JP2003062592A - Method for treating organic waste water containing chloride ion - Google Patents
Method for treating organic waste water containing chloride ionInfo
- Publication number
- JP2003062592A JP2003062592A JP2001256278A JP2001256278A JP2003062592A JP 2003062592 A JP2003062592 A JP 2003062592A JP 2001256278 A JP2001256278 A JP 2001256278A JP 2001256278 A JP2001256278 A JP 2001256278A JP 2003062592 A JP2003062592 A JP 2003062592A
- Authority
- JP
- Japan
- Prior art keywords
- sludge
- waste water
- excess sludge
- chloride ions
- treatment means
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Activated Sludge Processes (AREA)
- Treatment Of Sludge (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、塩化物イオンを含
む有機性汚水の処理方法に関し、特に、し尿や食品工場
排水など塩化物イオンを含む有機性汚水の電解法による
浄化方法に関し、生物学的汚水処理手段からの余剰汚泥
に含まれる塩化物イオンを電気分解により塩素分子へ変
換し、得た塩素分子でもって余剰汚泥の細菌細胞を殺傷
・死滅化し、余剰汚泥の削減が可能となる塩化物イオン
を含む有機性汚水の浄化を行うための新規な改良に関す
る。
【０００２】
【従来の技術】一般に、有機性汚水の浄化処理には、生
物学的処理方法（活性汚泥法、嫌気好気活性汚泥法な
ど）が実用化されている。生物学的処理方法により処理
される原水である有機性汚水中の有機物は、その約５０
％がＣＯ2として排気され、残りの約５０％が微生物の
増殖分となり余剰汚泥が発生している。このような活性
汚泥処理設備などからは余剰汚泥が大量に発生してお
り、その処分には濃縮、脱水し焼却或いは埋立などを行
っているが、焼却による排ガスや廃熱による環境汚染、
埋め立て地の確保などで大きい社会問題となっている。
【０００３】そこで、近年、この余剰汚泥の削減化が必
要に迫られ、その方法について種々提案されている。こ
れら従来の汚泥削減化に関する従来技術の原理（作用・
機構）について、分類すると、図６（余剰汚泥削減化技
術の原理と分類）に示す通りである。余剰汚泥の大部分
を占める細菌類の細胞は、難分解性の高分子物質（ペプ
チドグリカン）から構成される細胞壁と流動性の細胞質
（顆粒状・繊維状の高分子物質を含む）より構成されて
いて、この細胞の外側は粘性物質で覆われている。
【０００４】従来技術を汚泥細胞への作用から分類する
と、細胞殺傷法（以下、Ａ法という。）、細胞質漏出法
（以下、Ｂ法という。）、細胞低分子化法（以下、Ｃ法
という。）となる。また、本発明では汚泥細胞を殺傷・
死滅、細胞質漏出及び低分子化することを総じて基質化
と定義する。Ａ法として塩水を電気分解した処理水と生
物処理槽で発生する余剰汚泥とを混合して汚泥細胞を基
質化し、生物処理槽に返送し、余剰汚泥を削減する特開
平10-76299号公報が開示されている。この特許公報に開
示された発明は隔膜電解槽を用い、塩水を隔膜電解によ
り陽極で発生した酸性酸化水と陰極で発生したアルカリ
水をそれぞれ別々の処理槽（酸化槽、アルカリ槽）で汚
泥と混合し処理するものである。
【０００５】
【発明が解決しようとする課題】従来の処理方法は、以
上のように構成されていたため、次のような課題が存在
していた。すなわち、この隔膜電解槽を用いた処理方法
では、酸化槽とアルカリ槽を各々設ける必要があり装置
設備が複雑になり、また隔膜があるため無隔膜での電解
よりも極間距離を小さくするには限界があり、電解電圧
や消費電力量を低減するためには塩化物イオン濃度を高
くする必要があり、高コストとなっていた。
【０００６】
【課題を解決するための手段】本発明は、以上のような
課題を解決するためになされたもので、特に、生物学的
汚水処理手段からの余剰汚泥に含まれる塩化物イオンを
電気分解により塩素分子へ変換し、この塩素分子で余剰
汚泥の細菌細胞を殺傷・死滅化し、汚泥処理を不必要な
