JPH0218913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an anaerobic treatment apparatus used for water treatment, and in particular to a sludge blanket type anaerobic treatment apparatus.

[Conventional technology]

The sludge blanket type anaerobic treatment equipment is
Sludge mainly composed of anaerobic bacteria forms a sludge blanket and brings it into contact with waste liquid to perform anaerobic digestion, but the gas generated during digestion rises and disturbs the sludge blanket, causing solid-liquid Since separation cannot be performed, the digestion reaction section and the solid-liquid separation section are separated. As such a digester, there is one in which a solid-liquid separation section is partitioned into an inverted triangular cross section by two partition plates having an inclination of about 45 degrees (USP No. 4253956).

[Problem that the invention seeks to solve]

However, in this equipment, the sludge in the solid-liquid separation section flows into the digestion reactor through natural settling, so if the properties of the sludge deteriorate and the settling properties become poor, the sludge will not be returned sufficiently, and the solid-liquid separation There was a problem that sludge accumulation and scum occurred in some parts, making it impossible to operate at the set load.

This invention is intended to solve the above-mentioned problems, and prevents the accumulation of sludge in the solid-liquid separation section.
The object of the present invention is to provide an anaerobic treatment device that can prevent scum generation and SS leakage into treated water, and can sufficiently return sludge to the digestion reaction section.

[Means for solving problems]

This invention provides a digestion tank having a raw solution inlet at the bottom, a first partition plate extending into the liquid at an angle from one side of the digestion tank, and an angle that intersects the first partition plate. A second partition plate extends from below the liquid level on the side and forms a sludge flow path between it and the first partition plate.
a solid-liquid separation section formed in the upper part of the digestion tank by the first and second partition plates, a digestion reaction part formed in the lower part, and the second partition plate and the wall surface of the digestion tank. a gas collection chamber that covers the upper part of the ascending flow path formed between the gas collection chamber, a liquid flow path that connects the lower part of the gas collection chamber to the solid-liquid separation section, and a gas pressure within the gas collection chamber that is adjusted. This is an anaerobic treatment apparatus characterized by having a gas pressure adjustment means.

[Effect]

In the anaerobic treatment apparatus of the present invention, when the stock solution is introduced into the digestion tank and brought into contact with the sludge blanket in the digestion reaction section to perform anaerobic treatment, the generated gas rises through the ascending channel and is captured by the gas trap. Collected in a collection room. At this time, part of the reaction liquid and sludge rises up the ascending channel together with the gas, and flows from the bottom of the gas collection chamber through the liquid channel into the solid-liquid separation section, where the solid-liquid separated liquid is processed. The sludge is taken out as a liquid and returned to the digestion reaction section from the sludge channel. When the gas pressure in the gas collection chamber is adjusted by the gas pressure adjustment means, the flow rate of liquid and sludge entering the solid-liquid separation section is adjusted, and the separation performance in the solid-liquid separation section is improved.
The accumulation of sludge is eliminated, the generation of scum is eliminated, and SS leakage into the treated water is eliminated.
In addition, the sludge will be returned sufficiently.

〔Example〕

Hereinafter, the present invention will be explained with reference to embodiments of the drawings. The drawing is a vertical sectional view of an anaerobic treatment apparatus according to an embodiment of the present invention.

In the drawings, reference numeral 1 denotes a digestion tank consisting of a rectangular parallelepiped-shaped container, and porous tubular stock solution inflow portions 2 are uniformly provided over the entire bottom surface. A first partition plate 3 is provided at the top of the digestion tank 1 on one side and extends into the liquid at an angle of about 45° from above the liquid level. In addition, a second partition plate 4 is provided that extends from below the liquid level on the opposite side at an angle of approximately 45° in a direction intersecting the partition plate 3, and the lower part of the second partition plate 4 is connected to the lower end of the partition plate 3 to prevent sludge. A flow path 5 is formed.

A solid-liquid separation section 6 is formed in the upper part of the digestion tank 1 by the partition plates 3 and 4, and a digestion reaction section 7 is formed in the lower part. A processing liquid extraction groove 9 is formed in the upper part of the partition plate 3 by an overflow wall 8 and communicates with a processing liquid pipe 10 . Further, a first gas collection chamber 11 is formed between the processing liquid extraction groove 9 and the digestion wall surface 1a, and communicates with a gas discharge pipe 12.

