JPS5930156B2 - wastewater treatment equipment - Google Patents

Description

Detailed Description of the Invention The present invention supplies various types of wastewater such as sewage to a treatment tank, and forms a fluidized bed of small carriers with microorganisms for wastewater treatment attached to the surface in the treated wastewater. The present invention relates to a wastewater treatment system that reduces the contact area between microbes and microorganisms, reduces the biochemical oxygen demand of wastewater, and simultaneously removes organic carbon and nitrogen from wastewater.

According to the above-mentioned wastewater treatment equipment, the contact area between the treated wastewater and microorganisms per unit volume is extremely large compared to the case where microorganisms are simply suspended in wastewater, and the treatment capacity is high (expected). However, in reality, it was not possible to obtain the high processing power that was expected.

The purpose of the present invention is to investigate the cause of such a situation and make full use of the excellent wastewater treatment function of the fluidized bed of small carriers. A fluidized bed of carriers is formed in both of the treated wastewater channels, which are formed by a deep downward flow section and an upward flow section connected below the deep downward flow section, and the small carriers are removed from each of the two fluidized beds. The small carriers regenerated by the attached microorganism detachment device and specific gravity sorting device connected by a pipe are
It is characterized in that a regenerator is attached to supply each of the fluidized beds.

In other words, when we investigated the cause of the insufficient improvement in treatment capacity in the conventional equipment considering the increase in the contact area between microorganisms and wastewater per unit volume, we found that the amount of dissolved oxygen required for their activity is insufficient compared to the amount of microorganisms. They found that the cause was the inability to increase the amount of dissolved oxygen necessary for microbial activity.Based on this point of view, by simply forming deep wastewater channels, it was possible to extremely increase the amount of dissolved oxygen necessary for microbial activity. We were able to fully demonstrate the excellent wastewater treatment function by forming a fluidized bed of the small carriers to which the microorganisms were attached, and we were able to purify wastewater in a short time with the expected high treatment capacity.

In particular, since the fluidized bed is formed in both the descending and ascending fluid sections, it is possible to effectively utilize the upper and lower wastewater channels to shorten the treatment route and treatment time, and the overall system It is possible to exhibit high throughput while minimizing the size of the device, and in addition, small carriers are taken out from the fluidized bed of small carriers formed in each of the descending and upward flow sections, regenerated, and then supplied again. Therefore, the contact area between microorganisms and wastewater can be kept constant, making it possible to continue treating wastewater with a constant efficiency.

Next, embodiments of the present invention will be described in detail based on the drawings.

A vertically long inner cylinder 2 equipped with a supply pipe 1 for wastewater to be treated is housed in a vertically long outer cylinder 4 equipped with a clean treated water takeout pipe 3, and a supersaturated tank 2 is installed at the upper part of the inner cylinder 2 at a pressure higher than atmospheric pressure. A device 5 for jetting and supplying oxygen-containing gas downward is connected to form a flowing portion A in the inner cylinder 2 in which the wastewater is lowered by the energy supplied from the wastewater and the gas. Oxygen in the gas is dissolved in the waste water by pressure, and the dissolved gas is bubbled in the outer cylinder 4 to create a wake of the waste water, thereby forming an upwardly flowing part B of the waste water in the outer cylinder 4, Wastewater flowing downwards part A
The wastewater is circulated and supplied by overflow, thereby forming a vertically deep circulating wastewater channel spanning the downward flow section A and the upward flow section B.

Each descending and ascending flow section A of this wastewater flow path.

A fluidized bed of small carriers A with microorganisms for aerobic wastewater treatment attached to the surface is formed in the deep part of B where the dissolved oxygen concentration is high, creating a watershed with a large amount of dissolved oxygen for microbial activity. In this process, wastewater is brought into contact with microorganisms with a surface area per unit volume, and the microorganisms adhere to and proliferate on the surface of a small carrier using organic components in the wastewater as nutrients, removing organic carbon from the wastewater and producing biochemical oxygen. The amount of water required is reduced and the resulting clean water is discharged from the outlet pipe 3.

