JP3565308B2

JP3565308B2 - Organic wastewater treatment method and equipment

Info

Publication number: JP3565308B2
Application number: JP33085697A
Authority: JP
Inventors: 光市桐山; 昭渡辺; 信和木幡
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 1997-11-17
Filing date: 1997-11-17
Publication date: 2004-09-15
Anticipated expiration: 2017-11-17
Also published as: JPH11147100A

Description

【０００１】
【発明の属する技術分野】
本発明は、有機性汚水の処理方法に係り、特に、有機性汚水を好気性生物処理して得られる余剰汚泥を可溶化する処理方法と装置に関する。
【０００２】
【従来の技術】
従来、有機性汚水の好気性生物処理（活性汚泥法、生物学的硝化脱窒素法など）の最大の問題点は、水質を浄化する工程に存在するのではなく、むしろ汚泥処理工程にある。
すなわち、好気性生物処理方法は、余剰活性汚泥の発生量が非常に多い点に最大の問題点がある。余剰活性汚泥は、現在脱水後、埋立てあるいは焼却処分されているが、多大の経費と設備を必要としていた。
従来の活性汚泥法の余剰汚泥の発生量は、数多くの実験あるいは実績により、除去ＢＯＤ当り、０．６〜０．８（ｋｇＳＳ／ｋｇＢＯＤ）程度となることが良く知られている。その上、余剰汚泥は、質的にも難脱水性であるため、益々汚泥処理が困難になっている。
このような、余剰汚泥を減少するために、従来余剰汚泥の可溶化処理方法として、アルカリ剤を添加して処理する方法（特開平２−２２７１９０号公報参照）、一方にアルカリ剤、片方に酸を添加して処理する方法（特開平２−２９３０９５号公報）等が知られていたが、これらの処理方法でも余剰汚泥はある程度減少するものの、より以上の減容化方法が望まれていた。
【０００３】
【発明が解決しようとする課題】
本発明は、上記従来技術に鑑み、簡単な処理手段により余剰汚泥のほとんど発生しない、有機性汚水の好気性生物処理方法と装置を提供することを課題とする。
【０００４】
【課題を解決するための手段】
上記課題を解決するために、本発明では、有機性汚水を好気性生物処理した後、得られる汚泥の一部を可溶化処理して前記好気性生物処理工程に戻して処理する方法において、前記可溶化処理が、酸性酸化剤を用いる酸性酸化処理工程及びアルカリ剤を用いるアルカリ処理工程と、超音波処理工程とを組合せて成り、前記酸性酸化剤及びアルカリ剤が、塩水を隔膜電解して得られた酸性酸化水及びアルカリ水であることを特徴とする有機性汚水の処理方法としたものである。
前記処理方法において、酸性酸化処理工程及びアルカリ処理工程は、並列又は直列に設けられ、それぞれ単独又は複数の工程から成り、かつ、この一連の酸・アルカリ処理工程の前、又は後に超音波処理工程が設けられるか、又は、アルカリ処理工程の後に超音波処理工程が直列に設けられる。
【０００５】
