JPH03127694A - Abnormal phenomenon preventive agent for activated sludge and method for preventing abnormal phenomenon of activated sludge - Google Patents

Abstract

PURPOSE:To exterminate the actinomycetes to be the cause for bulking, etc., by using the reaction product of amine and diepoxide or the amine and the diepoxide and epihalohydrin, etc. CONSTITUTION:The amine and the diepoxide or the amine and the diepoxide and the epihalohydrin and/or alkylene dihalide are brought into reaction to synthesize the water soluble polymer. This water soluble polymer is added to the activated sludge contg. the filamentaous bacteria or actinomycetes or the waste water contg. the activated sludge at 0.05 to 25 pts.wt. per 100 pts.wt. dry solid content of the activated sludge, by which the abnormal phenomenon of the activated sludge is prevented. The ultimate viscosity [eta] of the above mentioned water soluble polymer is adequately 0.02 to 0.4dl/g (25 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention deals with the swelling phenomenon of activated sludge, that is, bulking.
The present invention relates to an agent for preventing abnormal phenomena such as the formation of a foam layer and scum formation in the upper part of an aeration tank or settling tank that occurs during aeration treatment of activated sludge, and a method for preventing abnormal phenomena.

[Conventional technology]

Activated sludge method is one of the biological methods used for wastewater treatment. This method involves blowing air into wastewater containing organic matter to propagate microorganisms, thereby removing the sludge and
In other words, it utilizes the properties of activated sludge, and since activated sludge produces flocs rich in vJtrI properties, and the specific gravity of the flocs is greater than that of water (for example, it is said to be around 1.003), it is difficult to leave it still. This method takes advantage of the phenomenon in which clear treated water is left behind after sedimentation. The settled activated sludge is reused as return sludge.

Sewage, human waste and various organic industrial wastewaters are commonly treated with activated sludge. During treatment using this method, changes occur in the flow rate of inflowing wastewater, changes in organic matter in inflowing wastewater, and changes in the types of microorganisms such as various molds, filamentous bacteria, and actinobacteria that grow in sewer pipes. It is known that the microbial flora in activated sludge changes in response to these changes.

For example, when the solid content in the influent raw water is low and the sludge retention time (SiI2) is high, Nocardia.

Nocardia aware grows in large numbers in activated sludge, produces surface-active mycolic acid, promotes bubble stabilization, and causes sludge-containing bubbles to remain in the upper part of the aeration tank and final settling tank. It is accumulated and released. The effluent itself may also foam, damaging its appearance. Also filamentous bacteria,
When actinomycetes are added to the sludge, the sludge swells and settles poorly.
The sludge rises to near the water surface, the amount of sludge overflowing increases, the treatment capacity decreases, and in some cases, the so-called bulking phenomenon occurs, where treatment becomes impossible. When this phenomenon occurs, the sludge becomes whitish, very light, and difficult to settle, and it also has air bubbles attached to it, and the foaming tank with sludge attached to the top of the aeration tank sometimes extends over several tens of centimeters. It also reaches and accumulates. Moreover, the sludge that adheres to the air bubbles accumulated at the top of the aeration tank or the sludge that adheres to the air bubbles that overflow from the aeration tank rots and gives off a bad odor, and the sludge in the air bubbles that accumulates in the aeration tank eventually settles. If the treated water is discharged from the tank together with the treated water, the treated water may have a poor appearance due to foaming, and BOD and CO[) may rise to the top, causing environmental sludge.

One indicator of whether activated sludge is functioning properly is the SVI (Sludge Volume Index).
, sludge index) values. This SVI is expressed as the volume occupied by 1 g of activated sludge in 30 minutes of settling. The svi4g of activated sludge that exhibits normal functions is 50 to 150.
In particular, it is less than 100, but that of activated sludge that has undergone bulking can be as high as 300 to 800. Furthermore, the increase in SVI value caused by actinomycetes is 200 to 3008 degrees, and this may cause sewage outflow due to the rise of the sludge interface.

It is not easy to restore the function of activated sludge that has generated foaming, scum, or bulking, and in the worst case, it becomes necessary to replace the sludge. It would be necessary to stop using the product until the product has become accustomed to the product, which would have a serious impact on the factory's production plan.

Even in public sewage treatment plants, the BOD removal efficiency decreases due to the outflow of expanded sludge and a decrease in sludge concentration, which can lead to environmental pollution and become a major social problem.

