JPS60232292A - Sewage treatment appratus - Google Patents

Abstract

PURPOSE:To certainly perform the treatment of sewage, by providing a plurality of treatment tanks in change-over possible manner and allowing sewage to flow into the other tank held under a stationary state when the inflow amount of sewage exceeds predetermined value. CONSTITUTION:Treatment tanks A, B repeating aeration, precipitation and discharge processes at every predetermined time are mutually shifted in a process phase so that either one of them takes the aeration process and the other one takes the precipitation or discharge process. Sewage (a) to be treated in successively flowed into the tank performing aeration at a usual time by a sewage supply apparatus 14 to perform usual batchwise activated sludge treatment. When the inflow amount of sewage reaches a set value or more on account of the rain, sewage is flowed into the other tank from the communication port 1 provided to the tank wall of a prereactor part 3 so as to be opened above HWL. The treatment tank is partitioned into the prereactor part 3 and a main reactor part 4 by a buffle 2 to prevent the shortcircuit of untreated sewage.

Description

[Detailed Description of the Invention] This invention is normally applied to batch-type activated sludge treatment in which wastewater is treated by repeating the steps of aeration, precipitation, and discharge in a treatment tank. The present invention relates to a sewage treatment device that can effectively treat sewage even when

Among the activated sludge treatment methods that have become mainstream in domestic wastewater treatment in recent years, batch-type activated sludge treatment involves repeating the steps of aeration, precipitation, and discharge in a treatment tank that receives sewage continuously or at any time. Sludge treatment equipment is attracting attention.

Batch-type treatment equipment has traditionally been used mainly when wastewater flows in only during operating hours (e.g. 8 hours), such as when wastewater is discharged continuously, such as sewage. It is also being applied to processing. and,
In such cases, a plurality of treatment tanks are provided, and the untreated wastewater is prevented from being discharged as it is by sequentially flowing into the cypress where the aeration treatment is being performed.

However, in the case of sewage, not only in a combined system, but even in a separate system, rainwater flows in during rainy days, so the amount of inflow water is quite large.

Therefore, unless the tank capacity is determined in accordance with the maximum amount of inflow during rainy weather, the amount of inflowing water will be too large during rainy weather and will overflow from the cypress. However, if the tank capacity is determined in this way, the tank capacity will become extremely large, making it unrealistic.

The present invention solves the above-mentioned drawbacks and provides a sewage treatment device that can reliably treat sewage by allowing the sewage to flow into another stationary tank even if the amount of sewage inflow exceeds a set value. With the goal.

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, this invention is a 4% treatment #A that is provided with a plurality of (two tanks in this example) in which each step of aeration, precipitation, and discharge is repeated at predetermined time intervals.

B (hereinafter referred to as A tank and B tank), and a sewage switching unit 1 that sequentially switches and causes sewage to flow into each person and the B tank.

The above tanks A and B are shown in Figure 3 (Figure 3 (A) shows each process procedure diagram of tank A, and Figure 3 (B) shows the same procedure diagram of tank B). When one is an aeration process, the other is a precipitation or discharge process, so it is preset that the processes are carried out out of phase with each other. The inside of the B cypress is divided into a prereactor section 3 and a main reactor section 4 by a baffle 2, and this A
The tank and B calibration are connected through a communication port (sewage switching section) 1 opened in the tank wall above H, W, and L. Also,
As shown in FIG. 2, an aeration device 5 is provided at the bottom of tanks A and B for blowing air from an aeration blower (not shown) into the wastewater during the aeration process.

An automatic decanter 6 is disposed at the top of the tank to discharge the supernatant during the discharge process following the precipitation process. This automatic decanter 6 includes a discharge pipe 8 connected to a rotatable shaft pipe 7, an overflow pipe 9 attached to the free end of the discharge pipe 8 and having an overflow port 9, and a scum baffle. It is composed of flow number O. And overflow pipe 9
When the water is at the water surface, the supernatant water in tanks A and B flows into the overflow pipe 9 through the overflow port 9a, and is discharged to the outside through the shaft pipe 7. Furthermore, when the overflow pipe 9 is rotated by the rotation means 11 so as to be at a position higher than the liquid level, the liquid in the tank is not drained.

In addition, the supply of wastewater a to tank A and tank B is as follows, for example.

This is carried out by a waste water supply device 14 consisting of a pump bit 12 and a pump 13.

Next, operation 1 of the present invention will be explained.