また、前記酸性酸化処理工程とアルカリ処理工程が、それぞれ複数の工程から成り、該複数の工程から成る酸性酸化処理工程及びアルカリ処理工程では、該工程の前段の工程に酸性酸化剤又はアルカリ剤を全量導入するとともに、被処理汚泥を各段の工程に分配して導入するのがよい。
また、前記可溶化処理した汚泥は、好気性生物処理工程に戻す前に前曝気工程を設けて曝気処理して残留塩素を揮発除去するのが良く、さらに、該汚泥の一部は、再度可溶化処理する工程に戻して処理することにより、より分解性は向上する。
また、本発明では、有機性汚水を好気性生物処理する生物処理槽と、生物処理した処理液を固液分離する固液分離装置と、固液分離した汚泥の一部を可溶化処理する可液化処理手段と、可溶化処理した処理液を前記好気性生物処理槽に戻す流路とを有する有機性汚水の処理装置において、前記可溶化処理手段が、酸性酸化剤を用いる酸性酸化処理槽及びアルカリ剤を用いるアルカリ処理槽と、超音波処理を行う超音波発振子と、前記酸性酸化処理槽及びアルカリ処理槽に酸性酸化剤とアルカリ剤を供給する塩水の隔膜電解装置とから成ることを特徴とする有機性汚水の処理装置としたものである。
なお、可溶化処理で酸性酸化処理工程及びアルカリ処理工程で処理した汚泥は、これらを混合することにより中性に戻すが、万一ｐＨが中性域を外れた場合は、酸性酸化水又はアルカリ水を用いて中性に戻すのが良い。
【０００６】
【発明の実施の形態】
次に、図面を用いて本発明を詳細に説明する。
図１に、本発明の処理方法の汚泥減容化プロセスのフローの一例を示す。
図１においては、有機性汚水１２を、好気性生物処理槽１で処理し、沈殿槽２で固液分離して処理水１３と汚泥１４、１５を得る排水処理工程で処理し、発生した汚泥の一部を返送汚泥１４として生物処理槽１に循環すると共に、他部１５を可溶化工程３に導入して、汚泥を可溶化及び分解処理を行った後、排水処理工程の生物処理槽１に返送１８して、溶解性有機物及び汚泥分の生物分解を行っている。
可溶化工程３に導入された汚泥１５は、並列で複数（２槽づつ）設けられたアルカリ処理工程５、５′と酸化処理工程４、４′にそれぞれ導入され、海水又は塩素イオンを含む各種の塩水を隔膜電解して得られたアルカリ水２１及び酸性酸化水２０と接触させることにより、可溶化及び酸化分解処理を行っている。そして、アルカリ処理工程では、５′の後で、酸化処理工程終了汚泥と混合する前に、超音波処理２４が導入される。
【０００７】
塩水の隔膜電解は、隔膜１１によって陽極９を有する陽極室７と陰極１０を有する陰極室８によって仕切られた隔膜電解装置６を用いて行い、該装置６の陽極室７と陰極室８に塩水１９を導入する。陽極室７では、陽極でＨ^＋が生成し、酸性になると共に、塩水中のＣｌ⁻より塩素系酸化剤（ＨＣｌＯ、Ｃｌ_２、Ｃｌ・等）が発生し、酸性酸化水２０を得、陰極室８では、陰極でＯＨ⁻が生成しアルカリ性になり、アルカリ水２１を得て、酸性酸化水２０を酸化槽４に、アルカリ水２１をアルカリ槽５にそれぞれ導入して可溶化処理に用いる。
また、アルカリ処理工程と酸化処理工程は、それぞれ処理槽を２段に設け、それぞれに導入された汚泥１６、１７の一部は、第２アルカリ槽５′と第２酸化槽４′にそれぞれ分流して導入する。そして、第２アルカリ処理５′の後に続いて、超音波処理を受ける。超音波の出力は、アルカリ処理工程導入汚泥の量や、超音波との接触時間によって決定されるが、周波数は低い方が好ましい。超音波処理の態様は、図２に示されるように、下部に超音波発振子が並べられているアルカリ槽に所定時間、アルカリ処理汚泥を貯留せしめる方法でもよく、また、図３に示されるように、アルカリ槽において汚泥をポンプ循環し、当該循環用配管内に超音波発振子を挿入する方法でもよい。
