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JPH1085752A - Wastewater treatment method - Google Patents

Wastewater treatment method

Info

Publication number
JPH1085752A
JPH1085752A JP8243598A JP24359896A JPH1085752A JP H1085752 A JPH1085752 A JP H1085752A JP 8243598 A JP8243598 A JP 8243598A JP 24359896 A JP24359896 A JP 24359896A JP H1085752 A JPH1085752 A JP H1085752A
Authority
JP
Japan
Prior art keywords
reaction tank
wastewater
cathode
nitrogen
anode
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
Application number
JP8243598A
Other languages
Japanese (ja)
Inventor
Toshiaki Tsubone
俊明 局
Tatsuo Takechi
辰夫 武智
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Engineering Corp
Original Assignee
NKK Corp
Nippon Kokan Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NKK Corp, Nippon Kokan Ltd filed Critical NKK Corp
Priority to JP8243598A priority Critical patent/JPH1085752A/en
Publication of JPH1085752A publication Critical patent/JPH1085752A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/46115—Electrolytic cell with membranes or diaphragms
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage

Landscapes

  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

PROBLEM TO BE SOLVED: To enable the removal of nitrogen components in wastewater with space and energy saved. SOLUTION: Received water is introduced into a biological reaction tank 11. By the treatment in the first stage 11a of the reactor 11, most of carbonaceous pollutants are removed, and part of a mixture of primary treatment water in a stage in which ammonia is not yet oxidized practically and activated sludge is introduced into the anode chamber 19 of an electrode reaction tank 19 through an anode side inflow channel 21. Besides, in the latter stage 11b of the biological reaction tank 11, the oxidation of ammoniacal nitrogen by microorganisms takes place mainly. Secondary treatment water treated in the first stage 11a or the latter stage 11b is introduced into the cathode chamber 20 of the electrode reaction tank 12 through a cathode side inflow channel 22. In the reaction tank 12, direct current voltage is applied between the anode 13 and the cathode 14 through wirings 15, 16 to electrolyze the primary and secondary treatment water.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、廃水処理方法に関
する。The present invention relates to a method for treating wastewater.

【０００２】[0002]

【従来の技術】従来、汚水中から窒素成分を除去する方
法としては、生物学的方法や物理化学的方法が用いられ
ている。これらのうち生物学的方法は、アンモニア態窒
素を酸化する能力を有する微生物の作用を利用して、廃
水中のアンモニア態窒素を、亜硝酸態窒素または硝酸態
窒素（以下、ＮＯｘ−Ｎと記す）まで酸化した後、ＮＯ
ｘ−Ｎを還元する能力を有する微生物の作用を利用し
て、廃水中のＮＯｘ−Ｎを窒素ガスに還元して、大気中
に放散させる方法（以下、方法Ｉという）である。2. Description of the Related Art Conventionally, biological methods and physicochemical methods have been used to remove nitrogen components from wastewater. Among these, biological methods utilize the action of microorganisms having the ability to oxidize ammonia nitrogen to convert ammonia nitrogen in wastewater into nitrite nitrogen or nitrate nitrogen (hereinafter referred to as NOx-N). After oxidation to NO)
This is a method of reducing NOx-N in wastewater to nitrogen gas by utilizing the action of microorganisms having the ability to reduce xN and dispersing it into the atmosphere (hereinafter referred to as method I).

【０００３】かかる生物学的方法では、ＮＯｘ−Ｎを窒
素ガスに還元するに当たって還元剤が必要である。例え
ば、水の電気分解によって陰極で発生する水素ガスを還
元剤として利用する方法（以下、方法IIという）の研究
（水環境学会誌、vol.17,No.10,pp.623-631 ）が行われ
ている。また、ＮＯｘ−Ｎを電解還元して窒素ガスに処
理する方法（以下、方法III という）（特開平２−１７
２５９０号公報）も知られている。[0003] In such a biological method, a reducing agent is required to reduce NOx-N to nitrogen gas. For example, research on the method of using hydrogen gas generated at the cathode by water electrolysis as a reducing agent (hereinafter referred to as method II) (Journal of Japan Society on Water Environment, vol. 17, No. 10, pp. 623-631) Is being done. In addition, a method of electrolytically reducing NOx-N and processing it into nitrogen gas (hereinafter, referred to as method III) (Japanese Patent Laid-Open No. 2-17)
No. 2590) is also known.

【０００４】また、物理化学的な処理方法としては、Ｔ
ｉ／Ｐｔ等の材料を用いた電極を陽極として用い、廃水
を電気的に処理することによって廃水中のアンモニア態
窒素を窒素ガスに直接酸化する方法（以下、方法IVとい
う）の研究が行われている（Water Research,vol.29,N
o.2,pp.517-524,(1995)）。また、水の電気分解により
発生する次亜塩素酸を利用して、アンモニアを処理する
方法（以下、方法Ｖという）（中村文雄ら訳、”廃水の
高度浄化法”、p.224,pp.205-206(1975)）も公知であ
る。[0004] As a physicochemical treatment method, T
Research has been conducted on a method of directly oxidizing ammonia nitrogen in wastewater to nitrogen gas by electrically treating the wastewater using an electrode made of a material such as i / Pt as an anode (hereinafter referred to as method IV). (Water Research, vol. 29, N
o.2, pp.517-524, (1995)). Also, a method of treating ammonia using hypochlorous acid generated by electrolysis of water (hereinafter referred to as method V) (translated by Fumio Nakamura et al., “Advanced Purification Method of Wastewater”, p.224, pp. 205-206 (1975)).

【０００５】[0005]

【発明が解決しようとする課題】上述の生物学的な処理
方法は、生物反応を利用しているために、反応速度が小
さく、反応に長時間を要し、反応時間を短縮するために
は反応槽容積を大きくする必要がある。以下、この問題
をより具体的に説明する。図１０は、従来の標準活性汚
泥法と呼ばれる生物学的廃水処理のフローを示す。この
方法では、流入水１６１は、活性汚泥が収容された好気
処理のための反応槽１６２に流入され、次いで、活性汚
泥を含む処理水１６３を沈殿池１６４に導入する。沈殿
池１６４で活性汚泥を沈殿させて処理水１６３から分離
する。回収された活性汚泥１６５は反応槽１６２に戻さ
れ、一方、処理水１６６は放流される。この方法は、現
在の廃水処理の主流であるが、主に炭素質の汚濁物質の
除去を目的として設計されたもので、現在の施設では、
アンモニア態窒素の除去には反応時間が不足しており、
アンモニア態窒素の酸化率が小さいという問題がある。
すなわち、廃水の生物学的な処理では、まず、炭素質の
汚濁物質の分解が起こった後、アンモニア態窒素の酸化
が行われる。しかし、現状の設備は炭素質の汚濁物質の
分解を目的として設計されている。このため、現存の施
設において、アンモニア態窒素の酸化を向上させるため
には、反応槽１６２を拡張する必要があり、また、新規
設備の設計では大型の反応槽１６２を採用する必要があ
る。いずれの場合にも、設備コストの増大を避けること
ができない。また、標準活性汚泥法は、反応槽１６２全
体が好気条件であるため、無酸素の部分が存在せず、Ｎ
Ｏｘ−Ｎを窒素ガスに還元することができず、処理水１
６６中にＮＯｘ−Ｎが残留する不都合がある。The above-mentioned biological treatment method uses a biological reaction, so that the reaction speed is low, the reaction takes a long time, and the reaction time is shortened. It is necessary to increase the reactor volume. Hereinafter, this problem will be described more specifically. FIG. 10 shows a flow of a conventional biological wastewater treatment called a standard activated sludge method. In this method, the inflow water 161 flows into the reaction tank 162 for aerobic treatment in which the activated sludge is stored, and then the treated water 163 containing the activated sludge is introduced into the sedimentation tank 164. The activated sludge is settled in the settling tank 164 and separated from the treated water 163. The recovered activated sludge 165 is returned to the reaction tank 162, while the treated water 166 is discharged. This method, which is currently the mainstream of wastewater treatment, was designed primarily for the purpose of removing carbonaceous pollutants.
The reaction time is insufficient to remove ammonia nitrogen,
There is a problem that the oxidation rate of ammonia nitrogen is small.
That is, in biological treatment of wastewater, first, decomposition of carbonaceous pollutants occurs, and then oxidation of ammonia nitrogen is performed. However, current facilities are designed to decompose carbonaceous pollutants. For this reason, in existing facilities, in order to improve the oxidation of ammonia nitrogen, it is necessary to expand the reaction tank 162, and it is necessary to employ a large-sized reaction tank 162 in designing a new facility. In either case, an increase in equipment cost cannot be avoided. In the standard activated sludge method, since the entire reaction tank 162 is under aerobic conditions, there is no oxygen-free part,
Ox-N cannot be reduced to nitrogen gas and treated water 1
66, there is a problem that NOx-N remains.

【０００６】図１１は、従来の硝化−内生脱窒法と呼ば
れる生物学的処理のフローである。この方法では、流入
水１７１は、反応槽１７２の活性汚泥が収容された好気
処理のため好気部１７３に流入され、次いで嫌気処理の
ための嫌気部１７４に導入される。この後、活性汚泥を
含む処理水１７５は沈殿池１７６に導入される。沈殿池
１７６で活性汚泥を沈殿させて処理水１７５から分離す
る。回収された活性汚泥１７７は好気部１７３に戻さ
れ、一方、処理水１７８は放流される。この方法では、
反応槽１７２の前段の好気部１７３を好気条件としてア
ンモニア態窒素をＮＯｘ−Ｎまで酸化した後に、後段の
嫌気部１７４を無酸素条件とすることにより、ＮＯｘ−
Ｎを窒素ガスに還元するものである。しかし、生物の反
応速度が小さいために、巨大な反応槽１７２（滞留時間
として２０〜２４時間程度）を必要とする。FIG. 11 shows a flow of a biological treatment called a conventional nitrification-endogenous denitrification method. In this method, the inflow water 171 flows into the aerobic section 173 for aerobic treatment in which the activated sludge of the reaction tank 172 is stored, and is then introduced into the anaerobic section 174 for anaerobic treatment. Thereafter, the treated water 175 containing the activated sludge is introduced into the sedimentation tank 176. The activated sludge is settled in the settling tank 176 and separated from the treated water 175. The recovered activated sludge 177 is returned to the aerobic section 173, while the treated water 178 is discharged. in this way,
After oxidizing ammonia nitrogen to NOx-N under the aerobic part 173 at the former stage of the reaction tank 172 under aerobic conditions, the anaerobic part 174 at the subsequent stage is made into anoxic condition, so that NOx-
N is reduced to nitrogen gas. However, since the reaction speed of the organism is low, a huge reaction tank 172 (residence time of about 20 to 24 hours) is required.

【０００７】図１２は、硝化液循環法とよばれる生物学
的処理のフローである。この方法では、流入水１８１
は、反応槽１８２の嫌気部１８３に流入され、次いで好
気部１８４に導入される。処理水と活性汚泥の混合液１
８９は嫌気部１８３に戻される。この後、活性汚泥を含
む処理水１８５は沈殿池１８６に導入される。沈殿池１
８６で活性汚泥を沈殿させて処理水１８５から分離す
る。回収された活性汚泥１８７は好気部１８３に戻さ
れ、一方、処理水１８８は放流される。この方法では、
反応槽１８２の後段の好気部１８４を好気条件としてア
ンモニア態窒素をＮＯｘ−Ｎまで酸化した後に、処理水
と活性汚泥の混合液１８９を前段の嫌気部１８３に循環
し、嫌気部１８３で無酸素条件下で、ＮＯｘ−Ｎを窒素
ガスに還元する。しかし、巨大な反応槽１８２（滞留時
間として１６〜２０時間程度）を必要とする。FIG. 12 shows a flow of a biological treatment called a nitrification liquid circulation method. In this method, the influent 181
Is introduced into the anaerobic section 183 of the reaction tank 182 and then introduced into the aerobic section 184. Mixture 1 of treated water and activated sludge
89 is returned to the anaerobic section 183. Thereafter, the treated water 185 containing the activated sludge is introduced into the sedimentation tank 186. Settling basin 1
At 86, the activated sludge is settled and separated from the treated water 185. The recovered activated sludge 187 is returned to the aerobic section 183, while the treated water 188 is discharged. in this way,
After oxidizing ammonia nitrogen to NOx-N under the aerobic part 184 at the latter stage of the reaction tank 182 under aerobic conditions, a mixed solution 189 of treated water and activated sludge is circulated to the anaerobic part 183 at the former stage. Under anoxic conditions, NOx-N is reduced to nitrogen gas. However, it requires a huge reaction tank 182 (a residence time of about 16 to 20 hours).

【０００８】また、この方法では、好気部１８４で生成
したＮＯｘ−Ｎの一部は、嫌気部１８３に循環されずに
処理水１８５となるため、理論上、高い窒素除去率を得
るためには、循環比を高める必要がある。しかしなが
ら、循環比を高めることは循環ポンプの消費エネルギー
の増大につながる。また、残りの流入水１８５は嫌気部
１８３に循環されずに系外へ排出されるため、処理水１
８８中にＮＯｘ−Ｎが残留し、１００％の窒素除去率は
得られない。また、生物学的処理方法の共通の問題点と
して、生物反応の速度を制御することは難しく、流入水
の水量や水質の変動に対して弱いという点が挙げられ
る。Further, in this method, a part of the NOx-N generated in the aerobic section 184 is not circulated to the anaerobic section 183 but becomes the treated water 185. Therefore, in theory, it is necessary to obtain a high nitrogen removal rate. Needs to increase the circulation ratio. However, increasing the circulation ratio leads to an increase in the energy consumption of the circulation pump. Further, since the remaining inflow water 185 is discharged to the outside of the system without being circulated to the anaerobic section 183, the treated water 1
NOx-N remains in 88, and a nitrogen removal rate of 100% cannot be obtained. In addition, a common problem of biological treatment methods is that it is difficult to control the speed of a biological reaction, and it is vulnerable to fluctuations in the amount and quality of inflow water.

【０００９】また、方法IIでは、陰極での水素の生成反
応は下式（１）で、発生した水素とＮＯｘ−Ｎの反応は
下式（２）で表される。 Ｈ2 Ｏ＋ｅ- → 1/2 Ｈ2 ＋ＯＨ- （１） 式（１）および（２）から１モルのＮＯｘ−Ｎを窒素ガ
スに還元するためには、１０ファラデーの電気量が必要
であることが判る。従って、電圧を３Ｖと仮定すると、
ＮＯｘ−Ｎ濃度が２５ｍｇ／リットルの廃水１ｍ3 を処
理するのに必要な電力量は、０．７２ＫＷＨと計算され
る。この値は、生物学的な窒素除去方法における処理プ
ロセス全体（ポンプ類、ブロワー等）での消費電力が
０．５ＫＷＨ程度であることを考えると非常に大きな値
であり、よって方法Ｉは、エネルギー消費の面から問題
がある。In the method II, the reaction of producing hydrogen at the cathode is represented by the following formula (1), and the reaction between the generated hydrogen and NOx-N is represented by the following formula (2). H 2 O + e − → 1/2 H 2 + OH − (1) From the formulas (1) and (2), it is necessary that 10 Faraday of electricity be required to reduce 1 mol of NOx—N to nitrogen gas. I understand. Therefore, assuming a voltage of 3V,
Amount of power needed to NOx-N concentration is treated wastewater 1 m 3 of 25 mg / l is calculated as 0.72KWH. This value is very large considering that the power consumption of the entire treatment process (pumps, blowers, etc.) in the biological nitrogen removal method is about 0.5 KWH. There is a problem in terms of consumption.

【００１０】さらに、方法IIでは、陽極に炭素材が用い
られている。このため、陽極では、発生する酸素によっ
て炭素材が二酸化炭素に変わる反応が起こっているだけ
で、陽極は、廃水の処理には利用されていない。方法II
I についても、方法IIと同様の問題が認められる。Further, in the method II, a carbon material is used for the anode. For this reason, at the anode, only the reaction of converting the carbon material into carbon dioxide occurs due to the generated oxygen, and the anode is not used for treating wastewater. Method II
For I, the same problems as in Method II are observed.

