JP3401863B2 - Method and agent for suppressing filamentous bulking - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an inhibitor for suppressing filamentous bulking in an activated sludge treatment system.

[0002]

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 to be aerated, the sludge is separated in a solid-liquid separation tank, and the separated liquid is discharged as treated water while being separated. A part of the generated sludge is returned to the aeration tank as return sludge, and the rest is discharged as excess sludge. In such an activated sludge treatment method, organic matter is decomposed by activated sludge in which bacteria such as zooglare are dominant, but filamentous bacteria such as sphaerotils grow in the activated sludge depending on the properties of raw water and various treatment conditions. Then, filamentous bulking may occur. Filamentous bulking is a phenomenon in which activated sludge is lightened by the growth of filamentous bacteria and the separability is deteriorated. When such bulking occurs, it becomes difficult to separate the sludge in the solid-liquid separation tank, and the sludge flows out together with the treated water, so that it is not possible to secure sufficient return sludge and the treatment performance deteriorates.

Conventionally, in order to prevent such filamentous bulking, there has been a method of suppressing the growth of filamentous bacteria by adding various bactericides, and a quaternary ammonium salt is used as a bactericide. Japanese Examined Patent Publication No. 63-39562 shows that benzalkonium chloride, benzethonium chloride, and a mixture thereof can sterilize only filamentous bacteria and suppress bulking without affecting other bacteria.

[0004]

However, in general, the quaternary ammonium salt is a bactericidal agent, so that it also suppresses the growth of bacteria other than filamentous bacteria and also affects humans and animals. (For example, Japanese Patent Publication No. 3-38)
No. 000). An object of the present invention is to propose a method and an inhibitor for filamentous bulking that can effectively inhibit filamentous bulking without harming bacteria other than filamentous bacteria and humans and animals.

[0005]

The present invention provides the following filamentous bar.
A method and an agent for suppressing luking. (1) Mixing in the aeration tank from any place in the activated sludge treatment system
A method for suppressing filamentous bulking, which comprises adding an anionic or nonionic surfactant to a liquid . (2) In the aeration tank of the activated sludge treatment system or its pre-process,
Adding a nonionic or nonionic surfactant
(1) A method for suppressing filamentous bulking according to the above (1)
Law. (3) The anionic surfactant is a higher alcohol sulfate.
Stellite salt, higher alkyl ether sulfate ester salt, sulfuric acid
Petroleum oil, sulfated fatty acid ester, sulfated olefin, al
Killbenzene sulfonate, alkyl naphthalene sulfo
Phosphates, paraffin sulfonates, and higher alcohols
One or more kinds of surface activity selected from the group consisting of luphosphates
(1) or (2) above, which is characterized by being an agent
Method for suppressing filamentous bulking of. (4) The nonionic surfactant is HLB8-18.
Higher alcohol ethylene oxide adduct, alkylphen
Nol ethylene oxide adduct, fatty acid ethyleneoxy
De-adduct, polyhydric alcohol fatty acid ester ethylene oki
Cid adducts, ethylene oxide adducts of fats and oils, propylene
N-glycol ethylene oxide adduct, glycerol
Fatty acid ester, fatty acid ester of pentaerythritol
Fatty acid esters of le, sorbitol and sorbitan,
Sucrose fatty acid ester, polyhydric alcohol alkyl ether
Ether and fatty acid amides of alkanolamines
Be at least one surfactant selected from the group consisting of
A filamentous ball according to (1) or (2) above, characterized in that
King suppression method. (5) Mixing in the aeration tank from any place in the activated sludge treatment system
Anionic or nonionic surfactant is used for the liquid
Specially added to be 5 to 1000 mg / L
The yarn according to any one of the above (1) to (4)
Of suppressing bulky bulking. (6) Mixing in the aeration tank from any place in the activated sludge treatment system
For liquids, with anionic or nonionic surfactant
Characterized by adding an antifoaming agent simultaneously or separately
Filiform ball according to any one of (1) to (5) above
King suppression method. (7) Mixing in the aeration tank from any place in the activated sludge treatment system
It is an inhibitor of filamentous bulking added to liquids.
Te, comprise anionic or nonionic surfactants
A filamentous bulking inhibitor characterized by: (8) Higher alcohol sulfate ester salt, higher alkyl ester
-Ether sulfate ester, sulfated oil, sulfated fatty acid ester
, Sulfated olefin, Alkylbenzene sulfonic acid
Salt, alkylnaphthalene sulfonate, paraffin sulphate
Is it a group consisting of phonates and higher alcohol phosphates?
Contain one or more anionic surfactants selected from
Suppression of filamentous bulking according to (7) above
Agent. (9) Higher alcohol ethylene which is HLB 8-18
Xide adduct, with alkylphenol ethylene oxide
Additives, fatty acid ethylene oxide adducts, polyhydric alcohols
Fatty acid ester ethylene oxide adduct, fat and oil
Oxide adduct, propylene glycol ethylene oxide
Cid adduct, fatty acid ester of glycerol, pentae
Fatty acid esters of lysitol, sorbitol and sodium
Rubitan fatty acid ester, sucrose fatty acid ester,
Alkyl ethers of polyhydric alcohols and alkanos
One selected from the group consisting of fatty acid amides of ruamines
Including the above nonionic surfactant
The inhibitor for filamentous bulking according to item (7). (10) Anionic surfactant or nonionic surfactant
(7) or (7) which is characterized by containing a demulcent and an antifoaming agent
The inhibitor for filamentous bulking according to any one of (9).

