JPS597518B2 - Wastewater coagulation treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the use of flocculants by microorganisms, more particularly to the use of flocculants by microorganisms, and more particularly to the use of flocculants by microorganisms, and more specifically, by the use of flocculants by microorganisms, and more specifically, by the use of flocculants by microorganisms, and more specifically, by the use of flocculants by microorganisms.
This invention relates to a method for coagulating and sedimenting not only proteins but also organic substances, inorganic substances, minerals, biological cells, etc., using a flocculant-active substance obtained by culturing a flocculant-active substance-producing bacterium belonging to the genus Ematium. .

Conventionally, methods for producing protein aggregation active substances using microorganisms have been proposed, for example, in JP-A-51-86189 and JP-A-51-115993. The agglutinating active substance obtained using this method can be used not only for proteins, but also for a wide range of colloidal substances such as organic substances, inorganic substances, mineral substances, biological cells, etc. suspended, dispersed, or floating in liquids. This provides a method for achieving excellent flocculation and sedimentation.

The microorganism used in the method of the present invention has microorganism microorganism number A 4.
Dermtiaceae, which includes bacteria No. 2, 5, and 7.
Dematium of ae)
It is a flocculant-active substance producing bacterium belonging to the genus.

Hereinafter, the present invention will be described with reference number A. The case where the bacteria No. 4 2 5 7 (hereinafter referred to as Example bacteria) is used will be explained.

Example bacteria were used as a carbon source (glu case Sucrose).
), a large amount of flocculating active substance is produced outside the bacterial cells, but the present invention is capable of converting this flocculating active substance into inorganic and organic insoluble suspended solids, colloidal substances, and colloidal substances in various industrial wastewaters.
The present invention provides a flocculation method that can be used as a flocculant to flocculate and remove insoluble and soluble proteins.

The flocculating active substance used in the present invention is obtained from a culture solution containing bacterial cells, a culture solution obtained by heating and sterilizing the culture solution to physically or chemically remove the bacterial cells, or by purifying this culture solution with an organic solvent. means solid substances, etc.

Various types of wastewater to which the present invention is applied include accumulated wastewater, food industry wastewater, pulp wastewater, and other industrial wastewater.

This flocculating active rostol is added to various types of industrial wastewater in the form of liquid or solid, and the amount added varies depending on the quality of the wastewater.
The amount ranges from several ppm to several tens of ppm.

The method of addition is to stir the wastewater at 60 rpm/min, add this flocculating active substance to the liquid, add aluminum sulfate after a few minutes, and stir, and flocculation will occur in a few minutes (1 to 2 minutes).
Its floc formation is fast and its settling properties are very good.

The turbidity of the supernatant liquid was measured as T% at 720 nμ and compared with distilled water as a control.

COD is analyzed by JIS method, color value is measured at 420nμ,
The pH of the treatment solution was varied depending on the quality of the treated water, and the amount of aluminum sulfate added was also varied depending on the quality.

Among the industrial wastewater samples tested, wastewater with remarkable characteristics was tested.

Specific Examples will be described below, but for reference, the mycological characteristics of the bacteria of the Examples are explained below.

A. Mycological characteristics of the isolated bacteria Colonies initially grow on the surface as grayish-white, slimy, glossy, oil drop-shaped (fat-like) yeast-like cells, and filamentous bacterial bodies grow radially from the periphery and become curly. It is filamentous and develops like a tree.

These filamentous fungi grow well not only on the surface of the medium but also inside the medium.

After a while, light brown spots appear on the surface of the colony, which gradually turn into black spots, and finally the entire surface becomes dark black.

This filamentous fungus produces many pale brown oval or oval conidia.

These conidia easily break apart.

On the other hand, conidia are also attached to the surface of the oil droplet-shaped colony.

The culture solution containing sugars becomes very viscous and produces thick colonies of leathery black moss on the surface of the solution.

The optimum growth temperature is 20 to 25°C, at which alcohols and organic acids are produced from sugars such as glucose and sucrose, and it also has a unique aroma.

1 Cultural characteristics: yellow. (Note) ■ Solid medium: Potato, on glucose agar medium. At first, the colony has a flat surface, is transparent, has a glossy oil drop shape, and is viscous, grayish-white, yeast-like, and has a filament-like shape that curls radially from the periphery of the colony. Just dendritic fungal cells grow, and these filamentous fungal cells grow well not only on the surface of the medium but also inside the medium.