エネルギーの投入をしない低コストでかつ効率的になし
得、余剰汚泥の削減を図ると共に、装置化が簡単で、運
転コストが極めて低く、処理施設の規模、生物処理法の
種類を問わず、余剰汚泥の削減化を可能とした塩化物イ
オンを含む有機性汚水の浄化方法を提供することを目的
とする。本発明による塩化物イオンを含む有機性汚水の
処理方法は、塩化物イオンを含む有機性汚水を生物学的
汚水処理手段により浄化する第１工程と、前記生物学的
汚水処理手段で発生する余剰汚泥の一部或いは全量を前
記生物学的汚水処理手段より引き抜いて電解槽にて電気
分解処理する第２工程と、前記第２工程で電気分解処理
した前記余剰汚泥を前記生物学的汚水処理手段に返送す
る第３工程とよりなる方法である。
【０００７】
【発明の実施の形態】以下、図面と共に本発明による塩
化物イオンを含む有機性汚水の処理方法の好適な実施の
形態について説明する。図１は、本発明による浄化方法
を適用した浄化装置を概略的に示す構成図である。すな
わち、図１において符号１１で示されるものは、し尿や
食品排水など塩化物イオンを含む有機性汚水が原水１０
として提供される曝気槽からなる生物学的汚水処理手段
であり、この曝気槽１１からは処理水１４がオーバーフ
ローするように構成されている。
【０００８】前記曝気槽１１には、その底部１１ａ側か
ら空気源１５によって曝気を行う曝気管１６が設けられ
ており、前記曝気槽１１からの余剰汚泥１７が循環タン
ク３１に供給され、この循環タンク３１と電解槽２１と
の間は循環ポンプ３０により循環され、排気ガス５０が
排気され、撹拌装置４０により撹拌されるように構成さ
れている。
【０００９】前記電解槽２１は、密封型で直流電源２６
に接続された陰極２４と陽極２５を交互に一定間隔で並
べた積層型よりなり、各電極２４、２５間の電極間隙２
１Ａを循環タンク３１内の余剰汚泥１７が一定流速の上
向流となるように構成されている。すなわち、この上向
流の方が汚泥細胞にＨ2が付着して電解槽２１外へ搬送
しやすくなり、陰極２４へのＨ2の付着が阻止できるか
らである。
【００１０】この電解槽２１の前記陽極２５は、チタン
板に二酸化鉛や貴金属酸化物を被覆したもの、あるいは
フェライト板でもよいが、小型化には貴金属被膜チタン
板が好適である。また、陰極２４はステンレス又はチタ
ン板でよい。前記循環タンク３１には、水素ガスを排気
するための排気手段が設けられ、陰極２４で発生した水
素ガスが汚泥に付着して循環タンク３１内で浮上するの
で、循環タンク３１には撹拌装置４０による脱気ができ
るように構成されている。また、この電解槽２１による
電解処理はバッチ式又は連続式の何れも可である。
【００１１】前記電解槽２１において余剰汚泥を電気分
解すると、余剰汚泥中に含まれる塩化物イオンは塩素分
子へ変換され、この塩素分子が汚泥細胞を殺傷し、基質
化すなわち死滅・殺傷するものである。なお、電解槽２
１で死滅・殺傷した基質化余剰汚泥１７ａは循環タンク
３１を経て曝気槽１１内へ返送される。従って、図２及
び図３で示されるように、陽極２５の近傍では塩化物イ
オンは陽極２５へ電子を供与して塩素分子Ｃｌ2へ変換
される。
【００１２】この塩素分子Ｃｌ2（酸性）またはＣｌＯ-
（中性・アルカリ性）は細胞壁を透過して、細胞内の酵
素・遺伝子等の生命活動物質を酸化してＣｌ-になる。
生命活動物質を破壊された細胞は死滅する。このＣｌ-
は再び陽極に移動し電子を供与して塩素へ変換され、上
記反応が繰り返されるリサイクル反応である。電解酸化
で発生した塩素の酸化力は極めて反応活性が高い。すな
わち、陽極２５表面で発生した塩素（Ｃｌ2又はＣｌＯ-
イオン）は高エネルギーを有し化学的に活性で、しかも
電極表面近傍の塩素濃度は図３で示すように陽極の近傍
では極めて高い。この活性塩素の高濃度領域と内部溶液
相との界面で反応が進行するので、電解塩素の細胞殺傷
力は極めて強い。オゾン・塩素ガスの吹き込みや次亜塩
素酸溶液の添加では得られない殺傷力を有する。
【００１３】前記活性塩素は細胞殺傷に必要な量のみを
供給すればよく、余剰汚泥の塩化物イオン濃度を考慮し
て、充分な殺傷率を得られるように電流値と電解時間を
設定する。また、電解処理された汚泥はガスの吸収液と
なるので、極めて過剰の電解処理を行わない限り、陽極
で発生する塩素や副生ガスが外部へ漏洩することはな
い。ただし、陰極より水素ガスが発生するが、この水素
ガスは汚泥と共に循環タンク３１に戻され、ここで排気
ガス５０として大気放出される。
【００１４】また、図４で示される本発明による他の形
態としての活性汚泥法による場合は、図１の循環タンク
３１を必要とせず、余剰汚泥１７の一部を返送汚泥１８
として第１ポンプ１９を介して曝気槽１１に返送してい
る。前記曝気槽１１には、その底部１１ａ側から空気源
