JPH05192519A - Solid-liquid separation device - Google Patents

Abstract

(57) [Summary] [Purpose] Providing a solid-liquid separation device that can efficiently remove SS in sewage, can be applied to large-scale sewage treatment, and can easily utilize existing sewage treatment plant equipment. To do. [Structure] On the outflow side of a lateral flow tank 1 in which sewage of a solid-liquid separator flows horizontally, preferably a plurality of filter medium filling tanks 5 are provided with a partition wall 4 interposed therebetween. Each filter medium filling tank 5 has a specific gravity of 1
A filter medium made of plastic or the like below is filled, and the sewage in which the SS that is likely to settle in the lateral flow tank 1 is allowed to flow in a downward flow or an upward flow to capture fine SS. Further, the air introducing pipe 7 is arranged below the filter medium filling tank 5a to wash the filter medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-liquid separation device used for primary treatment of sewage.

[0002]

2. Description of the Related Art Conventionally, a primary settling tank has been used as a primary treatment facility for sewage in a sewage treatment plant. This first settling basin is a vertically long settling basin with a length of several tens of meters, and the sewage settles SS while slowly flowing sideways in the inside, and the settled SS is set by a scraper installed at the bottom of the pond. It is designed to be discharged to the outside.

However, such a conventional first settling tank is
Despite the large installation space, SS is separated only by gravity, so the amount of treated water per unit area is about 35 m ³ / m ² / day, and the removal rate of SS is
There is a problem that the separation efficiency is poor at about 40%. Therefore, recently, as shown in Japanese Patent Laid-Open No. 1-7920, the specific gravity is 1
A primary treatment facility has been proposed in which sewage is allowed to flow upward in a treatment tank filled with the following filter medium to remove SS in the sewage by the filter medium.

This equipment, compared to the conventional first settling tank,
Excellent SS removal capability. On the other hand, however, since it is an upward flow, it will be wound up to SS, which should naturally settle, and be trapped in the filter medium, and it is necessary to wash the filter medium frequently, so the operation stop time for cleaning relative to the operating time It has the drawback of being long and consuming much power for cleaning. Furthermore, there is a drawback that it is difficult to apply to non-small-scale sewage treatment and the first settling tank of the existing sewage treatment plant cannot be used.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and can efficiently separate SS in sewage, and can be applied to middle and large scale sewage treatment. It was completed to provide a solid-liquid separation device that can utilize the equipment of a sewage treatment plant.

[0006]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above problems, provides a filter medium filling tank with a partition wall on the outflow side of a lateral flow tank in which sewage flows horizontally, and the inside thereof. Is filled with a filter medium having a specific gravity of 1 or less, and an air introducing pipe for cleaning the filter medium is arranged below the filter medium filling portion.

[0007]

The present invention will be described in more detail below with reference to the embodiments shown in the drawings. 1 and 2, reference numeral 1 denotes a lateral flow tank of a solid-liquid separation device, and a scraper 2 similar to the conventional one is installed at the bottom of the tank. Reference numeral 3 is an inlet for sewage to the lateral flow tank 1. A plurality of filter medium filling tanks 5 are provided on the outflow side of such a lateral flow tank 1 with a partition wall 4 interposed therebetween. The sewage that has reached the outflow side of the lateral flow tank 1 overflows or troughs the upper end of the partition wall 4 and is collected, and flows into each filter medium filling tank 5. The water area of the lateral flow tank 1 and the water area of the entire filter medium filling tank 5 are preferably about 4: 1 to 2: 1.

The filter medium filling tank 5 is filled with a filter medium having a specific gravity of 1 or less. As such a filter medium, for example, a plastic filter medium can be used. For example, a hollow cylindrical filter medium having a diameter of 40 mm or less and a length of 50 mm or less can be used. It is more preferable that such a hollow cylindrical filter medium has a diameter of 20 mm or less and a length of 30 mm or less. However, the shape of the filter medium is not particularly limited as long as the SS component can be captured when the sewage flows through the gap.

In order to prevent these filter media from flowing out, it is preferable to provide a mesh 6 on the upper and lower surfaces of the filter media filling section 5a. Further, if the entire filter medium is covered with a net, the work such as replacement of the filter medium can be easily performed.

