JP2019141778A - Anaerobic digestion tank startup method and anaerobic digestion system - Google Patents

Anaerobic digestion tank startup method and anaerobic digestion system Download PDF

Info

Publication number
JP2019141778A
JP2019141778A JP2018028159A JP2018028159A JP2019141778A JP 2019141778 A JP2019141778 A JP 2019141778A JP 2018028159 A JP2018028159 A JP 2018028159A JP 2018028159 A JP2018028159 A JP 2018028159A JP 2019141778 A JP2019141778 A JP 2019141778A
Authority
JP
Japan
Prior art keywords
sludge
digester
concentration
digestion tank
digestion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2018028159A
Other languages
Japanese (ja)
Other versions
JP2019141778A5 (en
JP6954853B2 (en
Inventor
真也 樋口
Shinya Higuchi
真也 樋口
昌次郎 渡邊
Shojiro Watanabe
昌次郎 渡邊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Swing Corp
Original Assignee
Swing Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=67770769&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=JP2019141778(A) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Swing Corp filed Critical Swing Corp
Priority to JP2018028159A priority Critical patent/JP6954853B2/en
Publication of JP2019141778A publication Critical patent/JP2019141778A/en
Publication of JP2019141778A5 publication Critical patent/JP2019141778A5/ja
Priority to JP2021159789A priority patent/JP7228653B2/en
Application granted granted Critical
Publication of JP6954853B2 publication Critical patent/JP6954853B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00Technologies for the production of fuel of non-fossil origin
    • Y02E50/30Fuel from waste, e.g. synthetic alcohol or diesel

Landscapes

  • Treatment Of Sludge (AREA)
  • Processing Of Solid Wastes (AREA)
  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)

Abstract

To provide an anaerobic digestion tank startup method and an anaerobic digestion system that provide an easy start-up method for digestive tanks, as well as ensure ease of work related to startup and smooth startup.SOLUTION: An anaerobic digestion tank startup method includes: charging water and/or seed sludge into a digestion tank 2 where a concentrating mechanism 1 is arranged in the previous stage of a treatment flow; concentrating the seed sludge and raw sludge, to obtain concentrated sludge; charging the concentrated sludge into a digestion tank; and increasing the amount of the concentrated sludge charged into the digestion tank 2.SELECTED DRAWING: Figure 4

Description

本発明は、嫌気性消化槽の立ち上げ方法及び嫌気性消化システムに関する。   The present invention relates to a method for starting an anaerobic digester and an anaerobic digestion system.

嫌気性消化処理は下水処理場の水処理設備などで発生する下水汚泥や有機性排水を嫌気性微生物の代謝作用により分解し汚泥や排水を減容化するとともに分解過程で発生するメタンガスを回収し再利用資源として活用できる処理であり従来から広く利用されている。   Anaerobic digestion treatment decomposes sewage sludge and organic wastewater generated at water treatment facilities at sewage treatment plants by metabolic action of anaerobic microorganisms, reduces sludge and wastewater, and collects methane gas generated in the decomposition process. This process can be used as a reusable resource and has been widely used.

嫌気性消化処理の分解過程は嫌気性微生物である酸生成菌とメタン生成細菌の働きにより汚泥中の有機分をガス化することで行われ、酸性発酵期、酸性減退期およびアルカリ性発酵期の分解過程を経て行われる。そのため、消化槽内に投入される下水汚泥や有機性排水の量に見合った嫌気性微生物を消化槽内に保持することが重要であるとともに、酸生成菌に比べ、pH、有機酸濃度および温度変動に敏感で増殖速度も遅いメタン生成細菌の生育に適した最適条件を保持し有機分の分解過程のバランスを保つことが重要である。   The decomposition process of anaerobic digestion is performed by gasifying organic components in sludge by the action of acid-producing bacteria and methanogenic bacteria, which are anaerobic microorganisms, and decomposes during the acidic fermentation period, acidic decline period, and alkaline fermentation period. It goes through the process. For this reason, it is important to maintain anaerobic microorganisms in the digestion tank that are commensurate with the amount of sewage sludge and organic wastewater that is introduced into the digestion tank, and the pH, organic acid concentration and temperature compared to acid-producing bacteria. It is important to maintain the optimal conditions suitable for the growth of methanogenic bacteria that are sensitive to fluctuations and slow in growth rate, and to keep the balance of the organic degradation process.

嫌気性消化を行う消化槽の立ち上げには、まずタンク内に水を満たし、配管系統の気密試験を行う。その後、可能であれば消化槽内に嫌気性微生物を含む汚泥(種汚泥)を投入し、消化処理対象となる原汚泥を投入する。原汚泥の投入量を徐々に増加させ、嫌気性微生物を消化槽内で十分に増殖させて馴致させる。通常は、種汚泥を投入してから50〜60日で定常運転が可能であることが知られている(例えば、非特許文献1参照)。   To start up a digester that performs anaerobic digestion, first fill the tank with water and conduct an airtight test on the piping system. Thereafter, if possible, sludge containing anaerobic microorganisms (seed sludge) is introduced into the digestion tank, and raw sludge to be digested is introduced. Gradually increase the input amount of raw sludge and allow the anaerobic microorganisms to grow sufficiently in the digestion tank. Normally, it is known that steady operation is possible in 50 to 60 days after the seed sludge is introduced (see, for example, Non-Patent Document 1).

原汚泥投入開始前に種汚泥を当該消化槽内へ投入することは、消化処理に必要な活性化された嫌気性微生物を立ち上げ当初より消化槽内へ入れることになるため、種汚泥投入量が多いほど馴致にかかる時間が短縮できる。しかしながら、消化槽内を事前に種汚泥のみで満たすことは必要量確保の観点から難しい場合が多く、消化槽容量の1/2以下にとどまる場合が一般的には多い。   Inputting seed sludge into the digestion tank before starting the input of raw sludge introduces activated anaerobic microorganisms necessary for digestion into the digestion tank from the start, so the amount of seed sludge input The more it is, the shorter the time it takes to adapt. However, it is often difficult to fill the digestion tank only with seed sludge in advance from the viewpoint of securing the necessary amount, and in many cases it is generally less than 1/2 of the digestion tank capacity.

消化能力は消化槽中の嫌気性微生物の保持量すなわち消化槽中の汚泥濃度に比例する。原汚泥の投入開始当初は消化槽中の汚泥濃度が定常運転時より低く消化能力が低いため投入原汚泥量を抑える必要があり、一般的には消化汚泥中の固形物量の5%以下である。原汚泥投入を継続することで消化槽中の汚泥濃度も徐々に上昇し、原汚泥の投入量増加が可能となる。   The digestibility is proportional to the amount of anaerobic microorganisms retained in the digester, that is, the sludge concentration in the digester. At the beginning of raw sludge input, the sludge concentration in the digestion tank is lower than in normal operation and the digestion capacity is low, so it is necessary to suppress the amount of raw sludge input. Generally, it is 5% or less of the solid content in the digested sludge. . By continuing the input of raw sludge, the sludge concentration in the digestion tank gradually increases, and the input amount of raw sludge can be increased.

嫌気性消化は消化汚泥中の嫌気性微生物の保持量とともにアルカリ分の保持量も重要な因子となる。消化汚泥中のアルカリ分は一般的に総アルカリ度を指標としており、嫌気性消化における有機物分解過程で生成される有機酸等による過度なpH低下を抑制する緩衝作用によりメタン生成細菌の生育に適した最適pHの保持が可能となる。   In the anaerobic digestion, the retained amount of the anaerobic microorganisms in the digested sludge and the retained amount of the alkali are important factors. Alkaline content in digested sludge is generally based on total alkalinity, and is suitable for the growth of methanogenic bacteria due to its buffer action that suppresses excessive pH drop caused by organic acids generated during the decomposition of organic matter in anaerobic digestion. The optimum pH can be maintained.

投入開始当初は消化汚泥中の総アルカリ度が定常運転より低く、pHの緩衝能力が低いため、原汚泥投入量増加による有機酸蓄積によりpH低下が発生し易い状況であり、消化槽中の汚泥濃度とともにアルカリ分の濃度を上昇させることで原汚泥の投入量増加が可能となる。   At the beginning of charging, the total alkalinity in the digested sludge is lower than that in steady operation and the pH buffering capacity is low, so the pH is likely to decrease due to organic acid accumulation due to an increase in the input amount of raw sludge. It is possible to increase the input amount of raw sludge by increasing the concentration of alkali as well as the concentration.

近年、消化槽の立ち上げ期間を短縮する試みがなされている。特許第4819757号公報では、嫌気性消化槽に種汚泥を投入した後、消化槽中の汚泥の一部を抜き出し、抜き出した汚泥を脱水処理して脱水汚泥を得て、この脱水汚泥を消化槽に返送することが記載されている。これによれば、少量の種汚泥でも嫌気性消化システムを短時間で立ち上げることができると記載されている。   In recent years, attempts have been made to shorten the digestion tank startup period. In Japanese Patent No. 4819757, after introducing seed sludge into an anaerobic digester, a part of the sludge in the digester is extracted, and the extracted sludge is dehydrated to obtain dehydrated sludge. To be returned to. According to this, it is described that anaerobic digestion system can be started up in a short time even with a small amount of seed sludge.

特許第4819757号公報Japanese Patent No. 4819757

公益社団法人日本下水道協会、「下水道維持管理指針 実務編−2014年版」、平成26年9月12日発行、p.832−834Japan Sewerage Association, “Guidelines for Sewerage Maintenance and Management-2014 edition”, issued on September 12, 2014, p. 832-834

しかしながら、非特許文献1の方法では、消化槽の立ち上げ処理開始後、50〜60日程度の馴致期間が必要で、消化槽の立ち上げ期間全体としては半年〜1年となるため、非常に長期間を要する。一般に、消化槽の運用に必要な加温は、消化槽より発生するメタンガスをエネルギーとして行われているが、メタンガスの回収・利用が困難な立ち上げ期間中は、別途燃料が必要であるため費用もかかる。また、立ち上げ初期の馴致期間においては、消化槽内に満たされた水に少量の原汚泥が混合された脱水困難な汚泥濃度を有する排水が、槽外へ流出又は引き抜かれる。その間、引き抜かれた排水を水処理設備にて処理し、水処理設備で処理されて得られた汚泥を返送することになるが、水処理設備への負荷が消化槽の立ち上げ期間中に著しく上昇するという問題もある。よって立ち上げ期間は出来るだけ短期に行うことが望ましい。   However, in the method of Non-Patent Document 1, an acclimatization period of about 50 to 60 days is required after the start-up process of the digestion tank, and the entire start-up period of the digestion tank is half a year to one year. It takes a long time. In general, the heating required for digestion tank operation is performed using methane gas generated from the digestion tank as energy, but during the start-up period when it is difficult to recover and use methane gas, additional fuel is required. It also takes. Moreover, in the acclimatization period at the initial stage of start-up, wastewater having a sludge concentration that is difficult to dewater, in which a small amount of raw sludge is mixed with the water filled in the digestion tank, flows out or is drawn out of the tank. During that time, the drained wastewater is treated in the water treatment facility, and the sludge obtained by the treatment in the water treatment facility is returned. However, the load on the water treatment facility is significantly increased during the start-up period of the digester. There is also the problem of rising. Therefore, it is desirable that the start-up period be as short as possible.

特許文献1に記載された発明は、消化槽から引き抜かれた汚泥を、遠心脱水機、スクリュープレス脱水機、ロータリープレス脱水機などの汚泥処理手法の一つである汚泥脱水より水分含量85質量%以下の脱水汚泥にし、この脱水汚泥を消化槽に再投入することで、早期立ち上げを実現している。   The invention described in Patent Document 1 has a moisture content of 85% by mass from sludge dewatering that is one of sludge treatment methods such as centrifugal dehydrator, screw press dehydrator, rotary press dehydrator and the like. The following dewatered sludge is used, and this dewatered sludge is re-introduced into the digestion tank to achieve early start-up.

脱水汚泥とは一般的に、固形物として扱うことができる程度まで脱水された汚泥のことで、脱水ケーキともいう。通常含水率85%以下のものをいう。   The dehydrated sludge is generally sludge dehydrated to such an extent that it can be handled as a solid, and is also called a dehydrated cake. Usually, the water content is 85% or less.