１５によって曝気を行う曝気管１６が設けられている。
前記余剰汚泥１７は、第２ポンプ２０を介して電解槽２
１に供給される。この電解槽２１は密封型で直流電源２
６に接続された陰極２４と陽極２５を交互に一定間隔で
並べた積層型よりなり、電極間隙を余剰汚泥１７が一定
流速の上向流となるように構成されている。
【００１５】実施例
本実験例は本発明に基づくものであり、以下に図５の実
験例構成図により説明する。人工的に製造した塩化物イ
オンを含む人工汚水１００を用いて汚水の浄化実験を次
のように行った。この人工汚水は水道水１０Ｌ中に脱脂
粉乳６ｇ、硫酸アンモニウム２．８２ｇ、リン酸２水素
カリウム０．２７ｇ、炭酸水素ナトリウム０．７５ｇ及
び炭酸水素ナトリウム０．３７５ｇを加えてＢＯＤ３０
０ｍｇ／Ｌ、ＣＯＤ３００ｍｇ／Ｌ、ＴＯＣ２６０ｍｇ
／Ｌとなるように調製し、これに食塩を食塩濃度１ w/v
％（塩化物イオン濃度０．６ w/v ％）となるように添
加した。実験例として、人工汚水１００を用いた図５の
活性汚泥装置の曝気槽１１から余剰汚泥１７を抜取り、
電解槽２１にて電解した後、曝気槽１１へ投入した。ま
た、これと比較するために、全く同じ装置及び運転条件
で、余剰汚泥１７の引抜きを行うが電解槽２１を介さな
い比較例１と、余剰汚泥を引抜かず電解槽も介さない比
較例２を行った。
【００１６】（実験方法）曝気槽１１の容積は１０Ｌ、
沈澱槽１２の容積は３Ｌで上記人工汚水を曝気槽１１に
投入した。汚泥滞留時間ＳＲＴ（固形物滞留時間）を２
０日となるように、２日に１回、１Ｌの混合液を曝気槽
１１より抜き取った。Ｗ１６０ｍｍ×Ｈ２７５ｍｍの二
酸化鉛皮膜チタン製陽極と同じサイズのチタン製陰極２
枚を１２ｍｍの間隔で挟んだ電極を有効容積１Ｌの直方
体ＰＶＣ製電解槽２１へ取り付けた。抜取った余剰汚泥
を電解槽２１へ投入し、撹拌しながら電解した。
【００１７】（電解条件）電解処理前の余剰汚泥の酸素
消費量と電解処理後の余剰汚泥の酸素消費量を測定し、
殺傷率を求めることによって電解条件を設定した。汚泥
濃度４，０００ｍｇ／Ｌの余剰汚泥（塩化物イオン濃度
０．６ w/v ％）２Ｌに、１Ａの定電流で電解時間を変
化させ電解を行ったところ、10分間の電解時間で殺傷率
90％以上を得た。この結果から、最適電解条件は、（１
Ａ×１／６ｈ）／（４，０００ｍｇ／Ｌ×２Ｌ）＝０．
０２１Ａｈ／ｇ−ＳＳとなった。例えば、汚泥濃度３，
０００ｍｇ／Ｌの余剰汚泥１Ｌを１Ａの定電流で電解す
る場合には、４分間の電解時間が必要である。
【００１８】（汚泥性状）ＭＬＳＳについては、実験例
では系外への汚泥の抜取りを一切行わなかったのもかか
わらず、３，５００ｍｇ／Ｌで安定していた。一方、汚
泥の抜取りを行う比較例１では３，０００〜３，５００
ｍｇ／Ｌで安定していたが、抜取りを行わない比較例２
では５，０００ｍｇ／Ｌ程度となり汚泥の膨化も生じ不
安定な汚泥性状となった。余剰汚泥を電解し基質化する
ことによって、余剰汚泥の削減化が達成された。ＭＬＶ
ＳＳ／ＭＬＳＳについては、実験例、比較例１および２
ともに、平均０．９以上であった。曝気槽１１内の混合
液を３０分間静置し、ＳＶＩ（汚泥容量指標）を調べ
た。実験例では２００〜２５０であったが、比較例１お
よび２は１００〜２００であった。ただし、比較例２で
は季節の変化に伴う温度の変動の影響を受け、汚泥が膨
化し測定が困難になることもあった。実験例において、
ＳＶＩの値が高いにも関わらず、汚泥フロックと上澄み
液の界面は明確で、沈殿槽１２による固液分離は良好
（沈降汚泥の高さは三角錐分離槽の有効高さの１／３以
内）で、処理水は透明で活性汚泥は目視観察では分離性
能には異常が認められず、極めて安定していた。比較例
１及び２共、季節の変化に伴う温度の変動により、汚泥
の性状が不安定になった。
【００１９】（処理水）実験例と比較例１及び２の処理
水１４の水質に顕著な差異は認められず、処理水中のＢ
ＯＤ、ＣＯＤ、ＴＯＣはそれぞれ５、１０、１０ｍｇ／
Ｌ以下で良好に維持された。
【００２０】（処理コスト）本発明は、従来法に比べて
画期的かつ低コストの余剰汚泥基質化活性汚泥法を提供
するものである。例えば、重力沈降により濃縮した汚泥
（ＭＬＳＳ約１０，０００ｍｇ／Ｌ）を処理したとき
の、処理コストは次のようになる。汚泥濃度４，０００
ｍｇ／Ｌの余剰汚泥（塩化物イオン濃度０．６ w/v
％）１Ｌを１Ａの定電流で、二酸化鉛皮膜チタン板の陽
極により電解電圧３Ｖで電解した場合、殺傷率90％以上
を得るために必要な電解時間は、５分間であるので、汚
泥濃度１０，０００ｍｇ／Ｌの余剰汚泥（塩化物イオン
濃度０．６ w/v ％）１Ｌを電解する場合の電解時間
は、１２．５分となる。したがって、このときの電力
は、１〔Ａ〕×３〔Ｖ〕×１２．５／６０〔ｈ〕／１Ｌ