【００１１】また、方法IVでは、陽極での反応は下式
（３）に従うとされている。 2ＮＨ3 ＋ 6ＯＨ- →Ｎ2 ＋ 6Ｈ2 Ｏ＋ 6ｅ- （３） この式（３）から、１モルのアンモニア態窒素を窒素ガ
スに酸化するためには、３ファラデーの電気量が必要で
あることが判る。従って、電圧を３Ｖと仮定すると、ア
ンモニア態窒素濃度が２５ｍｇ／ｌの廃水１ｍ3 を処理
するのに必要な電力量は０．２２ＫＷＨと計算される。
一方、従来の窒素除去型ではない生物処理プロセスの消
費エネルギーは０．２〜０．４ＫＷＨ／ｍ3 とされてい
る。故に、この生物処理プロセスの消費エネルギーに上
述の電気量を加算すると、方法IVにおける総消費エネル
ギーは、０．４２〜０．６２ＫＷＨ／ｍ3 となる。この
値は、生物学的な窒素除去方法における処理プロセス全
体（ポンプ類、ブロワー等）での消費電力である０．５
ＫＷＨ程度と比べて大差無い値ではあるが、現段階で
は、電流効率は２０％程度以下と小さい値しか得られ
ず、やはりエネルギー消費の面から問題がある。さら
に、廃水中に、アンモニア態窒素以外の還元生物質が存
在すると、その酸化のために電力が消費されるため、ア
ンモニア態窒素の処理の見かけの電流効率はさらに小さ
い値となる。また、陰極から水素が発生するが、この水
素を積極的に処理に利用しようとした例はない。なお、
従来技術Ｖにおいても、消費エネルギーは大きく、陰極
から発生する水素を積極的に処理に利用しようとした例
はない。また、陽極でアンモニア態窒素をＮＯｘ−Ｎに
酸化した後、陽極処理水を陰極側に導入し、陰極でＮＯ
ｘ−Ｎを窒素ガスに処理する方法（以下、方法VIとい
う）（特開平第６−１８２３４４号公報）も公知であ
る。しかし、この方法では、窒素ガスよりさらに酸化さ
れた形態のＮＯｘ−Ｎまでいったん酸化し、そのＮＯｘ
−Ｎを、還元処理することとなるため、消費エネルギー
は従来技術IVと比較して、さらに大きなものとなる。In the method IV, the reaction at the anode follows the following formula (3). 2NH 3 + 6OH − → N 2 + 6H 2 O + 6e − (3) From this formula (3), it is necessary to oxidize 1 mol of ammonia nitrogen to nitrogen gas, and that 3 Faraday electricity is required. I understand. Therefore, assuming a voltage of 3 V, the electric energy required to treat 1 m 3 of wastewater having an ammonia nitrogen concentration of 25 mg / l is calculated to be 0.22 KWH.
On the other hand, the energy consumption of a conventional biological treatment process that is not a nitrogen removal type is 0.2 to 0.4 KWH / m 3 . Therefore, when the above-mentioned amount of electricity is added to the consumed energy of this biological treatment process, the total consumed energy in the method IV is 0.42 to 0.62 KWH / m 3 . This value is 0.5% which is the power consumption of the entire treatment process (pumps, blowers, etc.) in the biological nitrogen removal method.
Although the value is not much different from the value of about KWH, at this stage, the current efficiency is only about 20% or less, which is still a problem in terms of energy consumption. Furthermore, if a reducing biomass other than ammonia nitrogen is present in the wastewater, power is consumed for its oxidation, so that the apparent current efficiency of the ammonia nitrogen treatment becomes even smaller. In addition, although hydrogen is generated from the cathode, there is no example in which this hydrogen is actively used for processing. In addition,
Even in the prior art V, the energy consumption is large, and there is no example in which hydrogen generated from the cathode is actively used for the treatment. After oxidizing ammonia nitrogen to NOx-N at the anode, anodized water was introduced to the cathode side, and NO
A method of treating xN into nitrogen gas (hereinafter referred to as method VI) (Japanese Patent Application Laid-Open No. 6-182344) is also known. However, according to this method, NOx-N is oxidized once more than nitrogen gas, and the NOx-N
Since -N is subjected to a reduction treatment, the energy consumption is further increased as compared with the prior art IV.

【００１２】本発明は、かかる点に鑑みてなされたもの
であり、反応槽の容積が小さく、かつ、処理水の水質の
変動が小さくかつ消費エネルギーの小さい廃水中の窒素
成分の除去を可能とする廃水処理方法を提供する。The present invention has been made in view of the above point, and it is possible to remove a nitrogen component in wastewater having a small capacity of a reaction tank, a small fluctuation in the quality of treated water, and a small energy consumption. Wastewater treatment method.

【００１３】[0013]

【課題を解決するための手段】本発明は、廃水を生物反
応槽に導入して前記廃水に生物処理を施す工程と、電極
反応槽内に陽極としてのアンモニア態窒素を窒素ガスに
酸化する能力を有する電極または塩素イオンを塩素ガス
に酸化する能力を有する電極と陰極として水を水素ガス
に還元する能力を有する電極または硝酸態窒素および／
または亜硝酸態窒素を窒素ガスに還元する能力を有する
電極をそれぞれ配置し、前記生物反応槽で生物処理を受
けた前記廃水を前記電極反応槽に導入し、前記陽極およ
び前記陰極の間に電圧を印加して前記廃水の電気分解を
行い、前記陽極において前記廃水中のアンモニア態窒素
を窒素ガスに酸化すると共に、前記陰極において前記廃
水中の硝酸態窒素および／または亜硝酸態窒素を窒素ガ
スに還元する工程とを具備することを特徴とする廃水処
理方法を提供する。SUMMARY OF THE INVENTION The present invention provides a process for introducing wastewater into a biological reactor and subjecting the wastewater to biological treatment, and a process for oxidizing ammonia nitrogen as an anode into nitrogen gas in an electrode reactor. Or an electrode capable of oxidizing chlorine ions to chlorine gas and an electrode capable of reducing water to hydrogen gas as a cathode or nitrate nitrogen and / or
Alternatively, electrodes each having an ability to reduce nitrite nitrogen to nitrogen gas are arranged, the wastewater subjected to biological treatment in the biological reaction tank is introduced into the electrode reaction tank, and a voltage is applied between the anode and the cathode. To electrolyze the wastewater, oxidize the ammonia nitrogen in the wastewater to nitrogen gas at the anode, and convert the nitrate nitrogen and / or nitrite nitrogen in the wastewater into nitrogen gas at the cathode. And a step of reducing wastewater to a wastewater treatment method.

【００１４】[0014]

【発明の実施の形態】以下、本発明の廃水処理方法の実
施形態を図面を参照して説明する。図１は、本発明の第
１実施形態に係る廃水処理方法に用いられる廃水処理設
備を示す概略図である。図中１１は生物反応槽である。
生物反応槽１１は、標準活性汚泥法の反応槽である。生
物反応槽１１の底部には散気手段が配置され、散気手段
から酸素含有ガス（例えば、空気）が吹き込まれ、生物
反応槽１１の内部全体が好気条件になっている。生物反
応槽１１内には、炭素質の汚濁物質生物の分解能力を有
する微生物やアンモニアの酸化能力を有する微生物が浮
遊している。生物反応槽１１には、処理前の廃水（以
下、流入水という）１が供給されるようになっている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the wastewater treatment method of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a wastewater treatment facility used in the wastewater treatment method according to the first embodiment of the present invention. In the figure, reference numeral 11 denotes a biological reaction tank.
The biological reaction tank 11 is a reaction tank of a standard activated sludge method. A diffuser is arranged at the bottom of the biological reaction tank 11, and an oxygen-containing gas (for example, air) is blown from the diffuser, so that the entire inside of the biological reaction tank 11 is in an aerobic condition. In the biological reaction tank 11, microorganisms capable of decomposing carbonaceous pollutant organisms and microorganisms capable of oxidizing ammonia are suspended. The biological reaction tank 11 is supplied with wastewater (hereinafter referred to as inflow water) 1 before treatment.

【００１５】一方、図１中１２は、電極反応槽である。
電極反応槽１２の内部には、一対の陽極１３および陰極
１４が互いに対向して配置されている。陽極１３は、ア
ンモニア態窒素を窒素ガスに酸化する能力を有する電極
で構成されている。アンモニア態窒素を窒素ガスに酸化
する能力を有する電極は、例えば、表面を白金で被覆さ
れたチタン電極（Ｔｉ／Ｐｔ電極）、表面を白金とイリ
ジウムで被覆されたチタン電極（Ｔｉ／Ｐｔ／Ｉｒ）等
である。On the other hand, reference numeral 12 in FIG. 1 denotes an electrode reaction tank.
Inside the electrode reaction tank 12, a pair of anodes 13 and cathodes 14 are arranged to face each other. The anode 13 is constituted by an electrode having an ability to oxidize ammonia nitrogen to nitrogen gas. Examples of the electrode capable of oxidizing ammonia nitrogen to nitrogen gas include a titanium electrode whose surface is coated with platinum (Ti / Pt electrode) and a titanium electrode whose surface is coated with platinum and iridium (Ti / Pt / Ir). ).

【００１６】一方、陰極１４は、水を水素ガスに還元す
る能力を有する電極で構成される。この第１実施形態で
は、陰極１４は、表面に微生物が固定化された炭素電極
である。On the other hand, the cathode 14 is composed of an electrode capable of reducing water to hydrogen gas. In the first embodiment, the cathode 14 is a carbon electrode having microorganisms immobilized on the surface.

【００１７】上記陽極１３および陰極１４は、それぞれ
配線１５、１６を介して電源１７の陽極側および陰極側
にそれぞれ接続されている。電極反応槽１２内は、導電
性隔膜１８により、陽極室１９および陰極室２０に分割
されている。この導電性隔膜１８は、電気を通すが水分
子、固形物、アンモニア態窒素およびＮＯｘ−Ｎを実質
的に透過しない材質からなる。導電性隔膜１８は、多く
のメーカーから供給されているが、 ａ）異符号イオン間の選択透過性が高いこと、 ｂ）良好な電気伝導性を有すること、 ｃ）水の輸率が低いこと等の条件を満たすことが望まし
い。The anode 13 and the cathode 14 are connected to the anode side and the cathode side of a power supply 17 via wirings 15 and 16, respectively. The inside of the electrode reaction tank 12 is divided by a conductive diaphragm 18 into an anode chamber 19 and a cathode chamber 20. The conductive diaphragm 18 is made of a material that conducts electricity but does not substantially transmit water molecules, solids, ammonia nitrogen and NOx-N. The conductive diaphragm 18 is supplied by a number of manufacturers, a) high permselectivity between ions of different signs, b) good electrical conductivity, c) low water transport number. It is desirable to satisfy such conditions.

【００１８】電極反応槽１２の陽極室１９には、陽極側
流入管路２１が接続されている。この陽極側流入管路２
１の他端部は、生物反応槽１１の前段部１１ａに接続さ
れている。この陽極側流入管路２１により、生物反応槽
１１の前段部１１ａから、ここで処理を受けた廃水（以
下、１次処理水という）および活性汚泥の混合液の一部
が陽極室１９に導入される。The anode chamber 19 of the electrode reaction tank 12 is connected to an anode-side inflow pipe 21. This anode side inflow line 2
The other end of 1 is connected to the front stage 11 a of the biological reaction tank 11. Through the anode-side inflow pipe 21, a part of the mixed liquid of the wastewater treated here (hereinafter referred to as primary treated water) and the activated sludge is introduced into the anode chamber 19 from the front stage 11 a of the biological reaction tank 11. Is done.

【００１９】一方、電極反応槽１２の陰極室２０には、
陰極側流入管路２２が接続されている。この陰極側流入
管路２２の他端部は、生物反応槽１１の後段部１１ｂに
接続されている。この陰極側流入管路２２により、生物
反応槽１１の後段部１１ｂから、前段部１１ａおよび後
段部１１ｂで処理をうけた廃水（以下、２次処理水とい
う）および活性汚泥の混合物が陰極室２２に導入され
る。On the other hand, in the cathode chamber 20 of the electrode reaction tank 12,
The cathode-side inflow conduit 22 is connected. The other end of the cathode-side inflow conduit 22 is connected to a rear part 11 b of the biological reaction tank 11. The cathode-side inflow conduit 22 allows a mixture of wastewater (hereinafter referred to as secondary treated water) and activated sludge that have been treated in the front stage 11 a and the rear stage 11 b to flow from the rear stage 11 b of the biological reaction tank 11 to the cathode chamber 22. Will be introduced.

【００２０】電極反応槽１２の陽極室１９および陰極室
２０の後段部には、それぞれ、流出管路２３、２４がそ
れぞれ接続されている。これらの流出管路２３、２４は
一つの流出管路２５に合流している。この流出管路２５
の後流側端部は、沈殿池２６まで達している。この沈殿
池２６には、後述のように沈殿した活性汚泥を、生物反
応槽１１の前段部１１ｂに戻すための返送用管路２７が
設けられている。Outflow pipes 23 and 24 are connected to the anode reaction chamber 12 and the cathode chamber 20 at the subsequent stage thereof, respectively. These outflow lines 23 and 24 join one outflow line 25. This outflow line 25
At the downstream side reaches the sedimentation basin 26. The sedimentation basin 26 is provided with a return pipe 27 for returning the activated sludge settled as described later to the former stage 11 b of the biological reaction tank 11.

【００２１】上述のような構成からなる廃水処理設備１
０を用いて次のような廃水処理が行われる。まず、流入
水１を生物反応槽１１に導入する。生物反応槽１１の前
段部１１ａでは、活性汚泥中の微生物による分解で炭素
質の汚濁物質がおおむね除去されるが、アンモニアの酸
化はほとんど起こらない。これは、炭素質の汚濁物質生
物の分解能力を有する微生物の方が、アンモニアの酸化
能力を有する微生物より高い反応速度を有し、かつ、高
い酸素獲得能力を有すること、および、一部のアンモニ
アを酸化する能力を有する微生物は、有機物が存在する
場合には、アンモニアより有機物を優先的に分解する性
質を持つことによる。The wastewater treatment equipment 1 having the above-described configuration.
The following wastewater treatment is performed using 0. First, the inflow water 1 is introduced into the biological reaction tank 11. In the former stage 11a of the biological reaction tank 11, carbonaceous pollutants are substantially removed by the decomposition of microorganisms in the activated sludge, but oxidation of ammonia hardly occurs. This is because microorganisms capable of decomposing carbonaceous pollutant organisms have a higher reaction rate and higher oxygen acquisition ability than microorganisms capable of oxidizing ammonia, and that some ammonia Microorganisms that have the ability to oxidize organic matter have the property of decomposing organic matter preferentially over ammonia when present.

【００２２】この生物反応槽１１の前段部１１ａにおけ
る処理により、炭素質の汚濁物質がおおむね除去され、
アンモニアの酸化がほとんど起こっていない段階の１次
処理水および活性汚泥の混合物の一部を、陽極側流入管
路２１を経て、電極反応槽１２の陽極室１９に導入す
る。By the treatment in the front part 11a of the biological reaction tank 11, carbonaceous pollutants are substantially removed,
A part of the mixture of the primary treated water and the activated sludge at the stage where the ammonia oxidation hardly occurs is introduced into the anode chamber 19 of the electrode reaction tank 12 through the anode-side inflow pipe 21.

【００２３】一方、生物反応槽１１の後段部１１ｂで
は、主に微生物によるアンモニア態窒素の酸化が行われ
る。前段部１１ａないし後段部１１ｂで処理された２次
処理水は、陰極側流入管路２２を経て、電極反応槽１２
の陰極室２０に導入する。On the other hand, in the rear part 11b of the biological reaction tank 11, oxidation of ammonia nitrogen is mainly performed by microorganisms. The secondary treated water treated in the former part 11a or the latter part 11b passes through the cathode side inflow pipe 22 and passes through the electrode reaction tank 12
Into the cathode chamber 20.

【００２４】電極反応槽１２では、陽極１３および陰極
１４の間に電源１７からそれぞれ配線１５、１６を介し
て直流電圧を印加し、生物反応槽１１からの１次および
２次処理水に電流を流して電気分解を行う。電極反応槽
１２での電気分解により、陰極１４側では、下記式
（１）および（２）に示す反応が進行し、ＮＯｘ−Ｎが
分解される。In the electrode reaction tank 12, a DC voltage is applied between the anode 13 and the cathode 14 from the power supply 17 via wirings 15 and 16, respectively, and an electric current is applied to the primary and secondary treated water from the biological reaction tank 11. Perform electrolysis by flowing. By the electrolysis in the electrode reaction tank 12, the reactions shown in the following formulas (1) and (2) progress on the cathode 14 side, and NOx-N is decomposed.

