JP2655032B2 - Activated sludge bulking remover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agent for eliminating bulking of activated sludge in a wastewater treatment apparatus.

[0002]

2. Description of the Related Art The activated sludge method is widely used as a method for treating wastewater containing organic substances such as general household wastewater and industrial wastewater. The activated sludge process involves contacting the wastewater to be treated with activated sludge, which is an aggregate of microorganisms, to absorb and decompose and remove organic matter, and to separate the activated sludge from the treated water using the specific gravity difference between the treated water and the treated water. It consists of a separation step for sedimentation. However, the activated sludge swells in the treatment process, and the specific gravity of the sludge with respect to the treated water is reduced, so that the phenomenon that the treated water and the activated sludge are not smoothly separated in the separation step frequently occurs.

Such a phenomenon is called bulking. In particular, when bulking is caused by the propagation of filamentous bacteria, the sedimentation of the activated sludge is extremely reduced. In addition to overflowing, not only water pollution at the discharge destination occurs, but also continuous use of the wastewater treatment device may not be possible.

As a method for eliminating such bulking, a method of adding urea or amino acids to prevent the abnormal growth of filamentous bacteria in the activated sludge of wastewater treatment (Japanese Patent Application Laid-Open No. 52-8665), Alternatively, a method of preparing nitrogen and phosphorus by adding urea and sodium phosphate has been proposed. However, these methods have drawbacks such as requiring a long period of time for treatment, a high chemical cost, and the effect is not clear.

Further, in order to settle suspended matters in sludge, a method of adding bentonite, cristobalite or the like (Japanese Patent Laid-Open No. 175599/1985), or a method of adding ferric chloride, polyaluminum chloride and cationic polymers, etc. A method of adding a flocculant is known. Although these methods have a rapid sedimentation improving effect, they do not have a bactericidal action against filamentous bacteria, so they do not lead to a fundamental solution, and need to be continuously added. There was the disadvantage that it had to be used.

Further, as a method of eliminating bulking by sterilizing filamentous bacteria, a method of adding a mixture of chlorhexidine hydrochloride, gluconic acid and chlorhexidine (Japanese Patent Publication No. 1-37364), dialkylamine, ammonia and epihalohydrin For adding a water-soluble cationic polymer obtained by the reaction of polyalkylenepolyamine with epihalohydrin (Japanese Patent Application Laid-Open Nos. 63-218299 and 2-169,096)
However, in order to maintain an effective concentration at which all of these agents exert a bactericidal effect of filamentous bacteria, it is necessary to continuously add a large amount of agents, and other useful activated sludge bacteria are required. In addition to showing a bactericidal effect, there were difficulties in environmental impact and economics.

As a method for eliminating bulking other than the above, a method of adding chlorine gas, sodium hypochlorite, hydrogen peroxide or ozone is known, but chlorine gas is highly toxic and difficult to handle. In addition, these chemicals also have an adverse effect on microorganisms in activated sludge, so it is difficult to calculate the amount to be used at the time of use, and special knowledge is required. is the current situation.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a smartphone.
Activity due to C. erotilus natans and type 021N
Eliminates bulking sexual sludge, and without affecting the microorganisms and treated water in activated sludge, these filamentous fine
An object of the present invention is to provide an agent capable of eliminating bulking caused by bacteria .

[0009]

The present inventors have Means for Solving the Problems] As a result of performing various tests activated sludge bulking view of such circumstances has occurred widely collected by, Sphaerotilus Na
Activated sludge bulk due to lance and type 021N
It has been found that alkylpyridinium halides are effective in eliminating aging, and that they do not affect the microorganisms in the activated sludge and the treated water, thereby completing the present invention.

The alkylpyridinium halide used in the present invention is represented by the general formula shown in Chemical formula 1, and typical examples thereof include ethylpyridinium bromide, n-butylpyridinium chloride, dodecylpyridinium chloride, Hexadecyl pyridinium chloride, hexadecyl pyridinium bromide and the like can be mentioned. These alkylpyridinium halides react alkyl chloride and pyridine under heating and stirring,
After completion of the reaction, the product is obtained by steam distillation of the product to remove unreacted pyridine and recrystallization.