[0006] In the present invention, the activated sludge treatment system, showing a processing system in any way of performing aerobic treatment with activated sludge, in addition to the conventional activated sludge treatment method, and variations thereof and other processing methods It includes the processing system in the processing method by combination. Here, the treatment system means the entire system for performing the above treatment , and mixing from any place in the treatment system in the aeration tank.
Bulking can be suppressed by adding a surfactant to the liquid . Further, in the present invention, the term “suppress” means to suppress the occurrence of bulking and also to suppress the progress and expansion of the bulking that has already occurred.

Surfactants which can be used in the present invention are
It is an anionic or nonionic surfactant, and the type thereof is not limited, and may be a naturally derived surfactant or a synthetic product. Such anionic or nonionic surfactants are also used for household use, and are safe without any harm to bacteria other than filamentous bacteria and humans and animals. In particular,
Nonionic surfactants are preferable because they adsorb to sludge better than anionic ones and transfer to treated water less.

Examples of anionic surfactants include:
Carboxylic acid salts such as soaps; higher alcohol sulfate ester salts, higher alkyl ether sulfate ester salts, sulfated oils, sulfated fatty acid esters, sulfated ether salts such as sulfated olefins; alkylbenzene sulfonates, alkylnaphthalenesulfonates, paraffins Examples thereof include sulfonates such as sulfonates; phosphate ester salts such as higher alcohol phosphate esters.

Examples of nonionic surfactants include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts. Polyethylene glycol type such as ethylene oxide adduct of fats and oils, polypropylene glycol ethylene oxide adduct, etc .; fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, alkanolamine Examples thereof include polyhydric alcohol types such as fatty acid amides. Particularly, an alkylphenol ethylene oxide adduct and a higher alcohol ethylene oxide adduct are preferable. As the nonionic surfactant, those having HLB 8 to 18 are preferable, and those having HLB 10 to 15 are most preferable.

These surfactants may be used alone or in combination of several kinds to aerate from any place in the activated sludge treatment system.
It can be added to the mixed solution in the tank, but is particularly preferably added to the aeration tank. The amount of surfactant added is
The type, addition position, varies by the addition method or the like, 5 to 1000 mg / l with respect to a mixture of 曝 <br/> gas tank, preferably suitably about 10 to 200 mg / l. The addition method may be continuous addition, but it is possible to add it for a predetermined time, for example, once a day.
A method of intermittently adding so that the above concentration is obtained at a rate of once is preferable. Further, when the bulking is slight, there are cases where only the first addition is required.

By adding the anionic or nonionic surfactant in this manner, the filamentous bacteria in the activated sludge contract in the sheath body, or are shed or lysed from the sheath body, or the sheath body. There is a phenomenon that the slab is cut and the bulking is suppressed. At this time, other bacteria in the activated sludge are not affected and the decomposition activity for organic matter is maintained.

When the foaming in the aeration tank becomes vigorous due to the addition of the surfactant, an antifoaming agent can be added to prevent the foaming. As the defoaming agent that can be used here,
Examples include silicone oil and polypropylene glycol. Even in this case, the bulking suppressing effect can be obtained.