【０００８】
次に、これらの槽の作用を説明する。
まず、第１アルカリ槽は、隔膜電解により生成したアルカリを汚泥に反応させ、強アルカリ条件下で、汚泥菌体の破壊及び細胞内液の溶出による汚泥の可溶化処理を行い、第２アルカリ槽は、第１アルカリ槽からの余剰アルカリを利用して、汚泥の減容化を進行させる。更に続いて、超音波処理することにより、第１アルカリ槽にて十分に破壊されなかった汚泥菌体が破壊され、汚泥の減容化を一段と進んだものにする。
次に、第１酸化槽は、隔膜電解により生成した酸、酸化剤を汚泥に反応させ、強酸条件下で汚泥菌体の酸化分解処理を行い、第２酸化槽は、第１酸化槽からの余剰の酸、酸化剤を利用して、汚泥の酸化分解を進行させる。
なお、図１では、アルカリ処理及び酸性酸化処理を並列でそれぞれ２系列で行っているが、各々の処理は、単一槽（第１アルカリ槽と第１酸化槽のみ）でも良いし、それぞれを２槽以上の系列で行ってもよい。
【０００９】
図４に、本発明の処理方法の別の概略フロー工程図を示す。図４では酸性酸化処理工程及びアルカリ処理工程から成る一連の酸・アルカリ処理の後に、超音波処理工程２４を設けている。また、図５では、超音波処理工程２４の後に、酸性酸化処理工程及びアルカリ工程から成る一連の酸・アルカリ処理工程を設けている。
図６においては、有機性汚水１２は生物処理槽１に入る前に調整槽２３に導入されて曝気処理される。また、可溶化工程３からの可溶化汚泥１８は、前曝気槽２２で曝気処理され、可溶化処理に用いた電解水中の残留塩素を揮発除去した後に、生物処理槽１に導入している。なお、前曝気槽２２の替りに、可溶化汚泥１８を調整槽２３に導入して、曝気処理して残留塩素を除去することができる。
図７に、可溶化汚泥１８の一部を、可溶化工程３に循環する概略フロー工程図を示す。このように、可溶化汚泥の一部を循環処理することにより、更に汚泥の分解性を向上することができる。
【００１０】
【実施例】
以下、本発明を実施例により具体的に説明する。
実施例１
図１の処理フローに示した実験装置（ＲＵＮ１）と、同フローから可溶化工程を除いた実験装置（ＲＵＮ２）の２系列を設けて、処理水質と汚泥発生量を比較した。ＲＵＮ１において、可溶化工程に導入する汚泥量は余剰汚泥量の４倍量とし、アルカリ処理工程には、その２／３量、酸化処理工程にはその１／３量をそれぞれ導入した。また、第２アルカリ槽には、アルカリ処理工程に導入される汚泥量の１／２量、第２酸化槽には、酸化処理工程に導入される汚泥量の１／３量をそれぞれ導入した。各処理槽の滞留時間はいずれも４時間とした。本実施例では、塩水として海水の１／２の塩分濃度の食塩水を用いた。また、食塩水の使用量は、余剰汚泥量と同量を電解処理槽に通水した。アルカリ処理工程の後の超音波処理は、周波数２０ｋＨｚ、出力２５Ｗにて１時間行った。
【００１１】
隔膜電解処理の条件と得られた電解水（アルカリ水、酸性酸化水）の性状を、表１、２にそれぞれ示す。なお、実験はＡ食品会社の排水を原水（ｐＨ６．４、ＢＯＤ５００ｍｇ／リットル、ＣＯＤＭｎ２４０ｍｇ／リットル、ＳＳ８０ｍｇ／リットル）として、ＲＵＮ１とＲＵＮ２の運転条件は可溶化工程を設ける以外は同条件で運転した。
【表１】