【００２５】 2ＮＯ3 - ＋ 2Ｈ+ ＋ 5Ｈ2 → Ｎ2 ＋ 6Ｈ2 ０ （２） 一方、陽極１３側では、下式（３）に示す反応が進行
し、アンモニア態窒素が窒素ガスに酸化される。 2ＮＨ3 ＋ 6ＯＨ- →Ｎ2 ＋ 6Ｈ2 Ｏ＋ 6ｅ- （３） このよう電極反応槽１２の陽極室１９および陰極室２０
で処理された３次処理水および活性汚泥の混合物を、流
出管路２３、２４および流出管路２５を順次介して沈殿
池２６に導入する。沈殿池２６では、混合物中に含まれ
ている活性汚泥を沈殿させる。沈殿した活性汚泥を、返
送用管路２７を介して生物反応槽１１の前段部１１ａに
戻して再利用する。沈殿池２６で微生物が沈殿した後の
上澄み水は、最終処理水２８として放流される。通常、
最終処理水２８は、滅菌処理を施された後に放流され
る。2NO 3 − + 2H + + 5H 2 → N 2 + 6H 20 (2) On the anode 13 side, a reaction represented by the following formula (3) proceeds, and ammonia nitrogen is oxidized to nitrogen gas. You. 2NH 3 + 6OH − → N 2 + 6H 2 O + 6e − (3) Thus, the anode chamber 19 and the cathode chamber 20 of the electrode reaction tank 12.
The mixture of the tertiary treated water and the activated sludge treated in the step (1) is introduced into the sedimentation basin 26 through the outlet pipes 23 and 24 and the outlet pipe 25 sequentially. In the sedimentation basin 26, the activated sludge contained in the mixture is settled. The precipitated activated sludge is returned to the front stage 11a of the biological reaction tank 11 via the return pipe 27 and reused. The supernatant water after the microorganisms have settled in the sedimentation basin 26 is discharged as final treated water 28. Normal,
The final treated water 28 is discharged after being subjected to a sterilization treatment.

【００２６】上述のような本発明の第１実施形態に係る
廃水処理方法では、生物反応槽１１の前段部１１ａか
ら、前段部１１ａで炭素質の汚濁物質がおおむね除去さ
れ、アンモニアの酸化がほとんど起こっていない段階の
１次処理水および活性汚泥の混合物の一部が抜き取られ
ている。これにより、後段部１１ｂに送られる廃水の量
が削減されるために、生物反応槽１１の後段部１１ｂで
の廃水の滞留時間が長くなる。この結果、アンモニアの
生物学的な酸化処理に必要な反応時間を、比較的容積が
小さい生物反応槽でも十分に確保することができるの
で、生物反応槽１１でほぼ１００％のアンモニア態窒素
の酸化が行われる。In the wastewater treatment method according to the first embodiment of the present invention as described above, carbonaceous pollutants are substantially removed from the front part 11a of the biological reaction tank 11 in the front part 11a, and almost no oxidation of ammonia occurs. A portion of the mixture of primary effluent and activated sludge in the non-occurring stage has been withdrawn. Thereby, since the amount of wastewater sent to the latter part 11b is reduced, the residence time of the wastewater in the latter part 11b of the biological reaction tank 11 becomes longer. As a result, the reaction time necessary for the biological oxidation treatment of ammonia can be sufficiently ensured even in a relatively small-volume biological reaction tank. Is performed.

【００２７】このように後段部１１ｂで処理される廃水
の量を少なくすること、言い換えれば、生物反応槽１１
の水量負荷が軽減されることにより、アンモニア態窒素
の１００％分解に必要な生物反応槽１１の容積を小さく
することが可能である。このため、現存の施設の容積が
足らないと考えられている反応槽においてもほぼ１００
％のアンモニア態窒素の酸化が可能になる。また、新た
に施設を建設する場合にも、設計段階で小型の生物反応
層を採用することが可能である。このように第１実施形
態に係る廃水処理方法によれば、廃水処理施設の設備コ
ストを大幅に低減できる。As described above, the amount of wastewater treated in the post-stage portion 11b is reduced, in other words, the biological reaction tank 11
, The volume of the biological reaction tank 11 required for 100% decomposition of ammonia nitrogen can be reduced. For this reason, even in a reaction tank which is considered to have a shortage of existing facilities, almost 100
% Ammonia nitrogen can be oxidized. Also, when a new facility is constructed, it is possible to employ a small bioreactive layer at the design stage. As described above, according to the wastewater treatment method according to the first embodiment, the facility cost of the wastewater treatment facility can be significantly reduced.

【００２８】また、生物反応槽１１の前段部１１ａから
抜き取られた処理水および汚泥の混合物については、電
極反応槽１２の陽極室１９において、この混合物中に豊
富に含まれているアンモニア態窒素が、上記式（３）に
従って、窒素ガスへ酸化される。一方、生物反応槽１１
の後段部１１ｂから流出した、アンモニア態窒素をほと
んど含まないがＮＯｘ−Ｎを含む２次処理水に対して
は、電極反応槽１２の陰極室２０において、上記式
（１）および（２）に従って、ＮＯｘ−Ｎが窒素ガスに
分解される。The mixture of the treated water and the sludge extracted from the front stage 11a of the biological reaction tank 11 contains, in the anode chamber 19 of the electrode reaction tank 12, ammonia nitrogen which is abundantly contained in the mixture. Is oxidized to nitrogen gas according to the above equation (3). On the other hand, biological reaction tank 11
In the cathode chamber 20 of the electrode reaction tank 12, the secondary treatment water containing almost no ammonia nitrogen but containing NOx-N, which has flowed out of the rear stage 11b, is subjected to the above-mentioned formulas (1) and (2). , NOx-N are decomposed into nitrogen gas.

【００２９】このように電極反応槽１２では、上記式
（１）、（２）および（３）の反応が同時に進行する。
このため、電流が陽極１３と陰極１４の両方で利用され
る。つまり、上記説明した通り、従来の方法Ｉ、IIで
は、１モルのＮＯｘ−Ｎの還元に必要な水素を発生させ
るために、１０ファラデーの電流が必要であり、この電
流は陽極では有効利用されれていない。しかしながら、
この第１実施形態の方法では、陽極１３はアンモニア態
窒素を窒素ガスに酸化する能力を有する電極で構成され
ているため、この電流が陽極１３でも有効利用される。
これにより、この第１実施形態の方法では、陽極１３で
の電力の利用効率を２０％と仮定した場合、１０ファラ
デーの電流で１モルのＮＯｘ−Ｎの処理と同時に、０．
６７モルのアンモニア態窒素の処理が可能となる。よっ
て、窒素元素に着目すれば、方法Ｉ，IIでは１モルの窒
素の処理が行われた電力量によって、この第１実施形態
では１．６７モルの窒素の処理が行われることとなる。
陽極１３での効率が向上すればさらに大きな値となる。
以上説明したように、本発明の第１実施形態の廃水処理
方法によれば、従来の方法と比較して大幅な処理エネル
ギーの削減が可能となる。As described above, in the electrode reaction tank 12, the reactions of the above formulas (1), (2) and (3) proceed simultaneously.
For this reason, current is used for both the anode 13 and the cathode 14. That is, as described above, in the conventional methods I and II, a current of 10 Faraday is required in order to generate hydrogen required for reduction of 1 mol of NOx-N, and this current is effectively used in the anode. Not. However,
In the method according to the first embodiment, since the anode 13 is constituted by an electrode having an ability to oxidize ammonia nitrogen into nitrogen gas, this current is also effectively used at the anode 13.
Thus, in the method of the first embodiment, assuming that the power utilization efficiency at the anode 13 is 20%, the processing of 0.1 mol of NOx-N at a current of 10 Faraday and 0.1 mol of NOx-N are performed simultaneously.
67 mol of ammonia nitrogen can be treated. Therefore, if attention is paid to the nitrogen element, in the first embodiment, the processing of 1.67 mol of nitrogen is performed by the amount of electric power in which the processing of 1 mol of nitrogen is performed in the methods I and II.
If the efficiency at the anode 13 is improved, the value becomes even larger.
As described above, according to the wastewater treatment method of the first embodiment of the present invention, it is possible to significantly reduce the treatment energy as compared with the conventional method.

【００３０】なお、陽極１３および陰極１４での電極反
応速度は、生物学的反応速度に比べて１オーダー以上大
きいので、比較的小型の電極反応槽１１を採用できる。
このため、生物反応槽１１および電極反応槽１２を組み
合わせても、上記説明した生物反応槽１１の小型化のメ
リットは損なわれることがない。Since the electrode reaction speed at the anode 13 and the cathode 14 is at least one order of magnitude higher than the biological reaction speed, a relatively small electrode reaction tank 11 can be employed.
For this reason, even if the biological reaction tank 11 and the electrode reaction tank 12 are combined, the advantage of downsizing the biological reaction tank 11 described above is not impaired.

【００３１】また、電極反応速度は、電流を制御するこ
とにより自由にコントロール可能である。このため、流
入水１の量および性状に合わせて、または、実際の処理
水の水質と要求処理水質の関係から、電極反応槽１２へ
の１次および２次処理水の投入量、生物反応槽１１の前
段部１１ａにおける１次処理水の取水位置並びに電気分
解の電流量および電圧の制御を行うことによって、処理
エネルギーをさらに低減できると共に、処理水の水質の
変動幅を小さくすることが可能である。The electrode reaction rate can be freely controlled by controlling the current. For this reason, according to the amount and properties of the influent water 1 or from the relationship between the actual treated water quality and the required treated water quality, the amounts of the primary and secondary treated water supplied to the electrode reaction tank 12 and the biological reaction tank By controlling the intake position of primary treated water and the amount and voltage of electrolysis in the first stage 11a of the eleventh stage, the treatment energy can be further reduced and the fluctuation range of the quality of treated water can be reduced. is there.

【００３２】以上説明したように、本発明の第１実施形
態に係る廃水処理方法によれば、従来の廃水処理方法に
比べて、反応槽の容積を低減できるとともに、処理エネ
ルギーを削減し、かつ、処理水の水質の変動幅を小さく
できる。As described above, according to the wastewater treatment method according to the first embodiment of the present invention, the volume of the reaction tank can be reduced, the treatment energy can be reduced, and In addition, the fluctuation range of the quality of the treated water can be reduced.

【００３３】次に、図２を参照して本発明の廃水処理方
法の第２実施形態について説明する。図２中の符号のう
ち、図１に示す符号と同じものは、特に説明する場合を
除き、第１実施形態に関して説明した部材と同じものを
示す。Next, a second embodiment of the wastewater treatment method of the present invention will be described with reference to FIG. 2, the same reference numerals as those shown in FIG. 1 indicate the same members as those described in the first embodiment, unless otherwise specified.

【００３４】この第２実施形態に係る廃水処理方法で用
いられる廃水処理設備３０では、第１実施形態と同様
に、標準活性汚泥法の生物反応槽１１が用いられる。生
物反応槽１１の前段部１１ａには、取水用管路３１が接
続されている。この取水用管路３１の出口側には、第１
沈殿池３２が設けられている。第１沈殿池３２には、上
澄み液を電極反応槽１２の陽極室１９に導入する陽極側
流入管路３３が接続されている。また、第１沈殿池３２
には、沈殿した活性汚泥を生物反応槽１１の前段部１１
ａに送り返す第１返送用管路３４が設けられている。In the wastewater treatment equipment 30 used in the wastewater treatment method according to the second embodiment, the biological reaction tank 11 of the standard activated sludge method is used as in the first embodiment. A water intake conduit 31 is connected to the front stage 11 a of the biological reaction tank 11. At the outlet side of the water intake conduit 31, a first
A settling basin 32 is provided. The first settling basin 32 is connected to an anode-side inflow pipe 33 for introducing the supernatant into the anode chamber 19 of the electrode reaction tank 12. In addition, the first sedimentation basin 32
Activated sludge that has settled is transferred to the former stage 11 of the biological reaction tank 11.
A first return line 34 to be sent back to a is provided.

【００３５】一方、生物反応槽１１の後段部１１ｂに
は、送通用管路３５が設けられ、この送通用管路３５の
出口側には、第２沈殿池３６が設けられている。この第
２沈殿池３６には、上澄み液を電極反応槽１２の陰極室
２０へ導入するための陰極側流入管路３７が設けられて
いる。また、第２沈殿池３６で沈殿した微生物を生物反
応槽１１の前段部１１ａに送り返すための第２返送用管
路３８が設けられている。On the other hand, a transmission pipe 35 is provided in the rear part 11b of the biological reaction tank 11, and a second sedimentation tank 36 is provided on the outlet side of the communication pipe 35. The second settling tank 36 is provided with a cathode-side inflow conduit 37 for introducing the supernatant into the cathode chamber 20 of the electrode reaction tank 12. A second return pipe 38 is provided for returning the microorganisms precipitated in the second sedimentation basin 36 to the former stage 11 a of the biological reaction tank 11.

【００３６】第２実施形態では、陰極１４として、微生
物を固定した電極またはＮＯｘ−Ｎを窒素ガスに還元す
る能力を有する電極を用いている。電極反応槽１２の陽
極室１９および陰極室２０の後段部には、それぞれ、流
出管路３９、４０が接続され、流出管路３９、４０は一
つの流出管路４１に合流している。In the second embodiment, as the cathode 14, an electrode on which microorganisms are fixed or an electrode capable of reducing NOx-N to nitrogen gas is used. Outflow pipes 39 and 40 are connected to the rear part of the anode chamber 19 and the cathode chamber 20 of the electrode reaction tank 12, respectively, and the outflow pipes 39 and 40 merge into one outflow pipe 41.

【００３７】上述のような廃水処理設備３０を用いて次
のような廃水処理が行われる。まず、流入水１を生物反
応槽１１に導入する。生物反応槽１１の前段部１１ａか
ら、炭素質の汚濁物質がおおむね除去され、アンモニア
の酸化がほとんど起こっていない段階の１次処理水およ
び活性汚泥の混合物の一部を、取水用管路３１を介し
て、第１沈殿池３２に導入する。この第１沈殿池３２に
おいて、混合物中の活性汚泥を沈殿させる。第１沈殿池
３２で得られた上澄み液を、陽極側流入管路３３を経
て、電極反応槽１２の陽極室１９に導入する。一方、沈
殿した活性汚泥は、第１返送用管路３４を介して、生物
反応槽１１の前段部１１ａに送り返し、再利用する。The following wastewater treatment is performed using the wastewater treatment equipment 30 as described above. First, the inflow water 1 is introduced into the biological reaction tank 11. A part of the mixture of the primary treated water and the activated sludge at the stage where the carbonaceous pollutants are substantially removed and the oxidation of ammonia hardly occurs from the front part 11a of the biological reaction tank 11 is passed through the intake pipe 31. Through the first settling basin 32. In the first settling tank 32, the activated sludge in the mixture is settled. The supernatant obtained in the first settling tank 32 is introduced into the anode chamber 19 of the electrode reaction tank 12 through the anode-side inflow pipe 33. On the other hand, the settled activated sludge is sent back to the former stage 11a of the biological reaction tank 11 via the first return pipe 34, and is reused.

【００３８】一方、生物反応槽１１の後段部１１ｂで
は、主に微生物によるアンモニア態窒素の酸化が行われ
る。前段部１１ａないし後段部１１ｂで処理された２次
処理水および活性汚泥の混合物を、送通用管路３５を経
て、第２沈殿池３６に導入する。この第２沈殿池３６で
は、混合物中の活性汚泥が沈殿させる。第２沈殿池３６
で得られた上澄み液を、陰極側流入管路３７を介して、
電極反応槽１２の陰極室２０に導入する。一方、第２沈
殿池３６で沈殿した活性汚泥は、第２返送用管路３８を
介して、生物反応槽１１の前段部１１ａに送り返し、再
利用する。On the other hand, in the rear stage 11b of the biological reaction tank 11, ammonia is mainly oxidized by microorganisms. The mixture of the secondary treatment water and the activated sludge treated in the former part 11a or the latter part 11b is introduced into the second sedimentation basin 36 through the conduit 35 for communication. In the second sedimentation basin 36, activated sludge in the mixture is settled. Second sedimentation basin 36
Through the cathode-side inflow conduit 37,
It is introduced into the cathode chamber 20 of the electrode reaction tank 12. On the other hand, the activated sludge settled in the second settling tank 36 is sent back to the former stage 11a of the biological reaction tank 11 through the second return pipe 38 and reused.