Methods for preventing bulking of activated sludge are disclosed in Japanese Patent Publication No. 58-14274 and Japanese Patent Publication No. 58-14275.
The method described in the above publication has been proposed.

The method described in Japanese Patent Publication No. 58-14274 is a method in which 11 or more types of dithiocarbamates having a specific structure are dissolved in water and added to activated sludge. However, this method is intended only when the cause of bulking is abnormal proliferation of filamentous WM4, and is not effective when there are other causes.

In addition, when using this method, it takes more than 4 days, and in some cases more than 10 days, for the activated sludge to become effective, even if the degree of damage to the activated sludge is relatively minor, and in addition, a large amount is added every day. The downside is that you have to keep going.

The method described in Japanese Patent Publication No. Sho 58-14275 involves the addition of ti or 2 amino acids such as valine, leucine, isoleucine, glutamic acid, phenylalanine, and tyrosine to wastewater.
A composition containing at least one species as an active ingredient is added to activated sludge. When using this method, a composition containing these active ingredients is added to the influent wastewater at a rate of 0.
It needs to be added continuously for more than 3 hours at a level as high as 5-5Kg/m'', and it takes 24 hours for it to be effective.
It has the disadvantage that it requires more time.

The bulking phenomenon of activated sludge is caused by 5phaerot[1u
s (Sphaerotilus spp.), Th1othrix (
In addition to preventing the abnormal growth of filamentous bacteria and fungi such as Thiothrhynchus (genus Thiothorhynchus), ^spergillus (genus Aspergillus), and Penicillium (Penicillium N), highly viscous jelly-like substances may form in activated sludge depending on the season and nutritional status. This causes the sludge to become difficult to settle and may exhibit a bulking phenomenon. In the latter case, it is said to be effective to add ZnCIg or a cationic acrylamide polymer flocculant to the wastewater. However, according to experiments conducted by the present inventors, this method has shown that activated sludge tends to contain air bubbles in aeration tanks, etc. (activated sludge containing air bubbles has an extremely reduced ability to treat wastewater, and prevents bulking from occurring. It was found that there was no significant effect.

In addition, attempts have been made to restore the normal microbial flora without relying on the addition of chemicals, for example, using only operating conditions such as adding a large amount of suspended solids (SS) without using anaerobic or aerobic treatment or an initial settling tank. However, type 021N, type 1701. Type 1702. Type 004! No satisfactory method has yet been proposed for bulking caused by the overgrowth of at least one type of filamentous bacteria such as Structylinus and Parvicella.

In addition, to prevent foaming, scum, and bulking caused by actinomycetes, a method is known in which an antifoaming agent, such as a carboxylic acid ester compound, is mixed with shower water and sprayed in the aeration tank and final settling tank. According to an experiment conducted by the present inventor, it was found that this method of mixing and spraying an antifoaming agent does not suppress foaming, but only destroys the bubble tank that is formed, and has almost no effect.

In general final treatment plants for urban sewage, most bulking occurs due to filamentous bacteria, and Sphherotilus and Begglatoa have traditionally been considered to be representative microorganisms that cause this (according to the Japan Sewage Works Association). Magazine, Vol. 22, No. 252, pp. 2-12 (198
By the way, with the recent sewerage 518,
As rainwater and domestic wastewater, etc., have come to be treated separately, changes have also occurred in the filamentous bacteria that cause bulking when urban sewage, which is domestic wastewater, is treated using the activated sludge method. Presumed.

[Problem to be solved by the invention]

In response to recent changes in urban sewage, the present invention is designed to prevent specific filamentous bacteria that cause abnormal phenomena such as bulking, or to form a foam layer on the top of an aeration tank or settling tank during aeration treatment of activated sludge. , to provide an agent for preventing abnormal phenomena in activated sludge made of a specific water-soluble polymer and a method for preventing the same, with the aim of specifically killing actinomycetes that cause scum and bulking! This is the subject.

(!!Means for solving l1tl) That is, the activated sludge abnormal phenomenon prevention agent of the present invention is an agent for preventing the activated sludge bulking phenomenon caused by at least III filamentous bacteria or the activated sludge abnormal phenomenon caused by actinomycetes. It is characterized in that it consists of a water-soluble polymer obtained by reacting an amine with a geboxide, or an amine with a dieboxide and an epihalohydrin and/or an alkylene dihalide.

