The most recent testing for evidence of COVID-19 in the city’s sewer system documented a significant increase in particles per liter in the east plant, putting that area in a red zone for uncontrolled transmission.
The east plant is the area generally east of New York Avenue and north of Oak Ridge Turnpike.
In the last test, the east plant was up to 2.4 million positive genetic particles per liter. That was an increase of almost 35 times from the prior weekly test result of 69,000 positive genetic particles per liter, according to information provided by Oak Ridge Public Works Director Shira McWaters at a City Council work session on Tuesday evening.
In the last tests available, the area around Oak Ridge High School was in the upper end of the yellow zone, where widespread transmission is imminent, and it appeared to be trending up toward the red zone of uncontrolled transmission.
Last week, Oak Ridge City Manager Mark Watson said there are two areas north of the high school, going up the hill, that feed into the system near the high school. Even with high school out for fall break the week before, COVID-19 was detected at a manhole where the flows combine, and there may be a situation to resolve, Watson said.
The sampling near the high school appears to have fluctuated widely between the green and red zones.
Scarboro, Turtle Park, Rarity Ridge, and Emory Valley all appeared to be either flat or in the bottom half of the yellow zone or lower, according to the data provided by McWaters on Tuesday. Rarity Ridge and Emory Valley were both in the green zone—actions controlling—or right on the border between the yellow and green zones.
Last week, the Oak Ridge City Council agreed to spend up to $70,000 on COVID-19 wastewater sampling with help from a company called Sirem, a division of Geosyntec Consultants of Boca Raton, Florida. The money will come from COVID-19 grant funds and the Water Works Fund.
Oak Ridge Utility Manager Patrick Berge said the city began testing wastewater samples for COVID-19 using Sirem/Geosyntec in July. The samples were used to set a baseline for COVID before the school year began. Samples are taken from Turtle Park Wastewater Plant, the Emory Valley Lift Station, the East Plant Lift Station, and at sites outside the preschool and high school.
“The results of this sampling have indicated fluctuating but increasing levels of COVID in the city’s wastewater,” Berge said. The data has been provided to the city and the school superintendent, as well as county health authorities, to help determine the proper response.
The samples costs about $450 each. The city spent $25,200 on COVID testing through the end of September and, with an average of six samples per week, could spend another $40,000 through the end of the year.
Berge told Council last week that the city has been been the sampling six sites around the city since the beginning of July, using COVID in the wastewater as a proxy for transmission of the virus in Oak Ridge.