Eventually, some parts of the tree-like branches turn blackish brown.

After 3 to 4 days of culturing, light brown spots appear on the surface of the colony, which gradually becomes dark black and spreads over the entire surface, and finally becomes black as a whole (after 7 days of culture).

Although growth is slow on Zuavec agar medium, the culture characteristics are as described above. It takes about 3 weeks for the colony surface to become completely black.

@Liquid culture: Potato and glucose medium Midpoint Bacterial cells grow in a floating state (3 days of culture), colonies gradually increase, and eventually (7 days of culture) the liquid is filled with viscous 7 Rony.

Then, dark black fungal moss appeared on the tube wall and gradually formed on the liquid surface (15 days of culture).

This fungal lid is thick and gelatinous.

Although it grows in the same way in Zuavec medium, it is very slow and the number of bacterial cells is small, and after about 3 weeks of culturing, a considerable black fungus moss is formed on the liquid surface.

2. Morphological characteristics The young cells are transparent, filamentous, curly, and arborescent, and the fungal cells (filamentous) have black, oval, spore-like bodies growing laterally here and there.

In addition, the oil drop-shaped colonies have black spore-like substances attached to them.

This will fall apart if you give it a shock.

3 Physiological Characteristics Optimal growth temperature is 20-25°C. Viscous substances are produced from glucose, sucrose, etc. Alcohols and organic acids are produced from sugars such as glucose. It has a unique aroma.

Yellow ■References include An introduction to ind. by George Smith.
(ustrialmycology) (p6 8-9
7) Based on Applied Microbiology (pages 83-87).

B Isolation of bacteria and detection of flocculation Make a 5-part solution of raw sugar as a bacterial isolation medium, sterilize it in the usual way, pour it into a 100 fnl Erlenmeyer flask, adjust the pH to slightly acidic, and then pour it again. After sterilization, 1 rrl of the stock solution described below was added to this liquid medium, cultured by a static method (Murobuchi 25-30°C), and samples were taken every day to examine aggregation.

That is, a 1% solution of kaolin (special grade reagent manufactured by Takeda Pharmaceutical Co., Ltd.), which is normally used in agglutination tests, was prepared, and the pH was adjusted to slightly acidic to prepare a test solution.

The above stock solution is a dilute solution of granulated sugar, a dilute solution of raw sugar that had been left in a beaker for a long time during analysis (a solution dialyzed with a 24A (diameter) cellulose membrane). I noticed that the viscosity had increased, so I went through E to undergo dialysis again.

During the operation, when a small amount of diatomaceous earth or activated carbon is added, this solution exhibits a very significant flocculating property, i.e., the diatomaceous earth or activated carbon instantly solidifies at the bottom of the beaker, unlike other commercially available flocculants. I discovered that there is no cohesive force.

Furthermore, various substances, such as kaolin, bentonite, etc., containing aluminum silicate as a main component, or inorganic substances, i.e., neutral salts such as calcium carbonate, barium myelate, silver chloride, etc., are added to this solution.
It was qualitatively confirmed that no significant aggregation occurred when organic substances were added.

For this agglutination test, add 25rr of this sample solution to 50 test tubes.
ll*D, 11 times of the culture solution was added to this, stirred up and down 10 times, and then allowed to stand still for 3 minutes.The turbidity of the supernatant was measured using a photoelectric colorimeter.

In addition, the amount of kaolin remaining in the supernatant liquid was measured by gravimetric method and the flocculation property was investigated. As a result, the flocculation property was remarkable from the culture solution at the initial testing time.

This suggests that the flocculant active substance metabolized into the medium has an aggregating effect even in small amounts.

As the culture time progresses (96 hours), acetone, butanol. I started wandering around the smelly room.

Therefore, the culture time was set to 72 hours, and the culture was repeated 10 times to produce a culture solution with strong cohesive force, no acetone or putanol odor, and a culture solution with a unique aroma (rose flower aroma). Is this fungus pure from this liquid? went.

Pure isolation of this bacterium ~ raw sugar or sucrose (swallow sugar) 5
Make a p. Adjust to H5-6, add 0.2% powdered yeast extract (manufactured by Takeda Pharmaceutical), and add agar (0.1%).
6%) was added, heat sterilized by a conventional method, and dispensed into petri dishes to prepare a separation medium.