The fluidized bed of the small carriers a in the downward flow section A is a downward flow of the small carriers a, which have microorganisms attached to their surfaces and whose apparent specific gravity is smaller than that of the wastewater. Part A
The increase in the microbial layer that accompanies wastewater treatment causes
As the descending action due to the increase in the pressure-receiving surface against the downward flow gradually increases, the small carriers a... are formed to descend one after another, and the small carriers a... in the upward flow portion B.
On the contrary, the fluidized bed of ... appears to be a small carrier a with a specific gravity.
... is supplied to the upward flow section B, and the upward force due to the increase in the pressure-receiving surface against the upward flow becomes larger than the downward force due to the increase in weight due to microbial growth, whereby the small carrier a ... should rise (form) sequentially.

In this wastewater treatment, if the layer of microorganisms attached to the small carrier a becomes thick, the contact area between the microorganisms and the wastewater per unit volume will decrease, and the treatment efficiency will decrease. In order to solve this problem, a small carrier regenerating device 6.7 is provided.

Small carrier a in the fluidized bed in the descending flow part A...
The regenerating device 6 connects the take-out pipe 8 for the small carriers a/ with the thick microbial layer to the downstream side of the flow path below the limit line where the adhered microbial layer becomes thick and the treatment efficiency decreases. At the same time, a detection mechanism 9 such as a phototube relay for detecting that the small carriers a/, . . . exceeds the limit line is provided in the inner cylinder 2, and the detection mechanism 9
a pump P that operates based on the detection result of , a device 10 for peeling off the adhering microorganism layer of the taken out small carriers a', and the small carriers having wastewater treatment microorganisms attached to their surfaces. A specific gravity sorting device 11 for sorting out a... and detached microorganisms is connected.

In addition, in this specific gravity sorting device 11, the small carriers a from which the attached microorganisms have been peeled off appear to have a smaller specific gravity than the wastewater, so they are floated and separated on the wastewater 4 surface regardless of the particle size. At the same time, the detached microorganisms are precipitated and subjected to gravity selection.

Then, the regenerated little finger body a.
. . . is configured to be supplied to the downward flow section A.

The small carrier regenerating device 7 in the other upward flow section B has a take-out pipe 12 for small carriers a', which have a thick microbial layer on the downstream side of the flow path from the limit line where the processing efficiency decreases. At the same time, a mechanism 13 for detecting that the small carrier a'... has exceeded the limit line is provided in the outer cylinder 4, and the detection result of the detection mechanism 13 is connected to the small carrier take-out flow path. Pump P1 and attached microorganism removal device 14 that operate based on
, and a specific gravity sorting device 15 for sorting and separating small carriers a... and microorganisms, and the regenerated small carriers a...
... should be supplied to the upward flow section B.

Then, the specific gravity sorting device j5se separates the detached microorganisms from the small carriers which have an apparent specific gravity compared to the microorganisms and waste water.

In addition, 16 in the figure is a device that separates the treated water from the specific gravity sorting device 15 into exfoliated and reduced organisms and clean water, and this device 1
The separated microorganisms from 6 and the specific gravity sorting device 11 are supplied to a treatment device 17 such as incineration, and clean water is supplied to the take-out pipe 3.

Further, 18 is a distributor provided on the upper side of the flow path of the small carrier fluidized bed, and is provided to uniformly flow the waste water.

19... is a magnetic net stretched to surround the small carrier fluidized bed, and the wastewater circulation flow rate can be set to high while preventing the small carriers from escaping from the fluidized bed. It is provided.

The oxygen gas supply device is provided only on the upstream side of the small carrier fluidized bed in the upwardly flowing section B, and the small carriers a for forming the fluidized bed in the downwardly flowing section A are supplied with anaerobic gas. If a microorganism for treating wastewater is attached, nitrogen content in the wastewater can be removed at the same time.

[Brief explanation of drawings]

The drawing is a flow sheet showing an embodiment of the wastewater treatment apparatus according to the present invention. a...Small carrier, A...Downward flow part,
B.......Upward flow part.

Claims (1)

[Claims] 1 Small carrier a with wastewater treatment microorganisms attached to its surface...
A fluidized bed of... is formed in both of the treated wastewater channels, which are formed from a deep downward flow section A and an upward flow section B connected below it, and in each of the two fluidized beds, The small carriers a are regenerated by the attached microorganism removal device 10.14 and the specific gravity sorting device 11.15, which are connected by the take-out pipe 8.12 of the small carriers a.
- A wastewater treatment apparatus which is equipped with regenerators 6 and 7 which are supplied to each of the fluidized beds.