JP2001310193A - Sewage treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for simply lowering the water level of a carrier filter tank at the time of washing of a filter carrier and a carrier separator hard to block up, capable of obtaining stable separation action and good in workability at the time of maintenance, in a sewage treatment apparatus using a carrier on which microorganisms are fixed. SOLUTION: At the time of washing of a filter carrier, the water level in an upstream tank positioned on the upstream side of the carrier filter tank is lowered by the forcible transfer of the filter carrier and the treated water in the carrier filter tank is transferred to the upstream tank to lower the water level in the carrier filter tank and, thereafter, the filter carrier in the carrier filter tank is washed. The surface of the filter screen of the carrier separator is arranged at the central part in the vicinity of the water surface of the tank in parallel to the water flow at the water surface part of the revolving flow in the carrier filter tank at an angle of 30<-<90 deg. with respect to the horizontal surface. Since the surface of the screen is arranged at the central part in the vicinity of the water surface, visual confirmation is easily performed and cleaning work by a brush, or the like, is easy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment apparatus and, more particularly, to the above-mentioned apparatus characterized by separating a carrier from transferred sewage and washing a carrier in a carrier filtration tank filled with a filtration carrier.

[0002]

2. Description of the Related Art When removing solids with a filter carrier filled in a carrier filter tank, the filter carrier may be clogged by long-term operation. Normally, to prevent this, it is necessary to periodically wash the filtration carrier and remove the filtered solids, but if the carrier is washed by aeration or mechanical stirring, the water level in the tank rises and the separated solids May be transferred to the next tank. In general, in order to prevent advection to the next tank, the water level in the carrier filtration tank is lowered in advance, and then washing is performed.

Hitherto, as a means for lowering the water level of a carrier filtration tank, a structure has been put to practical use in which a buffer chamber is provided in the tank and a capacity corresponding to the water level drop is temporarily stored.

FIG. 6 shows an example of a structure in which an air tank 25 is provided below the water surface as a buffer chamber, and the water level is lowered by replacing the air in the tank with sewage in the tank before washing. When the air tank is below the surface of the water and there is no need to lower the water level, buoyancy is constantly generated, and strength is required for the fixed portion of the air tank.

In a sewage treatment apparatus provided with a flow rate adjusting section, the flow rate adjusting section can be used as a buffer chamber. During the time when the flow control unit is not full, the treated water in the carrier filtration tank is moved to the flow control unit to lower the water level in the carrier filtration tank to wash the filtration support. It is not necessary to provide an extra structure in the tank, but it is difficult to adopt this unless the sewage treatment apparatus has a flow rate adjusting unit.

Further, the carrier to be filled in the carrier reaction tank is floating and flowing, and a carrier separation device equipped with a filtration screen is indispensable for transferring only the treated water to the next tank, for example, the carrier filtration tank. It is. Conventionally, a filtration screen of a carrier separation device has a filter screen that is perpendicular to the horizontal plane or has substantially the same angle as the horizontal plane, and is arranged in parallel to the oblique flow on the way from the upward flow to the horizontal flow or from the horizontal flow to the downward flow. Things have been adopted.

When the screen surface of the carrier separation device is vertically arranged, the swirling flow and the screen surface cross-flow, and the screen surface is constantly washed by the flow to reduce clogging. Are in the same direction, it is difficult to visually check the screen surface from above.

On the other hand, when the screen surface is arranged parallel to the oblique flow in the course of turning from the upward flow to the horizontal flow or from the horizontal flow to the downward flow, the screen surface is parallel to the water flow. As with the conventional structure, clogging is prevented by cross flow, but the oblique flow is obtained relatively on the side of the tank, which usually hinders maintenance from the opening provided in the upper center of the tank. May be harmful.

[0009]

DISCLOSURE OF THE INVENTION The present invention eliminates the structural problems and the restrictions on the apparatus found in the prior art, and reduces the water level of the carrier filtration tank during the filtration carrier washing by a simple method. It is a first object to provide a means for causing this to occur.

[0010] A second object of the present invention is to solve the problem of maintenance in the conventional carrier separation device, to obtain a carrier which is hardly clogged, has a stable separation action, and has good workability during maintenance. It is to provide a separating device.

[0011]

In order to solve the above-mentioned first problem, according to the present invention, the water level of the front tank 6 located on the upstream side of the flow of the sewage treatment is lowered by forced transfer. Is transferred to tanks 5 and 6 located on the upstream side to lower the water level in the carrier filtration tank, and thereafter, the filtration carrier in the carrier filtration tank is washed.