Further, the method for preventing abnormal phenomena in activated sludge of the present invention includes adding amine and geboxide, or agon and geboxide, and epihalohydrin and activated sludge containing at least one type of filamentous bacteria or actinomycetes to activated sludge or activated sludge-containing wastewater. It is characterized in that 0.05 to 25 parts by weight of a water-soluble polymer obtained by reaction with/or an alkylene dihalide is added to 100 parts by weight of dry solid content of activated sludge.

[Target activated sludge]

Activated sludge targeted by the anti-bulking agent of the present invention is subjected to bulking by at least one type of filamentous bacteria from the group consisting of type 021N, type 1701, type 1702, type 0.041, Microsliph, and Parvicella, or actinomycetes. It is something that causes

Type 021N, Type 0041, and Electrical Crosslink.

Parvicella filamentous bacteria are 0. H, Eil@lboo
m: Prog.

14ater Tech, + Volume 8, No. 6, No. 1
53-161 (1977). Also, type 1? The filamentous bacteria of OL type 1702 are P, F, Storm and El, Jenktns.
: Journal 14PcF, No. 56j8, No. 5
No. 499-459 (191114). If these filamentous bacteria need to be isolated, they can be easily obtained from activated sludge of sewage.

The abnormal phenomenon prevention agent of the present invention is applied to activated sludge that has signs of bulking caused by these filamentous bacteria, or that has undergone bulking, or wastewater containing activated sludge.

Further, the abnormal phenomenon prevention agent of the present invention is intended for activated sludge that causes foaming, scum, or bulking in treated water after sedimentation due to actinomycetes. Actinomycetes in activated sludge etc. include Nocardia and Amarae.
rhia aware), Rhodococus rhodochrous (Rhodococcus rhodochrous)
etc. If it is necessary to isolate such actinomycetes, they can be easily obtained from the foam tank, scum, and sludge accumulated in the upper layer of the aeration tank of activated sludge from sewage.

[Water-soluble polymer]

The abnormal phenomenon preventive agent of the present invention comprises amine and diepoxide,
Or it is a water-soluble polymer obtained by reacting an amine with a dieboxide and an epihalohydrin and/or an alkylene dihalide.

In addition, in water-soluble cationic polymers obtained by the reaction of secondary amines with diepoxides, epihalohydrins and σ/alkylene dihalides, counterions (halogens derived from epihalohydrin and alkylene dihalides) are combined with other anions. and the corresponding hydroxides.

The amine, which is a raw material for such a polymer, is an old 2 (Rt, Rt, Ri and R1 are hydrogen or carbon number 1
~3 straight chain or branched alkyl group, A is a straight chain or branched alkylene group having 1 to 6 carbon atoms, n is 0 to
(an integer of 5) is represented by the general formula (B is absent, or is a linear or branched alkylene group having 1 to 4 carbon atoms, or -(CH wealth OCHz
) x (ether compound represented by X is 1 to 4); as epihalohydrins, those represented by the general formula %); and as alkylene dihalides, those represented by the general formula (C is 1 to 20 linear or branched alkylene groups (X is halogen) are suitable.

Specific examples of such amines include ammonia, methylamine, dimethylamine, diethylamine, dipropylamine, methylethylamine, methylpropylamine, ethylpropylamine, etc. for monoalkylamines (n=o); Boriaton (n=
In 1), ethylenediamine, N,N-dimethylethylenediamine, N,N'-dimethylethylenediamine, N,N-diethylethylenediamine, propylenediamine/N,N-dimethylpropylene cyano, N,N
.

These agents can be used in combination within or between the above groups.

Examples of the diepoxide include 1.3-butadiene diepoxide, 1.4-pentadiene diepoxide, and 1.5-butadiene diepoxide.
-hexadiene diepoxide, 1,6-hebutadiene diepoxide, 1,7-octazidine dieboxide, ethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, and the like.

The epihalohydrin is generally one in which the halogen is fluorine, chlorine, bromine or iodine, and epichlorohydrin is preferred for economic reasons.

Examples of the alkylene dihalide include dichloroethane, dichloropropane, dichlorobutane, dichlorohexane, dibromoethane, bromochloropropane, dibromopropane, dibromohexane, dichlorononane, and the like. Especially 1,2-dichloroethane (ethylene dichloride)
is preferred for economic reasons.

Dieboxide, epihalohydrin, and alkylene dihalide may be used alone or in combination of two or more of them for each component, and when mixing epihalohydrin and/or alkylene dihalide with dieboxide, the mixing ratio should be determined according to the mixture. There is no particular limitation as long as the sum of the moles is approximately equivalent to that of the amine.

