JPH1133583A - Bulking controlling agent of activated sludge and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bulking controlling agent which prevent the generation of a bulking phenomenon without deterioration of water quality and without retarding the growth of useful flock-forming bacteria in activated sludge processing and a method for controlling bulking. SOLUTION: In a bulking control method of activated sludge, as effective components, at least one of a compound given by formula I, (in which n represents an integer of 0-6, when n is 2 or greater, R can be different from each other; R represents amino, a halogen, hydroxyl, sulfonate, and a 1-40C alkyl or alkenyl or its salt and, as required, a bulking controlling agent of activated sludge containing at least one of a cationic polymer flocculant, an inorganic flocculant, and a clay mineral are added into an aeration tank, a precipitation tank, or return sludge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bulking control agent for controlling bulking caused by filamentous microorganisms, which is the greatest obstacle in facility management, in an activated sludge method effective for treating organic matter-containing wastewater, and to use the same. It relates to a method for controlling bulking.

[0002]

2. Description of the Related Art Activated sludge is widely used as a method for treating organic-containing wastewater. However, it is said that the bulking phenomenon caused by activated sludge that has settled poorly is the biggest problem in the activated sludge process. I have. This is because
The growth balance of the microflora in the activated sludge is disrupted, and the filamentous microorganisms predominate over the floc-forming bacteria. Once bulking occurs, the activated sludge swells and becomes difficult to sediment, making it impossible to obtain an interface between the activated sludge and the treated water in the sedimentation tank, causing the activated sludge to run off and causing environmental pollution. I was Furthermore, the runoff of the activated sludge does not maintain the MLSS (suspended matter in the aeration tank mixture) concentration of the activated sludge in the aeration tank, and the biodegradation of the organic matter dissolved in the wastewater by the activated sludge becomes poor. This has caused even more environmental pollution.

When the bulking phenomenon occurs, it is common to add an inorganic flocculant or a polymer flocculant in order to increase the sedimentation of activated sludge, and these chemicals may be inexpensive. Therefore, it is frequently used in each wastewater treatment facility. Further, bulking is controlled by adding inexpensive bactericides such as chlorine to the aeration tank.

[0004]

The addition of a flocculant to the activated sludge treatment system temporarily solves the deterioration of the settling property of the activated sludge, but it is only a mere emergency treatment, and the removal of the filamentous microorganisms causing the bulking. It is not effective in preventing the recurrence of bulking because it does not control growth. In addition, since there is no selection system for bactericides such as chlorine, not only the growth of filamentous microorganisms causing bulking, but also the harmful effects on the growth of useful organisms of activated sludge, the water quality becomes extremely poor after bulking control. There has been a problem that it deteriorates and induces a recurrence of bulking due to the death of useful microorganisms. An object of the present invention is to provide a bulking controlling agent and a bulking controlling method for preventing the occurrence of a bulking phenomenon in activated sludge treatment without deteriorating water quality and without inhibiting the growth of useful floc-forming bacteria. It is in.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that a compound represented by the following general formula (I) (wherein n represents an integer of 0 to 6; In the formula, R may be different from each other, R is an amino group,
A halogen atom, a hydroxyl group, a sulfonic acid group, or an alkyl group which may have a C1-40 unsaturated group) or a salt thereof as an active ingredient; It has been found that the occurrence of the bulking phenomenon can be prevented, and the present invention has been completed.

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That is, in the present invention, as an active ingredient, a compound represented by the general formula (I) (wherein n represents an integer of 0 to 6, and when n is plural, Rs may be different from each other. R represents an amino group, a halogen atom, a hydroxyl group, a sulfonic acid group, an alkyl group which may have a C1 to 40 unsaturated group) or a salt thereof, and a bulking control agent for activated sludge, A bulking control agent for activated sludge containing at least one kind of the compound represented by the general formula (I) or a salt thereof and at least one kind of a cationic polymer flocculant or an inorganic flocculant, or a compound represented by the general formula (I) The present invention relates to a bulking control agent for activated sludge containing at least one kind of the compound or a salt thereof, at least one kind of cationic polymer flocculant or inorganic flocculant, and at least one kind of clay mineral. The present invention also relates to a method for controlling bulking of activated sludge, characterized by adding any of the above bulking controlling agents to an aeration tank, a sedimentation layer or returned sludge.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The bulking control agent according to the present invention is used in an activated sludge treatment system. Here, the activated sludge treatment system is a system for aerobically treating wastewater. In addition to the activated sludge method, all methods that are said to be variations thereof are included.

