JP2520571B2 - Septic tank with flow rate adjustment device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a septic tank equipped with a flow rate adjusting device.

[0002]

2. Description of the Related Art Recently, a small-scale combined treatment septic tank having, for example, 50 or less persons to be treated has rapidly spread as a treatment facility for domestic domestic wastewater. Since this type of combined treatment septic tank is more effective in reducing the pollution load than the single treatment septic tank, it is considered to be an extremely effective sewage treatment facility for the treatment of household wastewater caused by discharge from households. ing.

The conventional combined treatment septic tank 11 as described above is
It is configured as shown in FIG. That is, the raw water (sewage) as domestic wastewater is first sent from the anaerobic filter bed first chamber 52 to the anaerobic filter bed second chamber 53 in a cascading manner for filtration treatment, and then the biofilm treatment tank 54. Sent to. There, the organic matter is removed from the raw water by passing through the space between the carriers, stored once in the treated water tank 55, and then discharged as transparent treated water to the outside of the system. When necessary, the backwash water is sent to the biofilm treatment tank and the anaerobic filter bed tank by the backwash pump to backwash the filter medium therein.

[0004]

However, since the domestic wastewater has a peak depending on the time of the day, for example, in the morning and evening, and the flow rate thereof fluctuates greatly, the treatment performance of the domestic wastewater is greatly reduced at the peak. At present, many purification facilities are seen.

Therefore, it is an object of the present invention to provide a septic tank in which a flow rate adjusting device for adjusting the fluctuation of the amount of waste water is incorporated in the septic tank to make the flow rate of the waste water uniform and to improve and stabilize the treatment performance.

[0006]

In the septic tank of the present invention, an anaerobic filter bed tank, a biofilm treatment tank, and a treated water tank are sequentially arranged, and the anaerobic filter bed tank and the biofilm treatment tank are provided between the anaerobic filter bed tank and the biofilm treatment tank. A flow rate adjusting device is arranged and a circulation device for circulating the treated water from the treated water tank to the anaerobic filter bed tank is provided.

[0007]

In the septic tank of the present invention, the flow rate of the raw water from the anaerobic filter bed tank is adjusted by the flow rate adjusting device according to the fluctuation of the raw water flowing into the biofilm treatment tank, and the water is treated by the aerobic microorganisms therein. The treated water is made into transparent treated water, stored in the treated water tank and discharged to the outside of the system, and a part of the treated water is circulated to the anaerobic filter bed tank by the circulation device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a septic tank equipped with the flow rate adjusting device of the present invention will be described with reference to FIGS.

First, the principle of flow rate adjustment of the septic tank flow rate adjusting apparatus of the present invention will be described with reference to FIGS.

As shown in FIG. 1 (a), the vertical axis represents the flow rate of domestic wastewater (l) and the horizontal axis represents the time zone (24 hours).
Domestic wastewater (dirt water) fluctuates greatly depending on the time of day, resulting in deterioration and instability of the treatment performance of wastewater treatment facilities such as septic tanks. Therefore, in the present invention,
By means such as that described later, the fluctuation of the amount of wastewater is adjusted to make the treated amount uniform, and as shown in FIG. 1 (b), the amount of wastewater to be treated is made uniform (adjusted so that it does not vary depending on the time period). ) Do.

Therefore, in the present invention, the combined treatment septic tank 1 is constructed as shown in FIG. That is, for example, the anaerobic filter bed first chamber 2 and the anaerobic filter bed second chamber 3 filled with a reticulated cylindrical polyethylene resin filter medium, the aerobic biofilm treatment tank 4 filled with a porous ceramic carrier, and treated water The treated water tank 5 for storing once is connected in a cascade form.