しかしながら、特許文献1に記載されるような脱水汚泥を、ポンプや配管等を用いて消化槽へ圧送しようとすると、高い動力が必要となると共に配管又はポンプの詰まりが頻繁に生じる。即ち、特許文献1に記載される脱水汚泥の消化槽へのポンプによる配管圧送は現実には困難である。脱水汚泥を消化槽へ返送するためには、ベルトコンベヤ等の搬送機が別途必要となり、装置が大型化する。また、脱水汚泥を当該消化槽へ移送する為に別途設置した搬送機は、当該消化槽の立ち上げ時のみ使用可能であり、汎用性は乏しい。   However, when trying to pump dewatered sludge as described in Patent Document 1 to a digester using a pump, piping, or the like, high power is required and piping or pumps are frequently clogged. In other words, it is actually difficult to pump the dewatered sludge described in Patent Document 1 to the digestion tank using a pump. In order to return the dewatered sludge to the digestion tank, a conveyor such as a belt conveyor is required separately, which increases the size of the apparatus. In addition, a conveyor installed separately for transferring dewatered sludge to the digestion tank can be used only when the digestion tank is started up, and is not versatile.

現在稼働中の一般的な水処理設備は、消化設備と汚泥脱水設備が遠く離れた位置に配備されている場合が多い。脱水設備は汚泥脱水を行うための脱水機、脱水機から排出される脱水汚泥を搬送する搬送機、及び搬送された汚泥を貯留する為のホッパ等により構成されている。また、脱水設備は屋内に構成されることが多く、搬送機による汚泥移送の観点から1階高所又は中階以上に脱水機が設置されることが多い。更に作業環境への配慮の観点から、防臭対策として脱水機からホッパまでの搬送路をカバー等で閉塞空間とする場合もある。   In general water treatment facilities currently in operation, digestion facilities and sludge dewatering facilities are often deployed at remote locations. The dewatering equipment includes a dehydrator for performing sludge dewatering, a transporter for transporting the dewatered sludge discharged from the dewaterer, a hopper for storing the transported sludge, and the like. In addition, the dehydration equipment is often configured indoors, and from the viewpoint of sludge transfer by the transporter, the dehydrator is often installed on the first floor high place or the middle floor or higher. Further, from the viewpoint of consideration of the work environment, there is a case where the conveying path from the dehydrator to the hopper is closed with a cover or the like as a deodorizing measure.

そのため、特許文献1に記載の技術を、既存の水処理設備に応用すると、脱水設備から遠く離れた消化設備への汚泥の搬送のために、搬送車を配備するか、大型の搬送設備を仮設しなければならず、搬送費用もかかる。また、建屋内高所より屋外の当該消化槽へ移送する必要があり、閉塞された搬送路から脱水汚泥を取り出す必要があるため、現実には困難である。   Therefore, when the technology described in Patent Document 1 is applied to an existing water treatment facility, a transport vehicle is installed or a large transport facility is temporarily installed for transporting sludge to a digestion facility far from the dehydration facility. It also has to be transported. Moreover, since it is necessary to transfer from the high place in a building to the said digesting tank of the outdoors, and it is necessary to take out dehydrated sludge from the obstructed conveyance path, it is difficult in reality.

更に、特許文献1に記載された発明では、消化槽から抜き出した汚泥を脱水処理して汚泥中の多量の水分を排出させることで、水分とともに汚泥中のアルカリ分も失われる。脱水処理によりアルカリ分が失われた汚泥を消化槽へ返送することで固形分濃度(TS濃度)は上昇するが、アルカリ分は増加しない状況となる。嫌気性消化処理は消化汚泥のTS濃度に見合ったアルカリ分を保持することで、有機酸濃度が上昇してもアルカリ分の緩衝作用により消化反応に最適な中性付近のpHを保持することが可能であるが、TS濃度に対応したアルカリ分が不足する場合は消化反応に最適な中性付近のpH保持が難しくなる。   Furthermore, in the invention described in Patent Document 1, the sludge extracted from the digester is dehydrated to discharge a large amount of water in the sludge, so that the alkali content in the sludge is lost along with the water. By returning sludge from which alkali content has been lost by dehydration to the digestion tank, the solid content concentration (TS concentration) increases, but the alkali content does not increase. Anaerobic digestion treatment keeps the alkali content suitable for the TS concentration of the digested sludge, and even if the organic acid concentration rises, it can keep the pH near neutral optimum for digestion reaction by the buffering action of the alkali content. Although it is possible, when the alkali content corresponding to the TS concentration is insufficient, it is difficult to maintain a pH near neutral optimum for the digestion reaction.

更に、消化反応が不安定になり易い立ち上げ期間は有機酸が蓄積し易い傾向があり、TS濃度に見合ったアルカリ分を保持されていない場合はより消化反応に最適な中性付近のpH保持が難しくなる。脱水汚泥を混合させた上で安定した消化反応を進行させるには、消化槽へアルカリ剤を添加する必要が生じる場合がある。   Furthermore, organic acids tend to accumulate during the start-up period during which the digestion reaction is likely to be unstable. When the alkali content corresponding to the TS concentration is not maintained, the pH is maintained near neutrality, which is more optimal for the digestion reaction. Becomes difficult. In order to proceed a stable digestion reaction after mixing dewatered sludge, it may be necessary to add an alkaline agent to the digester.

アルカリ分の量はこれに対応する炭酸カルシウム(CaCo3)の濃度で表し、一般的にはpH4.8までの酸素消費量である総アルカリ度で測定される。汚泥中の総アルカリ度は汚泥濃度により異なり、TS濃度が2%程度で2500〜2700mg‐CaCO3/L程度、3%程度で3900〜4100mg‐CaCO3/L程度となる。 The amount of alkali is represented by the corresponding concentration of calcium carbonate (CaCo 3 ) and is generally measured by the total alkalinity, which is the oxygen consumption up to pH 4.8. The total alkalinity in the sludge varies depending on the sludge concentration. When the TS concentration is about 2%, it is about 2500 to 2700 mg-CaCO 3 / L, and about 3% is about 3900 to 4100 mg-CaCO 3 / L.

更に、特許文献1に記載された発明のように、嫌気性消化汚泥を含水率85%以下の脱水汚泥にするためには、有機性高分子凝集剤が用いられることが一般的であり、脱水の対象となる汚泥の性状により異なる。例えば、地方共同法人 日本下水道事業団、機械設備標準仕様書 平成28年度、平成28年6月1日発行、P.12−15、12−16、12−23、12−44(参考文献1)によれば、添加量は対象となる汚泥中に含まれる固形物量に対して概ね1.1〜2.1%が目標値とするのが一般的であるが、実施設においては脱水汚泥の目標含水率を達成させるために、2.0%以上の注入率とする場合も多く見られる。また、環境技術学会、月刊誌「環境技術」2004年8月号、研究論文「下水処理余剰汚泥の嫌気性消化に及ぼす高分子凝集剤の影響」、P.631〜638(参考文献2)の報告では、有機系高分子凝集剤の添加量が汚泥中に含まれる固形物量に対して1%以下では影響はないが、1%以上で消化阻害の懸念があり、2〜3%以上で消化阻害が発生すると記載されており、特許文献1に記載の技術でも同様の消化阻害を惹き起こす可能性がある。   Further, as in the invention described in Patent Document 1, an organic polymer flocculant is generally used to make anaerobic digested sludge into a dehydrated sludge having a water content of 85% or less. It depends on the properties of the sludge that is subject to For example, the Japan Sewage Works Association, a local joint corporation, machine equipment standard specifications issued in 2016, June 1, 2016, p. According to 12-15, 12-16, 12-23, 12-44 (reference document 1), the addition amount is approximately 1.1 to 2.1% with respect to the solid amount contained in the target sludge. Generally, the target value is used, but in order to achieve the target moisture content of the dewatered sludge, there are many cases where the injection rate is 2.0% or more. In addition, the Environmental Technology Society, monthly magazine “Environmental Technology” August 2004 issue, research paper “Effect of polymer flocculant on anaerobic digestion of surplus sludge from sewage treatment”, p. In the report of 631-638 (reference document 2), there is no influence when the amount of the organic polymer flocculant added is 1% or less with respect to the amount of solids contained in the sludge. Yes, it is described that digestion inhibition occurs at 2 to 3% or more, and the technique described in Patent Document 1 may cause similar digestion inhibition.

更に、脱水汚泥を消化槽に返送する場合、消化汚泥中へ脱水汚泥を分散させる必要がある。脱水汚泥は前述の通り固形物に近い性状となるため、そのまま当該消化槽に投入しても槽内で十分に再溶解されない懸念がある。   Furthermore, when returning dehydrated sludge to a digestion tank, it is necessary to disperse dehydrated sludge in digested sludge. Since dehydrated sludge has properties close to solids as described above, there is a concern that even if it is put into the digestion tank as it is, it will not be sufficiently re-dissolved in the tank.

更に、参考文献2によれば有機系高分子凝集剤による阻害は嫌気系消化細菌の活性阻害であると記載されており、再溶解されなければ局所的に有機系高分子凝集剤量が高くなり、機能しなくなる懸念がある。   Further, according to Reference 2, it is described that the inhibition by the organic polymer flocculant is an activity inhibition of anaerobic digestive bacteria, and the amount of the organic polymer flocculant locally increases unless re-dissolved. There is a concern that it will not function.

近年では汚泥処理容量の削減等を目的として嫌気性消化処理の原汚泥にあらかじめ有機系高分子凝集剤を添加し、濃縮させて消化させる方式が一般化してきており、更に立ち上げ時の有機系高分子凝集剤による消化阻害のリスクが大きくなる。   In recent years, for the purpose of reducing sludge treatment capacity, organic polymer flocculants are added in advance to anaerobic digestion raw sludge and concentrated to digest. The risk of digestion inhibition by the polymer flocculant increases.

更に近年の消化処理における消化槽においては、ガスの噴流により槽内汚泥を流動させるガス撹拌、及び大型の撹拌羽根を用いた低速撹拌等のケーキ上のものを破砕・分散することが難しい撹拌方式が主流となっており、脱水汚泥を当該消化槽に返送しても槽内で十分に再溶解されない懸念が高まるため、脱水汚泥を溶解又は破砕する設備が別途必要となる場合がある。   Furthermore, in the digestion tanks used in recent digestion treatments, it is difficult to crush and disperse the cake on the cake, such as gas stirring that causes the sludge in the tank to flow by gas jets and low speed stirring using large stirring blades. Since there is a growing concern that even if dehydrated sludge is returned to the digestion tank, it will not be sufficiently re-dissolved in the tank, a separate facility for dissolving or crushing dehydrated sludge may be required.

上記課題を鑑み、本発明は、消化槽の早期かつ安定的に立ち上げる方法を提供すると共に、立ち上げに関わる作業の簡便性及び円滑な立ち上げ性も併せ持つ嫌気性消化システムを提供する。   In view of the above-described problems, the present invention provides an anaerobic digestion system that provides a method for quickly and stably starting up a digester, and also has the convenience of work related to startup and smooth startup.

上記目的を達成するために、本発明者らが鋭意検討したところ、消化槽の前段に濃縮機構を配置し、濃縮機構において通常消化槽へ投入される汚泥より高い濃度へ濃縮処理された濃縮汚泥を消化槽へ投入することが有効な手段の1つであることを見いだした。   In order to achieve the above-mentioned purpose, the present inventors diligently studied, and, as a result, a concentrating mechanism was disposed in the previous stage of the digestion tank, and the concentrated sludge was concentrated to a higher concentration than the sludge charged into the normal digestion tank in the concentrating mechanism. It has been found that the introduction of the water into the digester is one of the effective means.