【００３９】電極反応槽１２では、上澄み液に対して、
第１実施形態と同様に、電流を流して電気分解を行う。
電極反応槽１２での電気分解により、陰極１４側では、
上記式（１）および（２）に示す反応が進行し、ＮＯｘ
−Ｎが窒素ガスに還元される。一方、陽極１３側では、
上式（３）に示す反応が進行し、アンモニア態窒素が窒
素ガスに酸化される。In the electrode reaction tank 12, the supernatant is
As in the first embodiment, electrolysis is performed by passing a current.
By electrolysis in the electrode reaction tank 12, on the cathode 14 side,
The reaction represented by the above formulas (1) and (2) proceeds, and NOx
-N is reduced to nitrogen gas. On the other hand, on the anode 13 side,
The reaction represented by the above formula (3) proceeds, and ammonia nitrogen is oxidized to nitrogen gas.

【００４０】このよう電極反応槽１２の陽極室１９およ
び陰極室２０で処理された３次処理水を、流出管路３
９、４０および流出管路４１を順次介して、最終処理水
として放流させる。通常最終処理水は、滅菌処理を施さ
れた後に放流される。The tertiary treated water treated in the anode chamber 19 and the cathode chamber 20 of the electrode reaction tank 12 is supplied to the outlet pipe 3.
The water is discharged as final treated water through the pipes 9 and 40 and the outflow pipe 41 in order. Usually, the final treated water is released after being subjected to a sterilization treatment.

【００４１】以上説明した第２実施形態に係る廃水処理
方法では、第１および第２沈殿池３１、３６において、
生物反応槽１１からの混合液から微生物を含む活性汚泥
を沈殿除去しているので、電極反応槽１２へ微生物は流
入しない。このため、微生物の活性は、大電流を陽極１
３および陰極１４の間に流すと低下することがあるが、
この第２実施形態では、陰極１４として、ＮＯｘ−Ｎを
窒素ガスに還元する能力を有する電極を用いた場合に
は、電極反応槽１２の中には微生物は関与しないので、
大電流を流しても問題ない。この結果、第２実施形態に
係る廃水処理方法は、生物反応槽１１を小型化できる等
の第１実施形態の方法と同様の効果に加え、陽極１３お
よび陰極１４の間に大電流を流し、電気反応槽１２の処
理能力を増大させることができるという効果を奏する。In the wastewater treatment method according to the second embodiment described above, the first and second sedimentation ponds 31, 36
Since activated sludge containing microorganisms is precipitated and removed from the mixed solution from the biological reaction tank 11, the microorganisms do not flow into the electrode reaction tank 12. For this reason, the activity of the microorganism is such that a large current is applied to the anode 1
When flowing between the cathode 3 and the cathode 14, it may decrease,
In the second embodiment, when an electrode having the ability to reduce NOx-N to nitrogen gas is used as the cathode 14, microorganisms do not participate in the electrode reaction tank 12, so that
There is no problem even if a large current flows. As a result, in the wastewater treatment method according to the second embodiment, in addition to the same effect as the method of the first embodiment such that the biological reaction tank 11 can be downsized, a large current flows between the anode 13 and the cathode 14, There is an effect that the processing capacity of the electric reaction tank 12 can be increased.

【００４２】次に、図３を参照して本発明の廃水処理方
法の第３実施形態について説明する。図３中の符号のう
ち、図１および図２に示す符号と同じものは、特に説明
する場合を除き、第１実施形態および第２実施形態に関
して説明した部材と同じものを示す。Next, a third embodiment of the wastewater treatment method of the present invention will be described with reference to FIG. 3, the same reference numerals as those shown in FIGS. 1 and 2 indicate the same members as those described with respect to the first embodiment and the second embodiment, unless otherwise specified.

【００４３】図３に示す廃水処理設備５０を用いた第３
実施形態に係る廃水処理方法は、以下の点を除き、上述
の第２実施形態に係る廃水処理方法と同様である。 ・生物反応槽１１の後段部１１ｂから流出した２次処理
水および活性汚泥の混合物を、陰極側流入管路４２を介
して陰極室２０に直接導入すること、および、 ・陰極室２０で電気分解を受けた２次処理水および活性
汚泥の混合物を、排出管路３９の途中に設けられた第２
沈殿池４３に導入し、この第２沈殿池４３で混合物中の
活性汚泥を沈殿させ、上澄み液を陽極室１９で電気分解
された３次処理水と共に最終処理水として放流し、か
つ、沈殿した活性汚泥を第２返送用管路４４を介して生
物反応槽１１の前段部１１ａに返送して再利用するこ
と。A third example using the wastewater treatment equipment 50 shown in FIG.
The wastewater treatment method according to the embodiment is the same as the wastewater treatment method according to the above-described second embodiment, except for the following points. -Directly introducing the mixture of the secondary treatment water and the activated sludge flowing out from the rear part 11b of the biological reaction tank 11 into the cathode chamber 20 through the cathode-side inflow pipe 42; and-Electrolysis in the cathode chamber 20 The mixture of the secondary treated water and the activated sludge that has received the
Activated sludge in the mixture was settled in the sedimentation tank 43, and the supernatant liquid was discharged as final treatment water together with the tertiary treatment water electrolyzed in the anode chamber 19, and settled. Activated sludge is returned to the front part 11a of the biological reaction tank 11 via the second return pipe 44 for reuse.

【００４４】このような第３実施形態に係る廃水処理方
法によれば、第２実施形態の方法と比較して、陰極１４
自体に微生物を固定しなくとも、活性汚泥中に存在する
微生物によって処理ができるという利点がある。According to the wastewater treatment method according to the third embodiment, as compared with the method of the second embodiment, the cathode 14
There is an advantage that the treatment can be performed by the microorganisms present in the activated sludge without fixing the microorganisms themselves.

【００４５】以上説明した第１〜第３実施形態に係る廃
水処理方法では、いずれも生物反応槽１１に標準活性汚
泥法を適用した。しかし、例えば、回転円板法または流
動床法のような生物学的な好気性廃水処理方法を適用で
きる。In the wastewater treatment methods according to the first to third embodiments described above, the standard activated sludge method was applied to the biological reaction tank 11. However, biological aerobic wastewater treatment methods such as, for example, a rotating disk method or a fluidized bed method can be applied.

【００４６】次に、本発明の第４実施形態に係る廃水処
理方法について説明する。図４は、第４実施形態に係る
廃水処理方法に用いられる廃水処理設備を示す概略図で
ある。図４中６１は、生物反応槽であり、硝化−内生脱
窒法を適用したものである。生物反応槽６１は、好気部
６２と、好気部６２の後段に設けられた嫌気部（無酸素
槽）６３を具備する。生物反応槽６１の前段に設けられ
た好気部６２の底部には、散気装置（図示せず）が配置
されており、散気装置から酸素含有ガス（通常空気）が
吹き込まれ、好気部６２内全体が好気条件下に置かれて
いる。一方、生物反応槽６１の後段に設けられた嫌気部
６３は、酸素含有ガスを吹き込まず撹拌だけを行うこと
により、無酸素状態になっている。生物反応槽６１の内
部には、炭素質の汚濁物質生物の分解能力を有する微生
物やアンモニアの酸化能力を有する微生物を含有する活
性汚泥が浮遊している。生物反応槽６１には、処理前の
流入水１が供給されるようになっている。Next, a wastewater treatment method according to a fourth embodiment of the present invention will be described. FIG. 4 is a schematic diagram illustrating a wastewater treatment facility used in the wastewater treatment method according to the fourth embodiment. In FIG. 4, reference numeral 61 denotes a biological reaction tank to which a nitrification-endogenous denitrification method is applied. The biological reaction tank 61 includes an aerobic section 62 and an anaerobic section (anoxic tank) 63 provided at a stage subsequent to the aerobic section 62. An air diffuser (not shown) is disposed at the bottom of the aerobic section 62 provided in the preceding stage of the biological reaction tank 61, and an oxygen-containing gas (normal air) is blown from the air diffuser to aerobic. The entire part 62 is placed under aerobic conditions. On the other hand, the anaerobic part 63 provided at the latter stage of the biological reaction tank 61 is in an oxygen-free state by performing only stirring without blowing the oxygen-containing gas. Activated sludge containing microorganisms capable of decomposing carbonaceous pollutant organisms and microorganisms capable of oxidizing ammonia floats inside the biological reaction tank 61. The biological reaction tank 61 is supplied with the inflow water 1 before the treatment.

【００４７】一方、図４中６４は電極反応槽である。電
極反応槽６４の内部には、一対の陽極６５および陰極６
６が互いに対向して配置されている。陽極６５は、第１
実施形態と同様に、アンモニア態窒素を窒素ガスに酸化
する能力を有する電極で構成されている。一方、陰極６
６は、第１実施形態と同様に、水を水素ガスに還元する
能力を有する電極で構成される。On the other hand, reference numeral 64 in FIG. 4 denotes an electrode reaction tank. Inside the electrode reaction tank 64, a pair of anode 65 and cathode 6
6 are arranged opposite to each other. The anode 65 is the first
As in the embodiment, it is composed of an electrode having the ability to oxidize ammonia nitrogen to nitrogen gas. On the other hand, the cathode 6
Reference numeral 6 is an electrode having the ability to reduce water to hydrogen gas, as in the first embodiment.

【００４８】上記陽極６５および陰極６６は、それぞれ
配線６７、６８を介して電源６９の陽極側および陰極側
にそれぞれ接続されている。電極反応槽６４内は、導電
性隔膜７０により、陽極室７１および陰極室７２に分割
されている。この導電性隔膜１８は、第１実施形態と同
様に、電気を通すが廃水中の水分子、固形物、アンモニ
ア態窒素およびＮＯｘ−Ｎを実質的に透過しない材質か
らなる。The anode 65 and the cathode 66 are connected to the anode side and the cathode side of a power source 69 via wirings 67 and 68, respectively. The inside of the electrode reaction tank 64 is divided by a conductive diaphragm 70 into an anode chamber 71 and a cathode chamber 72. As in the first embodiment, the conductive diaphragm 18 is made of a material that conducts electricity but does not substantially transmit water molecules, solids, ammonia nitrogen, and NOx-N in wastewater.

【００４９】生物反応槽６１の好気部６２の前段部６２
ａには、陽極側流入管路７３が接続され、電極反応槽６
４の陽極室７０へ通じている。また、生物反応槽６１の
嫌気部６３の前段部６３ａには、陰極側流入管路７４の
一端部が接続されている。この陰極側流入管路７４の他
端部は、電極反応槽６４の陰極室７２に接続されてい
る。The front part 62 of the aerobic part 62 of the biological reaction tank 61
a, an anode-side inflow pipe 73 is connected to the electrode reaction tank 6.
4 to the anode chamber 70. Further, one end of a cathode-side inflow conduit 74 is connected to a front stage 63 a of the anaerobic section 63 of the biological reaction tank 61. The other end of the cathode-side inflow pipe 74 is connected to the cathode chamber 72 of the electrode reaction tank 64.

【００５０】さらに、生物反応槽６１の嫌気部６３の後
段部６３ｂには、送通用管路７５を介して沈殿池７６が
接続されている。電極反応槽６４の陽極室７１および陰
極室７２の後段部には、それぞれ、流出管路７７、７８
がそれぞれ接続されている。これらの流出管路７７、７
８は一つの流出管路７９に合流している。この流出管路
７９の後流側端部は、沈殿池７６まで達している。沈殿
池７６には、沈殿した活性汚泥を生物反応槽６１の好気
部６２に戻すための返送用管路８０が設けられている。Further, a sedimentation basin 76 is connected to a rear part 63 b of the anaerobic part 63 of the biological reaction tank 61 via a communication pipe 75. Outflow conduits 77 and 78 are provided in the rear part of the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64, respectively.
Are connected respectively. These outflow lines 77, 7
8 merges into one outlet line 79. The downstream end of the outflow pipe 79 reaches the sedimentation basin 76. The settling basin 76 is provided with a return pipe 80 for returning the settled activated sludge to the aerobic part 62 of the biological reaction tank 61.

【００５１】上述のような構成からなる廃水処理設備６
０を用いて次のような廃水処理が行われる。まず、流入
水１を生物反応槽６１の好気部６２に導入する。好気部
６２では、活性汚泥中の微生物の好気条件下での反応に
より、流入水１中のアンモニア態窒素がＮＯｘ−Ｎまで
酸化される。さらに後段の嫌気部６３では、微生物の嫌
気条件下での反応により、ＮＯｘ−Ｎが窒素ガスに還元
される。The wastewater treatment facility 6 having the above-described configuration.
The following wastewater treatment is performed using 0. First, the inflow water 1 is introduced into the aerobic section 62 of the biological reaction tank 61. In the aerobic part 62, the ammonia nitrogen in the influent 1 is oxidized to NOx-N by the reaction of the microorganisms in the activated sludge under aerobic conditions. Further, in the subsequent anaerobic section 63, NOx-N is reduced to nitrogen gas by the reaction under the anaerobic condition of the microorganism.

【００５２】ここで、好気部６２の前段部６２ａから、
炭素質の汚濁物質がおおむね除去され、アンモニアの酸
化がほとんど起こっていない段階の１次処理水および活
性汚泥の混合物の一部を、陽極側流入管路７３を介して
電極反応槽６４の陽極室７１に導入する。また、嫌気部
６３の前段部６３ａから、好気部６２においてアンモニ
ア態窒素がほとんど１００％ＮＯｘ−Ｎに酸化された段
階の２次処理水および活性汚泥の混合物の一部を、陰極
側流入管路７４を介して電極反応槽６４の陰極室７２に
導入する。Here, from the front part 62a of the aerobic part 62,
A part of the mixture of the primary treated water and the activated sludge at the stage where the carbonaceous pollutants are substantially removed and the oxidation of ammonia hardly occurs is transferred to the anode chamber of the electrode reaction tank 64 via the anode-side inflow pipe 73. 71. Further, a part of the mixture of the secondary treated water and the activated sludge at the stage where the ammonia nitrogen is almost oxidized to 100% NOx-N in the aerobic part 62 from the former part 63a of the anaerobic part 63 is transferred to the cathode side inlet pipe. It is introduced into the cathode chamber 72 of the electrode reaction tank 64 via the passage 74.

【００５３】また、嫌気部６３から後段部６３ｂまでの
間に、ＮＯｘ−Ｎがほとんど１００％窒素ガスに還元さ
れた３次処理水および活性汚泥の混合物は、配送用管路
７５を介して沈殿池７６に導入する。Between the anaerobic section 63 and the downstream section 63b, a mixture of the tertiary treated water and the activated sludge in which NOx-N has been reduced to almost 100% nitrogen gas is settled via the delivery line 75. It is introduced into the pond 76.

【００５４】電極反応槽６４では、陽極６５および陰極
６６の間に電源６９からそれぞれ配線６８、６９を介し
て直流電圧を印加し、生物反応槽６１からの１次処理水
および２次処理水に電流を流して電気分解を行う。電極
反応槽６４での電気分解により、陰極６６側では、上記
式（１）および（２）に示す反応が進行し、ＮＯｘ−Ｎ
が窒素ガスに還元される。一方、陽極６５側では、上記
式（３）に示す反応が進行し、アンモニア態窒素が窒素
ガスに酸化される。In the electrode reaction tank 64, a DC voltage is applied between the anode 65 and the cathode 66 from the power supply 69 via the wirings 68 and 69, respectively, to supply the primary treated water and the secondary treated water from the biological reaction tank 61. Electrolysis is carried out by passing an electric current. By the electrolysis in the electrode reaction tank 64, the reactions represented by the above formulas (1) and (2) proceed on the cathode 66 side, and NOx-N
Is reduced to nitrogen gas. On the other hand, on the anode 65 side, the reaction represented by the above formula (3) proceeds, and ammonia nitrogen is oxidized to nitrogen gas.

【００５５】このように電極反応槽６４の陽極室７１お
よび陰極室７２で処理された処理水および活性汚泥の混
合物を、流出管路７７、７８および流出管路７９を順次
介して沈殿池７６に導入する。沈殿池７６では、混合物
中の活性汚泥を沈殿させる。沈殿した活性汚泥を、返送
用管路８０を介して生物反応槽６１の好気部６２に戻し
て再利用する。一方、沈殿池２６で活性汚泥が沈殿した
後の上澄み水は、最終処理水８１として放流される。通
常、最終処理水８１は、滅菌処理を施された後に放流さ
れる。The mixture of the treated water and the activated sludge treated in the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64 as described above is sequentially passed through outflow pipes 77 and 78 and outflow pipe 79 to a sedimentation tank 76. Introduce. In the settling basin 76, the activated sludge in the mixture is settled. The precipitated activated sludge is returned to the aerobic part 62 of the biological reaction tank 61 via the return pipe 80 for reuse. On the other hand, the supernatant water after the activated sludge has settled in the sedimentation basin 26 is discharged as final treated water 81. Usually, the final treated water 81 is discharged after being subjected to a sterilization treatment.

