JPWO2004005199A1 - Method and apparatus for treating organic wastewater - Google Patents

Method and apparatus for treating organic wastewater Download PDF

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JPWO2004005199A1
JPWO2004005199A1 JP2004519204A JP2004519204A JPWO2004005199A1 JP WO2004005199 A1 JPWO2004005199 A1 JP WO2004005199A1 JP 2004519204 A JP2004519204 A JP 2004519204A JP 2004519204 A JP2004519204 A JP 2004519204A JP WO2004005199 A1 JPWO2004005199 A1 JP WO2004005199A1
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sludge
treatment
tank
ultrasonic
acid fermentation
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JP4456480B2 (en
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小林 琢也
琢也 小林
山下 茂樹
茂樹 山下
荒川 清美
清美 荒川
田中 俊博
俊博 田中
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Ebara Corp
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/12Activated sludge processes
    • C02F3/1205Particular type of activated sludge processes
    • C02F3/1221Particular type of activated sludge processes comprising treatment of the recirculated sludge
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/34Treatment of water, waste water, or sewage with mechanical oscillations
    • C02F1/36Treatment of water, waste water, or sewage with mechanical oscillations ultrasonic vibrations
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00Treatment of sludge; Devices therefor
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00Treatment of sludge; Devices therefor
    • C02F11/18Treatment of sludge; Devices therefor by thermal conditioning
    • 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
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/10Biological treatment of water, waste water, or sewage

Abstract

本発明は、超音波を用いた余剰汚泥処理において、余剰汚泥の可溶化をより促進させることのできる方法及び装置を提供することを目的とする。かかる目的を達成するための手段として、本発明は、生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥の処理方法であって、前記余剰汚泥の一部又は全量を、超音波処理と、酸発酵処理、化学処理及び加温処理の少なくとも一つとの組み合わせによって可溶化処理し、可溶化処理された汚泥を生物処理工程に返送することを特徴とする方法を提供する。An object of this invention is to provide the method and apparatus which can further promote solubilization of excess sludge in the excess sludge process using an ultrasonic wave. As a means for achieving such an object, the present invention provides a method for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, and a part of the surplus sludge. Alternatively, the total amount is solubilized by a combination of ultrasonic treatment and at least one of acid fermentation treatment, chemical treatment and heating treatment, and the solubilized sludge is returned to the biological treatment step. I will provide a.

Description

本発明は、下水や有機性の産業排水などの有機性廃水の生物処理に関し、特に余剰汚泥の発生量を削減できる有機性廃水の処理方法及び装置に関する。  The present invention relates to biological treatment of organic wastewater such as sewage and organic industrial wastewater, and more particularly to a method and apparatus for treating organic wastewater that can reduce the amount of excess sludge generated.

下水や有機性の産業排水は、通常、好気性生物処理法、硝化脱窒法、嫌気性生物処理法などの種々の生物処理法で処理することができる。有機性廃水の生物処理法は優れた処理方法であるが、その過程で大量の余剰汚泥が発生し、その発生量は、日本全体では年間1000万t以上となっている。通常、余剰汚泥は、脱水した後、埋め立て処分や焼却処分されているが、その処理コストは年々増加しており、排水全体のコストを上昇させる原因の一つとなっている。そのため近年、余剰汚泥の発生量を抑制する技術が注目されている。例えば、特開昭57−19719号公報では、余剰汚泥に超音波を照射することにより、余剰汚泥中の微生物の細胞膜を破壊し、内容物を液化有機物に変化させた後、これを生物処理槽に返送して生物処理により無機化することで余剰汚泥を減少させる方法が提案されている。超音波処理の他にも、例えば、ミルなどによって物理的に活性汚泥を微細化する方法や、汚泥を加温状態に保ち好熱細菌により汚泥を可溶化する方法(特開平11−90493号公報)、オゾンを作用させて汚泥を可溶化する方法(特開平6−206088号公報)など様々な汚泥の液化方法が発表されている。これら様々な手段により液化した汚泥を再び生物処理槽に戻して生物処理槽内の微生物により無機化することにより、余剰汚泥の発生量を減少させることができる。  Sewage and organic industrial wastewater can usually be treated by various biological treatment methods such as aerobic biological treatment, nitrification denitrification, and anaerobic biological treatment. The biological treatment method of organic wastewater is an excellent treatment method, but a large amount of excess sludge is generated in the process, and the generation amount is 10 million tons or more in Japan as a whole. Usually, surplus sludge is dewatered and then disposed of in landfills or incineration, but its treatment costs are increasing year by year, which is one of the causes of increasing the cost of the entire wastewater. Therefore, in recent years, a technique for reducing the amount of excess sludge generated has attracted attention. For example, in Japanese Patent Application Laid-Open No. 57-19719, the surplus sludge is irradiated with ultrasonic waves to destroy the cell membrane of microorganisms in the surplus sludge, and the contents are changed to liquefied organic matter. A method has been proposed in which excess sludge is reduced by returning it to water and making it mineral by biological treatment. In addition to ultrasonic treatment, for example, a method of physically refining activated sludge with a mill or the like, or a method of solubilizing sludge with thermophilic bacteria while keeping the sludge in a heated state (Japanese Patent Laid-Open No. 11-90493) ), Various sludge liquefaction methods have been announced, such as a method of solubilizing sludge by the action of ozone (Japanese Patent Laid-Open No. 6-206088). By returning sludge liquefied by these various means back to the biological treatment tank and mineralizing it with microorganisms in the biological treatment tank, the amount of excess sludge generated can be reduced.

しかし、本発明者らが、前記した特開昭57−19719号公報の記載に基づいて、余剰汚泥に超音波を照射して余剰汚泥中の微生物の細胞膜を破壊して可溶化する方法の実験を行ったところ、超音波処理した汚泥を生物処理槽に返送するだけでは、処理水水質の悪化や活性汚泥の流出が起き、エネルギー的にも、先に挙げた特開平6−206088号公報に開示されているオゾンを作用させて汚泥を可溶化する方法と比較して約2倍のエネルギーが必要であることが分かった。即ち、超音波処理による汚泥の可溶化は、投入したエネルギー量に比べて汚泥の液化量が少なく、効率が悪いので、実用化が困難であった。
本発明は、上記のような課題の解決法として考案されたものであり、余剰汚泥の排出量を削減することが可能な有機性廃水の処理技術を提供することを目的とするものである。すなわち、本発明は、超音波を用いた余剰汚泥処理において、余剰汚泥の可溶化をより促進させることのできる方法及び装置を提供することを目的とする。
かかる目的を達成するために鋭意研究を重ねた結果、本発明者らは、余剰汚泥の可溶化処理において、超音波処理と、酸発酵処理、オゾンや過酸化水素或いは酸・アルカリによる化学処理、加温処理の少なくとも一つとを組合わせて用いることにより、汚泥の可溶化(液化)が予想の範囲を超えて格段に向上することを見出し、本発明を完成するに到った。
即ち、本発明は、生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥の処理方法であって、前記余剰汚泥の一部又は全量を、超音波処理と、酸発酵処理、化学処理及び加温処理の少なくとも一つとの組み合わせによって可溶化処理し、可溶化処理された汚泥を生物処理工程に返送することを特徴とする方法に関する。また、本発明は、生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥を処理するための装置であって、前記余剰汚泥の一部又は全量を可溶化処理するための装置と、前記可溶化処理装置で処理された汚泥を生物処理工程へ返送するための配管を具備し、前記可溶化処理装置が、超音波処理装置と、酸発酵処理装置、化学処理装置及び加温処理装置の少なくとも一つとの組み合わせによって構成されることを特徴とする装置に関する。
更に、本発明は、上記の汚泥可溶化手段を備えた有機性廃水の処理方法及び装置にも関する。即ち、本発明の他の態様は、有機性廃水を生物処理槽で生物処理し、生物処理槽から排出される活性汚泥混合液を固液分離して、沈殿汚泥と処理水とを生成させ、前記沈殿汚泥を余剰汚泥としてその一部又は全量を請求項1〜15に規定するいずれかの可溶化処理にかけて処理汚泥を生物処理槽に返送することを特徴とする有機性廃水の処理方法に関する。更に、本発明の他の態様は、有機性廃水を受容して生物処理を行なう生物処理槽、前記生物処理槽から排出される活性汚泥混合液を固液分離して沈殿汚泥と処理水とを生成させる固液分離装置、請求項19〜32に規定するいずれかの汚泥可溶化処理装置、前記固液分離装置から排出される沈殿汚泥の一部又は全量を前記汚泥可溶化処理装置に供給する配管、可溶化処理装置から排出される処理汚泥を生物処理槽に返送する配管を、具備することを特徴とする有機性廃水の処理装置にも関する。
However, based on the description in Japanese Patent Application Laid-Open No. 57-19719, the present inventors have experimented with a method of irradiating surplus sludge with ultrasonic waves to destroy and solubilize cell membranes of microorganisms in the surplus sludge. However, simply returning the ultrasonically treated sludge to the biological treatment tank causes deterioration of the quality of treated water and outflow of activated sludge, and in terms of energy, the above-mentioned JP-A-6-206088 discloses. It has been found that approximately twice as much energy is required as compared to the disclosed method of solubilizing sludge by the action of ozone. That is, the solubilization of sludge by ultrasonic treatment is difficult to put to practical use because the amount of sludge liquefaction is less than the amount of energy input and the efficiency is poor.
The present invention has been devised as a solution to the above-described problems, and an object of the present invention is to provide an organic wastewater treatment technique capable of reducing the amount of excess sludge discharged. That is, an object of the present invention is to provide a method and apparatus that can further promote solubilization of surplus sludge in surplus sludge treatment using ultrasonic waves.
As a result of earnest research to achieve such an object, the present inventors, in solubilization treatment of excess sludge, ultrasonic treatment and acid fermentation treatment, chemical treatment with ozone, hydrogen peroxide or acid / alkali, By using in combination with at least one of the heating treatments, it has been found that solubilization (liquefaction) of sludge is significantly improved beyond the expected range, and the present invention has been completed.
That is, the present invention is a method for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, and a part or all of the surplus sludge is subjected to ultrasonic treatment. Further, the present invention relates to a method characterized by solubilizing by a combination with at least one of acid fermentation treatment, chemical treatment, and heating treatment, and returning the solubilized sludge to a biological treatment step. Further, the present invention is an apparatus for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, and solubilizes part or all of the surplus sludge. An apparatus for processing, and a pipe for returning the sludge processed by the solubilization processing apparatus to the biological treatment process. The solubilization processing apparatus includes an ultrasonic processing apparatus, an acid fermentation processing apparatus, a chemical The present invention relates to an apparatus comprising a combination with at least one of a processing apparatus and a heating processing apparatus.
Furthermore, this invention relates also to the processing method and apparatus of organic wastewater provided with said sludge solubilization means. That is, in another aspect of the present invention, organic wastewater is biologically treated in a biological treatment tank, the activated sludge mixed liquid discharged from the biological treatment tank is subjected to solid-liquid separation, and precipitated sludge and treated water are generated, The present invention relates to a method for treating organic wastewater, characterized in that the treated sludge is returned to a biological treatment tank by applying the solubilized sludge as surplus sludge and subjecting part or all of the amount to a solubilization treatment as defined in claims 1-15. Furthermore, another aspect of the present invention provides a biological treatment tank that receives organic wastewater and performs biological treatment, and an activated sludge mixed liquid discharged from the biological treatment tank is separated into solid and liquid to separate precipitated sludge and treated water. A solid-liquid separation device to be generated, any sludge solubilization treatment device as defined in claims 19 to 32, a part or all of the precipitated sludge discharged from the solid-liquid separation device is supplied to the sludge solubilization treatment device. The present invention also relates to an organic wastewater treatment apparatus comprising a pipe for returning treated sludge discharged from a pipe and a solubilization treatment apparatus to a biological treatment tank.

図1は、有機性廃水の処理プロセスから排出される余剰汚泥を本発明の一態様にかかる方法にしたがって処理する処理フローの概略図である。
図2は、超音波による汚泥処理における超音波強度と汚泥の液化率との関係を示すグラフである。
図3は、本発明によって超音波反応槽に取り付ける超音波ホーンの一形態を示す概略図である。
図4は、有機性廃水の処理プロセスから排出される余剰汚泥を本発明の他の態様にかかる方法にしたがって処理する処理フローの概略図である。
図5は、本発明の一態様にしたがって酸発酵槽内に超音波発振器を設ける場合の構成例を示す概略図である。図5(a)は一つの例を示し、図5(b)は他の例を示す。
図6は、有機性廃水の処理プロセスから排出される余剰汚泥を本発明の他の態様にかかる方法にしたがって処理する処理フローの概略図である。
図7は、有機性廃水の処理プロセスから排出される余剰汚泥を本発明の他の態様にかかる方法にしたがって処理する処理フローの概略図である、
図8は、本発明の他の態様にしたがって加温処理槽内に超音波発振器を設ける場合の構成例を示す概略図である。図8(a)は一つの例を示し、図8(b)は他の例を示す。
図9は、実施例1で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図10は、実施例1における生物処理槽内の汚泥量の変化を示すグラフである。
図11は、比較例1で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図12は、比較例1における生物処理槽内の汚泥量の変化を示すグラフである。
図13は、実施例2で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図14は、実施例2における生物処理槽内の汚泥量の変化を示すグラフである。
図15は、比較例2における生物処理槽内の汚泥量の変化を示すグラフである。
図16は、実施例3で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図17は、実施例3における生物処理槽内の汚泥量の変化を示すグラフである。
図18は、実施例4で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図19は、実施例4における生物処理槽内の汚泥量の変化を示すグラフである。
図20は、実施例5で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図21は、実施例5における生物処理槽内の汚泥量の変化を示すグラフである。
図22は、比較例3で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図23は、比較例3における生物処理槽内の汚泥量の変化を示すグラフである。
図24は、実施例6で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図25は、実施例6における生物処理槽内の汚泥量の変化を示すグラフである。
図26は、実施例8で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
図27は、実施例8における生物処理槽内の汚泥量の変化を示すグラフである。
図28は、実施例10で用いた有機性廃水の生物処理プロセスから発生する余剰汚泥を可溶化処理するシステムの概略図である。
FIG. 1 is a schematic diagram of a treatment flow for treating excess sludge discharged from a treatment process of organic wastewater according to the method according to one embodiment of the present invention.
FIG. 2 is a graph showing the relationship between ultrasonic intensity and sludge liquefaction rate in ultrasonic sludge treatment.
FIG. 3 is a schematic view showing an embodiment of an ultrasonic horn attached to an ultrasonic reaction tank according to the present invention.
FIG. 4 is a schematic diagram of a treatment flow for treating surplus sludge discharged from the treatment process of organic wastewater according to the method according to another aspect of the present invention.
FIG. 5 is a schematic diagram showing a configuration example when an ultrasonic oscillator is provided in an acid fermentation tank according to one embodiment of the present invention. FIG. 5A shows one example, and FIG. 5B shows another example.
FIG. 6 is a schematic view of a treatment flow for treating surplus sludge discharged from the treatment process of organic wastewater according to the method according to another aspect of the present invention.
FIG. 7 is a schematic view of a treatment flow for treating surplus sludge discharged from the treatment process of organic wastewater according to the method according to another aspect of the present invention.
FIG. 8 is a schematic diagram showing a configuration example in the case where an ultrasonic oscillator is provided in a heating treatment tank according to another aspect of the present invention. FIG. 8A shows one example, and FIG. 8B shows another example.
FIG. 9 is a schematic diagram of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 1.
FIG. 10 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 1.
FIG. 11 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Comparative Example 1.
FIG. 12 is a graph showing changes in the amount of sludge in the biological treatment tank in Comparative Example 1.
FIG. 13 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 2.
FIG. 14 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 2.
FIG. 15 is a graph showing changes in the amount of sludge in the biological treatment tank in Comparative Example 2.
FIG. 16 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 3.
FIG. 17 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 3.
FIG. 18 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 4.
FIG. 19 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 4.
FIG. 20 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 5.
FIG. 21 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 5.
FIG. 22 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Comparative Example 3.
FIG. 23 is a graph showing changes in the amount of sludge in the biological treatment tank in Comparative Example 3.
FIG. 24 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 6.
FIG. 25 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 6.
FIG. 26 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 8.
FIG. 27 is a graph showing changes in the amount of sludge in the biological treatment tank in Example 8.
FIG. 28 is a schematic view of a system for solubilizing surplus sludge generated from the biological treatment process of organic wastewater used in Example 10.