以上の知見を基礎として完成した本発明の一側面において、処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、種汚泥と原汚泥とを濃縮し、濃縮汚泥を得ることと、濃縮汚泥を消化槽に投入することと、消化槽への濃縮汚泥の投入量を増加させることとを含む嫌気性消化槽の立ち上げ方法が提供される。   In one aspect of the present invention completed on the basis of the above knowledge, water and / or seed sludge is introduced into a digestion tank in which a concentration mechanism is arranged in the previous stage of the treatment flow, and seed sludge and raw sludge are concentrated. There is provided a method for starting an anaerobic digester that includes obtaining concentrated sludge, introducing the concentrated sludge into the digester, and increasing the amount of the concentrated sludge charged into the digester.

本発明において「処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入する」工程は、一般的に行われる立ち上げ初期の手順であり、その詳細は特に限定されるものではない。即ち、「処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入する」工程には、消化槽に水又は種汚泥を単独又は両方投入した後に、消化槽内を嫌気状態とし、必要に応じて加温するような立ち上げ初期に当業者が適宜行い得る工程を包含するものである。   In the present invention, the process of “injecting water and / or seed sludge into a digestion tank in which a concentration mechanism is arranged in the previous stage of the treatment flow” is a generally performed initial procedure, and details thereof are particularly limited. It is not something. That is, in the process of “injecting water and / or seed sludge into a digestion tank in which a concentration mechanism is arranged in the previous stage of the processing flow”, after the water or seed sludge is introduced into the digestion tank alone or both, It includes a process that can be appropriately performed by those skilled in the art at the initial stage of start-up, in which an anaerobic state is established and heating is performed as necessary.

本発明における「濃縮機構」とは、汚泥処理手法の一つである低濃度の汚泥を固液分離によりTS濃度を数〜十数wt%程度まで高め、消化や脱水プロセスを効果的に機能させるための汚泥濃縮を行い、濃縮汚泥を排出する装置又は設備を指す。   The “concentration mechanism” in the present invention refers to one of sludge treatment techniques, by increasing the TS concentration to about several to tens of wt% by solid-liquid separation of sludge, and effectively allowing digestion and dehydration processes to function. It refers to an apparatus or facility that concentrates sludge and discharges concentrated sludge.

本方法によれば、消化汚泥のアルカリ分は有機物の分解過程で生成されるため、有機分が分解される前の原汚泥を濃縮することで消化槽中の汚泥が保持するアルカリ分を失わずに安定的かつ期間短縮を両立した立ち上げ方法を提供することができる。   According to this method, since the alkalinity of digested sludge is generated in the process of decomposing organic matter, the alkalinity retained by the sludge in the digestion tank is not lost by concentrating the raw sludge before the organic component is decomposed. It is possible to provide a start-up method that is both stable and shortened.

本発明は別の一側面において、処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、原汚泥を濃縮し、濃縮汚泥を得ることと、前記濃縮汚泥を前記消化槽に投入することと、前記消化槽内の汚泥の一部を引き抜いて引抜汚泥を得ることと、前記引抜汚泥の少なくとも一部を前記原汚泥とともに濃縮し、前記消化槽へ返送することとを含む嫌気性消化槽の立ち上げ方法が提供される。   According to another aspect of the present invention, water and / or seed sludge is introduced into a digestion tank in which a concentration mechanism is disposed in the front stage of the treatment flow, the raw sludge is concentrated to obtain the concentrated sludge, and the concentration Introducing sludge into the digestion tank, extracting a part of the sludge in the digestion tank to obtain a drawn sludge, concentrating at least a part of the drawn sludge together with the raw sludge, and returning to the digester An anaerobic digester start-up method is provided.

本方法によれば、消化槽からの引抜汚泥を消化槽へ返送することで、脱水汚泥のような低い含水率の汚泥を生成させるために多量に添加される凝集剤に由来する消化阻害の問題や、脱水汚泥を生成する過程で多量に失われるアルカリ分の問題や、配管閉塞等の問題を低減することができる。また、特別な脱水汚泥を消化槽内で溶解させるための溶解装置等も不要で、作業の簡便性及び円滑な立ち上げ性を両立した立ち上げ方法を提供することができる。   According to this method, the problem of digestion inhibition derived from the flocculant added in large quantities to produce sludge having a low water content such as dewatered sludge by returning the extracted sludge from the digester to the digester. In addition, it is possible to reduce problems such as alkali content lost in a large amount in the process of generating dewatered sludge and piping clogging. In addition, there is no need for a dissolving device for dissolving special dewatered sludge in the digestion tank, and it is possible to provide a start-up method that achieves both easy work and smooth start-up.

本発明は更に別の一側面において、処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、種汚泥と原汚泥とを濃縮し、濃縮汚泥を得ることと、前記濃縮汚泥を前記消化槽に投入することと、前記消化槽から汚泥の一部を引き抜いて引抜汚泥を得ることと、前記引抜汚泥の少なくとも一部を前記種汚泥及び前記原汚泥とともに濃縮し、前記消化槽へ返送することと、前記消化槽へ投入する濃縮汚泥の投入量を増加させることとを含む嫌気性消化槽の立ち上げ方法が提供される。   In another aspect of the present invention, water and / or seed sludge is introduced into a digestion tank in which a concentration mechanism is disposed in the front stage of the treatment flow, and seed sludge and raw sludge are concentrated to obtain concentrated sludge. Adding the concentrated sludge to the digestion tank, extracting a part of the sludge from the digestion tank to obtain a extracted sludge, and at least a part of the extracted sludge together with the seed sludge and the raw sludge. A method for starting an anaerobic digester is provided that includes concentrating and returning to the digester, and increasing the amount of concentrated sludge that is input to the digester.

本発明に係る嫌気性消化槽の立ち上げ方法は更に別の一実施態様において、消化槽に水及び/又は種汚泥を投入する際、前記種汚泥を投入する場合には、前記種汚泥を前記濃縮機構において濃縮処理した後に前記消化槽へ投入することを含む。   In yet another embodiment of the method for starting up the anaerobic digester according to the present invention, when water and / or seed sludge is introduced into the digester, the seed sludge is added when the seed sludge is introduced. Injecting the digestion tank after the concentration process in the concentration mechanism.

本発明に係る嫌気性消化槽の立ち上げ方法は更に別の一実施態様において、種汚泥として、既設の消化槽から発生する汚泥を用いることを含む。   In yet another embodiment, the method for starting an anaerobic digester according to the present invention includes using sludge generated from an existing digester as seed sludge.

本発明に係る嫌気性消化槽の立ち上げ方法は更に別の一実施態様において、濃縮機構に供給される汚泥の固形物量に対し、凝集剤を0.2〜1.5質量%添加して濃縮処理することを含む。   In yet another embodiment of the method for starting up the anaerobic digester according to the present invention, the flocculant is added in an amount of 0.2 to 1.5% by mass with respect to the solid amount of sludge supplied to the concentration mechanism and concentrated. Including processing.

本発明に係る嫌気性消化槽の立ち上げ方法は更に別の一実施態様において、消化槽に、汚泥濃度4〜12質量%の濃縮汚泥を供給することを含む。   In yet another embodiment, the method for starting up the anaerobic digester according to the present invention includes supplying concentrated sludge having a sludge concentration of 4 to 12% by mass to the digester.

本発明は更に別の一側面において、原汚泥を濃縮して濃縮汚泥を得る濃縮機構と、濃縮汚泥を嫌気性消化処理する消化槽と、消化槽と濃縮機構との間に配置され、消化槽から引き抜かれた引抜汚泥の一部を濃縮機構へ循環させる配管とを備える嫌気性消化システムが提供される。   In yet another aspect, the present invention is arranged between a concentration mechanism for concentrating raw sludge to obtain concentrated sludge, a digestion tank for anaerobically digesting the concentrated sludge, a digestion tank and a concentration mechanism, An anaerobic digestion system is provided that includes a pipe that circulates a portion of the extracted sludge extracted from the system to a concentration mechanism.

本発明に係る嫌気性消化システムは一実施態様において、種汚泥を濃縮機構へ供給する汚泥供給手段を更に備えることができる。当該消化槽と同一処理場に配置された稼働中又は廃止及び長期停止する予定又は行っている消化槽から種汚泥を供給できる場合は、既に連続して供給できる機能を備えているため汚泥供給手段は不要となる。   In one embodiment, the anaerobic digestion system according to the present invention may further include sludge supply means for supplying seed sludge to the concentration mechanism. When seed sludge can be supplied from a digester that is in operation, is abolished, and is scheduled to be stopped for a long time, or is operating for a long time, disposed in the same treatment plant as the digester, sludge supply means because it already has a function that can be supplied continuously Is no longer necessary.

本発明に係る嫌気性消化システムは別の一実施態様において、濃縮機構が、消化槽へ投入する汚泥の高濃度化を目的とした消化槽付帯の濃縮機構を含む嫌気性消化システムが提供される。   In another embodiment of the anaerobic digestion system according to the present invention, there is provided an anaerobic digestion system in which the concentration mechanism includes a concentration mechanism attached to the digestion tank for the purpose of increasing the concentration of sludge to be introduced into the digestion tank. .

本発明に係る嫌気性消化システムは更に別の一実施態様において、消化槽が、汚泥濃度1〜12質量%の汚泥を嫌気性消化処理して、0.5〜9質量%の消化汚泥を排出する消化槽である。消化槽の中でも濃縮機構が消化槽に付帯した消化槽である場合、汚泥濃度4〜12質量%、望ましくは6〜10質量%の高濃度な濃縮汚泥を投入し消化処理することが望ましい。本実施形態においてはこのような形態をなすものを高濃度消化槽と定義し、以降に表記する。   In yet another embodiment of the anaerobic digestion system according to the present invention, the digester performs anaerobic digestion of sludge having a sludge concentration of 1 to 12% by mass to discharge 0.5 to 9% by mass of digested sludge. It is a digester. In the case of a digester with a concentrating mechanism attached to the digester, it is desirable to perform digestion treatment by introducing a concentrated sludge having a high sludge concentration of 4 to 12% by mass, preferably 6 to 10% by mass. In the present embodiment, such a form is defined as a high-concentration digester and will be described hereinafter.

本発明によれば、消化槽の早期立ち上げ方法を提供すると共に、立ち上げに関わる作業の簡便性及び円滑な立ち上げ性も併せ持つ嫌気性消化システムが提供できる。   ADVANTAGE OF THE INVENTION According to this invention, while providing the digestive tank early startup method, the anaerobic digestion system which also has the simplicity of the operation | work regarding startup, and smooth startup property can be provided.

本発明の実施形態に係る嫌気性消化システムの適用に好適な水処理システムの例を示す概略図である。It is the schematic which shows the example of the water treatment system suitable for application of the anaerobic digestion system which concerns on embodiment of this invention. 本発明の実施形態に係る嫌気性消化システムの適用に好適な別の水処理システムの例を示す概略図である。It is the schematic which shows the example of another water treatment system suitable for application of the anaerobic digestion system which concerns on embodiment of this invention. 本発明の第1の実施の形態に係る嫌気性消化システムの一例を示す概略図である。It is the schematic which shows an example of the anaerobic digestion system which concerns on the 1st Embodiment of this invention. 本発明の第2の実施の形態に係る嫌気性消化システムの一例を示す概略図である。It is the schematic which shows an example of the anaerobic digestion system which concerns on the 2nd Embodiment of this invention. 本発明の第2の実施の形態の変形例に係る嫌気性消化システムの一例を示す概略図である。It is the schematic which shows an example of the anaerobic digestion system which concerns on the modification of the 2nd Embodiment of this invention. 立ち上げ期間に対する消化槽中の消化汚泥固形物濃度の変化のシミュレーション結果を表すグラフである。It is a graph showing the simulation result of the change of the digested sludge solid substance density | concentration in a digester with respect to a starting period. 立ち上げ期間に対する消化槽中の消化汚泥アルカリ量の変化を総アルカリ度で評価したシミュレーション結果を表すグラフである。It is a graph showing the simulation result which evaluated the change of the amount of digested sludge alkalis in a digestion tank with respect to a start-up period by total alkalinity. 立ち上げ期間に対する消化槽中の有機性高分子凝集剤濃度の変化のシミュレーション結果を表すグラフである。It is a graph showing the simulation result of the change of the organic polymer flocculent density | concentration in a digester with respect to a starting period.