An air introducing pipe 7 for cleaning the filter medium is installed below the filter medium filling section 5a. The filter medium cleaning is performed while stopping the inflow of sewage into the filter medium filling tank 5 to be cleaned,
It is performed by a method of ejecting air from the air introduction pipe 7. As a result, the SS adhering to the filter medium is separated into water, so it is sufficient to drain it from the lower part. Since the filter medium filling tank 5 cannot be used during cleaning, it is not necessary to stop the whole operation by providing a plurality of filter medium filling tanks 5 and sequentially cleaning one tank at a time as in the embodiment.

In the first embodiment described above, the filter medium filling tank 5 is a downward flow filtration tank, but the second embodiment shown in FIG.
In this embodiment, the filter medium filling tank 5 is an upflow filtration tank. In this case, the sewage that has crossed the partition wall 4 on the outflow side of the lateral flow tank 1 is collected in the water collection conduit 4a and supplied to the filter medium filling tank 5 from the lower surface. The other structure is similar to that of the first embodiment, and the description thereof is omitted.

[0012]

Next, the operation of the solid-liquid separation device of the present invention will be described.
First, sewage is made to flow into the lateral flow tank 1 of the solid-liquid separation device from the inflow port 3, and SS is fed while flowing horizontally in the lateral flow tank 1 at a low speed.
Allow the minutes to settle. Then, the settled SS component is taken out by the scraper 2 as in the conventional case.

The sewage from which SS having a relatively large particle size has been removed by natural sedimentation then overflows at the upper end of the partition wall 4 or is collected in the trough or the water collection conduit 4a to be filled in each filter medium filling tank. Inflow to 5. As described above, since each filter medium filling tank 5 is filled with the filter medium having a specific gravity of 1 or less, the sewage flows as a downward flow or an upward flow through the floating gaps of these filter media, and in the lateral direction between them. In the flow tank 1, SS components having a small particle size that did not settle are captured by the filter medium. Thus, the sewage in which the fine SS component is captured by the filter medium in the filter medium filling tank 5 is discharged from the outlet 8 as the primary treated water,
It is sent to the next process.

In this way, the primary treatment of sewage is continued,
When the amount of SS adhering to the filter medium in the filter medium filling tank 5 increases, stop the inflow of sewage into the filter medium filling tank 5 one by one,
Air is ejected from the air introduction pipe 7 to wash the filter medium. The jetted air passes between the floating filter media in the form of bubbles, but the filter media has a specific gravity of 1 or less, so it easily flows and the SS component adhering to the surface is removed. .. During normal operation, the part of SS in sewage that tends to settle has already been removed in the lateral flow tank 1, so the amount of SS captured by the filter material in the filter material filling tank 5 is compared to the amount of treated water. And then there are few. For this reason, the cleaning interval of the filter medium in the filter medium filling tank 5 can be made sufficiently long, and it is not necessary to perform frequent cleaning.

[0015]

The solid-liquid separation device of the present invention described above has the following excellent effects. The SS component in the sewage can be removed efficiently, and the conventional first settling tank has a treated water volume of 35 m ³ / m ² / day per unit area.
While the SS content removal rate was about 40%, the apparatus of the present invention can achieve an SS content removal rate of 90% with the same amount of treated water. It can also be applied to large-scale sewage treatment. By adding a filter medium filling tank, it can be easily incorporated into an existing first settling tank. SS that easily settle is removed in the lateral flow tank, and only SS that does not easily settle is captured in the filter medium filling tank, so there is no need to frequently wash the filter medium, less power is required for washing, and washing is also possible. Downtime can be minimized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a first embodiment of the present invention.

FIG. 2 is a plan view illustrating an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a second embodiment of the present invention.

[Explanation of symbols]

 1 Lateral flow tank 4 Partition wall 5 Filter medium filling tank 7 Air introduction pipe

Claims (1)

[Claims] 1. A filter medium filling tank is provided on the outflow side of a lateral flow tank in which sewage flows horizontally, with a partition wall separating the medium, and a filter medium having a specific gravity of 1 or less is filled in the inside of the tank, and a filter medium filling section is provided below A solid-liquid separator characterized in that an air introduction pipe for cleaning the filter medium is arranged.