−濃縮汚泥で、０．６２５ｋＷｈ／ｋＬ−濃縮汚泥とな
り、電気料１２円／ｋＷｈとすると、７．５円／ｋＬ−
濃縮汚泥となる。濃縮余剰汚泥／下水＝０．２〜１％
（平均０．５％）とすると、０．０４円／ｋＬ−下水と
なる。
【００２１】従って、本発明においては、塩化物イオン
を含む有機性汚水を生物処理により浄化する方法であっ
て、第１の工程で生物学的汚水処理により発生する余剰
汚泥の一部或いは全量を電気分解する第２の工程と、こ
の第２の工程で電気分解により発生した塩素分子と汚泥
細胞を接触させ基質化すなわち死滅・殺傷させた後、第
３の工程で該余剰汚泥を生物学的処理工程に返送して同
工程内の微生物群により消化させることにより、余剰汚
泥を削減するものである。また、電解による余剰汚泥基
質化のための消費電力量が低く、汚泥処理に不必要なエ
ネルギーを投入することなく、該汚泥処理を低コストで
かつ効率的に行うことができ、余剰汚泥の削減を図るこ
とができる。さらに、処理時間も短時間であり、沈殿槽
からの処理水１４の水質についても、余剰汚泥の削減化
処理を行わない通常の生物処理法が遵守すべき水質基準
を達成することができる。
【００２２】
【発明の効果】本発明による塩化物イオンを含む有機性
汚水の処理方法は、以上のように構成されているため、
次のような効果を得ることができる。すなわち、生物学
的汚水処理手段からの余剰汚泥中に含まれる塩化物イオ
ンを電解槽で電気分解処理し、塩化物イオンを塩素分子
へ変換して得た塩素分子によって汚泥細菌を殺傷して基
質化すなわち死滅・殺傷化し、汚泥の浄化を行うため、
従来方法に比べると、装置構成が簡略化され、かつ、コ
ストダウンされると共に、処理水質については、従来の
余剰汚泥削減化技術と同等の性能を達成することができ
る。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating organic sewage containing chloride ions, and more particularly to an organic sewage containing chloride ions such as night soil and food factory effluent. In the purification method by the electrolysis method, chloride ions contained in excess sludge from biological wastewater treatment means are converted to chlorine molecules by electrolysis, and the resulting chlorine molecules kill and kill bacterial cells in excess sludge. The present invention also relates to a novel improvement for purifying organic wastewater containing chloride ions, which enables reduction of excess sludge. 2. Description of the Related Art Generally, a biological treatment method (an activated sludge method, an anaerobic aerobic activated sludge method, etc.) has been put to practical use for the purification treatment of organic wastewater. The organic matter in the organic wastewater, which is raw water treated by the biological treatment method, has about 50
% Is exhausted as CO 2 , and the remaining about 50% becomes the growth of microorganisms and generates excess sludge. Excess sludge is generated in large quantities from such activated sludge treatment equipment, etc., and its disposal is concentrated, dewatered, incinerated or landfilled.
