waste |
JP2009213978A (en) * | 2008-03-07 | 2009-09-24 | Kyowa Exeo Corp | Process for wet methane fermentation of organic waste with high fat and oil content |
CN102584366A (en) * | 2012-02-17 | 2012-07-18 | 新疆山川秀丽生物有限公司 | Microbial organic fertilizer as well as preparation method and application thereof |
CN104858215A (en) * | 2015-05-27 | 2015-08-26 | 北京洁绿科技发展有限公司 | Innocent treatment method of dead livestock |
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2003
- 2003-02-13 JP JP2003034907A patent/JP2004243204A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006150216A (en) * | 2004-11-29 | 2006-06-15 | National Institute Of Advanced Industrial & Technology | Method for treating organic waste |
JP2009213978A (en) * | 2008-03-07 | 2009-09-24 | Kyowa Exeo Corp | Process for wet methane fermentation of organic waste with high fat and oil content |
CN102584366A (en) * | 2012-02-17 | 2012-07-18 | 新疆山川秀丽生物有限公司 | Microbial organic fertilizer as well as preparation method and application thereof |
CN104858215A (en) * | 2015-05-27 | 2015-08-26 | 北京洁绿科技发展有限公司 | Innocent treatment method of dead livestock |
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