以下、本発明の各種形態を図面を参照しながら説明するが、以下の説明は本発明を限定するものではない。
本発明の実施の形態を図面を参照して詳細に説明する。なお、以下の図面において、同一の機能を有するものは同一の符号を付け、その繰り返しの説明は省略する。
図1は、生物処理槽8と固液分離槽9で構成される有機性廃水の生物処理プロセスから排出される余剰汚泥を処理するシステムに、汚泥可溶化手段として超音波反応槽11と酸発酵槽12とをこの順番で設けた本発明の一態様にかかる処理フローの概略図である。有機性廃水1は生物処理槽8に供給される。生物処理槽8では、有機性廃水1中の有機物が活性汚泥により一部無機化され、余剰汚泥が発生する。ここで生物処理槽8として、標準活性汚泥法、嫌気好気法、嫌気無酸素好気法、硝化脱窒法、生物膜法などの当該技術において用いられる任意の生物処理槽が適用可能である。
生物処理槽8から排出される活性汚泥混合液は、固液分離槽9(例えば沈殿池)に供給され、処理水2と沈殿汚泥(余剰汚泥)3に分離される。沈殿汚泥3は、通常返送汚泥として生物処理槽8に返送されるが、本発明においては沈殿汚泥の一部又は全量を可溶化処理にかける。可溶化処理の前段処理として、沈殿汚泥を汚泥濃縮機10に供給して濃縮処理することができる。汚泥濃縮機10では、汚泥が濃縮汚泥4と脱離液7に分離される。脱離液7は生物処理槽8に供給する。一方、濃縮汚泥4は、超音波反応槽11に供給して、超音波処理する。超音波反応槽11には、汚泥に超音波を照射するための超音波発振機若しくは超音波ホーンが配されている。ここで、沈殿汚泥3の蒸発残留物濃度が1%以上ある場合には汚泥濃縮機10を省略して、沈殿汚泥3を直接超音波反応槽11に供給することもできる。
濃縮汚泥4を超音波処理する場合には、汚泥濃度に関係なく液化率が一定なので、超音波反応槽11に供給する濃縮汚泥4の濃度を高くすることで液化量が増加し、効率よく液化汚泥を得ることができる。
図2に、超音波反応槽11における超音波強度と汚泥の液化率との関係を示す。図2は、種々の濃度の汚泥を超音波処理によって液化処理したときの汚泥液化量を示すものであるが、グラフより汚泥濃度が高いほど液化量が高いことが分かる。従って、超音波反応槽11に供給する濃縮汚泥4の濃度を高くすることで液化量が増加し、効率よく液化汚泥を得ることができる。このため、濃縮汚泥4の濃度を1〜10重量%、好ましくは4〜8重量%に濃縮することが好ましい。
また、超音波反応槽11に取り付ける超音波発振機に関しては、消費エネルギー量を被処理液量に対し10〜400kJ/L、超音波ホーン断面積あたりの消費エネルギーを30w/cm以上とすることが望ましい。
また、図3に示すように、超音波反応槽11に取り付ける超音波ホーン13には、被処理汚泥中の超音波波長の長さごとに1波長分の「節」を設けると、超音波の振動エネルギーを物理的により効率よく被処理液に伝達することができるので好ましい。
超音波反応槽11から排出される超音波処理汚泥5は、酸発酵槽12に供給される。酸発酵槽12では、酸発酵反応によって汚泥が液化することに加えて、超音波処理によって汚泥から溶出した酵素により汚泥の液化が進行することが期待できる。酸発酵槽12での汚泥の滞留時間は、超音波処理による汚泥の液化量や有機酸の生成量によって決定することが望ましい。一般に、酸発酵槽での汚泥の滞留日数としては0.2日〜10日の任意の期間を設定することが好ましく、また酸発酵槽内のpHは4.5以上にすることが好ましい。酸発酵槽12での好ましいpH維持のために、NaOH等のアルカリ薬品を酸発酵槽12に添加することもできる。なお、酸発酵工程においては、汚泥を加温しながら酸発酵を進行させると汚泥の液化がより進むので好ましい。この場合の加温の温度は、30〜40℃が好適である。
また、酸発酵槽12には、沈殿汚泥3の一部を供給することが可能である。超音波処理汚泥5と沈殿汚泥3とを混合することで、超音波処理汚泥5から溶出した酵素による汚泥の液化が期待できる。また、酸発酵槽12に、有機性廃水1の一部又は全部を供給することも可能である。有機性廃水1を酸発酵槽12に供給することで、有機性廃水1中の有機物が酸発酵されて、生物処理されやすくなる効果が期待できる。なお、排水量を調整するための調整槽が設けられている場合には、調整槽が嫌気状態となって酸発酵槽として利用できることもある。
酸発酵槽12から排出される酸発酵汚泥6は、生物処理槽8に返送される。循環式の硝化脱窒法などのように生物処理槽に脱窒槽が含まれる場合には、酸発酵汚泥6に含まれる溶解性の有機物が脱窒反応の水素供与体として利用できるので、酸発酵汚泥6を脱窒槽に供給することは、有効な有機性廃水の処理方法となる。
また、本発明の他の形態として、図4は、有機性廃水の生物処理プロセスから排出される余剰汚泥を処理するシステムに汚泥可溶化手段として酸発酵槽と超音波反応槽とをこの順番で設けた本発明の他の態様にかかる処理フローの概略図である。有機性廃水1は生物処理槽8に供給され、有機性廃水1中の有機物が活性汚泥により無機化される。生物処理槽8からの活性汚泥混合液は固液分離槽9に供給され、処理水2と沈殿汚泥(余剰汚泥)3に分離される。沈殿汚泥3の一部または全量が酸発酵槽12に供給され、酸発酵処理されて酸発酵汚泥6となる。酸発酵槽12は、単純なタンクでよく、酸発酵槽12での汚泥の滞留時間は液化反応の進行度合いに応じて決定すると良い。なお、必要に応じて酸発酵槽12の前に汚泥濃縮機を設け、濃縮した汚泥を酸発酵槽12に供給することも可能である。
酸発酵槽12から排出される酸発酵汚泥6は、次に超音波反応槽11に供給して超音波処理し、得られた超音波処理汚泥5を、生物処理槽8に返送する。循環式の硝化脱窒法など脱窒槽がある場合は、超音波処理汚泥5に含まれる溶解性の有機物が脱窒反応の水素供与体として利用できるので、超音波処理汚泥5を脱窒槽に供給することは、有効な処理方法となる。
また、超音波発振器を酸発酵槽内に取り付けて、酸発酵槽内で汚泥の超音波処理と酸発酵処理とを同時に行なうこともできる。酸発酵槽内に超音波発振機を取り付けた本発明の他の形態にかかる汚泥可溶化装置の構成例を図5に示す。図5において、14は超音波発振器、15は攪拌機である。図5(a)に示すように酸発酵槽12内に超音波発振器14を挿入するように配置してもよく、或いは図5(b)に示すように酸発酵槽12の底部に超音波発振器14を取り付けてもよい。
超音波発振器14を備えた酸発酵槽12から排出される超音波・酸発酵処理汚泥31は生物処理槽8に供給される。循環式の硝化脱窒法など脱窒槽がある場合は、超音波・酸発酵処理汚泥31に含まれる溶解性の有機物が脱窒反応の水素供与体として利用できるので、超音波・酸発酵処理汚泥31を脱窒槽に供給することは、有効な処理方法となる。
なお、上記のように汚泥の可溶化手段として超音波処理と酸発酵処理とを組合わせて行なう場合には、酸発酵槽12での酸化還元電位(ORP)を測定して、これが−100mV以下、好ましくは−200mV〜−400mVになるように酸発酵槽での条件を制御すると、汚泥の過剰な腐敗を抑制すると共に、一部汚泥が生存した状態で汚泥の液化が進むので好ましい。この手段としては、酸発酵槽12内に酸化還元電位の測定器を配置して、酸化還元電位を測定しながら、これが−100mV以下、好ましくは−200mV〜−400mVになるように酸発酵槽12での汚泥の貯留時間を定めればよい。
また、酸発酵槽での酸化還元電位を調整する方法として、有機性廃水(原水)1の一部を酸発酵槽12に供給してもよい。更に、図1に示すように処理フローの上流側から超音波処理槽11−酸発酵槽12の順に配置されている場合には、原水1の一部を酸発酵槽の上流の超音波処理槽11に供給したり、或いは、酸発酵処理槽12から排出される酸発酵処理汚泥6の一部を超音波処理槽11に返送してもよい。更には、図4に示すように処理フローの上流側から酸発酵槽12−超音波処理槽11の順に配置されている場合には、超音波処理汚泥5の一部を酸発酵槽12に返送してもよい。原水1や超音波処理汚泥5、更には酸発酵処理汚泥6には、溶解性の有機物が含まれ、これが酸発酵を促進させ、ORPを低下させるのに有効だからである。なお、酸発酵は生物反応であるので、酸発酵槽12は、加温したり、或いは断熱構造にしておくと、酸発酵を進めるために有効な手段となるので好ましい。
また、図6には、本発明の他の態様として、有機性廃水の生物処理プロセスから排出される余剰汚泥を処理するシステムに、汚泥可溶化手段として超音波反応工程と、化学的処理工程とを設けた本発明による処理フローの概略図を示す。
有機性廃水1は生物処理槽8に供給されて、有機性廃水1中の有機物が活性汚泥により無機化される。生物処理槽8としては、標準活性汚泥法や嫌気好気法、嫌気無酸素好気法,硝化脱窒法、生物膜法など当該技術において用いられる任意の生物処理槽が適用可能である。
生物処理槽8から排出される活性汚泥混合液は、固液分離槽9(例えば沈殿池)に供給され、処理水2と沈殿汚泥(余剰汚泥)3に分離される。沈殿汚泥3の一部又は全量が汚泥濃縮機10に供給され、濃縮汚泥4と脱離液7に分離される。なお、沈殿汚泥3の汚泥濃度が1重量%以上ある場合には汚泥濃縮機10を省略し、沈殿汚泥3を直接、超音波反応槽11に供給することも可能である。脱離液7は生物処理槽8に返送されるが、水質が良好ならそのまま放流することもできる。濃縮汚泥4は、超音波反応槽11に供給して、超音波処理する。
超音波反応槽11から流出した超音波処理汚泥5は、汚泥液化槽13に供給される。汚泥液化槽13では、化学的処理として、オゾン、過酸化水素などの酸化剤、アルカリ剤の添加により汚泥の液化処理が行われる。超音波処理と化学処理を組み合わせることで汚泥の液化率が格段に向上する。この理由としては、超音波処理で汚泥が微細化するので、化学的処理において汚泥と薬品の接触がより効率的に起きることが考えられる。
汚泥液化槽13から流出した化学処理汚泥41は、生物処理槽8に返送される。この時、化学処理汚泥41を、一旦、貯留槽で一定時間嫌気状態で貯留して酸発酵反応を進行させてのちに、生物処理槽8に返送することも可能である。このように超音波処理及び化学処理を行なった汚泥に対して更に酸発酵処理を行なうことで、汚泥の液化が更に進行する効果が期待できる。酸発酵では汚泥の液化がより進むため、液化量を増やす効果が期待できる。なお、有機性廃水処理装置によっては、有機性廃水1の水量変動を調整するため、生物処理槽8の前段に調整槽が設けられていることがある。このような処理系では調整槽を貯留槽の代わりとして利用することが可能である。この場合には、原水と処理汚泥を嫌気状態に保つことにより、超音波処理汚泥5のほかに有機性廃水1中の有機物の酸発酵も起こることが期待でき、有効な有機性廃水の処理方法となる。
循環式の硝化脱窒法などのように生物処理槽に脱窒槽が含まれる場合には、化学処理汚泥41に含まれる溶解性の有機物を脱窒反応の水素供与体として利用できるので、化学処理汚泥41を脱窒槽に供給することは有効な処理方法となる。
なお、図6に示すシステムにおいて、濃縮汚泥4をまず化学的処理13にかけて、次に超音波処理11にかけるようにしてもよい。
更に、本発明の他の態様として、図7に、有機性廃水の生物処理プロセスから排出される余剰汚泥を処理するシステムに汚泥可溶化手段として加温工程と超音波反応工程とをこの順番で設けた本発明にかかる処理フローの概略図を示す。
有機性廃水1は、生物処理槽8に供給されて、有機性廃水1中の有機物が活性汚泥により無機化される。ここで、生物処理槽8としては、標準活性汚泥法や嫌気好気法、嫌気無酸素好気法、硝化脱窒法、生物膜法など当該技術において用いられる任意の生物処理槽が適用可能である。
生物処理槽8からの活性汚泥混合液は、固液分離槽9に供給され、処理水2と沈殿汚泥(余剰汚泥)3に分離される。沈殿汚泥3は、一部又は全量が汚泥濃縮機10に供給され、濃縮汚泥4と脱離液7に分離される。なお、沈殿汚泥3の汚泥濃度が1重量%以上ある場合には汚泥濃縮機10を省略し、沈殿汚泥3を直接、加温処理槽17に供給することも可能である。脱離液7は生物処理槽8に返送されるが、水質が良好ならそのまま放流することもできる。濃縮汚泥4は、加温処理槽17に供給して、加温による汚泥の可溶化処理が行なわれる。加温処理槽17における槽内の温度は、40℃以上であれば汚泥の可溶化が促進されるが、加熱に必要なエネルギーを考慮すると50〜90℃が現実的である。加温処理槽17は、加温ができれば熱交換器のように配管の一部として設置することも可能である。また、熱源が豊富な工場などでは、専用のボイラーを設けなくても廃熱を利用できるのでエネルギーをより節約することができる。加温処理槽17から排出される加温処理汚泥18は、次に超音波反応槽11に供給され、超音波処理される。
超音波反応槽11から排出される超音波処理汚泥5は、生物処理槽8に返送される。この際、超音波処理汚泥5を、貯留槽で一定時間嫌気状態で貯留したのちに生物処理槽8に供給することも可能である。このように嫌気状態に維持した貯留槽に超音波処理汚泥5を貯留すると、酸発酵による汚泥の更なる液化が進行することが期待できる。有機性廃水処理装置によっては、有機性廃水1の水量変動を調整するため、生物処理槽8の前段に調整槽が設けられていることがある。このような処理系では、調整槽を貯留槽の代わりとして利用することが可能である。この際、原水と処理汚泥を嫌気状態に保持することにより、超音波処理汚泥5のほかに有機性廃水1中の有機物の酸発酵が起きることが期待でき、有効な処理方法となる。
循環式の硝化脱窒法などのように生物処理槽8に脱窒槽が含まれる場合には、超音波処理汚泥5に含まれる溶解性の有機物が、脱窒反応の水素供与体として利用できるので、超音波処理汚泥5を脱窒槽に供給することは、有効な処理方法となる。
なお、図7に示すシステムにおいても、汚泥可溶化手段の構成を逆にして、即ち、濃縮汚泥4をまず超音波処理11にかけて、次に加温処理17にかけるようにしてもよい。
更に、超音波発振器を加温処理槽17内に取り付けて、加温処理槽内で汚泥の超音波処理と加温処理とを同時に行なうこともできる。加温処理槽17内に超音波発振機を取り付けた本発明の他の形態にかかる汚泥可溶化装置の構成例を図8に示す。図8において、14は超音波発振器、15は攪拌機である。図8(a)に示すように加温処理槽17内に超音波発振器14を挿入するように配置してもよく、或いは図8(b)に示すように加温処理槽17の底部に超音波発振器14を取り付けてもよい。
超音波発振器14を備えた加温処理槽17から排出される超音波・加温処理汚泥32は生物処理槽8に供給される。循環式の硝化脱窒法など脱窒槽がある場合は、超音波・加温処理汚泥32に含まれる溶解性の有機物が脱窒反応の水素供与体として利用できるので、超音波・加温処理汚泥32を脱窒槽に供給することは、有効な処理方法となる。
本発明の各種形態は、以下の通りである。
1.生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥の処理方法であって、前記余剰汚泥の一部又は全量を、超音波処理と、酸発酵処理、化学処理及び加温処理の少なくとも一つとの組み合わせによって可溶化処理し、可溶化処理された汚泥を生物処理工程に返送することを特徴とする方法。
2.汚泥の化学処理が、オゾン、過酸化水素、酸化剤及びアルカリ剤のいずれかによって汚泥を処理するものである上記第1項に記載の方法。
3.前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
4.前記余剰汚泥の一部又は全量を酸発酵処理し、酸発酵処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
5.前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に化学処理して、化学処理された汚泥を生物処理工程に返送する上記第1項又は第2項に記載の方法。
6.前記余剰汚泥の一部又は全量を化学処理し、化学処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する上記第1項又は第2項に記載の方法。
7.前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に加温処理し、加温処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
8.前記余剰汚泥の一部又は全量を加温処理し、加温処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
9.前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に加温処理し、加温処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
10.前記余剰汚泥の一部又は全量を加温処理し、加温処理汚泥を次に超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
11.前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に化学処理し、化学処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する上記第1項又は第2項に記載の方法。
12.前記余剰汚泥の一部又は全量を化学処理し、化学処理汚泥を次に超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する上記第1項又は第2項に記載の方法。
13.前記余剰汚泥の一部又は全量を、超音波発信機を備えた酸発酵槽において酸発酵しながら超音波処理して、処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
14.前記余剰汚泥の一部又は全量を、超音波発信機を備えた加温槽において加温しながら超音波処理して、処理された汚泥を生物処理工程に返送する上記第1項に記載の方法。
15.酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、酸発酵処理での汚泥の水力学的滞留時間を制御する上記第1項,第2項,第3項,第4項,第9項,第10項,第11項,第12項又は第13項のいずれかに記載の方法。
16.酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、有機性廃水の一部を直接酸発酵処理に供給する上記第1項,第2項,第3項,第4項,第9項,第10項,第11項,第12項又は第13項のいずれかに記載の方法。
17.酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、酸発酵処理された汚泥の一部を超音波処理に返送する上記第1項,第2項,第3項,第9項,第10項又は第12項のいずれかに記載の方法。
18.酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、超音波処理された汚泥の一部を酸発酵処理に返送する上記第1項,第2項又は第4項のいずれかに記載の方法。
19.余剰汚泥の一部又は全量を、汚泥濃度で1〜10重量%に濃縮し、濃縮した汚泥を前記可溶化処理する上記第1項〜第18項のいずれかに記載の方法。
20.有機性廃水を生物処理槽で生物処理し、生物処理槽から排出される活性汚泥混合液を固液分離して、沈殿汚泥と処理水とを生成させ、前記沈殿汚泥を余剰汚泥としてその一部又は全量を上記第1項〜第19項のいずれかに規定する可溶化処理にかけて処理汚泥を生物処理槽に返送することを特徴とする有機性廃水の処理方法。
21.有機性廃水を生物処理槽で生物処理し、生物処理槽から排出される活性汚泥混合液を固液分離して、沈殿汚泥と処理水とを生成させ、前記沈殿汚泥を余剰汚泥としてその一部又は全量を汚泥濃度で1〜10重量%に濃縮し、濃縮した汚泥を上記第1項〜第19項のいずれかに規定する可溶化処理にかけて処理汚泥を生物処理槽に返送することを特徴とする有機性廃水の処理方法。
22.生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥を処理するための装置であって、前記余剰汚泥の一部又は全量を可溶化処理するための装置と、前記可溶化処理装置で処理された汚泥を生物処理工程へ返送するための配管を具備し、前記可溶化処理装置が、超音波処理装置と、酸発酵処理装置、化学処理装置及び加温処理装置の少なくとも一つとの組み合わせによって構成されることを特徴とする装置。
23.汚泥の可溶化処理装置が、オゾン、過酸化水素、酸化剤及びアルカリ剤のいずれかを用いる化学処理装置である上記第22項に記載の装置。
24.汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される上記第22項に記載の装置。
25.汚泥の可溶化処理装置が、汚泥を酸発酵処理する酸発酵装置と、酸発酵処理汚泥を超音波処理する超音波処理装置とにより構成される上記第22項に記載の装置。
26.汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を化学処理する化学処理装置とにより構成される上記第22項又は第23項に記載の装置。
27.汚泥の可溶化処理装置が、汚泥を化学処理する化学処理装置と、化学処理汚泥を超音波処理する超音波処理装置とにより構成される上記第22項又は第23項に記載の装置。
28.汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を加温処理する加温処理装置とにより構成される上記第22項に記載の装置。
26.汚泥の可溶化処理装置が、汚泥を加温処理する加温処理装置と、加温処理汚泥を超音波処理する超音波処理装置とにより構成される上記第22項に記載の装置。
30.汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を加温処理する加温処理装置と、加温処理汚泥を酸発酵処理する酸発酵装置とにより構成される上記第22項に記載の装置。
31.汚泥の可溶化処理装置が、汚泥を加温処理する加温処理装置と、加温処理汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される上記第22項に記載の装置。
32.汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を化学処理する化学処理装置と、化学処理汚泥を酸発酵処理する酸発酵装置とにより構成される上記第22項又は第23項に記載の装置。
33.汚泥の可溶化処理装置が、汚泥を化学処理する化学処理装置と、化学処理汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される上記第22項又は第23項に記載の装置。
34.汚泥の可溶化処理装置が、超音波発信機を備えた酸発酵槽により構成される上記第22項に記載の装置。
35.汚泥の可溶化処理装置が、超音波発信機を備えた加温槽により構成される上記第22項に記載の装置。
36.余剰汚泥の一部又は全量を受容して汚泥を濃縮する濃縮装置と、濃縮装置から排出される濃縮汚泥を前記可溶化処理装置に供給する配管とを更に具備する上記第22項〜第35項のいずれかに記載の装置。
37.有機性廃水を受容して生物処理を行なう生物処理槽、前記生物処理槽から排出される活性汚泥混合液を固液分離して沈殿汚泥と処理水とを生成させる固液分離装置、上記第22項〜第36項のいずれかに規定する汚泥可溶化処理装置、前記固液分離装置から排出される沈殿汚泥の一部又は全量を前記汚泥可溶化処理装置に供給する配管、可溶化処理装置から排出される処理汚泥を生物処理槽に返送する配管を、具備することを特徴とする有機性廃水の処理装置。
38.有機性廃水を受容して生物処理を行なう生物処理槽、前記生物処理槽から排出される活性汚泥混合液を固液分離して沈殿汚泥と処理水とを生成させる固液分離装置、前記固液分離装置から排出される沈殿汚泥の一部又は全量を受容して汚泥を濃縮する濃縮装置、上記第22項〜第36項のいずれかに規定する汚泥可溶化処理装置、濃縮装置から排出される濃縮汚泥を前記可溶化処理装置に供給する配管、可溶化処理装置から排出される処理汚泥を生物処理槽に返送する配管、を具備することを特徴とする有機性廃水の処理装置。
以下の実施例により、本発明を更に具体的に説明する。以下の実施例は、本発明を具現化するための幾つかの具体例を示したものであり、本発明はこれらの記載に限定されるものではない。
Hereinafter, various forms of the present invention will be described with reference to the drawings. However, the following description does not limit the present invention.
Embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the following drawings, what has the same function attaches | subjects the same code | symbol, and the repeated description is abbreviate | omitted.
FIG. 1 shows an ultrasonic reaction tank 11 and acid fermentation as sludge solubilization means in a system for treating surplus sludge discharged from a biological treatment process of organic wastewater composed of a biological treatment tank 8 and a solid-liquid separation tank 9. It is the schematic of the processing flow concerning 1 aspect of this invention which provided the tank 12 in this order. The organic waste water 1 is supplied to the biological treatment tank 8. In the biological treatment tank 8, the organic matter in the organic waste water 1 is partially mineralized by activated sludge, and surplus sludge is generated. Here, as the biological treatment tank 8, any biological treatment tank used in the art such as a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic aerobic method, a nitrification denitrification method, and a biofilm method can be applied.
The activated sludge mixed liquid discharged from the biological treatment tank 8 is supplied to a solid-liquid separation tank 9 (for example, a sedimentation basin) and separated into treated water 2 and precipitated sludge (excess sludge) 3. The precipitated sludge 3 is usually returned to the biological treatment tank 8 as a return sludge. In the present invention, a part or all of the precipitated sludge is subjected to a solubilization treatment. As the pre-treatment of the solubilization treatment, the precipitated sludge can be supplied to the sludge concentrator 10 and concentrated. In the sludge concentrator 10, the sludge is separated into the concentrated sludge 4 and the detachment liquid 7. The detachment liquid 7 is supplied to the biological treatment tank 8. On the other hand, the concentrated sludge 4 is supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment. The ultrasonic reaction tank 11 is provided with an ultrasonic oscillator or an ultrasonic horn for irradiating the sludge with ultrasonic waves. Here, when the concentration of evaporation residue of the precipitated sludge 3 is 1% or more, the sludge concentrator 10 can be omitted and the precipitated sludge 3 can be directly supplied to the ultrasonic reaction tank 11.
When ultrasonically treating the concentrated sludge 4, the liquefaction rate is constant regardless of the sludge concentration. Therefore, increasing the concentration of the concentrated sludge 4 supplied to the ultrasonic reaction tank 11 increases the amount of liquefaction and liquefies efficiently. Sludge can be obtained.
In FIG. 2, the relationship between the ultrasonic intensity | strength in the ultrasonic reaction tank 11 and the liquefaction rate of sludge is shown. FIG. 2 shows the sludge liquefaction amount when sludge having various concentrations is liquefied by ultrasonic treatment. From the graph, it can be seen that the liquefaction amount is higher as the sludge concentration is higher. Therefore, by increasing the concentration of the concentrated sludge 4 supplied to the ultrasonic reaction tank 11, the amount of liquefaction increases, and the liquefied sludge can be obtained efficiently. For this reason, it is preferable to concentrate the concentration of the concentrated sludge 4 to 1 to 10% by weight, preferably 4 to 8% by weight.
Moreover, regarding the ultrasonic oscillator attached to the ultrasonic reaction tank 11, the amount of energy consumption is 10 to 400 kJ / L with respect to the amount of liquid to be processed, and the energy consumption per ultrasonic horn cross-sectional area is 30 w / cm 2 or more. Is desirable.
In addition, as shown in FIG. 3, the ultrasonic horn 13 attached to the ultrasonic reaction tank 11 is provided with “nodes” for one wavelength for each ultrasonic wavelength length in the treated sludge. It is preferable because vibration energy can be physically and efficiently transmitted to the liquid to be treated.
The sonicated sludge 5 discharged from the ultrasonic reaction tank 11 is supplied to the acid fermentation tank 12. In the acid fermenter 12, in addition to liquefaction of sludge by an acid fermentation reaction, it can be expected that liquefaction of sludge proceeds by an enzyme eluted from the sludge by ultrasonic treatment. The sludge residence time in the acid fermentation tank 12 is desirably determined by the amount of sludge liquefied by ultrasonic treatment and the amount of organic acid produced. Generally, it is preferable to set an arbitrary period of 0.2 days to 10 days as the sludge residence days in the acid fermentation tank, and the pH in the acid fermentation tank is preferably 4.5 or more. In order to maintain a preferable pH in the acid fermenter 12, alkaline chemicals such as NaOH can be added to the acid fermenter 12. In the acid fermentation process, it is preferable to advance the acid fermentation while heating the sludge because the liquefaction of the sludge further proceeds. In this case, the heating temperature is preferably 30 to 40 ° C.
Further, it is possible to supply a part of the precipitated sludge 3 to the acid fermentation tank 12. By mixing the sonicated sludge 5 and the precipitated sludge 3, liquefaction of the sludge by the enzyme eluted from the sonicated sludge 5 can be expected. It is also possible to supply part or all of the organic waste water 1 to the acid fermentation tank 12. By supplying the organic waste water 1 to the acid fermenter 12, the organic matter in the organic waste water 1 is acid-fermented, and an effect of facilitating biological treatment can be expected. In addition, when the adjustment tank for adjusting the amount of drainage is provided, the adjustment tank may become anaerobic and can be utilized as an acid fermentation tank.
The acid fermentation sludge 6 discharged from the acid fermentation tank 12 is returned to the biological treatment tank 8. When a denitrification tank is included in the biological treatment tank, such as in a circulatory nitrification denitrification method, the soluble organic matter contained in the acid fermentation sludge 6 can be used as a hydrogen donor for the denitrification reaction. Supplying 6 to the denitrification tank is an effective method for treating organic wastewater.
As another form of the present invention, FIG. 4 shows an acid fermentation tank and an ultrasonic reaction tank in this order as sludge solubilization means in a system for treating surplus sludge discharged from a biological treatment process of organic wastewater. It is the schematic of the processing flow concerning the other aspect of this invention provided. The organic wastewater 1 is supplied to the biological treatment tank 8, and the organic matter in the organic wastewater 1 is mineralized by activated sludge. The activated sludge mixed liquid from the biological treatment tank 8 is supplied to the solid-liquid separation tank 9 and separated into treated water 2 and precipitated sludge (excess sludge) 3. Part or all of the precipitated sludge 3 is supplied to the acid fermentation tank 12 and subjected to an acid fermentation treatment to become the acid fermentation sludge 6. The acid fermenter 12 may be a simple tank, and the sludge residence time in the acid fermenter 12 may be determined according to the progress of the liquefaction reaction. If necessary, a sludge concentrator may be provided in front of the acid fermentation tank 12 to supply the concentrated sludge to the acid fermentation tank 12.
The acid fermentation sludge 6 discharged from the acid fermentation tank 12 is then supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment, and the obtained ultrasonic treatment sludge 5 is returned to the biological treatment tank 8. When there is a denitrification tank such as a circulatory nitrification denitrification method, the soluble organic matter contained in the ultrasonic treatment sludge 5 can be used as a hydrogen donor for the denitrification reaction, so the ultrasonic treatment sludge 5 is supplied to the denitrification tank. This is an effective processing method.
In addition, an ultrasonic oscillator can be attached in the acid fermentation tank, and the ultrasonic treatment of the sludge and the acid fermentation process can be simultaneously performed in the acid fermentation tank. The structural example of the sludge solubilization apparatus concerning the other form of this invention which attached the ultrasonic oscillator in the acid fermenter is shown in FIG. In FIG. 5, 14 is an ultrasonic oscillator, and 15 is a stirrer. As shown in FIG. 5 (a), an ultrasonic oscillator 14 may be inserted into the acid fermentation tank 12, or an ultrasonic oscillator is installed at the bottom of the acid fermentation tank 12 as shown in FIG. 5 (b). 14 may be attached.
The ultrasonic / acid fermentation treatment sludge 31 discharged from the acid fermentation tank 12 equipped with the ultrasonic oscillator 14 is supplied to the biological treatment tank 8. When there is a denitrification tank such as a circulatory nitrification denitrification method, the soluble organic matter contained in the ultrasonic / acid fermentation treated sludge 31 can be used as a hydrogen donor for the denitrification reaction. Supplying to the denitrification tank is an effective treatment method.
In the case where ultrasonic treatment and acid fermentation treatment are performed in combination as a sludge solubilization means as described above, the oxidation-reduction potential (ORP) in the acid fermentation tank 12 is measured, and this is -100 mV or less. Preferably, it is preferable to control the conditions in the acid fermenter so as to be −200 mV to −400 mV, since excessive rot of the sludge is suppressed and liquefaction of the sludge proceeds while a portion of the sludge is alive. As this means, a redox potential measuring device is arranged in the acid fermenter 12, and while measuring the redox potential, the acid fermenter 12 is -100 mV or less, preferably -200 mV to -400 mV. What is necessary is just to set the storage time of sludge.
Further, as a method for adjusting the oxidation-reduction potential in the acid fermentation tank, a part of the organic waste water (raw water) 1 may be supplied to the acid fermentation tank 12. Furthermore, when it arrange | positions in order of the ultrasonic treatment tank 11-acid fermentation tank 12 from the upstream of a process flow as shown in FIG. 1, a part of raw | natural water 1 is an ultrasonic treatment tank upstream of an acid fermentation tank. 11 or a part of the acid fermentation treatment sludge 6 discharged from the acid fermentation treatment tank 12 may be returned to the ultrasonic treatment tank 11. Furthermore, when it arrange | positions in order of the acid fermentation tank 12-sonication tank 11 from the upstream of a process flow as shown in FIG. 4, a part of ultrasonication sludge 5 is returned to the acid fermentation tank 12. May be. This is because the raw water 1, the ultrasonically treated sludge 5, and further the acid fermentation treated sludge 6 contain soluble organic substances, which are effective for promoting acid fermentation and reducing ORP. In addition, since acid fermentation is a biological reaction, it is preferable to heat the acid fermenter 12 or to have a heat insulating structure because it becomes an effective means for proceeding acid fermentation.
Further, in FIG. 6, as another aspect of the present invention, an ultrasonic reaction process as a sludge solubilization means, a chemical treatment process, and a system for treating surplus sludge discharged from a biological treatment process of organic wastewater, The schematic of the processing flow by this invention provided with is shown.
The organic wastewater 1 is supplied to the biological treatment tank 8, and the organic matter in the organic wastewater 1 is mineralized by activated sludge. As the biological treatment tank 8, any biological treatment tank used in the art such as a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic aerobic method, a nitrification denitrification method, or a biofilm method can be applied.
The activated sludge mixed liquid discharged from the biological treatment tank 8 is supplied to a solid-liquid separation tank 9 (for example, a sedimentation basin) and separated into treated water 2 and precipitated sludge (excess sludge) 3. Part or all of the precipitated sludge 3 is supplied to the sludge concentrator 10 and separated into the concentrated sludge 4 and the desorbed liquid 7. In addition, when the sludge density | concentration of the sedimentation sludge 3 is 1 weight% or more, it is also possible to abbreviate | omit the sludge concentration machine 10 and to supply the sedimentation sludge 3 to the ultrasonic reaction tank 11 directly. The detachment liquid 7 is returned to the biological treatment tank 8, but can be discharged as it is if the water quality is good. The concentrated sludge 4 is supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment.
The ultrasonically treated sludge 5 flowing out from the ultrasonic reaction tank 11 is supplied to the sludge liquefaction tank 13. In the sludge liquefaction tank 13, as a chemical treatment, sludge liquefaction treatment is performed by adding an oxidizing agent such as ozone or hydrogen peroxide, or an alkali agent. By combining ultrasonic treatment and chemical treatment, the sludge liquefaction rate is significantly improved. The reason for this is that since sludge is refined by ultrasonic treatment, the contact between the sludge and the chemical occurs more efficiently in the chemical treatment.
The chemically treated sludge 41 flowing out from the sludge liquefaction tank 13 is returned to the biological treatment tank 8. At this time, the chemically treated sludge 41 can be temporarily stored in an anaerobic state in the storage tank for a certain period of time to advance the acid fermentation reaction, and then returned to the biological treatment tank 8. The effect of further liquefaction of sludge can be expected by further performing acid fermentation treatment on the sludge subjected to ultrasonic treatment and chemical treatment. In acid fermentation, the liquefaction of sludge further proceeds, so the effect of increasing the amount of liquefaction can be expected. Depending on the organic wastewater treatment apparatus, an adjustment tank may be provided in front of the biological treatment tank 8 in order to adjust the fluctuation of the amount of the organic wastewater 1. In such a processing system, the adjustment tank can be used in place of the storage tank. In this case, by maintaining the raw water and the treated sludge in an anaerobic state, it can be expected that acid fermentation of organic matter in the organic wastewater 1 will occur in addition to the ultrasonic treated sludge 5, and an effective method for treating organic wastewater. It becomes.
When the biological treatment tank includes a denitrification tank such as a circulatory nitrification denitrification method, the soluble organic matter contained in the chemical treatment sludge 41 can be used as a hydrogen donor for the denitrification reaction. Supplying 41 to the denitrification tank is an effective treatment method.
In the system shown in FIG. 6, the concentrated sludge 4 may be first subjected to the chemical treatment 13 and then to the ultrasonic treatment 11.
Furthermore, as another aspect of the present invention, in FIG. 7, a heating process and an ultrasonic reaction process are performed in this order as a sludge solubilization means in a system for treating surplus sludge discharged from a biological treatment process of organic wastewater. The schematic of the processing flow concerning the provided this invention is shown.
The organic wastewater 1 is supplied to the biological treatment tank 8, and the organic matter in the organic wastewater 1 is mineralized by activated sludge. Here, as the biological treatment tank 8, any biological treatment tank used in the art such as a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic aerobic method, a nitrification denitrification method, or a biofilm method can be applied. .
The activated sludge mixed liquid from the biological treatment tank 8 is supplied to the solid-liquid separation tank 9 and separated into treated water 2 and precipitated sludge (excess sludge) 3. Part or all of the precipitated sludge 3 is supplied to the sludge concentrator 10 and separated into the concentrated sludge 4 and the desorbed liquid 7. In addition, when the sludge density | concentration of the sedimentation sludge 3 is 1 weight% or more, it is also possible to abbreviate | omit the sludge concentration machine 10 and to supply the sedimentation sludge 3 directly to the heating process tank 17. FIG. The detachment liquid 7 is returned to the biological treatment tank 8, but can be discharged as it is if the water quality is good. The concentrated sludge 4 is supplied to the heating treatment tank 17 and the sludge solubilization treatment is performed by heating. If the temperature in the heating treatment tank 17 is 40 ° C. or higher, solubilization of sludge is promoted, but 50 to 90 ° C. is realistic considering the energy required for heating. The heating treatment tank 17 can be installed as a part of piping like a heat exchanger if it can be heated. In factories with abundant heat sources, energy can be saved because waste heat can be used without installing a dedicated boiler. The warming sludge 18 discharged from the warming treatment tank 17 is then supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment.
The sonicated sludge 5 discharged from the ultrasonic reaction tank 11 is returned to the biological treatment tank 8. At this time, the ultrasonic treatment sludge 5 can be supplied to the biological treatment tank 8 after being stored in an anaerobic state for a certain time in the storage tank. Thus, if the ultrasonic treatment sludge 5 is stored in the storage tank maintained in an anaerobic state, it can be expected that further liquefaction of the sludge by acid fermentation proceeds. Depending on the organic wastewater treatment apparatus, an adjustment tank may be provided in front of the biological treatment tank 8 in order to adjust the fluctuation of the amount of the organic wastewater 1. In such a processing system, the adjustment tank can be used as a substitute for the storage tank. At this time, by maintaining the raw water and the treated sludge in an anaerobic state, it can be expected that acid fermentation of the organic matter in the organic wastewater 1 in addition to the ultrasonic treated sludge 5 occurs, and this is an effective treatment method.
When the biological treatment tank 8 includes a denitrification tank such as a circulatory nitrification denitrification method, the soluble organic matter contained in the ultrasonic treatment sludge 5 can be used as a hydrogen donor for the denitrification reaction. Supplying the ultrasonic treatment sludge 5 to the denitrification tank is an effective treatment method.
In the system shown in FIG. 7 as well, the configuration of the sludge solubilizing means may be reversed, that is, the concentrated sludge 4 may be first subjected to the ultrasonic treatment 11 and then to the heating treatment 17.
Furthermore, an ultrasonic oscillator can be attached in the heating treatment tank 17, and the ultrasonic treatment and heating treatment of sludge can be performed simultaneously in the heating treatment tank. FIG. 8 shows a configuration example of a sludge solubilizer according to another embodiment of the present invention in which an ultrasonic oscillator is attached in the heating treatment tank 17. In FIG. 8, 14 is an ultrasonic oscillator, and 15 is a stirrer. As shown in FIG. 8 (a), the ultrasonic oscillator 14 may be inserted into the heating treatment tank 17, or as shown in FIG. A sound wave oscillator 14 may be attached.
The ultrasonic / heat treatment sludge 32 discharged from the heat treatment tank 17 provided with the ultrasonic oscillator 14 is supplied to the biological treatment tank 8. When there is a denitrification tank such as a circulatory nitrification denitrification method, the soluble organic matter contained in the ultrasonic / heat treatment sludge 32 can be used as a hydrogen donor for the denitrification reaction. Supplying to the denitrification tank is an effective treatment method.
Various aspects of the present invention are as follows.
1. A method for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, wherein a part or all of the surplus sludge is subjected to ultrasonic treatment, acid fermentation treatment, chemical A method comprising solubilizing by combination with at least one of treatment and heating treatment, and returning the solubilized sludge to the biological treatment step.
2. 2. The method according to item 1 above, wherein the sludge is treated with ozone, hydrogen peroxide, an oxidizing agent, or an alkaline agent.
3. The method according to claim 1, wherein a part or all of the surplus sludge is sonicated, the sonicated sludge is then subjected to acid fermentation, and the acid-fermented sludge is returned to the biological treatment step.
4). The method according to claim 1, wherein a part or all of the excess sludge is subjected to an acid fermentation treatment, the acid fermentation treatment sludge is then subjected to ultrasonic treatment, and the ultrasonically treated sludge is returned to the biological treatment step.
5. The method according to claim 1 or 2, wherein a part or all of the excess sludge is sonicated, the sonicated sludge is then chemically treated, and the chemically treated sludge is returned to the biological treatment step. .
6). The method according to claim 1 or 2, wherein a part or all of the excess sludge is chemically treated, the chemically treated sludge is then sonicated, and the sonicated sludge is returned to the biological treatment step. .
7). The method according to claim 1, wherein a part or all of the excess sludge is sonicated, the sonicated sludge is then heated, and the heated sludge is returned to the biological treatment step.
8). The method according to claim 1, wherein a part or all of the excess sludge is heated, the heated sludge is then sonicated, and the sonicated sludge is returned to the biological treatment step.
9. The surplus sludge is partly or wholly sonicated, the sonicated sludge is then warmed, the warmed sludge is then acid-fermented, and the acid-fermented sludge is subjected to a biological treatment process. The method according to the above item 1 for returning.
10. A part or all of the excess sludge is heated, the heated sludge is then subjected to ultrasonic treatment, the ultrasonically treated sludge is then subjected to acid fermentation treatment, and the acid-fermented sludge is subjected to a biological treatment process. The method according to the above item 1 for returning.
11. A part or all of the excess sludge is sonicated, the sonicated sludge is then chemically treated, the chemically treated sludge is then acid fermented, and the acid-fermented sludge is returned to the biological treatment process. 3. The method according to item 1 or 2 above.
12 A part or all of the excess sludge is chemically treated, the chemically treated sludge is then sonicated, the sonicated sludge is then acid fermented, and the acid-fermented sludge is returned to the biological treatment process. 3. The method according to item 1 or 2 above.
13. The method according to claim 1, wherein a part or all of the excess sludge is subjected to ultrasonic treatment while acid fermentation in an acid fermentation tank equipped with an ultrasonic transmitter, and the treated sludge is returned to the biological treatment step. .
14 The method according to claim 1, wherein a part or the whole of the excess sludge is ultrasonically treated while being heated in a heating tank equipped with an ultrasonic transmitter, and the treated sludge is returned to the biological treatment step. .
15. The first, second, third, and fourth items for controlling the sludge hydrodynamic residence time in the acid fermentation treatment so that the oxidation-reduction potential of the sludge in the acid fermentation treatment is -100 mV or less. , 9, 10, 11, 12, or 13.
16. The first, second, third, fourth, and the like, wherein a part of the organic waste water is directly supplied to the acid fermentation treatment so that the oxidation-reduction potential of the sludge in the acid fermentation treatment is -100 mV or less. The method according to any one of items 9, 10, 11, 12, or 13.
17. The first, second, third, and ninth items in which a part of the sludge subjected to the acid fermentation treatment is returned to the ultrasonic treatment so that the redox potential of the sludge in the acid fermentation treatment is −100 mV or less. The method according to any one of items 10 to 12, and
18. Any one of the above items 1, 2, or 4, wherein a part of the sludge subjected to ultrasonic treatment is returned to the acid fermentation treatment so that the oxidation-reduction potential of the sludge in the acid fermentation treatment is −100 mV or less. The method described in 1.
19. The method according to any one of Items 1 to 18, wherein a part or all of the excess sludge is concentrated to 1 to 10% by weight in terms of a sludge concentration, and the concentrated sludge is solubilized.
20. Organic wastewater is biologically treated in a biological treatment tank, the activated sludge mixed liquid discharged from the biological treatment tank is solid-liquid separated to generate precipitated sludge and treated water, and the precipitated sludge is used as excess sludge. Alternatively, the treatment method of organic wastewater is characterized in that the treatment sludge is returned to the biological treatment tank through the solubilization treatment specified in any one of the above-mentioned items 1 to 19 for the entire amount.
21. Organic wastewater is biologically treated in a biological treatment tank, the activated sludge mixed liquid discharged from the biological treatment tank is solid-liquid separated to generate precipitated sludge and treated water, and the precipitated sludge is used as excess sludge. Alternatively, the total amount is concentrated to 1 to 10% by weight as a sludge concentration, and the concentrated sludge is subjected to the solubilization treatment defined in any one of the above items 1 to 19 to return the treated sludge to the biological treatment tank. To treat organic wastewater.
22. An apparatus for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, and a device for solubilizing a part or all of the surplus sludge; And a pipe for returning the sludge treated in the solubilization treatment apparatus to the biological treatment process, and the solubilization treatment apparatus comprises an ultrasonic treatment apparatus, an acid fermentation treatment apparatus, a chemical treatment apparatus, and a heating treatment. A device comprising a combination with at least one of the devices.
23. The apparatus according to the above item 22, wherein the sludge solubilization apparatus is a chemical treatment apparatus using any one of ozone, hydrogen peroxide, an oxidizing agent, and an alkaline agent.
24. The apparatus according to Item 22, wherein the sludge solubilization apparatus includes an ultrasonic treatment apparatus for ultrasonically treating the sludge and an acid fermentation apparatus for subjecting the ultrasonic treatment sludge to an acid fermentation treatment.
25. The apparatus according to Item 22, wherein the sludge solubilization apparatus includes an acid fermentation apparatus that performs acid fermentation treatment on sludge and an ultrasonic treatment apparatus that performs ultrasonic treatment on the acid fermentation treatment sludge.
26. 24. The apparatus according to the above item 22 or 23, wherein the sludge solubilization apparatus comprises an ultrasonic treatment apparatus for ultrasonically treating sludge and a chemical treatment apparatus for chemically treating ultrasonic treatment sludge.
27. 24. The apparatus according to the above item 22 or 23, wherein the sludge solubilization treatment apparatus comprises a chemical treatment apparatus for chemically treating sludge and an ultrasonic treatment apparatus for ultrasonically treating the chemically treated sludge.
28. Item 22. The apparatus according to Item 22, wherein the sludge solubilization treatment device is constituted by an ultrasonic treatment device that ultrasonically treats sludge and a heating treatment device that heats the ultrasonic treatment sludge.
26. Item 22. The apparatus according to Item 22, wherein the sludge solubilization treatment device is constituted by a heating treatment device that heats sludge and an ultrasonic treatment device that ultrasonically treats the heat treatment sludge.
30. The sludge solubilization treatment apparatus is composed of an ultrasonic treatment apparatus for ultrasonically treating sludge, a heating treatment apparatus for heating ultrasonic treatment sludge, and an acid fermentation apparatus for subjecting the heated sludge to acid fermentation treatment. 23. The apparatus according to item 22 above.
31. The sludge solubilization treatment device comprises a heating treatment device that heats sludge, an ultrasonic treatment device that ultrasonically treats the heated sludge, and an acid fermentation device that performs acid fermentation treatment on the ultrasonic treatment sludge. 23. The apparatus according to item 22 above.
32. The sludge solubilization treatment apparatus is composed of an ultrasonic treatment apparatus for ultrasonically treating sludge, a chemical treatment apparatus for chemically treating ultrasonic treatment sludge, and an acid fermentation apparatus for subjecting chemical treatment sludge to acid fermentation treatment. 24. An apparatus according to item 22 or 23.
33. The sludge solubilization treatment apparatus comprises a chemical treatment apparatus for chemically treating sludge, an ultrasonic treatment apparatus for ultrasonically treating chemical treatment sludge, and an acid fermentation apparatus for subjecting ultrasonic treatment sludge to acid fermentation treatment. 24. An apparatus according to item 22 or 23.
34. The apparatus according to Item 22, wherein the sludge solubilization apparatus is constituted by an acid fermentation tank equipped with an ultrasonic transmitter.
35. The apparatus according to Item 22, wherein the sludge solubilization apparatus is constituted by a heating tank equipped with an ultrasonic transmitter.
36. The above-mentioned items 22 to 35, further comprising a concentrating device that receives a part or all of the excess sludge and condensing the sludge, and a pipe that supplies the solubilizing device with the concentrated sludge discharged from the concentrating device. The apparatus in any one of.
37. A biological treatment tank for receiving organic wastewater to perform biological treatment; a solid-liquid separation apparatus for producing a precipitated sludge and treated water by solid-liquid separation of an activated sludge mixed liquid discharged from the biological treatment tank; From the sludge solubilization apparatus, the sludge solubilization apparatus specified in any one of Items to 36, a pipe for supplying a part or all of the precipitated sludge discharged from the solid-liquid separator to the sludge solubilization apparatus An organic wastewater treatment apparatus comprising a pipe for returning discharged sludge to a biological treatment tank.
38. A biological treatment tank that receives organic wastewater and performs biological treatment, a solid-liquid separation device that produces a precipitated sludge and treated water by solid-liquid separation of the activated sludge mixed liquid discharged from the biological treatment tank, and the solid-liquid separation A concentrating device that receives a part or all of the precipitated sludge discharged from the separation device and concentrates the sludge, a sludge solubilization treatment device defined in any one of Items 22 to 36, and a concentrating device. An organic wastewater treatment apparatus comprising: a pipe for supplying concentrated sludge to the solubilization treatment apparatus; and a pipe for returning the treatment sludge discharged from the solubilization treatment apparatus to a biological treatment tank.
The following examples further illustrate the present invention. The following examples show some specific examples for embodying the present invention, and the present invention is not limited to these descriptions.

