◾ What is Ultra Fine Bubble (UFB)?

• Fine bubbles are significantly smaller than the bubbles commonly observed in daily life. Specifically, bubbles with a diameter of less than 0.1 mm (100 μm) are categorized as fine bubbles.
• Fine bubbles are further classified into microbubbles, which measure between 1 and 100 μm in diameter, and ultrafine bubbles (UFB), which are 1 μm or smaller.
• Microbubbles are visible to the naked eye, appearing as cloudy white water, whereas ultrafine bubbles are too small to be seen without specialized equipment.
• To visualize the size difference, consider a baseball field where the distance from the batter’s box to the outfield fence represents 1 mm. In this analogy, an ultrafine bubble would be as small as a grain of sand on the field. (Based on research from AIST)

◾ Overview of Ultra Fine Bubble Technology

• Ultrafine bubble technology, an innovative advancement originating in Japan, is poised to serve as a cornerstone for the future development of key industries in our country.
• This technology, which produces ultrafine bubbles by mixing gas and liquid, is already being applied across a wide range of fields, including cleaning, sterilization, water purification, and the handling of materials in liquids. Its uses span sectors such as mining, agriculture, forestry, fisheries, and infrastructure.

◾ About Ultra Fine Bubble Generator

• The Ultra Fine Bubble (UFB) generator is a device specifically designed to cool and clean the blades of industrial cutting machines by circulating water.
• A key feature of the UFB generator is its mechanical dirt removal and cleaning capability. It was developed to ensure stable mold cooling by eliminating dirt from cooling tanks and chiller tubes, preventing water corrosion, and addressing clogs in the tubes through effective cleaning. Additionally, by purifying the water, the generator improves the working environment, reduces the frequency of water replacement, saves water, and lowers labor costs by shortening cleaning times.
• Intense agitation and mixing of liquids create turbulence, which results in the generation of ultrafine bubbles. This process also leverages the "Coanda effect," where liquids exhibit clinging and sticking behaviors.
• To optimize the performance of the processing fluid, the equipment utilizes "flip-flop flow." This phenomenon occurs when water flows through a square tube with diamond-shaped columns arranged in a mesh-like pattern. The vortices generated within the tube cause the liquid jet to oscillate regularly from side to side, enhancing mixing and efficiency.
• The device’s intricate internal structure represents the culmination of advanced fluid dynamics theory, embodying cutting-edge technological innovation.
• The UFB water generator operates effectively at a water pressure of 1 Kgf or higher. Since typical tap water pressure ranges from 2 to 4 Kgf, the device is compatible with ordinary tap water, making it practical and versatile for a variety of applications.

We have successfully developed a method to generate ultrafine bubbles (UFB) using a single component instead of bulky equipment. This innovation has been applied to create the UFB shower head for home use, as introduced here.

• Many UFB generators from other companies rely on water, air, and pressure pumps to produce UFB, resulting in equipment that is large, expensive, and space-consuming.
• In contrast, our UFB generator is compact and space-efficient, as it generates UFB by simply utilizing water pressure to twist oxygen into the water.
• Key features of our device include its power-free operation and the ability to customize its size to suit various applications.
• Unlike systems that use activated charcoal or tourmaline stones, our generator requires no replacement of internal components, enabling semi-permanent use as long as the main unit remains intact.
• The UFB showerhead produces nano-sized bubbles of exceptional size, delivering the remarkable benefits of UFB technology in an easily noticeable way.

※ Data measured using the Nano Site System by Quantum Design Japan, an independent research organization, revealed the presence of 60 to 70 million ultrafine bubbles (UFB) per cubic centimeter.

　The UFB showerhead delivers an exceptional cleaning effect without the need for shampoos, soaps, or body washes. Ultrafine bubbles penetrate even the tiniest pores, effectively adsorbing and removing dirt. This high cleaning power has been proven to be gentle and safe, making it suitable for everyone, including individuals with sensitive skin or concerns about sebum and dirt.

② Odorless and Fresh

　Even if you wash your hair without solvent, you will find that the hair is very fluffy and odorless after washing. The cleansing and washing effects can be experienced and maintained, as well as preventing diseases caused by dirt adhering to the skin.

③ Reduced Cleaning Time

　With no solvents required, the cleaning process is significantly quicker, leading to shorter bath times and greater convenience.

④ Easy Installation

　The UFB showerhead is designed for easy replacement and can be installed in any standard home bathroom without the need for additional setup or professional installation.

⑤ Cost-Effective

　Unlike products that rely on activated charcoal or tourmaline stones, this showerhead requires no replacement parts and can be used semi-permanently as long as the unit remains intact. Priced under 20,000 yen, it offers an affordable and accessible solution for households. 

