JP2003225698A - Method for reducing volume of excess sludge - Google Patents
Method for reducing volume of excess sludgeInfo
- Publication number
- JP2003225698A JP2003225698A JP2002021936A JP2002021936A JP2003225698A JP 2003225698 A JP2003225698 A JP 2003225698A JP 2002021936 A JP2002021936 A JP 2002021936A JP 2002021936 A JP2002021936 A JP 2002021936A JP 2003225698 A JP2003225698 A JP 2003225698A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen peroxide
- sludge
- excess sludge
- acetic acid
- peracetic acid
- 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.)
- Granted
Links
Landscapes
- Treatment Of Sludge (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、余剰汚泥の減容方
法に関する。TECHNICAL FIELD The present invention relates to a method for reducing excess sludge volume.
【０００２】[0002]
【従来の技術】従来、排水等の処理方法として、活性汚
泥を用いた生物学的処理方法が用いられている。この方
法は、汚水を活性汚泥槽に導入して曝気することによ
り、微生物等からなる活性汚泥によって汚水中の有機物
を分解処理するものである。この汚泥を含む処理水は、
処理水と汚泥に分離され、処理水は滅菌処理を経て河川
等に放流され、汚泥の一部は返送汚泥として活性汚泥槽
へ返送され、活性汚泥として再利用される。残りは余剰
汚泥として系外に出す。余剰汚泥は日本において、平成
４年には４億トンの工業廃棄物のうちの４５％を占め、
これを埋め立てる土地はもはやなくなりつつあり、近い
将来一杯になるであろうと言われている。また、処理に
要する費用は増加しつつあり、現在、都市部において１
トン当たり２万円の費用がかかる。余剰汚泥の焼却やＳ
ＣＦ（超臨界流体）処理も検討されているが、余剰汚泥
の増加に対しては根本的な対策とはいえない。2. Description of the Related Art Conventionally, a biological treatment method using activated sludge has been used as a treatment method for waste water and the like. In this method, sewage is introduced into an activated sludge tank and aerated, so that organic matter in the sewage is decomposed by activated sludge composed of microorganisms. The treated water containing this sludge is
It is separated into treated water and sludge, and the treated water is sterilized and discharged into rivers, etc., and part of the sludge is returned to the activated sludge tank as return sludge and reused as activated sludge. The rest is discharged outside the system as excess sludge. In Japan, excess sludge accounted for 45% of 400 million tons of industrial waste in 1992,
It is said that the land to fill this will be gone and will fill in the near future. In addition, the cost of processing is increasing, and it is currently 1
It costs 20,000 yen per ton. Incineration of excess sludge and S
CF (supercritical fluid) treatment is also being considered, but it cannot be said to be a fundamental measure against the increase in excess sludge.
【０００３】そこで、このような問題を解決するため
に、微生物によって分解されにくくなった余剰汚泥を酸
化分解して活性汚泥槽へ返送する量を多くし、余剰汚泥
を減量化することが検討されている。In order to solve such a problem, it is considered to reduce the amount of surplus sludge by increasing the amount of surplus sludge that has become difficult to be decomposed by microorganisms and returning it to the activated sludge tank. ing.
【０００４】現在まで、余剰汚泥を酸化処理する方法と
して、オゾン処理、ＯＨラジカル酸化、湿式酸化、およ
び過酸化水素による処理等が知られている。しかしなが
ら、オゾン処理、ＯＨラジカル酸化、および湿式酸化を
実用化するには、設備等に高いコストがかかるという問
題がある。また、フェントン法はＯＨラジカル酸化の機
構（Ｈ２Ｏ２＋Ｆｅ２＋→Ｆｅ３＋＋ＨＯ−＋ＯＨ・）
を用いるものであるが、コストが高いことに加え、環境
にやさしくない鉄を含む副産物を発生するという問題も
ある。Until now, ozone treatment, OH radical oxidation, wet oxidation, treatment with hydrogen peroxide and the like are known as methods for oxidizing excess sludge. However, in order to put ozone treatment, OH radical oxidation, and wet oxidation into practical use, there is a problem that equipment and the like are expensive. In addition, the Fenton method is a mechanism of OH radical oxidation (H 2 O 2 + Fe 2+ → Fe 3+ + HO − + OH.)
However, in addition to the high cost, there is a problem that a by-product containing iron, which is not environmentally friendly, is generated.
【０００５】特開２０００−３１２８９５号公報におい
ては、余剰汚泥を酸化するために過酸化水素を用い、さ
らにこの反応を効率的に行うためにｐＨ調整を組み合わ
せた方法が開示されている。この方法では、過酸化水素
と汚泥の反応を抑制するために硫酸等の酸が用いられ、
過酸化水素と汚泥の反応を促進するためにアルカリが用
いられている。しかしながら、ｐＨの調整と過酸化水素
の効力の関連性は明らかではなく、また、ここで使用さ
れる酸の生分解性も明らかではない。Japanese Unexamined Patent Publication No. 2000-31895 discloses a method in which hydrogen peroxide is used to oxidize excess sludge and pH adjustment is combined in order to efficiently carry out this reaction. In this method, an acid such as sulfuric acid is used to suppress the reaction between hydrogen peroxide and sludge,
Alkali is used to promote the reaction between hydrogen peroxide and sludge. However, the relationship between pH adjustment and the efficacy of hydrogen peroxide is not clear, nor is the biodegradability of the acid used here.
