JPS625032B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a wastewater and sludge treatment tank.

BACKGROUND ART Methods such as activated sludge method and anaerobic sludge digestion method (methane fermentation method) are widely used to treat wastewater by using microorganisms to decompose organic matter in wastewater and separate the generated sludge.

The problem with these methods is how to improve the decomposition rate, decomposition rate, and treatment efficiency of organic matter, and the development of wastewater and sludge treatment tanks, such as sludge digestion tanks, aeration tanks, and methane fermentation tanks, is a problem in these methods. Improvements have been made. In particular, the above-mentioned problems can be solved by mixing and stirring the liquid remaining in the treatment tank to achieve sufficient homogenization.

As a conventionally known processing tank equipped with a stirring mechanism, there is, for example, a gas lift system that applies the principle of an air lift pump. This method involves pressurizing gas into the center or bottom of a vertical pipe installed in the center of the tank, but due to insufficient stirring power, a considerable amount of sediment and sludge accumulates at the bottom of the tank, which tends to lead to dilution of the sludge. There are drawbacks.

In addition, processing tanks equipped with agitators such as scrapers or screws have the advantage of being able to reverse the rotation direction by switching the polarity of the agitator, but it is difficult to seal the top of the tank and fibers may adhere to the screws. However, there is a drawback that the electric motor and processing capacity tend to deteriorate.

In addition, all types of conventional treatment tanks tend to produce dead spaces due to accumulated sludge, and the accumulated sludge must be removed.

An object of the present invention is to provide a wastewater and sludge treatment tank that solves the above-mentioned conventional drawbacks, and in particular, to provide a wastewater and sludge treatment tank that can perform sufficient and uniform mixing and agitation in the tank. They completed the present invention as a result of repeated studies to achieve the object of the present invention.

That is, the present invention provides a wastewater treatment system characterized in that a blowout pipe capable of blowing out wastewater and/or sludge in the same circumferential direction across the tank is provided on the inner wall of the tank, at least above the accumulated sludge in the stagnant liquid in the tank. and/or a sludge treatment tank.

The present invention will be explained in detail below based on the accompanying drawings.

FIG. 1 shows an example of an embodiment of the present invention, and FIG. 2 shows a schematic plan view of a processing tank of the present invention.

In the past, wastewater, sludge, etc. were simply pumped from the top of the tank, but in the present invention, the first,
As shown in Fig. 2, a blowout pipe 3 capable of blowing out fluid in the same circumferential direction across the tank is provided on the tank inner wall at least above the accumulated sludge 2 in the stagnant liquid in the treatment tank 1. It is used to supply water into the tank.

Thereby, it is possible to generate a swirling flow sufficient for sufficient and uniform mixing and agitation without requiring a stirrer such as a scraper or screw. Further, there is no dead space due to deposits in the tank, the throughput per volume increases, the power of the pump can be used effectively, the inside of the tank can be simplified, and it is economically advantageous.

As shown in Figure 3, the shape of the blow-off pipes may be such that wastewater and sludge can be blown out in the same circumferential direction, and the number of blow-off pipes, the blow-off flow rate, etc. will depend on the size and shape of the treatment tank. You can decide accordingly.
It is also possible to send wastewater or sludge into the same pipe in advance and then blow it out from several locations inside the treatment tank.

The outer periphery of the tank has a flow velocity (approximately 0.2 m/sec to 0.4 m/sec) that is sufficient to suspend sediment, sludge, etc., but the flow velocity decreases toward the center, so a constant flow velocity is maintained. When the amount is below, the sand and sludge settle, and are collected and deposited mainly in the center of the bottom of the tank. Due to the above effect, this accumulated sludge is kept in a small amount by the circulating sludge pump 4 in the sludge extraction route outside the tank. It is extracted periodically or intermittently, and some are recycled. Further, as shown in FIG. 1, the treatment liquid obtained from the treatment tank 1 may be separated by sedimentation in the settling tank 5, and the sludge may be returned and supplied in the same manner as the waste water or circulating sludge.

In addition, when an air lift pump or the like is used in combination with the treatment tank of the present invention as shown in FIG. 1, mixing and agitation of the upper and lower parts of the liquid staying in the tank can be promoted by gas agitation.

In addition, in the figure, 4' is a return sludge pump, and 6 is a blower.

[Brief explanation of the drawing]

FIG. 1 shows an example of an embodiment of the present invention,
FIG. 2 is a schematic plan view of the processing tank of the present invention, and FIG. 3 shows a specific example of the blow-off pipe. 1... Treatment tank, 2... Accumulated sludge, 3, 3'...
Blowout pipe, 4... Circulating sludge pump.

Claims (1)

[Claims] 1. A treatment tank for wastewater and sludge, characterized in that a blowout pipe capable of blowing out wastewater and/or sludge in the same circumferential direction across the tank is provided on the inner wall of the tank, at least above the accumulated sludge in the accumulated liquid in the tank. .