The culture solution was diluted 100 times, 200 times, and 500 times with sterilized water, and lrnl aliquots were poured into petri dishes and cultured at 30°C.

As a result, three types of colonies were detected, and slant culture and liquid culture were repeated to isolate pure three types of bacteria.

All colonies at the initial stage of culture (around 48 hours of culture) are cream-colored, but as time passes, the center of the surface of the colony becomes black, and as time passes, black hyphae appear on the back of the colony, centered around the colony. The bacteria that grows into the medium in a root-like manner are called isolated bacteria ■.

A bacterium whose cream-colored colony fades without changing color with the passage of time is called an isolated bacterium (■), and a bacterium whose cream color turns brown with the passage of incubation time is called an isolated bacterium (■).

The three types of isolated bacteria were statically cultured in a culture solution with the above composition,
The cohesive force of the culture solution was examined using a kaolin 1 solution.

The results showed that only isolated bacteria ■, that is, bacteria whose colony surface turns black over time and black hyphae extend like roots on the back side, have flocculating properties, and the viscosity on the brood of the main culture solution changes over time. In addition, an aroma unique to this fungus (rose flower aroma) was detected.

No aggregation was detected in the culture solutions of the other isolated bacteria ■ and ■, but an acetone odor was detected for the isolated bacteria ■, and a butyric acid odor was detected for the isolated bacteria ■.

This isolated bacterium (1) is a flocculating active substance-producing bacterium belonging to the genus Dematium of the family Dematiaceae.

C Cultivation and production of flocculants using isolated bacteria ■ Purely isolated bacteria I (Demati aceae De
The results of the production of aggregated substances using the genus Ma-tium and the culture conditions are as follows.

Using hexoses such as glucose, fructose, and galactose, or disaccharides such as sucrose, and polysaccharides such as lees as a carbon source, add 0.2% yeast extract to this, culture by standing method, and culture after 1 week. The flocculating properties of the liquid were adjusted, but in any case, a culture medium with flocculating properties was obtained.By simply adding glucose, etc. as a carbon source to a commonly used synthetic medium, such as CZapeke medium, flocculating substances could be added to the culture medium. Produce.

As mentioned above, it was found that a simple medium composition containing carbohydrates as the main component produced aggregated substances in the culture solution.

For example, if raw sugar is used as a carbon source, it is not necessary to add other nutrients (N source minerals, etc.).

It was found that as the concentration of the carbon source in the medium was cultured at a concentration of 5 to 20%, the production amount of flocculating substances with respect to the substrate decreased as the concentration increased, and that a ratio of around 5 was good.

In other words, since the viscosity of this flocculating substance is extremely high, it was determined that the growth of bacteria would be physically inhibited when this substance reached a certain concentration.

The pH does not require particularly strict adjustment if it is initially adjusted to be slightly acidic.

It becomes slightly acidic during the course of culture.

Both static and shaking culture produce aggregated substances, but it was found that shaking culture produces aggregated substances faster.

The yield of this flocculating substance based on the substrate (carbon source) is 10% or more and is inversely proportional to the substrate concentration.

Culture conditions, medium, elementary carbon source, glucose, concentration 5, fructose, 5%, granulated sugar, concentration 5, raw sugar, 5% N source, powdered yeast added to the medium other than raw sugar at 0.2 volume, pH adjusted to 5.0 with HCt, temperature 28 ~30℃ The inoculum is a culture solution obtained by culturing this isolate ■ with shaking for 7 days.
r1l was added.

D Separation and purification method of flocculated substances produced by this isolated bacterium
tium genus) was inoculated and cultured, the culture solution was heated (10
0°C/5 minutes), centrifugation 3,000 rpn/mi
When the bacterial cells are removed by filtration or filtration, and ethanol is added to the separated solution to a concentration of 30 to 40% (acetone or methanol may be used), the liquid level of the ethanol and culture solution increases. When a thin film is poured into the liquid and stirred, the fibrous or cotton-like substance instantly aggregates in one place.

The aggregated substance is separated by single-center separation or attached to a stirring rod, dissolved in water again, ethanol is added to cause re-agglomeration, and the aggregated substance is obtained by drying under reduced pressure.

The separated aggregated substance is grayish white and can be easily powdered.

It is inferred that this substance is a homogeneous high-molecular-weight substance because it coagulates instantaneously with low concentration of ethyl alcohol.