In the anaerobic filter bed tanks 2 and 3, mainly SS components (floating substances) are removed and purification by anaerobic organisms is performed, and in the second chamber 3 of the anaerobic filter bed, an intermittent metering pump as a flow rate adjusting device is provided. It is provided and supplies a fixed amount of water to the biofilm treatment tank 4 to reduce fluctuations in the flow rate. That is, the anaerobic filter bed tanks 2 and 3 are divided into two chambers, and have an adjusting capacity for, for example, 7 hours with respect to the average daily sewage amount in order to eliminate the fluctuation of the inflow sewage (raw water) flow rate. The treated water treated in the anaerobic filter bed tanks 2 and 3 is always quantitatively fed to the biofilm treatment tank 4 by, for example, an air-driven intermittent metering pump, so that the flow rate of raw water (sewage) is not changed. It will be made uniform.

In the biofilm treatment tank 4, swimsuit / decomposition and physical filtration by aerobic microorganisms adhering to the porous ceramics carrier are carried out to obtain transparent treated water.

The treated water tank 5 is provided with a backwash pump and a circulation device, and the backwash water is sent to the biofilm treatment tank 4 and the anaerobic filter bed first chamber 2 by this backwash pump. Then, the back-washing of these filter media is performed, and the circulating water in the tank is sent to the anaerobic filter bed first chamber 2 by the circulation device.

Here, the flow rate (N) returned from the treated water tank 5 to the anaerobic filter bed first chamber 2 as the circulating water in the tank is N = 3 to 5 with respect to the raw water inflow amount 1, so a flow rate adjusting device ( The amount of raw water fed from the anaerobic filter bed second chamber 3 to the biofilm treatment tank 4 is 1 + N by the intermittent metering pump). Therefore, the amount of treated water sent from the biofilm treatment tank 4 to the treated water tank 5 is 1 + N.
Since N amount of treated water is circulated as circulating water,
Eventually, the amount of treated water discharged will be 1.

Next, an embodiment of a septic tank to which such a flow rate adjusting principle of the flow rate adjusting device of the present invention is applied is shown in FIGS.
It will be described based on.

As shown in FIG. 3, the septic tank 1 of this embodiment
Is configured by connecting an anaerobic filter bed first chamber 2, an anaerobic filter bed second chamber 3, a flow rate adjusting tank 4 and a treated water tank 5 in a cascade form. Raw water to be treated (household wastewater, sewage) flows from the inflow pipe 6 into the anaerobic filter tanks 2 and 3, and is quantitatively fed to the aerobic biological treatment tank 4 which is sandwiched between the adjusting tanks 41 and there. The water is treated while flowing down between the carriers 42, is temporarily stored in the treated water tank 5, and is then discharged out of the system through the discharge pipe 7 as transparent treated water. The septic tank 1 is normally buried below the surface of the earth (GL), and is installed on the floor (FL) via the underframes 11a and 11b, and the inside of the septic tank is monitored via the manholes 12a, 12b and 12c. It can be inspected.

A cylindrical casing 21 is arranged at the axial center of the anaerobic filter bed first chamber 2, and a net-like cylindrical polyethylene resin (PE) is used as a filter medium 22 in the casing 21.
Many filter media are filled.

Further, a baffle plate 20 is arranged immediately below the inflow pipe 6 to give a baffle effect to the inflowing raw water.

An anaerobic filter bed tank second chamber 3 is adjacent to the anaerobic filter bed tank first chamber 2 via a partition plate 8. Similar to the anaerobic filter bed tank first chamber 2, a cylindrical casing 31 is disposed in the axial center portion of the anaerobic filter bed tank second chamber 3, and a polyethylene resin having a reticulated cylindrical shape is provided as a filter medium 32 in the circle. A large number of (PE) filter media are filled. The raw water that has been anaerobically treated in the anaerobic filter bed first chamber 2 passes through the advection port 15a provided on the anaerobic filter bed first chamber 2 side through the advection weir 15b above the partition plate 8 to the anaerobic filter bed tank. The advection port provided in the second chamber 3 is adapted to flow into the inside of 15c.

Further, a biological membrane treatment tank (aerobic biological filtration) which is adjacent to the second chamber 3 of the anaerobic filter bed and which is filled with a large number of porous ceramics carriers 42 (for example, Hypermix, trade name, particle size 2-15 mm). Tank) 4 is provided.