図9は、本実施例で用いた、有機性廃水の生物処理プロセスからの余剰汚泥を、汚泥可溶化手段として超音波処理と酸発酵処理との組み合わせにより液化する実験装置である。本実施例では、超音波処理槽11において用いる超音波発振機として、消費力700W、発振周波数20kHzのものを用いた。超音波ホーンの断面積は19.6cmであり、断面積あたりの消費電力は36W/cmであった。
原水1として下水を用いた。生物処理槽8として、脱窒槽8aと硝化槽8bとを有する循環式の硝化脱窒槽を用いて原水1の生物処理を行った。原水1を流量10m/dで生物処理槽8の脱窒槽8aに供給し、続いて硝化槽8bで処理を行なった。生物処理槽8内での活性汚泥濃度は約3000mg−SS/Lであった。生物処理槽8の硝化槽8bから排出される活性汚泥混合液を固液分離槽9に供給した。本実施例では、固液分離槽9として沈殿池方式を用い、ここで活性汚泥混合液を処理水2と沈殿汚泥3に分離した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。
沈殿汚泥3のうちの1.9m/dを汚泥濃縮機10に供給して汚泥濃度5重量%まで濃縮した。濃縮汚泥4は超音波反応槽11に供給して超音波処理を行った。汚泥あたりの超音波強度は159kJ/L、流路あたりの強度は36W/cmであった。超音波処理により、S−CODCrはCODCrの10%の4700mg/Lとなった。超音波処理後の汚泥は、酸発酵槽12に供給し、1日滞留させたのち生物処理槽8の脱窒槽8aに返送した。
酸発酵槽では、系のpHが5.5となるようにpHを調整した。酸発酵処理により、S−CODCrは9000mg/Lとなり、うち有機酸が4500mg/Lを占めた。
表1に、実施例1での超音波処理前の濃縮汚泥4と、超音波処理後の汚泥5、酸発酵処理後の汚泥6の性状を示す。表1より、実施例1では、超音波処理汚泥5、酸発酵汚泥6は、それぞれ処理前の段階よりも溶解性成分が増加しており、汚泥が液化したことが分かる。また、酸発酵汚泥6には有機酸の生成が認められた。なお、以下の表では、SSなどを「−」として数値を示していないところがある。これは、汚泥の液化が進んだことが、溶解性のCODCrやKj−Nが増加したことにより判断できたため、汚泥の液化の判断に必要のないSSや全CODCrやKj−Nを測定しなかったことによるものである。