To react an amine and a dieboxide, or an amine and a dieboxide and an epihalohydrin and/or an alkylene dihalide, the sum of the number of moles of the amine and the number of moles of the dieboxide, or the number of moles of a mixture of dieboxide, epihalohydrin, and/or alkylene dihalide is used. Using a closed reaction vessel with a stirrer, the temperature inside the reaction vessel was set to 30 to 100°C under an inert gas atmosphere.
It is better to set [[l.

More specifically, a 20 to 70% aqueous solution of Aju is charged into a closed reaction container equipped with a stirrer, a reflux condenser, a thermometer, etc., and the atmosphere inside the container is replaced with nitrogen. The dieboxide or the dieboxide, epihalohydrin and/or alkylene dihalide mixture may be added continuously or batchwise while stirring and adjusting the temperature inside the reaction vessel to a predetermined temperature.

Water is mainly used as the solvent during the reaction, but methyl alcohol, ethyl alcohol, dimethylformamide, etc. may also be used in consideration of the solubility of the raw materials and reaction products.

The water-soluble polymer thus obtained is further processed,
The halogen (derived from dihalogenoethyl ether) as a counterion may be replaced by another anion, or the counterion may be removed to form the polymer into a hydroxide.

The molecular weight of the water-soluble polymer thus obtained can be determined by its intrinsic viscosity [η] at 25°C, which is measured by dissolving it in a 2 mol/e KBr aqueous solution. In the present invention, [η] is preferably 0.4 dl/g or less and 0.102 dl/g or more, more preferably 0.3 dl/g or less. If (η) exceeds 0.4 dl/g, Activated sludge is filamentous III
rIi, enveloping actinomycetes and forming large flocs,
- The settling properties of sludge only improve over time, but foaming and scum will occur again after a few days, which is undesirable.
If it is less than 0.02 dl/g, the adsorption to activated sludge will decrease and the durability of the activated sludge's effect of preventing abnormal phenomena will decrease, which is not preferable.

The water-soluble polymer thus obtained can also be made into a solid by removing the solvent (usually water).

However, it is preferable to use the aqueous solution produced as it is, or after diluting or concentrating it if necessary.

(Method for preventing abnormal phenomena in activated sludge) The target activated sludge in which abnormal phenomena should be prevented contains the above-mentioned actinomycetes and specific filamentous bacteria. The method of preventing abnormal phenomena in activated sludge by adding chemicals according to the invention is the same as the conventional method.

Specifically, the water-soluble polymer is added to an appropriate concentration, for example 0.1 to
It is preferable to prepare an aqueous solution having a concentration of 10% by weight, and add this aqueous solution according to any of the following methods or a combination of 211 or more of these methods.

■ A method of mixing with the inflowing wastewater and sending it to the aeration tank.

■ Method of adding directly to an aeration tank or settling tank where bulking or foaming of activated sludge is occurring.

■ Method of adding to returned sludge.

If the amount of this water-soluble polymer used is too small, the purpose of the present invention will be impaired! On the other hand, if the amount is too high, the actinomycetes and filamentous bacteria will be rapidly destroyed and the treated water will suddenly become cloudy, or they will be flushed out of the system along with the wastewater, which may increase the COD of the treated water, so this is preferable. No, the amount used is 100% of the dry solid content of activated sludge! is preferably selected in the range of 0.05 to 25 parts by weight. More preferably, it is in the range of 0.1 to 10 parts by weight.

When a water-soluble polymer is added once within the above range to activated sludge, no increase in the SVI value is observed for one month or more.After that, if signs of an increase in the SVI value are observed, at that point the water-soluble polymer is added. It is preferable to add the polymer within the above range.

[Action and effect of invention]

As described above, according to the present invention, it is possible to specifically prevent bulking of activated sludge caused by at least one type of filamentous bacteria and abnormal phenomena of activated sludge caused by actinomycetes. That is, according to the water-soluble polymer according to the present invention, the water-soluble polymer is removed at the time when signs of an increase in the SVI value or foaming phenomenon are observed due to abnormal proliferation of filamentous bacteria or actinomycetes, or at the time when the SVI value is increased. Upon addition of the polymer, 5vI (
SVI without causing a substantial further increase in a.
Values can be kept at their original level or below. In addition, the foaming phenomenon is quickly resolved, and the good condition can be maintained.