[0013]

According to the present invention, any activated sludge treatment system can be used.
Since the anionic or nonionic surfactant was added to the mixed liquid in the aeration tank from the location of the above, the active sludge can be activated without harming bacteria other than filamentous bacteria and human livestock. Filamentous bulking of sludge can be suppressed.

[0014]

EXAMPLES Test examples and examples of the present invention will be described below. In each example,% is% by weight.

Test Example 1 In a 500 ml Sakaguchi flask, glucose 0.3 g /
1, sodium acetate 0.3 g / l, ammonium sulfate 0.1 g / l, potassium chloride 0.05 g / l, magnesium sulfate 0.05 g / l, calcium carbonate 0.02 g / l
1, monosodium phosphate 0.02 g / l, disodium phosphate 0.312 g / l, ferric chloride 0.0005 g /
l, 100 ml of pH 7.0 medium was added and inoculated with 1 platinum loop of filamentous bacterium Sphaerotilus natans.
The cells were cultured at 0 ° C for 3 days at 100 rpm. The culture was centrifuged at 12000 rpm for 15 minutes to collect the cells, and the cells were suspended in 0.05 M Tris-HCl buffer (pH 8.0) and fragmented with a homoblender to give a cell suspension. The suspension was diluted with 0.05 M Tris-HCl buffer to an optical density (OD ₆₆₀ ) of 1 at ₆₆₀ nm,
Add 50m of sodium dodecylbenzene sulfonate to this.
It was added so as to be g / l, and the mixture was allowed to stand at 30 ° C. for 60 minutes. At this time, OD ₆₆₀ decreased to 0.2. As a result of microscopic examination, Sphaerotilus natans was almost lysed, and only the pods remained.

Test Example 2 In Test Example 1, when polyoxyethylene nonylphenyl ether (HLB14) was added instead of sodium dodecylbenzenesulfonate, the same result was obtained.

Example 1 Filamentous bulking sludge (MLSS 2530 mg / l,
SV ₃₀ 76, SVI 300) was placed in a 1-liter beaker, and sodium dodecylbenzenesulfonate was added to the beaker at a rate of 50 mg / l once a day to allow artificial drainage to pass, and 1 liter / min at 25 ° C. It was ventilated and treated for wastewater. The artificial wastewater had a composition of 10% glucose, 10% peptone, 5% 1 potassium phosphate and 10% 1 sodium phosphate, and was adjusted to pH 7.0. The TOC load was 0.5 kg / m ³ · day. As a result, lysis of filamentous bacteria was observed 3 hours after the addition of sodium dodecylbenzenesulfonate, and filamentous bacteria were hardly found in the sludge after 3 days.

Example 2 The same result was obtained when polyoxyethylene nonylphenyl ether (HLB14) was added in place of sodium dodecylbenzenesulfonate in Example 1.

Example 3 Activated sludge having filamentous bulking caused by Sphaerotilus natanus (MLSS 2530 mg / l,
SV ₃₀ 76, SVI 300) 1 liter 2 l
Put it in a graduated cylinder with iter volume and add the surfactant shown in Table 1 to a concentration of 50 mg / l.
Aerated at iter / min. At this time, foaming is 800 ml
Once reached, a small amount of silicone antifoaming agent was added as necessary to lower the interface. The SV ₃₀ was measured after 3 hours.
At this time, SV ₃₀ in the control bulking sludge containing no chemicals was almost unchanged from that before the start of the experiment. As a result of microscopic observation, there was no change in Sphaerotilus natans in the control, but SV ₃₀ was decreased in the case where the surfactant was added, and Sphaerotilus natans was lysed, eluted from the sheath, or contracted in the sheath. Was there. Table 1 shows the SV ₃₀ after 3 hours.

[0020]

[Table 1]

[0021]

[Table 2]

From the above results, the addition of the anionic or nonionic surfactant damages the filamentous bacterium,
It can be seen that the filamentous bulking is suppressed.

Example 4 Activated sludge (MLSS) in which filamentous bacteria were not observed under a microscope
To 3290 mg / l), 100 mg / l or 800 mg / l of lauryl alcohol ethylene oxide 7 mol adduct (HLB14) was added, and a liquid containing peptone and glucose as carbon sources at a ratio of 1: 1 (weight ratio) was 290
The mixture was added so that the amount became mg / l, and aeration was performed to examine the change in TOC. The results are shown in Fig. 1. For comparison, 100 mg of quaternary ammonium salt benzalkonium chloride is used.
The results are also shown in FIG. 1 in the case of adding 1 / l or 800 mg / l.