In the above means, a buffer chamber for obtaining a space necessary for washing the filter carrier is provided in the front tank 6 upstream of the processing flow.
The cleaning is performed by lowering the liquid level of the carrier filtration tank and storing the treated water in the carrier filtration tank to lower the water level in the carrier filtration tank. This makes it possible to prevent the solid material from flowing to the next tank due to the swelling of the water surface during washing with a simple system.

According to the above-mentioned means, a structure such as an air tank is not required, and the present invention can be applied to a sewage treatment apparatus having no flow rate adjusting tank.

In order to solve the second problem, according to the present invention, the filtration screen surface 21 of the carrier separating device is disposed at a central portion near the water surface of the tank, and the direction of the water flow in the water surface portion of the swirling flow in the tank. The filtration screen 24 is installed at an angle of more than 30 degrees and less than 90 degrees with respect to a horizontal plane orthogonal to the above.

Since the carrier separation device having the above structure is arranged in the center near the water surface, it is easy to visually check the state of blockage from the upper opening, and the work is easy when cleaning the screen surface with a brush or the like. It is. Furthermore, in the case of manufacturing with a ready-made pipe member or the like, since the screen area can be increased as compared with the case where the screen surface is provided horizontally, the amount of permeated water per unit area can be set low, thereby achieving a stable separation action. The effect of preventing blockage is exhibited.

In the carrier reaction tank, an upward flow is first generated by aeration, and then a horizontal flow is formed near the water surface, and a swirling flow gradually turning downward is formed. The carrier separating device is located at the center near the water surface, and has a structure in which the screen surface is washed by the horizontal flow and is hardly clogged.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in FIGS. The inside of the sewage treatment apparatus 1 of the illustrated embodiment is divided into a solid-liquid separation tank 5, an anaerobic filter bed tank 6, a carrier reaction tank 7, and a carrier filtration tank 8 by partitions 2, 3, and 4. A disinfection tank 9 is provided at the center of the upper part. In the upper part of the apparatus, a maintenance opening 10 indicated by a dotted line in FIG. 2 is provided.

The central part of the anaerobic filter bed tank 6 is filled with a filter medium 11. The carrier reaction tank 7 is filled with a carrier 12 having a specific gravity of about 1, and an air diffuser 13 is disposed at an eccentric position at the bottom. Due to the aeration from the air diffuser, a swirling flow is generated in the carrier reaction tank which rises on one side wall of the tank, flows horizontally in the upper layer portion, and descends along the opposite side wall.
The carrier floats on this swirling flow, and sewage is purified by aerobic microorganisms that have landed on the surface or inside of the carrier.

The carrier filtration tank 8 has a filtration carrier 26 having a low specific gravity.
And a diffuser 14 for washing capable of aerating a large amount of air is disposed in a portion slightly below the middle. In the normal operation state, aeration is not performed from the cleaning air diffuser, and the filtration carrier 26 is densely packed on the upper layer by buoyancy, and the treated water is deposited on the carrier while passing through the dense layer. The solid content is captured by the microorganisms that have been deposited. Filtration carrier 26
The washing is performed by aerating and flowing air from the washing air diffuser 14 as needed to separate and settle solids attached to the surface. The settled sludge is returned to the solid-liquid separation tank 5 by a sludge return pipe 15 provided with an air lift pump.

The water surface of the partition wall 2 between the solid-liquid separation tank and the anaerobic filter bed tank and the partition wall 3 between the anaerobic filter bed tank and the carrier reaction tank are:
An advection port 16 penetrating the partition wall is provided, an inflow pipe 17 of sewage is opened in the solid-liquid separation tank, and a discharge pipe 18 is provided in the disinfection tank 9. The anaerobic filter tank 6 is provided with a forced transfer pipe 19 provided with an air lift pump.
The suction port 20 of this forced transfer pipe 19 is open near the water surface of the anaerobic filter bed tank 6, and once lowers in order to obtain the required lift of the air lift pump, is guided again upward, and then is discharged again. Open at the top of the carrier reaction tank.

A partition 4 for partitioning the carrier reaction tank and the carrier filtration tank
A carrier separation device 22 having a screen surface 21 at the opening end on the carrier reaction layer side is provided directly below the water surface. This carrier separation device is disposed at the center of the carrier reaction tank 7 near the water surface, and the open end on the carrier reaction tank side is parallel to the water flow in the tank at the opening portion and 30 ° with respect to the horizontal plane. A screen 24 having a large number of horizontally elongated filtration holes 23 is attached to the diagonally cut surface at an angle of 45 to 45 degrees.