　By using the shower on a bathroom mirror daily, you can observe the gradual removal of water stains, leaving the mirror increasingly clean and shiny. Additionally, the UFB showerhead effectively removes dirt and grime, offering a noticeable cleaning effect that can help improve or even resolve plumbing issues.

◾ Improvement of stains after installation in plumbing for toilet flushing

※ Four months after installation in the plumbing for toilet flushing, the yellowing and blackening of the toilet bowl was removed and improved.

3． Example of Ultra Fine Bubble (UFB) Generator

West Nippon Expressway Company Limited (NEXCO West Japan) 

◾ Efforts to Advance Highway Maintenance Management Using Ultra Fine Bubbles

 West Nippon Expressway Co., Ltd. is utilizing new technologies to enhance expressway maintenance and management and to improve service quality (CS).

◾ Ultra Fine Bubble Water for Toilet Cleaning Initiatives

We view restrooms at rest facilities as an important point of contact with users, and since privatization, we have been focusing on drastic improvement of the restroom environment. As part of these efforts, a new restroom cleaning method using ultra fine bubble water ("UFB water") was launched at rest facilities in the Chugoku region in FY2010, and is being gradually expanded to rest facilities throughout western Japan.

Effect

This cleaning method consists of spraying UFB water on the toilet floor with a sprayer and wiping it off with a mop, with the following effects.

Effect ① Significant reduction in overall work time

Compared to conventional washing in water with detergent, the work time is reduced by 30% with light equipment.　　

Effect ② Significant reduction in water consumption

The amount of water used is significantly reduced, and the amount of detergent used is small, thus reducing the environmental impact to 1/100th of the previous level. 　　  

Effect ③ Reduced floor drying time

Floor drying time is reduced by 40%, and customers' feet do not slip.

◾ West Nippon Expressway Company Limited (NEXCO West Japan)

• In the beginning, UFB generators (BUVITAS) were placed at transportation bases and transported to each rest facility by truck, etc. In 2014, Ligaric Co., Ltd. successfully developed a compact UFB generator (BUVITT), and we are now working to install it at all rest facilities in our jurisdiction under a five-year plan starting in 2015.
• Based on the above, the UFB cleaning implementation rate for application to rest facilities is now approximately 90% within NEXCO West's service area.

Conventional cleaning methods

◾ Bridge Girder Cleaning Initiatives

（1）Objective

Efficient maintenance, repair, and renewal of structures is an important issue for extending the service life
of structures, and it is imperative to do so efficiently within a limited budget.　In particular, the aging of
bridges is a problem not only because of damage to bridges caused by larger vehicles and overloading,
but also because of accelerated deterioration due to the adhesion of salt to bridge girders from bridge
joints caused by flying salt on routes passing near the coast and the application of anti-freeze (sodium
chloride) to secure road surfaces during the winter. This has become a problem. Therefore, from the
viewpoint of preventive maintenance, salt is removed by washing bridge girders.

（2）Ultra Fine Bubble Water Cleaning　 

In bridge girder washing, it has been confirmed that UFB water can remove salt relatively quickly
compared to ordinary water, improving work efficiency. For this reason, we have begun using UFB water

for bridge girder cleaning.

【 Residual salinity diagram 】

◾ Initiatives to Reduce Sludge Volume at Rest Facilities

（1） Purpose of Technology Development

Approximately 40% of the 303 rest facilities in NEXCO West Japan's service area use septic tanks for

treatment. The cost of sludge disposal is increasing every year, and reducing this cost is an urgent issue,

along with reducing road maintenance costs, which will increase in the future. In order to solve this problem, we have been conducting research and development on the application of ozone gas (O3) ultrafine bubble (O3UFB) technology to septic tanks in collaboration with Hiroshima University (Prof. Nishijima) since FY 2013.

（2） Sludge Volume Reduction Mechanism

A. Shear and refine sludge floc

Excess sludge is sucked into the UFB generator and shear stress is applied to the sludge floc together with gas, causing it to become finer.

B. O3UFB penetrates inside the miniaturized sludge floc

The ultrafine bubbles of O3UFB easily penetrate into the sludge floc and accelerate the reaction inside the floc.

◾ Research Status

• Currently, an experimental plant has been installed at the Okuya parking area (PA) on the Sanyo Expressway to establish a sludge volume reduction technology using O3UFB. 
• As of August 2016, the volume reduction rate of 70% was achieved, and the tanks were removed by the end of the fiscal year. Based on the results of this study, we are considering applying the results to septic tanks in rest facilities that will be newly built or reconstructed in the future.

【 Okuya PA Demonstration Experiment Status 】