JPS59115788A - Method and device for treating sewage - Google Patents

Abstract

PURPOSE:To clean up sewage at a high rate of cleaning by using a device combining a catalytic aeration method utilizing aerobic bacteria and an activated sludge method in treating the sewage thereby making use of the advantages that both methods possess. CONSTITUTION:Sewage is once put into a storage and control tank 1 and is lifted by pumps 5, 6 into a measuring inlet 2. The sewage is supplied at the controlled flow rate from the inlet 2 into the 1st tank of plural consecutive aeration tanks 3; at the same time, the air is delivered by blowers 7, 8 and is blown through a diffusion port 9 into the sewage. The sewage flows through filter media 10 on which aerobic microorganisms stick and the pollutant in the sewage is oxidized and decomposed by the microorganism. Such operation is repeated in each tank 3 and thereafter the sewage is put into a settling tank 4 where sludge is settled and the activated sludge contg. a large amt. of the aerobic bacteria is returned by a return device 12 into the the tank 3 where the sludge is reused. The supernatant water is released after it is passed through a post treatment stage according to need.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sewage treatment method that organically combines a contact aeration method using the action of aerobic microorganisms and an activated sludge method, and an apparatus therefor.

Sewage treatment using the action of aerobic microorganisms provides sufficient oxygen to microorganisms that use organic matter contained in wastewater as a nutrient source,
This method promotes this activity and oxidizes and decomposes pollutants, and is conventionally known as the contact aeration method.

Various methods were known, including the activated sludge method.

In this contact aeration method, wastewater that has flowed into an aeration tank is oxidized by being brought into contact with aerobic microorganisms living on the surface of the filter medium placed in the tank, and the range of activity of aerobic microorganisms is Since there is a limited amount of wastewater, it is necessary to treat when there is little inflow of wastewater.

Although it is suitable for treatment when the BOD concentration is low, it is unsuitable for the opposite case, that is, when there is a large amount of inflowing sewage and the BOD concentration is high, or for the treatment of sewage containing a large amount of oils and fats. On the other hand, the activated sludge method

Sludge containing a large amount of aerobic microorganisms is suspended in wastewater in an aeration tank, mixed with air by a blower, and brought into contact with aerobic microorganisms for oxidation treatment, which increases the activity of aerobic microorganisms. Therefore, even when there is a large amount of inflowing wastewater, it is resistant to high concentrations of BOD loads, but on the other hand, excessive aeration disrupts the nutrient-organism balance and reduces the purification rate. There has been a problem in that the so-called swelling phenomenon, which is a decrease in the amount of water, tends to occur.

In view of the above points, this invention takes advantage of the advantages of the contact aeration method and the activated sludge method, eliminates their disadvantages, and disassembles aerobic microorganisms.

The object of the present invention is to provide a sewage treatment method and apparatus that eliminate swelling, improve purification efficiency and settling power, and stably obtain effluent of good quality.

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

1 is an adjustment tank for storing wastewater discharged from a wastewater source (not shown), 2 is a measuring cell, 3 is an aeration tank, and 4 is a settling tank.

There are a plurality of pumps 51 (the figure shows two pumps, but there may be more) in the adjustment tank l.
, 6 are arranged to pump up wastewater into the measuring cell 2. The measuring cell 2 is used to adjust the amount of sewage flowing into the aeration tank 3, and depending on the device, such adjustment may be performed by the pump itself, and the measuring cell 2 may not be installed. Although the figure shows a case where three types of aeration tanks 3 are installed in succession, the aeration tank 3 is not limited to this. Each type of aeration tank 3 is provided with a filter medium 10 for adhering aerobic microorganisms. In addition, for each type, atmospheric air is supplied from multiple blowers 7 and 8 (two blowers are shown in the figure, but more may be used) through a discharge port 9 installed in the tank. It is now possible to do so. This air supply is necessary in order to provide sufficient oxygen to the aerobic microorganisms living on the surface of the filter medium and the returned activated sludge, which will be described later, to promote the reproduction of the aerobic microorganisms and to activate their activities. The sewage that has been sufficiently aerated in the aeration tank 3 is sent from the upper part of the tank to a settling tank 4, where it is sedimented and separated, and the supernatant water is discharged after undergoing a post-treatment process if necessary. On the other hand, since the settled sludge contains a large amount of aerobic microorganisms, it is returned to the aeration tank 3 in which the filter medium is arranged via a return device 19.