【０００６】[0006]
【発明が解決しようとする課題】従って、本発明は、生
分解性の優れた薬品を用いた、環境に有害な副産物を生
成することのない余剰汚泥の減容方法を提供しようとす
るものである。SUMMARY OF THE INVENTION Therefore, the present invention is intended to provide a method for reducing the volume of surplus sludge, which does not produce environmentally harmful by-products, using a chemical having excellent biodegradability. is there.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、上記課題
を解決すべく鋭意研究をした結果、過酸化水素と、酢酸
または過酢酸および酢酸との混合物を余剰汚泥に添加す
ると、相乗効果を生じ、過酸化水素を単独で加えるより
もより効果的に余剰汚泥を酸化することができることを
見出した。本発明はこの知見に基づく。Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that adding a mixture of hydrogen peroxide and acetic acid or peracetic acid and acetic acid to excess sludge produces a synergistic effect. It was found that the excess sludge can be oxidized more effectively than adding hydrogen peroxide alone. The present invention is based on this finding.
【０００８】すなわち、本発明によれば、排水等の生物
処理により生じる余剰汚泥の減容方法において、余剰汚
泥に酢酸および過酸化水素を添加して酸性にし、余剰汚
泥を過酸化水素で酸化した後、余剰汚泥を中性に戻して
残存する過酸化水素を分解させることを特徴とする方法
が提供される。That is, according to the present invention, in the method for reducing the volume of surplus sludge produced by biological treatment of wastewater, etc., acetic acid and hydrogen peroxide are added to the excess sludge to make it acidic, and the excess sludge is oxidized with hydrogen peroxide. Thereafter, a method is provided, which comprises returning the excess sludge to neutrality and decomposing the remaining hydrogen peroxide.
【０００９】また、本発明によれば、排水等の生物処理
により生じる余剰汚泥の減容方法において、余剰汚泥に
過酢酸、酢酸、および過酸化水素を添加して酸性にし、
余剰汚泥を過酢酸および過酸化水素で酸化した後、余剰
汚泥を中性に戻して残存する過酢酸および過酸化水素を
分解させることを特徴とする方法が提供される。Further, according to the present invention, in a method for reducing the volume of surplus sludge produced by biological treatment of wastewater, etc., peracetic acid, acetic acid, and hydrogen peroxide are added to the excess sludge to make it acidic.
A method is provided, which comprises oxidizing excess sludge with peracetic acid and hydrogen peroxide, and then returning the excess sludge to neutrality to decompose residual peracetic acid and hydrogen peroxide.
【００１０】さらに、上記混合物による相乗効果の原因
の一つはｐＨの低下であることから、余剰汚泥を酸性に
するために酢酸の代わりに二酸化炭素を使用することも
できる。Further, since one of the causes of the synergistic effect of the above mixture is the decrease in pH, carbon dioxide can be used in place of acetic acid to acidify the excess sludge.
【００１１】すなわち、本発明によれば、排水等の生物
処理により生じる余剰汚泥の減容方法において、余剰汚
泥に二酸化炭素および過酸化水素を添加して酸性にし、
余剰汚泥を過酸化水素で酸化した後、余剰汚泥を中性に
戻して残存する過酸化水素を分解させることを特徴とす
る方法も提供される。That is, according to the present invention, in the method for reducing the volume of excess sludge produced by biological treatment of wastewater, carbon dioxide and hydrogen peroxide are added to the excess sludge to make it acidic,
A method is also provided, which comprises oxidizing excess sludge with hydrogen peroxide, and then returning the excess sludge to neutrality to decompose residual hydrogen peroxide.
【００１２】これらの方法において、余剰汚泥を酸化す
るときに、余剰汚泥のｐＨを５．３未満にすることが好
ましい。In these methods, the pH of the excess sludge is preferably less than 5.3 when oxidizing the excess sludge.
【００１３】[0013]
【発明の実施の形態】以下、本発明をより詳しく説明す
る。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.
【００１４】本発明の第１の方法においては、余剰汚泥
を酸化する薬品として、過酸化水素と酢酸の混合物を用
いる。この混合物は水溶液として使用される。酢酸の添
加により余剰汚泥のｐＨが低くなると、汚泥中に存在す
るカタラーゼ（過酸化水素を分解する酵素であり、ｐＨ
５．３〜８で活性を持つ）は失活する。その結果、酸化
剤である過酸化水素は安定な状態となり、汚泥を効果的
に処理することができる。このとき、余剰汚泥のｐＨを
５．３未満にすることが好ましく、ｐＨ３〜４であるこ
とがより好ましい。この混合物を余剰汚泥に添加し、１
〜２時間放置して余剰汚泥を酸化処理する。In the first method of the present invention, a mixture of hydrogen peroxide and acetic acid is used as a chemical for oxidizing excess sludge. This mixture is used as an aqueous solution. When the pH of the surplus sludge becomes low due to the addition of acetic acid, the catalase (an enzyme that decomposes hydrogen peroxide,
(Active in 5.3-8) is deactivated. As a result, hydrogen peroxide, which is an oxidant, becomes stable and sludge can be effectively treated. At this time, the pH of the excess sludge is preferably less than 5.3, more preferably pH 3-4. Add this mixture to the excess sludge and
Let stand for ~ 2 hours to oxidize excess sludge.