It is a major social problem to secure landfills. In recent years, it has become necessary to reduce excess sludge, and various methods have been proposed. Principles of these conventional technologies for reducing sludge
FIG. 6 (Principle and Classification of Surplus Sludge Reduction Technology) is shown in FIG. Bacterial cells, which make up the majority of excess sludge, are composed of cell walls composed of persistent polymer substances (peptidoglycan) and fluid cytoplasm (including granular and fibrous polymeric substances). The outside of these cells is covered with a viscous substance. [0004] When the conventional techniques are classified based on the action on sludge cells, a cell killing method (hereinafter, referred to as A method), a cytoplasm leakage method (hereinafter, referred to as B method), and a cell depolymerization method (hereinafter, referred to as C method). .) In the present invention, sludge cells are killed and
Killing, cytoplasmic leakage and depolymerization are collectively defined as matrixing. Japanese Patent Application Laid-Open No. Hei 10-76299 discloses that as a method A, a mixture of treated water obtained by electrolyzing salt water and excess sludge generated in a biological treatment tank is used to convert sludge cells into a substrate, and returned to the biological treatment tank to reduce excess sludge. It has been disclosed. The invention disclosed in this patent publication uses a diaphragm electrolyzer to separate salt water from acidic oxidized water generated at the anode by diaphragm electrolysis and alkaline water generated at the cathode from sludge in separate treatment tanks (oxidation tank, alkali tank). They are mixed and processed. [0005] Since the conventional processing method is configured as described above, there are the following problems. In other words, in the treatment method using the diaphragm electrolytic cell, it is necessary to provide an oxidation tank and an alkaline tank respectively, which complicates the equipment and equipment. In addition, since there is a diaphragm, the distance between the electrodes is smaller than that in electrolysis without a diaphragm. Has a limit, and it is necessary to increase the chloride ion concentration in order to reduce the electrolytic voltage and the power consumption, which has been expensive. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, is intended to remove chloride ions contained in excess sludge from biological sewage treatment means. It converts it to chlorine molecules by electrolysis, kills and kills the bacterial cells of the excess sludge with the chlorine molecules, and can perform sludge treatment at low cost and efficiently without inputting unnecessary energy, and reduce excess sludge. At the same time, the system is simple to implement, the operating cost is extremely low, and regardless of the size of the treatment facility and the type of biological treatment method, a method for purifying organic wastewater containing chloride ions that enables reduction of excess sludge. The purpose is to provide. The method for treating organic sewage containing chloride ions according to the present invention comprises a first step of purifying organic sewage containing chloride ions by a biological sewage treatment means, and a surplus generated by the biological sewage treatment means. A second step in which part or all of the sludge is withdrawn from the biological sewage treatment means and electrolyzed in an electrolytic cell; and the excess sludge electrolyzed in the second step is subjected to the biological sewage treatment means. And a third step of returning to the third party. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method for treating organic sewage containing chloride ions according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram schematically showing a purification apparatus to which the purification method according to the present invention is applied. That is, what is indicated by reference numeral 11 in FIG. 1 is an organic wastewater containing chloride ions, such as human waste or food wastewater, which is a raw water 10.
This is a biological sewage treatment means comprising an aeration tank provided as a water treatment tank. The aeration tank 11 is configured so that treated water 14 overflows. The aeration tank 11 is provided with an aeration pipe 16 for performing aeration by an air source 15 from the bottom 11a side. Excess sludge 17 from the aeration tank 11 is supplied to a circulation tank 31 and is circulated. The space between the tank 31 and the electrolytic cell 21 is circulated by the circulation pump 30, the exhaust gas 50 is exhausted, and the exhaust gas 50 is stirred by the stirring device 40. The electrolytic cell 21 is of a sealed type and has a DC power supply 26.
, A cathode 24 and an anode 25 connected to each other are alternately arranged at regular intervals.
1A is configured so that the excess sludge 17 in the circulation tank 31 becomes an upward flow at a constant flow rate. That is, the direction of upward flow is easily conveyed adheres H 2 sludge cells into electrolyzer 21 outside is because adhesion of H 2 to the cathode 24 can be prevented. The anode 25 of the electrolytic cell 21 may be a titanium plate coated with lead dioxide or a noble metal oxide, or a ferrite plate, but a noble metal coated titanium plate is suitable for miniaturization. Further, the cathode 24 may be a stainless steel or titanium plate. The circulation tank 31 is provided with an exhaust means for exhausting hydrogen gas, and the hydrogen gas generated at the cathode 24 adheres to the sludge and floats in the circulation tank 31. It is configured so that degassing can be performed. The electrolytic treatment by the electrolytic cell 21 may be either a batch type or a continuous type. When the excess sludge is electrolyzed in the electrolytic cell 21, the chloride ions contained in the excess sludge are converted into chlorine molecules, which kill the sludge cells and turn them into substrates, that is, kill or kill. is there. The electrolytic cell 2
The substrate excess sludge 17a that has died or killed in step 1 is returned to the aeration tank 11 through the circulation tank 31. Therefore, as shown in FIGS. 2 and 3, in the vicinity of the anode 25, chloride ions donate electrons to the anode 25 and are converted into chlorine molecules Cl 2 . [0012] The molecular chlorine Cl 2 (acidic) or ClO -
(Neutral / alkaline) penetrates the cell wall and oxidizes vital substances such as enzymes and genes in the cells to Cl − .
Cells that have lost their vital substances die. The Cl -
Is a recycle reaction in which the electron is transferred to the anode again, is converted into chlorine by donating electrons, and the above reaction is repeated. The oxidizing power of chlorine generated by electrolytic oxidation has extremely high reaction activity. That is, chlorine generated on the surface of the anode 25 (Cl 2 or ClO −
Ions) have high energy and are chemically active, and the chlorine concentration near the electrode surface is extremely high near the anode as shown in FIG. Since the reaction proceeds at the interface between the high concentration region of active chlorine and the internal solution phase, the cell killing power of electrolytic chlorine is extremely strong. It has a killing power that cannot be obtained by blowing ozone / chlorine gas or adding hypochlorous acid solution. It is sufficient to supply only the amount of the active chlorine necessary for killing cells, and the current value and the electrolysis time are set so as to obtain a sufficient killing rate in consideration of the chloride ion concentration of the excess sludge. Further, since the sludge subjected to the electrolytic treatment becomes a gas absorbing liquid, chlorine and by-product gas generated at the anode do not leak to the outside unless extremely excessive electrolytic treatment is performed. However, hydrogen gas is generated from the cathode, and this hydrogen gas is returned to the circulation tank 31 together with the sludge, where it is released to the atmosphere as exhaust gas 50. In the case of the activated sludge method according to another embodiment of the present invention shown in FIG. 4, the circulation tank 31 shown in FIG.