The sewage a to be treated is sequentially flowed by the sewage supply device 14 into one tank A or B which normally performs aeration, and in each type A or B, aeration is performed by the aeration device 7, sedimentation is performed by standing still, and a decanter is performed. 6 is sequentially discharged as shown in FIG. 3, and normal bulk activated sludge treatment is performed.

Next, in the event of an abnormality, for example, when the amount of sewage inflow exceeds the set value during rainy weather, sewage flows into the other tank from the communication port 1 opened above H, W, and L of the pre-reactor 3 tank walls. Inflow. For example, if the amount of sewage flowing into tank A is abnormally large, the water level rises and reaches the position of communication port 1, and the sewage in tank A flows into tank B. Here, since the B tank is in the sedimentation or discharge process (in this example, the discharge process, see FIG. 3 (B)) as described above, the wastewater a flowing from the A tank is precipitated from the prereactor part 3. Upon contact with the activated sludge, pollutants in the wastewater are adsorbed by the activated sludge, purified, and then discharged.

At this time, if the prereactor section 3 is normally not aerated or stirred (aerating may be performed intermittently to prevent solid matter accumulation), the activated sludge from the A cypress will not flow into the B tank. , there will be no problem with subsequent processing. Further, since the treatment tank is divided into a pre-reactor section 3 and a main reactor section 4 by the baffle 2, untreated wastewater will not be discharged in a short circuit.

Therefore, according to this embodiment, even if a larger amount of sewage flows in than rainwater or the like, it can be treated without any problems, and the quality of the treated water is unlikely to deteriorate. In addition, since rainwater and the like have low BOD, etc., sufficient treatment can be performed by contact with activated sludge and sedimentation treatment in a stationary treatment tank.

FIG. 4 shows another embodiment using a pump as the wastewater switching section. In this embodiment, a first pump 15 causes the mixed liquid in tank A to flow into the prereactor section 3 of tank B, and a second pump 16 causes the mixed liquid in tank B to flow into the prereactor section 8 in tank A. The waste water switching section is configured by:

Therefore, for example, when wastewater flows into the λ tank, when the amount of inflow water exceeds a predetermined amount, the aerated liquid mixture in tank A is transported to tank B by the first pump 15, and the water level in Al1 exceeds a certain value. Try not to get too excited. On the other hand, the mixed liquid flowing into tank B is treated here as described above, and the supernatant liquid is discharged.

At a predetermined time, tank B starts the aeration process, wastewater flows into tank B, and normal treatment takes place. here,
As in the previous case, when the amount flowing into tank B exceeds a predetermined amount, the second pump 16 transfers the mixed liquid from tank B to tank A, where it is processed in the same way.

In this case, sometimes the MLSS of one type of cypress is significantly lower than that of the other type. In preparation for such a case, measure the MLSS of both tanks, and if the difference is above a certain level (at the start of aeration, the water level is always W and L, so it is a good idea to compare the MLSS values at this time) , by pumping,
Eliminate that difference.

In this case, the aerated mixture may be transported, or the settled sludge may be transported.

Therefore, according to this embodiment, normal activated sludge treatment can be carried out even if a large amount of wastewater flows in.

The sewage switching section is not limited to the above-mentioned means of inflowing one type of liquid in the tank to another, but may also switch the inflow of sewage itself by switching the sewage supply device 14. Further, in the above embodiment, the case where the treatment tank has two cypresses has been described, but the treatment tank is not limited to this, and may be three or more cypresses.
It is only necessary to allow a predetermined amount or more of wastewater to flow into the cypress in a stationary state.

As described above, according to the present invention, even if the amount of sewage inflow exceeds a predetermined value, the sewage can be reliably treated by flowing the sewage into other cypresses in a stationary state. has.

[Brief explanation of drawings]

Fig. 1 is a plan view of an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view of the same, Fig. 3 (A) is a procedural diagram of each process of A-cypress wood, Fig. 3 (
B) shows the same procedure diagram of tank B, and FIG. 4 shows a plan view of another embodiment. A, B...Treatment tank, I, 15.16...Sewage switching section.

Claims (1)

[Claims] It is equipped with two or more treatment tanks that repeat the steps of aeration, sedimentation, and discharge at predetermined intervals, and a wastewater switching section that sequentially switches and flows wastewater into each of the treatment tanks, and at least one of the treatment tanks is used for sedimentation or discharge. If the inflow of sewage into another treatment tank exceeds a certain amount within a predetermined period of time, the excess sewage is sedimented or transferred to the treatment tank in the discharge process via the sewage switching section. A sewage treatment device characterized by the introduction of the system.