【００５６】上述のように第４実施形態にかかる廃水処
理方法によれば、生物反応槽６１の好気部６２の前段部
６２ａから、炭素質の汚濁物質がおおむね除去され、ア
ンモニアの酸化がほとんどおこっていない段階の１次処
理水および活性汚泥の一部を抜き取る。これにより、好
気部６２の後段部６２ｂに流入する水量が減少し、後段
部６２ｂでの水の滞留時間が長くなる。このため、生物
反応槽６１の好気部６２の容積が従来のように小さくて
も、後段部６２ｂにおいて、廃水中のほぼ１００％のア
ンモニア態窒素が酸化され、窒素ガスとなる。As described above, according to the wastewater treatment method according to the fourth embodiment, carbonaceous pollutants are substantially removed from the front part 62a of the aerobic part 62 of the biological reaction tank 61, and almost no oxidation of ammonia occurs. A part of the primary treatment water and the activated sludge at the stage where no occurrence has occurred is withdrawn. As a result, the amount of water flowing into the rear part 62b of the aerobic part 62 decreases, and the residence time of water in the rear part 62b increases. For this reason, even if the volume of the aerobic part 62 of the biological reaction tank 61 is small as in the prior art, almost 100% of the ammonia nitrogen in the wastewater is oxidized into nitrogen gas in the latter part 62b.

【００５７】また、生物反応槽６１の嫌気部６３の前段
部６３ａからは、好気部６２でアンモニア酸化処理を受
けた２次処理水および活性汚泥の混合物の一部を、陰極
側流入管路７４を介して電極反応槽６４の陰極室７２に
導入する。これにより、嫌気部６３で処理される水量が
低減され、無酸素の嫌気条件下の嫌気部６３での廃水の
滞留時間が長くなる。この結果、嫌気条件下での微生物
による還元反応により、ほぼ１００％のアンモニア態窒
素が還元され、窒素ガスになる。From the front stage 63a of the anaerobic part 63 of the biological reaction tank 61, a part of the mixture of the secondary treated water and the activated sludge which has been subjected to the ammonia oxidation treatment in the aerobic part 62 is supplied to the cathode side inflow pipe. It is introduced into the cathode chamber 72 of the electrode reaction tank 64 via 74. Thereby, the amount of water treated in the anaerobic section 63 is reduced, and the residence time of the wastewater in the anaerobic section 63 under anoxic anaerobic condition is lengthened. As a result, almost 100% of ammonia nitrogen is reduced to nitrogen gas by a reduction reaction by microorganisms under anaerobic conditions.

【００５８】好気部６２の前段部６２ａおよび嫌気部６
３の前段部６３ａから抜き取られた１次処理水および２
次処理水に対しては、第１実施形態と同様に、それぞ
れ、電極反応槽６４の陽極室７１および陰極室７２で電
気分解による処理が施される。この電気分解では、第１
実施形態に関して説明した通り、上記式（１）、（２）
および（３）の反応が同時に進行する。このため、電流
が陽極１３と陰極１４の両方で利用されるので、従来の
方法と比較して大幅に処理エネルギーを削減できる。The front part 62a of the aerobic part 62 and the anaerobic part 6
Primary treated water extracted from the front stage 63a of 3 and 2
The next treatment water is subjected to electrolysis treatment in the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64, respectively, as in the first embodiment. In this electrolysis, the first
As described in the embodiment, the above equations (1) and (2)
And the reaction of (3) proceeds simultaneously. For this reason, since the current is used for both the anode 13 and the cathode 14, the processing energy can be significantly reduced as compared with the conventional method.

【００５９】以上説明したように、この第４実施形態の
廃水処理方法によれば、第１実施形態で説明した活性汚
泥法の場合と同様に、硝化−内生脱窒法を適用した生物
反応槽６１の好気部６２および嫌気部６３において十分
な酸化および還元反応に必要な容積を小さくできるた
め、従来の廃水処理方法と比較して、同等またはより小
さい生物反応槽を用いて、廃水中の汚濁物質を十分に除
去できる。また、電極反応槽６４での電気分解の消費エ
ネルギーも削減できる。As described above, according to the wastewater treatment method of the fourth embodiment, similar to the case of the activated sludge method described in the first embodiment, the biological reaction tank to which the nitrification-endogenous denitrification method is applied. Since the volume required for a sufficient oxidation and reduction reaction in the aerobic part 62 and the anaerobic part 63 of 61 can be reduced, compared with the conventional wastewater treatment method, the same or smaller biological reaction tank is used to reduce the volume of wastewater. Pollutants can be sufficiently removed. Further, the energy consumption of the electrolysis in the electrode reaction tank 64 can be reduced.

【００６０】次に図５を参照して本発明の第５実施形態
に係る廃水処理方法について説明する。図５中に示す符
号のうち、図４に示す符号と同じものは、特に説明する
場合を除き、第４実施形態に関して説明した部材と同じ
ものを示す。Next, a wastewater treatment method according to a fifth embodiment of the present invention will be described with reference to FIG. The same reference numerals as those shown in FIG. 4 among the reference numerals shown in FIG. 5 indicate the same members as those described in the fourth embodiment, unless otherwise specified.

【００６１】この第５実施形に係る廃水処理方法で用い
られる廃水処理設備９０は、次の点が図４に示す廃水処
理設備６０と相違する。第１に、生物反応槽６１の好気
部６２の前段部６２ａから１次処理水および活性汚泥の
混合物を抜き取るための陽極側流入管路７３の途中に、
第２の沈殿池９１が設けられている。また、沈殿池９１
には、沈殿した活性汚泥を好気部６２に送り返すための
返送用管路９２が設けられている。The wastewater treatment equipment 90 used in the wastewater treatment method according to the fifth embodiment differs from the wastewater treatment equipment 60 shown in FIG. First, in the middle of the anode-side inflow pipe 73 for extracting the mixture of the primary treatment water and the activated sludge from the former stage 62a of the aerobic part 62 of the biological reaction tank 61,
A second settling basin 91 is provided. In addition, sedimentation basin 91
Is provided with a return pipe 92 for returning the precipitated activated sludge to the aerobic part 62.

【００６２】第２に、生物反応槽６１の嫌気部６３の前
段部６３ａから２次処理水および活性汚泥の混合物を抜
き取るための陰極側流入管路７４の途中には、第３の沈
殿池９３が設けられている。この沈殿池９３には、返送
用管路９４が接続され、この返送用管路９４は、第２の
沈殿池９１に接続された返送用管路９２に合流してい
る。Secondly, a third sedimentation tank 93 is provided in the middle of the cathode-side inflow conduit 74 for extracting a mixture of the secondary treatment water and the activated sludge from the former stage 63a of the anaerobic part 63 of the biological reaction tank 61. Is provided. A return line 94 is connected to the sedimentation basin 93, and the return line 94 joins a return line 92 connected to the second sedimentation basin 91.

【００６３】第３に、電極反応槽６４の陽極室７１およ
び陰極室７２にそれぞれ接続された流出管路７７、７８
は、流出管路９５に合流し、電極反応槽６４で処理され
た水は、流出管路７７、７８および流出管路９５を経
て、第１の沈殿池７６からの水と共に、最終処理水８１
として放出されるようになっている。Third, outflow conduits 77 and 78 connected to the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64, respectively.
Merges into the outflow line 95, and the water treated in the electrode reaction tank 64 passes through the outflow lines 77, 78 and the outflow line 95, together with the water from the first sedimentation tank 76, and the final treated water 81.
It is to be released as.

【００６４】上述の廃水処理設備９０を用いた第５実施
形態に係る廃水処理方法では、生物処理槽６１の好気部
６２の前段部６２ａから抜き取られた１次処理水および
活性汚泥の混合物を、陽極側流入管路７２の途中に設け
られた沈殿池９１に導入し、この沈殿池９１において混
合物中の活性汚泥を沈殿分離する。沈殿した活性汚泥
は、搬送用管路９２を介して好気部６２の前段部６２ａ
に送り返して再利用に供する。一方、沈殿池９１で活性
汚泥が分離された１次処理水を、陽極側流入管路７２を
介して、電極反応槽６４の陽極室７１に導入する。In the wastewater treatment method according to the fifth embodiment using the above-described wastewater treatment equipment 90, the mixture of the primary treated water and the activated sludge extracted from the front part 62a of the aerobic part 62 of the biological treatment tank 61 is used. The activated sludge in the mixture is settled and separated in the sedimentation basin 91 provided in the middle of the anode-side inflow pipe 72. The settled activated sludge is transferred to the pre-stage 62 a of the aerobic portion 62 through the conveying pipe 92.
And send it back for reuse. On the other hand, the primary treated water from which the activated sludge has been separated in the sedimentation basin 91 is introduced into the anode chamber 71 of the electrode reaction tank 64 via the anode-side inflow pipe 72.

【００６５】同様に、嫌気部６３の前段部６３ａから抜
き取られた２次処理水および活性汚泥の混合物を、陰極
側流入管路７４の途中に設けられた沈殿池９３に導入
し、この沈殿池９３において混合物中の活性汚泥を沈殿
分離する。沈殿した活性汚泥は、搬送用管路９２および
９３を介して好気部６２の前段部６２ａに送り返して再
利用に供する。一方、沈殿池９３で活性汚泥が分離され
た２次処理水を、陰極側流入管路７４を介して電極反応
槽６４の陰極室７２に導入する。Similarly, the mixture of the secondary treated water and the activated sludge extracted from the former stage 63a of the anaerobic section 63 is introduced into the sedimentation basin 93 provided in the middle of the cathode side inflow pipe 74, At 93, the activated sludge in the mixture is settled off. The precipitated activated sludge is sent back to the front part 62a of the aerobic part 62 through the conduits 92 and 93 for reuse. On the other hand, the secondary treated water from which activated sludge has been separated in the sedimentation basin 93 is introduced into the cathode chamber 72 of the electrode reaction tank 64 via the cathode-side inflow pipe 74.

【００６６】このように電極反応槽６４の陽極室７１お
よび陰極室７２には、活性汚泥を含まない１次および２
次処理水を導入するため、電極反応槽６４へ微生物は流
入しない。このため、微生物の活性は、大電流を陽極６
７および陰極６８の間に流すと低下することがあるが、
この第５実施形態では、陰極６７として、ＮＯｘ−Ｎを
窒素ガスに還元する能力を有する電極を用いた場合に
は、電極反応槽６４の中には微生物は関与しないので、
大電流を流しても問題ない。この結果、第５実施形態に
係る廃水処理方法は、生物反応槽６１を小型化できる等
の第４実施形態の方法と同様の効果に加え、陽極６７お
よび陰極６８の間に大電流を流し、電気反応槽６４の処
理能力を増大させることができるという効果を奏する。As described above, the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64 have the primary and secondary cells not containing activated sludge.
Microbes do not flow into the electrode reaction tank 64 because the next treatment water is introduced. For this reason, the activity of the microorganism is such that a large electric current
When flowing between the cathode 7 and the cathode 68, it may decrease,
In the fifth embodiment, when an electrode having the ability to reduce NOx-N to nitrogen gas is used as the cathode 67, microorganisms do not participate in the electrode reaction tank 64.
There is no problem even if a large current flows. As a result, the wastewater treatment method according to the fifth embodiment has the same effect as the method of the fourth embodiment, such as being able to reduce the size of the biological reaction tank 61, and allows a large current to flow between the anode 67 and the cathode 68, There is an effect that the processing capacity of the electric reaction tank 64 can be increased.

【００６７】次に、図６を参照して本発明の第６実施形
態にかかる廃水処理方法について説明する。図６中に示
す符号のうち、図４および５に示す符号と同じものは、
特に説明する場合を除き、第４、５実施形態に関して説
明した部材と同じものを示す。図６に示す廃水処理設備
１００は、第５実施形態の廃水処理設備９０と異なり、
陰極側流入管路７４の途中に設けられた沈殿池９３に代
えて、電極反応槽６４の陰極室７２に接続された流出管
路７８の途中に沈殿池１０１が設けられている。また、
沈殿池１０１には、返送用管路１０２が接続されてい
る。Next, a wastewater treatment method according to a sixth embodiment of the present invention will be described with reference to FIG. 6 that are the same as those shown in FIGS. 4 and 5
Except where specifically described, the same members as those described in the fourth and fifth embodiments are shown. The wastewater treatment equipment 100 shown in FIG. 6 is different from the wastewater treatment equipment 90 of the fifth embodiment.
Instead of the sedimentation basin 93 provided in the middle of the cathode-side inflow line 74, a sedimentation basin 101 is provided in the middle of an outflow line 78 connected to the cathode chamber 72 of the electrode reaction tank 64. Also,
A return pipe 102 is connected to the settling basin 101.

【００６８】この廃水処理設備１００を用いた第６実施
形態に係る廃水処理方法では、生物反応槽６１の嫌気部
６３の後段部６３ａから抜き取った２次処理水および活
性汚泥の混合物を、陰極側流入管路７４を介して、電極
反応槽６４の陰極室７２に導入し、電気分解処理が施さ
れた後の混合物を沈殿池１０１に導入する。沈殿池１０
１において混合物中の活性汚泥を沈殿分離し、搬送用管
路９２および１０２を介して好気部６２へ送り返して再
利用に供している。一方、活性汚泥が分離された、電極
反応槽６４で処理された処理水を、流出管路７８および
９５を経て、最終処理水８１として放出している。この
ように、電極反応槽６４の陰極室７２内には微生物が存
在している。このため、陰極６６自体に微生物を固定化
する必要がない利点がある。In the wastewater treatment method according to the sixth embodiment using the wastewater treatment equipment 100, the mixture of the secondary treated water and the activated sludge extracted from the rear part 63a of the anaerobic part 63 of the biological reaction tank 61 is supplied to the cathode side. The mixture after the electrolytic treatment is introduced into the cathode chamber 72 of the electrode reaction tank 64 via the inflow pipe 74, and is introduced into the sedimentation tank 101. Settling pond 10
In 1, the activated sludge in the mixture is settled and separated, sent back to the aerobic section 62 through the conveying pipes 92 and 102, and reused. On the other hand, the treated water from which the activated sludge has been separated and which has been treated in the electrode reaction tank 64 is discharged as final treated water 81 via the outflow pipes 78 and 95. Thus, microorganisms are present in the cathode chamber 72 of the electrode reaction tank 64. Therefore, there is an advantage that it is not necessary to immobilize microorganisms on the cathode 66 itself.

【００６９】なお、第５実施形態および第６実施形態の
廃水処理方法において、電極反応槽６４で処理された処
理水を沈殿池７６に導入しても良い。また、第４実施形
態ないし第６実施形態の廃水処理方法において、生物反
応槽６１の嫌気部６３の後段に好気条件の再曝気槽を設
けて、３次処理水および活性汚泥の混合物を導入してさ
らに処理しても良い。In the wastewater treatment methods of the fifth and sixth embodiments, the treated water treated in the electrode reaction tank 64 may be introduced into the settling basin 76. In the wastewater treatment methods of the fourth to sixth embodiments, a re-aeration tank under aerobic conditions is provided downstream of the anaerobic section 63 of the biological reaction tank 61 to introduce a mixture of tertiary treated water and activated sludge. And may be further processed.

【００７０】以下、生物反応槽に硝化液循環法を適用し
た本発明の廃水処理方法の実施形態について説明する。
図７は、本発明の第７実施形態に係る廃水処理方法に用
いられる廃水処理設備１１０を示す概略図である。図中
１１１は硝化液循環法を適用した生物反応槽である。生
物反応槽１１１は、前段の嫌気部１１２および後段の好
気部１１３を具備する。Hereinafter, an embodiment of the wastewater treatment method of the present invention in which a nitrification liquid circulation method is applied to a biological reaction tank will be described.
FIG. 7 is a schematic diagram showing a wastewater treatment facility 110 used in the wastewater treatment method according to the seventh embodiment of the present invention. In the figure, reference numeral 111 denotes a biological reaction tank to which the nitrification liquid circulation method is applied. The biological reaction tank 111 includes an anaerobic section 112 at the front and an aerobic section 113 at the rear.