以下、図面を参照しながら本発明の実施の形態について説明する。以下の図面の記載においては、同一又は類似の部分には同一又は類似の符号を付している。なお、以下に示す実施の形態はこの発明の技術的思想を具体化するための装置や方法を例示するものであって、この発明の技術的思想は、構成部品の構造、配置等を下記のものに特定するものではない。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is to describe the structure, arrangement, etc. of components as follows. It is not something specific.

<水処理システム>
本発明の実施の形態に係る嫌気性消化システムについて説明する前に、本嫌気性消化システムの適用に好適な水処理システムの例を図1及び図2に示すが、以下の例に限定されないことは勿論である。
<Water treatment system>
Before explaining the anaerobic digestion system according to the embodiment of the present invention, an example of a water treatment system suitable for application of the present anaerobic digestion system is shown in FIG. 1 and FIG. 2, but not limited to the following examples. Of course.

図1に示すように、本発明の実施の形態に係る水処理システムは、水処理場の汚水処理施設へ供給された汚水を原水として、この原水を固液分離する最初沈殿池20と、最初沈殿池20で除去されなかった有機性浮遊物と溶解性有機物を微生物の働きにより分解・安定化させる反応タンク30と、反応タンクで処理された活性汚泥を固液分離する最終沈殿池40と、反応タンク30及び最終沈殿池40で生じた余剰汚泥を機械濃縮する機械濃縮機構50と、最初沈殿池20の固液分離により生じた汚泥を重力濃縮する重力濃縮機構60と、機械濃縮機構50及び重力濃縮機構60により濃縮された汚泥又は未濃縮の汚泥を混合する混合槽70と、混合槽70から供給される汚泥をメタン発酵菌等の働きにより嫌気性条件下で消化させ減容化する消化槽90とを備える。   As shown in FIG. 1, a water treatment system according to an embodiment of the present invention uses a sewage supplied to a sewage treatment facility of a water treatment plant as a raw water, a first settling basin 20 for solid-liquid separation of the raw water, A reaction tank 30 that decomposes and stabilizes organic suspended solids and dissolved organic substances that have not been removed in the sedimentation basin 20 by the action of microorganisms, and a final sedimentation basin 40 that solid-liquid separates the activated sludge treated in the reaction tank, A mechanical concentration mechanism 50 for mechanically concentrating excess sludge generated in the reaction tank 30 and the final sedimentation basin 40, a gravity concentration mechanism 60 for gravity concentrating sludge generated by solid-liquid separation in the initial sedimentation basin 20, a mechanical concentration mechanism 50, and The mixing tank 70 for mixing the sludge concentrated by the gravity concentration mechanism 60 or the unconcentrated sludge and the sludge supplied from the mixing tank 70 are digested under anaerobic conditions by the action of methane fermentation bacteria and the like to reduce the volume. And a digester 90.

或いは、図2に示すように、消化槽90と混合槽70との間に機械濃縮機構80を更に備えていてもよい。   Alternatively, as shown in FIG. 2, a mechanical concentration mechanism 80 may be further provided between the digestion tank 90 and the mixing tank 70.

本発明の実施の形態に係る嫌気性処理システムは、処理フローの前段に濃縮機構が配置された消化槽90の立ち上げに際し、好適に実施することができるものである。例えば、図1に示すような、機械濃縮機構50及び重力濃縮機構60を消化槽90の前段に有するような水処理システムや、図2に示すような、機械濃縮機構50、重力濃縮機構60、機械濃縮機構80を消化槽90の前段に有するような水処理システム等に好適である。図1に示す水処理システムを以下に示す本発明の実施の形態に係る嫌気性消化システムに応用する場合は、機械濃縮機構50及び/又は重力濃縮機構60を、本実施形態に係る濃縮機構1として利用することができる。図2に示すような水処理システムを本発明の実施の形態に係る嫌気性消化システムに応用する場合には、機械濃縮機構50及び/又は重力濃縮機構60及び/又は機械濃縮機構80を、本実施形態に係る濃縮機構1として利用することができる。以下に本発明の第1、及び第2の実施の形態に係る嫌気性消化システムの詳細について説明する。   The anaerobic processing system according to the embodiment of the present invention can be suitably implemented when starting up the digester tank 90 in which the concentration mechanism is arranged in the previous stage of the processing flow. For example, as shown in FIG. 1, a water treatment system having a mechanical concentration mechanism 50 and a gravity concentration mechanism 60 in the front stage of the digestion tank 90, a mechanical concentration mechanism 50, a gravity concentration mechanism 60, as shown in FIG. It is suitable for a water treatment system or the like having a mechanical concentrating mechanism 80 in the front stage of the digestion tank 90. When the water treatment system shown in FIG. 1 is applied to the anaerobic digestion system according to the embodiment of the present invention described below, the mechanical concentration mechanism 50 and / or the gravity concentration mechanism 60 is replaced with the concentration mechanism 1 according to the present embodiment. Can be used as When the water treatment system as shown in FIG. 2 is applied to the anaerobic digestion system according to the embodiment of the present invention, the mechanical concentrating mechanism 50 and / or the gravity concentrating mechanism 60 and / or the mechanical concentrating mechanism 80 are installed in the present embodiment. It can utilize as the concentration mechanism 1 which concerns on embodiment. Details of the anaerobic digestion system according to the first and second embodiments of the present invention will be described below.

(第1の実施の形態)
本発明の第1の実施の形態に係る嫌気性処理システムは、図3に示すように、種汚泥と原汚泥とを濃縮して濃縮汚泥を得る濃縮機構1と、濃縮汚泥を嫌気性消化処理する消化槽2と、種汚泥を濃縮機構1へ供給する種汚泥供給手段5を備える。種汚泥の供給元は特に限定は無いが、望ましくは同一敷地内に設置された稼働中又は稼働中であったが将来停止予定の消化槽4等を用いることが好ましい。種汚泥供給手段5としては、配管、運搬機など、既設消化汚泥を運搬可能な手段であれば特に限定されない。
(First embodiment)
As shown in FIG. 3, the anaerobic treatment system according to the first embodiment of the present invention concentrates seed sludge and raw sludge to obtain concentrated sludge, and anaerobic digestion treatment of the concentrated sludge. And a seed sludge supply means 5 for supplying the seed sludge to the concentration mechanism 1. There is no particular limitation on the supply source of the seed sludge, but it is preferable to use the digester 4 or the like that is currently in operation or is in operation but is scheduled to be shut down in the future. The seed sludge supply means 5 is not particularly limited as long as it is a means capable of transporting existing digested sludge, such as a pipe and a transporter.

本発明に用いられる原汚泥としては、例えば、メタン発酵菌、水素発酵菌の嫌気性微生物が消化可能な有機分を含む汚泥であればよく、特に限定されない。例えば、下水処理場の水処理設備などで発生する下水汚泥、或いは食品工場、製紙工場、畜産場などで発生する排水又は屎尿などを含む有機性排水等が利用可能である。   The raw sludge used in the present invention is not particularly limited as long as it contains organic components that can be digested by anaerobic microorganisms such as methane-fermenting bacteria and hydrogen-fermenting bacteria. For example, sewage sludge generated in a water treatment facility of a sewage treatment plant, or organic waste water including waste water generated in a food factory, a paper mill, a livestock farm, or the like can be used.

原汚泥にバイオマスなどの生物由来の有機資源を混合させてもよい。具体的には、生ごみ、おから、焼酎粕などを原汚泥に混合することができる。   Biological organic resources such as biomass may be mixed with the raw sludge. Specifically, raw garbage, okara, shochu, etc. can be mixed with raw sludge.

濃縮機構1は、低濃度の汚泥を固液分離によりTS濃度数〜十数wt%程度まで高め、消化や脱水プロセスを効果的に機能させる濃縮を行う装置であればよく、特に限定されない。例えば、濃縮機構1は、重力濃縮、遠心濃縮、浮上濃縮、ベルトろ過濃縮、スクリーン濃縮等を行って、汚泥を濃縮処理する。濃縮機構1は、濃縮装置、造粒槽、薬品供給器を備えることができる。   The concentration mechanism 1 is not particularly limited as long as it is a device that increases the concentration of low-concentration sludge to a TS concentration of about several tens of wt% or more by solid-liquid separation and effectively functions the digestion and dehydration processes. For example, the concentration mechanism 1 performs gravity concentration, centrifugal concentration, levitation concentration, belt filtration concentration, screen concentration, and the like to concentrate sludge. The concentration mechanism 1 can include a concentration device, a granulation tank, and a chemical supply device.

汚泥を濃縮するに当たり、脱水性の良い汚泥に対しては、特段凝集剤等の薬品添加は不要であるが、濃縮性の悪い汚泥に対し、ポリ硫酸第二鉄、PAC、硫酸バンドなどの無機系凝集剤または有機性高分子凝集剤等を、単独又は組み合わせて添加してもよい。   When concentrating sludge, chemicals such as a special flocculant are not necessary for sludge with good dewaterability, but for sludge with poor condensability, inorganic substances such as polyferric sulfate, PAC, and sulfuric acid bands are used. A system flocculant or an organic polymer flocculant may be added alone or in combination.

以下に限定されるものではないが、濃縮機構1は、濃縮機構1に投入される汚泥の固形物濃度を、原汚泥のTS濃度以上12wt%以下、望ましくは4〜12wt%、更に望ましくは6〜10wt%に濃縮することが好ましい。   Although not limited to the following, the concentration mechanism 1 is configured so that the solid matter concentration of the sludge input to the concentration mechanism 1 is not less than the TS concentration of the raw sludge and not more than 12 wt%, preferably 4 to 12 wt%, more preferably 6 It is preferable to concentrate to -10 wt%.

図3に示すように濃縮機構1は、消化槽2に付帯して隣接するか、又は消化槽2と一体化して配置される図2に示す機械濃縮機構80の形態であることが好ましい。これにより、立ち上げに適した汚泥の濃縮が可能となるとともに濃縮機構1で濃縮された濃縮汚泥を消化槽2へ容易に移送できる。例えば、濃縮機構1は、消化槽2の上部に設置し、濃縮汚泥を重力により搬送するように構成されれば、濃縮汚泥の搬送のための手段は実質不要になる。   As shown in FIG. 3, the concentration mechanism 1 is preferably in the form of the mechanical concentration mechanism 80 shown in FIG. 2 that is attached to and adjacent to the digestion tank 2 or integrated with the digestion tank 2. As a result, it is possible to concentrate the sludge suitable for start-up and to easily transfer the concentrated sludge concentrated by the concentration mechanism 1 to the digestion tank 2. For example, if the concentration mechanism 1 is installed in the upper part of the digestion tank 2 and configured to convey the concentrated sludge by gravity, a means for conveying the concentrated sludge becomes substantially unnecessary.

濃縮機構1は、早期立ち上げの観点から、機械濃縮処理を行うための機械濃縮機構であることが好ましい。機械濃縮機構としては、例えば、ウェッジワイヤースクリーン、バースクリーンなどを備えた機器によるスクリーン濃縮を用いることが好ましい。   The concentration mechanism 1 is preferably a mechanical concentration mechanism for performing a mechanical concentration process from the viewpoint of early start-up. As the mechanical concentrating mechanism, for example, it is preferable to use screen concentrating by an apparatus equipped with a wedge wire screen, a bar screen, or the like.

消化槽2としては、特に限定されないが、例えば完全混合型消化槽を用いることができる。消化槽2は、槽内液の均質化や温度分布の均一化とともに、スカムの発生を防止するために、内部に撹拌設備が配置されている。消化槽2内では、嫌気性細菌の働きにより、汚泥中の有機物が揮発性有機酸及び低級アルコール類に加水分解された後、メタン発酵菌の作用により有機酸などの中間生成物がメタン、二酸化炭素、アンモニア等に分解される。   Although it does not specifically limit as the digester 2, For example, a complete mixing type digester can be used. The digestion tank 2 is provided with an agitation facility in order to homogenize the liquid in the tank and uniform the temperature distribution, and to prevent the occurrence of scum. In digester 2, organic substances in sludge are hydrolyzed to volatile organic acids and lower alcohols by the action of anaerobic bacteria, and then intermediate products such as organic acids are converted to methane, dioxide by the action of methane fermentation bacteria. Decomposed into carbon, ammonia, etc.