Figure 2004005199
表2に、実施例1の本発明にかかる余剰汚泥処理を組合わせた場合の有機性廃水の生物処理システムの処理水2の水質を示す。表2から分かるように、実施例1では、SSが5mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができた。
Figure 2004005199
図10に、実施例1による余剰汚泥処理を組合わせた生物処理プロセスにおける生物処理槽8(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。約60日間の連続運転の間で生物処理槽8内の汚泥量は約10kgで安定しており、余剰汚泥の発生量を抑えることができたことが分かる。
比較例1
比較例1として、図11に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を超音波により液化して生物処理に戻す処理を行なった。比較例1で用いた超音波発振機は実施例1と同じ装置を用いた。原水1として下水を用い、流量10m/dで生物処理槽8の脱窒槽8aに供給し、続いて硝化槽8bで処理した。生物処理槽8内の活性汚泥濃度は約3000mg−SS/Lであった。生物処理槽8の硝化槽8bから排出される活性汚泥混合液を固液分離槽9に供給した。
比較例1では固液分離槽9に沈殿池方式を用い、ここで活性汚泥混合液を処理水2と沈殿汚泥3とに分離した。沈殿汚泥3は流量4m/dで、汚泥濃度は約13000mg−SS/Lであった。
比較例1では、沈殿汚泥3の全量を超音波処理槽11に供給して超音波処理を行なった。実施例1の超音波装置(消費電力700W)を用い、汚泥あたりの超音波濃度は15.2kJ/Lとなった。この強度でのCODCrの液化率は1%であった。超音波処理後の汚泥5は生物処理槽8の脱窒槽8aに返送した。
表3に比較例1での超音波処理前の沈殿汚泥3と超音波処理後の汚泥5の性状を示す。表3より、比較例1では、超音波処理により汚泥が液化したことが示されたが、酸発酵槽がないため実施例1と比較して、溶解性成分が少なくなったことが分かる。
Figure 2004005199
表4に、比較例1の余剰汚泥処理を組合わせた場合の生物処理システムの処理水2の水質を示す。表4より、比較例1では実施例1よりもSS、CODCrとも高くなり、水質が悪化したことが分かる。また、処理水のSSが実施例1よりも高く、図12から生物処理槽8内の汚泥量が減少したことから、生物処理槽8内の汚泥も流出したと考えられる。
Figure 2004005199
図12に、比較例1による余剰汚泥処理を組合わせた生物処理プロセスにおける生物処理槽8(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。比較例1では汚泥の流出が激しく35日間で運転を打ち切った。比較例1のシステムでは安定した生物処理ができなかった。FIG. 9 shows an experimental apparatus used in this example for liquefying excess sludge from the biological treatment process of organic wastewater by a combination of ultrasonic treatment and acid fermentation treatment as sludge solubilization means. In this embodiment, the ultrasonic oscillator used in the ultrasonic treatment tank 11 is one having a power consumption of 700 W and an oscillation frequency of 20 kHz. The cross-sectional area of the ultrasonic horn was 19.6 cm 2 , and the power consumption per cross-sectional area was 36 W / cm 2 .
Sewage was used as raw water 1. As the biological treatment tank 8, a biological treatment of the raw water 1 was performed using a circulation type nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a of the biological treatment tank 8 at a flow rate of 10 m 3 / d, and subsequently treated in the nitrification tank 8b. The activated sludge concentration in the biological treatment tank 8 was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8 b of the biological treatment tank 8 was supplied to the solid-liquid separation tank 9. In this example, a sedimentation basin system was used as the solid-liquid separation tank 9, and the activated sludge mixed liquid was separated into the treated water 2 and the precipitated sludge 3 here. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L.
1.9 m 3 / d of the precipitated sludge 3 was supplied to the sludge concentrator 10 and concentrated to a sludge concentration of 5% by weight. The concentrated sludge 4 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment. The ultrasonic intensity per sludge was 159 kJ / L, and the intensity per flow path was 36 W / cm 2 . By sonication, S-COD Cr became 10% of COD Cr , 4700 mg / L. The sludge after ultrasonic treatment was supplied to the acid fermentation tank 12 and retained for 1 day, and then returned to the denitrification tank 8a of the biological treatment tank 8.
In the acid fermenter, the pH was adjusted so that the pH of the system was 5.5. By the acid fermentation treatment, S-COD Cr was 9000 mg / L, of which organic acid accounted for 4500 mg / L.
Table 1 shows the properties of the concentrated sludge 4 before ultrasonic treatment, the sludge 5 after ultrasonic treatment, and the sludge 6 after acid fermentation treatment in Example 1. From Table 1, it can be seen that in Example 1, the ultrasonically treated sludge 5 and the acid-fermented sludge 6 each have more soluble components than the pre-treatment stage, and the sludge has been liquefied. Moreover, the production | generation of the organic acid was recognized by the acid fermentation sludge 6. In the following table, there are places where SS and the like are not represented by “−”. This is because the liquefaction of sludge has progressed due to the increase in soluble COD Cr and Kj-N, so SS, total COD Cr and Kj-N, which are not necessary for the determination of sludge liquefaction, are measured. It is because it did not.
Figure 2004005199
Table 2 shows the quality of the treated water 2 of the organic wastewater biological treatment system when the surplus sludge treatment according to the present invention of Example 1 is combined. As can be seen from Table 2, in Example 1, it was possible to obtain good treated water quality with SS of 5 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
FIG. 10 shows the progress of the amount of sludge in the biological treatment tank 8 (denitrification tank 8a and nitrification tank 8b) in the biological treatment process in which surplus sludge treatment according to Example 1 is combined. It can be seen that the amount of sludge in the biological treatment tank 8 was stable at about 10 kg during the continuous operation for about 60 days, and the amount of excess sludge generated could be suppressed.
Comparative Example 1
As Comparative Example 1, the apparatus shown in FIG. 11 was used to perform a process of liquefying excess sludge generated from the biological treatment process of organic waste water with ultrasonic waves and returning it to the biological treatment. The ultrasonic oscillator used in Comparative Example 1 was the same as that used in Example 1. Sewage was used as the raw water 1 and supplied to the denitrification tank 8a of the biological treatment tank 8 at a flow rate of 10 m 3 / d, followed by treatment in the nitrification tank 8b. The activated sludge concentration in the biological treatment tank 8 was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8 b of the biological treatment tank 8 was supplied to the solid-liquid separation tank 9.
In Comparative Example 1, a sedimentation basin system was used for the solid-liquid separation tank 9, and the activated sludge mixed liquid was separated into the treated water 2 and the precipitated sludge 3. The precipitated sludge 3 had a flow rate of 4 m 3 / d and a sludge concentration of about 13000 mg-SS / L.
In Comparative Example 1, the entire amount of the precipitated sludge 3 was supplied to the ultrasonic treatment tank 11 and subjected to ultrasonic treatment. Using the ultrasonic device of Example 1 (power consumption 700 W), the ultrasonic concentration per sludge was 15.2 kJ / L. The liquefaction rate of COD Cr at this strength was 1%. The sludge 5 after ultrasonic treatment was returned to the denitrification tank 8 a of the biological treatment tank 8.
Table 3 shows the properties of the precipitated sludge 3 before ultrasonic treatment and the sludge 5 after ultrasonic treatment in Comparative Example 1. From Table 3, it was shown in Comparative Example 1 that the sludge was liquefied by ultrasonic treatment. However, since there is no acid fermentation tank, it can be seen that the soluble components are reduced as compared with Example 1.
Figure 2004005199
In Table 4, the quality of the treated water 2 of the biological treatment system at the time of combining the surplus sludge process of the comparative example 1 is shown. From Table 4, it can be seen that in Comparative Example 1, both SS and COD Cr were higher than in Example 1 and the water quality deteriorated. Moreover, since SS of treated water is higher than Example 1, and the sludge amount in the biological treatment tank 8 decreased from FIG. 12, it is thought that the sludge in the biological treatment tank 8 also flowed out.
Figure 2004005199
FIG. 12 shows the progress of the amount of sludge in the biological treatment tank 8 (denitrification tank 8a and nitrification tank 8b) in the biological treatment process in which surplus sludge treatment according to Comparative Example 1 is combined. In Comparative Example 1, the sludge flowed out so that the operation was terminated in 35 days. In the system of Comparative Example 1, stable biological treatment could not be performed.