【００７１】図７中１１４は、電極反応槽である。電極
反応槽１１４の内部には、一対の陽極１１５および陰極
１１６が互いに対向して配置されている。陽極１１５お
よび陰極１１６は、それぞれ配線１１７、１１８を介し
て電源１１９の陽極側および陰極側にそれぞれ接続され
ている。In FIG. 7, reference numeral 114 denotes an electrode reaction tank. Inside the electrode reaction tank 114, a pair of anode 115 and cathode 116 are arranged to face each other. The anode 115 and the cathode 116 are connected to the anode side and the cathode side of the power supply 119 via wirings 117 and 118, respectively.

【００７２】電極反応槽１１４内は、電気を通すが水分
子、固形物、アンモニア態窒素およびＮＯｘ−Ｎを実質
的に透過しない材質からなる電性隔膜１２０により、陽
極室１２１および陰極室１２２に分割されている。The inside of the electrode reaction tank 114 is connected to the anode chamber 121 and the cathode chamber 122 by an electroconductive diaphragm 120 made of a material that conducts electricity but does not substantially transmit water molecules, solid matter, ammonia nitrogen and NOx-N. Has been split.

【００７３】生物反応槽１１１の好気部１１３の前段部
には、陽極側流入管路１２３が接続されている。この陽
極側流入管路１２３の他端部は、電極反応槽１１４の陽
極室１２１に接続されている。An anode-side inflow pipe 123 is connected to a front part of the aerobic part 113 of the biological reaction tank 111. The other end of the anode-side inflow pipe 123 is connected to the anode chamber 121 of the electrode reaction tank 114.

【００７４】生物反応槽１１１の好気部１１３の後段部
１１３ｂには、陰極側流入管路１２４が接続されてい
る。この陰極側流入管路１２４の他端部は、電極反応槽
１１４の陰極室１２２に接続されている。また、生物反
応槽１１１の好気部１１３の後段部１１３ｂには、処理
水および活性汚泥の混合物の一部を嫌気部１１１２へ送
り返し、循環させるための循環用管路１２５が接続され
ている。A cathode-side inflow pipe 124 is connected to a rear part 113 b of the aerobic part 113 of the biological reaction tank 111. The other end of the cathode-side inflow conduit 124 is connected to the cathode chamber 122 of the electrode reaction tank 114. In addition, a circulation pipeline 125 for sending a part of the mixture of the treated water and the activated sludge back to the anaerobic section 1112 and circulating it is connected to a rear section 113b of the aerobic section 113 of the biological reaction tank 111.

【００７５】電極反応槽１１４の陽極室１２１および陰
極室１２２の後段部には、それぞれ、流出管路１２６、
１２７がそれぞれ接続されている。これらの流出管路１
２６、１２７は一つの流出管路１２８に合流している。
この流出管路１２８の後流側端部は沈殿池１２９まで達
している。この沈殿池１２９には、後述のように沈殿し
た活性汚泥を、生物反応槽１１１の嫌気部１１２に戻す
ための返送用管路１３０が設けられている。At the rear of the anode chamber 121 and the cathode chamber 122 of the electrode reaction tank 114, an outflow pipe 126,
127 are respectively connected. These outflow lines 1
26 and 127 merge into one outlet line 128.
The downstream end of the outflow pipe 128 reaches the sedimentation tank 129. The settling tank 129 is provided with a return pipe 130 for returning the activated sludge settled as described later to the anaerobic section 112 of the biological reaction tank 111.

【００７６】上述のような構成からなる廃水処理設備１
１０を用いて、次の通り廃水処理が行われる。まず、流
入水１を、生物反応槽１１１の嫌気部１１２を導入す
る。嫌気部１１２では、新しい流入水１と、後述のよう
に好気部１１３から戻された処理水に対して、嫌気条件
下で微生物によりＮＯｘ−Ｎの還元が行われる。この嫌
気部１１２で処理を受けた廃水（以下、１次処理水とい
う）は、後段の好気部１１３に送られる。The wastewater treatment equipment 1 having the above configuration
Using 10, wastewater treatment is performed as follows. First, the influent water 1 is introduced into the anaerobic part 112 of the biological reaction tank 111. In the anaerobic section 112, NOx-N is reduced by microorganisms under anaerobic conditions with respect to the fresh inflow water 1 and the treated water returned from the aerobic section 113 as described later. The wastewater treated in the anaerobic section 112 (hereinafter, referred to as primary treated water) is sent to the aerobic section 113 at the subsequent stage.

【００７７】好気部１１３の前段部１１３ａでは、嫌気
部１１２からの一次処理水に含まれる炭素質の汚濁物質
が除去されているが、アンモニア態窒素の還元は起こっ
ていない。この段階の廃水（以下、２次処理水という）
および活性汚泥の混合物を、陽極側流入管路１２３を介
して、電極反応槽１１４の陽極室１２１に導入する。In the former part 113a of the aerobic part 113, carbonaceous pollutants contained in the primary treated water from the anaerobic part 112 have been removed, but no reduction of ammonia nitrogen has occurred. Wastewater at this stage (hereinafter referred to as secondary treated water)
The mixture of the activated sludge and the activated sludge is introduced into the anode chamber 121 of the electrode reaction tank 114 via the anode-side inflow pipe 123.

【００７８】好気部１１３の後段部１１３ｂでは、残り
の２次処理水中のアンモニア態窒素が、微生物により好
気条件下で酸化され、窒素ガスになる。このように後段
部１１３ｂで処理された廃水（以下、３次処理水とい
う）および活性汚泥の混合物の一部を、陰極側流入管路
１２４を介して、電極反応槽１１４の陰極室１２２に導
入する。また、３次処理水および活性汚泥の混合物の一
部を、循環用管路１２５を介して生物反応槽１１１の嫌
気部１１２に送り返す。In the rear part 113b of the aerobic part 113, the ammonia nitrogen in the remaining secondary treatment water is oxidized by a microorganism under aerobic conditions to become nitrogen gas. A part of the mixture of the wastewater (hereinafter, referred to as tertiary treated water) and the activated sludge thus treated in the rear stage 113b is introduced into the cathode chamber 122 of the electrode reaction tank 114 via the cathode-side inflow pipe 124. I do. Further, a part of the mixture of the tertiary treated water and the activated sludge is sent back to the anaerobic part 112 of the biological reaction tank 111 via the circulation pipe 125.

【００７９】一方、電極反応槽１１４においては、陽極
１１５および陰極１１６の間に電源１１９からそれぞれ
配線１１８、１１９を介して直流電圧を印加し、生物反
応槽１１１から導入された２次処理水および３次処理水
に電流を流して電気分解を行う。電極反応槽１１４での
電気分解により、陰極１１６側では、上記式（１）およ
び（２）に示す反応が進行し、３次処理水中のＮＯｘ−
Ｎが窒素ガスに還元される。一方、陽極１１５側では、
上記式（３）に示す反応が進行し、２次処理水中のアン
モニア態窒素が窒素ガスに酸化される。On the other hand, in the electrode reaction tank 114, a DC voltage is applied between the anode 115 and the cathode 116 from the power supply 119 via the wirings 118 and 119, respectively, and the secondary treated water introduced from the biological reaction tank 111 and Electrolysis is performed by passing an electric current through the tertiary treated water. By the electrolysis in the electrode reaction tank 114, the reactions shown in the above formulas (1) and (2) proceed on the cathode 116 side, and NOx-
N is reduced to nitrogen gas. On the other hand, on the anode 115 side,
The reaction represented by the above formula (3) proceeds, and ammonia nitrogen in the secondary treatment water is oxidized to nitrogen gas.

【００８０】このように電極反応槽１１４の陽極室１２
１および陰極室１２２で処理された廃水（以下、４次処
理水という）および活性汚泥の混合物を、流出管路１２
６、１２７および流出管路１２８を順次介して沈殿池１
２９に導入する。沈殿池１２９では、混合物中の活性汚
泥を沈殿させる。沈殿した活性汚泥を、返送用管路１３
０を介して生物反応槽１１１の嫌気部１１２に戻して再
利用する。一方、沈殿池１２９で活性汚泥が沈殿した後
の上澄み水は、最終処理水１３１として放流される。通
常、最終処理水１３１は、滅菌処理を施された後に放流
される。As described above, the anode chamber 12 of the electrode reaction tank 114
1 and the mixture of the activated sludge and the wastewater treated in the cathode chamber 122 (hereinafter referred to as quaternary treated water).
6, 127 and the outflow line 128 in order,
29. In the settling tank 129, the activated sludge in the mixture is settled. The precipitated activated sludge is returned to the return line 13.
The wastewater is returned to the anaerobic part 112 of the biological reaction tank 111 via the slag 0 and reused. On the other hand, the supernatant water after the activated sludge has settled in the sedimentation tank 129 is discharged as the final treated water 131. Usually, the final treated water 131 is discharged after being subjected to a sterilization treatment.

【００８１】上記第７実施形態に係る廃水処理方法によ
れば、生物反応槽１１１の好気部の１１３の前段部１１
３ａから、炭素質の汚泥物質がおおむね除去され、アン
モニア態窒素の酸化がほとんど起こっていない段階の２
次処理水および活性汚泥の混合物を、陽極側流入管路１
２３を介して、電気反応槽１１４の陽極室１２１に導入
する。これにより、生物反応槽１１４への水量負荷が軽
減されるため、生物反応槽１１４での廃水の滞留時間が
長くなる。この結果、生物反応槽１１１の容積が従来の
ように小さくても、生物学的な廃水処理を十分に行うこ
とができる。According to the wastewater treatment method of the seventh embodiment, the front part 11 of the aerobic part 113 of the biological reaction tank 111
3a, where the carbonaceous sludge material is largely removed and the oxidation of ammonia nitrogen hardly occurs.
The mixture of the next treatment water and the activated sludge is supplied to the anode side inflow line 1
Through 23, it is introduced into the anode chamber 121 of the electric reaction tank 114. Thereby, the amount of water load on the biological reaction tank 114 is reduced, and the residence time of the wastewater in the biological reaction tank 114 is lengthened. As a result, even if the volume of the biological reaction tank 111 is small as in the related art, biological wastewater treatment can be sufficiently performed.

【００８２】一方、好気部１１３の前段部１１３ａおよ
び後段部１１３ｂから抜き取られた２次処理水および３
次処理水に対しては、第１実施形態と同様に、それぞ
れ、電極反応槽１１４の陽極室１２１および陰極室１２
２で電気分解による処理が施される。この電気分解で
は、第１実施形態に関して説明した通り、上記式
（１）、（２）および（３）の反応が同時に進行する。
このため、電流が陽極１１５と陰極１１６の両方で利用
されるので、従来の方法と比較して大幅に処理エネルギ
ーを削減できる。On the other hand, the secondary treated water extracted from the front section 113a and the rear section 113b of the aerobic section 113 and
For the next treated water, as in the first embodiment, the anode chamber 121 and the cathode chamber 12 of the electrode reaction tank 114 are respectively provided.
In step 2, an electrolysis treatment is performed. In this electrolysis, as described in the first embodiment, the reactions of the above formulas (1), (2) and (3) proceed simultaneously.
For this reason, since the current is used for both the anode 115 and the cathode 116, the processing energy can be significantly reduced as compared with the conventional method.

【００８３】以上説明したように、この第７実施形態の
廃水処理方法によれば、第１実施形態で説明した活性汚
泥法の場合と同様に、硝化液循環法を適用した生物反応
槽１１１の嫌気部１１２および好気部１１３において十
分な酸化および還元反応に必要な容積を小さくできるた
め、従来の廃水処理方法と比較して、同等またはより小
さい生物反応槽を用いて、廃水中の汚濁物質を十分に除
去できる。また、電極反応槽１１４での電気分解の消費
エネルギーも削減できる。As described above, according to the wastewater treatment method of the seventh embodiment, similar to the case of the activated sludge method described in the first embodiment, the biological reaction tank 111 to which the nitrification liquid circulation method is applied is used. Since the volume required for a sufficient oxidation and reduction reaction in the anaerobic section 112 and the aerobic section 113 can be reduced, the pollutants in the wastewater can be reduced by using a biological reaction tank equivalent to or smaller than the conventional wastewater treatment method. Can be sufficiently removed. Further, the energy consumption of the electrolysis in the electrode reaction tank 114 can be reduced.

【００８４】さらに、生物反応槽１１１の好気部１１３
から流出するＮＯｘ−Ｎを豊富に含有する３次処理水
は、電極反応槽１１１で処理するため、従来の硝化液循
環方途は異なり、最終的に放出される最終処理水中にＮ
Ｏｘ−Ｎが残留するおそれが少ない。Further, the aerobic section 113 of the biological reaction tank 111
Since the tertiary treated water containing NOx-N abundantly flowing out of the tank is treated in the electrode reaction tank 111, the conventional nitrification liquid circulation method is different, and the final treated water discharged finally has N
Ox-N is less likely to remain.

【００８５】上記第８実施形態では、生物反応槽１１１
の好気部１１３の前段部１１３ａから２次処理水および
活性汚泥の混合物の一部を抜き取って、電極反応槽１１
４の陽極室１２１に導入しているが、生物反応槽１１１
の嫌気部１１２の後段部１１２ｂから１次処理水および
活性汚泥の混合物の一部を抜き取っても良い。In the eighth embodiment, the biological reaction tank 111
A part of the mixture of the secondary treatment water and the activated sludge is withdrawn from the front part 113a of the aerobic part 113 of the
4 is introduced into the anode chamber 121,
A part of the mixture of the primary treatment water and the activated sludge may be extracted from the rear part 112b of the anaerobic part 112.

【００８６】図８は、本発明の第８実施形態に係る廃水
処理方法に用いられる廃水処理施設を示す概略図であ
る。図８中に示す符号のうち、図７に示す符号と同じも
のは、特に説明する場合を除き、第７実施形態に関して
説明した部材と同じものを示す。FIG. 8 is a schematic diagram showing a wastewater treatment facility used in the wastewater treatment method according to the eighth embodiment of the present invention. 8, the same reference numerals as those shown in FIG. 7 indicate the same members as those described with respect to the seventh embodiment, unless otherwise specified.

【００８７】図８に示す廃水処理施設１４０は、次の点
で図７に示す廃水処理設備１１０と相違する。第１に、
生物反応槽１１１の好気部１１３の前段部１１３ａから
２次処理水および活性汚泥の混合物を抜き取るための陽
極側流入管路１２３の途中に、沈殿池１４１が設けられ
ている。また、沈殿池１４１には、沈殿した活性汚泥を
嫌気部１１２に送り返すための返送用管路１４２が設け
られている。The wastewater treatment facility 140 shown in FIG. 8 differs from the wastewater treatment facility 110 shown in FIG. 7 in the following points. First,
A sedimentation basin 141 is provided in the middle of the anode-side inflow pipe 123 for extracting the mixture of the secondary treatment water and the activated sludge from the front part 113a of the aerobic part 113 of the biological reaction tank 111. The settling basin 141 is provided with a return pipe 142 for returning the settled activated sludge to the anaerobic section 112.

【００８８】第２に、生物反応槽１１１の好気部１１３
の後段部１１３ａから３次処理水および活性汚泥の混合
物を抜き取るための陰極側流入管路１２４の途中には、
沈殿池１４３が設けられている。この沈殿池１４３に
は、返送用管路１４４が接続され、この返送用管路１４
４は、沈殿池１４１に接続された返送用管路１４２に合
流している。Second, the aerobic part 113 of the biological reaction tank 111
In the middle of the cathode-side inflow conduit 124 for extracting the mixture of the tertiary treated water and the activated sludge from the rear stage 113a,
A settling basin 143 is provided. A return line 144 is connected to the sedimentation tank 143.
4 joins a return pipe 142 connected to the sedimentation basin 141.

【００８９】第３に、電極反応槽６４の陽極室７１およ
び陰極室７２で処理された４次処理水は、流出管路１２
６、１２７を経て、沈殿池を介さずに最終処理水１４５
として放出するようになっている。Third, the quaternary treated water treated in the anode chamber 71 and the cathode chamber 72 of the electrode reaction tank 64 is supplied to the outlet pipe 12.
6, 127, the final treated water 145 without passing through the sedimentation basin.
It is designed to emit as.