Especially for filamentous bacteria, the filamentous form is destroyed,
Although the product is discharged from the treatment tank together with the treated water, almost no increase in BOD is observed, so it is possible to provide good treated water.Also, since the agent of the present invention lasts for a long time with one addition, The present invention is extremely useful in managing activated sludge processes.

In addition to these effects, the present invention also has the following effects.

(2) Simply adding it to the activated sludge treatment system can suppress the increase in SVI in a short time.

(2) The activated sludge in the aeration tank does not expand, reducing the sedimentation volume, keeping the activated sludge concentration high, and significantly increasing the BOD removal effect.

(2) Sedimentation and separation of activated sludge becomes extremely easy even in a settling tank.

(2) The concentration rate of activated sludge becomes significantly higher even in the thickening tank.

The water-soluble polymer of the present invention has a remarkable effect on destroying specific filamentous bacteria and actinomycetes in activated sludge, as well as preventing abnormal phenomena such as bulking of activated sludge caused by them. This is what I found.

Hereinafter, the present invention will be specifically explained with reference to Examples.

The case where the activated sludge contains filamentous bacteria according to Examples 1 to 4 and Comparative Examples 1 and 2, and the case where the activated sludge contains actinomycetes according to Examples 5 to 8 and Comparative Example 3 will be described.

[Example 1] Monthly average 6,500m'/day, BO [l is 200vag/
At a public sewage treatment plant that processes 100,000 liters of separated urban sewage wastewater, the settled sludge volume index (5VI) of the aeration tank is 60.
exceeds 0, and the dry sludge concentration (+1Lss) of returned sludge is 3
000mg/l or less, flLss of the aeration tank is also 2
000 mg/1 or less, and the separability of treated water and sludge in the Jil Hiiragi sedimentation tank deteriorated significantly.

When the sludge in the aeration tank and settling tank at this treatment plant was observed using a phase contrast microscope, and when it was stained with Durham and observed using an optical microscope, it was found that there were filamentous types of type 021N rather than floc-forming bacteria between the flocs. A larger volume of bacteria was observed.

The sludge from this public treatment plant is treated as if it were an actual public treatment plant.
Place it in a small model of activated sludge treatment with an aeration tank capacity of 31 liters and a settling tank capacity of 1 liter, and increase the dissolved oxygen in the aeration tank to 1 to 2 a+
g/l and convert the inflow raw water of the above public treatment plant into BO.
It was continuously added so that the D load was about 0.14 Kg/Kg MLSS/day, and the return sludge rate was set to 50%, and the operation was continued.

The molar ratio of 30% dimethylamine aqueous solution and ethylene glycol diglycidyl ether was adjusted to a ratio of 1=1.
A mixed reaction & [I acid (Fi
0.8 g of a composition having a limiting viscosity [η] of 0.08 dl/g was diluted 100 times with tap water and continuously added to the return sludge line in the small model for 48 hours.

The SVt of the sludge in the aeration tank and the COO of the treated water were measured 1 day, 3 days, 10 days, 20 days, and 30 days after the start of the reaction mixture and continuous addition of the Il precepts.

The results are shown in Figure 1.

[Example 2] The activated sludge containing type 021N filamentous bacteria from Example 1 was placed in a small model of activated sludge treatment similar to Example 1, and the amount of dissolved oxygen in the aeration tank as described in Example 1 was measured. i! under the same conditions as the inflow raw water addition amount and sludge return rate. I continued driving.

A 50% aqueous solution of methylamine-N,N,N',N'-tetramethylethylene cyanide mixture prepared in advance at a molar ratio of 1:0.5 and a molar ratio of l:l. Add a mixture of ethylene glycol diglycidyl ether and epichlorohydrin to a 50% aqueous solution of amine mixture while maintaining the reaction temperature at 90°C until the molar ratio of the mixture of ethylene glycol diglycidyl ether and epichlorohydrin adjusted to tit becomes tit. , the mixed reaction composition obtained by stirring and mixing (intrinsic viscosity [η] is Q
, 15 dl/g of the composition) was diluted 100 times with tap water and continuously added to the return sludge line in the small model for 48 hours.

1 day, 3 days after the start of continuous addition of the reaction mixture composition, 1
After 0 days, 20 days, and 30 days, foaming scum slippage at the aeration tank interface, SVI of sludge in the aeration tank, and CO of the treated water were observed.
O was measured in the same manner as in Example 1.

The results are shown in Figure 1.