[0011]

Embedded image

In using the bulking-removing agent of the present invention, the powdered bulking-removing agent is directly added to the activated sludge to the aeration tank and the return sludge line of the activated sludge treatment apparatus in which the filamentous bulking is generated. A method in which a solution prepared by dissolving a bulking-dissolving agent in water is dropped or added, or a method in which an inorganic porous carrier is impregnated and added is used.

When the bulking-removing agent of the present invention is used, the amount of the bulking-removing agent to be added varies depending on the breeding state of filamentous bacteria, but is usually 0.1 to 100 parts by weight of the dry solid content of the activated sludge. What is necessary is just to add so that it may become the ratio of 05-5 weight part. When the bulking remover added at this time is less than 0.05 parts by weight, the sterilizing effect on the filamentous bacteria is low, so that the removal of the filamentous bulking is difficult. Is adversely affected and normal processing is not performed.

[0014]

[Function] Filamentous bacteria that cause the occurrence of bulking are cells that are covered by the sheath, which is the core of the nucleus, and are less susceptible to external influences than ordinary microorganisms.
In addition, the cells in the sheath are actively activated even when the sheath is destroyed and released outside, and re-form the filamentous body.To eliminate bulking, the cells in the sheath, which are the core of filamentous bacteria, are killed. Need to be done.

The bactericidal effect on the filamentous bacteria propagated in the activated sludge appears 2 to 5 hours after the addition of the alkylpyridinium halide of the present invention, and the cells of the filamentous bacteria regularly contained in the sheath are destroyed. The state can be observed, and after a further time, the sheath can be observed to be cut at various places and released as fine fragments. As the filamentous bacteria are killed, bulking is eliminated, and a sludge index value (hereinafter, SVI: Sluge) indicating the sedimentation of activated sludge
Volume Index) drops rapidly, and the activated sludge returns to a normal state with good sedimentation.

The alkylpyridinium halide of the present invention has no effect on activated sludge and can selectively kill filamentous bacteria. Alkylpyridinium halides are known to be excellent bactericides as quaternary salts, but the phenomena and reasons that can selectively kill filamentous bacteria in activated sludge have not yet been elucidated. Not in.

[0017]

【Example】

(Example 1) 10 liters of activated sludge from a complex-combined treatment tank having a dry solid content (hereinafter, referred to as MLSS) of activated sludge of 1420 ppm and an SVI of 180 was put into an aeration tank having a capacity of 12.5 liters. While performing aeration at 7 L / min, artificial sewage adjusted to contain 0.36 g / L of glucose and 0.12 g / L of polypeptone was continuously added to the aeration tank at a rate of 10 L / day using a metering pump. Then, when activated sludge was cultured, sphaerotilus natans grew, and after 6 days, M
The bulking activated sludge had an LSS value of 1500 ppm and an SVI value of 650.

In this state, 40 mg of hexadecylpyridinium chloride monohydrate was uniformly added to the aeration tank, and after 24 hours, the activated sludge had an MLSS value of 14%.
The SVI value was 00 ppm and 220. When observing the state of the filamentous bacteria at this time, it was found that the cells of spherothylus natans contracted in the sheath and some cells fell off the sheath.

After 3 days, the activated sludge has an MLSS value of 1660.
The ppm and SVI values were reduced to 140, indicating that the activated sludge had good sedimentation. Observation of the state of the filamentous bacteria at this time revealed that the sheath of the filamentous bacteria was cut at various locations and became fragments, which were released from the flocs of the activated sludge. Most of the cells in the sheath had fallen off the sheath.

After 6 days, the activated sludge has an SVI value of 120 to 1
It was stable at 40 and good sedimentation was maintained. When the state of the filamentous bacteria was observed, no new filamentous bacteria grew. The BOD value of the treated water during the test period was maintained at 20 ppm or less, and there was no adverse effect on the treatment function due to the addition of the bulking remover of the present invention.