The biofilm treatment tank 4 is formed by being divided by the partition plates 9 and 10 from the anaerobic filter bed second chamber 3 and the treated water tank 5, and is partitioned by a partition wall 46 as shown in FIG. Spaces are formed on both sides of the flow rate adjusting tank 4
1 is defined.

Raw water from the anaerobic filter bed second chamber 3 is admitted to the admission port 1
5c, 15c flow into the flow rate adjusting tanks 41, 41, and the check valves 32b, 32b whose opening can be adjusted are delivered to the partition plate 9 between the anaerobic filter bed second chamber 3 and the flow rate adjusting tank 41, The flow rate of raw water transferred to the flow rate adjusting tanks 41, 41 can be adjusted.

The two flow rate adjusting tanks 41, 41 are connected to each other at their bottoms by a communication pipe 32a. As a result, the water levels of both flow rate adjusting tanks 41, 41 are kept the same.

As shown in FIGS. 4 and 5, an intermittent metering pump 14a (see, for example, Japanese Utility Model Laid-Open No. 63-110699) is installed in each of the flow rate adjusting tanks 41, and a water pipe 14a 'is used. Therefore, the raw water in the second chamber 3 of the anaerobic filter bed is quantitatively and intermittently crossed over the partition wall 46 to obtain the biofilm treatment tank 4
It is designed to send water to. In addition, 14d is an air tube of the intermittent metering pump 14a. A metering weir may be used instead of the intermittent metering pump.

Further, immediately below the support layer 43 of the biofilm treatment tank 4, an air diffuser 16b and a backwash pipe 13b for diffusing air into the tank 4 are provided, and a diffuser pump (not shown) is provided. It is connected to each backwash pump 13a through another backwash pipe 13c. Further, a treated water return air lift 14b is provided upright in the vicinity of the backwash pump 13a and the air lift piping 14 is provided.
The treated water in the treated water tank 5 is transferred via the c to the anaerobic filter bed first chamber 2
It is configured to recirculate as circulating water in the tank. A circulating pump may be used instead of the air lift to circulate the circulating water.

Next, a disinfecting tank 51 is provided at the outlet end of the treated water tank 5, and the treated water is disinfected by the disinfectant from the chemical cylinder 52 to give transparent treated water from the discharge pipe 7. It is designed to be released outside.

Next, an example of the operation of the embodiment of the septic tank of the present invention configured as described above will be described with reference to FIG.

First, the raw water flowing from the inflow pipe 6 into the anaerobic filter bed first chamber 2 of the septic tank 1 adheres to the filter medium 22 while flowing down between the filter medium 22 from the upper portion to the lower portion thereof as shown by the arrow. After being treated and purified by the anaerobic microorganisms stored and stored at the bottom of the anaerobic filter bed first chamber 2, it flows in through the inlet of the advection port 15a and extrudes through the advection weir 15b into another advection port 15c. To the anaerobic filter bed second chamber 3 from its outlet. Then, after being treated by another filter medium 32, water is sent to the biofilm treatment tank 4 through the check valve 32b by an extrusion flow method. Further, when the raw water flows in and the water level in the second chamber 3 of the anaerobic filter bed rises, the raw water flows down to the flow rate adjusting tanks 41, 41 over the advection port 15c located above the check valve 32b. Therefore, the raw water is supplied to the intermittent metering pump 14a provided in the flow rate adjusting tank 41.
The water is supplied to the biofilm treatment tank 4 via the water supply pipe 14a 'in a fixed time and intermittent manner.

In the biofilm treatment tank 4, raw water is flown downward by the aerobic microorganisms adhering to the porous ceramics carrier 42 between the carriers 42 while the substrate therein is diffused by the aeration pipe 16b.
Decomposed into CO ₂ and H ₂ O by oxygen supplied from
Raw water is purified by the two functions of biological contact oxidation and physical filtration to obtain treated water.

The purified treated water then flows into the treated water tank 5, is sterilized, and is discharged out of the system through the discharge pipe 7 as transparent treated water.