【００１５】酢酸は生分解性に優れた薬品であり、環境
にやさしくない副産物を発生しないので、酸化処理され
た汚泥中に残存する酢酸については特別な処理をする必
要が無い。反応せずに汚泥中に残った過酸化水素がその
まま活性汚泥槽へ返送されると、活性汚泥にとって有害
な作用を及ぼす。しかし、処理後の汚泥を中性（ｐＨ
５．４〜８．２）に調整すると、汚泥中のカタラーゼが
活性化し、過酸化水素が分解される。このとき、ｐＨを
中性にするためには水酸化ナトリウム等の塩基を用いる
ことができる。また、必要であれば、過酸化水素を分解
するためにさらに余剰汚泥を添加することもできる。Since acetic acid is a highly biodegradable chemical and does not generate environmentally unfriendly by-products, acetic acid remaining in the oxidized sludge does not need to be treated specially. If the hydrogen peroxide remaining in the sludge without reacting is returned to the activated sludge tank as it is, it has a harmful effect on the activated sludge. However, the treated sludge is neutral (pH
When adjusted to 5.4 to 8.2), catalase in sludge is activated and hydrogen peroxide is decomposed. At this time, a base such as sodium hydroxide can be used to make the pH neutral. If necessary, excess sludge can be added to decompose hydrogen peroxide.
【００１６】本発明の第２の方法においては、余剰汚泥
を酸化する薬品として、過酸化水素、過酢酸および酢酸
の混合物を用いる。過酢酸は強力な酸化剤であるだけで
なく、環境にやさしい。過酢酸の分解生成物は過酸化水
素と酢酸であり、過酸化水素、酢酸、および過酢酸は、
次の式（１）で表されるような平衡状態を保ちながら共
存している。In the second method of the present invention, a mixture of hydrogen peroxide, peracetic acid and acetic acid is used as a chemical for oxidizing excess sludge. Not only is peracetic acid a strong oxidant, it is also environmentally friendly. The decomposition products of peracetic acid are hydrogen peroxide and acetic acid, and hydrogen peroxide, acetic acid, and peracetic acid are
They coexist while maintaining an equilibrium state represented by the following formula (1).
【００１７】Ｈ２Ｏ２＋ＣＨ３ＣＯＯＨ← →ＣＨ３Ｃ
ＯＯＯＨ＋Ｈ２Ｏ・・・（１）したがって、余剰汚泥に
これらの混合物を添加すると、酢酸によりｐＨが低下し
てカタラーゼが失活する。なお、過酢酸は強力な酸化剤
であるので、過酸化水素を単独で加えるときよりもより
効果的に汚泥を酸化することができる。このとき、余剰
汚泥のｐＨについては酢酸の量により、第１の発明と同
様に設定する。H 2 O 2 + CH 3 COOH ← → CH 3 C
OOOH + H 2 O (1) Therefore, when these mixtures are added to the excess sludge, the pH is lowered by acetic acid and the catalase is deactivated. Since peracetic acid is a strong oxidant, it can oxidize sludge more effectively than when hydrogen peroxide is added alone. At this time, the pH of the excess sludge is set in the same manner as in the first invention, depending on the amount of acetic acid.
【００１８】反応せずに汚泥中に残った過酢酸および過
酸化水素がそのまま活性汚泥槽へ返送されると、活性汚
泥にとって有害な作用を及ぼす。しかし、処理後の汚泥
のｐＨを中性に調整すると、汚泥中に残るカタラーゼが
活性化し、過酸化水素が分解される。これに伴い、式
（１）の平衡が左に移行するため、過酢酸も順次分解さ
れ、その結果として生分解性に優れた酢酸が生成する。
また、必要であれば、過酸化水素を分解するためにさら
に余剰汚泥を添加することもできる。If the peracetic acid and hydrogen peroxide remaining in the sludge without reacting are returned to the activated sludge tank as they are, they have a harmful effect on the activated sludge. However, if the pH of the treated sludge is adjusted to neutral, the catalase remaining in the sludge is activated and hydrogen peroxide is decomposed. Along with this, since the equilibrium of the formula (1) shifts to the left, peracetic acid is also sequentially decomposed, and as a result, acetic acid excellent in biodegradability is produced.
If necessary, excess sludge can be added to decompose hydrogen peroxide.
【００１９】また、余剰汚泥のｐＨを低下させるため
に、酢酸の代わりに二酸化炭素を用いることもできる。
二酸化炭素は気体の状態で添加し、余剰汚泥がｐＨ５．
３未満になるように使用する。例えば、余剰汚泥に１ａ
ｔｍで二酸化炭素を注入して飽和させると、余剰汚泥の
ｐＨは約５．２になる。圧力を上昇させることによりさ
らにｐＨの低下が期待できる。通常、この操作は１〜３
ａｔｍ程度の圧力で行う。二酸化炭素を用いてｐＨを低
下させた場合、酸化処理後の汚泥は、曝気することによ
り容易にｐＨを中性に戻すことができる。また、この方
法は、有機化合物を添加せずに反応を行えるという利点
がある。Carbon dioxide may be used in place of acetic acid in order to lower the pH of the excess sludge.
Carbon dioxide is added in a gaseous state, and excess sludge has a pH of 5.