As described above, the bulking controlling agent according to the present invention includes, as an active ingredient, a compound represented by the general formula (I) (wherein n is an integer of 0 to 6; R may be different from each other, R may be an amino group, a halogen atom, a hydroxyl group, a sulfonic acid group, C1-40.
Or an alkyl group which may have an unsaturated group), or a bulking controlling agent for activated sludge containing at least one kind of a salt thereof, at least one kind of a compound represented by the general formula (I) or a salt thereof. Activated sludge bulking control agent containing at least one cationic polymer flocculant or inorganic flocculant, or at least one compound represented by formula (I) or a salt thereof and a cationic polymer flocculant Or at least one of inorganic coagulants and at least one of clay minerals
And a compound containing a compound represented by the general formula (I):
Although the bulking inhibitory effect can be sufficiently obtained by the addition of only the compound represented by, the initial sludge settling property immediately after the compound addition is improved by using the polymer flocculant, the inorganic flocculant, and the clay mineral together, and the bulking control A remarkable effect that the period lasts can be expected.

In the present invention, the substituent represented by R in the general formula (I) includes an amino group, chlorine, bromine, iodine,
C1-C40 such as halogen atoms such as fluorine, hydrogen groups, sulfonic acid groups, methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, ter-butyl groups, sec-butyl groups, allyl groups, and propargyl groups. Represents an alkyl group which may have one or more double bonds or triple bonds. In the case of a hydroxyl group or a sulfonic acid group, salts thereof are also included in the present compound. Examples of the salt include commonly used metals such as sodium, potassium and lithium. The number of substituents is 0
To 6, and when there are a plurality of substituents, the substituents may be different from each other. Specific examples of the compound include 1,2-
Naphthoquinone, 1,2-naphthoquinone-4-sodium sulfonate, 1,4-naphthoquinone, 2-amino-3-
Chloro-1,4-naphthoquinone, 2,3-dichloro-
1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, 5-hydroxy-1,4-naphthoquinone, 2-methyl-5-hydroxy-1,4-naphthoquinone, 5,8-dihydroxy-1,4-naphthoquinone, vitamin K1 and the like can be mentioned. These compounds can be used alone or in combination of several kinds.

In the present invention, examples of the cationic polymer flocculant include polyacrylate, polymethacrylate, vinylformamide, polyacrylamide, polyamine and dicyandiamide polymer flocculants. it can. Examples of the inorganic coagulant include aluminum sulfate and ferric chloride, and examples of the clay mineral include sepiolite, vermiculite, and attapulgite.

The above-mentioned bulking agent can be added to any place in the activated sludge treatment system, but the addition to the aeration tank is most effective in suppressing bulking. As a method of adding to the aeration tank, a method of adding continuously or a method of adding twice or three times per day can be considered, and any method can be freely selected. Also, depending on the degree of bulking,
A sufficient suppression of bulking can be expected with only one addition. Further, prior to the addition, there is no need to change the operation management method of the facility on a daily basis, such as adjusting the pH or the aeration intensity, and the effect of suppressing bulking can be obtained under very simple addition conditions.

The compound represented by the general formula (I) is usually
Although used as a powder, it can be dissolved in water or the like and used as a liquid agent. When a powder is used, the above compound is used in an amount of about 1 to 200 mg / l, preferably
By adding about 50 mg / l, the growth of filamentous microorganisms that cause bulking can be suppressed. Further, when activated sludge is flowing out of the settling tank, it can be used by mixing with one or more of clay mineral, cationic polymer flocculant or inorganic flocculant. The amount of the clay mineral and the inorganic coagulant is about 10 to 200 mg / l, and the amount of the polymer coagulant is about 1 to 50 mg / l, preferably about 10 to 20 mg / l, based on the total volume of the aeration tank. Is appropriate.