Separation and Purification Method■ It was found that the flocculating substances in the culture solution flocculate significantly when aluminum ions are added in acidic conditions, and that they flocculate due to calcium ions in alkaline conditions.

The aluminum ion to be added is aluminum chloride or its polymer, and the calcium ion is added as a chloride.
Also, lime etc.

A method for separating aggregated substances in a culture solution was established.

That is, after heat-treating the culture solution (100°C/5 minutes), bacterial cells are removed by E-filtering or centrifugation, and 0.05-0.
．． Is the 10% inorganic ion, that is, an aluminum compound when the liquid is acidic, and a calcium compound when the liquid is alkaline?
When added and stirred, the flocculated substance will be completely flocculated.

This can be separated by E filtration or centrifugation, and dried to obtain a solid powdery agglomerated substance.

Separation and purification method ①; After heat-treating the culture solution (100° C./5 minutes), remove the microbial cells, and concentrate the solution containing no microbial cells (approximately 10%) to use as a flocculant.

When used industrially as a flocculant, it is very rational to use it as a liquid during production, as this substance is a very stable substance and does not require dissolution during use. be.

The table below summarizes the separation and purification methods for this substance (agglomerated substance).

Separation of this substance by addition of inorganic salt, Separation method (2) involves quantifying the concentration of this substance in the culture solution and adding the calculated amount of inorganic salt, since this substance and inorganic salt react quantitatively.

Since the residual liquid from separation method (2) contains some residual carbon source, it is adjusted to a pH suitable for culture and used repeatedly.

The added inorganic ions, such as aluminum, do not act as culture inhibitors for the bacteria.Use or use as a flocculant.Isolated bacteria (1), ie, Dematium genus of the family Black Mycoceae, was cultured and obtained by the above separation method.

Liquids, solids, and solid aggregates containing inorganic ions can be dispersed, suspended, colloidal, or suspended in water or water-containing liquids by adding very small amounts of 0.1 to 2.0 ppm based on the amount of liquid. It was discovered that it has the property of completely coagulating and precipitating organic and inorganic substances and biological bacteria.

It should be noted that the flocculating effect of this substance is significantly stronger than that of existing commercially available flocculants (inorganic and organic).

Furthermore, since it is a metabolite of microorganisms, it has the advantage of not having the problem of secondary contamination caused by flocculants.

The optimum pH range for aggregation is acidic to slightly acidic; alkaline conditions do not provide sufficient cohesion.

■The reaction lagoon is unrelated to the cohesive force from room temperature to high temperature.

(2) It is advantageous to perform gentle stirring after adding the flocculating substance.

■The amount used as a flocculant is 0.1p″pm to 3.Opp
m may be sufficient, and the amount used is not related to substances to be aggregated except for special substances.

On the acidic side, for substances that do not agglomerate with this agglomerating active substance, such as cellulose powder, starch particles, etc., this aggregating active substance is added and stirred, and then 1/30 to 1/30 of the added aggregating active substance is added.
It was discovered that when 1/40 of aluminum ions were added and stirred, cellulose powder, starch particles, etc. coagulated and precipitated instantly.

This means that on the acidic side, all organic substances that are suspended, dispersed, floating, or colloidal in water can be coagulated and precipitated.

Although the cohesive force of this cohesive substance on the alkaline side is very weak, it was discovered that by adding calcium ipane, the cohesive force becomes similar to the cohesive force of this substance on the m side. did.

The amount of calcium ions added is greater than the amount of aluminum ions added on the acidic side, and is
-30 times the amount, i.e. 40-80 ppm is required.

The results of this experiment showed that in all pH ranges, this flocculating active substance can be suspended, dispersed, floated, and colloidally present in water in a very small amount, making it possible to flocculate and precipitate organic and inorganic substances. .

The aggregation effect of this substance is due to its extremely uniform high molecular weight and extremely high affinity for water (this inference can be made from the fact that it coagulates instantly with low concentration of alcohol), as if it were a fine-grained net in water. When charged particles or inorganic substances enter this uniformly packed state, the dispersed net loses its electrical balance and clumps together, just like catching fish with a net. Material capture and inference.

Does this mean that aluminum ions are flocculated when a small amount is added to the aqueous solution of this flocculating active substance? It becomes clear through observation.

・Also, when ethanol is added to a solution of this flocculating active substance, a thin film is formed on the interface, similar to when a collodion film is formed, and it can be observed that many such films overlap.

The flocculating substance is used in the form of an aqueous solution.

