Clemson University monitors virus levels in sewage at three wastewater treatment plants to provide information on the extent of infected individuals at the community level. One on campus services the campus community plus a small subdivision located within the City of Clemson. The Cochran Road treatment plant services the City of Clemson to the west and north of Highway 93. The Pendleton/Clemson treatment plant services the Town of Pendleton and the City of Clemson that is east and south of Highway 93. Samples are collected over a 24 hour period (representing a “composite”) on a weekly or bi-weekly basis from the “headworks,” the location where all of the sewage enters the treatment plant.
The detection limit is ~1,000 copies per liter. When concentrations are below ~10,000 copies per liter, it is unlikely that there is active transmission in the “sewershed.” Between 10,000 and 100,000 copies per liter, there is reason to pay close attention to the potential for transmission; these levels can serve as an early warning sign that the virus is starting to spread exponentially. Levels above 100,000 copies per liter are associated with rapid increases in the numbers of infected individuals. Levels above 1,000,000 copies per liter are associated with numerous individuals within a community who are infected and shedding the virus. Additional samples are being collected within the campus sewershed to identify areas where infections may be concentrated.
Key for Summary Chart Below
Concern Levels:
0 = virus is below detection; infected individuals may be present, but virus levels are too low to detect
I = virus is above the minimum detection level but still at a low concentration; watch for increasing trends (4,000 to 9,000 copies per liter)
II = virus level of concern; pay close attention to a potential for active transmission ( 10,000 to 99,000 copies per liter)
III = significant concern; large numbers of infected individuals are likely (100,000 to 999,000 copies per liter)
IV = major concern; high numbers of infected individuals (>1,000,000 copies per liter)
Other Notes:
"-" means no sample was taken on that date
"BLD" means below the detection limit, which is typically ~4,000 copies/L
"AR" means awaiting results of a sample that has been sent to the lab
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