Use so that it is less than 3. For example, 1a for excess sludge
When the carbon dioxide is injected and saturated at tm, the pH of the excess sludge becomes about 5.2. A further decrease in pH can be expected by increasing the pressure. Usually, this operation is 1-3
It is performed at a pressure of about atm. When the pH is lowered by using carbon dioxide, the sludge after the oxidation treatment can be easily returned to the neutral pH by aeration. Further, this method has an advantage that the reaction can be performed without adding an organic compound.
【００２０】以上のようにして余剰汚泥の酸化処理と、
過酸化水素の分解を行った後に、処理汚泥を活性汚泥槽
に返送することができるので、本発明の方法は余剰汚泥
の減量化に有効であり、しかも環境に有害な副産物を生
成することがない。As described above, the oxidation treatment of excess sludge,
Since the treated sludge can be returned to the activated sludge tank after the decomposition of hydrogen peroxide, the method of the present invention is effective in reducing the amount of excess sludge, and can produce environmentally harmful byproducts. Absent.
【００２１】[0021]
【実施例】以下本発明を実施例により説明するが、本発
明はそれらに限定されるものではない。EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.
【００２２】Ａ．生物学的試験
実験方法
この実験には、約０．４５％過酢酸、約５％酢酸、およ
び８％過酸化水素をそれぞれ用いた。A. Biological Testing Experimental Method About 0.45% peracetic acid, about 5% acetic acid, and 8% hydrogen peroxide were used for this experiment, respectively.
【００２３】１．試料の調製
所定量の上記試薬に１ｍＬの汚泥を添加し、トータルの
体積が５ｍＬとなるように水を添加する。この混合液を
室温で２時間放置し、これを試験試料とする。1. Preparation of sample 1 mL of sludge is added to a predetermined amount of the above reagent, and water is added so that the total volume becomes 5 mL. This mixed solution is left at room temperature for 2 hours, and this is used as a test sample.
【００２４】２．コロニー形成単位（ＣＦＵ）の測定
試料から１０００μＬ取り、９ｍＬのＰＢＳ（−）で希
釈する。またその液を１ｍＬ取って９ｍＬのＰＢＳ
（−）で希釈し、これを繰り返すことにより試料を１０
−６まで希釈する。次に、ＰＢＳ（−）で希釈した試料
をペトリフィルムに１ｍＬ取る。３０℃で２日間インキ
ュベート後、ペトリフィルム上のコロニー数を計測す
る。2. 1000 μL is taken from the measurement sample of colony forming unit (CFU) and diluted with 9 mL of PBS (−). Also, take 1 mL of the solution and add 9 mL of PBS.
Dilute with (-) and repeat this to give 10
Dilute to -6 . Next, 1 mL of the sample diluted with PBS (-) is taken on a Petri film. After incubating at 30 ° C. for 2 days, the number of colonies on the Petri film is counted.
【００２５】３．濁度試験
１００μＬの試料を５ｍＬの栄養ブロスに添加する。こ
れを３０℃で２日間インキュベート後、ＵＶ分光光度計
を用いて波長６８０ｎｍにおける濁度を測定する。3. Turbidity test Add 100 μL of sample to 5 mL of nutrient broth. After incubating this at 30 ° C. for 2 days, the turbidity at a wavelength of 680 nm is measured using a UV spectrophotometer.
【００２６】相乗効果判定基準
過酸化水素と酢酸または過酢酸を同時に使用することに
よる相乗効果を判定する基準として、ＦＩＣ（ｆｒａｃ
ｔｉｏｎａｌ ｉｎｈｉｂｉｔｏｒｙ ｃｏｎｃｅｎｔｒ
ａｔｉｏｎ）を用いる。これは、次の式（２）により算
出する。Criteria for judging synergistic effect As a standard for judging the synergistic effect of using hydrogen peroxide and acetic acid or peracetic acid at the same time, FIC (frac)
regional inhibtory concentr
ation) is used. This is calculated by the following equation (2).
【００２７】
ＦＩＣ＝ＭＩＣａｂ／ＭＩＣａ＋ＭＩＣｂａ／ＭＩＣｂ・・・（２）
ここで、ＭＩＣａは、薬品Ａ単独での最小阻止濃度を、
ＭＩＣｂは、薬品Ｂ単独での最小阻止濃度を、ＭＩＣ
ａｂは、薬品Ｂの存在下での薬品Ａの最小阻止濃度を、
ＭＩＣｂａは、薬品Ａの存在下での薬品Ｂの最小阻止濃
度をそれぞれ表す。ここで、最小阻止濃度は、濁度試験
において濁度の変化が認められない（すなわち、微生物
の生育を阻害する）最小の濃度を求めることにより決定
した。この式から算出されるＦＩＣの値が１未満である
ときに、薬品Ａと薬品Ｂの間に相乗効果があると判断す
る。なお、本実験においては、Ａは過酢酸または酢酸、
Ｂは過酸化水素を表す。FIC = MIC ab / MIC a + MIC ba / MIC b (2) Here, MIC a is the minimum inhibitory concentration of the drug A alone,
MIC b is the minimum inhibitory concentration of chemical B alone.
ab is the minimum inhibitory concentration of drug A in the presence of drug B,
MIC ba represents the minimum inhibitory concentration of drug B in the presence of drug A, respectively. Here, the minimum inhibitory concentration was determined by determining the minimum concentration at which no change in turbidity was observed in the turbidity test (that is, the growth of microorganisms was inhibited). When the FIC value calculated from this formula is less than 1, it is determined that there is a synergistic effect between the medicine A and the medicine B. In this experiment, A is peracetic acid or acetic acid,
B represents hydrogen peroxide.