実施例2として、図13に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を、汚泥可溶化手段として酸発酵処理と超音波処理とをこの順番で液化して生物処理槽に戻す処理を行なった。実施例2での酸発酵槽12の汚泥滞留時間は2日に設定した。超音波反応槽11に設置する超音波発振器としては、消費電力700W、発振周波数20kHzのものを用いた。超音波処理装置は、1日あたり3.1時間運転し、この時の超音波処理装置の消費電力は2.2kWhであった。
実施例2では、原水1として下水を用いた。生物処理槽としては、脱窒槽8aと硝化槽8bに分かれた循環式の硝化脱窒槽を用いて原水の生物処理を行った。原水1を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8bの活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液を沈殿池9に供給して、処理水2と沈殿汚泥3に分離した。また、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。沈殿汚泥の3.6m/dを返送汚泥として脱窒槽8aに返送した。沈殿汚泥の残りを汚泥濃縮槽10に供給し、重力濃縮により2重量%まで濃縮した。濃縮汚泥4は酸発酵槽12に供給して、実施例1と同様の条件で酸発酵処理を行った。酸発酵汚泥5は次に超音波反応槽11で超音波処理した後、脱窒槽8aに返送した。
表5に、実施例2における濃縮汚泥4、酸発酵汚泥6、超音波処理汚泥5の性状を示す。表5より、酸発酵処理と超音波処理を行うことで汚泥の溶解性成分が増加しており、汚泥が液化したことが分かる。

Figure 2004005199
表6に、実施例2の本発明にかかる余剰汚泥処理を組合わせた生物処理システムの処理水2の水質を示す。表6より、実施例2では、SSが10mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができたことが分かる。
Figure 2004005199
図14に、実施例2による余剰汚泥処理を組合わせた生物処理プロセスにおける生物処理槽(脱窒槽8aと硝化槽8b)内の合計汚泥量の経過を示す。余剰汚泥の排出を行なわずに連続運転を約60日間行ったが、汚泥量は約9kgで安定しており、余剰汚泥の発生量を抑制することができた。沈殿汚泥に対して酸発酵処理と超音波処理を行わない対照系で汚泥の発生量を求めたところ、1日あたり約0.7kgの余剰汚泥が発生しており、酸発酵処理と超音波処理により余剰汚泥の発生量を抑制することができたことが分かった。
比較例2
比較例2として、図11に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を超音波処理により液化して生物処理に戻す実験を行なった。比較例2で用いた超音波発振器は、実施例2と同じ装置を用いた。原水1としては下水を用いた。原水1を流量は10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8bの活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液を沈殿池9に供給して、処理水2と沈殿汚泥3に分離した。沈殿汚泥3の汚泥濃度は約10000mg−SS/Lであった。
本比較例では、沈殿汚泥3を全量、超音波反応槽11に供給して超音波処理した。超音波処理後の汚泥は、脱窒槽8aに返送した。超音波発振器の消費電力は22.2kW/hであった。
表7に、本比較例2での超音波処理前の沈殿汚泥3と超音波処理後の汚泥5の性状を示す。表7より、本比較例2では、超音波処理により汚泥が液化したことが示されたが、汚泥が濃縮されていないので液化量が少なくなったことが分かる。
Figure 2004005199
表8に、比較例2の余剰汚泥処理を組合わせた生物処理システムの処理水2の水質を示す。表8より、本比較例2では、実施例2よりもSS、CODCrとも高くなり水質が悪化したことが分かる。また、また、処理水のSSが実施例2よりも高く、図15から生物処理槽(脱窒槽8a及び硝化槽8b)内の汚泥量が減少したことから、脱窒槽8aや硝化槽8b内の汚泥が流出したと考えられる。
Figure 2004005199
図15に、比較例2による余剰汚泥処理を組合わせた生物処理プロセスにおける生物処理槽(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。比較例2では汚泥の流出が激しく35日間で運転を打ち切った。比較例2のシステムでは安定した生物処理ができなかった。As Example 2, using the apparatus shown in FIG. 13, surplus sludge generated from the biological treatment process of organic waste water is liquefied by acid fermentation treatment and ultrasonic treatment in this order as sludge solubilization means, and biological treatment is performed. The process which returns to a tank was performed. The sludge residence time in the acid fermentation tank 12 in Example 2 was set to 2 days. As an ultrasonic oscillator to be installed in the ultrasonic reaction tank 11, one having a power consumption of 700 W and an oscillation frequency of 20 kHz was used. The ultrasonic processing apparatus was operated for 3.1 hours per day, and the power consumption of the ultrasonic processing apparatus at this time was 2.2 kWh.
In Example 2, sewage was used as the raw water 1. As the biological treatment tank, biological treatment of raw water was performed using a circulation type nitrification denitrification tank divided into a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. 3.6 m 3 / d of the precipitated sludge was returned to the denitrification tank 8 a as return sludge. The remainder of the precipitated sludge was supplied to the sludge concentration tank 10 and concentrated to 2% by weight by gravity concentration. The concentrated sludge 4 was supplied to the acid fermentation tank 12 and subjected to acid fermentation treatment under the same conditions as in Example 1. The acid-fermented sludge 5 was then ultrasonically treated in the ultrasonic reaction tank 11 and then returned to the denitrification tank 8a.
Table 5 shows the properties of the concentrated sludge 4, acid-fermented sludge 6, and sonicated sludge 5 in Example 2. From Table 5, it turns out that the soluble component of sludge has increased by performing acid fermentation treatment and ultrasonic treatment, and sludge has liquefied.
Figure 2004005199
In Table 6, the quality of the treated water 2 of the biological treatment system which combined the excess sludge process concerning this invention of Example 2 is shown. From Table 6, it can be seen that in Example 2, it was possible to obtain good treated water quality with SS of 10 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
In FIG. 14, progress of the total amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the biological treatment process which combined the excess sludge process by Example 2 is shown. Although continuous operation was performed for about 60 days without discharging excess sludge, the amount of sludge was stable at about 9 kg, and the generation amount of excess sludge could be suppressed. When the amount of sludge generated in a control system that does not perform acid fermentation treatment and ultrasonic treatment on the precipitated sludge was found, about 0.7 kg of excess sludge was generated per day. Acid fermentation treatment and ultrasonic treatment It was found that the generation amount of excess sludge could be suppressed.
Comparative Example 2
As Comparative Example 2, an experiment shown in FIG. 11 was used to conduct an experiment in which excess sludge generated from the biological treatment process of organic waste water was liquefied by ultrasonic treatment and returned to the biological treatment. The same apparatus as in Example 2 was used as the ultrasonic oscillator used in Comparative Example 2. As raw water 1, sewage was used. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. The sludge concentration of the precipitated sludge 3 was about 10,000 mg-SS / L.
In this comparative example, the entire amount of the precipitated sludge 3 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment. The sludge after ultrasonic treatment was returned to the denitrification tank 8a. The power consumption of the ultrasonic oscillator was 22.2 kW / h.
Table 7 shows the properties of the precipitated sludge 3 before ultrasonic treatment and the sludge 5 after ultrasonic treatment in Comparative Example 2. Table 7 shows that in this comparative example 2, the sludge was liquefied by the ultrasonic treatment, but the liquefaction amount was reduced because the sludge was not concentrated.
Figure 2004005199
In Table 8, the quality of the treated water 2 of the biological treatment system which combined the excess sludge process of the comparative example 2 is shown. From Table 8, it can be seen that in Comparative Example 2, both SS and COD Cr were higher than in Example 2 and the water quality deteriorated. Moreover, SS of treated water is higher than Example 2, and since the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) decreased from FIG. 15, the denitrification tank 8a and nitrification tank 8b It is thought that sludge has flowed out.
Figure 2004005199
FIG. 15 shows the progress of the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the biological treatment process in which surplus sludge treatment according to Comparative Example 2 is combined. In Comparative Example 2, the sludge flowed out so that the operation was terminated in 35 days. In the system of Comparative Example 2, stable biological treatment could not be performed.