A rising flow path 1 is provided between the partition plate 4 and the digestion wall surface 1b.
3 is formed. At the lower end of the partition plate 4, there is a third plate inclined at an angle of about 15° in the direction intersecting the partition plate 4.
A partition plate 14 extends toward the upward flow path 13. The distances A and B between the partition plate 14 and the extinguishing wall surfaces 1a and 1b are set to be A>B (2:1 in the embodiment).

A second gas collection chamber 15 is provided so as to cover the upper part of the ascending channel 13, and a solid-liquid separation section 6 is formed from the lower part of the second gas collection chamber 15.
A fourth partition plate 17 is provided to be inclined so as to form a liquid flow path 16 communicating with the liquid flow path 16 . Liquid flow path 1
A baffle plate 18 is provided opposite to the solid-liquid separation section 6 at a position below the liquid level and does not reach the partition plate 4 .

19 is a water seal tank as a gas pressure adjusting means, which communicates with the ascending passage 13 through a communication pipe 20;
A gas discharge pipe 21 is connected to the upper part. An inner cylinder 22 with an open bottom is inserted from above the liquid level, and the insertion depth can be adjusted with a handle 23. In addition, a gas discharge pipe 24 is provided inside the inner cylinder 22.
is rising, and is connected to the gas collection chamber 15 via a connecting pipe 25.

26 is a sludge blanket formed in the digestion reaction section 7, 27 is a raw solution pipe communicating with the raw solution inflow section 2, 28 is a sludge removal pit provided at the bottom of the digestion tank 1, and 29 is a sludge removal pipe.

In the above configuration, the stock solution is supplied from the stock solution pipe 27, and is caused to flow into the digestion tank 1 from the stock solution inflow section 2,
When anaerobic digestion is performed, the raw solution is mixed with sludge forming the sludge blanket 26 in the digestion reaction section 7, and organic matter is decomposed mainly by the action of acid-producing bacteria to produce organic acids. The organic acid decomposes under the action of methane, producing methane.

A part of the gas generated as the digestion progresses in the digestion reaction section 7 is guided to the lower side of the first partition plate 3 and the third partition plate 14 and rises, and enters the first gas collection chamber 11. The gas is collected and discharged from the gas exhaust pipe 12. The remainder of the gas is guided to the lower side of the second partition plate 4 and flows into the ascending channel 1 along with the reaction liquid and sludge.
3 and is collected in the second gas collection chamber 15. The amount of gas rising in the ascending flow path 13 is the distance A,
Since it is determined by B, it can be adjusted by the length of the partition plate 14, and by setting A>B, it is desirable to reduce the amount of gas for sludge circulation to 1/2 or less of the total.

The reaction liquid and sludge rising along with the gas rising in the rising flow path 13 flow into the solid-liquid separation section 6 from the lower part of the gas collection chamber 15 through the liquid flow path 16 . Then, the reaction liquid collides with the baffle plate 18, passes above the buffle plate 18, and passes through the solid-liquid separation section 6.
into which it undergoes solid-liquid separation. The sludge passes under the baffle plate 18, flows down along the partition plate 4, and circulates from the sludge channel 5 to the digestion reaction section 7 while preventing sludge accumulation. The liquid separated in the solid-liquid separator 6 is taken out from the processing liquid extraction groove 9 to the processing liquid pipe 10. Further, the settled sludge is returned to the digestion reaction section 7 together with the sludge circulating on the partition plate 4.

The flow rate Q flowing into the solid-liquid separator 6 from the ascending channel 13 is adjusted by adjusting the gas pressure in the gas collection chamber 15 by the water seal tank 19, which is a gas pressure adjustment means. , solid-liquid separation efficiency and circulation efficiency are maintained at a high flow rate, and accumulation and scum generation in the solid-liquid separation section 6 and SS leakage to the treated water are prevented.