消化槽2としては、例えばTS濃度が1〜6wt%、典型的には2〜4wt%の一般的な下水汚泥の嫌気性消化処理の装置が用いられる。   As the digestion tank 2, for example, a general sewage sludge anaerobic digestion apparatus having a TS concentration of 1 to 6 wt%, typically 2 to 4 wt% is used.

更に消化槽2としては、消化槽へ投入する汚泥濃度を高濃度へ濃縮することで、汚泥を小容量で投入でき、小容量の消化槽2において少量の汚泥から多量の消化ガスを発生させる高濃度消化槽を含む。例えばTS濃度が4〜12wt%、望ましくは6〜10wt%の汚泥を嫌気性消化処理可能な装置が用いられる。   Furthermore, as the digester 2, the sludge concentration to be added to the digester is concentrated to a high concentration, so that the sludge can be introduced in a small volume, and a large amount of digestion gas is generated from a small amount of sludge in the small-capacity digester 2. Includes a concentration digester. For example, an apparatus capable of anaerobic digestion of sludge having a TS concentration of 4 to 12 wt%, desirably 6 to 10 wt% is used.

例えば、本発明者らの実験によれば、TS濃度6〜10wt%の汚泥を処理可能な消化槽2を高濃度消化槽とすることで、TS濃度2〜4wt%程度の汚泥を処理する従来の汚泥消化の消化槽よりも、消化槽2の容積を1/2〜1/8程度に縮小できるため、設置スペースを低減でき、システム全体の小型化が図られる。   For example, according to the experiments by the present inventors, a digestion tank 2 capable of treating sludge having a TS concentration of 6 to 10 wt% is a high-concentration digester, so that conventional sludge having a TS concentration of about 2 to 4 wt% is treated. Since the volume of the digestion tank 2 can be reduced to about 1/2 to 1/8 of the digestion tank for digestion of sludge, the installation space can be reduced and the entire system can be downsized.

次に、第1の実施の形態に係る嫌気性消化槽2の立ち上げ方法について、図3を参照しながら説明する。   Next, a method for starting up the anaerobic digester 2 according to the first embodiment will be described with reference to FIG.

まず、消化槽2に水又は種汚泥の単独又は両方を張り、嫌気状態下で加温する。具体的には、例えば、消化槽2に水又は種汚泥の単独又は両方を消化槽に設置された撹拌装置にて撹拌可能な水位まで張った後、消化槽2内の空気を窒素等の不活性ガスで置換することにより、消化槽2内を嫌気性状態とすることができる。   First, water or seed sludge alone or both are put on the digestion tank 2 and heated under anaerobic conditions. Specifically, for example, water or seed sludge alone or both in the digestion tank 2 is stretched to a stirrable water level with a stirrer installed in the digestion tank, and then the air in the digestion tank 2 is infused with nitrogen or the like. By substituting with the active gas, the inside of the digestion tank 2 can be brought into an anaerobic state.

消化槽2に水又は種汚泥の単独又は両方を張る工程においては、消化槽2には図示されていない撹拌装置及び加温装置が一般的に備えられており、撹拌装置及び加温装置が運転可能な水位まで水又は種汚泥の単独又は両方を消化槽2に満たすようにすることが望ましい。   In the process of applying water or seed sludge alone or both to the digester 2, the digester 2 is generally equipped with a stirrer and a heating device not shown, and the stirrer and the warmer are operated. It is desirable to fill the digester 2 with water or seed sludge alone or both to a possible water level.

更に消化槽2に水又は種汚泥の単独又は両方を張る工程においては、種汚泥を可能な限り消化槽2内に満たしておくことが望ましい。可能であれば、槽容量に対して体積基準で100%以下とし、必要量が確保できない場合は50%以下、更に確保できない場合は30%以下、より更に確保できない場合は10%以下の種汚泥を撹拌装置及び加温装置が運転可能な水位まで水とあわせて使用することが望ましい。種汚泥が確保できない場合は、水のみで消化槽2を満たしても、立ち上げは可能である。   Furthermore, in the process of stretching water or seed sludge alone or both in the digestion tank 2, it is desirable to fill the digestion tank 2 with the seed sludge as much as possible. If possible, the volume is 100% or less based on the volume of the tank capacity, 50% or less if the required amount cannot be secured, 30% or less if it cannot be secured, 10% or less if it cannot be secured further. Is preferably used together with water up to a water level at which the stirrer and heating device can operate. If seed sludge cannot be secured, it can be started up even if the digester 2 is filled with water alone.

次に、種汚泥と原汚泥とを濃縮機構1へ供給し、濃縮して濃縮汚泥を得る。原汚泥と種汚泥は濃縮機構1において、定常運転時の原汚泥TS濃度と同等以上にまで濃縮される。   Next, seed sludge and raw sludge are supplied to the concentration mechanism 1 and concentrated to obtain concentrated sludge. The raw sludge and seed sludge are concentrated in the concentration mechanism 1 to a level equal to or higher than the raw sludge TS concentration during steady operation.

次に、濃縮された濃縮汚泥を消化槽2へ投入する。投入される濃縮汚泥量は、濃縮機構1の処理能力の範囲内または濃縮機構1に供給可能な種汚泥量により投入可能な量とする。濃縮汚泥に含まれる原汚泥量は、以下に制限されるものではないが、定常運転時における原汚泥中の固形物量が1/3以下となる原汚泥量で開始する。汚泥投入前に種汚泥を消化槽容量に対して100%充填した場合を除き、消化槽の消化能力は定常運転時と比べ低いため、消化能力を超える有機分を一度に投入すると、消化槽2内の消化汚泥に有機酸が蓄積し、処理が安定しない場合がある。   Next, the concentrated concentrated sludge is charged into the digestion tank 2. The amount of concentrated sludge to be input is set to an amount that can be input depending on the processing capacity of the concentration mechanism 1 or the amount of seed sludge that can be supplied to the concentration mechanism 1. The amount of raw sludge contained in the concentrated sludge is not limited to the following, but starts with the amount of raw sludge in which the amount of solids in the raw sludge during steady operation is 1/3 or less. Except for the case where 100% of the seed sludge is filled with respect to the digestion tank volume before the sludge is charged, the digestion capacity of the digestion tank is lower than that during steady operation. In some cases, organic acid accumulates in the digested sludge and the treatment is not stable.

次に、濃縮機構1へ供給する原汚泥量を徐々に増加させることにより濃縮汚泥の投入量を増加させる。原汚泥量は、消化槽2内に存在する嫌気性微生物の増殖を考慮して、消化槽中の固形物量の10%以下、望ましくは4〜6%を目安として徐々に増やすことが好ましい。消化槽2では、消化槽2で発生する消化ガスの発生量に注意しながら消化ガス中の炭酸ガスの濃度、消化槽2内の汚泥濃度、有機酸及びpHなどを定期的に測定し、消化の進行状態を観察する。   Next, the input amount of concentrated sludge is increased by gradually increasing the amount of raw sludge supplied to the concentration mechanism 1. In consideration of the growth of anaerobic microorganisms present in the digestion tank 2, the amount of raw sludge is preferably gradually increased by 10% or less, preferably 4 to 6% of the solid content in the digestion tank. In digestion tank 2, paying attention to the amount of digestion gas generated in digestion tank 2, the concentration of carbon dioxide in digestion gas, the concentration of sludge in digestion tank 2, the organic acid and pH, etc. are measured regularly. Observe the progress of.

消化槽2内の温度及びpHは、汚泥中に含まれる嫌気性微生物(メタン発酵菌)の種類や投入される汚泥の汚泥負荷及び汚泥濃度等の条件に応じて適宜設定できる。温度は、一般的には25〜65℃、好ましくは30〜40℃である。高温菌の場合は50〜60℃である。pHは一般的には6.5〜8、好ましくは6.8〜7.6である。   The temperature and pH in the digestion tank 2 can be appropriately set according to conditions such as the type of anaerobic microorganisms (methane fermentation bacteria) contained in the sludge, the sludge load of the sludge to be input, and the sludge concentration. The temperature is generally 25 to 65 ° C, preferably 30 to 40 ° C. In the case of thermophilic bacteria, the temperature is 50 to 60 ° C. The pH is generally 6.5 to 8, preferably 6.8 to 7.6.

消化槽2は一般的に投入された汚泥量と同量の汚泥をオーバーフロー又はポンプ等による引抜により消化槽外に排出させる。通常は後段設備へ移送されるが、立ち上げ初期の低濃度の汚泥は最初沈殿池20へ返送され原水と共に処理されることもある。   The digestion tank 2 generally discharges the same amount of sludge as the amount of the introduced sludge to the outside of the digestion tank by overflow or extraction by a pump or the like. Usually, it is transferred to the latter stage equipment, but the low concentration sludge at the start-up stage is first returned to the settling basin 20 and may be treated together with the raw water.

種汚泥は可能な限り濃縮機構1へ供給することが望ましい。しかしながら、原汚泥と種汚泥の総量が濃縮機構1の処理能力を超える場合は、種汚泥の供給量を減らし濃縮機構1の処理能力範囲内で濃縮し消化槽2へ投入する。原汚泥の供給量が定常運転時の量に達し、消化槽2内の槽内汚泥濃度が安定した時点で、立ち上げ作業完了とする。   It is desirable to supply seed sludge to the concentration mechanism 1 as much as possible. However, when the total amount of raw sludge and seed sludge exceeds the processing capacity of the concentration mechanism 1, the supply amount of seed sludge is reduced and concentrated within the processing capacity range of the concentration mechanism 1 and put into the digester 2. When the supply amount of the raw sludge reaches the amount during steady operation and the sludge concentration in the digestion tank 2 is stabilized, the start-up operation is completed.

第1の実施の形態に係る嫌気性消化システム及びこれを用いた立ち上げ方法によれば、消化反応が安定した種汚泥と原汚泥とが消化槽2へ投入されるため、原汚泥量の投入量を少なくする必要のある立ち上げ当初から定常運転時の汚泥投入量に近い高濃度化された汚泥を消化槽2へ投入することができる。これにより、早期に消化槽2内の槽内汚泥濃度の高濃度化が図れる。また、既設消化槽4の消化汚泥を種汚泥として利用できるため、消化反応の阻害が少ない。   According to the anaerobic digestion system and the start-up method using the same according to the first embodiment, seed sludge and raw sludge having a stable digestion reaction are input to the digestion tank 2, so that the amount of raw sludge is input. The sludge having a high concentration close to the amount of sludge input during steady operation can be input to the digestion tank 2 from the start-up when it is necessary to reduce the amount. Thereby, high concentration of the sludge density | concentration in the tank in the digestion tank 2 can be achieved at an early stage. Moreover, since the digested sludge of the existing digester 4 can be used as seed sludge, there is little inhibition of the digestion reaction.

更に、第1の実施の形態に係る嫌気性消化槽の立ち上げ方法によれば、種汚泥と原汚泥との混合汚泥を濃縮しながら消化槽2へ投入して立ち上げを行うため、例えば少量の種汚泥が継続的に得られる場合等に特に好適に用いられる。即ち、第1の実施の形態に係る嫌気性消化槽の立ち上げ方法によれば、少量の種汚泥を原汚泥と混合させて濃縮した後に消化槽2へ供給する態様を用いることにより、消化槽2へ種汚泥を投入する場合に、初期に大量に種汚泥を移送して投入する必要がなく、常に安定した濃度の汚泥を消化槽2内へ供給することができる。例えば、新規の消化槽に種汚泥を入れる場合、消化槽2の容量に対して1/35〜1/12程度の量の種汚泥は得られないが、継続的に少量の種汚泥が得られる場合などに実施することで、効果を更に発揮できる。   Furthermore, according to the start-up method of the anaerobic digester according to the first embodiment, since the mixed sludge of seed sludge and raw sludge is put into the digester 2 while being concentrated, the start-up is performed. It is particularly preferably used when the seed sludge is continuously obtained. That is, according to the start-up method of the anaerobic digester according to the first embodiment, by using a mode in which a small amount of seed sludge is mixed with the raw sludge and concentrated and then supplied to the digester 2, the digester When seed sludge is charged to 2, it is not necessary to transfer and sludge the seed sludge in a large amount in the initial stage, and a sludge having a stable concentration can be always supplied into the digestion tank 2. For example, when seed sludge is put into a new digester, seed sludge in an amount of about 1/35 to 1/12 of the capacity of the digester 2 cannot be obtained, but a small amount of seed sludge is continuously obtained. The effect can be further demonstrated by carrying out in some cases.