実施例3として、図16に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を、汚泥可溶化手段として超音波処理とオゾン処理との組み合わせにより液化する実験を行なった。本実施例3で用いる超音波発振機としては、消費電力700W、発振周波数20kHzのものを用いた。超音波ホーンの断面積は19.6cmであり、断面積あたりの消費電力は36W/cmであった。
本実施例3では原水1として下水を用いた。生物処理槽として、脱窒槽8aと硝化槽8bとを有する循環式の硝化脱窒槽により原水の生物処理を行った。原水を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8b内の活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液は、沈殿池9に供給して、ここで処理水2と沈殿汚泥3に分離した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。なお、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。
沈殿汚泥3のうちの1.9m/dを汚泥濃縮機10に供給して汚泥濃度5%まで濃縮した沈殿汚泥3の残りは脱窒槽8aに返送した。汚泥濃縮機10で得られた濃縮汚泥4を、超音波反応槽11に供給して超音波処理を行った。超音波処理後の汚泥5を、オゾン反応槽45に供給した。オゾン反応槽45から排出されるオゾン処理汚泥46は、脱窒槽8aに返送した。表9に、実施例3での濃縮汚泥4、超音波処理後の汚泥5、オゾン処理後の汚泥46の性状を示す。表9より、本実施例3では、超音波処理汚泥、オゾン処理汚泥は、それぞれ処理前の段階より溶解性成分が増加しており、汚泥が液化したことがわかる。

Figure 2004005199
表10に、実施例3の本発明にかかる余剰汚泥処理を組合わせた場合の生物処理システムの処理水2の水質を示す。表10より、実施例3ではSSが9mg/L、CODCrも27mg/Lの良好な処理水水質を得ることができたことがわかる。なお、汚泥の減容化処理を行わない単純な活性汚泥処理での処理水のCODCrは、10〜30mg/Lの範囲で推移するので、本実施例での処理水水質は、通常処理と同等の処理水水質であるといえる。汚泥の減容化処理を行った場合には、処理水水質が通常処理の場合より悪化する傾向にあるが、本実施例ではそのような傾向はみられなかった。
Figure 2004005199
図17に、実施例3の余剰汚泥処理を組合わせた生物処理プロセスにおける連続処理試験での生物処理槽(脱窒槽8aと硝化槽8b)内の汚泥量の経過を示す。脱窒槽8aと硝化槽8bの合計汚泥量は約9kgで安定していた。また、汚泥処理を行わない対照系での汚泥発生量は1日あたり約700gであり、余剰汚泥の発生量を抑制することができたことが分かる。実施例3での汚泥処理の消費電力はオゾン単独処理の約1/2であり、エネルギーを大幅に節約できた。As Example 3, using the apparatus shown in FIG. 16, an experiment was conducted in which excess sludge generated from the biological treatment process of organic wastewater was liquefied by a combination of ultrasonic treatment and ozone treatment as sludge solubilization means. As the ultrasonic oscillator used in the third embodiment, one having a power consumption of 700 W and an oscillation frequency of 20 kHz was used. The cross-sectional area of the ultrasonic horn was 19.6 cm 2 , and the power consumption per cross-sectional area was 36 W / cm 2 .
In Example 3, sewage was used as the raw water 1. As a biological treatment tank, the raw water was biologically treated by a circulating nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. Raw water was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9, where it was separated into treated water 2 and precipitated sludge 3. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a.
1.9 m 3 / d of the precipitated sludge 3 was supplied to the sludge concentrator 10 and the remainder of the precipitated sludge 3 concentrated to a sludge concentration of 5% was returned to the denitrification tank 8a. The concentrated sludge 4 obtained by the sludge concentrator 10 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment. The sludge 5 after the ultrasonic treatment was supplied to the ozone reaction tank 45. The ozone-treated sludge 46 discharged from the ozone reaction tank 45 was returned to the denitrification tank 8a. Table 9 shows the properties of the concentrated sludge 4, the sludge 5 after ultrasonic treatment, and the sludge 46 after ozone treatment in Example 3. From Table 9, it can be seen that in Example 3, the ultrasonically treated sludge and the ozone treated sludge each have increased soluble components from the stage before the treatment, and the sludge has been liquefied.
Figure 2004005199
Table 10 shows the quality of the treated water 2 of the biological treatment system when the surplus sludge treatment according to the present invention in Example 3 is combined. From Table 10, it can be seen that in Example 3, it was possible to obtain a good treated water quality with SS of 9 mg / L and COD Cr of 27 mg / L. In addition, since COD Cr of the treated water in the simple activated sludge treatment which does not perform sludge volume reduction treatment changes in the range of 10 to 30 mg / L, the quality of the treated water in this example is the same as that of the normal treatment. It can be said that the treated water quality is equivalent. When sludge volume reduction treatment is performed, the quality of the treated water tends to be worse than in the case of normal treatment, but such a tendency was not observed in this example.
Figure 2004005199
FIG. 17 shows the progress of the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the continuous treatment test in the biological treatment process in which the surplus sludge treatment of Example 3 is combined. The total amount of sludge in the denitrification tank 8a and the nitrification tank 8b was stable at about 9 kg. In addition, the amount of sludge generated in the control system without sludge treatment was about 700 g per day, indicating that the amount of excess sludge generated could be suppressed. The power consumption of the sludge treatment in Example 3 was about ½ of the ozone alone treatment, and energy was saved significantly.

実施例4として、図18に示す装置を用いて有機性廃水の生物処理プロセスより発生した余剰汚泥を、超音波処理とアルカリ処理との組み合わせにより液化する実験を行なった。
実施例4では原水1として下水を用いた。生物処理槽としては、脱窒槽8aと硝化槽8bとを有する循環式の硝化脱窒槽により原水の生物処理を行った。原水1を、流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8b内の活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液を沈殿池9に供給して、処理水2と沈殿汚泥3に分離した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。なお、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。
沈殿汚泥3のうちの1.9m/dを汚泥濃縮機10に供給して汚泥濃度5%まで濃縮した。汚泥濃縮機10で得られた濃縮汚泥4は、超音波反応槽11に供給して実施例3と同様の条件で超音波処理を行った。超音波処理後の汚泥5は、アルカリ反応槽47に供給した。実施例4では、アルカリ反応槽47において、アルカリとして水酸化ナトリウム溶液を汚泥に添加した。アルカリ処理後の汚泥48は脱窒槽8aに返送した。表11に、実施例4での濃縮汚泥4、超音波処理後の汚泥5、アルカリ処理後の汚泥48の性状を示す。表11より、実施例4では、超音波処理汚泥、アルカリ処理汚泥は、それぞれ処理前の段階より溶解性成分が増加しており、汚泥が液化したことがわかる。

Figure 2004005199
表12に、実施例4の本発明にかかる余剰汚泥処理を組合わせた場合の生物処理システムの処理水2の水質を示す。表12より、実施例4では、SSが11mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができたことがわかる。
Figure 2004005199
図19に、実施例4の余剰汚泥処理を組合わせた場合の生物処理システムの連続処理試験における生物処理槽(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。脱窒槽8aと硝化槽8b内の合計汚泥量は約9kgで安定していた。また、汚泥処理を行わない対照系での汚泥発生量は1日あたり約700gであり、余剰汚泥の発生量を抑制することができたことが分かる。実施例4での汚泥処理における水酸化ナトリウムの消費量は、アルカリ単独処理の約80%に減らすことができた。As Example 4, an experiment was performed in which excess sludge generated from the biological treatment process of organic wastewater was liquefied by a combination of ultrasonic treatment and alkali treatment using the apparatus shown in FIG.
In Example 4, sewage was used as the raw water 1. As the biological treatment tank, the raw water was biologically treated by a circulating nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a.
1.9 m 3 / d of the precipitated sludge 3 was supplied to the sludge concentrator 10 and concentrated to a sludge concentration of 5%. The concentrated sludge 4 obtained by the sludge concentrator 10 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment under the same conditions as in Example 3. The sludge 5 after the ultrasonic treatment was supplied to the alkali reaction tank 47. In Example 4, in the alkaline reaction tank 47, a sodium hydroxide solution was added to the sludge as an alkali. The sludge 48 after the alkali treatment was returned to the denitrification tank 8a. Table 11 shows the properties of the concentrated sludge 4 in Example 4, the sludge 5 after ultrasonic treatment, and the sludge 48 after alkali treatment. From Table 11, it can be seen that in Example 4, the ultrasonically treated sludge and the alkali-treated sludge have increased soluble components from the stage before the treatment, and the sludge has been liquefied.
Figure 2004005199
Table 12 shows the quality of the treated water 2 of the biological treatment system when the surplus sludge treatment according to the present invention in Example 4 is combined. From Table 12, it can be seen that in Example 4, it was possible to obtain good treated water quality with SS of 11 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
FIG. 19 shows the progress of the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the continuous treatment test of the biological treatment system when the surplus sludge treatment of Example 4 is combined. The total amount of sludge in the denitrification tank 8a and the nitrification tank 8b was stable at about 9 kg. In addition, the amount of sludge generated in the control system without sludge treatment was about 700 g per day, indicating that the amount of excess sludge generated could be suppressed. The consumption of sodium hydroxide in the sludge treatment in Example 4 could be reduced to about 80% of the alkali alone treatment.

実施例5として、図20に示す装置を用いて有機性廃水の生物処理プロセスより発生した余剰汚泥を、超音波処理と加温処理の組み合わせにより液化する実験を行なった。
実施例5では原水1として下水を用いた。生物処理槽としては、脱窒槽8aと硝化槽8bを有する循環式の硝化脱窒槽により原水の生物処理を行った。原水を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8a及び硝化槽8b内の活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液は、沈殿池9に供給して処理水2と沈殿汚泥3に分離した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。なお、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。
沈殿汚泥3のうちの1.9m/dを汚泥濃縮機10に供給して汚泥濃度5%まで濃縮した。濃縮汚泥4は、超音波反応槽11に供給して実施例3と同様の条件で超音波処理を行った。超音波処理後の汚泥5は、加温槽17に供給して、約70℃で30分間、汚泥を加温した。加温処理された汚泥は脱窒槽13に返送した。表13に、実施例5での濃縮汚泥4、超音波処理後の汚泥5、加温処理後の汚泥18の性状を示す。表13より、本実施例5では、超音波処理汚泥5、加温処理汚泥18は、それぞれ処理前の段階より溶解性成分が増加しており、汚泥が液化したことがわかる。

Figure 2004005199
表14に、実施例5の余剰汚泥処理を組合わせた場合の生物処理システムにおける処理水2の水質を示す。表14より、実施例5では、SSが8mg/L、CODCrも25mg/Lの良好な処理水水質を得ることができたことがわかる。
Figure 2004005199
図21に、実施例5の余剰汚泥処理を組合わせた場合の生物処理システムの連続処理試験における生物処理槽(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。脱窒槽8aと硝化槽8b内の合計汚泥量は約9kgで安定していた。また、汚泥処理を行わない対照系での汚泥発生量は1日あたり約700gであり、余剰汚泥の発生量を抑制することができたことが分かる。
比較例3
比較例3として、図22に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を超音波処理のみにより液化する実験を行なった。本比較例3で用いた超音波発振機は、実施例3〜5と同じ装置を用いた。原水1として下水を用い、流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8a及び硝化槽8b内の活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液は、沈殿池9に供給し、処理水2と沈殿汚泥3に分離した。沈殿汚泥3の汚泥濃度は約13000mg−SS/Lであった。なお、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。
本比較例3においては、沈殿汚泥3を全量、超音波反応槽11に供給して、超音波処理を行なった。超音波処理後の汚泥5は脱窒槽8aに返送した。
表15に、本比較例3での沈殿汚泥3と超音波処理後の汚泥5の性状を示す。表15より、本比較例3では、超音波処理により汚泥が液化したことが示されているが、実施例3〜5と比較して溶解性成分の増加が少なかったことがわかる。
Figure 2004005199
表16に、比較例3の余剰汚泥処理を組合わせた場合の生物処理システムにおける処理水2の水質を示す。表16より、比較例4では実施例3〜5よりもSS、CODCrとも高くなり、水質が悪化したことがわかる。図23から生物処理槽内の汚泥量が減少したことから、生物処理槽内の汚泥も流出したと考えられる。
Figure 2004005199
図23に、比較例3の余剰汚泥処理を組合わせた場合の生物処理システムにおける生物処理槽(脱窒槽8a及び硝化槽8b)内の汚泥量の経過を示す。比較例3では汚泥の流出が激しく35日間で運転をうち切った。比較例4のシステムでは安定した生物処理ができなかった。As Example 5, an experiment was performed to liquefy excess sludge generated from a biological treatment process of organic wastewater by a combination of ultrasonic treatment and heating treatment using the apparatus shown in FIG.
In Example 5, sewage was used as the raw water 1. As a biological treatment tank, biological treatment of raw water was performed by a circulation type nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. Raw water was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into treated water 2 and precipitated sludge 3. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a.
1.9 m 3 / d of the precipitated sludge 3 was supplied to the sludge concentrator 10 and concentrated to a sludge concentration of 5%. The concentrated sludge 4 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment under the same conditions as in Example 3. The sludge 5 after the ultrasonic treatment was supplied to the heating tank 17, and the sludge was heated at about 70 ° C. for 30 minutes. The heated sludge was returned to the denitrification tank 13. Table 13 shows the properties of the concentrated sludge 4 in Example 5, the sludge 5 after ultrasonic treatment, and the sludge 18 after heating treatment. From Table 13, it can be seen that in Example 5, the ultrasonically treated sludge 5 and the heated treated sludge 18 have increased soluble components from the stage before the treatment, and the sludge has been liquefied.
Figure 2004005199
In Table 14, the water quality of the treated water 2 in the biological treatment system at the time of combining the excess sludge process of Example 5 is shown. From Table 14, it can be seen that in Example 5, it was possible to obtain good treated water quality with SS of 8 mg / L and COD Cr of 25 mg / L.
Figure 2004005199
FIG. 21 shows the progress of the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the continuous treatment test of the biological treatment system when the surplus sludge treatment of Example 5 is combined. The total amount of sludge in the denitrification tank 8a and the nitrification tank 8b was stable at about 9 kg. In addition, the amount of sludge generated in the control system without sludge treatment was about 700 g per day, indicating that the amount of excess sludge generated could be suppressed.
Comparative Example 3
As Comparative Example 3, using the apparatus shown in FIG. 22, an experiment was conducted in which excess sludge generated from the biological treatment process of organic wastewater was liquefied only by ultrasonic treatment. As the ultrasonic oscillator used in Comparative Example 3, the same apparatus as in Examples 3 to 5 was used. Sewage was used as the raw water 1 and supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. The sludge concentration of the precipitated sludge 3 was about 13000 mg-SS / L. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a.
In Comparative Example 3, the entire amount of the precipitated sludge 3 was supplied to the ultrasonic reaction tank 11 and subjected to ultrasonic treatment. The sludge 5 after the ultrasonic treatment was returned to the denitrification tank 8a.
Table 15 shows the properties of the precipitated sludge 3 and the sludge 5 after ultrasonic treatment in Comparative Example 3. From Table 15, it is shown that the sludge was liquefied by ultrasonic treatment in Comparative Example 3, but it was found that the increase in the solubility component was small compared to Examples 3-5.
Figure 2004005199
In Table 16, the water quality of the treated water 2 in the biological treatment system at the time of combining the surplus sludge process of the comparative example 3 is shown. From Table 16, it can be seen that in Comparative Example 4, both SS and COD Cr were higher than in Examples 3 to 5, and the water quality deteriorated. Since the amount of sludge in the biological treatment tank decreased from FIG. 23, it is considered that the sludge in the biological treatment tank also flowed out.
Figure 2004005199
FIG. 23 shows the progress of the amount of sludge in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the biological treatment system when the surplus sludge treatment of Comparative Example 3 is combined. In Comparative Example 3, the sludge flowed out and the operation was stopped in 35 days. In the system of Comparative Example 4, stable biological treatment could not be performed.