And returned to the aeration tank 11 via the first pump 19. The aeration tank 11 is provided with an aeration tube 16 for performing aeration by an air source 15 from the bottom 11a side.
The excess sludge 17 is supplied to the electrolytic cell 2 via the second pump 20.
1 is supplied. The electrolytic cell 21 is a sealed type and has a DC power source 2.
The cathode 24 and the anode 25 are alternately arranged at regular intervals, and are configured such that the excess sludge 17 flows upward in the electrode gap at a constant flow rate. EXAMPLE The present experimental example is based on the present invention, and will be described below with reference to the experimental example configuration diagram of FIG. A purification experiment of sewage was performed as follows using artificial sewage 100 containing chloride ions produced artificially. This artificial sewage is added to 6 liters of skim milk powder, 2.82 g of ammonium sulfate, 0.27 g of potassium dihydrogen phosphate, 0.75 g of sodium hydrogen carbonate and 0.375 g of sodium hydrogen carbonate in 10 L of tap water, and BOD30 is added.
0 mg / L, COD 300 mg / L, TOC 260 mg
/ L, and the salt is added thereto with a salt concentration of 1 w / v.
% (Chloride ion concentration: 0.6 w / v%). As an experimental example, the excess sludge 17 was extracted from the aeration tank 11 of the activated sludge apparatus of FIG.
After being electrolyzed in the electrolysis tank 21, it was charged into the aeration tank 11. In addition, in order to make a comparison with this, under the same apparatus and operating conditions, the excess sludge 17 was extracted but without passing through the electrolytic cell 21, and the comparative example 2 where the excess sludge was not extracted and the electrolytic cell was not interposed was used. went. (Experimental Method) The volume of the aeration tank 11 is 10 L,
The volume of the sedimentation tank 12 was 3 L, and the artificial wastewater was charged into the aeration tank 11. Sludge retention time SRT (solids retention time) is 2
One liter of the mixed solution was withdrawn from the aeration tank 11 once every two days so that it was day 0. A titanium cathode 2 of the same size as a lead dioxide coated titanium anode of W160 mm x H275 mm
The electrodes with the sheets sandwiched at an interval of 12 mm were attached to a rectangular parallelepiped PVC electrolytic cell 21 having an effective volume of 1 L. The extracted excess sludge was charged into the electrolytic cell 21 and electrolyzed while stirring. (Electrolysis conditions) The oxygen consumption of the excess sludge before the electrolytic treatment and the oxygen consumption of the excess sludge after the electrolytic treatment were measured.
Electrolysis conditions were set by determining the kill rate. The electrolysis was performed by changing the electrolysis time at a constant current of 1 A to 2 L of excess sludge (chloride ion concentration: 0.6 w / v%) having a sludge concentration of 4,000 mg / L.
Got more than 90%. From these results, the optimal electrolysis conditions are (1)
A × 1 / 6h) / (4,000 mg / L × 2 L) = 0.
021 Ah / g-SS. For example, sludge concentration 3,
In the case of electrolyzing 1 L of 000 mg / L excess sludge at a constant current of 1 A, an electrolysis time of 4 minutes is required. (Properties of sludge) Regarding MLSS, it was stable at 3,500 mg / L in spite of the fact that no sludge was extracted out of the system in the experimental examples. On the other hand, in Comparative Example 1 in which sludge is extracted, 3,000 to 3,500
Comparative Example 2 which was stable at mg / L but was not sampled
In this case, the sludge was expanded to about 5,000 mg / L, resulting in unstable sludge properties. The reduction of the excess sludge was achieved by electrolyzing the excess sludge and converting it into a substrate. MLV
For SS / MLSS, experimental examples, comparative examples 1 and 2
In both cases, the average was 0.9 or more. The mixture in the aeration tank 11 was allowed to stand for 30 minutes, and the SVI (sludge volume index) was examined. In the experimental example, the number was 200 to 250, but in Comparative Examples 1 and 2, the number was 100 to 200. However, in Comparative Example 2, the sludge was swollen and the measurement was sometimes difficult due to the influence of the temperature fluctuation accompanying the seasonal change. In the experimental example,
Despite the high SVI value, the interface between the sludge floc and the supernatant is clear, and the solid-liquid separation by the sedimentation tank 12 is good (the height of the settled sludge is within 1/3 of the effective height of the triangular pyramid separation tank) ), The treated water was transparent and the activated sludge was extremely stable without any abnormality in the separation performance by visual observation. In both Comparative Examples 1 and 2, the properties of the sludge became unstable due to temperature fluctuations due to seasonal changes. (Treatment Water) No remarkable difference was observed in the water quality of the treatment water 14 of the experimental example and Comparative Examples 1 and 2,
OD, COD, TOC are 5, 10, 10 mg /
It was well maintained below L. (Treatment Cost) The present invention provides an activated sludge method for converting excess sludge into a substrate, which is revolutionary and lower in cost than the conventional method. For example, when treating sludge (MLSS about 10,000 mg / L) concentrated by gravity sedimentation, the treatment cost is as follows. Sludge concentration 4,000
mg / L of excess sludge (chloride ion concentration 0.6 w / v
%) When 1 L is electrolyzed at a constant current of 1 A with an anode of a lead dioxide coated titanium plate at an electrolysis voltage of 3 V, the electrolysis time required to obtain a kill rate of 90% or more is 5 minutes, and thus the sludge concentration is 10%. The electrolysis time for electrolyzing 1 L of 2,000 mg / L of excess sludge (chloride ion concentration: 0.6 w / v%) is 12.5 minutes. Therefore, the electric power at this time is 1 [A] × 3 [V] × 12.5 / 60 [h] / 1L
-Condensed sludge, 0.625 kWh / kW-Condensed sludge is 7.5 yen / kWL if electricity charges are 12 yen / kWh.
