JPH07303895A - Water treatment apparatus - Google Patents

Abstract

PURPOSE:To provide a water treatment apparatus having simple constitution capable of performing the biological treatment and solid-liquid separation of water to be treated. CONSTITUTION:To a submerged reaction tank 1 having descending and ascending passages 2, 3 allowing water to be treated to circulate and flow formed thereto and provided with an aeration means such as an ejector 9 supplying aeration air to the water to be treated falling through the descending passage 2, the immersion type membrane separator 10 positioned in the ascending passage 3 and subjecting the water to be treated to solid-liquid separation is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment apparatus for biological treatment of water to be treated such as organic wastewater and solid-liquid separation.

[0002]

2. Description of the Related Art Conventionally, as a device for biological treatment of water to be treated such as organic wastewater, a relatively deep downward flow path and upward flow path are formed, and the downward flow path and the upward flow path are formed. There is known a deep reaction tank provided with a circulation means for circulating and flowing the water to be treated and an aeration means for supplying aeration air to the water to be treated which descends in the downward flow path. In such a deep-layer reaction tank, the aeration air is blown in such a manner that the water to be treated is introduced into the tank and circulated and flowed by the circulation means while the DO in the tank is in a condition suitable for nitrification / denitrification. In the above, the treated water is biologically nitrified and denitrified by the activated sludge in the tank. Then, in order to separate the activated sludge from the mixed liquid in the tank thus nitrified and denitrified, solid-liquid separation is performed by an immersion type membrane separation device or the like.

[0003]

However, when solid-liquid separation is carried out by the above-mentioned immersion type membrane separation apparatus, it is a conventional technique to install a membrane raw water tank for the membrane separation apparatus, and therefore, the apparatus and treatment are performed. Is complicated.

The present invention solves the above problems, and an object of the present invention is to provide a water treatment apparatus having a simple structure capable of performing biological treatment and solid-liquid separation of treated water.

[0005]

In order to solve the above problems, the water treatment apparatus of the present invention forms a downward flow passage and an upward flow passage for circulating the water to be treated, and the downward flow passage is formed. A deep-layer reaction tank equipped with aeration means for supplying aeration air to the water to be treated that descends inside is provided with an immersion type membrane separation device located in the upward flow path for solid-liquid separation of the water to be treated in the tank. It is a thing.

[0006]

With the above structure, biological treatment and solid-liquid separation of the water to be treated can be performed in a state of circulating and flowing in the deep reaction tank. At this time, since aeration air is supplied from the aeration means to the water to be treated descending in the downward flow path,
The aerated air is entrained in the water to be treated and descends in the downward flow path, and then rises in the upward flow path, and the oxygen in the descending aerated air is sufficiently dissolved in the water to be treated and rises. The surface of the separation membrane of the immersion type membrane separation device is washed by the bubbles of the aerated air.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall structure of a water treatment apparatus according to an embodiment of the present invention, in which a deep-layer reaction tank 1 is composed of a downward flow path 2 and an upward flow path 3. A pump tank 5 is provided on the outer peripheral side of the upward flow path 3 via an overflow weir 4, and the water to be treated is supplied to the pump tank 5 from a treated water supply pipe 6 and is directed upward. The water to be treated in the flow path 3 overflows from the overflow weir 4.

The pump tank 5 is communicated with the top of the downward flow path 2 through a circulation pipe 8 equipped with a stirring means such as a stirring pump 7, whereby the water to be treated in the pump tank 5 is stirred. The pump 7 pumps water to the top of the downward flow passage 2, and circulates and flows in the circulation passage extending from the downward flow passage 2 and the upward flow passage 3 to the pump tank 5. At the top of the downward flow passage 2, an aeration means such as an ejector 9 for supplying aerated air to the water to be treated that descends in the downward flow passage 2 is provided.

An immersion type membrane separation device 10 for solid-liquid separating the water to be treated in the tank is provided in the upper part of the upward flow path 3. The submerged membrane separation apparatus 10 is configured by connecting a plurality of membrane elements such as a tubular ceramic separation membrane or a flat plate-type separation membrane having a filtration membrane. The membrane separation device 10 is provided with a suction tube 12 that is connected to the permeate side and that is equipped with suction means such as a suction pump 11.

A secondary treated water tank 13 for storing permeated water taken out by the submerged membrane separation apparatus 10 is arranged outside the deep reaction tank 1, and a transfer pump 14 is provided in the secondary treated water tank 13. Has been.

The operation of the above structure will be described below.
When the agitating pump 7, the ejector 9, and the suction pump 11 are driven, when the treated water is introduced from the treated water supply pipe 6 into the pump tank 5, the treated water flows from the pump tank 5 to the top of the downward flow path 2. The water is pumped up to the inside of the downward flow path 2, then descends in the upward flow path 3, and then rises in the upward flow path 3 to flow into the pump tank 5 from the overflow weir 4, together with the water to be treated in the deep reaction tank. Circulate and flow.

At this time, aeration air serving as DO suitable for nitrification and denitrification is supplied from the ejector 9 to the circulating water to be treated water at the top of the downward flow path 2. It is sufficiently dissolved in the water to be treated due to the stirring and the water depth when descending in the counter flow passage 2.

The water to be treated is biologically nitrified and denitrified by the activated sludge in the tank in the state where the aerated air is supplied while being circulated and flown in this manner, and the solid water is liquefied by the membrane separation device 10. The permeated water that has been separated and has passed through the separation membrane of the membrane separation device 10 is sent to the secondary treatment water tank 13 through the suction pipe 12. In the membrane separation device 10, the surface of the separation membrane is washed by a circulating flow of water to be treated or a bubble flow of aerated air,
Accumulation of deposits is prevented.

[0014]

As described above, according to the present invention, the immersion type membrane separation device is provided inside the deep-layer reaction tank in which the aerated air is effectively supplied while circulating the water to be treated. The biological treatment and solid-liquid separation of the water to be treated can be suitably performed in a single tank.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a water treatment device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Deep reaction tank 2 Downward flow path 3 Upward flow path 9 Ejector (aeration means) 10 Immersion type membrane separation device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 9/00 503 C 504 A

Claims (1)

[Claims] 1. A deep-layer reaction which forms an downward flow path and an upward flow path for circulating the water to be treated and which is provided with aeration means for supplying aeration air to the water to be treated descending in the downward flow passage. A water treatment device, characterized in that the tank is provided with an immersion type membrane separation device which is located in the upward flow path and performs solid-liquid separation of the water to be treated in the tank.