Cleaning tech that makes people want to wash their hands

Interesting Engineering (IE) interviewed one of the study's scientists, Weston Baxton, from Imperial University, U.K., to explore how this innovation could potentially enhance the accessibility and popularity of hand cleansing worldwide.

Soap technologies in resource-poor societies

The study underscores the significant challenges of developing regular handwashing habits in rural and peri-urban Tanzania, due to limited ecological, economic, and technological resources.

"Our research confirmed high knowledge and awareness of handwashing even in remote areas. However, several barriers hindered actual handwashing practice," Baxter told IE. 

One major hurdle was that the available soap had to stretch to multiple uses, including bathing, laundry, and dishwashing, meaning it was often unavailable when needed for handwashing. Additionally, soap was often inconveniently located away from where it was needed, and was sometimes deemed unhygienic, from previous users handling it after using the toilet.

"The soap was also not often in a convenient location and was seen as disgusting since previous people often had used it after cleansing themselves post-defecation," Baxter added. 

A recent field study in a typical small Tanzanian town found that only 13 percent of households had access to a handwashing facility. Nationally, as of 2016, merely 7 percent of households in Tanzania had a fixed handwashing station equipped with soap and water.

While recent advances in building rural handwashing facilities, seen in projects like Kenya's 'Povu Poa' and Vietnam's 'Happy Tap,' emphasize collaboration with design professionals and iterative prototyping to create functional and appealing options, their scalability and sustainability remain unproven.

In their recent Tanzanian study, Baxter's team directly engaged with local residents to gather insights on existing hand-cleansing technologies.

The study stressed the need for user-friendly handwashing solutions that allow the easy washing of both hands, ideally with soap. The study found that options involving water refilling systems were often perceived as inconvenient.

Additionally, there were challenges in understanding how to use certain products. For instance, one respondent labeled a product called 'the Supertowel' as 'fake.' 

Such reactions highlighted the crucial role of clear communication and ensuring that washing technologies meet user expectations.

With these insights in mind, the researchers then aimed to develop and evaluate a post-defecation handwashing system that is not only effective but also attractive, practical, and sustainable. Their primary focus was on households lacking on-site water connections.

How does 'Tab Soap' work?

The paper highlighted how one set of unique selling propositions shaped the ultimate design of Tab Soap.

"For low-income residents who want to leave cholera behind and become modern, Sabom (Swahili for 'soap') is soap for handwashing that gives you a fresh piece of soap every time you use it, even in a shared context. This contrasts with the common bar of soap found in the toilet, which is seen as disgusting," wrote the researchers. 

While IE's interview with Baxter didn't provide specific details about the manufacturing process of Tab Soap, the study underscores that this process was designed with careful consideration of the tools and workforce available in Tanzania.

Because the final product is made up of tabs of soap integrated into a material substrate (e.g. a single-use washcloth), its usage results in some waste. 

To address this, the researchers opted for biodegradable material designed to decompose in the pit latrines prevalent in the environment. Specifically, the selected material was a bamboo-based textile capable of absorbing various soap types.

Throughout the study, the researchers placed a strong emphasis on the tab soap incorporating both behavior-centered design and human-centered design. When asked to explain this, Baxter provided a more straightforward breakdown.

He began by defining human-centered design as a process where you immerse yourself in a specific situation to truly understand the challenges from the perspective of the people who will use the solution. Then, you work alongside these people to create a solution that fits their needs.

Behavior-centered design is similar, but goes a step further. It incorporates theories about why and how people behave in specific ways. This approach aims to design solutions that not only work but also influence behavior positively.

"We used both processes to co-design Tab Soap by first understanding the challenge from the perspective of many stakeholders and then creating a theory-led solution that people were excited about," Baxter told IE. 

Encouraging handwashing

"Everyone could get access to soap and water, and all have been taught the importance and method of washing their hands," Baxter said.  "Our focus was redesigning soap itself to encourage handwashing with soap." 

"The soap incorporates several behavioral insights to create a meaningful interaction," he added, arguing that Tab Soap offers a novel experience through the use of biodegradable substrate infused with soap that foams up on use. 

Significantly, "The tab is made only for handwashing, so it clearly connotes the desired behavior and cannot be easily used for anything else."

Moreover, "it is seen as clean since it is single use as a barrier to existing soap usage that previous users have touched the soap after cleansing themselves [which is sometimes] seen as dirty."

Another advantage, he claims, is that Tap Soap is highly portable and robust. For instance, the user can place the soap in their pocket and bring it with them. 

The combination of these and other features has created a low-cost solution for handwashing with promising behavioral outcomes. 

Baxter explained that assessing private behaviors like handwashing can be tricky. That said, to measure the effectiveness of Tab Soap, the team used three methods.

First, they conducted a survey where people reported their handwashing habits. However, Baxter noted that this self-reported data can be unreliable, especially for behaviors people feel they "should" do.

Second, they placed electronic sensors in the soap dispensers to track usage. This allowed them to verify that people were using the device regularly rather than just before it was refilled.

Finally, they enlisted local soap sellers to refill the devices weekly and report how many remained. Combining this information with data on the total units provided and the number of people in households, they calculated the average daily usage rate per person.

"The research to date has offered strong support for Tab Soap being successful in promoting behavior change," emphasized Baxter.

"Next, we want to partner with organizations to trial the production, distribution, and repeated purchase of the product at a larger scale. When linked to a successful business model, Tab Soap could be a clear public health success with an associated sustainable financial model," he concluded. 

The future of soap

In a world where handwashing with soap is a powerful tool for reducing infectious diseases, it's surprising that this simple act is often overlooked, especially in areas where it can make the most difference.

The potential implications of Tab Soap are significant. As a low-cost, behavior-focused solution, it could revolutionize handwashing practices, particularly in resource-poor areas.

With further trials and a sustainable business model, Tab Soap may indeed become a global public health success story. However, it's too early to make a definitive judgment at this stage of its development.

Will it follow the path of Kenya's 'Povu Poa' and Vietnam's 'Happy Tap,' which have yet to achieve scale or sustainability? Or will it be the soap innovation that breaks new ground finally?

Either way, Tab Soap at least serves as an example of how innovation can promise to improve even the most basic of human habits, and help in the ongoing battle against infectious diseases.