It becomes concentrated sludge. Concentrated excess sludge / sewage = 0.2-1%
(0.5% on average), it is 0.04 yen / kL-sewage. Therefore, in the present invention, a method for purifying organic wastewater containing chloride ions by biological treatment is provided, wherein a part or the entire amount of excess sludge generated by biological wastewater treatment in the first step is removed. A second step of electrolysis, and the chlorine molecules generated by the electrolysis in the second step are brought into contact with sludge cells to form a substrate, that is, kill or kill. Then, in the third step, the excess sludge is subjected to biological treatment. By returning the sludge to the treatment step and digesting it with the microorganisms in the same step, the excess sludge is reduced. In addition, the amount of power consumption for converting the excess sludge into a substrate by electrolysis is low, and the sludge treatment can be performed at low cost and efficiently without inputting unnecessary energy for sludge treatment. Can be achieved. Furthermore, the treatment time is short, and the water quality of the treated water 14 from the sedimentation tank can also achieve the water quality standard that must be observed by a normal biological treatment method that does not perform the excess sludge reduction treatment. The method for treating organic wastewater containing chloride ions according to the present invention is configured as described above.
The following effects can be obtained. That is, chloride ions contained in the excess sludge from the biological sewage treatment means are electrolyzed in an electrolytic cell, and the sludge bacteria are killed by chlorine molecules obtained by converting chloride ions into chlorine molecules. In order to purify sludge,
Compared with the conventional method, the apparatus configuration can be simplified, the cost can be reduced, and the performance of the treated water can be equivalent to that of the conventional technology for reducing excess sludge.
【図面の簡単な説明】
【図１】本発明による塩化物イオンを含む有機性汚水の
処理方法を示す概略構成図である。
【図２】本発明による汚泥細胞殺傷機構を示す説明図で
ある。
【図３】本発明による電極表面近傍の電解塩素反応モデ
ルを示す説明図である。
【図４】本発明による他の形態を示す概略構成図であ
る。
【図５】本発明による実験例を示す構成図である。
【図６】余剰汚泥削減化技術の原理と分類を示す説明図
である。
【符号の説明】
１０ 塩化物イオンを含む有機性汚水（原水）
１１ 生物学的汚水処理手段（曝気槽）
１７ 余剰汚泥
１７ａ 基質化（死滅）余剰汚泥
２１ 電解槽
３１ 循環タンクBRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a method for treating an organic wastewater containing chloride ions according to the present invention. FIG. 2 is an explanatory view showing a sludge cell killing mechanism according to the present invention. FIG. 3 is an explanatory diagram showing an electrolytic chlorine reaction model near the electrode surface according to the present invention. FIG. 4 is a schematic configuration diagram showing another embodiment according to the present invention. FIG. 5 is a configuration diagram showing an experimental example according to the present invention. FIG. 6 is an explanatory diagram showing the principle and classification of the surplus sludge reduction technology. [Description of Signs] 10 Organic wastewater containing chloride ions (raw water) 11 Biological wastewater treatment means (aeration tank) 17 Surplus sludge 17a Substrateization (killing) excess sludge 21 Electrolyte tank 31 Circulation tank
───────────────────────────────────────────────────── フロントページの続き (72)発明者 村上 定瞭 山口県宇部市大字西岐波994−４ (72)発明者 石川 宗孝 京都府八幡市橋本意足20−２ Ｆターム(参考） 4D028 BC03 BC24 BC26 BD06 BD11 BD16 BE08 4D059 AA05 BK12 BK21 CA22 CA28 4D061 DA01 DB10 EA02 EB20 ED12 FA15 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Sadayoshi Murakami 994-4 Nishikinami, Ube City, Yamaguchi Prefecture (72) Inventor Munetaka Ishikawa 20-2 Hashimoto, Hachiman City, Kyoto Prefecture F term (reference) 4D028 BC03 BC24 BC26 BD06 BD11 BD16 BE08 4D059 AA05 BK12 BK21 CA22 CA28 4D061 DA01 DB10 EA02 EB20 ED12 FA15
Claims (1)
物学的汚水処理手段(11)により浄化する第１工程と前記
生物学的汚水処理手段(11)で発生する余剰汚泥(17)の一
部或いは全量を前記生物学的汚水処理手段(11)より引き
抜いて電解槽(21)にて電気分解処理する第２工程と、前
記第２工程で電気分解処理した基質化余剰汚泥(17a) を
