Ultrafine bubble cleaning method using ultrafine bubble-containing liquid, apparatus therefor, and dissolved air floatation apparatus

Abstract

An ultrafine bubble cleaning apparatus uses a liquid containing ultrafine bubbles having a size of less than 30 nm to rinse fine particles adhered to soil, sand, etc. to separate and collect the fine particles. The ultrafine bubble cleaning apparatus includes a water tank-shaped reservoir, a stirring device, a supernatant discharge device including a pump for discharging a supernatant of the liquid in the reservoir, and a sedimentation extraction device. Substances are loaded into the ultrafine bubble-containing liquid stored in the reservoir, and the ultrafine bubble-containing liquid is repeatedly brought into contact with the surface of the substance using the stirring device. When ultrafine bubbles get into a space between fine metal particles adhered to the surfaces, cracks, and pits of the substances to be cleaned (including metal ions) and fine particles of organic substances including a solvent, a chemical, and oil, the fine particles are separated and floated.

1 . An ultrafine bubble cleaning method for cleaning a substance to be cleaned, comprising: swirling a liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm and bubbles larger than the ultrafine bubbles to concentrate a part thereof that contains the ultrafine bubbles and has a relatively large specific gravity outside a swirling flow, and concentrate a part thereof that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity to a central part of the swirling flow followed by discharge, storing the ultrafine bubble-containing liquid containing the ultrafine bubbles concentrated outside in a reservoir, such as a water tank and a pond, stirring the ultrafine bubble-containing liquid in a state in which the substance to be cleaned, such as soil, sand, stone, fallen leaves, rubble, boards, and sheets, is contained, washing off fine particles adhered to the substance to be cleaned while causing the fine particles to be adsorbed on an interface of the ultrafine bubbles, causing the fine particles to be floated as a floated and separated substance, and causing the substance to be cleaned in which the fine particles are rinsed off to be settled as sedimentation isolates; and discharging a supernatant containing the floated and separated substance. 
     
     
         2 . The ultrafine bubble cleaning method according to  claim 1 , wherein
 the reservoir includes first and second small reservoirs that are a plurality of water tanks, ponds, and marshes or a single pond or marsh that is partitioned, and   a step of continuously loading the substance to be cleaned to the first small reservoir, transporting a sediment at a bottom, and loading the sediment into the second small reservoir and a step of pouring the ultrafine bubble-containing liquid into the second small reservoir and sending a supernatant of the second small reservoir to the first small reservoir are repeated to rinse, at the second small reservoir, the substance that has been cleaned at the first small reservoir.   
     
     
         3 . (canceled) 
     
     
         4 . An ultrafine bubble cleaning method comprising: swirling water containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm and bubbles larger than the ultrafine bubbles to concentrate a part thereof that contains the ultrafine bubbles and has a relatively large specific gravity outside a swirling flow, and concentrate a part thereof that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity to a central part of the swirling flow followed by discharge; and mixing and stirring the ultrafine bubble-containing water containing the ultrafine bubbles that is concentrated outside in raw water in which fine droplets of an organic substance, such as oil and insulating oil, are dispersed to attach the ultrafine bubbles to the fine droplets and cause the fine droplets to be floated and separated due to buoyancy of the ultrafine bubbles. 
     
     
         5 . An ultrafine bubble cleaning apparatus comprising:
 an ultrafine bubble-containing liquid production device swirling a liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm and bubbles larger than the ultrafine bubbles to concentrate a part thereof that contains the ultrafine bubbles and has a relatively large specific gravity outside a swirling flow, and concentrate a part thereof that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity to a central part of the swirling flow followed by discharge.   
     
     
         6 . The ultrafine bubble cleaning apparatus according to  claim 5 , wherein
 the reservoir includes a first small reservoir and a second small reservoir,   the first small reservoir is provided with a first stirring device, a first supernatant discharging device, and a first sedimentation extraction device,   the second small reservoir is provided with a second stirring device, a second supernatant discharging device, and a second sedimentation extraction device,   the first sedimentation extraction device is configured to continuously load the sediment that is continuously extracted from the first small reservoir and cleaned into the second small reservoir,   the second supernatant discharging device is configured to continuously supply the supernatant in the second small reservoir as cleaning water to the first small reservoir,   the first supernatant discharging device is configured to discharge the supernatant of the first small reservoir as a waste liquid after cleaning, and   the second sedimentation extraction device is configured to discharge the sediment in the second small reservoir as a rinsed substance to be cleaned.   
     
     
         7 . The ultrafine bubble cleaning apparatus according to  claim 5 , wherein the stirring device is configured to stir a liquid provided from the ultrafine bubble-containing liquid production device in the reservoir by newly jetting the ultrafine bubble-containing liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm to the reservoir. 
     
     
         8 . An ultrafine bubble cleaning apparatus comprising:
 an ultrafine bubble-containing liquid production device swirling a liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm and bubbles larger than the ultrafine bubbles to concentrate a part thereof that contains the ultrafine bubbles and has a relatively large specific gravity outside a swirling flow, and concentrate a part thereof that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity to a central part of the swirling flow followed by discharge; a reservoir configured to be capable of containing raw water in which fine droplets of an organic substance, such as oil and insulating oil, are dispersed; an ultrafine bubble-containing water supply device configured to supply an ultrafine bubble-containing water produced by the ultrafine bubble-containing water production device to raw water of the reservoir; a stirring device that is provided in the reservoir and configured to stir the raw water stored thereinside; and a floated substance and liquid discharging device configured to discharge fine droplets that are adsorbed on an interface of ultrafine bubbles in the ultrafine bubble-containing liquid and floated by the stirring.   
     