更に、第1の形態に係る方法によれば、濃縮機構1にて凝集剤を使用する場合の添加率は、汚泥中に含まれる固形物量に対して重量基準で0.2〜1.5%程度とすることが好ましい。汚泥に凝集剤を多量に添加しすぎると汚泥中の有機分と嫌気性微生物との接触効率の低下及び嫌気性微生物の活性阻害が発生し、汚泥の分解が阻害される、即ち、消化阻害が発生する場合がある。逆に凝集剤の添加量が少なすぎると、凝集剤添加による効果が十分に得られない場合がある。汚泥の成分によって異なるが、濃縮機構1にて使用する凝集剤の添加率としては、ある一実施態様においては重量基準で0.3〜1.0%とすることができ、別の一実施態様においては0.4〜0.7%とすることができる。   Furthermore, according to the method according to the first embodiment, the addition rate when the flocculant is used in the concentration mechanism 1 is 0.2 to 1.5% on a weight basis with respect to the amount of solids contained in the sludge. It is preferable to set the degree. If too much flocculant is added to the sludge, the contact efficiency between the organic components in the sludge and the anaerobic microorganisms will be reduced and the activity of the anaerobic microorganisms will be inhibited, and the decomposition of the sludge will be inhibited. May occur. Conversely, if the amount of the flocculant added is too small, the effect due to the addition of the flocculant may not be sufficiently obtained. Although depending on the components of the sludge, the addition rate of the flocculant used in the concentration mechanism 1 can be 0.3 to 1.0% on a weight basis in one embodiment, and another embodiment In the range of 0.4 to 0.7%.

(第2の実施の形態)
本発明の第2の実施の形態に係る嫌気性処理システムは、図4に示すように、原汚泥を濃縮して濃縮汚泥を得る濃縮機構1と、濃縮汚泥を嫌気性消化処理する消化槽2と、消化槽2と濃縮機構1との間に配置され、消化槽2から引き抜かれた引抜汚泥の一部を濃縮機構1へ循環させる配管3とを備える。濃縮機構1及び消化槽2の構成は図3に示す構成と実質的に同様であるので説明を省略する。
(Second Embodiment)
As shown in FIG. 4, the anaerobic treatment system according to the second embodiment of the present invention includes a concentration mechanism 1 that concentrates raw sludge to obtain concentrated sludge, and a digester 2 that performs anaerobic digestion of the concentrated sludge. And a pipe 3 that is disposed between the digestion tank 2 and the concentration mechanism 1 and circulates a part of the extracted sludge extracted from the digestion tank 2 to the concentration mechanism 1. Since the structure of the concentration mechanism 1 and the digester 2 is substantially the same as the structure shown in FIG.

消化槽2内の汚泥は引き抜かれた後、引き抜かれた汚泥(「引抜汚泥」と称する)が消化槽2の後段に設置された後段設備へと送られて水処理される一方で、引抜汚泥の一部又は全部が配管3を介して濃縮機構1又は濃縮機構1の前段に接続された配管3に返送されるように構成されている。   After the sludge in the digestion tank 2 is extracted, the extracted sludge (referred to as “extracted sludge”) is sent to the subsequent equipment installed in the subsequent stage of the digestion tank 2 for water treatment, while the extracted sludge is extracted. A part or all of the above is returned to the concentrating mechanism 1 or the pipe 3 connected to the preceding stage of the concentrating mechanism 1 via the pipe 3.

引抜汚泥は、消化槽2で処理する汚泥の汚泥濃度にもよるが、消化処理が定常状態での消化汚泥TS濃度として9wt%以下(即ち含水率91wt%以上)である。一般的な嫌気性消化処理の消化汚泥TS濃度は、典型的には0.5〜9wt%(含水率91〜99.5wt%)であり、更に典型的には2〜9wt%(含水率91〜98wt%)である。高濃度嫌気性消化処理の消化汚泥TS濃度は、典型的にはより更に典型的には3〜7wt%(含水率93〜97wt%)である。   The drawn sludge has a digested sludge TS concentration of 9 wt% or less (that is, a moisture content of 91 wt% or more) in a steady state, although it depends on the sludge concentration of the sludge treated in the digestion tank 2. The digested sludge TS concentration of a general anaerobic digestion treatment is typically 0.5 to 9 wt% (water content 91 to 99.5 wt%), and more typically 2 to 9 wt% (water content 91). ~ 98 wt%). The concentration of digested sludge TS in the high concentration anaerobic digestion treatment is typically 3 to 7 wt% (water content 93 to 97 wt%) more typically.

配管3には図示しないポンプ機構が配置されている。上述のように、本実施形態に係る引抜汚泥のTS濃度は9wt%以下であるため、特許文献1に記載されるような脱水汚泥に比べて汚泥濃度が低く、搬送が容易であり、配管3及びポンプに詰まりを生じさせることを抑制しながら配管圧送することができる。   A pump mechanism (not shown) is disposed in the pipe 3. As described above, since the TS concentration of the drawn sludge according to the present embodiment is 9 wt% or less, the sludge concentration is lower than that of the dehydrated sludge as described in Patent Document 1, and transportation is easy. In addition, the piping can be fed while suppressing clogging of the pump.

更に、濃縮機構1にて処理された濃縮汚泥においてもTS濃度は12%以下であり、搬送が容易である。その結果、含水率の低い脱水汚泥を消化槽へ搬送機等を用いて搬送する場合に比べて、引抜汚泥の返送に係わる設備の簡略化が可能である。   Furthermore, even in the concentrated sludge treated by the concentration mechanism 1, the TS concentration is 12% or less, and is easy to transport. As a result, compared with the case where dehydrated sludge having a low water content is transported to the digestion tank using a transporter or the like, it is possible to simplify the equipment for returning the extracted sludge.

本実施形態に係る立ち上げ方法によれば、消化槽2内の汚泥の一部を引き抜いて濃縮機構1へ返送し、原汚泥とともに濃縮機構1で所定の濃度まで濃縮し、消化槽2へ再投入することで、当該消化槽からの引抜汚泥を高濃度の種汚泥として活用することができる。その結果、消化槽2内の環境を大きく変動させることなく、消化槽2の早期立ち上げが実現できる。   According to the start-up method according to the present embodiment, a part of the sludge in the digestion tank 2 is extracted and returned to the concentration mechanism 1, concentrated together with the raw sludge to a predetermined concentration by the concentration mechanism 1, and then returned to the digestion tank 2. By putting it in, the extracted sludge from the digestion tank can be used as high-concentration seed sludge. As a result, early start-up of the digester 2 can be realized without greatly changing the environment in the digester 2.

次に、本発明の第2の実施の形態に係る嫌気性消化槽の立ち上げ方法について、図4を参照しながら説明する。   Next, a method for starting an anaerobic digester according to the second embodiment of the present invention will be described with reference to FIG.

まず、消化槽2に水又は種汚泥の単独又は両方を張り、嫌気状態下で加温する。具体的には、例えば、消化槽2に水又は種汚泥の単独又は両方を消化槽2に設置された撹拌装置にて撹拌可能な水位まで張った後、消化槽2内の空気を窒素等の不活性ガスで置換することにより、消化槽2内を嫌気性状態とすることができる。   First, water or seed sludge alone or both are put on the digestion tank 2 and heated under anaerobic conditions. Specifically, for example, water or seed sludge alone or both in the digestion tank 2 is stretched to a stirrable water level with a stirrer installed in the digestion tank 2, and then the air in the digestion tank 2 is changed to nitrogen or the like. By substituting with the inert gas, the inside of the digestion tank 2 can be brought into an anaerobic state.

次に、原汚泥を濃縮機構1へ供給し、原汚泥を濃縮して濃縮汚泥を得る。濃縮機構1においては、まず、定常運転時の原汚泥TS濃度と同等以上に原汚泥を濃縮処理する。   Next, the raw sludge is supplied to the concentration mechanism 1, and the raw sludge is concentrated to obtain the concentrated sludge. In the concentration mechanism 1, first, the raw sludge is concentrated to a level equal to or higher than the raw sludge TS concentration during steady operation.

次に、濃縮汚泥を消化槽2へ投入する。濃縮汚泥の初期の投入汚泥量は、以下に制限されるものではないが、一般的な方法の一例として定常運転時における原汚泥中の固形物量が1/3以下となる原汚泥量で開始する。   Next, the concentrated sludge is charged into the digestion tank 2. The initial input amount of concentrated sludge is not limited to the following, but as an example of a general method, the amount of solid sludge in the raw sludge during steady operation starts with an amount of raw sludge that is 1/3 or less. .

次に、消化槽2に投入する濃縮汚泥量を徐々に上昇させる。消化槽2では、消化槽2で発生する消化ガスの発生量に注意しながら消化ガス中の炭酸ガスの濃度、消化槽2内の汚泥濃度、有機酸及びpHなどを定期的に測定し、消化の進行状態を観察する。   Next, the amount of concentrated sludge thrown into the digester 2 is gradually increased. In digestion tank 2, paying attention to the amount of digestion gas generated in digestion tank 2, the concentration of carbon dioxide in digestion gas, the concentration of sludge in digestion tank 2, the organic acid and pH, etc. are measured regularly. Observe the progress of.

濃縮汚泥の消化槽2への投入量を徐々に上昇させ、消化槽2内の槽内汚泥TS濃度が濃縮機構1において濃縮可能な濃度に達した後に、消化槽2から排出された引抜汚泥の一部または全部を前記原汚泥とともに濃縮機構1へ供給し、濃縮処理し、消化槽2へ返送する。その他の引抜汚泥は後段にある水処理設備又は汚泥処理設備(図4の後段設備)へ送られる。   The amount of the extracted sludge discharged from the digestion tank 2 is gradually increased after the amount of the concentrated sludge input to the digestion tank 2 is gradually increased and the concentration of the sludge TS in the digestion tank 2 reaches a concentration that can be concentrated in the concentration mechanism 1. A part or the whole is supplied together with the raw sludge to the concentration mechanism 1, concentrated, and returned to the digester 2. The other extracted sludge is sent to a water treatment facility or a sludge treatment facility (the latter-stage facility in FIG. 4) in the subsequent stage.

引抜汚泥の全汚泥量に対する濃縮機構1へ供給する引抜汚泥の量は、濃縮機構1の処理能力の範囲内で可能な限り供給することが望ましい。処理によりそれぞれ異なるため以下に制限されるものではないが、消化槽へ投入される汚泥量と消化槽から引き抜かれる汚泥量が概ね同量となることを勘案すると、例えば原汚泥量と引抜汚泥との総量が定常運転時の汚泥投入量より少なくなる立ち上げ初期においては引抜汚泥の100%を濃縮機構1へ供給し、原汚泥量を増加させ原汚泥量と引抜汚泥との総量が定常運転時の汚泥投入量より多くなる立ち上げ後期においては、引抜汚泥の割合を徐々に低下させ定常運転時の汚泥投入量を消化槽へ投入することが望ましい。濃縮汚泥の汚泥負荷が計画投入汚泥負荷にまで到達したら、立ち上げ完了とする。   The amount of the extracted sludge supplied to the concentration mechanism 1 with respect to the total amount of the extracted sludge is preferably supplied as much as possible within the processing capacity of the concentration mechanism 1. Although it is different depending on the treatment, it is not limited to the following. In the initial stage of startup when the total amount of sludge is less than the amount of sludge input during steady operation, 100% of the extracted sludge is supplied to the concentrating mechanism 1 to increase the amount of raw sludge and the total amount of raw sludge and extracted sludge is In the latter stage of startup, which is greater than the sludge input amount, it is desirable to gradually reduce the ratio of the extracted sludge and to input the sludge input amount during steady operation to the digester. When the sludge load of the concentrated sludge reaches the planned input sludge load, the start-up is completed.

