FOX31 Denver

Denver metro wastewater reveals its highest COVID spikes despite dip in case count

ENGLEWOOD, Colo. (KDVR) – South Platte Renew, the third largest wastewater treatment facility in Colorado servicing 300,000 residents, is noticing something unusual in its COVID-19 data.

Facility director Pieter Van Ry and his team partner with researchers to count copies of the virus. They’ve been collecting data since March 2020.

“The loading at the wastewater generally is a little bit of a leading indicator [of] what’s actually being reported,” Van Ry said.

That indicator measurement has been realized across the country throughout the pandemic. But recently the amount of wastewater virus at South Platte Renew is not in line with the case count, data shows. Since late October, samples of southwest metro wastewater have contained the largest amount of novel coronavirus copies on record.

“What we’re seeing right now is the trend is actually heading up,” Van Ry said.

Two spikes from roughly a month ago show more than a million viral copies per liter of sewage. In most measurements, the recent uptick more than doubles what was measured in late summer and early fall.

Samples are collected twice a week from the rawest of raw sewage at the facility. The wastewater measurements far surpass the trajectory of case counts.

Courtesy: Biobot Analytics/ South Platte Renew

The surprising results at South Platte Renew come as confirmed case counts in Colorado continue to fall. Researchers suspect they are seeing more coronavirus in wastewater from those who are vaccinated who may never know they contracted the virus.

“That’s entirely a possibility that people aren’t realizing they have symptoms, yet they’re still shedding the virus,” Van Ry said.

Van Ry cautioned that people should not get too caught up in the recent spikes. It’s important to determine a trend. Trends require more time.

“You can’t really look at it from a week-to-week perspective,” Van Ry said. “We look at it as a month-to-month or, now, year-over-year trend.”

The latest South Platte Renew sample– from Dec. 5—shows a dip from the previous all-time high.