The anaerobic filter bed first chamber 2 and the second chamber 3
In addition, when backwashing of the filter media 22 and 32 and the porous carrier 42 filled in the biofilm treatment tank 4 is necessary, the backwash pump 1
The backwash water is supplied from the treated water tank 5 that drives 3a.
Water is back-washed from the lower part of the carrier 42 of the biofilm treatment tank 4 by b and 13c. Further, the backwash water is replaced with another backwash pipe 1
By 3d, water is supplied to the first chamber 2 and the second chamber 3 of the anaerobic filter bed to backwash the filter medium therein.

[0033]

As described above, the septic tank equipped with the flow rate adjusting device of the present invention can intermittently and quantitatively adjust the flow rate of the raw water by the intermittent metering pump to feed the raw water to the biofilm treatment tank. Is extremely stable and sophisticated, and the circulation of treated water dramatically improves not only nitrogen removal but also organic matter removal performance and treated water transparency. Furthermore, by setting the optimum circulation ratio of the circulation treatment, higher nitrogen removal performance can be obtained, and by using the porous ceramics carrier in the biofilm treatment tank, sufficient catalytic oxidation and physical filtration can be performed. As a whole, the tank volume of the septic tank can be made compact and the power consumption can be saved.

[Brief description of drawings]

[Fig. 1] Inflow pattern of sewage (raw water) into a septic tank (Fig. 1
(A)) and the diagram which shows the pattern (FIG.1 (b)) after the flow control of the waste water (raw water) by the flow control apparatus of this invention.

FIG. 2 is a schematic diagram showing the principle of flow rate adjustment of the septic tank of the present invention.

FIG. 3 is a vertical cross-sectional view of an embodiment of a septic tank to which the flow rate adjusting principle of the flow rate adjusting device of the present invention is applied.

FIG. 4 is a cross-sectional view of the septic tank shown in FIG. 3, taken along the line IV-IV.

5 is a partially cutaway plan view of the septic tank shown in FIG.

FIG. 6 is a schematic diagram showing the flow of raw water and treated water in a conventional septic tank.

[Explanation of symbols]

 1 Septic tank 2 Anaerobic filter bed first chamber 3 Anaerobic filter bed second chamber 4 Biofilm treatment tank 5 Treated water tank 6 Inflow pipe 7 Discharge pipe 8 Partition plate 9 Partition plate 10 Partition plate 12a, 12b, 12c Manhole 13a Backwash Pump 13b Backwash pipe 13c Backwash pipe 13d Backwash pipe 14a Intermittent metering pump (flow rate adjustment device) 14b Treated water return air lift 15a Advection port 15b Advection weir 15c Advection port 22 Filter medium 32 Filter medium 41 Flow rate control tank 42 Porous ceramic carrier 46 partition wall 51 disinfection tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-245897 (JP, A) JP-A-4-108597 (JP, A) JP-A-4-367793 (JP, A) JP-A-5- 253587 (JP, A) JP-A-5-253595 (JP, A) Actually opened 64-48198 (JP, U) Actually opened 4-37596 (JP, U)

Claims (5)

(57) [Claims] 1. A septic tank in which an anaerobic filter bed tank, a biofilm treatment tank, and a treated water tank are sequentially arranged from the raw water inflow side, wherein the biofilm treatment tank is partitioned by two partition walls. And a space provided on both sides of the treated water tank as a flow rate adjusting tank, and a flow rate adjusting device for adjusting the transfer rate of the raw water from the anaerobic filter bed tank is provided in the flow rate adjusting tank. A septic tank provided with a circulation device for circulating treated water to the anaerobic filter bed tank. 2. The septic tank according to claim 1, wherein the flow rate adjusting device is an intermittent metering pump. 3. The flow control device is a metering weir.
The described septic tank. 4. The septic tank according to claim 1, wherein the biofilm treatment tank is filled with a porous ceramics carrier. 5. The septic tank according to claim 1, wherein the circulation device is an air lift, which is provided upright in the treated water tank and communicates with the anaerobic filter bed tank through an air lift pipe.