No.10 ewater+ electrolyzed antibacterial water  Keeps the Toilet Bowl Clean Longer

Since its launch 30 years ago, the cumulative shipments of Washlet products have reached 30 million. Washlet products have been installed in homes, public facilities and transport systems, and now they are finding increased applications overseas. We have constantly innovated Washlet products by developing new functions to achieve greater comfort and cleanliness. This GREEN STORY looks into the development of ewater+ sanitizing water.

Satoru Matsumoto

Intelligent Materials Development Section, Washlet Development Department No. 1

Matsumoto worked on the development of ewater+ sanitizing water.

Koichiro Hiwa

Sanitary Valve Development Department, Faucets & Appliances Division

Hiwa worked on the development of ewater+ and the water-saving nozzle.

Chapter 1

We Analyzed Tap Water Taken at Over 200 Locations to Develop ewater+ By Satoru Matsumoto

Could we improve hygiene in the Washlet's nozzle? - This question led us to develop ewater+ sanitizing water. Although the nozzle in the conventional Washlet was already equipped with a function that performed before-and-after self-cleaning using tap water, we thought that using antibacterial water might improve hygiene more effectively. We thus decided to develop a system to clean the nozzle with innovative sanitizing water. Technology to generate slightly acidic hypochlorous acid water that has a sanitizing effect by electrolyzing minerals in tap water had already been developed, but there was no data on the sanitizing efficacy of electrolyzed tap water taken at different places.

So we analyzed tap water samples taken at more than 200 locations in Japan, and found that tap water that is "too clean" has too few minerals to achieve the necessary density of hypochlorous acid by electrolyzing. In fact, electrolyzed mineral-rich tap water creates clogging in the sanitizing water channel.

We then placed prototypes in areas where the mineral-rich water caused serious problems, and remotely monitored operations. When a clogging case was reported, we brought the prototype back and examined it before replacing it at the site. We repeated this process again and again, even in overseas locations, and eventually confirmed that the device operated effectively in Beijing, a city famous for its hard water. Naturally, it was far from easy to confirm the safety and durability as thoroughly as we did. But we made sure that we caused no trouble whatsoever for our customers.

Needless to say, our sanitizing water is environmentally friendly, as it reverts to being normal water after use. We launched it as "ewater+" into the global market this year. We would be delighted if our customers around the world could use it.

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Chapter 2

I made extra effort to completely satisfy customers, whether they prefer a "soft" or "hard" wash. By Koichiro Hiwa

ewater+ has a stain-resistant effect on the toilet bowl. Our analysis found that stubborn stains are caused by chemically altered bacteria. Fewer cleanings save water and use less detergent, and this means that to use ewater+ is environmentally friendly. More importantly, ewater+ makes it possible for us to use the toilet more comfortably. With this in mind, we examined how and where to use the sanitizing water most efficiently. First, we researched which part of the toilet bowl should be exposed to the sanitizing water. The system to generate the sanitizing water is so small that the amount of water generated each time is limited. So we devised a spraying device that uses less water. Then, we studied the best angle to spray the water. To fit the device to various shapes of toilet bowl, we took photographs of spatter patterns in different toilet bowls around the world. Based on the research results, we completed our "automatic-clean system," but we had to make an extra effort to install it in the Washlet. Our efforts were rewarded, as the toilet will stay hygienic for three months without cleaning.* My family has been participating in trials to monitor the usability, and the toilet bowl has definitely stayed clean for a long time.

For additional environmentally friendly functions, we struggled to develop a water-saving nozzle. TOTO is famous for our Wonder Wave rear-cleansing system, which pumps water as a series of fine beads, a technology that gives the user a comfortable wash using a small amount of water. By pumping out 100 water beads per second, both harder and softer, it uses only about half the amount of water used by conventional models. We focused on achieving comfort levels for users that defy measurement in numerical terms. I myself prefer a softer wash, so I asked my colleagues with stronger butts (Laughs), who prefer a hard stream, to participate in the usability trials repeatedly, until we could develop a water-saving nozzle that uses less water but doesn't feel like it. In our company, it is natural to make products that are environmentally friendly as well as comfortable. I think this attitude has driven us to keep innovating our Washlet line for more than 30 years.

* ewater+ suppresses the aggregation of stubborn stains, but this does not mean that the toilet does not have to be cleaned. The stain-resisting efficiency depends on the conditions in which it is used, such as water quality and the shape of the toilet bowl.

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