The gas pressure in the gas collection chamber 15 can be adjusted using the handle 2.
3 to change the insertion depth of the inner cylinder 22, and at this time, the gas in the gas collection chamber 15 passes through the communication pipe 25 and the gas discharge pipe 24,
When the liquid is discharged from the lower end of the inner cylinder 22 into the water seal tank 19 and discharged from the gas discharge pipe 21, the liquid levels l and L are
The gas pressure is adjusted according to the difference between Here, l is the liquid level of the solid-liquid separation section 6, L is the liquid level of the gas collection chamber 15 that corresponds to the tip of the inner cylinder 22, and the liquid level L is adjusted within the range of h.

In this way, by adjusting the gas pressure in the gas collection chamber 15, the liquid level L is adjusted. When the gas pressure increases, the liquid level L decreases and the flow rate Q decreases, and when the gas pressure increases, the liquid level rises and the flow rate decreases. Q increases. By maintaining the flow rate Q at an appropriate value, the separation performance in the solid-liquid separation section 6 is improved, sludge accumulation is eliminated, scum generation is eliminated, and SS leakage into the treated water is eliminated. Sludge will be returned sufficiently.

According to the experimental results, when h = 300 mm and the gas pressure in the gas collection chamber 15 is 0 mmAq, the SS in the treated water is
It was 1000-2000 mg/, but it was reduced to 100 mg/ by setting it to about 250 mmAq.

Excess sludge is concentrated in a sludge pit 28 provided at the bottom of the digestion tank 1, and is drained from a sludge pipe 29.

In the above description, the partition plate 14 may be provided separately from the partition plate 4, but by joining them as in the embodiment, short circuits of circulating sludge can be prevented and digestion can be performed efficiently. Further, although it is sufficient to simply provide a valve as the gas pressure adjustment means, the water seal tank 19 allows for easier and more accurate adjustment. The water seal tank 19 may be provided within the digestion tank 1, and in this case, the communication pipe 20 is omitted. Furthermore, the digestion tank 1 may be cylindrical with center 1a or 1b.

The present invention can be used as an anaerobic treatment device for treating organic waste liquid, sewage sludge, human waste, and other raw solutions suitable for anaerobic digestion.

〔Effect of the invention〕

According to the present invention, the gas pressure in the gas collection chamber is adjusted to maintain the flow rate into the solid-liquid separation section at a predetermined value, thereby preventing the accumulation of sludge in the solid-liquid separation section. This prevents the generation of scum and leakage of SS into the treated water, and allows sufficient return of sludge to the digestion reaction section.

[Brief explanation of drawings]

The drawing is a vertical sectional view of the embodiment, and 1 is a digestion tank, 2 is a raw liquid inlet, 3, 4, 14, and 17 are partition plates, 5 is a sludge channel, 6 is a solid-liquid separation section, and 7 is a digestion reaction. 11 and 15 are gas collection chambers, 13 is an ascending flow path, 16 is a liquid flow path, 18 is a buffer plate, 1
9 is a water seal tank.

Claims (1)

[Scope of Claims] 1. A digestion tank having a raw solution inlet at the bottom, a first partition plate extending into the liquid at an angle from one side of the digestion tank, and a digestion tank having an angle that intersects with the first partition plate. A second partition plate extends obliquely from below the liquid level on the opposite side of the tank and forms a sludge flow path between it and the first partition plate, and the first and second partition plates separate the upper part of the digestion tank. a gas collection chamber that covers the upper part of the ascending channel formed between the solid-liquid separation part formed in the solid-liquid separation part and the digestion reaction part formed in the lower part, and the second partition plate and the wall surface of the digestion tank; An anaerobic treatment apparatus comprising: a liquid flow path communicating from a lower part of the gas collection chamber to the solid-liquid separation section; and a gas pressure adjustment means for adjusting the gas pressure within the gas collection chamber. 2. The anaerobic treatment apparatus according to claim 1, wherein the gas pressure adjustment means is a water seal tank. 3 The solid-liquid separator has a second
The anaerobic treatment apparatus according to claim 1 or 2, having a full plate that does not reach the partition plate. 4 The third partition in which the second partition plate is inclined in the opposite direction to the lower end
An anaerobic treatment apparatus according to any one of claims 1 to 3, wherein the partition plates are joined.