【表２】

【００１２】
表３に、導入汚泥と処理済汚泥の性状を示す。
【表３】

【００１３】
実験結果を表４に示す。表４から、超音波処理工程を含む可溶化工程を組み込んだＲＵＮ１はＲＵＮ２に比べて汚泥発生量が著しく少なく、処理水質もほとんど差はなかった。
【表４】

【００１４】
実施例２
図５の処理フローに示した実験装置（Ｒｕｎ３）と、同フローから可溶化工程を除いた実験装置（Ｒｕｎ４）の２系列を設けて、処理水質と汚泥発生量を比較した。ＲＵＮ３において、可溶化工程に導入する汚泥量は余剰汚泥量の４倍量とし、先ず、周波数２０ｋＨｚ、出力２００Ｗの超音波を１５分間反応させ、アルカリ処理工程には、その２／３量、酸化処理工程にはその１／３量をそれぞれ導入した。また、第２アルカリ槽には、アルカリ処理工程に導入される汚泥量の１／２量、第２酸化槽には、酸化処理工程に導入される汚泥量の１／３量をそれぞれ導入した。各処理槽の滞留時間はいずれも４時間とした。
本実施例では、塩水として海水の１／２の塩分濃度の食塩水を用いた。また、食塩水の使用量は、余剰汚泥量と同量を電解処理槽に通水した。
【００１５】
隔膜電解処理の条件と得られた電解水（アルカリ水、酸性酸化水）の性状を、表５、６にそれぞれ示す。なお、実験はＡ食品会社の排水を原水（ｐＨ６．４、ＢＯＤ５００ｍｇ／リットル、ＣＯＤＭｎ２４０ｍｇ／リットル、ＳＳ８０ｍｇ／リットル）として、ＲＵＮ３とＲＵＮ４の運転条件は可溶化工程を設ける以外は同条件で運転した。
【表５】