前記生物学的汚水処理手段(11)に返送する第３工程と、
よりなることを特徴とする塩化物イオンを含む有機性汚
水の処理方法。Claims: 1. A first step of purifying organic sewage (10) containing chloride ions by a biological sewage treatment means (11) and the biological sewage treatment means (11). A second step in which part or all of the generated excess sludge (17) is withdrawn from the biological sewage treatment means (11) and electrolyzed in an electrolytic cell (21); A third step of returning the surplus sludge (17a) to the biological wastewater treatment means (11);
A method for treating organic sewage containing chloride ions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001256278A JP2003062592A (en) | 2001-08-27 | 2001-08-27 | Method for treating organic waste water containing chloride ion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001256278A JP2003062592A (en) | 2001-08-27 | 2001-08-27 | Method for treating organic waste water containing chloride ion |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003062592A true JP2003062592A (en) | 2003-03-04 |
Family
ID=19084113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001256278A Pending JP2003062592A (en) | 2001-08-27 | 2001-08-27 | Method for treating organic waste water containing chloride ion |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003062592A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005144311A (en) * | 2003-11-14 | 2005-06-09 | Hitachi Kiden Kogyo Ltd | Sludge electrolyzer |
| JP2005169252A (en) * | 2003-12-11 | 2005-06-30 | Hitachi Maxell Ltd | Surplus sludge reduction method |
| JP2005169253A (en) * | 2003-12-11 | 2005-06-30 | Hitachi Maxell Ltd | Method for decreasing excess sludge |
| JP2006239545A (en) * | 2005-03-02 | 2006-09-14 | Hitachi Plant Technologies Ltd | Method for sludge treatment |
| JP2006326373A (en) * | 2005-05-23 | 2006-12-07 | Suido Kiko Kaisha Ltd | Operation method of surplus sludge treatment apparatus, and surplus sludge treatment apparatus |
| JP2007203232A (en) * | 2006-02-03 | 2007-08-16 | Hitachi Plant Technologies Ltd | Electrolysis device for sludge |
| JP2008049343A (en) * | 2007-11-09 | 2008-03-06 | Nishihara Environment Technology Inc | Organic waste water treatment device |
| CN116924596A (en) * | 2023-05-30 | 2023-10-24 | 深圳市新西林园林景观有限公司 | Electrochemical device for sponge urban sewage treatment and treatment method thereof |
-
2001
- 2001-08-27 JP JP2001256278A patent/JP2003062592A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005144311A (en) * | 2003-11-14 | 2005-06-09 | Hitachi Kiden Kogyo Ltd | Sludge electrolyzer |
| JP4511820B2 (en) * | 2003-11-14 | 2010-07-28 | 株式会社日立プラントテクノロジー | Sludge electrolyzer |
| JP2005169252A (en) * | 2003-12-11 | 2005-06-30 | Hitachi Maxell Ltd | Surplus sludge reduction method |
| JP2005169253A (en) * | 2003-12-11 | 2005-06-30 | Hitachi Maxell Ltd | Method for decreasing excess sludge |
| JP4712297B2 (en) * | 2003-12-11 | 2011-06-29 | 株式会社日立プラントテクノロジー | Method for reducing excess sludge |
| JP2006239545A (en) * | 2005-03-02 | 2006-09-14 | Hitachi Plant Technologies Ltd | Method for sludge treatment |
| JP4510699B2 (en) * | 2005-05-23 | 2010-07-28 | 水道機工株式会社 | Surplus sludge treatment equipment |
| JP2006326373A (en) * | 2005-05-23 | 2006-12-07 | Suido Kiko Kaisha Ltd | Operation method of surplus sludge treatment apparatus, and surplus sludge treatment apparatus |
| JP4689483B2 (en) * | 2006-02-03 | 2011-05-25 | 株式会社日立プラントテクノロジー | Sludge electrolytic treatment equipment |
| JP2007203232A (en) * | 2006-02-03 | 2007-08-16 | Hitachi Plant Technologies Ltd | Electrolysis device for sludge |
| JP2008049343A (en) * | 2007-11-09 | 2008-03-06 | Nishihara Environment Technology Inc | Organic waste water treatment device |
| CN116924596A (en) * | 2023-05-30 | 2023-10-24 | 深圳市新西林园林景观有限公司 | Electrochemical device for sponge urban sewage treatment and treatment method thereof |
| CN116924596B (en) * | 2023-05-30 | 2024-06-07 | 深圳市新西林园林景观有限公司 | Electrochemical device for sponge urban sewage treatment and treatment method thereof |
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