第2の実施の形態に係る嫌気性消化槽の立ち上げ方法によれば、消化槽2から引き抜かれた引抜汚泥の一部を原汚泥とともに濃縮し、消化槽2へ返送する。そのため、消化槽2へ投入可能な種汚泥が少量又は無い場合においても、消化槽2内の汚泥の濃度を早期に上昇させることができ、立ち上げのための期間を短縮できる。   According to the start-up method of the anaerobic digester according to the second embodiment, part of the extracted sludge extracted from the digester 2 is concentrated together with the raw sludge and returned to the digester 2. Therefore, even when there is little or no seed sludge that can be introduced into the digestion tank 2, the concentration of sludge in the digestion tank 2 can be increased at an early stage, and the startup period can be shortened.

更に、第2の実施の形態に係る方法によれば、含水率の高い(例えば約91%以上)引抜汚泥を濃縮機構1へ返送するため、ポンプによる配管圧送が容易であり、単純な装置で早期の装置立ち上げができる。また、引抜汚泥の固液分離処理も、消化槽2近傍に配置された濃縮機構1で行うことにより、装置全体を小型化することができる。   Furthermore, according to the method according to the second embodiment, the drawn sludge having a high water content (for example, about 91% or more) is returned to the concentrating mechanism 1, so that piping pumping by a pump is easy and a simple device is used. Early equipment startup is possible. Further, the solid-liquid separation process of the drawn sludge is also performed by the concentration mechanism 1 disposed in the vicinity of the digestion tank 2, whereby the entire apparatus can be reduced in size.

更に、第2の実施の形態に係る方法によれば、濃縮機構1で濃縮された汚泥の含水率は特許文献1で開示される脱水汚泥の含水率に比べ非常に高いため、液中に溶解したアルカリ分のロスが小さくて済む。例えば、含水率97%の消化汚泥を含水率92%(TS濃度8%)とする濃縮汚泥と含水率85%(TS濃度15%)とする脱水汚泥とでは、濃縮汚泥の方が脱水汚泥と比べアルカリ分が約2倍多くなる。そのため、消化槽2において添加するアルカリ剤の使用量も少なく又は使用しなくてすみ、槽内pHの保持も容易である。   Furthermore, according to the method according to the second embodiment, the water content of the sludge concentrated by the concentration mechanism 1 is very high compared to the water content of the dewatered sludge disclosed in Patent Document 1, so that it is dissolved in the liquid. The loss of alkali content is small. For example, in the case of concentrated sludge with digested sludge having a moisture content of 97% and moisture content of 92% (TS concentration 8%) and dehydrated sludge having a moisture content of 85% (TS concentration 15%), the concentrated sludge is more dehydrated sludge. The alkali content is about twice as high. For this reason, the amount of the alkaline agent added in the digestion tank 2 is small or unnecessary, and it is easy to maintain the pH in the tank.

更に、第2の実施の形態に係る方法によれば、分解されアルカリ成分となる有機物を含む原汚泥も濃縮機構1で濃縮するため消化槽2の総アルカリ度も早期に上昇するため、槽内pHの保持がより容易となる。   Furthermore, according to the method according to the second embodiment, since the raw sludge containing the organic matter that is decomposed and becomes an alkali component is also concentrated by the concentration mechanism 1, the total alkalinity of the digestion tank 2 also increases at an early stage. It becomes easier to maintain the pH.

(変形例)
図5に示すように、第2の実施の形態の変形例に係る嫌気性消化システムは、種汚泥を濃縮機構1へ供給する種汚泥供給手段5を備える点が、図4に示す嫌気性消化システムと異なる。他は、図4の嫌気性消化システムと実質的に同様であるので、重複記載を省略する。
(Modification)
As shown in FIG. 5, the anaerobic digestion system according to the modification of the second embodiment is provided with seed sludge supply means 5 for supplying seed sludge to the concentration mechanism 1. Different from the system. Since others are substantially the same as the anaerobic digestion system of FIG. 4, duplicate description is abbreviate | omitted.

第2の実施の形態の変形例に係る嫌気性消化システム及び立ち上げ方法によれば、種汚泥を原汚泥とともに濃縮機構1で濃縮することにより、濃縮汚泥の汚泥濃度をより早期に高濃度化させ、消化槽2の更なる早期立ち上げを行うことができる。また、図5に示すシステムでは、消化槽2へ投入される原汚泥、引抜汚泥、種汚泥を一旦、全て濃縮機構1で濃縮させた後、消化槽2へ供給することができるので、性状の異なる汚泥を別々に消化槽2へ投入する場合に比べて、消化槽2内の状態を安定的に維持することができる。   According to the anaerobic digestion system and start-up method according to the modification of the second embodiment, the sludge concentration of the concentrated sludge is increased earlier by concentrating the seed sludge together with the raw sludge with the concentration mechanism 1. The digester 2 can be further started up earlier. Further, in the system shown in FIG. 5, the raw sludge, the extracted sludge, and the seed sludge that are put into the digestion tank 2 can be once concentrated in the concentration mechanism 1 and then supplied to the digestion tank 2. Compared to the case where different sludges are separately charged into the digestion tank 2, the state in the digestion tank 2 can be stably maintained.

(その他の変形例)
本発明は上記の実施の形態によって記載したが、この開示の一部をなす論述及び図面はこの発明を限定するものであると理解すべきではない。この開示から当業者には様々な代替実施の形態及び運用技術が明らかとなろう。
(Other variations)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments and operational techniques will be apparent to those skilled in the art.

上述の実施の形態では、消化槽2の立ち上げに際し、まずは、消化槽2に水又は種汚泥の単独又は両方を張って嫌気性条件下で加温する工程を説明したが、種汚泥を用いる場合には、消化槽2に種汚泥をそのまま投入するのではなく、種汚泥を濃縮機構1により予め濃縮した後に消化槽2へ供給することが好ましい。消化槽2内へ供給する種汚泥を濃縮機構1において予め濃縮させることで、未濃縮の種汚泥を供給した場合に比べて消化槽2内をより高い汚泥濃度とすることが出来るため、より早期に立ち上げを完了することができる。   In the above-described embodiment, when the digester 2 is started up, first, the process of heating the digester 2 alone or both with water or seed sludge and heating under anaerobic conditions is described, but the seed sludge is used. In this case, it is preferable that the seed sludge is not supplied as it is to the digestion tank 2 but is supplied to the digestion tank 2 after the seed sludge is concentrated by the concentration mechanism 1 in advance. By concentrating the seed sludge to be supplied into the digester 2 in the concentration mechanism 1 in advance, the digester 2 can have a higher sludge concentration compared to the case where unconcentrated seed sludge is supplied. You can complete the launch.

例えば、使用できる種汚泥量が当該消化槽2の容量以上ある場合には、濃縮機構1で減容化してから消化槽2へ供給することで、消化槽内の汚泥濃度を定格以上とすることが可能となる場合もある。この場合は、立ち上げ自体が不要となると共に、定格汚泥量以上の原汚泥投入を行っても消化処理が可能となる。   For example, if the amount of seed sludge that can be used is greater than or equal to the capacity of the digestion tank 2, the volume of sludge in the digestion tank is set to a rating or higher by supplying the digestion tank 2 after reducing the volume with the concentration mechanism 1. May be possible. In this case, startup itself becomes unnecessary, and digestion can be performed even if raw sludge exceeding the rated sludge amount is supplied.

さらに、消化槽2が高濃度消化槽の場合、一般的な種汚泥と比べ消化槽内の汚泥濃度を非常に高くする必要がある。高濃度消化槽は一般的な消化槽と比べ小型化となるため、例えば、同一処理場に設置された停止中の消化槽内の消化汚泥を使用できる場合は、大量の種汚泥を減容化して使用することができ、高濃度消化槽であっても早期に立ち上げを完了又は立ち上げ不要とすることができる。   Furthermore, when the digestion tank 2 is a high concentration digestion tank, it is necessary to make the sludge density | concentration in a digestion tank very high compared with a general seed sludge. Since high-concentration digesters are smaller than general digesters, for example, if digested sludge in a suspended digester installed in the same treatment plant can be used, the volume of seed sludge can be reduced. Even in a high-concentration digester, the start-up can be completed early or no start-up is required.

以下、本発明の実施例について説明するが、下記の実施例は本発明及びその利点をより良く理解するための例示であって、本発明が限定されることを意図するものではない。   Hereinafter, examples of the present invention will be described. However, the following examples are examples for better understanding of the present invention and its advantages, and are not intended to limit the present invention.

従来及び本発明に係る嫌気性消化システムを用いた消化槽の立ち上げ方法のシミュレーションを行った。表1にシミュレーション条件を示す。実施例1は、図4に示す嫌気性消化システムを用いて消化槽2の立ち上げを行ったものである。実施例2は、図3に示す嫌気性消化システムを用いて消化槽2の立ち上げを行ったものである。実施例3は、図5に示す嫌気性消化システムを用いて消化槽2の立ち上げを行ったものである。比較例1は、消化槽2に直接原汚泥を投入した場合の例である。比較例2は、消化槽2で得られた引抜汚泥を脱水して脱水汚泥とした後に、脱水汚泥を消化槽2へ返送した場合の例である。   A simulation of a digestion tank startup method using an anaerobic digestion system according to the related art and the present invention was performed. Table 1 shows the simulation conditions. In Example 1, the digestion tank 2 was started up using the anaerobic digestion system shown in FIG. In Example 2, the digestion tank 2 was started up using the anaerobic digestion system shown in FIG. In Example 3, the digestion tank 2 was started up using the anaerobic digestion system shown in FIG. Comparative Example 1 is an example in which raw sludge is directly charged into the digester 2. Comparative Example 2 is an example in which the dewatered sludge obtained in the digestion tank 2 is dehydrated to obtain dehydrated sludge, and then the dehydrated sludge is returned to the digestion tank 2.

実施例1〜3、比較例1、2ともに立ち上げ初期に、別の消化槽からの消化汚泥及び脱離液を含む種汚泥を消化槽容量の50%添加した場合について評価した。立ち上げに要した期間(立ち上げ期間)の試算結果を表2に示し、時間経過に対する消化槽の槽内汚泥TS濃度の変化を図6に、総アルカリ度の変化を図7に、有機性高分子凝集剤残存率を図8に示す。   In each of Examples 1 to 3 and Comparative Examples 1 and 2, the case where 50% of the digestion tank capacity of digestion sludge from another digestion tank and seed sludge containing desorbed liquid was added was evaluated. Table 2 shows the results of trial calculation of the period required for start-up (start-up period). Fig. 6 shows the change in the sludge TS concentration in the digestion tank over time, and Fig. 7 shows the change in total alkalinity. The polymer flocculant residual rate is shown in FIG.

実施例1〜3、比較例1、2ともに総アルカリ度は有機物の分解過程で生成するアルカリ分を換算した値とし、種汚泥中の総アルカリ度は2650mg‐CaCO3/Lとした。 In all of Examples 1 to 3 and Comparative Examples 1 and 2, the total alkalinity was a value obtained by converting the alkali content generated during the decomposition of the organic matter, and the total alkalinity in the seed sludge was 2650 mg-CaCO 3 / L.

実施例1〜3、比較例1、2ともに原汚泥中の有機性高分子凝集剤の残存率は重量基準として0.2%とした。実施例1〜3の汚泥濃縮にて添加する有機性高分子凝集剤添加率を重量基準で0.5%、比較例2の汚泥脱水にて添加する添加率を2.0%とした。   In Examples 1 to 3 and Comparative Examples 1 and 2, the residual rate of the organic polymer flocculant in the raw sludge was 0.2% on a weight basis. The organic polymer flocculant addition rate added by sludge concentration in Examples 1 to 3 was 0.5% on a weight basis, and the addition rate added by sludge dehydration in Comparative Example 2 was set to 2.0%.