In addition, the aluminum-containing flocculating substance and calcium-containing flocculating active substance obtained by purification method (1) are used as an alkaline or acidic aqueous solution.

F Physical and chemical properties of this active substance This flocculated active substance separated and purified with ethanol is soluble in water, and the specific viscosity of a 0.1% aqueous solution is 4 to 5, which is 4
Corresponds to the viscosity of a zero coefficient solution.

The Anthrone, Mauritsch, and Puret reactions of this flocculating active substance are all ■, and the qualitative reaction of one COOH group by carbazole reaction is also ■, and when the quantitative value is expressed as galacturonic acid, the content is 10 to 15. be.

Also, when hydrolyzed with INH2SO4 for 24 hours, undecomposed substances remained, and the sugar composition of the hydrolyzed solution was determined by paper chromatography.
Sugars such as glucose, galactose, and mannose were detected.

In this infrared chromatography, absorption of 1-COOH was confirmed, but the absorption of amide groups and the like was not clear.

This aggregation active substance is estimated to be a high molecular weight substance containing an organic acid whose main constituents are glucose, galactose, etc.

Viscosity sample concentration of aggregating active substance purified and separated from culture solution
Relative viscosity (c p) centipoise gAOOml! Yell
(30°C, pH6.5) 0.01 1.
620 0.0 5 2.2 0 0 }0.10 5.200 No change in viscosity in acidic and alkaline solvents i. o o o Sample concentration Relative viscosity (CP) centipoise g/100
7727! yel 30℃ 55℃ 0.01 1,620 1. 6 to O
．． 05 2.200 2, 1 000.
10 5,200 5. 1 00 Elemental analysis of purified and separated agglomerated active substances H 6.52 Section C 41.04 NO. 14 0 51.74 Ash O. 56 (hygroscopicity ■) Molecular weight 100 or more (estimated) Qualitative reaction Anthrone reaction ■ Carbazole reaction ■ Puret reaction ■ Ninhydrin reaction Ethyl alcohol Insoluble Ethanol Acetone Carbon tetrachloride Butanol Ether Solubility in ethyl alcohol (alcohol) 40% or less Soluble 40-45% Insoluble, becomes albumen-like.

Water retention: 45 or higher It becomes albumen-like or film-like (collodion film), but when agitated, it becomes a flocculent aggregate.

Odor of purified and separated flocculating active substance Odorless taste Non-hygroscopicity Weak (room temperature) Color Grayish brown fibrous substance Dilute solution of the substance (agglomerating active substance) (concentration 1-100p)
pm) and Ca++. A7 ---I Mgs Z n
When divalent or trivalent inorganic ions such as 9Pd or heavy metal ions are added (in an equal amount or 1710 or less), this substance completely aggregates and becomes fibrous.

This reaction with inorganic ions is quantitative.

Example 1 Treatment test results of sugar refining industrial wastewater (wastewater containing fine activated carbon) Analysis value of untreated fine activated carbon containing water pH 10.5 Transmittance T factor (83) S
S. 40 ppm to 50 ppm Apparent color (black) Average particle size 320 mesh or less Fine carbon in sugar refinery wastewater (granular carbon regeneration washing water) usually remains undisturbed for a long time (24 hr to 48 hr) Almost no carbon settles and the drained liquid is black in color.

1 to 3 ppm of this microbial flocculant was added to this waste liquid, and the pH
It was found that when the temperature was adjusted to around 7 and klppm of anobenium sulfate was added, carbon instantly formed flocs, the flocs settled, and the drained liquid became a transparent liquid similar to distilled water.

Table 1 shows the test results.

This microbial flocculant can completely flocculate insoluble suspended matter such as fine particles of activated carbon by using it together with aluminum sulfate at around pH 7.

Especially when the concentration of suspended solids in yellow is very dilute (for example, several pI)
m) can also be aggregated.

Example 2 Treatment test results of pulp waste liquid, K company, Kp waste liquid Pulp waste liquid (Kp waste liquid) was diluted to 1/1O, and the pH was adjusted to 6.
．． It was adjusted to 0 and used as an experimental sample.

When the pulp Kp waste liquid is diluted to 1710, the microbial flocculant is added thereto, and aluminum sulfate is added after stirring, a large amount of soluble substances become flocs and the supernatant liquid becomes transparent.

Floc formation and sedimentation of the formed flocs are completed in a few minutes.