When the bulking control agent of the present invention is added,
Improvement of sedimentation of sludge, decrease in the growth number of filamentous microorganisms in activated sludge, cutting and bending of filamentous filamentous microorganisms,
Twist and the like can be observed several days after the addition. Moreover, at this time, no adverse effects on the growth of useful microorganisms and protozoa forming flocs are observed, so that good water quality can be obtained. Thus, according to the present invention,
It is possible to control bulking while obtaining good water quality without adversely affecting activated sludge.

[0014]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the technical scope of the present invention is not limited to these examples. (Generation of bulking) Aeration tank (21) and sedimentation tank (0.5)
In the culture device from which 1) is separated, artificially synthesized wastewater (glucose 870 mg / l, peptone 250 mg / l, sodium chloride 300 mg / l, dipotassium phosphate 39 mg / l)
l, ammonium nitrate 43 mg / l) was continuously supplied, and the activated sludge was cultured. 1 l / day of synthetic wastewater inflow,
Filamentous bulking was generated under the conditions of MLSS concentration of 2,000 mg / l and room temperature of 20 to 25 ° C., and the following experiment was performed. The filamentous microorganisms generated at this time were TY.
PE021N, Spherothylus natansu, TYPE1
701 and TYPE 1702. (Eikelbo
omD. H. Filamentous organi
sms observed in activated
sludge. Water Research vo
l. 9: 365-388 (1975), the filamentous microorganisms were identified. ).

(Judgment of bulking suppression effect) Judgment of bulking suppression effect is carried out for 3 hours (180 minutes)
Sedimentation of activated sludge when settled (expressed as SV180),
Judgment of the growth of filamentous microorganisms by microscopic observation (very much = ++++++++ ±± very little), p of aeration tank
H, turbidity of treated water (cloudy = +, transparent =
-), The effect on the protozoan population (affected = present, no effect = none).

(Examples 1 to 8) Compounds shown in Examples of Table 1 were applied twice to activated sludge, in which bulking was caused by filamentous microorganisms, at a rate of 10 mg / l.times. Was added. After the addition, continuous culture was continued, and the effect of suppressing bulking was determined on the fourth day from the start of the test. A control without any addition was used as a control. As a result, the sludge settling property of the control plot was SV180 = 94%, but in the compound-added plots of the examples, the sludge sedimentation property was improved, and the number of filamentous microorganisms grown was also reduced. The pH of the aeration tank water was almost the same as that of the control group, no turbidity was observed in the settling tank, and the number of protozoa was not reduced.

[0017]

[Table 1]

[0018]

By adding the bulking control agent of the present invention to an aeration tank, the number of filamentous microorganisms that can grow can be reduced without adversely affecting the growth of useful microorganisms forming flocs. As a result, the sedimentation of the sludge is greatly improved.

Claims (4)

[Claims] 1. A bulking control agent for activated sludge, characterized by containing at least one compound represented by the general formula (I) or a salt thereof as an active ingredient. (In the formula, n represents an integer of 0 to 6, and when n is plural, Rs may be different from each other. R represents an amino group, a halogen atom, a hydroxyl group, a sulfonic acid group, a C1 to 40 unsaturated group. Represents an alkyl group which may be present) 2. Activated sludge comprising as an active ingredient at least one compound represented by the general formula (I) or a salt thereof and at least one cationic polymer flocculant or inorganic flocculant. Bulking control agent 3. A compound represented by the general formula (I) or at least one salt thereof, at least one cationic polymer flocculant or inorganic flocculant, and at least one clay mineral.
Activated sludge bulking controlling agent characterized by containing seeds as an active ingredient 4. A method for controlling bulking of activated sludge, which comprises adding the bulking control agent according to claim 1 to an aeration tank, a sedimentation layer, or returned sludge.