From the results of FIG. 1, it can be seen that the TOC decrease rate (gradient of the graph) is hardly affected by the addition of the 7-mol adduct of lauryl alcohol ethylene oxide, and does not harm bacteria other than filamentous bacteria. . However, TOC of benzalkonium chloride tends to increase after 30 minutes, which is considered to be due to elution from bacteria.

[Brief description of drawings]

FIG. 1 is a graph showing changes in TOC in Example 4.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/12 C02F 3/28-3/34 BIOSIS / WPI (DIALOG)

Claims (10)

(57) [Claims] 1. An aeration tank from any place in the activated sludge treatment system.
A method for suppressing filamentous bulking, which comprises adding an anionic or nonionic surfactant to the mixed liquid inside . 2. An aeration tank for an activated sludge treatment system or its pre-treatment.
The anionic or nonionic surfactant.
The filamentous bulking according to claim 1, wherein
Suppression method. 3. A high-grade alcohol is used as the anionic surfactant.
Sulfate ester salt, higher alkyl ether sulfate ester
Salt, sulfated oil, sulfated fatty acid ester, sulfated olfi
, Alkyl benzene sulfonate, alkyl naphthale
Sulfonate, paraffin sulfonate, and higher grade
One or more selected from the group consisting of alcohol phosphates
3. A surfactant, which is a surfactant.
A method for suppressing bulky filamentous bulking. 4. The nonionic surfactant is HLB8-1.
8 higher alcohol ethylene oxide adduct, al
Killphenol ethylene oxide adduct, fatty acid ethyl
Oxide adduct, polyhydric alcohol fatty acid ester
Lenoxide adducts, ethylene oxide adducts of fats and oils,
Propylene glycol ethylene oxide adduct, glyceride
Roll fatty acid ester, pentaerythritol fat
Acid esters, sorbitol and sorbitan fatty acid
Stells, sucrose fatty acid esters, polyhydric alcohols
Rutile ethers and fatty acids of alkanolamines
One or more surfactants selected from the group consisting of amides
The filamentous bar according to claim 1 or 2, wherein
How to suppress luking. 5. An aeration tank from any place in the activated sludge treatment system.
Anionic or nonionic interface to the mixture in
The activator is added so as to be 5 to 1000 mg / L.
The method according to any one of claims 1 to 4, characterized in that
A method for suppressing filamentous bulking. 6. An aeration tank from any place in the activated sludge treatment system.
Anionic or nonionic interface to the mixture in
Special feature is to add antifoaming agent at the same time as or separately from activator.
The filamentous bar according to any one of claims 1 to 5, which is a characteristic.
Suppression method of Rukingu. 7. An aeration tank from any place in the activated sludge treatment system.
Inhibitor of filamentous bulking added to the mixture in
And including an anionic or nonionic surfactant.
Inhibitor of bulky filamentous bulking. 8. A higher alcohol sulfate ester salt, a higher alcohol
Lukyl ether sulfate, sulfated oil, sulfated fat
Acid ester, sulfated olefin, alkylbenzene sulfone
Phonate, alkylnaphthalene sulfonate, paraffin
Sulfonates and higher alcohol phosphates
Containing one or more anionic surfactants selected from the group
The filamentous bulking of claim 7, wherein
Inhibitor. 9. A higher alcohol which is HLB 8-18.
Tylene oxide adduct, alkylphenol ethylene oxide
Xide adduct, fatty acid ethylene oxide adduct, polyvalent adduct
Rucol fatty acid ester ethylene oxide adduct, oil and fat
Ethylene oxide adduct of propylene glycol
Renoxide adduct, fatty acid ester of glycerol,
Sorbitol, fatty acid ester of pentaerythritol
And fatty acid ester of sorbitan, fatty acid ester of sucrose
Stell, alkyl ethers of polyhydric alcohols, and
Selected from the group consisting of fatty acid amides of lucanolamines
Characterized in that it contains one or more nonionic surfactants
The inhibitor for filamentous bulking according to claim 7. 10. Anionic surfactant or nonion
8. A composition comprising a surface active agent and an antifoaming agent.
Suppression of filamentous bulking according to any one of 1 to 9
Agent.