実施例6として、図24に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を、加温処理と超音波処理との組み合わせによって可溶化処理して生物処理に返送する処理を行なった。本実施例6での加温処理槽17の温度は70℃、滞留時間は30分に設定した。超音波反応槽11に取り付ける超音波発振機としては、消費電力700W、発振周波数20kHzのもの用いた。超音波処理装置は、1日あたり48分運転し、この時の超音波処理の消費電力は0.56kWhであった。
本実施例6では、原水1として下水を用いた。生物処理槽としては、脱窒槽8aと硝化槽8bとに分かれた循環式の硝化脱窒槽を用いて原水1の生物処理を行った。原水1を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8bの活性汚泥濃度は約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液を沈殿池9に供給して処理水2と沈殿汚泥3に分離した。また、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。この沈殿汚泥3のうちの0.58m/dを汚泥濃縮機10に供給し、汚泥濃度5重量%まで汚泥を濃縮した。沈殿汚泥の残りは脱窒槽8aに返送した。濃縮汚泥4を加温処理槽8に供給し、70℃に加温した後、超音波反応槽11にて超音波処理を行った。超音波処理を行なった汚泥5は脱窒槽8aに返送した。
表17に、本実施例6における濃縮汚泥4、加温処理汚泥18、超音波処理汚泥5の性状を示す。表17より、加温処理と超音波処理とを行うことで溶解性成分が増加しており、汚泥が液化したことが分かる。

Figure 2004005199
表18に、実施例6の余剰汚泥処理を組合わせた生物処理プロセスにおける処理水2の水質を示す。表18より、実施例6では、SSが10mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができたことが分かる。
Figure 2004005199
図25に実施例6による余剰汚泥処理を組合わせた生物処理プロセスにおける生物処理槽(脱窒槽8aと硝化槽8b)内の合計汚泥量の経過を示す。本実施例6では、余剰汚泥の排出をせずに連続運転を約60日間行ったが、汚泥量は約9kgで安定しており、余剰汚泥の発生量を抑制することができた。分離汚泥に対して加温処理と超音波処理を行わない対照系で汚泥発生量を求めたところ、1日あたり約0.7kgの余剰汚泥が発生しており、加温と超音波処理により余剰汚泥の発生量を抑制することができたことが分かる。As Example 6, the apparatus shown in FIG. 24 is used to solubilize surplus sludge generated from the biological treatment process of organic wastewater by a combination of warming treatment and ultrasonic treatment and return it to the biological treatment. Was done. The temperature of the heating treatment tank 17 in Example 6 was set to 70 ° C., and the residence time was set to 30 minutes. As an ultrasonic oscillator to be attached to the ultrasonic reaction tank 11, one having a power consumption of 700 W and an oscillation frequency of 20 kHz was used. The ultrasonic treatment apparatus was operated for 48 minutes per day, and the power consumption of the ultrasonic treatment at this time was 0.56 kWh.
In Example 6, sewage was used as the raw water 1. As the biological treatment tank, biological treatment of the raw water 1 was performed using a circulation type nitrification denitrification tank divided into a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. 0.58 m 3 / d of the precipitated sludge 3 was supplied to the sludge concentrator 10 to concentrate the sludge to a sludge concentration of 5% by weight. The remainder of the precipitated sludge was returned to the denitrification tank 8a. The concentrated sludge 4 was supplied to the heating treatment tank 8, heated to 70 ° C., and then subjected to ultrasonic treatment in the ultrasonic reaction tank 11. The sludge 5 subjected to ultrasonic treatment was returned to the denitrification tank 8a.
Table 17 shows the properties of the concentrated sludge 4, the warmed sludge 18, and the ultrasonically treated sludge 5 in Example 6. From Table 17, it turns out that the soluble component has increased by performing a heating process and an ultrasonic treatment, and the sludge was liquefied.
Figure 2004005199
In Table 18, the water quality of the treated water 2 in the biological treatment process which combined the excess sludge process of Example 6 is shown. From Table 18, it can be seen that in Example 6, it was possible to obtain good treated water quality with SS of 10 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
FIG. 25 shows the progress of the total sludge amount in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in the biological treatment process in which surplus sludge treatment according to Example 6 is combined. In Example 6, continuous operation was performed for about 60 days without discharging excess sludge, but the amount of sludge was stable at about 9 kg, and the generation amount of excess sludge could be suppressed. When the amount of sludge generated was determined in a control system that did not perform heating and sonication on the separated sludge, approximately 0.7 kg of excess sludge was generated per day, and surplus was generated by heating and sonication. It can be seen that the amount of sludge generated can be suppressed.

本実施例では、余剰汚泥を超音波処理した後、汚泥貯留槽で嫌気条件下で貯留して酸発酵を行なわせて汚泥を更に可溶化する揚合の、汚泥貯留槽内の酸化還元電位(ORP)と汚泥の液化度合との関係について実験を行った。この実験では、下水処理で発生した余剰汚泥(汚泥濃度1.1%)を、超音波処理槽で200Wの超音波発振器で液化処理を行い、その後、汚泥貯留槽(酸発酵槽)内で嫌気状態で汚泥を貯留し、ORPを測定しながら撹拌した。超音波処理前の余剰汚泥と、超音波処理後の汚泥、並びに貯留槽内で一定時間撹拌した後の汚泥の性状を表19に示す。

Figure 2004005199
表19より、貯留槽内でのORPが低下するにしたがって溶解性窒素が増加しており、汚泥の液化が進んだことが分かる。ORPが−186mVとなった撹拌18時間で溶解性ケルダール窒素が97mg/Lに達しており、未処理汚泥に対する液化率が14%になった。この結果より、ORPが、貯留槽(酸発酵槽)での最適の撹拌時間(貯留時間)を決定する目安になると考えらる。なお、本発明において「未処理汚泥に対する液化率」とは、汚泥中の固形分に対して、液化処理によって溶解性成分(孔径1μmの濾紙を通過できる成分)に変化した割合を意味し、下式で算出されるものである。
Figure 2004005199
In this embodiment, after surplus sludge is sonicated, it is stored in anaerobic conditions in the sludge storage tank and acid fermentation is performed to further solubilize the sludge. An experiment was conducted on the relationship between ORP) and the degree of sludge liquefaction. In this experiment, surplus sludge (sludge concentration 1.1%) generated in sewage treatment is liquefied with a 200 W ultrasonic oscillator in an ultrasonic treatment tank, and then anaerobic in a sludge storage tank (acid fermentation tank). The sludge was stored in the state and stirred while measuring the ORP. Table 19 shows the excess sludge before ultrasonic treatment, the sludge after ultrasonic treatment, and the properties of the sludge after stirring for a certain time in the storage tank.
Figure 2004005199
From Table 19, it can be seen that the soluble nitrogen increased as the ORP in the storage tank decreased, and the sludge liquefaction progressed. The dissolved Kjeldahl nitrogen reached 97 mg / L in 18 hours of stirring when the ORP was -186 mV, and the liquefaction rate with respect to untreated sludge was 14%. From this result, it is considered that the ORP serves as a guideline for determining the optimum stirring time (storage time) in the storage tank (acid fermentation tank). In the present invention, “liquefaction rate with respect to untreated sludge” means a ratio of the solid content in the sludge changed to a soluble component (a component that can pass through a filter paper having a pore diameter of 1 μm) by the liquefaction treatment. It is calculated by a formula.
Figure 2004005199

実施例8として、図26に示す装置を用いて有機性廃水の生物処理プロセスより発生した余剰汚泥を、超音波処理と貯留槽での酸発酵処理の組み合わせにより液化する実験を行なった。本実施例8での汚泥貯留槽51の汚泥滞留時間は2日に設定した。超音波発振器としては、消費電力が700W、発振周波数20kHzのものを用いた。超音波処理装置は1日あたり3.1時間運転したが、この時の超音波処理の消費電力は2.2kWhであった。
本実施例8では、原水1として下水を用いた。生物処理槽としては、脱窒槽8aと硝化槽8bを有する循環式の硝化脱窒槽により原水の生物処理を行った。原水1を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8b内の活性汚泥濃度は3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液は沈殿池9に供給して、処理水2と沈殿汚泥3に分離した。なお、硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。沈殿汚泥の一部(0.4m/d)を汚泥濃縮機10で重力濃縮により汚泥濃度2%まで濃縮した。沈殿汚泥の残りは脱窒槽8aに返送した。汚泥濃縮機10で得られた濃縮汚泥4は、超音波処理槽11に供給して超音波処理を行なった。超音波処理後の汚泥5は、汚泥貯留槽51に供給して、嫌気条件下で2日間滞留させた。汚泥貯留槽51でのORPを測定したところ、平均で−317mVであり、常時−200mV以下であった。貯留後の汚泥(貯留汚泥)52は脱窒槽8aに返送した。
表20に、本実施例8における濃縮汚泥4、超音波処理後の汚泥5、貯留後の汚泥52の性状を示す。表20より、超音波処理と貯留を行うことで溶解性成分が増加しており、汚泥が液化したことが分かる。また、貯留汚泥の有機酸を分析したところ酢酸の生成が確認された。

Figure 2004005199
表21に、実施例8の余剰汚泥処理を組合わせた場合の生物処理システムにおける処理水2の水質を示す。表21より、本実施例8では、SSが10mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができたことが分かる。
Figure 2004005199
図27に、本実施例8の余剰汚泥処理を組合わせた場合の生物処理システムにおける生物処理槽(脱窒槽8aと消化槽8b)内の合計汚泥量の経過を示す。本実施例では、余剰汚泥の排水をせずに連続運転を約60日間行ったが、汚泥量は約9kgで安定しており、余剰汚泥の発生量を抑制することができたことが分かる。返送汚泥に対して超音波処理/貯留を行わない対照系では、汚泥発生量を求めたところ1日あたり約0.7kgの余剰汚泥が発生しており、超音波処理/貯留により余剰汚泥の発生量を抑制することができたことが分かる。As Example 8, an experiment was performed to liquefy excess sludge generated from the biological treatment process of organic wastewater by a combination of ultrasonic treatment and acid fermentation treatment in a storage tank using the apparatus shown in FIG. The sludge residence time in the sludge storage tank 51 in Example 8 was set to 2 days. As the ultrasonic oscillator, one having a power consumption of 700 W and an oscillation frequency of 20 kHz was used. The ultrasonic processing apparatus was operated for 3.1 hours per day, and the power consumption of the ultrasonic processing at this time was 2.2 kWh.
In Example 8, sewage was used as the raw water 1. As a biological treatment tank, biological treatment of raw water was performed by a circulation type nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. A part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. Part of the precipitated sludge (0.4 m 3 / d) was concentrated to a sludge concentration of 2% by gravity concentration using the sludge concentrator 10. The remainder of the precipitated sludge was returned to the denitrification tank 8a. The concentrated sludge 4 obtained by the sludge concentrator 10 was supplied to the ultrasonic treatment tank 11 and subjected to ultrasonic treatment. The sludge 5 after the ultrasonic treatment was supplied to the sludge storage tank 51 and retained for 2 days under anaerobic conditions. When the ORP in the sludge storage tank 51 was measured, it was -317 mV on average and was always -200 mV or less. The sludge after storage (storage sludge) 52 was returned to the denitrification tank 8a.
Table 20 shows the properties of the concentrated sludge 4, the sludge 5 after ultrasonic treatment, and the sludge 52 after storage in Example 8. From Table 20, it can be seen that the soluble components are increased by performing ultrasonic treatment and storage, and sludge is liquefied. Moreover, when the organic acid of the stored sludge was analyzed, the production of acetic acid was confirmed.
Figure 2004005199
Table 21 shows the quality of the treated water 2 in the biological treatment system when the surplus sludge treatment of Example 8 is combined. From Table 21, it can be seen that in Example 8, it was possible to obtain good treated water quality with SS of 10 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
FIG. 27 shows the progress of the total amount of sludge in the biological treatment tank (denitrification tank 8a and digestion tank 8b) in the biological treatment system when the surplus sludge treatment of Example 8 is combined. In this example, continuous operation was performed for about 60 days without draining excess sludge, but the amount of sludge was stable at about 9 kg, indicating that the amount of excess sludge generated could be suppressed. In the control system that does not perform ultrasonic treatment / storage on the returned sludge, the amount of sludge generation was calculated, and about 0.7 kg of excess sludge was generated per day, and generation of excess sludge by ultrasonic treatment / storage. It can be seen that the amount could be suppressed.

余剰汚泥を、汚泥貯留槽で嫌気状態で貯留した後に超音波処理を行なう場合の汚泥貯留槽のORPと汚泥の液化状態の関係について実験を行った。この実験では、下水処理で発生した余剰汚泥を汚泥濃度2%まで濃縮したのち、汚泥貯留槽内で35℃に保温してORPを測定しながら撹拌した。また、撹拌48時間後の汚泥を200Wの超音波発振器で超音波処理した後、汚泥の溶解性成分窒素を測定した。結果を表22に示す。

Figure 2004005199
表22より、貯留槽内でのORPが低下するにしたがって溶解性窒素が増加しており汚泥の液化が進んだことが分かる。ORPが−195mVになった撹拌24時間で溶解性ケルダール窒素が110mg/Lであり、未処理汚泥に対する液化率が8.2%になった。さらに撹拌後の汚泥を超音波処理したところ、液化率は約19%に達した。この結果から、ORPが貯留槽(酸発酵槽)での撹拌時間(滞留時間)を決定する目安になると考えられる。An experiment was conducted on the relationship between the ORP of the sludge storage tank and the liquefaction state of the sludge when ultrasonic treatment was performed after the excess sludge was stored in an anaerobic state in the sludge storage tank. In this experiment, after surplus sludge generated in the sewage treatment was concentrated to a sludge concentration of 2%, it was kept at 35 ° C. in a sludge storage tank and stirred while measuring ORP. Further, the sludge after 48 hours of stirring was subjected to ultrasonic treatment with a 200 W ultrasonic oscillator, and then the soluble component nitrogen of the sludge was measured. The results are shown in Table 22.
Figure 2004005199
From Table 22, it can be seen that the soluble nitrogen increased as the ORP in the storage tank decreased, and sludge liquefaction progressed. The dissolved Kjeldahl nitrogen was 110 mg / L in 24 hours of stirring when the ORP was -195 mV, and the liquefaction rate with respect to the untreated sludge was 8.2%. Furthermore, when the sludge after stirring was subjected to ultrasonic treatment, the liquefaction rate reached about 19%. From this result, it is considered that the ORP serves as a guideline for determining the stirring time (residence time) in the storage tank (acid fermentation tank).

図28に示す装置を用いて、有機性廃水の生物処理プロセスより発生した余剰汚泥を、嫌気状態で貯留した後に超音波処理により液化する実験を行なった。本実施例10では、汚泥貯留槽15での汚泥滞留時間は2日に設定した。超音波処理槽11に設ける超音波発振機としては、消費電力が700W、発振周波数20kHzのものを用いた。超音波処理装置は、1日あたり3.1時間運転し、この時の超音波処理の消費電力は2.2kWhであった。
実施例10では原水1として下水を用いた。生物処理槽として、脱窒槽8aと硝化槽8bを有する循環式の硝化脱窒槽により原水の生物処理を行った。原水1を流量10m/dで脱窒槽8aに供給し、次に硝化槽8bで処理した。脱窒槽8aと硝化槽8bの活性汚泥濃度は、約3000mg−SS/Lであった。硝化槽8bから排出される活性汚泥混合液は沈殿池9に供給して、処理水2と沈殿汚泥3に分離した。硝化槽8bから排出される活性汚泥混合液の一部(原水水量の200%)を脱窒槽8aに返送した。沈殿汚泥3の流量は4m/d、汚泥濃度は約10000mg−SS/Lであった。沈殿汚泥の汚泥の一部(0.4m/d)を汚泥濃縮機10で重力濃縮により汚泥濃度2%まで濃縮した。沈殿汚泥の残りは脱窒槽8aに返送した。汚泥濃縮機10で得られた濃縮汚泥4を、汚泥貯留槽51に供給し、嫌気状態で貯留した。汚泥貯留槽51での汚泥の滞留時間は2日間とした。汚泥貯留槽51でのORPを測定したところ、平均で−317mVであり、常時−200mV以下であった。貯留後の汚泥52は超音波反応槽11で超音波処理した後、脱窒槽8aに返送した。
表23に、本実施例10における濃縮汚泥4、貯留汚泥52、超音波処理汚泥5の性状を示す。表23より、汚泥の貯留と超音波処理を行うことで溶解性成分が増加しており、汚泥が液化したことが分かる。また、貯留汚泥の有機酸を分析したところ酢酸の生成が確認された。

Figure 2004005199
表24に、実施例10の余剰汚泥処理を組合わせた場合の生物処理システムにおける処理水2の水質を示す。表24より、本実施例10では、SSが10mg/L、CODCrも30mg/Lの良好な処理水水質を得ることができたことが分かる。
Figure 2004005199
本実施例10での生物処理槽(脱窒槽8aと硝化槽8b)内の合計汚泥量の経過は、実施例8と同様であった。Using the apparatus shown in FIG. 28, an experiment was conducted in which excess sludge generated from the biological treatment process of organic waste water was liquefied by ultrasonic treatment after being stored in an anaerobic state. In the present Example 10, the sludge residence time in the sludge storage tank 15 was set to 2 days. As the ultrasonic oscillator provided in the ultrasonic treatment tank 11, one having a power consumption of 700 W and an oscillation frequency of 20 kHz was used. The ultrasonic processing apparatus was operated for 3.1 hours per day, and the power consumption of the ultrasonic processing at this time was 2.2 kWh.
In Example 10, sewage was used as the raw water 1. As a biological treatment tank, the raw water was biologically treated by a circulating nitrification denitrification tank having a denitrification tank 8a and a nitrification tank 8b. The raw water 1 was supplied to the denitrification tank 8a at a flow rate of 10 m 3 / d and then treated in the nitrification tank 8b. The activated sludge concentration in the denitrification tank 8a and the nitrification tank 8b was about 3000 mg-SS / L. The activated sludge mixed liquid discharged from the nitrification tank 8b was supplied to the settling basin 9 and separated into the treated water 2 and the precipitated sludge 3. Part of the activated sludge mixed liquid discharged from the nitrification tank 8b (200% of the amount of raw water) was returned to the denitrification tank 8a. The flow rate of the precipitated sludge 3 was 4 m 3 / d, and the sludge concentration was about 10,000 mg-SS / L. Part of the sludge (0.4 m 3 / d) of the precipitated sludge was concentrated to a sludge concentration of 2% by gravity concentration using the sludge concentrator 10. The remainder of the precipitated sludge was returned to the denitrification tank 8a. The concentrated sludge 4 obtained by the sludge concentrator 10 was supplied to the sludge storage tank 51 and stored in an anaerobic state. The sludge residence time in the sludge storage tank 51 was 2 days. When the ORP in the sludge storage tank 51 was measured, it was -317 mV on average and was always -200 mV or less. The stored sludge 52 was subjected to ultrasonic treatment in the ultrasonic reaction tank 11 and then returned to the denitrification tank 8a.
Table 23 shows the properties of the concentrated sludge 4, the stored sludge 52, and the sonicated sludge 5 in Example 10. From Table 23, it turns out that the soluble component has increased by performing sludge storage and ultrasonic treatment, and the sludge has been liquefied. Moreover, when the organic acid of the stored sludge was analyzed, the production of acetic acid was confirmed.
Figure 2004005199
Table 24 shows the quality of the treated water 2 in the biological treatment system when the surplus sludge treatment of Example 10 is combined. From Table 24, it can be seen that in Example 10, it was possible to obtain good treated water quality with SS of 10 mg / L and COD Cr of 30 mg / L.
Figure 2004005199
The progress of the total sludge amount in the biological treatment tank (denitrification tank 8a and nitrification tank 8b) in Example 10 was the same as in Example 8.