【００２８】実験結果
以下の実験において、過酸化水素に過酢酸を混合したも
のは、過酸化水素、過酢酸および酢酸の混合物を使用し
ていることを意味する。また、実験結果を示す図におけ
る、「過酢酸」の表示も、過酸化水素、過酢酸および酢
酸の混合物を使用していることを意味する。Experimental Results In the following experiments, the mixture of hydrogen peroxide with peracetic acid means that a mixture of hydrogen peroxide, peracetic acid and acetic acid is used. In addition, the expression "peracetic acid" in the figures showing the experimental results also means that a mixture of hydrogen peroxide, peracetic acid and acetic acid is used.
【００２９】図１は、汚泥（微生物）を不活性化するの
に最低限必要な過酸化水素と酢酸または過酢酸の量の関
係を示すグラフである。縦軸は酢酸または過酢酸の使用
量（ｍＬ）を、横軸は過酸化水素の量（ｍＬ）を示す。
グラフ中の数値は、各測定における上記式（２）により
算出されたＦＩＣの値である。本実験は、上記実験方法
１および３に従って行った。用いた汚泥は浮遊物量（Ｓ
Ｓ）＝１１ｇ／Ｌであり、試薬を添加しないで同様に調
製したブランク試料のＣＦＵは２×１０６であった。FIG. 1 is a graph showing the relationship between the minimum amount of hydrogen peroxide and acetic acid or peracetic acid required to inactivate sludge (microorganisms). The vertical axis represents the amount of acetic acid or peracetic acid used (mL), and the horizontal axis represents the amount of hydrogen peroxide (mL).
The numerical values in the graph are FIC values calculated by the above equation (2) in each measurement. This experiment was performed according to the above-mentioned experimental methods 1 and 3. The sludge used is the amount of suspended solids (S
S) = 11 g / L, and the CFU of the blank sample prepared in the same manner without adding the reagent was 2 × 10 6 .
【００３０】１ｍＬ以下の範囲の所定量の過酸化水素と
種々の量の酢酸または過酢酸を含む試料を調製し、各量
の過酸化水素の存在下で微生物の生育を阻害するのに最
低限必要な酢酸または過酢酸の量を調べた。Samples containing a predetermined amount of hydrogen peroxide in the range of 1 mL or less and various amounts of acetic acid or peracetic acid were prepared, and the minimum amount for inhibiting the growth of microorganisms in the presence of each amount of hydrogen peroxide was prepared. The amount of acetic acid or peracetic acid required was investigated.
【００３１】なお、各試薬を単独で用いた場合に汚泥を
不活性化するのに最低限必要となる量はそれぞれ、酢酸
で２．６ｍＬ以上、過酸化水素で２．０ｍＬ、過酢酸で
０．７５ｍＬであった。The minimum amount required to inactivate the sludge when each reagent is used alone is 2.6 mL or more for acetic acid, 2.0 mL for hydrogen peroxide, and 0 mL for peracetic acid. It was 0.75 mL.
【００３２】その結果、図１に示されるように、過酸化
水素に酢酸または過酢酸を混合したいずれの場合もＦＩ
Ｃ値は１未満であり、これら２種の試薬を混合すること
により相乗効果が生じることが明らかとなった。また、
酢酸よりも過酢酸の方が、過酸化水素に対して少量で汚
泥を不活性化することができ、より高い相乗効果を生じ
ることも明らかとなった。As a result, as shown in FIG. 1, FI was obtained when hydrogen peroxide was mixed with acetic acid or peracetic acid.
The C value was less than 1, and it was revealed that mixing these two types of reagents produces a synergistic effect. Also,
It was also clarified that peracetic acid was able to inactivate sludge in a small amount with respect to hydrogen peroxide, and produced higher synergistic effect than acetic acid.
【００３３】図１の実験に用いた試料のｐＨは３〜３．
７の範囲であった。酢酸または過酢酸の添加により余剰
汚泥のｐＨが低くなり、汚泥中に存在するカタラーゼが
失活した結果、酸化剤である過酸化水素が安定な状態と
なり、汚泥を効果的に処理することができるようになっ
たと考えられる。The pH of the sample used in the experiment of FIG.
