JP3329195B2 - Activated sludge floating control method - Google Patents
Activated sludge floating control methodInfo
- Publication number
- JP3329195B2 JP3329195B2 JP17944796A JP17944796A JP3329195B2 JP 3329195 B2 JP3329195 B2 JP 3329195B2 JP 17944796 A JP17944796 A JP 17944796A JP 17944796 A JP17944796 A JP 17944796A JP 3329195 B2 JP3329195 B2 JP 3329195B2
- Authority
- JP
- Japan
- Prior art keywords
- activated sludge
- sludge
- mercaptobenzimidazole
- control method
- floating
- 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.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Activated Sludge Processes (AREA)
- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は活性汚泥処理系にお
ける硝化−脱窒反応による活性汚泥の浮上を抑制する方
法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the rise of activated sludge by a nitrification-denitrification reaction in an activated sludge treatment system.
【０００２】[0002]
【従来の技術】有機性排水の活性汚泥処理法では、排水
を曝気槽において活性汚泥と混合して曝気し、固液分離
槽において汚泥を分離し、分離液を処理水として排出す
る一方、分離した汚泥の一部を返送汚泥として曝気槽に
返送し、残部を余剰汚泥として排出している。このよう
な活性汚泥処理法ではズーグレア等の有機物分解菌類が
優勢になった活性汚泥により有機物が分解されるが、過
曝気になると硝化菌により硝化が起こり、その後固液分
離槽において脱窒菌の作用により脱窒され、窒素ガスが
発生する。このとき脱窒により発生した窒素ガスが汚泥
に付着して活性汚泥を浮上させ固液分離効率が悪化する
場合がある。2. Description of the Related Art In an activated sludge treatment method for organic wastewater, wastewater is mixed with activated sludge in an aeration tank and aerated, and the sludge is separated in a solid-liquid separation tank, and the separated liquid is discharged as treated water. A part of the sludge is returned to the aeration tank as return sludge, and the remaining part is discharged as surplus sludge. In such an activated sludge treatment method, organic matter is decomposed by activated sludge in which organic matter-decomposing bacteria such as zooglare have become predominant. Denitrification, and nitrogen gas is generated. At this time, the nitrogen gas generated by the denitrification may adhere to the sludge, causing the activated sludge to float and the solid-liquid separation efficiency to deteriorate.
【０００３】すなわち、原水に窒素化合物が多く含まれ
る場合は、曝気槽において過曝気になることにより、活
性汚泥中の硝酸菌、亜硝酸菌により窒素化合物が硝化さ
れて硝酸態窒素が生成する。この硝酸態窒素は固液分離
槽において嫌気条件下で脱窒菌により窒素ガスに変換さ
れる。このとき脱窒反応により発生した窒素ガスが微細
気泡となって活性汚泥に付着し、活性汚泥を浮上させる
（以下、脱窒浮上現象という）。このような脱窒浮上現
象により汚泥が浮上すると、固液分離槽において汚泥が
分離できなくなり、処理水とともに汚泥が流出するた
め、処理水の水質を著しく悪化させる。[0003] That is, when the raw water contains a large amount of nitrogen compounds, the nitrogen compounds are nitrified by the nitric acid bacteria and nitrite bacteria in the activated sludge to generate nitrate nitrogen by overaeration in the aeration tank. This nitrate nitrogen is converted into nitrogen gas by denitrifying bacteria under anaerobic conditions in a solid-liquid separation tank. At this time, the nitrogen gas generated by the denitrification reaction becomes fine bubbles and adheres to the activated sludge, causing the activated sludge to float (hereinafter, referred to as a denitrification flotation phenomenon). If the sludge floats due to the denitrification flotation phenomenon, the sludge cannot be separated in the solid-liquid separation tank, and the sludge flows out together with the treated water, so that the quality of the treated water is significantly deteriorated.