     
         9 . (canceled) 
     
     
         10 . A dissolved air floatation apparatus comprising an ultrafine bubble-containing liquid production device swirling a liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm and bubbles larger than the ultrafine bubbles to concentrate a part thereof that contains the ultrafine bubbles and has a relatively large specific gravity outside a swirling flow, and concentrate a part thereof that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity to a central part of the swirling flow followed by discharge, and a dissolved air floatation tank provided with an inlet at one end, wherein a pressurized ultrafine bubble-containing liquid is mixed in a raw liquid and is poured into the dissolved air floatation tank from the inlet to cause a suspended substance and a dissolved component in the raw liquid to be adsorbed on an interface of fine bubbles and be floated in the dissolved air floatation tank, and the suspended substance and the dissolved component are extracted as a suspended and separated substance from the raw liquid, and a remaining raw liquid is discharged as a treated liquid, the dissolved air floatation apparatus comprising:
 a circulating device configured to circulate a mixed liquid of the raw liquid and the ultrafine bubble-containing liquid in the dissolved air floatation tank; and 
 a floated and separated substance collecting device configured to extract a floated and separated substance that is floated to a liquid surface by ultrafine bubbles contained in the ultrafine bubble-containing liquid in the dissolved air floatation tank. 
 
     
     
         11 . The dissolved air floatation apparatus according to  claim 10 , wherein the circulating device includes
 a swirling discharge pipe that is provided at a lower portion of the dissolved air floatation tank so as to be projected therefrom and jets the mixed liquid of the raw liquid and the ultrafine bubble-containing liquid as a swirling discharge flow to the dissolved air floatation tank,   a swirling flow guide that has a cylindrical shape having an opening at upper and lower ends thereof and causes the swirling discharge flow to flow diagonally upward, and   a gap provided between the lower end opening of the swirling flow guide and a bottom of the dissolved air floatation tank.   
     
     
         12 . The dissolved air floatation apparatus according to  claim 10 , comprising a flocculant reaction tank device that is provided on an entry side of the raw liquid into the dissolved air floatation tank, and in which at least one of an organic flocculant, an inorganic flocculant, and a radioactive substance adsorbent is mixed as a flocculant in the raw liquid before mixing the raw liquid and the ultrafine bubble-containing liquid. 
     
     
         13 . (canceled) 
     
     
         14 . The ultrafine bubble cleaning method according to  claim 1 , wherein the liquid containing the ultrafine bubbles and bubbles larger than the ultrafine bubbles is swirled in a storage type pressurized liquid tank in a full state all the time. 
     
     
         15 . The ultrafine bubble cleaning apparatus according to  claim 8 , wherein the ultrafine bubble-containing water production device has a storage type pressurized liquid tank configured to swirl the water containing the ultrafine bubbles and the bubbles larger than the ultrafine bubbles in a full state all the time, the storage type pressurized liquid tank including a central liquid discharge port for discharging a part that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity from above by swirling the water in an inside thereof, and a pressurized liquid discharge port provided at a lower side face. 
     
     
         16 . The dissolved air floatation apparatus according to  claim 10 , wherein the ultrafine bubble-containing water production device has a storage type pressurized liquid tank configured to swirl the liquid containing the ultrafine bubbles and the bubbles larger than the ultrafine bubbles in a full state all the time, the storage type pressurized liquid tank including a central liquid discharge port for discharging a part that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity from above by swirling the water in an inside thereof, and a pressurized liquid discharge port provided at a lower side face. 
     
     
         17 . The ultrafine bubble cleaning apparatus according to  claim 6 , wherein the stirring device is configured to stir a liquid provided from the ultrafine bubble-containing liquid production device in the reservoir by newly jetting the ultrafine bubble-containing liquid containing ultrafine bubbles having a size of 3 Å or more and less than 30 nm to the reservoir. 
     
     
         18 . The dissolved air floatation apparatus according to  claim 11 , comprising a flocculant reaction tank device that is provided on an entry side of the raw liquid into the dissolved air floatation tank, and in which at least one of an organic flocculant, an inorganic flocculant, and a radioactive substance adsorbent is mixed as a flocculant in the raw liquid before mixing the raw liquid and the ultrafine bubble-containing liquid. 
     
     
         19 . The ultrafine bubble cleaning method according to  claim 2 , wherein the liquid containing the ultrafine bubbles and bubbles larger than the ultrafine bubbles is swirled in a storage type pressurized liquid tank in a full state all the time. 
     
     
         20 . The dissolved air floatation apparatus according to  claim 11 , wherein the ultrafine bubble-containing water production device has a storage type pressurized liquid tank configured to swirl the liquid containing the ultrafine bubbles and the bubbles larger than the ultrafine bubbles in a full state all the time, the storage type pressurized liquid tank including a central liquid discharge port for discharging a part that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity from above by swirling the water in an inside thereof, and a pressurized liquid discharge port provided at a lower side face. 
     
     
         21 . The dissolved air floatation apparatus according to  claim 12 , wherein the ultrafine bubble-containing water production device has a storage type pressurized liquid tank configured to swirl the liquid containing the ultrafine bubbles and the bubbles larger than the ultrafine bubbles in a full state all the time, the storage type pressurized liquid tank including a central liquid discharge port for discharging a part that contains bubbles larger than the ultrafine bubbles and has a relatively small specific gravity from above by swirling the water in an inside thereof, and a pressurized liquid discharge port provided at a lower side face. 
     
     
         22 . (canceled)