The range was 7. The pH of the excess sludge is lowered by the addition of acetic acid or peracetic acid, and the catalase present in the sludge is deactivated. As a result, hydrogen peroxide, which is an oxidizer, is in a stable state, and sludge can be effectively treated. It is believed that
【００３４】図２は、過酸化水素に過酢酸または酢酸を
混合して汚泥に添加したときの、試薬の量と微生物の生
存数（ＣＦＵ）の関係を表したグラフである。縦軸は微
生物のＣＦＵを、横軸は加えた酢酸または過酢酸の量
（ｍＬ）を表す。本実験は、上記実験方法１および２に
従って行った。使用した汚泥はＳＳ＝１１．２ｇ／Ｌで
あり、試薬を添加していないブランク試料のＣＦＵは２
×１０６であった。０．２５ｍＬの過酸化水素と、０．
２ｍＬ以下の酢酸または過酢酸を含む試料についてそれ
ぞれＣＦＵを測定した結果、図２に示されるように、過
酸化水素に酢酸または過酢酸を加えた試薬を用いること
により、微生物の生存数は劇的に減少することが明らか
となった。また、過酢酸の方が酢酸よりもその効果は大
きいことが分かる。FIG. 2 is a graph showing the relationship between the amount of reagents and the survival number (CFU) of microorganisms when peracetic acid or acetic acid is mixed with hydrogen peroxide and added to sludge. The vertical axis represents the CFU of the microorganism, and the horizontal axis represents the amount of acetic acid or peracetic acid added (mL). This experiment was performed according to the above-mentioned experimental methods 1 and 2. The sludge used was SS = 11.2 g / L, and the CFU of the blank sample without addition of reagents was 2
It was × 10 6 . 0.25 mL hydrogen peroxide and 0.
As a result of measuring CFU for a sample containing 2 mL or less of acetic acid or peracetic acid, as shown in FIG. 2, by using a reagent in which acetic acid or peracetic acid was added to hydrogen peroxide, the survival number of microorganisms was dramatically increased. It became clear that it decreased to. Further, it can be seen that peracetic acid has a greater effect than acetic acid.
【００３５】Ｂ．酸化能試験
図３は、過酸化水素に、酢酸、または酢酸および過酢酸
を添加したときの、酸化還元電位を表すグラフである。
用いた試薬は、ａ：８％過酸化水素、ｂ：８％過酸化水
素＋５％酢酸、およびｃ：６％過酸化水素＋４％酢酸＋
０．３％過酢酸である。これより、過酸化水素のみより
も、酢酸を添加した方が、さらに酢酸および過酢酸を添
加した方が酸化還元電位が高くなり、酸化力が強いこと
が予想される。B. Oxidation ability test FIG. 3 is a graph showing the redox potential when acetic acid or acetic acid and peracetic acid are added to hydrogen peroxide.
The reagents used were a: 8% hydrogen peroxide, b: 8% hydrogen peroxide + 5% acetic acid, and c: 6% hydrogen peroxide + 4% acetic acid +
0.3% peracetic acid. From this, it is expected that the addition of acetic acid and the addition of acetic acid and peracetic acid increase the redox potential and the oxidizing power is stronger than hydrogen peroxide alone.
【００３６】Ｃ．過酸化水素の安定化試験
図４は、８％過酸化水素（ｐＨ６〜７）、または８％過
酸化水素と５％酢酸の混合物（ｐＨ３〜４）に汚泥を添
加する前後における、試料中の過酸化水素の濃度を表し
たグラフである。横軸は汚泥添加前の過酸化水素濃度
（％）、縦軸は汚泥添加後の過酸化水素濃度（％）を示
す。各濃度の過酸化水素のみを含む試薬、または酢酸が
共存している各濃度の過酸化水素を含む試薬に、ＳＳ＝
１４．４ｇ／Ｌの汚泥１００μＬを添加し、室温で５ｍ
ｉｎ程度放置後、過酸化水素の濃度を測定した。その結
果、図４に示されるように、過酸化水素のみを含む試薬
を用いるとそのほとんどが分解されてしまうが、過酸化
水素と酢酸を含む試薬を用いると過酸化水素の大部分が
分解されずに残ることが分かった。これは、酢酸により
ｐＨが低くなり、汚泥中に存在する過酸化水素を分解す
るカタラーゼが失活するためであると考えられる。C. Stabilization test of hydrogen peroxide Fig. 4 shows a sample of the sample before and after adding sludge to 8% hydrogen peroxide (pH 6 to 7) or a mixture of 8% hydrogen peroxide and 5% acetic acid (pH 3 to 4). It is a graph showing the concentration of hydrogen peroxide. The horizontal axis shows the hydrogen peroxide concentration (%) before addition of sludge, and the vertical axis shows the hydrogen peroxide concentration (%) after addition of sludge. For a reagent containing only hydrogen peroxide at each concentration or a reagent containing hydrogen peroxide at each concentration in the presence of acetic acid, SS =
100 μL of 14.4 g / L sludge was added, and 5 m at room temperature
After standing for about in, the concentration of hydrogen peroxide was measured. As a result, as shown in FIG. 4, most of the hydrogen peroxide is decomposed by using the reagent containing only hydrogen peroxide, but most of the hydrogen peroxide is decomposed by using the reagent containing hydrogen peroxide and acetic acid. It turns out that it remains. It is considered that this is because acetic acid lowers the pH and deactivates catalase that decomposes hydrogen peroxide present in sludge.