【０００４】従来、このような脱窒浮上現象を抑制する
方法としてチオ尿素またはアリルチオ尿素を曝気槽に添
加する方法が知られている（例えば、特開昭５３−９９
６６２号）。しかし、これらの薬剤は活性汚泥により容
易に分解され、そのうえ活性汚泥に対する吸着性が弱い
ため、薬効が持続しないという問題点がある。また、農
業用に使用される硝化抑制剤も利用できるが、これらの
使用量はチオ尿素などに比べて多くなる。Conventionally, as a method for suppressing such a denitrification flotation phenomenon, a method of adding thiourea or allylthiourea to an aeration tank has been known (for example, Japanese Patent Application Laid-Open No. 53-99).
No. 662). However, these chemicals are easily decomposed by activated sludge, and furthermore, their adsorptivity to activated sludge is weak. In addition, nitrification inhibitors used for agriculture can be used, but the amount of these used is larger than that of thiourea or the like.
【０００５】[0005]
【発明が解決しようとする課題】本発明の目的は、人畜
に対して安全であり、しかも活性汚泥の活性を低下させ
ない薬剤を少量添加して効果的に硝化を抑制し、これに
より脱窒による活性汚泥の浮上を持続的に抑制すること
ができる活性汚泥の浮上抑制方法を提案することであ
る。SUMMARY OF THE INVENTION It is an object of the present invention to effectively suppress nitrification by adding a small amount of an agent which is safe for humans and animals and does not reduce the activity of activated sludge. An object of the present invention is to propose a method for suppressing floating of activated sludge which can continuously suppress the floating of activated sludge.
【０００６】[0006]
【課題を解決するための手段】本発明は、活性汚泥処理
系に２−メルカプトベンゾイミダゾールを添加すること
を特徴とする活性汚泥の浮上抑制方法である。SUMMARY OF THE INVENTION The present invention is a method for suppressing floating of activated sludge, which comprises adding 2-mercaptobenzimidazole to an activated sludge treatment system.
【０００７】本発明において、活性汚泥処理系とは、活
性汚泥を用いて好気性処理を行うあらゆる方法における
処理系を示し、標準活性汚泥処理法のほかに、その変形
および他の処理法との組合せによる処理法における処理
系を含む。ここで処理系とは、上記処理を行うための系
全体を意味し、この処理系の任意の位置に２−メルカプ
トベンゾイミダゾールを添加することにより、活性汚泥
の浮上を抑制することができる。また本発明において、
抑制とは、活性汚泥の浮上の発生を抑制することのほ
か、すでに発生した活性汚泥の浮上の進行および拡大を
抑制することをも意味する。[0007] In the present invention, the activated sludge treatment system refers to a treatment system in any method for performing aerobic treatment using activated sludge. Includes a processing system in a combination processing method. Here, the treatment system means the entire system for performing the above treatment, and by adding 2-mercaptobenzimidazole to an arbitrary position in the treatment system, floating of activated sludge can be suppressed. In the present invention,
The term “suppression” means, in addition to suppressing the occurrence of floating of activated sludge, suppressing the progress and expansion of the activated sludge that has already occurred.
【０００８】本発明で使用する２−メルカプトベンゾイ
ミダゾールは、式（１）The 2-mercaptobenzimidazole used in the present invention has the formula (1)
【化１】 で示される化合物であり、添加量が少量の場合でも活性
汚泥に効率的に作用し、硝化を抑制する。Embedded image And acts efficiently on activated sludge even when the amount of addition is small, and suppresses nitrification.
【０００９】２−メルカプトベンゾイミダゾールは活性
汚泥処理系の任意の場所に添加することができるが、特
に曝気槽に添加するのが好ましい。２−メルカプトベン
ゾイミダゾールは連続して添加することもできるし、１
〜１０日に１回の割合で間欠的に添加することもできる
が、活性汚泥の浮上抑制効果は長時間持続するので、間
欠的な添加方法で十分効果が発揮される。Although 2-mercaptobenzimidazole can be added to any place in the activated sludge treatment system, it is particularly preferable to add 2-mercaptobenzimidazole to an aeration tank. 2-mercaptobenzimidazole can be added continuously,
It can be added intermittently at a rate of once every 10 days, but the floating sludge suppression effect of activated sludge lasts for a long time, so that the intermittent addition method is sufficiently effective.