[Example 3] Monthly average 14,000m'/day, BOD 2305g/
At a public sewage plant that processes 100 m of separated urban sewerage wastewater, the settled sludge volume index (SVr) of the aeration tank exceeds 400, and the dry sludge concentration (LSS) of returned sludge exceeds 3000.
mg71 or less, and the MLSS of the aeration tank is also 2000m.
gI became less than 1, and the separability of treated water and sludge in the final settling tank improved significantly. When the sludge in the aeration tank and settling tank at this treatment plant was observed using a phase-contrast W4 microscope and an optical microscope with Durham staining, it was found that there were more flocs than floc-forming bacteria between the flocs in the sludge. Many filamentous III bacteria of Type 1702, Type 0041, Microthrix, and Barbicella were observed.

This activated sludge was placed in a small activated sludge treatment model similar to that in Example 1, and continuous operation was performed under the same conditions as the amount of dissolved oxygen in the aeration tank, the amount of added raw water added, and the sludge return rate described in Example 1. did.

A 40% aqueous solution of a methylamine-dimethylamine mixture whose molar ratio was adjusted in advance to a ratio of 1:0.5, and a mixture of 1,7-octazidine dieboxide and ethylene dichloride whose molar ratio was adjusted in advance to a ratio of 1:1. 1.7 in a 40% aqueous solution of the amine mixture until the molar ratio is 11.
- A mixture of octazine diepoxide and ethylene dichloride is added, stirred and mixed while maintaining the reaction temperature at 85°C, and the resulting reaction mixture composition (composition with an intrinsic viscosity [η] of 0°11 dl/g) ) 1.2 g was diluted 100 times with tap water and continuously added to the return sludge line in the small model for 48 hours.

The SVI of the sludge in the aeration tank and the COD of the treated water were measured in the same manner as in Example 1 from the start of the continuous addition of the mixed reaction & [I acid.

The results are shown in Figure 1.

[Example 4] Type 17OL type 1702 of Example 3, type o0
Activated sludge in which 41, Microshrynx, and Barbicella are present is placed in a small model of activated sludge treatment similar to Example 1, and the amount of dissolved oxygen in the aeration tank described in Example 1, the amount of added raw water inflow, and Continuous operation was performed under the same conditions as the sludge return rate.

A 40% aqueous solution of a mixture of methylalone and dimethylamine prepared in a molar ratio of 1:1 in advance and a molar ratio of 1:1 in advance.
: 1,7-octazidine diepoxide adjusted to 1,
40% of the amine mixture until the molar ratio of epichlorohydrin and ethylene dichloride mixture is 1:1.
% aqueous solution of 1.7-octashiene dieboxide-ebichlorohydrin-ethylene dichloride mixture,
Stir and mix, and while diluting 1.0 g of the resulting reaction mixture &II (&11 product with an intrinsic viscosity [η] of 0°08 dl/g) 100 times with tap water, return the sludge in the above small horizontal type. It was continuously added to the line for 48 hours.

From the start of continuous addition of the mixed reaction composition, the SVI of the sludge in the aeration tank and the COO of the treated water were measured in the same manner as in Example 1.

The results are shown in Figure 1.

[Comparative Example 1] Using the same activated sludge and operating conditions as in Example 1, a sodium hypochlorite aqueous solution (available chlorine concentration 5%) was added to the return sludge line in place of the reaction mixture composition in the present invention at a concentration of 0. 8
When added at a rate of 0.8 g/day for 7 days, the filamentous bacteria contained in the sludge began to decrease, but the SVI value was 370, which was still not sufficient. Added for days.

From the start of continuous addition of sodium hypochlorite, the SVI of the sludge in the aeration tank and the COO of the treated water were measured in the same manner as in Example 1.

The results are shown in Figure 1.

[Comparative Example 2] Using the same activated sludge and operating conditions as in Example 2, cationic polyacrylic acid (Clifix CP627 manufactured by Kurita Water Industries, Ltd.) was used instead of the reaction &1ltc product of the present invention.
When added to the return sludge line at a rate of 0.2 g/day to the sludge in the aeration tank for 3 consecutive days, the SVI value reached 140 in a state containing filamentous bacteria.

However, after the addition was stopped, the settling property gradually worsened, and after 5 days, the VI was 360, so the addition was continued for 3 days at a rate of 0.2 g/day.

From the start of continuous addition of cationic polyacrylic oxide, the SVI in the aeration tank and the COO of the treated water were
was measured.

The results are shown in Figure 1.

11th! 1 and microscopic observation of the activated sludge in the aeration tank revealed the following.