【００９０】上述の廃水処理設備１４０を用いた第８実
施形態に係る廃水処理方法では、生物処理槽１１１の好
気部１１３の前段部１１３ａから抜き取られた２次処理
水および活性汚泥の混合物を、陽極側流入管路１２３の
途中に設けられた沈殿池１４１に導入し、この沈殿池１
４１において混合物中の活性汚泥を沈殿分離する。沈殿
した活性汚泥は、搬送用管路１４２を介して嫌気部１１
２の前段部１１２ａに送り返して再利用に供する。一
方、沈殿池１４１で活性汚泥が分離された２次処理水
を、陽極側流入管路１２３を介して、電極反応槽１１４
の陽極室１２１に導入する。In the wastewater treatment method according to the eighth embodiment using the wastewater treatment equipment 140 described above, the mixture of the secondary treated water and the activated sludge extracted from the front part 113a of the aerobic part 113 of the biological treatment tank 111 is used. Is introduced into a sedimentation basin 141 provided in the middle of the anode-side inflow pipe 123, and the sedimentation basin 1
At 41, the activated sludge in the mixture is separated by settling. The settled activated sludge is transferred to the anaerobic section 11 via the conveying pipe 142.
It is sent back to the front part 112a for reuse. On the other hand, the secondary treated water from which activated sludge has been separated in the sedimentation tank 141 is supplied to the electrode reaction tank 114 via the anode-side inflow pipe 123.
Into the anode chamber 121.

【００９１】同様に、好気部１１３の後段部１１３ｂか
ら抜き取られた３次処理水および活性汚泥の混合物の一
部を、陰極側流入管路１２４の途中に設けられた沈殿池
１４３に導入し、この沈殿池１４３において混合物中の
活性汚泥を沈殿分離する。沈殿した活性汚泥は、搬送用
管路１４２および１４３を介して嫌気部１１２の前段部
１１２ａに送り返して再利用に供する。一方、沈殿池１
４３で活性汚泥が分離された３次処理水を、陰極側流入
管路１２４を介して電極反応槽１１４の陰極室１２２に
導入する。Similarly, a part of the mixture of the tertiary treated water and the activated sludge extracted from the rear part 113b of the aerobic part 113 is introduced into the sedimentation tank 143 provided in the middle of the cathode side inflow pipe 124. In this sedimentation tank 143, the activated sludge in the mixture is settled and separated. The precipitated activated sludge is sent back to the front part 112a of the anaerobic part 112 through the conduits 142 and 143 for reuse. On the other hand, sedimentation basin 1
The tertiary treated water from which the activated sludge has been separated at 43 is introduced into the cathode chamber 122 of the electrode reaction tank 114 via the cathode-side inflow pipe 124.

【００９２】このように電極反応槽１１４の陽極室１２
１および陰極室１２２には、活性汚泥を含まない２次お
よび３次処理水を導入するため、電極反応槽１１４へ微
生物は流入しない。このため、微生物の活性は、大電流
を陽極１１５および陰極１１６の間に流すと低下するこ
とがあるが、この第８実施形態では、陰極１１６とし
て、ＮＯｘ−Ｎを窒素ガスに還元する能力を有する電極
を用いた場合には、電極反応槽１１４の中には微生物は
関与しないので、大電流を流しても問題ない。この結
果、第８実施形態に係る廃水処理方法は、生物反応槽１
１１を小型化できる等の第７実施形態の方法と同様の効
果に加え、陽極１１５および陰極１１６の間に大電流を
流し、電気反応槽１１４の処理能力を増大させることが
できるという効果を奏する。As described above, the anode chamber 12 of the electrode reaction tank 114
Microbes do not flow into the electrode reaction tank 114 because secondary and tertiary treated water not containing activated sludge is introduced into the first and cathode chambers 122. For this reason, the activity of the microorganisms may decrease when a large current flows between the anode 115 and the cathode 116. In the eighth embodiment, the activity of the NOx-N for reducing NOx-N to nitrogen gas is reduced as the cathode 116. In the case of using an electrode having the same, microorganisms do not participate in the electrode reaction tank 114, so that there is no problem even if a large current flows. As a result, the wastewater treatment method according to the eighth embodiment has the biological reaction tank 1
In addition to the same effect as the method of the seventh embodiment, such as the size of the electrode 11 can be reduced, a large current can flow between the anode 115 and the cathode 116 to increase the processing capacity of the electric reaction tank 114. .

【００９３】次に、図９を参照して本発明の第９実施形
態にかかる廃水処理方法について説明する。図９中に示
す符号のうち、図７および８に示す符号と同じものは、
特に説明する場合を除き、第７、８実施形態に関して説
明した部材と同じものを示す。図９に示す廃水処理設備
１５０は、第５実施形態の廃水処理設備１４０と異な
り、陰極側流入管路１２４の途中に設けられた沈殿池１
４３に代えて、電極反応槽１１４の陰極室１２２に接続
された流出管路１２８の途中に沈殿池１５１が設けられ
ている。また、沈殿池１５１には、返送用管路１５２が
接続されている。Next, a wastewater treatment method according to a ninth embodiment of the present invention will be described with reference to FIG. 9 that are the same as those shown in FIGS. 7 and 8
Except where specifically described, the same members as those described in regard to the seventh and eighth embodiments are shown. The wastewater treatment equipment 150 shown in FIG. 9 differs from the wastewater treatment equipment 140 of the fifth embodiment in that the sedimentation basin 1 provided in the middle of the cathode-side inflow pipe 124 is provided.
Instead of 43, a sedimentation basin 151 is provided in the middle of an outflow pipe 128 connected to the cathode chamber 122 of the electrode reaction tank 114. In addition, a return pipe 152 is connected to the sedimentation tank 151.

【００９４】この廃水処理設備１５０を用いた第９実施
形態に係る廃水処理方法では、生物反応槽１１１の好気
部１１３の後段部１１３ａから抜き取った３次処理水お
よび活性汚泥の混合物を、陰極側流入管路１２４を介し
て、電極反応槽１１４の陰極室１２２に導入し、電気分
解処理が施された後の混合物を沈殿池１５１に導入す
る。沈殿池１５１において混合物中の活性汚泥を沈殿分
離し、搬送用管路１４２および１５２を介して嫌気部１
１２へ送り返して再利用に供している。一方、活性汚泥
が分離された上澄み液を、流出管路１２８を経て、最終
処理水１３１として放出している。このように、電極反
応槽１１４の陰極室１２２内には微生物が存在してい
る。このため、陰極１１６自体に微生物を固定化する必
要がない利点がある。In the wastewater treatment method according to the ninth embodiment using the wastewater treatment equipment 150, the mixture of the tertiary treated water and the activated sludge extracted from the rear part 113a of the aerobic part 113 of the biological reaction tank 111 is used as a cathode. The mixture after the electrolysis treatment is introduced into the cathode chamber 122 of the electrode reaction tank 114 via the side inflow conduit 124, and is introduced into the sedimentation tank 151. Activated sludge in the mixture is settled and separated in the sedimentation tank 151, and the anaerobic part 1 is separated through the conveying pipes 142 and 152.
It is sent back to 12 for reuse. On the other hand, the supernatant liquid from which the activated sludge has been separated is discharged as final treated water 131 via an outflow pipe 128. Thus, microorganisms are present in the cathode chamber 122 of the electrode reaction tank 114. For this reason, there is an advantage that it is not necessary to immobilize microorganisms on the cathode 116 itself.

【００９５】なお、第６実施形態ないし第９実施形態の
廃水処理方法において、生物反応槽１１１または６１の
嫌気部１１２または６２の前段に嫌気槽を別途設け、流
入水１と沈殿池１４１、１５１、または、９１、１０
１、７６から返送された活性汚泥を嫌気槽に投入し、こ
の嫌気槽での処理された処理水および活性汚泥の混合物
を嫌気部１１２または６２に投入しても良い。この場
合、廃水中のリンの除去も可能になるという利点があ
る。In the wastewater treatment methods of the sixth to ninth embodiments, an anaerobic tank is separately provided in front of the anaerobic section 112 or 62 of the biological reaction tank 111 or 61, and the inflow water 1 and the sedimentation basins 141 and 151 are provided. , Or 91, 10
The activated sludge returned from 1 and 76 may be charged into an anaerobic tank, and a mixture of the treated water and activated sludge treated in the anaerobic tank may be charged into the anaerobic section 112 or 62. In this case, there is an advantage that phosphorus in wastewater can be removed.

【００９６】上述の第１、第３、第４、第６、第７およ
び第９実施形態では、陰極室内に微生物が存在するた
め、陰極自体に微生物を固定化する必要はない。また、
第１および第９実施形態では、陰極としてＮＯｘ−Ｎを
電気化学的に還元して窒素ガスとする能力を有する電極
を用いることもできる。In the first, third, fourth, sixth, seventh, and ninth embodiments, since microorganisms are present in the cathode chamber, there is no need to immobilize microorganisms on the cathode itself. Also,
In the first and ninth embodiments, an electrode having the ability to electrochemically reduce NOx-N into nitrogen gas can be used as the cathode.

【００９７】前述したように、本発明では、陽極には、
アンモニア態窒素を窒素ガスに酸化できる能力を有する
電極の他に、塩素ガスを発生する電極を用いることもで
きる。ただし、この場合で、廃水の塩素イオン濃度が小
さい場合には、廃水に塩化物を添加して塩素イオン濃度
を上げることで、反応効率を上げることができる。ま
た、第１、第４および第７実施形態では、塩素ガスが微
生物の活性を阻害する場合があるので、これらの実施形
態では、塩素ガスを発生する電極の利用には注意が必要
である。As described above, in the present invention, the anode includes:
In addition to an electrode capable of oxidizing ammonia nitrogen to nitrogen gas, an electrode that generates chlorine gas can also be used. However, in this case, when the chloride ion concentration of the wastewater is low, the reaction efficiency can be increased by adding chloride to the wastewater to increase the chloride ion concentration. Also, in the first, fourth and seventh embodiments, since chlorine gas may inhibit the activity of microorganisms, care must be taken in using an electrode that generates chlorine gas in these embodiments.

【００９８】第１〜第９実施形態に共通する事項とし
て、次の事項が挙げられる。第１に、廃水と電極との接
触効率を高めることは、反応効率を高く保つ上で有効で
あり、反応槽内を撹拌することは効果がある。さらに、
電極反応槽の陽極室は酸化雰囲気であるため、陽極室内
に空気のような酸素含有ガスを吹き込むことによって、
撹拌を行うことができる。一方、陰極室内をガス撹拌す
る場合には、陰極室内は還元雰囲気であり、陰極室内に
は酸素を含有しないガスを吹き込む必要がある。The following items are common to the first to ninth embodiments. First, increasing the contact efficiency between the wastewater and the electrode is effective in keeping the reaction efficiency high, and stirring the inside of the reaction tank is effective. further,
Since the anode chamber of the electrode reaction tank is in an oxidizing atmosphere, by blowing an oxygen-containing gas such as air into the anode chamber,
Stirring can be performed. On the other hand, when gas is stirred in the cathode chamber, the cathode chamber is in a reducing atmosphere, and it is necessary to blow a gas containing no oxygen into the cathode chamber.

【００９９】第２に、廃水中の窒素成分の濃度が低い場
合には、電極反応槽を陽極と陰極を隔てる導電性隔膜
は、必ずしも必要ではない。第３に、電極反応槽での消
費電力は電圧と電流と通電時間の積に比例するが、反応
量は電流と通電時間の積に比例する。よって、一定の反
応量を一定の時間で得ようとした場合、所定の電流を流
す必要があり、電流は下げることができないので、消費
電力を減ずるためには電圧を下げれば良いことになる。
ところで、電圧は電流と抵抗の積であり、前述のように
電流値は一定であるとすれば、電圧を下げるためには抵
抗を下げることとなる。ここで、本発明における電極間
の電気抵抗は、反応内水の電気伝導度、電極間距離およ
び電極面積の関数であり、伝導度が一定であれば電極間
距離は小さいほど、電極面積は大きいほど電極間の電気
抵抗は小さいこととなる。このことから、処理エネルギ
ーの低減のためには、電極総面積を大とし電極を近接さ
せて設置することが望ましい。Second, when the concentration of the nitrogen component in the wastewater is low, a conductive diaphragm for separating the anode and the cathode from the electrode reaction tank is not always necessary. Third, the power consumption in the electrode reaction vessel is proportional to the product of the voltage, the current, and the energizing time, while the amount of reaction is proportional to the product of the current, the energizing time. Therefore, when a certain amount of reaction is to be obtained in a certain period of time, it is necessary to flow a predetermined current, and the current cannot be reduced. Therefore, in order to reduce power consumption, the voltage may be reduced.
By the way, the voltage is the product of the current and the resistance, and if the current value is constant as described above, the resistance must be reduced in order to lower the voltage. Here, the electric resistance between the electrodes in the present invention is a function of the electric conductivity of the internal reaction water, the distance between the electrodes, and the electrode area. If the conductivity is constant, the smaller the distance between the electrodes, the larger the electrode area. The smaller the electrical resistance between the electrodes, the lower the resistance. For this reason, in order to reduce the processing energy, it is desirable to increase the total area of the electrodes and arrange the electrodes close to each other.

【０１００】第４に、現状で開発されている電極での電
力効率を考えると、１０ファラデーの電流で１モルのＮ
Ｏｘ−Ｎの処理と同時に０．６７モルのアンモニア態窒
素の処理が可能であるため、ＮＯｘ−Ｎ：アンモニア態
窒素の比率が１：０．６７となるように流量を設定する
ことが効果的である。ただし、最適比率は、流入水の性
状や、電極の効率によって異なる。Fourth, considering the power efficiency of the currently developed electrode, one mole of N at a current of 10 Faraday is considered.
Since it is possible to treat 0.67 mol of ammonia nitrogen simultaneously with the treatment of Ox-N, it is effective to set the flow rate so that the ratio of NOx-N: ammonium nitrogen is 1: 0.67. It is. However, the optimum ratio varies depending on the properties of the inflow water and the efficiency of the electrode.

【０１０１】第５に、最終処理水に含まれる固形分を、
膜分離、ろ過、遠心分離などの固液気分離を行うことに
よってさらに清澄な処理水とすることができる。特に、
第２、第７および第８実施形態では、電極反応槽から流
出した処理水が最終処理水として放出されるが、陰極と
して微生物を固定化した電極を用いた場合には処理水に
電極から剥離した微生物が混入することがあるため、要
求処理水質によっては、このような固液分離処理が必要
となる場合がある。Fifth, the solid content contained in the final treated water is
By performing solid-liquid gas separation such as membrane separation, filtration, and centrifugation, clearer treated water can be obtained. Especially,
In the second, seventh, and eighth embodiments, the treated water flowing out of the electrode reaction tank is released as the final treated water. However, when an electrode on which microorganisms are immobilized is used as the cathode, the treated water separates from the electrode. Such a solid-liquid separation treatment may be required depending on the required treatment water quality because the microorganisms may be mixed.

【０１０２】第６では、流入水の全量をほぼ１００％の
窒素除去率で処理することを目的としれいるが、実際に
はここまでの除去率が求められない場合もある。このよ
うな場合には、電極反応槽への導入水量や電極反応槽の
電流、電圧などの運転条件を制御することで、処理水質
を制御することができる。The sixth purpose may be to treat the entire amount of inflow water with a nitrogen removal rate of almost 100%. However, there may be cases where the removal rate up to this point is not actually obtained. In such a case, the quality of treated water can be controlled by controlling operating conditions such as the amount of water introduced into the electrode reaction tank and the current and voltage of the electrode reaction tank.