(Example 2) Filamentous bacteria were cultured in the same continuous treatment system as used in Example 1, and spherothylus natans and type 021N bulking sludge (MLS) were used.
S value: 1420 ppm, SVI: 520) were obtained. Next, 30 mg of dodecylpyridinium chloride was uniformly added to the aeration tank, and the culture of the activated sludge was continued. After 18 hours, the activated sludge had an MLSS value of 1300 ppm and an SVI value of 320. Observation of the state of the filamentous bacteria at this time confirmed the same state as in Example 1.

The activated sludge after 3 days has an MLSS value of 1460.
ppm, SVI value is 180, and MLSS after 6 days
The value was 1670 ppm and the SVI value was 140. Filamentous bulking was eliminated and a good sedimentation state was maintained. No new filamentous bacteria grew. The quality of the treated water during this test period was 2 BOD.
0 ppm or less was maintained, and there was no adverse effect on the processing function.

(Example 3) Filamentous bacteria were cultured in the same continuous treatment system as used in Example 1, and spherothylus natans and type 021N bulking sludge (MLS) were used.
S value: 1030 ppm, SVI: 920). Next, 150 mg of n-butylpyridinium chloride was uniformly added to the aeration tank, and the culture of the activated sludge was continued. Fifteen
Activated sludge after time has an MLSS value of 1100 ppm, SV
The I value was 460. Observation of the state of the filamentous bacteria at this time confirmed the same state as in Example 1.

After 3 days, the MLSS value is 1240 ppm,
The SVI value is 240, and the MLSS value is 14 after 6 days.
The SVI value was 10 ppm and the SVI value was 160. Filamentous bulking was eliminated and a good sedimentation state was maintained. No new filamentous bacteria grew. The quality of the treated water during this test period was 20p BOD.
pm or less, and there was no adverse effect on the processing function.

(Embodiment 4) MLSS value is 1700 pp
m, 10 liters of activated sludge from the combined treatment tank having an SVI value of 230 were placed in the same treatment apparatus as used in Example 1, and aerated with 0.55 g / glucose.
Liters and artificial sewage adjusted to contain 0.12 g / l of Ehrlich meat extract were continuously added to the aeration tank at a rate of 10 liters per day using a metering pump,
When activated sludge was cultured, types I-5 and II-4
(Filamentous bacteria are classified according to Kono et al.) As bulking sludge having an MLSS value of 1620 ppm and an SVI value of 52.
It became 0.

Here, 50 mg of hexadecylpyridinium chloride monohydrate was uniformly added to the aeration tank. The activated sludge 15 hours after the addition has an MLSS value of 1780 pp.
m and SVI value were 340. When observing the state of the filamentous bacteria at this time, it was observed that the type I-5 and II-4 cells were contracting in the sheath, and a bactericidal action against the filamentous bacteria was confirmed.

The activated sludge after 3 days has an MLSS value of 2020.
ppm, SVI value is 170, and MLSS after 6 days
The value was 2300 ppm and the SVI value was 140. Filamentous bulking was eliminated and a good sedimentation state was maintained. No new filamentous bacteria grew. The quality of the treated water during this test period was 2 BOD.
0 ppm or less was maintained, and there was no adverse effect on the processing function.

(Comparative Example) In Examples 1 and 4, the same treatment was carried out except that the bulking-removing agent of the present invention was not added, and no improvement in bulking was observed. The SVI value was 500 or more, and the state of poor sedimentation was maintained.

When the bulking-removing agent of the present invention is used, the addition of a small amount of the agent enables the addition of spherothylus natans and taurine.
It is possible to eliminate the bulking of the activated sludge due to the IP 021N and to eliminate the bulking without affecting the microorganisms in the activated sludge and the treated water.

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Claims (1)

(57) [Claims] 1. Spherothylus natans and type 021N containing an alkylpyridinium halide as an active ingredient
Bulking eliminating agent of activated sludge due to.