(2) In Comparative Example 1, the addition of sodium hypochlorite destroyed not only filamentous bacteria but also useful floc-forming bacteria, making the treated water extremely cloudy.

In Comparative Example 2, the SVI value of the activated sludge temporarily decreased due to the addition of cationic polyacrylic oxide, but when the addition was stopped, the SVI value of the activated sludge increased again, and when the addition was repeated, the SVI value of the activated sludge increased again. In the tank, the sludge trapped air bubbles and floated to the surface, resulting in poor conditions.

According to the present invention, it was found that the amount of added chemicals was small compared to the comparative example, the 5Vl value was reduced quickly, the sedimentation property of activated sludge was significantly improved, and the effect was long lasting.

(2) When the present invention is used, the filamentous bacteria in the sludge present in the aeration tank and settling tank are extremely reduced compared to each comparative example, and the activated sludge forms solid flocs.

(2) When the present invention is used, the filamentous bacteria are destroyed and flow out, but the treated water has a C0D (l = 20-g)2 or less and is good as treated water.

[Example 5] Monthly average 5. Goos” 7 days, aOO 200mg/1
In a public sewage plant that processes separated urban sewerage wastewater with a suspended solid content <SS> of 120 ag/j, the settled sludge volume index (SVt) of the aeration tank is around 250, but it emits a unique odor. At the top of the aeration tank, about 10 to 20 cm of sludge had been trapped in the foam tank, which had turned brown, and remained there forever.Moreover, this foam layer overflowed from the top of the aeration tank, and the surrounding area The overflow may rot and become a source of bad odors, and to make matters worse, the foam layer containing sludge flows into the final settling tank and flows out with the treated water, causing ROD and COD in the effluent water. The dry sludge concentration of returned sludge from this treatment plant <+ILsS) was 3500 mg/l.
1. MLSS in the aeration tank was 100mg/1.

When the sludge from the aeration tank and settled RPs at this treatment plant was Durham stained and observed using an optical W4 microscope, many typical actinomycetes attached to flonk-forming bacteria were observed in the periphery of the sludge. Ta. The sludge contained actinomycetes, and the sludge adhered to the ξcholic acid secreted by actinomycetes and its filamentous forms, reducing the density of the sludge and making it difficult to settle.

The sludge from this public sewage treatment plant was put into a small activated sludge treatment model with an aeration tank capacity of 31 and a sedimentation tank capacity of 11, assuming an actual public sewage treatment plant, and the amount of dissolved oxygen in the aeration tank was reduced to 1.
Adjust the inflow raw water of the above public sewage treatment plant to ~2ag/j so that the 800 load is about 0°4 Kg/Kg MLSS/day! ! The sludge was added continuously, and the return sludge ratio was set to 25% for continuous operation.

The mixed reaction prepared in Example 1 has a limiting viscosity [η
] is 0°08 dl/g) 1. While diluting Og 100 times with tap water, it was continuously added to the return sludge line of the small model.

The reaction mixture composition is added to i! One day, three days, ten days, twenty days, and thirty days after the start of the continuous addition, the amount of foamed scum at the aeration tank interface, the SVI of the sludge in the aeration tank, and the COO of the treated water were measured. However, the amount of foamed scum at the interface of the aeration tank is expressed as a percentage of the foamed scum accumulated before the start of continuous addition of the above reaction mixture composition, that is, the volume of foamed scum before the start of continuous addition is taken as 100%. .

The results are shown in Figure 2.

[Example 6] The activated sludge containing actinomycetes from Example 5 was placed in a small model of the same activated sludge treatment as in Example 5, and the amount of dissolved oxygen in the aeration tank and the inflow raw water as described in Example 5 were measured. The system was operated under the same conditions as the addition amount and activated sludge return rate.

While diluting the reaction mixture composition prepared in Example 2 (1.2 g of the &Il potent acid having an I limiting viscosity [η] of 0.15 dl/g) with tap water, the return sludge line in the small model was diluted 100 times with tap water. was continuously added for 48 hours.

The above reaction mixture composition was added once a day from the start of continuous addition.
After 3, 10, 20, and 30 days, the amount of foamed scum at the aeration tank interface, the SVI of the sludge in the aeration tank, and the COD of the treated water were measured in the same manner as in Example 4.

The results are shown in Figure 2.