This screen is located just below the water surface of the carrier reaction tank, and the swirling flow of the carrier reaction tank generated by the aeration of the diffuser 13 causes the filtration holes of the screen to pass through as shown by arrows in FIG. 23 flows in the longitudinal direction. The end of the carrier separation device 22 on the side of the carrier filtration tank 8 is opened just below the water surface of the carrier filtration tank during normal operation.

During normal operation, the air lift pump of the forced transfer pipe 19 and the aeration of the cleaning air diffuser 14 are stopped. The raw water flowing into the solid-liquid separation tank 5 is supplied to the advection port 16,
After 16, the water overflows through the anaerobic filter bed tank 6 to the carrier reaction tank 7. In the carrier reaction tank 7, the treated water is purified by the aerobic microorganisms that have landed on the carrier 12, and the screen 24 is cleaned.
The treated water from which the carrier has been separated flows into the carrier filtration tank 8. Then, filtration is performed on the carrier 26 of the carrier filtration tank,
Released through the disinfection tank. The filtered sludge settled at the bottom of the carrier filtration tank 8 is returned to the solid-liquid separation tank 5 by operating the air lift pump of the sludge return pipe 15 as appropriate.

The washing of the carrier 26 in the carrier filtration tank is performed in consideration of a time period during which raw water does not flow, such as at night. First, the air lift pump of the forced transfer pipe 19 is operated to forcibly transfer the sewage in the anaerobic filter bed tank 6 at a flow rate not exceeding the processing capacity of the carrier reaction tank 7. Thereby, the water level of the anaerobic filter bed tank 6 decreases. Next, the air lift pump of the sludge return pipe 15 is operated to return the treated water in the carrier filtration tank 8 to the solid-liquid separation tank 5. The returned treated water overflows into the anaerobic filter bed tank 6, but does not flow into the carrier reaction tank because the water level in the anaerobic filter bed tank 6 has been lowered in advance. As a result, the water level in the carrier filtration tank 8 decreases, so that a large amount of air is aerated from the cleaning air diffuser 14 to wash the filtration carrier 26. The sludge separated and settled by the washing is returned to the solid-liquid separation tank 5 by the sludge return pipe 15.

This cleaning process is performed for a time set by a timer or the like. When the cleaning is completed, the operation returns to the normal operation.

The screen surface 21 of the carrier separation device 22
The maintenance opening 10 at the top of the apparatus can be opened and visually recognized. If sludge adheres, clean the screen by inserting a brush through the opening. Whether or not sludge on the screen surface has been removed can be easily confirmed from the opening.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of a sewage treatment apparatus according to an embodiment.

FIG. 2 is a cross-sectional plan view of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a sectional view of a carrier separation device.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 schematically shows a conventional apparatus.

[Explanation of symbols]

 5 Solid-liquid separation tank 6 Anaerobic filter bed tank 7 Carrier reaction tank 8 Carrier filtration tank 12 Carrier 14 Cleaning diffuser tube 19 Forced transfer tube 21 Screen surface 22 Carrier separation device 26 Filtration carrier

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroshi Yamazaki 3-92 Nishiizumi, Kanazawa-shi, Ishikawa F-term (reference) within AMS Corporation 4D003 AA12 AB02 BA02 CA02 CA03 CA08 DA09 DA11 EA01 EA28 4D027 AA01 AA02 AA12 AA14 AB06 AB07 AB12 AB14

Claims (2)

[Claims] 1. A carrier filtration tank (8), which is filled with a filtration carrier (26) to perform solid-liquid separation, and is periodically aerated by aeration.
6) Cleaning air diffuser to remove trapped suspended matter by cleaning
In the sewage treatment apparatus provided with (14), a forced transfer device (forcibly transferring the treated water from the front tank (6) located on the upstream side of the flow of the treated water to the next tank (7) located on the downstream side) Before the washing of the filter carrier (26), the forced transfer device (19) is operated to lower the water level of the front tank, and then the water in the carrier filtration tank (8) is located upstream of the tank (5). Sewage treatment apparatus for washing the filtration carrier (26) after lowering the water level of the carrier filtration tank (8) by sending it to the carrier filtration tank (8). 2. A carrier reaction tank (7) for filling a carrier (12) and blowing a gas containing oxygen to swirl the filled carrier to purify waste water, and a carrier (7) from the carrier reaction tank to the next tank. 1
In a sewage treatment device provided with a carrier separation device (22) for separating 2) and transferring treated water, a screen surface (21) is placed on a horizontal surface at a site where a horizontal flow is caused in the carrier reaction tank (7). Carrier separation device at an angle of more than 30 degrees and less than 90 degrees
A sewage treatment apparatus provided with (22).