The two pumps 5 and 6 arranged in the regulating tank 1 are operated by a float switch (not shown) when the inflowing wastewater reaches a reference water level. Further, the blowers 7 and 8 are driven in conjunction with the pump 5.6. The blowers 7 and 8 can continue to operate for a certain period of time even after the pumps have been stopped by the action of an electronic timer (not shown).

The extended time of this blower depends on how the electronic timer is set, but it can be made longer or shorter depending on the amount of inflow of sewage and the amount of BOD load. In most cases, this cent time of about 30 minutes to 1 hour is satisfactory.

Further, one or both of the blowers 7 and 8 are operated at regular intervals by a timer (not shown) separately from the float switch. This is because, depending on the load of inflowing sewage, it may be necessary to operate the blower at regular intervals several times a day, or to operate one blower continuously for 24 hours.

In addition, 11 in Fig. 3 is a fourth aeration tank, and the fourth aeration tank 11 is a preliminary tank for further aerating the supernatant water of the sediment layer 4, and like the aeration tank 3, it is used to attach aerobic microorganisms. The filter medium 10 is provided with an air outlet 9 that communicates with the blowers 7 and 8, and a hasoflu 13 is installed to prevent the supernatant water from stirring. This fourth aeration tank 11 does not necessarily have to be provided.

As described above, the present invention is as follows: wastewater flowing into an aeration tank from a regulating tank via a pump is placed in the tank, passes through a filter medium, contacts aerobic microorganisms living on the surface of the tank, and is then aerated. Since the sludge that has been settled and separated in the settling tank is returned to the aeration tank in which the filter medium is placed, the i-air tank contains aerobic microorganisms living on the surface of the filter medium as well as aerobic microorganisms that are returned together with the sludge. It will be filled with.

The aerobic microorganisms floating in this tank become active and adsorb and oxidize pollutants by supplying the necessary oxygen, but they are originally living organisms and have a limited oxidizing ability, so they usually disintegrate and expand. If microorganisms that limit the oxidizing ability adhere to the surface of the filter media placed in the tank, the microorganisms with the oxidizing ability on the surface of the filter media may As a result, the inside of the tank will be maintained by microorganisms with high oxidizing ability.

Therefore, according to the method and device of the present invention, even if the amount of sewage is large or the BOD load is high, the amount of sewage can be concentrated or disappear depending on the time of day, season, etc. Even in such cases, it is compatible with all site conditions and has the excellent effect of stably obtaining effluent water of good quality.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing an embodiment of the present invention, and includes: 1--adjustment tank, 3-aeration tank, 5.6-pump,
7.8-Prower-9-・Return device, 1
0-Filter agent agent Patent attorney Yuki Hamura Ko procedure Neho (method) April 28, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of case 1988 Patent application No. 230315 2- Invention Name of sewage treatment method and its device 3 - Relationship with the case of the person making the amendment Patent applicant address 4-383 Tokoji-cho, Kofu City, Yamanashi Prefecture Name Small
Hidenori Hayashi 4 - Agent ■ 151 Address 6-2-5-1 Yoyogi, Shibuya-ku, Tokyo - Application and specification subject to amendment 7 - Contents of amendment

Claims (1)

[Claims] (After the sewage that flows into the aeration tank from the 11-open adjustment tank via a pump passes through a filter medium placed in the tank and comes into contact with aerobic microorganisms living on the surface of the tank, it is aerated. A sewage treatment method characterized by returning the sludge that has been settled and separated in the settling tank to an aeration tank in which the filter medium is arranged. (2) An aeration tank in which a filter medium is arranged for adhering aerobic microorganisms, and the aeration tank. It is characterized by comprising a settling tank that sediments and separates sewage after aeration in the tank, and a return device that returns the sludge containing aerobic microorganisms settled in the settling tank to the aeration tank in which the filter medium is arranged. sewage treatment equipment.