【表６】

【００１６】
表７に、導入汚泥と処理済汚泥の性状を示す。
【表７】

【００１７】
実験結果を表８に示す。表８から、超音波処理工程を含む可溶化工程を組み込んだＲＵＮ３はＲＵＮ４に比べて汚泥発生量が著しく少なく、処理水質もほとんど差はなかった。
【表８】

【００１８】
【発明の効果】
本発明によれば、酸性酸化剤及びアルカリ剤と超音波処理を用いた処理により、余剰汚泥をほとんど分解でき、汚泥はほとんど発生せず、また、酸性酸化剤、アルカリ剤として塩水の隔膜処理から得られる酸性酸化水、アルカリ水を用いることにより、安価に容易に得ることができる。
【図面の簡単な説明】
【図１】本発明の処理方法を用いる汚泥減容化プロセスのフロー工程図。
【図２】超音波処理方法の一例を示す概略構成図。
【図３】超音波処理方法の他の例を示す概略構成図。
【図４】本発明の他の処理方法に用いる汚泥減容化プロセスの他のフロー工程図。
【図５】本発明の他の処理方法に用いる汚泥減容化プロセスの他のフロー工程図。
【図６】本発明の処理方法に用いる他の概略フロー工程図。
【図７】本発明の処理方法に用いる他の概略フロー工程図。
【符号の説明】
１：好気性生物処理槽、２：沈殿槽、３：可溶化工程、４：第１酸化槽、４′：第２酸化槽、５：第１アルカリ槽、５′：第２アルカリ槽、６：隔膜電解装置、７：陽極室、８：陰極室、９：陽極、１０：陰極、１１：隔膜、１２：有機性汚水、１３：処理水、１４：返送汚泥、１５：余剰汚泥、１６、１７：余剰汚泥の一部、１８：可溶化汚泥、１９：塩水、２０：酸性酸化水、２１：アルカリ水、２２：前曝気槽、２３：調整槽、２４：超音波処理、２５：超音波発振子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for treating organic sewage, and more particularly to a method and apparatus for solubilizing excess sludge obtained by aerobic biological treatment of organic sewage.
[0002]
[Prior art]
Conventionally, the biggest problem of aerobic biological treatment of organic wastewater (activated sludge method, biological nitrification denitrification method, etc.) is not in the step of purifying water quality but rather in the sludge treatment step.
That is, the aerobic biological treatment method has the greatest problem in that the amount of surplus activated sludge generated is extremely large. Excess activated sludge is currently landfilled or incinerated after dehydration, but it requires a great deal of cost and equipment.
It is well known that the amount of surplus sludge generated by the conventional activated sludge method is about 0.6 to 0.8 (kgSS / kgBOD) per removed BOD, based on many experiments and results. In addition, surplus sludge is hardly dehydrated in quality, so that sludge treatment becomes more and more difficult.
In order to reduce such excess sludge, a conventional method of solubilizing excess sludge is to add an alkaline agent and treat it (see JP-A-2-227190). And the like (JP-A-2-293095) have been known. However, even with these treatment methods, excess sludge is reduced to some extent, but a further volume reduction method has been desired.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide an aerobic biological treatment method and apparatus for organic sewage, in which excess sludge is hardly generated by a simple treatment means in view of the above-mentioned conventional technology.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention, after treating organic sewage with aerobic biological treatment, a method of solubilizing a part of the obtained sludge and returning to the aerobic biological treatment step for treatment, solubilization process, the alkaline treatment step using an acidic oxidation treatment step and an alkaline agent an acidic oxidizing agent, Ri formed by combining a sonication step, the acid oxidizing agent and an alkali agent, a salt water and membrane electrolysis This is a method for treating organic sewage, characterized by being the obtained acidic oxidized water and alkaline water .
In the treatment method, the acidic oxidation treatment step and the alkali treatment step are provided in parallel or in series, each consisting of one or more steps, and before or after this series of acid / alkali treatment steps, Or an ultrasonic treatment step is provided in series after the alkali treatment step .
[0005]
Further, the acid oxidation treatment step and the alkali treatment step each comprise a plurality of steps, and in the acid oxidation treatment step and the alkali treatment step comprising the plurality of steps, an acid oxidizing agent or an alkali agent is added to the step preceding the step. It is preferable that the sludge to be treated is distributed and introduced into the processes at each stage while the entire amount is introduced.
Before returning to the aerobic biological treatment step, the solubilized sludge may be provided with a pre-aeration step to perform aeration treatment to volatilize and remove residual chlorine. By returning to the step of the solubilization treatment and performing the treatment, the decomposability is further improved.
Further, in the present invention, a biological treatment tank for aerobic biological treatment of organic wastewater, a solid-liquid separation device for solid-liquid separation of a biologically treated liquid, and a solubilization treatment for a part of solid-liquid separated sludge can be performed. Liquefaction treatment means, in an organic sewage treatment apparatus having a flow path for returning the treatment solution subjected to solubilization to the aerobic biological treatment tank, wherein the solubilization treatment means, an acid oxidation treatment tank using an acidic oxidizing agent, It is characterized by comprising an alkali treatment tank using an alkali agent, an ultrasonic oscillator for performing ultrasonic treatment, and a diaphragm electrolysis apparatus for supplying an acidic oxidant and an alkali agent to the acid oxidation treatment tank and the alkali treatment tank. Organic wastewater treatment apparatus.
The sludge treated in the acid oxidation treatment step and the alkali treatment step in the solubilization treatment is returned to neutrality by mixing these. However, if the pH is out of the neutral range, the acid sludge is treated with acidic oxidized water or alkali. It is better to return to neutrality with water.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an example of a flow of a sludge volume reduction process of the treatment method of the present invention.
In FIG. 1, an organic wastewater 12 is treated in an aerobic biological treatment tank 1, and solid-liquid separated in a sedimentation tank 2 to be treated in a wastewater treatment step of obtaining treated water 13 and sludges 14 and 15. Is recycled to the biological treatment tank 1 as returned sludge 14, and the other part 15 is introduced into the solubilization step 3 to solubilize and decompose the sludge, and then to the biological treatment tank 1 in the wastewater treatment step. To biodegrade the soluble organic matter and sludge.
The sludge 15 introduced into the solubilization step 3 is introduced into a plurality (two tanks) of