【００１０】２−メルカプトベンゾイミダゾールの添加
量は添加位置、添加方法等により異なるが、硝化菌の硝
化反応を抑制できる量を添加する。連続添加の場合は流
入原水に対して０．５〜５ｍｇ／ｌとなるように添加す
るのが好ましい。間欠的に添加する場合は、曝気槽内の
混合液に対して０．１〜１０ｍｇ／ｌ、好ましくは０．
５〜５ｍｇ／ｌの濃度となるように一括して添加するの
が好ましい。このような添加は１〜１０日に１回の割合
で間欠的に行うのが好ましい。The amount of 2-mercaptobenzimidazole varies depending on the position and method of addition, but an amount capable of suppressing the nitrification reaction of nitrifying bacteria is added. In the case of continuous addition, it is preferable to add so that it may become 0.5-5 mg / l with respect to inflow raw water. When adding intermittently, 0.1 to 10 mg / l, preferably 0.1 to 10 mg / l, of the mixture in the aeration tank is used.
It is preferable to add them all at once so as to have a concentration of 5 to 5 mg / l. Such addition is preferably performed intermittently once every 1 to 10 days.
【００１１】このようにして２−メルカプトベンゾイミ
ダゾールを添加することにより、活性汚泥中の亜硝酸
菌、硝酸菌による硝化が阻害され、沈殿槽（固液分離
槽）での脱窒による汚泥浮上は抑制される。このとき活
性汚泥中の他の細菌は影響を受けず、有機物に対する分
解活性は維持される。By adding 2-mercaptobenzimidazole in this way, nitrification by nitrites and nitrates in activated sludge is inhibited, and sludge floating due to denitrification in a sedimentation tank (solid-liquid separation tank) is prevented. Is suppressed. At this time, other bacteria in the activated sludge are not affected, and the decomposition activity for organic matter is maintained.
【００１２】また２−メルカプトベンゾイミダゾール
は、次の通り低毒性であり、人畜に対して安全である。 ＬＤ50（mouse oral）：７５０ｍｇ／ｋｇ 皮膚刺激性（rabbit skin）：５００ｍｇ／２４ｈｒ
ｍｉｌｄ 変異原性：なし 魚毒性：１０ｍｇ／ｌでなしFurther, 2-mercaptobenzimidazole has low toxicity as described below and is safe for humans and animals. LD 50 (mouse oral): 750 mg / kg Skin irritation (rabbit skin): 500 mg / 24 hr
mild Mutagenicity: None Fish toxicity: None at 10 mg / l
【００１３】[0013]
【発明の効果】本発明の活性汚泥の浮上抑制方法は、活
性汚泥処理系に２−メルカプトベンゾイミダゾールを添
加するようにしているので、人畜に対して安全であり、
しかも活性汚泥の活性を低下させない薬剤を少量添加し
て効果的に硝化を抑制することができ、これにより脱窒
による活性汚泥の浮上を持続的に抑制することができ
る。According to the method for suppressing floating of activated sludge of the present invention, 2-mercaptobenzimidazole is added to the activated sludge treatment system, so that it is safe for humans and animals.
In addition, nitrification can be effectively suppressed by adding a small amount of an agent that does not decrease the activity of activated sludge, whereby the floating of activated sludge due to denitrification can be continuously suppressed.
【００１４】[0014]
【発明の実施の形態】次に本発明の実施例について説明
する。 実施例１、比較例１〜３Nitrosomonas europaeaの菌体懸濁液（ｐＨ８の３００
ｍＭリン酸緩衝液によりＯ．Ｄ．６６０ｎｍを０．２に
調整）８．５ｍｌ、１０００ｍｇ−Ｎ／ｌのＮＨ4Ｃｌ
溶液０．５ｍｌ（最終濃度５０ｍｇ−Ｎ／ｌ）、表１に
示す薬剤を溶解した溶液１ｍｌを試験管に入れ、３０℃
で２時間振盪培養した。５時間後にアンモニア濃度を測
定した。結果を表１に示す。Next, an embodiment of the present invention will be described. Example 1, Comparative Examples 1 to 3 Cell suspension of Nitrosomonas europaea (300 at pH 8)
O.mM phosphate buffer. D. 8.5 ml, 1000 mg-N / l NH 4 Cl
0.5 ml of the solution (final concentration 50 mg-N / l) and 1 ml of the solution in which the drugs shown in Table 1 were dissolved were placed in a test tube, and the solution was placed at 30 °
For 2 hours with shaking. After 5 hours, the ammonia concentration was measured. Table 1 shows the results.