【０１０３】第７に、ほぼ１００％の窒素除去率が求め
られない場合には、さらに多様な変更が可能であり、従
って、以下に示す変形例のすべてが本発明の範囲内に含
まれる。すなわち、 ・第１実施形態では生物反応槽１１の後段部１１ｂから
の混合物の一部を沈澱池２６に導入すること、 ・第２実施形態では、沈澱池３２の上澄み液の一部を電
極反応層１２へは導入せず、最終処理水４１に混合して
放出すること、 ・第３実施形態では、生物反応槽１１の後段部１１ｂか
らの混合物の一部を沈澱池４３に導入すること、 ・第７実施形態においては、生物反応槽１１１の好気部
１１３の後段部１１３ａからの混合物の一部を沈澱池１
３１に導入すること、 ・第８実施形態において、沈澱池１４１または１４３か
らの上澄み液の一部を電極反応層１１４へは導入せず、
最終処理水１３１と混合し放出すること、 ・第９実施形態においては、生物反応槽１１１の好気部
１１３の後段部１１３ａからの混合物の一部を沈澱池１
５１に導入すること。Seventh, if a nitrogen removal rate of almost 100% is not required, further various modifications are possible, and all of the following modifications are included in the scope of the present invention. In the first embodiment, a part of the mixture from the rear part 11b of the biological reaction tank 11 is introduced into the precipitation tank 26. In the second embodiment, a part of the supernatant of the precipitation tank 32 is subjected to an electrode reaction. Introducing a part of the mixture from the rear part 11b of the biological reaction tank 11 into the sedimentation basin 43 in the third embodiment, In the seventh embodiment, a part of the mixture from the rear part 113a of the aerobic part 113 of the biological reaction tank 111
In the eighth embodiment, a part of the supernatant from the precipitation tank 141 or 143 is not introduced into the electrode reaction layer 114,
Mixing and discharging with the final treated water 131; in the ninth embodiment, part of the mixture from the rear part 113a of the aerobic part 113 of the biological reaction tank 111 is settled in the sedimentation basin 1
Introduce to 51.

【０１０４】以上のような変形例に係る廃水処理方法
は、生物反応槽で処理された水の一部または全部を電極
反応槽に導入して電気化学的に処理することにより、生
物反応槽の水量負荷を低減することと、電極反応槽での
電気分解で電流を陽極と陰極の両方で利用する２つの工
程を具備することから、本発明の技術的範囲内に含まれ
ることは明らかである。上記の変形例以外にも、これら
の工程を具備する廃水処理方法はすべて本発明の範囲に
含まれる。In the wastewater treatment method according to the above modification, a part or all of the water treated in the biological reaction tank is introduced into the electrode reaction tank and electrochemically treated, whereby the wastewater in the biological reaction tank is treated. It is clear that the method is included in the technical scope of the present invention because it has two steps of reducing the water load and using the current in both the anode and the cathode in the electrolysis in the electrode reaction tank. . In addition to the above-described modified examples, all wastewater treatment methods including these steps are included in the scope of the present invention.

【０１０５】第８に、ＮＯｘ−Ｎの還元剤としては、電
極反応で生成される水素以外に、メタノールなどの種々
の有機物を用いることができるので、電極反応槽の陰極
室へこれらの有機物を添加することも効果がある。ただ
し、導電性隔膜を設けず、電極反応槽を陽極室および陰
極室に分割しない場合には、添加した有機物が陽極で分
解されるため、有機物添加の効果が下がり、かつ、有機
物の分解のために陽極で余分なエネルギーが消費される
ので、有機物の添加は好ましくない。Eighth, since various organic substances such as methanol can be used as the NOx-N reducing agent in addition to hydrogen generated by the electrode reaction, these organic substances are transferred to the cathode chamber of the electrode reaction tank. Addition is also effective. However, when the conductive diaphragm is not provided and the electrode reaction tank is not divided into an anode chamber and a cathode chamber, the added organic substance is decomposed at the anode, so the effect of adding the organic substance is reduced, and the decomposition of the organic substance is performed. However, addition of organic matter is not preferable because extra energy is consumed at the anode.

【０１０６】また、電極反応槽の陰極室へ有機物を添加
する際に、有機物を含有する廃水を添加することもでき
る。ただし、陰極側ではアンモニア態窒素の除去は行わ
れないため、この際に添加する廃水としては、（アンモ
ニア態窒素／有機物）比の小さい廃水を用いることが好
ましい。また、有機物の過剰添加は、処理水への有機物
の流出を招く恐れがあるため好ましくないが、最終処理
水に流出した有機物を別途処理を行うこともできる。When adding an organic substance to the cathode chamber of the electrode reaction tank, waste water containing the organic substance can be added. However, since ammonia nitrogen is not removed on the cathode side, it is preferable to use wastewater with a small (ammonia nitrogen / organic matter) ratio as wastewater added at this time. Further, excessive addition of the organic substance is not preferable because the organic substance may flow into the treated water. However, the organic substance flowing into the final treated water can be separately treated.

【０１０７】[0107]

【発明の効果】以上説明したように、本発明の廃水処理
方法によれば、生物反応槽で生物学的に処理された廃水
の一部を、電極反応槽に導入して電気分解により処理す
ることにより、生物反応槽および電極反応槽での廃水処
理をそれぞれを単独で行った場合と比較して、消費エネ
ルギーを著しく削減できる。また、電極反応槽での処理
量だけ生物反応槽への廃水の量が低減でき、生物反応槽
での廃水の滞留時間が長くなるため、比較的容積が小さ
い生物反応槽においても安定かつ高い窒素除去効果が得
られる。この結果、廃水中のほぼ１００％の窒素を、省
エネルギー的にかつ省スペース的に除去することが可能
である。As described above, according to the wastewater treatment method of the present invention, a part of the wastewater biologically treated in the biological reactor is introduced into the electrode reactor and treated by electrolysis. Thereby, energy consumption can be remarkably reduced as compared with the case where each of the wastewater treatment in the biological reaction tank and the electrode reaction tank is independently performed. In addition, since the amount of wastewater in the biological reaction tank can be reduced by the amount treated in the electrode reaction tank, and the residence time of the wastewater in the biological reaction tank becomes longer, the stable and high nitrogen content can be obtained even in a relatively small-sized biological reaction tank. The removal effect is obtained. As a result, almost 100% of nitrogen in the wastewater can be removed with energy saving and space saving.

【０１０８】[0108]

【発明の効果】以上説明したように、本発明の廃水処理
方法および廃水処理装置によれば、陽極ではアンモニア
態窒素を窒素ガスに酸化するとともに、陰極で、ＮＯｘ
−Ｎを窒素ガスに還元することにより、アンモニア態窒
素およびＮＯｘ−Ｎをそれぞれを単独で行った場合と比
較して、消費エネルギーの大幅に削減することができ
る。As described above, according to the wastewater treatment method and wastewater treatment apparatus of the present invention, the anode oxidizes ammonia nitrogen to nitrogen gas and the cathode oxidizes NOx.
By reducing -N to nitrogen gas, energy consumption can be significantly reduced as compared with the case where ammonia nitrogen and NOx-N are used alone.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の第１実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 1 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a first embodiment of the present invention.

【図２】本発明の第２実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 2 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a second embodiment of the present invention.

【図３】本発明の第３実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 3 is a schematic view showing a wastewater treatment apparatus used in a wastewater treatment method according to a third embodiment of the present invention.

【図４】本発明の第４実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 4 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a fourth embodiment of the present invention.

【図５】本発明の第５実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 5 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a fifth embodiment of the present invention.

【図６】本発明の第６実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 6 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a sixth embodiment of the present invention.

【図７】本発明の第７実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 7 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a seventh embodiment of the present invention.

【図８】本発明の第８実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 8 is a schematic view showing a wastewater treatment apparatus used in a wastewater treatment method according to an eighth embodiment of the present invention.

【図９】本発明の第９実施形態に係る廃水処理方法に用
いられる廃水処理装置を示す概略図。FIG. 9 is a schematic diagram showing a wastewater treatment apparatus used in a wastewater treatment method according to a ninth embodiment of the present invention.

【図１０】従来の廃水処理方法を示す概略図。FIG. 10 is a schematic diagram showing a conventional wastewater treatment method.

【図１１】従来の廃水処理方法を示す概略図。FIG. 11 is a schematic view showing a conventional wastewater treatment method.

【図１２】従来の廃水処理方法を示す概略図。FIG. 12 is a schematic view showing a conventional wastewater treatment method.

【符号の説明】[Explanation of symbols]

１…流入水、１０…廃水処理設備、１１…生物反応層、
１２…電気反応槽、１３…陽極、１４…陰極、１５、１
６…配線、１７…電源、１８…導電性隔膜、１９…陽極
室、２０…陰極室、２１…陽極側流入管路、２２…陰極
側流入管路、２３、２４、２５…流出管路、２６…沈殿
池、２７…返送用管路、２８…最終処理水。1 ... inflow water, 10 ... wastewater treatment equipment, 11 ... biological reaction layer,
12 ... electric reactor, 13 ... anode, 14 ... cathode, 15, 1
6 wiring, 17 power supply, 18 conductive diaphragm, 19 anode chamber, 20 cathode chamber, 21 anode side inflow line, 22 cathode side inflow line, 23, 24, 25 ... outflow line, 26: sedimentation basin, 27: return line, 28: final treated water.

Claims (7)

【特許請求の範囲】[Claims] 【請求項１】 廃水を生物反応槽に導入して前記廃水に
生物処理を施す工程と、 電極反応槽内に陽極としてのアンモニア態窒素を窒素ガ
スに酸化する能力を有する電極または塩素イオンを塩素
ガスに酸化する能力を有する電極と陰極として水を水素
ガスに還元する能力を有する電極または硝酸態窒素およ
び／または亜硝酸態窒素を窒素ガスに還元する能力を有
する電極をそれぞれ配置し、前記生物反応槽で生物処理
を受けた前記廃水を前記電極反応槽に導入し、前記陽極
および前記陰極の間に電圧を印加して前記廃水の電気分
解を行い、前記陽極において前記廃水中のアンモニア態
窒素を窒素ガスに酸化すると共に、前記陰極において前
記廃水中の硝酸態窒素および／または亜硝酸態窒素を窒
素ガスに還元する工程とを具備することを特徴とする廃
水処理方法。1. A step of introducing wastewater into a biological reaction tank and subjecting the wastewater to biological treatment; and an electrode or a chlorine ion capable of oxidizing ammonia nitrogen as an anode into nitrogen gas in an electrode reaction tank. An electrode capable of oxidizing gas and an electrode capable of reducing water to hydrogen gas as a cathode or an electrode capable of reducing nitrate nitrogen and / or nitrite nitrogen to nitrogen gas are disposed, respectively. The wastewater subjected to biological treatment in the reaction tank is introduced into the electrode reaction tank, and a voltage is applied between the anode and the cathode to perform electrolysis of the wastewater. Oxidizing nitrogen into nitrogen gas and reducing nitrate nitrogen and / or nitrite nitrogen in the wastewater at the cathode to nitrogen gas. Waste water treatment how. 【請求項２】 前記電極反応槽内に、電気を通すが廃水
中の水分子、固形物、アンモニア態窒素および硝酸態窒
素および／または亜硝酸態窒素を実質的に透過しない導
電性隔膜を配し、前記電極反応槽を陽極側および陰極側
に隔てる請求項１記載の廃水処理方法。2. A conductive diaphragm, which conducts electricity but substantially does not transmit water molecules, solid matter, ammonia nitrogen and nitrate nitrogen and / or nitrite nitrogen in wastewater, is disposed in the electrode reaction tank. The wastewater treatment method according to claim 1, wherein the electrode reaction tank is separated on the anode side and the cathode side. 【請求項３】 前記陽極側に前記生物処理槽で処理を受
けた前記廃水のうちアンモニア態窒素を含むがその他の
還元性物質を実質的に含まない処理水を導入し、前記陰
極側に前記生物処理槽で処理を受けた前記廃水のうち窒
素成分を硝酸態窒素および／または亜硝酸態窒素の形で
含む処理水を導入する請求項２記載の廃水処理方法。3. A treatment water containing ammonia nitrogen but substantially containing no other reducing substances is introduced into the wastewater treated in the biological treatment tank on the anode side, and the wastewater is treated on the cathode side. The wastewater treatment method according to claim 2, wherein treated water containing a nitrogen component in the form of nitrate nitrogen and / or nitrite nitrogen in the wastewater treated in the biological treatment tank is introduced. 【請求項４】 前記生物処理槽の前段部から取り出した
処理水を前記陽極側に、前記生物処理槽の後段部から取
り出した処理水を前記陰極側にそれぞれ導入する請求項
２記載の廃水処理方法。4. The wastewater treatment according to claim 2, wherein treated water taken out from a front part of the biological treatment tank is introduced into the anode side, and treated water taken out from a rear part of the biological treatment tank is introduced into the cathode side. Method. 【請求項５】 前記生物処理槽が好気部および嫌気部か
らなる請求項１記載の廃水処理方法。5. The wastewater treatment method according to claim 1, wherein the biological treatment tank comprises an aerobic part and an anaerobic part. 【請求項６】 前記電極反応槽内に、電気を通すが廃水
中の水分子、固形物、アンモニア態窒素および硝酸態窒
素および／または亜硝酸態窒素を実質的に透過しない導
電性隔膜を配し、前記電極反応槽を陽極側および陰極側
に隔てる請求項５記載の廃水処理方法。6. A conductive diaphragm, which conducts electricity but does not substantially transmit water molecules, solid matter, ammonia nitrogen and nitrate nitrogen and / or nitrite nitrogen in wastewater, is disposed in the electrode reaction tank. The wastewater treatment method according to claim 5, wherein the electrode reaction tank is separated on the anode side and the cathode side. 【請求項７】 前記生物処理槽の前記好気部から取り出
した処理水を前記電極反応槽の前記陽極側に導入し、前
記生物処理槽の前記嫌気部から取り出した処理水を前記
電極反応槽の前記陰極側に導入する請求項６記載の廃水
処理方法。7. The treated water taken out of the aerobic part of the biological treatment tank is introduced into the anode side of the electrode reaction tank, and the treated water taken out of the anaerobic part of the biological treatment tank is taken out of the electrode reaction tank. The wastewater treatment method according to claim 6, wherein the wastewater is introduced to the cathode side.
JP8243598A 1996-09-13 1996-09-13 Wastewater treatment method Pending JPH1085752A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8243598A JPH1085752A (en) 1996-09-13 1996-09-13 Wastewater treatment method

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Application Number Priority Date Filing Date Title
JP8243598A JPH1085752A (en) 1996-09-13 1996-09-13 Wastewater treatment method

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Publication Number Publication Date
JPH1085752A true JPH1085752A (en) 1998-04-07

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ID=17106203

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Application Number Title Priority Date Filing Date
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999020570A1 (en) * 1997-10-21 1999-04-29 Senju Pharmaceutical Co., Ltd. Composite material comprising biodegradable plastic and fibrous material
WO2002068339A1 (en) * 2001-02-26 2002-09-06 Sanyo Electric Co., Ltd. Method and system for treating nitrogen-containing compound
EP1295853A3 (en) * 2001-09-19 2003-10-01 Sanyo Electric Co. Ltd Method of treating water and apparatus therefor
JP2006239627A (en) * 2005-03-04 2006-09-14 Mitsubishi Heavy Ind Ltd System for treatment of organic waste water containing nitrogen
US7157012B2 (en) 2003-03-26 2007-01-02 Sanyo Electric Co., Ltd. Water treatment device and water treatment method using the same
WO2014203127A1 (en) 2013-06-17 2014-12-24 Chemitec S.R.L. Method and apparatus for controlling a process of biological treatment of wastewater of civil origin
CN109970291A (en) * 2019-04-30 2019-07-05 广东工业大学 A kind of waste water treatment system and its device and wastewater treatment method
CN110759583A (en) * 2019-09-24 2020-02-07 天津禹信环保科技有限公司 Industrial wastewater's cyclic utilization equipment

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999020570A1 (en) * 1997-10-21 1999-04-29 Senju Pharmaceutical Co., Ltd. Composite material comprising biodegradable plastic and fibrous material
WO2002068339A1 (en) * 2001-02-26 2002-09-06 Sanyo Electric Co., Ltd. Method and system for treating nitrogen-containing compound
EP1295853A3 (en) * 2001-09-19 2003-10-01 Sanyo Electric Co. Ltd Method of treating water and apparatus therefor
US6984326B2 (en) 2001-09-19 2006-01-10 Sanyo Electric Co., Ltd. Nitrogen treating method and nitrogen treating system
US7157012B2 (en) 2003-03-26 2007-01-02 Sanyo Electric Co., Ltd. Water treatment device and water treatment method using the same
JP2006239627A (en) * 2005-03-04 2006-09-14 Mitsubishi Heavy Ind Ltd System for treatment of organic waste water containing nitrogen
WO2014203127A1 (en) 2013-06-17 2014-12-24 Chemitec S.R.L. Method and apparatus for controlling a process of biological treatment of wastewater of civil origin
CN109970291A (en) * 2019-04-30 2019-07-05 广东工业大学 A kind of waste water treatment system and its device and wastewater treatment method
CN110759583A (en) * 2019-09-24 2020-02-07 天津禹信环保科技有限公司 Industrial wastewater's cyclic utilization equipment

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