alkali treatment steps

5 and 5 ′ and

oxidation treatment steps

4 and 4 ′, each of which is provided in parallel. Is brought into contact with alkaline water 21 and acidic oxidized water 20 obtained by diaphragm electrolysis of the membrane water to perform solubilization and oxidative decomposition treatment. Then, in the alkali treatment step, an ultrasonic treatment 24 is introduced after 5 'and before mixing with the sludge after the oxidation treatment step.
[0007]
The diaphragm electrolysis of the salt water is performed by using a diaphragm electrolyzer 6 separated by an anode chamber 7 having an anode 9 by a diaphragm 11 and a cathode chamber 8 having a cathode 10, and the salt water is supplied to the anode chamber 7 and the cathode chamber 8 of the apparatus 6. 19 is introduced. In the anode chamber 7, H ⁺ is generated at the anode and becomes acidic, and a chlorine-based oxidizing agent (HClO, Cl ₂ , Cl, etc.) is generated from Cl ^{− in} the salt water to obtain an acidic oxidized water 20 and a cathode. In the chamber 8, OH ⁻ is generated at the cathode to become alkaline, and alkaline water 21 is obtained. The acidic oxidizing water 20 is introduced into the oxidizing tank 4 and the alkaline water 21 is introduced into the alkaline tank 5 for use in the solubilization treatment.
In the alkali treatment step and the oxidation treatment step, treatment tanks are respectively provided in two stages, and a part of the sludge 16 and 17 introduced into each treatment tank is divided into a second alkali tank 5 'and a second oxidation tank 4'. Flow and introduce. Then, after the second alkali treatment 5 ', it is subjected to an ultrasonic treatment. The output of the ultrasonic wave is determined by the amount of the sludge introduced into the alkali treatment step and the contact time with the ultrasonic wave, and a lower frequency is preferable. The mode of the ultrasonic treatment may be a method of storing alkali-treated sludge for a predetermined time in an alkaline tank in which ultrasonic oscillators are arranged at a lower portion, as shown in FIG. 2, or as shown in FIG. Alternatively, a method in which sludge is pump-circulated in an alkaline tank and an ultrasonic oscillator is inserted into the circulation pipe may be used.
[0008]
Next, the operation of these tanks will be described.
First, the first alkaline tank reacts the sludge with the alkali generated by the diaphragm electrolysis, and performs a sludge solubilization treatment by destruction of the sludge cells and elution of the intracellular solution under strong alkaline conditions. Promotes sludge volume reduction using excess alkali from the first alkaline tank. Further, by performing the ultrasonic treatment, the sludge cells that have not been sufficiently destroyed in the first alkaline tank are destroyed, and the volume of the sludge is further reduced.
Next, the first oxidation tank reacts the acid and the oxidizing agent generated by the diaphragm electrolysis with the sludge, and performs oxidative decomposition treatment of the sludge cells under strong acid conditions. The excess acid and oxidizing agent are used to promote oxidative decomposition of sludge.
In FIG. 1, the alkali treatment and the acid oxidation treatment are performed in two lines each in parallel. However, each treatment may be performed in a single tank (only the first alkali tank and the first oxidation tank), It may be performed in a series of two or more tanks.
[0009]
FIG. 4 shows another schematic flow chart of the processing method of the present invention. In FIG. 4, an ultrasonic treatment step 24 is provided after a series of acid / alkali treatments including an acid oxidation treatment step and an alkali treatment step. In FIG. 5, a series of acid-alkali treatment steps including an acid oxidation treatment step and an alkali treatment step are provided after the ultrasonic treatment step 24.
In FIG. 6, the organic sewage 12 is introduced into the adjustment tank 23 and aerated before entering the biological treatment tank 1. The solubilized sludge 18 from the solubilization step 3 is introduced into the biological treatment tank 1 after being subjected to aeration treatment in the pre-aeration tank 22 to volatilize and remove residual chlorine in the electrolytic water used for the solubilization treatment. Instead of the pre-aeration tank 22, the solubilized sludge 18 can be introduced into the adjustment tank 23 and subjected to aeration treatment to remove residual chlorine.
FIG. 7 shows a schematic flow process diagram of circulating a part of the solubilized sludge 18 to the solubilizing step 3. In this way, by circulating a part of the solubilized sludge, the sludge decomposability can be further improved.
[0010]
【Example】
Hereinafter, the present invention will be described specifically with reference to examples.
Example 1
Two sets of an experimental apparatus (RUN1) shown in the processing flow of FIG. 1 and an experimental apparatus (RUN2) in which the solubilization step was removed from the flow were provided, and the quality of treated water and the amount of generated sludge were compared. In RUN1, the amount of sludge introduced into the solubilization step was four times the amount of excess sludge, and 2/3 of the amount was introduced into the alkali treatment step, and 1/3 thereof was introduced into the oxidation treatment step. In the second alkaline tank, １／ of the amount of sludge introduced into the alkali treatment step was introduced, and in the second oxidation tank, １／ of the amount of sludge introduced into the oxidation treatment step was introduced. The residence time in each treatment tank was 4 hours. In this embodiment, a salt solution having a salt concentration of 1/2 of seawater was used as the salt water. The amount of saline used was the same as the amount of excess sludge passed through the electrolytic treatment tank. The ultrasonic treatment after the alkali treatment step was performed at a frequency of 20 kHz and an output of 25 W for one hour.
[0011]
Tables 1 and 2 show the conditions of the diaphragm electrolysis treatment and the properties of the obtained electrolyzed water (alkaline water and acidic oxidized water). In the experiment, the wastewater of Food Company A was used as raw water (pH 6.4, BOD 500 mg / L, COD Mn 240 mg / L, SS 80 mg / L), and the operation conditions of RUN1 and RUN2 were the same except that a solubilization process was provided. did.
[Table 1]

[Table 2]

[0012]
Table 3 shows the properties of the introduced sludge and the treated sludge.
[Table 3]

[0013]
Table 4 shows the experimental results. From Table 4, it was found that RUN1 incorporating the solubilization step including the ultrasonic treatment step produced much less sludge than RUN2, and there was almost no difference in treated water quality.
[Table 4]