[Example 7] The activated sludge containing actinomycetes in Example 5 was placed in the same small model as in Example 5, and the amount of dissolved oxygen in the aeration tank, the amount of added raw water, and the activity described in Example 5 were measured. Continuous operation was performed under the same conditions as the sludge return rate.

While diluting 1.0 g of the reaction mixture composition prepared in Example 3 (intrinsic viscosity [η] of 0.18 dl/g with tap water) to the return sludge line in the small model, It was added continuously for hours.

The amount of foamed scum at the aeration tank interface from the start of continuous addition of the mixed reaction composition, the SVI of the sludge in the aeration tank, and the COD of the treated water were measured in the same manner as in Example 4. .

The results are shown in Figure 2.

[Example 8] The activated sludge containing actinomycetes in Example 5 was placed in a small model similar to Example 5, and the amount of dissolved oxygen in the aeration tank, the amount of added raw water, and the activity described in Example 5 were measured. Continuous operation was performed under the same conditions as the sludge return rate.

The reaction mixture set 1fc prepared in Example 4 (intrinsic viscosity [η
] was continuously added to the return sludge line in the small model for 48 hours while diluting it 100 times with tap water.

The amount of foamed scum at the aeration tank interface from the start of continuous addition of the mixed reaction composition, the SVI of the sludge in the aeration tank, and the COD of the treated water were measured in the same manner as in Example 4. .

The results are shown in Figure 2.

[Comparative Example 3] Using the same activated sludge and operating conditions as in Example 5, an antifoaming agent was added from the top of the aeration tank without adding the reaction &[l acid of the present invention. As an antifoaming agent, a special paraffin ester compound (Mikonene C from Daito Pharmaceutical Co., Ltd.) was diluted with water to 0.1% by weight and added from the top of the aeration tank at a rate of 8+el/min for 3 days.

Although the antifoaming effect was reduced in the areas where the antifoaming agent was applied, a sufficient effect was not obtained, so addition was continued for 5 days at a rate of 8II/1 part.

1 day, 3 days, and 10 days after the start of continuous addition of antifoaming agent,
After 20 days and 30 days, the amount of foamed scum at the aeration tank interface, the SVI of the sludge in the aeration tank, and the COO of the treated water were measured in the same manner as in Example 4.

The results are shown in Figure 2.

The following was found from Table 2 and microscopic observation of the activated sludge in the aeration tank.

(2) When the present invention is used, the amount of additive is small compared to Comparative Example 3, and the foaming scum caused by actinomycetes is rapidly reduced, the SVI value of the sludge is lowered, and the settling property of activated sludge is improved. The results are markedly improved and the effects last for a long time.

On the other hand, in Comparative Example 3, the foamed scum at the aeration tank interface was temporarily reduced by adding the antifoaming agent, but when the addition was stopped, the foamed scum accumulated at the aeration tank interface again.

(2) When the present invention is used, actinomycetes are extremely reduced in the sludge present in the aeration tank and settling tank compared to Comparative Example 3, and the activated sludge forms solid flocs.

■When using the present invention, the actinomycetes are destroyed and exist in the treated water and flow out, but the COO value of the treated water is 20 mg.
/1 or less, which is good as treated water.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the action of the agent of the present invention in preventing the bulking phenomenon of activated sludge caused by filamentous bacteria, and Figure 2 is a diagram for explaining the effect of the agent of the present invention in preventing the abnormal phenomenon of activated sludge caused by actinomycetes. It is a figure for explaining the effect|action of this.

Claims (3)

[Claims] (1) An agent for preventing the bulking phenomenon of activated sludge caused by at least one type of filamentous bacteria or the abnormal phenomenon of activated sludge caused by actinomycetes, the agent comprising an amine and a diepoxide, or an amine and a diepoxide and an epihalohydrin and/or an alkylene dihydrin. An activated sludge abnormality prevention agent characterized by comprising a water-soluble polymer obtained by reaction with a halide. (2) The intrinsic viscosity [η] of the water-soluble polymer is 0.02
dl/g to 0.4 dl/g (25°C), the activated sludge abnormal phenomenon prevention agent according to claim 1. (3) obtained by reacting activated sludge or activated sludge-containing wastewater containing at least one type of filamentous bacteria or actinobacteria with an amine and a diepoxide, or an amine and a diepoxide and an epihalohydrin and/or an alkylene dihalide. A method for preventing abnormal phenomena in activated sludge, which comprises adding a water-soluble polymer in an amount of 0.05 to 25 parts by weight per 100 parts by weight of dry solid content of activated sludge.