産業上の利用の可能性Industrial applicability

本発明によれば、有機性廃水の生物処理プロセスにおいて発生する余剰汚泥を可溶化させるにあたって、超音波処理と、酸発酵処理、化学処理及び加温処理の少なくとも一つとの組み合わせによって処理することにより、少ないエネルギー量で格段に液化効率を高めて、余剰汚泥の発生量を減少させることができる。  According to the present invention, in solubilizing excess sludge generated in the biological treatment process of organic wastewater, by treating with a combination of ultrasonic treatment and at least one of acid fermentation treatment, chemical treatment and heating treatment. The liquefaction efficiency can be significantly increased with a small amount of energy, and the amount of excess sludge generated can be reduced.

Claims (38)

生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥の処理方法であって、前記余剰汚泥の一部又は全量を、超音波処理と、酸発酵処理、化学処理及び加温処理の少なくとも一つとの組み合わせによって可溶化処理し、可溶化処理された汚泥を生物処理工程に返送することを特徴とする方法。A method for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, wherein a part or all of the surplus sludge is subjected to ultrasonic treatment, acid fermentation treatment, chemical A method comprising solubilizing by combination with at least one of treatment and heating treatment, and returning the solubilized sludge to the biological treatment step. 汚泥の化学処理が、オゾン、過酸化水素、酸化剤及びアルカリ剤のいずれかによって汚泥を処理するものである請求項1に記載の方法。The method according to claim 1, wherein the chemical treatment of sludge is a treatment of sludge with any one of ozone, hydrogen peroxide, an oxidizing agent, and an alkaline agent. 前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is sonicated, the sonicated sludge is then subjected to acid fermentation, and the acid-fermented sludge is returned to the biological treatment process. 前記余剰汚泥の一部又は全量を酸発酵処理し、酸発酵処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is subjected to an acid fermentation treatment, the acid fermentation treatment sludge is then subjected to ultrasonic treatment, and the ultrasonically treated sludge is returned to the biological treatment step. 前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に化学処理して、化学処理された汚泥を生物処理工程に返送する請求項1又は2に記載の方法。The method according to claim 1 or 2, wherein a part or all of the excess sludge is sonicated, the sonicated sludge is then chemically treated, and the chemically treated sludge is returned to the biological treatment step. 前記余剰汚泥の一部又は全量を化学処理し、化学処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する請求項1又は2に記載の方法。The method according to claim 1 or 2, wherein a part or all of the excess sludge is chemically treated, the chemically treated sludge is then sonicated, and the sonicated sludge is returned to the biological treatment step. 前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に加温処理し、加温処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is sonicated, the sonicated sludge is then heated, and the heated sludge is returned to the biological treatment process. 前記余剰汚泥の一部又は全量を加温処理し、加温処理汚泥を次に超音波処理して、超音波処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is heated, the heated sludge is then sonicated, and the sonicated sludge is returned to the biological treatment step. 前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に加温処理し、加温処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The surplus sludge is partly or wholly sonicated, the sonicated sludge is then warmed, the warmed sludge is then acid-fermented, and the acid-fermented sludge is subjected to a biological treatment process. The method of claim 1, wherein the method is returned. 前記余剰汚泥の一部又は全量を加温処理し、加温処理汚泥を次に超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する請求項1に記載の方法。A part or all of the excess sludge is heated, the heated sludge is then subjected to ultrasonic treatment, the ultrasonically treated sludge is then subjected to acid fermentation treatment, and the acid-fermented sludge is subjected to a biological treatment process. The method of claim 1, wherein the method is returned. 前記余剰汚泥の一部又は全量を超音波処理し、超音波処理汚泥を次に化学処理し、化学処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する請求項1又は2に記載の方法。A part or all of the excess sludge is sonicated, the sonicated sludge is then chemically treated, the chemically treated sludge is then acid fermented, and the acid-fermented sludge is returned to the biological treatment process. The method according to claim 1 or 2. 前記余剰汚泥の一部又は全量を化学処理し、化学処理汚泥を次に超音波処理し、超音波処理汚泥を次に酸発酵処理して、酸発酵処理された汚泥を生物処理工程に返送する請求項1又は2に記載の方法。A part or all of the excess sludge is chemically treated, the chemically treated sludge is then sonicated, the sonicated sludge is then acid fermented, and the acid-fermented sludge is returned to the biological treatment process. The method according to claim 1 or 2. 前記余剰汚泥の一部又は全量を、超音波発信機を備えた酸発酵槽において酸発酵しながら超音波処理して、処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is subjected to ultrasonic treatment while acid fermentation in an acid fermentation tank equipped with an ultrasonic transmitter, and the treated sludge is returned to the biological treatment step. 前記余剰汚泥の一部又は全量を、超音波発信機を備えた加温槽において加温しながら超音波処理して、処理された汚泥を生物処理工程に返送する請求項1に記載の方法。The method according to claim 1, wherein a part or all of the excess sludge is ultrasonically treated while being heated in a heating tank equipped with an ultrasonic transmitter, and the treated sludge is returned to the biological treatment step. 酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、酸発酵処理での汚泥の水力学的滞留時間を制御する請求項1,2,3,4,9,10,11,12又は13のいずれかに記載の方法。The hydrodynamic residence time of sludge in acid fermentation treatment is controlled so that the oxidation-reduction potential of sludge in acid fermentation treatment is -100 mV or less. 14. The method according to any one of 12 and 13. 酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、有機性廃水の一部を直接酸発酵処理に供給する請求項1,2,3,4,9,10,11,12又は13のいずれかに記載の方法。A portion of the organic waste water is directly supplied to the acid fermentation treatment so that the oxidation-reduction potential of the sludge in the acid fermentation treatment is -100 mV or less. 1, 2, 3, 4, 9, 10, 11, 12 Or the method in any one of 13. 酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、酸発酵処理された汚泥の一部を超音波処理に返送する請求項1,2,3,9,10又は12のいずれかに記載の方法。Any one of claims 1, 2, 3, 9, 10 or 12 for returning a part of the sludge subjected to acid fermentation treatment to ultrasonic treatment so that the oxidation-reduction potential of sludge in the acid fermentation treatment is -100 mV or less. The method of crab. 酸発酵処理での汚泥の酸化還元電位が−100mV以下になるように、超音波処理された汚泥の一部を酸発酵処理に返送する請求項1,2又は4のいずれかに記載の方法。The method according to any one of claims 1, 2 and 4, wherein a part of the sludge subjected to ultrasonic treatment is returned to the acid fermentation treatment so that the oxidation-reduction potential of the sludge in the acid fermentation treatment is -100 mV or less. 余剰汚泥の一部又は全量を、汚泥濃度で1〜10重量%に濃縮し、濃縮した汚泥を前記可溶化処理する請求項1〜18のいずれかに記載の方法。The method according to any one of claims 1 to 18, wherein a part or all of the excess sludge is concentrated to 1 to 10% by weight in terms of a sludge concentration, and the concentrated sludge is subjected to the solubilization treatment. 有機性廃水を生物処理槽で生物処理し、生物処理槽から排出される活性汚泥混合液を固液分離して、沈殿汚泥と処理水とを生成させ、前記沈殿汚泥を余剰汚泥としてその一部又は全量を請求項1〜19のいずれかに規定する可溶化処理にかけて処理汚泥を生物処理槽に返送することを特徴とする有機性廃水の処理方法。Organic wastewater is biologically treated in a biological treatment tank, the activated sludge mixed liquid discharged from the biological treatment tank is solid-liquid separated to generate precipitated sludge and treated water, and the precipitated sludge is used as excess sludge. Alternatively, the treatment method of organic wastewater is characterized in that the treatment sludge is returned to the biological treatment tank through the solubilization treatment specified in any one of claims 1 to 19. 有機性廃水を生物処理槽で生物処理し、生物処理槽から排出される活性汚泥混合液を固液分離して、沈殿汚泥と処理水とを生成させ、前記沈殿汚泥を余剰汚泥としてその一部又は全量を汚泥濃度で1〜10重量%に濃縮し、濃縮した汚泥を請求項1〜19のいずれかに規定する可溶化処理にかけて処理汚泥を生物処理槽に返送することを特徴とする有機性廃水の処理方法。Organic wastewater is biologically treated in a biological treatment tank, the activated sludge mixed liquid discharged from the biological treatment tank is solid-liquid separated to generate precipitated sludge and treated water, and the precipitated sludge is used as excess sludge. Or the whole quantity is concentrated to 1 to 10 weight% by sludge density | concentration, the treated sludge is returned to a biological treatment tank through the solubilization process prescribed | regulated in any one of Claims 1-19, The organic property characterized by the above-mentioned. Wastewater treatment method. 生物処理工程と固液分離工程で構成される有機性廃水の処理プロセスから発生する余剰汚泥を処理するための装置であって、前記余剰汚泥の一部又は全量を可溶化処理するための装置と、前記可溶化処理装置で処理された汚泥を生物処理工程へ返送するための配管を具備し、前記可溶化処理装置が、超音波処理装置と、酸発酵処理装置、化学処理装置及び加温処理装置の少なくとも一つとの組み合わせによって構成されることを特徴とする装置。An apparatus for treating surplus sludge generated from a treatment process of organic wastewater composed of a biological treatment step and a solid-liquid separation step, and a device for solubilizing a part or all of the surplus sludge; And a pipe for returning the sludge treated in the solubilization treatment apparatus to the biological treatment process, and the solubilization treatment apparatus comprises an ultrasonic treatment apparatus, an acid fermentation treatment apparatus, a chemical treatment apparatus, and a heating treatment. A device comprising a combination with at least one of the devices. 汚泥の可溶化処理装置が、オゾン、過酸化水素、酸化剤及びアルカリ剤のいずれかを用いる化学処理装置である請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization treatment apparatus is a chemical treatment apparatus using any one of ozone, hydrogen peroxide, an oxidizing agent, and an alkaline agent. 汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus is composed of an ultrasonic treatment apparatus for ultrasonically treating the sludge and an acid fermentation apparatus for subjecting the ultrasonic treatment sludge to an acid fermentation treatment. 汚泥の可溶化処理装置が、汚泥を酸発酵処理する酸発酵装置と、酸発酵処理汚泥を超音波処理する超音波処理装置とにより構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus includes an acid fermentation apparatus that performs acid fermentation treatment on sludge and an ultrasonic treatment apparatus that performs ultrasonic treatment on the acid fermentation treatment sludge. 汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を化学処理する化学処理装置とにより構成される請求項22又は23に記載の装置。24. The apparatus according to claim 22 or 23, wherein the sludge solubilization treatment apparatus comprises an ultrasonic treatment apparatus for ultrasonically treating sludge and a chemical treatment apparatus for chemically treating ultrasonic treatment sludge. 汚泥の可溶化処理装置が、汚泥を化学処理する化学処理装置と、化学処理汚泥を超音波処理する超音波処理装置とにより構成される請求項22又は23に記載の装置。24. The apparatus according to claim 22 or 23, wherein the sludge solubilization treatment apparatus comprises a chemical treatment apparatus for chemically treating sludge and an ultrasonic treatment apparatus for ultrasonically treating the chemically treated sludge. 汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を加温処理する加温処理装置とにより構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus includes an ultrasonic treatment apparatus for ultrasonically treating the sludge and a heating treatment apparatus for heating the ultrasonicated sludge. 汚泥の可溶化処理装置が、汚泥を加温処理する加温処理装置と、加温処理汚泥を超音波処理する超音波処理装置とにより構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus is constituted by a heating processing apparatus that heats sludge and an ultrasonic processing apparatus that ultrasonically processes the heating sludge. 汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を加温処理する加温処理装置と、加温処理汚泥を酸発酵処理する酸発酵装置とにより構成される請求項22に記載の装置。The sludge solubilization treatment apparatus is composed of an ultrasonic treatment apparatus for ultrasonically treating sludge, a heating treatment apparatus for heating ultrasonic treatment sludge, and an acid fermentation apparatus for subjecting the heated sludge to acid fermentation treatment. 23. The apparatus of claim 22, wherein: 汚泥の可溶化処理装置が、汚泥を加温処理する加温処理装置と、加温処理汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される請求項22に記載の装置。The sludge solubilization treatment device comprises a heating treatment device that heats sludge, an ultrasonic treatment device that ultrasonically treats the heated sludge, and an acid fermentation device that performs acid fermentation treatment on the ultrasonic treatment sludge. 23. The apparatus of claim 22, wherein: 汚泥の可溶化処理装置が、汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を化学処理する化学処理装置と、化学処理汚泥を酸発酵処理する酸発酵装置とにより構成される請求項22又は23に記載の装置。Claims wherein the sludge solubilization treatment device comprises an ultrasonic treatment device for ultrasonically treating sludge, a chemical treatment device for chemically treating ultrasonic treatment sludge, and an acid fermentation device for subjecting chemical treatment sludge to acid fermentation treatment. Item 24. The apparatus according to Item 22 or 23. 汚泥の可溶化処理装置が、汚泥を化学処理する化学処理装置と、化学処理汚泥を超音波処理する超音波処理装置と、超音波処理汚泥を酸発酵処理する酸発酵装置とにより構成される請求項22又は23に記載の装置。Claims wherein the sludge solubilization treatment apparatus comprises a chemical treatment apparatus for chemically treating sludge, an ultrasonic treatment apparatus for ultrasonically treating the chemically treated sludge, and an acid fermentation apparatus for subjecting the ultrasonic treatment sludge to an acid fermentation treatment. Item 24. The apparatus according to Item 22 or 23. 汚泥の可溶化処理装置が、超音波発信機を備えた酸発酵槽により構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus is constituted by an acid fermentation tank equipped with an ultrasonic transmitter. 汚泥の可溶化処理装置が、超音波発信機を備えた加温槽により構成される請求項22に記載の装置。The apparatus according to claim 22, wherein the sludge solubilization apparatus is constituted by a heating tank provided with an ultrasonic transmitter. 余剰汚泥の一部又は全量を受容して汚泥を濃縮する濃縮装置と、濃縮装置から排出される濃縮汚泥を前記可溶化処理装置に供給する配管とを更に具備する請求項22〜35のいずれかに記載の装置。36. The apparatus according to any one of claims 22 to 35, further comprising a concentrating device that receives a part or all of the excess sludge and concentrates the sludge, and a pipe that supplies the solubilized processing device with the concentrated sludge discharged from the concentrating device. The device described in 1. 有機性廃水を受容して生物処理を行なう生物処理槽、前記生物処理槽から排出される活性汚泥混合液を固液分離して沈殿汚泥と処理水とを生成させる固液分離装置、請求項22〜36のいずれかに規定する汚泥可溶化処理装置、前記固液分離装置から排出される沈殿汚泥の一部又は全量を前記汚泥可溶化処理装置に供給する配管、可溶化処理装置から排出される処理汚泥を生物処理槽に返送する配管を、具備することを特徴とする有機性廃水の処理装置。23. A biological treatment tank that receives organic wastewater and performs biological treatment, and a solid-liquid separation device that generates a precipitated sludge and treated water by solid-liquid separation of an activated sludge mixed liquid discharged from the biological treatment tank. The sludge solubilization treatment device defined in any one of -36, a pipe for supplying a part or all of the precipitated sludge discharged from the solid-liquid separation device to the sludge solubilization treatment device, and the solubilization treatment device. An organic wastewater treatment apparatus comprising a pipe for returning treated sludge to a biological treatment tank. 有機性廃水を受容して生物処理を行なう生物処理槽、前記生物処理槽から排出される活性汚泥混合液を固液分離して沈殿汚泥と処理水とを生成させる固液分離装置、前記固液分離装置から排出される沈殿汚泥の一部又は全量を受容して汚泥を濃縮する濃縮装置、請求項22〜36のいずれかに規定する汚泥可溶化処理装置、濃縮装置から排出される濃縮汚泥を前記可溶化処理装置に供給する配管、可溶化処理装置から排出される処理汚泥を生物処理槽に返送する配管、を具備することを特徴とする有機性廃水の処理装置。A biological treatment tank that receives organic wastewater and performs biological treatment, a solid-liquid separation device that produces a precipitated sludge and treated water by solid-liquid separation of the activated sludge mixed liquid discharged from the biological treatment tank, and the solid-liquid separation 37. A concentrating device that receives a part or all of the precipitated sludge discharged from the separator and concentrates the sludge, the sludge solubilizing device defined in any of claims 22 to 36, and the concentrated sludge discharged from the concentrating device. An organic wastewater treatment apparatus comprising: a pipe for supplying to the solubilization treatment apparatus; and a pipe for returning treated sludge discharged from the solubilization treatment apparatus to a biological treatment tank.
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