【００３７】Ｄ．過酸化水素の分解試験
処理済の余剰汚泥を過酸化水素が残ったままで活性汚泥
槽に返送すると、活性汚泥槽での微生物処理にとって有
害な影響を及ぼす。したがって、活性汚泥槽に返送する
前に残存している過酸化水素が分解されていなければな
らない。本発明においては、処理済の余剰汚泥のｐＨ値
を中性の範囲に戻し、カタラーゼを活性化させることに
より、過酸化水素を分解する。図５は、中性の汚泥中に
存在する過酸化水素の濃度と時間経過の関係を表したグ
ラフである。縦軸は汚泥添加後の過酸化水素の濃度
（％）、横軸は添加してからの経過時間（ｍｉｎ）を表
す。１ｍＬの８％過酸化水素に、ＳＳ＝１９．４ｇ／Ｌ
の中性汚泥を１ｍＬまたは２ｍＬ添加して、５分おきに
過酸化水素の濃度を測定した。その結果、図５に示され
るように、過酸化水素の濃度は時間経過に伴って減少す
ることが分かった。特に、過酸化水素に中性汚泥を２ｍ
Ｌ添加した場合には、約５分間で過酸化水素濃度がほぼ
検出限界（図中、ＤＬで表示）まで減少することが分か
った。D. Hydrogen peroxide decomposition test Returning excess sludge that has been treated to the activated sludge tank with hydrogen peroxide still remaining has a harmful effect on microbial treatment in the activated sludge tank. Therefore, the remaining hydrogen peroxide must be decomposed before it is returned to the activated sludge tank. In the present invention, the hydrogen peroxide is decomposed by returning the pH value of the treated excess sludge to the neutral range and activating catalase. FIG. 5 is a graph showing the relationship between the concentration of hydrogen peroxide present in neutral sludge and the passage of time. The vertical axis represents the concentration (%) of hydrogen peroxide after addition of sludge, and the horizontal axis represents the elapsed time (min) after addition. SS = 19.4 g / L in 1 mL of 8% hydrogen peroxide
1 mL or 2 mL of neutral sludge was added and the concentration of hydrogen peroxide was measured every 5 minutes. As a result, as shown in FIG. 5, it was found that the concentration of hydrogen peroxide decreased with time. Especially, 2m neutral sludge in hydrogen peroxide
It was found that when L was added, the hydrogen peroxide concentration decreased to about the detection limit (indicated by DL in the figure) in about 5 minutes.
【００３８】Ｅ．二酸化炭素の使用
前述した実験結果から、過酸化水素と酢酸の混合物を汚
泥に添加すると、相乗効果を生じ、過酸化水素単独で添
加するよりも効果的に汚泥を酸化できることが明らかと
なった。これは酢酸によりｐＨが低下することが原因で
ある。そこで、ｐＨを下げる物質として、酢酸の代わり
に二酸化炭素を用いて実験を行ったのが図６である。ブ
ランク試料としてＳＳ＝１６．６ｇ／Ｌの汚泥１００ｍ
Ｌを用いた。また、この汚泥１００ｍＬに０．５ｍＬの
８％過酸化水素を添加した試料、およびこれにさらに１
ａｔｍで二酸化炭素を飽和させてｐＨを５．２にした試
料を調製した。それぞれの試料について、前述したＡ．
生物学的試験の実験方法２に従ってＣＦＵを測定した。
その結果、二酸化炭素を添加したことにより、生存する
微生物が減少した。E. Use of carbon dioxide From the above experimental results, it became clear that adding a mixture of hydrogen peroxide and acetic acid to sludge produces a synergistic effect, and can oxidize sludge more effectively than adding hydrogen peroxide alone. This is because acetic acid lowers the pH. Therefore, FIG. 6 shows an experiment conducted using carbon dioxide instead of acetic acid as a substance for lowering the pH. 100m of sludge with SS = 16.6g / L as a blank sample
L was used. In addition, a sample in which 0.5 mL of 8% hydrogen peroxide was added to 100 mL of this sludge, and further 1
A sample having a pH of 5.2 was prepared by saturating carbon dioxide at atm. For each sample, the A.
CFU was measured according to Experimental Method 2 of the Biological Test.
As a result, the addition of carbon dioxide reduced the viable microorganisms.
【００３９】[0039]
【発明の効果】以上詳述したように、本発明によれば、
生分解性に優れた薬品を用いて、環境に有害な副産物を
生成すること無く余剰汚泥を減容できる。As described in detail above, according to the present invention,
By using chemicals with excellent biodegradability, the volume of excess sludge can be reduced without producing environmentally harmful by-products.
【図１】汚泥を不活性化するのに最低限必要な薬品の量
の関係を表すグラフ。FIG. 1 is a graph showing the relationship between the minimum amount of chemicals required to inactivate sludge.
【図２】汚泥に薬品を加えたときの微生物の生存数を表
すグラフ。FIG. 2 is a graph showing the survival number of microorganisms when chemicals are added to sludge.
【図３】過酸化水素に、酢酸、または酢酸および過酢酸
を混合したときの、酸化還元電位を表すグラフ。FIG. 3 is a graph showing a redox potential when hydrogen peroxide is mixed with acetic acid or acetic acid and peracetic acid.
【図４】薬品に汚泥を添加する前後における過酸化水素
の濃度を表すグラフ。FIG. 4 is a graph showing the concentration of hydrogen peroxide before and after adding sludge to a chemical.
【図５】汚泥中で分解される過酸化水素の濃度変化を表
すグラフ。FIG. 5 is a graph showing changes in the concentration of hydrogen peroxide decomposed in sludge.
【図６】汚泥に、過酸化水素、または過酸化水素および
二酸化炭素を添加したときの微生物の生存数を表すグラ
フ。FIG. 6 is a graph showing the survival number of microorganisms when hydrogen peroxide or hydrogen peroxide and carbon dioxide are added to sludge.
