[Reading Science] Sewage Testing Robot That Prevented the Spread of COVID-19

Wastewater treatment plant in San Diego, California, USA. Photo by UC San Diego.

[Asia Economy Reporter Kim Bong-su] Since the global outbreak of the COVID-19 virus began in January last year, public health officials have struggled with the difficulty of tracking the spread of infections or predicting where outbreaks might explode. However, a case that attracted attention involved installing an automated COVID-19 virus testing robot at a wastewater treatment plant to prevent a large-scale outbreak.

According to 'UC San Diego,' published on the 6th by the University of California San Diego (UCSD) in San Diego, USA, a research team led by Professor Rob Knight at this university developed an automated wastewater testing robot system that can test 24 wastewater samples every 40 minutes to detect the presence of the COVID-19 virus. The method involves extracting the genetic material (RNA) that makes up the genome of the COVID-19 virus from wastewater samples and confirming it through polymerase chain reaction (PCR). This system boasts accuracy and speed sufficient to identify the presence of one COVID-19 patient in a single building housing 500 residents. In particular, the fact that asymptomatic infected individuals also use restrooms and that a relatively large amount of the COVID-19 virus remains in feces is considered an alternative to prevent silent infection spread.

In a paper published on the 2nd in the American Society for Microbiology journal 'mSystems,' the research team emphasized the robustness of the wastewater treatment robot system, stating, "The occurrence of COVID-19 infected patients in San Diego could be analyzed with excellent accuracy on a weekly basis and fairly accurate on a three-week basis."

During the development of this robot system, the research team also played a significant role in preventing the spread of COVID-19 infections on campus. To study the wastewater-based epidemic prevention system, the team collected and analyzed more than 100 wastewater samples daily from over 300 campus buildings starting last summer.

About a month later, on a Friday afternoon, a sample collected from a campus area tested positive for the COVID-19 virus. The research team immediately informed the campus authorities, who then sent text messages within 14 hours to more than 650 people, including members and related personnel of the associated buildings, urging them to promptly undergo COVID-19 testing. Ultimately, two asymptomatic infected individuals were identified among those tested, and the campus authorities isolated them, preventing a large-scale outbreak. Thanks to this, the COVID-19 infection rate on this university campus, which houses about 10,000 students, remains below approximately 1%, significantly lower than the surrounding areas and most other university campuses.

Building on this experience, the research team developed a wastewater-based epidemic prediction system for the entire city of San Diego. Although San Diego is a large city with a population of 2.3 million, all wastewater is processed at a single wastewater treatment plant. However, collecting samples of the COVID-19 virus diluted in the enormous volume of wastewater flowing into the treatment plant daily was a very challenging task.

A member of the research team said, "Unfortunately, we could not obtain the same results from wastewater samples as from swabs taken from patients' noses," adding, "The samples we obtain are highly diluted. Just think about how many people dispose of wastewater and garbage." To address this, the team developed an automated robot capable of collecting and analyzing 24 samples every 40 minutes, improving speed and accuracy.

Professor Rob said, "I hope wastewater-based epidemiology will be more widely adopted," adding, "Early warning systems for rapidly spreading large-scale diseases are especially useful for communities vulnerable to infectious diseases due to limited access to diagnostic systems and fewer opportunities for social distancing and isolation."