One of the largest obstacles for the “toilet to tap” movement to overcome to truly take off as a solution to water supply shortages is public perception.

Researchers at the University of California-Riverside recently published a study focused around that public perception of recycled wastewater.

“It seems that this term (wastewater), and the idea of recycled water in general, evokes disgust reactions,” said Daniel Harmon, a graduate student and lead author on the study, in an article by UCR Today. “It’s important to make recycled water less scary to people who are concerned about it, as it is an important source of water now and in the future.”

What the researchers did is with a sample of 143 people conduct the first blind taste test of recycled wastewater. Taste is the remaining public perception obstacle with recycled wastewater since the safety of the practice has long been established and has been the focus of most of the research to date.

Treated tap water using the indirect potable reuse method was compared alongside conventional tap water and commercially bottled water. Participants were given the water unlabeled and in similar cups, and told to rank each on a 1 to 5 scale for taste, texture, temperature, smell and color. On top of that, researchers also considered factors that can affect taste perception — a person’s taste sensitivity which was gauged using paper strips coated with the chemical phenylthiocarbomide (finding it bitter indicates a greater sensitivity), and two personality traits that can determine preference, “Openness to Experience” and “Neuroticism.”

Researchers hypothesized that the three waters would all score equally, but recycled wastewater and bottled water ended up beating out the conventional tap water as more preferred.

“We think that happened because indirect potable reuse and bottled water go through remarkably similar treatment processes, so they have low levels of the types of tastes people tend to dislike,” Mary Gauvain, a psychology professor and co-author on the study, said in the UCR Today article.

The researchers’ overall conclusion from the taste test is that selling people on recycled wastewater should be focused around comparisons to bottled water and the similarity in treatment processes.

“We think this research will help us find out what factors people pay attention to in their water decisions, and what populations need to be persuaded to drink indirect potable reuse water and how to persuade them,” Harmon said.

Source: UCR Today