───────────────────────────────────────────────────── フロントページの続き (71)出願人 595179619 75 Ｑｕａｉ ｄ’Ｏｒｓａｙ 75321 Ｐａｒｉｓ Ｃｅｄｅｘ 07 Ｆｒａｎｃ ｅ (72)発明者 孫 旭臨 茨城県つくば市松代４−15−２−２−304 (72)発明者 石橋 淳子 茨城県つくば市春日３−13−１ ソレイ ユ・タカノ ナンバー 505 Ｆターム(参考） 4D059 AA05 BC05 BF12 DA37 DA44 DB08 EA05 EB05 ─────────────────────────────────────────────────── ─── Continued front page (71) Applicant 595179619 75 Quai d'Orsay 75321 Paris Cedex 07 Franc e (72) Inventor Son Asahi Rin 4-15-2-2-304 Matsushiro Tsukuba City, Ibaraki Prefecture (72) Inventor Junko Ishibashi 3-13-1 Kasuga, Tsukuba City, Ibaraki Prefecture Yo Takano number 505 F term (reference) 4D059 AA05 BC05 BF12 DA37 DA44 DB08 EA05 EB05
Claims (4)
の減容方法において、前記余剰汚泥に酢酸および過酸化
水素を添加して酸性にし、前記余剰汚泥を前記過酸化水
素で酸化した後、前記余剰汚泥を中性に戻して残存する
前記過酸化水素を分解させることを特徴とする方法。1. A method for reducing the volume of surplus sludge produced by biological treatment of wastewater or the like, wherein acetic acid and hydrogen peroxide are added to the surplus sludge to make it acidic, and the surplus sludge is oxidized with the hydrogen peroxide, A method comprising returning excess sludge to neutrality to decompose the remaining hydrogen peroxide.
の減容方法において、前記余剰汚泥に過酢酸、酢酸、お
よび過酸化水素を添加して酸性にし、前記余剰汚泥を前
記過酢酸および過酸化水素で酸化した後、前記余剰汚泥
を中性に戻して残存する前記過酢酸および過酸化水素を
分解させることを特徴とする方法。2. A method for reducing the volume of excess sludge produced by biological treatment of wastewater, etc., wherein the excess sludge is acidified by adding peracetic acid, acetic acid, and hydrogen peroxide, and the excess sludge is converted to the peracetic acid and peroxidation. After oxidizing with hydrogen, the excess sludge is returned to neutral to decompose the remaining peracetic acid and hydrogen peroxide.
の減容方法において、前記余剰汚泥に二酸化炭素および
過酸化水素を添加して酸性にし、前記余剰汚泥を前記過
酸化水素で酸化した後、前記余剰汚泥を中性に戻して残
存する前記過酸化水素を分解させることを特徴とする方
法。3. A method for reducing the volume of excess sludge produced by biological treatment of wastewater, etc., wherein carbon dioxide and hydrogen peroxide are added to the excess sludge to make it acidic, and the excess sludge is oxidized with the hydrogen peroxide, A method comprising returning the excess sludge to neutrality to decompose the remaining hydrogen peroxide.
剰汚泥のｐＨを５．３未満にすることを特徴とする請求
項１ないし３のいずれか１項記載の方法。4. The method according to claim 1, wherein when oxidizing the excess sludge, the pH of the excess sludge is set to less than 5.3.
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|---|---|---|---|
| JP2002021936A JP3828429B2 (en) | 2002-01-30 | 2002-01-30 | Volume reduction method of excess sludge |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2316303A1 (en) * | 2007-09-25 | 2009-04-01 | Universidad De Almeria | Method of conditioning of compost with a solution of peroxyacetic mixture |
| WO2009099209A1 (en) * | 2008-02-08 | 2009-08-13 | Mitsubishi Heavy Industries, Ltd. | Apparatus and method for treatment of radioactive nitrate salt liquid waste |
-
2002
- 2002-01-30 JP JP2002021936A patent/JP3828429B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2316303A1 (en) * | 2007-09-25 | 2009-04-01 | Universidad De Almeria | Method of conditioning of compost with a solution of peroxyacetic mixture |
| WO2009040447A1 (en) * | 2007-09-25 | 2009-04-02 | Universidad De Almería | Method of conditioning of compost with a solution of peroxyacetic mixture |
| WO2009099209A1 (en) * | 2008-02-08 | 2009-08-13 | Mitsubishi Heavy Industries, Ltd. | Apparatus and method for treatment of radioactive nitrate salt liquid waste |
| JP2009186437A (en) * | 2008-02-08 | 2009-08-20 | Mitsubishi Heavy Ind Ltd | Radioactive nitrate waste liquid treating apparatus |
| EP2242061A1 (en) * | 2008-02-08 | 2010-10-20 | Mitsubishi Heavy Industries, Ltd. | Apparatus and method for treatment of radioactive nitrate salt liquid waste |
| US8696892B2 (en) | 2008-02-08 | 2014-04-15 | Mitsubishi Heavy Industries, Ltd. | Apparatus for treating radioactive nitrate waste liquid |
| EP2242061A4 (en) * | 2008-02-08 | 2015-04-22 | Mitsubishi Heavy Ind Ltd | Apparatus and method for treatment of radioactive nitrate salt liquid waste |
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| Publication number | Publication date |
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