When this flocculant is used for pulp drainage, the pH is adjusted to neutral and the coagulant is diluted to about 1/10.

The effects of pulp drainage using this flocculant are remarkable in decolorization and insolubilization of soluble substances.

The E-transactivity of the formed flocs is very good and the result is second to none.
Shown in the table.

Example 3 Treatment test results of noodle production wastewater Noodle production wastewater pH 6.0 C. 0. D5667ppm S. 8 4100ppm As a result of using flocculant 6-9ppm and aluminum sulfate 2ppm, when this microbial flocculant was added to noodle production wastewater, the pH
C.6-7. O. 80% of D can be removed and the transmittance is 8.
It becomes 9-88%.

It was found that the flocculation took only a few minutes and the E-transitivity of the flocculated material was very good.

Normally, it is very difficult to treat wastewater from noodle production, and no treatment method has been established.

By adding several ppm of this microbial flocculant, the water quality of noodle production wastewater can be significantly improved.

C. of noodle-making wastewater. O. D.S. 2 if the concentration of S is high;
When the flocculant was diluted to about 0 0 0 ppm and treated, the results were shown in Table 3.

Example 4 Treatment test results for bean paste manufacturing wastewater.Bean paste manufacturing wastewater pH6.2C. 0. D 5750pp
m red S. S L680ppm In the case of bean paste manufacturing wastewater, after adjusting the pH of the wastewater to 10 to 12 with tcaO, adding 2ppm of this microbial flocculant will cause C.I. 0
．． D can remove 70 units.

Table 4 shows the results of these payments.

The sedimentation properties of the flocs formed are very good.

When used in combination with aluminum sulfate at pH 6-8 of wastewater, C.I. 0. D removal rate is poor.

Example 5 Treatment test results for pig urine wastewater When this microbial flocculant was added to pig urine wastewater, aluminum sulfate was removed. When added, white flocculent flocs are instantly formed, and the flocs have very good sedimentation properties, and the supernatant liquid becomes transparent.
Its transmittance will be 99.0%.

In addition, the decolorization rate is 95.0% and C. 0. 40% of D can be removed, and the E filtration of the settled flocs is very good.

The amount of settled floc is 0.1 to 0 per 100 - of pig urine wastewater.
．． It is 04%.

Normally, pig urine wastewater treatment is carried out in various ways, such as activated sludge treatment, but the color value of the treated liquid, C. O. D. There are many problems with turbidity, etc., which have not been solved yet.

When treated with the addition of a flocculating active substance by this microorganism, the transmittance and decolorization rate are greatly improved, and C. 0. Since D is also removed, the problem of treating pig urine wastewater is solved and at the same time the treatment can be streamlined.

The results are shown in Tables 5 and 6.

Example 6 Results of flocculation treatment test of microbial sludge obtained by treating pig urine wastewater with photosynthetic bacteria. Livestock wastewater treatment such as pig urine is treated with photosynthetic bacteria as described in Japanese Patent Publication No. 11979/1979. but,
It is extremely difficult to separate bacterial cell sludge from the treated solution by sedimentation, and a solution to this problem is desired.

When this microorganism agglutinating active substance is used in combination with aluminum sulfate, the separation is very quick and complete, and at the same time, the color value or transmittance of the supernatant liquid is improved.

The results were conducted on the photosynthetic bacteria treatment solution, and it was found that the effect was excellent.

Supernatant T% (transmittance) 99-99.5%, decolorization rate 50
% or higher, the appearance becomes similar to colorless and transparent water.

From the above results, it has been found that the present flocculating active substance has a remarkable effect on liquids or wastewater containing microorganisms, especially bacteria, and it can be seen that it can be advantageously used in wastewater treatment by sedimentation separation.

Claims (1)

[Scope of Claims] 1. A flocculant containing as an active ingredient a flocculating active substance obtained by culturing a flocculating active substance producing bacterium belonging to the genus Dematium of the family Dematiaceae? A method for coagulating wastewater treatment characterized by adding it to various wastewaters and performing coagulation sedimentation treatment. 2. The method for flocculating wastewater according to claim 1, wherein a flocculant containing a flocculating active substance as an active ingredient is used in combination with an aluminum compound. 3. A method for coagulating wastewater according to claim 1 or 2, in which a flocculant containing a flocculating active substance as an active ingredient is used in combination with calcium ions in an alkaline state for various wastewaters.