1 :濃縮機構
2 :嫌気性消化槽
3 :配管
4 :既設消化槽
5 :種汚泥供給手段
20 :最初沈殿池
30 :反応タンク
40 :最終沈殿池
50 :機械濃縮機構
60 :重力濃縮機構
70 :混合槽
80 :機械濃縮機構
90 :消化槽
1: Concentration mechanism 2: Anaerobic digestion tank 3: Pipe 4: Existing digestion tank 5: Seed sludge supply means 20: First sedimentation tank 30: Reaction tank 40: Final sedimentation tank 50: Mechanical concentration mechanism 60: Gravity concentration mechanism 70: Mixing tank 80: Mechanical concentration mechanism 90: Digestion tank

Claims (10)

処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、
種汚泥と原汚泥とを濃縮し、濃縮汚泥を得ることと、
前記濃縮汚泥を前記消化槽に投入することと、
前記消化槽への前記濃縮汚泥の投入量を増加させることと
を含む嫌気性消化槽の立ち上げ方法。
Throwing water and / or seed sludge into the digester where the concentrating mechanism is located in the previous stage of the treatment flow;
Concentrating seed sludge and raw sludge to obtain concentrated sludge;
Throwing the concentrated sludge into the digester;
Increasing the input amount of the concentrated sludge to the digester, and starting up the anaerobic digester.
処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、
原汚泥を濃縮し、濃縮汚泥を得ることと、
前記濃縮汚泥を前記消化槽に投入することと、
前記消化槽内の汚泥の一部を引き抜いて引抜汚泥を得ることと、
前記引抜汚泥の少なくとも一部を前記原汚泥とともに濃縮し、前記消化槽へ返送することと
を含む嫌気性消化槽の立ち上げ方法。
Throwing water and / or seed sludge into the digester where the concentrating mechanism is located in the previous stage of the treatment flow;
Concentrating raw sludge to obtain concentrated sludge,
Throwing the concentrated sludge into the digester;
Extracting a portion of the sludge in the digestion tank to obtain a drawn sludge;
Concentrating at least a part of the extracted sludge together with the raw sludge and returning it to the digester, a method for starting an anaerobic digester.
処理フローの前段に濃縮機構が配置された消化槽に水及び/又は種汚泥を投入することと、
種汚泥と原汚泥とを濃縮し、濃縮汚泥を得ることと、
前記濃縮汚泥を前記消化槽に投入することと、
前記消化槽から汚泥の一部を引き抜いて引抜汚泥を得ることと、
前記引抜汚泥の少なくとも一部を前記種汚泥及び前記原汚泥とともに濃縮し、前記消化槽へ返送することと、
前記消化槽へ投入する濃縮汚泥の投入量を増加させることと
を含む嫌気性消化槽の立ち上げ方法。
Throwing water and / or seed sludge into the digester where the concentrating mechanism is located in the previous stage of the treatment flow;
Concentrating seed sludge and raw sludge to obtain concentrated sludge;
Throwing the concentrated sludge into the digester;
Extracting a portion of the sludge from the digestion tank to obtain a drawn sludge;
Concentrating at least a portion of the extracted sludge together with the seed sludge and the raw sludge and returning it to the digester;
Increasing the input amount of the concentrated sludge to be input to the digester, and starting up the anaerobic digester.
前記消化槽に水及び/又は種汚泥を投入する際、前記種汚泥を投入する場合には、前記種汚泥を前記濃縮機構において濃縮処理した後に前記消化槽へ投入することを含む請求項1〜3のいずれか1項に記載の嫌気性消化槽の立ち上げ方法。   When introducing water and / or seed sludge into the digestion tank, when the seed sludge is charged, the seed sludge is concentrated in the concentration mechanism and then charged into the digestion tank. 4. The method for starting an anaerobic digester according to any one of items 3 to 3. 前記種汚泥として、既設の消化槽から発生する汚泥を用いることを含む請求項1〜4のいずれか1項に記載の嫌気性消化槽の立ち上げ方法。   The start-up method of the anaerobic digestion tank of any one of Claims 1-4 including using the sludge generate | occur | produced from the existing digestion tank as said seed sludge. 前記濃縮機構に供給される汚泥の固形物量に対し、凝集剤を0.2〜1.5質量%添加して濃縮処理することを含む請求項1〜5のいずれか1項に記載の嫌気性消化槽の立ち上げ方法。   The anaerobic property according to any one of claims 1 to 5, comprising adding a flocculant in an amount of 0.2 to 1.5% by mass to the solid amount of sludge supplied to the concentration mechanism. How to start up the digester. 前記消化槽に、汚泥濃度4〜12質量%の濃縮汚泥を供給することを含む請求項1〜6のいずれか1項に記載の嫌気性消化槽の立ち上げ方法。   The start-up method of the anaerobic digester according to any one of claims 1 to 6, comprising supplying concentrated sludge having a sludge concentration of 4 to 12% by mass to the digester. 原汚泥を濃縮して濃縮汚泥を得る濃縮機構と、前記濃縮汚泥を嫌気性消化処理する消化槽と、消化槽と前記濃縮機構との間に配置され、前記消化槽から引き抜かれた引抜汚泥の一部を前記濃縮機構へ循環させる配管とを備えることを特徴とする嫌気性消化システム。   A concentration mechanism for concentrating the raw sludge to obtain a concentrated sludge, a digestion tank for anaerobically digesting the concentrated sludge, a digestion tank disposed between the digestion tank and the concentration mechanism, and a drawn sludge extracted from the digestion tank An anaerobic digestion system comprising: a pipe that circulates a part to the concentration mechanism. 種汚泥を前記濃縮機構へ供給する汚泥供給手段を更に備える請求項8に記載の嫌気性消化システム。   The anaerobic digestion system according to claim 8, further comprising sludge supply means for supplying seed sludge to the concentration mechanism. 前記消化槽が、汚泥濃度1〜12質量%の汚泥を嫌気性消化処理して、0.5〜9質量%の消化汚泥を排出する消化槽である請求項8又は9に記載の嫌気性消化システム。   The anaerobic digestion according to claim 8 or 9, wherein the digester is a digester that performs anaerobic digestion of sludge having a sludge concentration of 1 to 12% by mass to discharge 0.5 to 9% by mass of digested sludge. system.
JP2018028159A 2018-02-20 2018-02-20 Anaerobic digestion start-up method and anaerobic digestion start-up system Active JP6954853B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2018028159A JP6954853B2 (en) 2018-02-20 2018-02-20 Anaerobic digestion start-up method and anaerobic digestion start-up system
JP2021159789A JP7228653B2 (en) 2018-02-20 2021-09-29 Anaerobic digestion tank start-up method and anaerobic digestion system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2018028159A JP6954853B2 (en) 2018-02-20 2018-02-20 Anaerobic digestion start-up method and anaerobic digestion start-up system

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP2021159789A Division JP7228653B2 (en) 2018-02-20 2021-09-29 Anaerobic digestion tank start-up method and anaerobic digestion system

Publications (3)

Publication Number Publication Date
JP2019141778A true JP2019141778A (en) 2019-08-29
JP2019141778A5 JP2019141778A5 (en) 2020-04-30
JP6954853B2 JP6954853B2 (en) 2021-10-27

Family

ID=67770769

Family Applications (2)

Application Number Title Priority Date Filing Date
JP2018028159A Active JP6954853B2 (en) 2018-02-20 2018-02-20 Anaerobic digestion start-up method and anaerobic digestion start-up system
JP2021159789A Active JP7228653B2 (en) 2018-02-20 2021-09-29 Anaerobic digestion tank start-up method and anaerobic digestion system

Family Applications After (1)

Application Number Title Priority Date Filing Date
JP2021159789A Active JP7228653B2 (en) 2018-02-20 2021-09-29 Anaerobic digestion tank start-up method and anaerobic digestion system

Country Status (1)

Country Link
JP (2) JP6954853B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112723695A (en) * 2020-11-06 2021-04-30 深圳市朗坤生物科技有限公司 Method for quickly starting anaerobic digestion system
JP7455278B1 (en) 2022-10-11 2024-03-25 三菱電機株式会社 Anaerobic digestion process monitoring system and anaerobic digestion process monitoring method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59109296A (en) * 1982-12-14 1984-06-23 Shinryo Air Conditioning Co Ltd Anaerobic digestion treatment
JP2001104999A (en) * 1999-10-07 2001-04-17 Kurita Water Ind Ltd Treatment of organic waste
JP2005046788A (en) * 2003-07-31 2005-02-24 Fuji Electric Holdings Co Ltd Methane fermentation method and apparatus
JP2009011993A (en) * 2007-07-09 2009-01-22 Takuma Co Ltd Method for starting up anaerobic digestion system
US20160214879A1 (en) * 2015-01-27 2016-07-28 Anaergia Inc. Treatment of waste products with anaerobic digestion

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0738994B2 (en) * 1987-04-08 1995-05-01 株式会社明電舎 Initial operation method of low temperature methane fermentation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59109296A (en) * 1982-12-14 1984-06-23 Shinryo Air Conditioning Co Ltd Anaerobic digestion treatment
JP2001104999A (en) * 1999-10-07 2001-04-17 Kurita Water Ind Ltd Treatment of organic waste
JP2005046788A (en) * 2003-07-31 2005-02-24 Fuji Electric Holdings Co Ltd Methane fermentation method and apparatus
JP2009011993A (en) * 2007-07-09 2009-01-22 Takuma Co Ltd Method for starting up anaerobic digestion system
US20160214879A1 (en) * 2015-01-27 2016-07-28 Anaergia Inc. Treatment of waste products with anaerobic digestion

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112723695A (en) * 2020-11-06 2021-04-30 深圳市朗坤生物科技有限公司 Method for quickly starting anaerobic digestion system
JP7455278B1 (en) 2022-10-11 2024-03-25 三菱電機株式会社 Anaerobic digestion process monitoring system and anaerobic digestion process monitoring method

Also Published As

Publication number Publication date
JP7228653B2 (en) 2023-02-24
JP2022000304A (en) 2022-01-04
JP6954853B2 (en) 2021-10-27

Similar Documents

Publication Publication Date Title
US9771292B2 (en) Treatment of waste products with anaerobic digestion
US6113789A (en) Pasteurization process
US9809481B2 (en) Treatment of waste products with anaerobic digestion
Cho et al. An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation
KR101616323B1 (en) Manufacturing system for power and fertilizer using livestock eretion
JP7228653B2 (en) Anaerobic digestion tank start-up method and anaerobic digestion system
JP2009214043A (en) Biological treatment method for organic waste liquid, and treatment device therefor
JP7440575B2 (en) Digestion equipment
JP5726576B2 (en) Method and apparatus for treating organic waste
JP7105136B2 (en) ORGANIC WASTE TREATMENT METHOD AND ORGANIC WASTE TREATMENT SYSTEM
KR101894502B1 (en) Apparatus for anaerobic digestion of organic wastes using anaerobic digestion remainder
KR101812448B1 (en) Anaerobic disgestion apparatus for treating food wastewater
KR100973786B1 (en) Anaerobic digestion method of organic waste having high salinity
JP2006075730A (en) Anaerobic treatment device
JP6359490B2 (en) Sewage treatment system and sewage treatment method
JP5301788B2 (en) Co-fermentation method
KR20160033967A (en) System for Reduction Treating and Energy Producing of Organic Waste
US20220259088A1 (en) High solids anaerobic digestion with post-digestion hydrolysis
JP2005313120A (en) Anaerobic treatment apparatus
KR100967842B1 (en) Method for production of methan gas from sewage sludge
KR100977020B1 (en) Apparatus and methods for successive disposal of food wastewater
KR200325153Y1 (en) High efficiency sludge dewatering equipment by high temperature sludge of anaerobic digester
JP2002045896A (en) Method for starting up dry process methane fermentation
CA3200837A1 (en) Two-stage anaerobic digestion processes and systems comprising ammonia removal for converting organic material into biogas
JP6212441B2 (en) Operation method of wet methane fermentation treatment facility for organic waste

Legal Events

Date Code Title Description
A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20200318

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20200318

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20210114

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20210202

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20210405

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20210831

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20210930

R150 Certificate of patent or registration of utility model

Ref document number: 6954853

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150