JP2003154357A - Method for purifying wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely purify wastewater by a simple means in which hydrophobic ultra-fine bubbles A (several microns in diameter) are charged into the wastewater to separate/remove fine particles 5 by recovering the particles 5 floated by being adsorbed by the bubbles A. SOLUTION: In a method for purifying wastewater containing the hydrophobic fine particles 5, the ultra-fine bubbles A are charged into the wastewater, the fine particles 5 are adsorbed by the bubbles A to be floated, and the particles 5 in the wastewater are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater purification method for separating and removing fine particle substances (floating substances) from wastewater to purify the wastewater.

[0002]

Conventionally, in waste water containing a suspended substance (suspended substance SS) having a particle diameter of 2 mm or less that is not soluble in water, a method for separating and removing fine particle substances in the waste water is coagulation. Separation methods such as precipitating fine particles by adding agents or collecting and lifting fine particles by a pressure floating method are used, but when a flocculant is used, running costs increase due to the use of agents, and There are inconveniences such as an increase in sludge generated after aggregation. Further, the pressure floating method has a disadvantage that a pressure device such as a pressure pump is required separately.

[0003]

Therefore, the present invention provides a method for purifying wastewater having a hydrophobic fine particle substance, in which ultrafine bubbles are introduced into the wastewater so that the fine particles are adsorbed by the bubbles and floated. It removes the fine particles of the above, and it collects the fine particles that are adsorbed by the ultra-fine bubbles (about several μm) and floats up, separates and removes the fine particles, and just puts the ultra-fine bubbles into the waste water. This makes it possible to purify wastewater with good accuracy by simple means.

Also, by generating ultrafine bubbles from ozone gas, it is possible to purify wastewater with high accuracy by introducing ultrafine bubbles made of ozone gas, and at the same time, chromaticity and odor due to the decomposition and removal of organic substances of ozone. Is also removed satisfactorily to enable more advanced purification of wastewater.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view of a wastewater purification system, and FIG. 2 is a cross-sectional explanatory view of a wastewater purification tank. A wastewater storage tank 1 for storing wastewater from a home or a factory, a storage drainage of the storage tank 1 and a water pipe 2 A waste water purification tank 4 that flows in through the water supply pump 3, and a recovery tank that collects and stores 5 minutes of fine particulate matter, which is the suspended solid SS generated in the purification tank 4, through a recovery device 8 such as the drain pipe 6 and the discharge pump 7. 9 and a discharge valve 10 that discharges the purified water in the purification tank 4, and the purification tank 4 has a circulation pump 11.
The air supply passage 14 for introducing the air from 3 and the drainage and the air from the supply unit 13 are mixed to crush the bubbles in the drainage into ultrafine particles (about several μm) to supply the ultrafine bubbles A to the cleaning tank 4. The gas-liquid mixing type line mixer 15 is provided.

While the ultrafine air bubbles A from the line mixer 15 are being supplied to the purification tank 4 and are rising, the fine particles 5 having hydrophobicity in the waste water are discharged into the air bubbles A.
It is adsorbed on the surface of the tank 4 and floats to form an aggregate layer 16 of the fine particulate matter 5 on the upper surface of the drainage of the tank 4. The aggregate layer 16 is recovered by driving the discharge pump 7 to separate and remove the fine particulate matter 5 in the wastewater. To purify the emissions.

In the above-described embodiment, the discharge pump 7 is used as the recovery unit 8 for the fine particle substance 5; however, a recovery device for scraping off or removing the fine particle substance 5 by scooping is used. It may be configured.

Further, in the above-mentioned embodiment, the structure in which the fine particles 5 are adsorbed by the air bubbles A by the air is shown, but as shown in FIG. 3, the ozone generator 17 is connected to the circulation passage 12 via the ozone supply passage 18. To generate ultra-fine bubbles B by ozone gas and supply them as ozone gas bubbles B into the wastewater. The ultrafine bubbles B adsorb and float 5 minutes of fine particles in the wastewater, and at the same time, decompose and remove organic matter of ozone. By removing the chromaticity and odor in the wastewater by such means, it is possible to easily purify the wastewater in which all the conditions such as composition, chromaticity and odor are optimized.

The air supply unit 13 and the ozone generator 17
Both of them are connected to the circulation flow path 12 via a switching valve or the like,
A configuration may be used in which either air or ozone gas is selected and used according to the component of the fine particle substance 5 and the like.

[0010]

As is apparent from the above examples, in the method for purifying wastewater having the hydrophobic fine particle substance 5, the ultrafine bubbles A are put into the wastewater so that the fine substance 5 is adsorbed by the bubbles A and floated. Since the fine particles 5 in the wastewater are removed, the fine particles 5 that are adsorbed by the ultrafine bubbles (about several μm) A and floated up are collected to reliably separate and remove the fine particles 5. It is possible to purify the wastewater with high accuracy by a simple means of only introducing the ultrafine bubbles A into the wastewater.

Further, since the ultra-fine bubbles B are generated by ozone gas, by introducing the ultra-fine bubbles B made of ozone gas, it becomes possible to purify the waste water with good accuracy, and at the same time, the action of decomposing and removing organic substances of ozone, etc. With this, chromaticity and odor can be removed satisfactorily, and more advanced purification of wastewater can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a wastewater purification system.

FIG. 2 is a cross-sectional explanatory view of a wastewater purification tank.

FIG. 3 is a cross-sectional explanatory view of a wastewater purification tank.

[Explanation of symbols] 5 Fine-grained substances (suspended substances) A / B Ultrafine air bubbles

Claims (2)

[Claims] 1. A method for purifying wastewater having a hydrophobic fine particle substance, characterized in that ultrafine air bubbles are introduced into the wastewater to adsorb the fine particle substance to the air bubbles so as to float and remove fine particle substances in the wastewater. How to purify wastewater. 2. The method for purifying wastewater according to claim 1, wherein ultrafine bubbles are generated by ozone gas.