[0014]
Example 2
The experimental apparatus (Run 3) shown in the processing flow of FIG. 5 and the experimental apparatus (Run 4) in which the solubilization step was removed from the flow were provided, and the treated water quality and the amount of generated sludge were compared. In RUN3, the amount of sludge introduced into the solubilization step was set to four times the amount of excess sludge. First, ultrasonic waves having a frequency of 20 kHz and an output of 200 W were reacted for 15 minutes. One third of the amount was introduced into the treatment step. In the second alkaline tank, １／ of the amount of sludge introduced into the alkali treatment step was introduced, and in the second oxidation tank, １／ of the amount of sludge introduced into the oxidation treatment step was introduced. The residence time in each treatment tank was 4 hours.
In this embodiment, a salt solution having a salt concentration of 1/2 of seawater was used as the salt water. The amount of saline used was the same as the amount of excess sludge passed through the electrolytic treatment tank.
[0015]
Tables 5 and 6 show the conditions of the diaphragm electrolysis treatment and the properties of the obtained electrolyzed water (alkaline water and acidic oxidized water). In the experiment, the wastewater of the food company A was used as raw water (pH 6.4, BOD 500 mg / L, COD Mn 240 mg / L, SS 80 mg / L), and the operation conditions of RUN3 and RUN4 were the same except that the solubilization step was provided. did.
[Table 5]

[Table 6]

[0016]
Table 7 shows the properties of the introduced sludge and the treated sludge.
[Table 7]

[0017]
Table 8 shows the experimental results. From Table 8, it was found that RUN3 incorporating the solubilization step including the ultrasonic treatment step produced much less sludge than RUN4, and there was almost no difference in treated water quality.
[Table 8]

[0018]
【The invention's effect】
According to the present invention, the treatment using an acidic oxidizing agent and an alkaline agent and ultrasonic treatment can almost completely decompose excess sludge, almost no sludge is generated, and the acidic oxidizing agent and the alkaline agent can be used for the treatment of a diaphragm with salt water. By using the obtained acidic oxidized water and alkaline water, it can be easily obtained at low cost.
[Brief description of the drawings]
FIG. 1 is a flow chart of a sludge volume reduction process using the treatment method of the present invention.
FIG. 2 is a schematic configuration diagram illustrating an example of an ultrasonic processing method.
FIG. 3 is a schematic configuration diagram showing another example of the ultrasonic processing method.
FIG. 4 is another flow chart of the sludge volume reduction process used in another treatment method of the present invention.
FIG. 5 is another flow diagram of the sludge volume reduction process used in another treatment method of the present invention.
FIG. 6 is another schematic flow chart used in the processing method of the present invention.
FIG. 7 is another schematic flow chart for use in the processing method of the present invention.
[Explanation of symbols]
1: aerobic biological treatment tank, 2: sedimentation tank, 3: solubilization step, 4: first oxidation tank, 4 ': second oxidation tank, 5: first alkali tank, 5': second alkali tank, 6 : Diaphragm electrolyzer, 7: anode compartment, 8: cathode compartment, 9: anode, 10: cathode, 11: diaphragm, 12: organic wastewater, 13: treated water, 14: return sludge, 15: excess sludge, 16, 17: part of excess sludge, 18: solubilized sludge, 19: salt water, 20: acidic oxidized water, 21: alkaline water, 22: preaeration tank, 23: conditioning tank, 24: ultrasonic treatment, 25: ultrasonic wave Oscillator

Claims

In a method of treating an organic sewage with an aerobic biological treatment and then solubilizing a part of the obtained sludge and returning the sludge to the aerobic biological treatment step, the solubilizing treatment includes an acidic oxidation using an acidic oxidizing agent. an alkali treatment step using the processing steps and alkaline agents, Ri formed by combining a sonication step, the acid oxidizing agent and an alkali agent, Ru acidic acid water and alkaline water der obtained brine and membrane electrolysis A method for treating organic wastewater, comprising the steps of:

The method for treating organic sewage according to claim 1 , wherein the solubilized sludge is subjected to an aeration process by providing a pre-aeration process before returning to the aerobic biological treatment process.

The method according to claim 1 or 2 , wherein a part of the solubilized sludge is returned to the step of solubilizing and treated again.

A biological treatment tank for aerobic biological treatment of organic wastewater, a solid-liquid separation device for solid-liquid separation of the biologically treated treatment liquid, and a liquefaction treatment means for solubilizing a part of the solid-liquid separated sludge; An organic sewage treatment apparatus having a flow path for returning a treatment solution subjected to a solubilization treatment to the aerobic biological treatment tank, wherein the solubilization treatment means includes an acid oxidation treatment tank using an acid oxidizing agent and an alkali treatment using an alkali agent. A tank, an ultrasonic oscillator for performing an ultrasonic treatment, and an organic sewage comprising a diaphragm electrolyzer for supplying an acidic oxidizing agent and an alkaline agent to the acidic oxidizing treatment tank and the alkaline treating tank. Processing equipment.