【００１５】[0015]
【表１】 ＊１ ＡＣＭＰ：２−アミノ−４−クロロ−６−メチルピリミジン[Table 1] * 1 ACMP: 2-amino-4-chloro-6-methylpyrimidine
【００１６】表１の結果から、２−メルカプトベンゾイ
ミダゾールは他の薬剤に比べて少量の添加で硝化を抑制
することができ、しかもその効果が持続することがわか
る。From the results shown in Table 1, it can be seen that 2-mercaptobenzimidazole can suppress nitrification with a small amount of addition as compared with other drugs, and its effect is maintained.
【００１７】実施例２ 活性汚泥（ＭＬＳＳ ２０００ｍｇ／ｌ）を曝気槽容量
５ liter、沈殿槽容量３ literの返送汚泥管を付けた活
性汚泥処理装置に入れて人工排水を通水し、３０℃にお
いて５ liter／分で通気して排水処理した。人工排水は
グルコース１０％、ペプトン１０％、塩化アンモニウム
１０％、リン酸一カリウム１％、リン酸一ナトリウム２
％の組成でｐＨ７．０に調整した。ＴＯＣ負荷は０．５
ｋｇ／ｍ 3・日、返送率は５０％とした。Example 2 Activated sludge (MLSS 2000 mg / l) was supplied to an aeration tank.
5 liters, settling tank capacity 3 liters
Into a sewage sludge treatment plant and pass artificial drainage water to 30 ° C.
And drained by venting at 5 liter / min. Artificial drainage
10% glucose, 10% peptone, ammonium chloride
10%, monopotassium phosphate 1%, monosodium phosphate 2
% And adjusted to pH 7.0. TOC load is 0.5
kg / m Three-The date and return rate were set to 50%.
【００１８】培養開始１０日後に沈殿槽で脱窒により活
性汚泥が浮上し始めた。１１日目に曝気槽に１ｍｇ／ｌ
になるように２−メルカプトベンゾイミダゾールを添加
した。薬剤投入１日後に活性汚泥の浮上は発生しなくな
り、この状態は１週間続いた。また処理水質はＴＯＣ
５〜２０ｍｇ／ｌであり、２−メルカプトベンゾイミダ
ゾール添加前と同等の水質が得られた。Activated sludge started to float by denitrification in the sedimentation tank 10 days after the start of the culture. 1 mg / l in the aeration tank on the 11th day
2-mercaptobenzimidazole was added to obtain. One day after the introduction of the chemical, the floating of the activated sludge did not occur, and this state continued for one week. The treated water quality is TOC
The water quality was 5 to 20 mg / l, and the same water quality as before addition of 2-mercaptobenzimidazole was obtained.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C02F 3/12 C02F 3/34 101 C02F 11/00 - 11/20 ──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. 7 , DB name) C02F 3/12 C02F 3/34 101 C02F 11/00-11/20
Claims (1)
イミダゾールを添加することを特徴とする活性汚泥の浮
上抑制方法。1. A method for suppressing floating of activated sludge, comprising adding 2-mercaptobenzimidazole to an activated sludge treatment system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17944796A JP3329195B2 (en) | 1996-07-09 | 1996-07-09 | Activated sludge floating control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17944796A JP3329195B2 (en) | 1996-07-09 | 1996-07-09 | Activated sludge floating control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1015576A JPH1015576A (en) | 1998-01-20 |
| JP3329195B2 true JP3329195B2 (en) | 2002-09-30 |
Family
ID=16066027
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17944796A Expired - Lifetime JP3329195B2 (en) | 1996-07-09 | 1996-07-09 | Activated sludge floating control method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3329195B2 (en) |
-
1996
- 1996-07-09 JP JP17944796A patent/JP3329195B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1015576A (en) | 1998-01-20 |
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