EXCLUSIVE: Here's how COVID is detected in wastewater throughout CA

Luz Pena Image
Thursday, June 16, 2022
EXCLUSIVE: Here's how COVID is detected in wastewater
ABC7's Luz Pena walked through the Palo Alto Regional Water Quality Control Plant, which has been testing wastewater for COVID.

PALO ALTO, Calif. (KGO) -- Silicon Valley runs on data and, when it comes to the next pandemic, scientists are looking in a place where everything was once considered waste until now.

Jaime Allen walked ABC7 News through the Palo Alto Regional Water Quality Control Plant. This facility serves over 200,000 people across the Bay Area, but since the pandemic they've been doing more than clean millions of gallons of wastewater a day. They are playing a key role in detecting COVID.

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"A lot of people are using rapid tests at home and those tests results are not reported to the local health department. So, there is no way of them knowing how many people actually have COVID. Wastewater gives us a true picture," said Professor Alexandria Boehm, Stanford's Department of Civil and Environmental Engineering.

According to the CDC, "People infected with SARS-CoV-2 can shed the virus in their feces, even if they don't have symptoms." That's why this has become an effective indicator of COVID transmission.

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There are two million copies of the virus in every gram of wastewater, but once it gets to wastewater plants it's dead and no longer infectious.

Since COVID is neutralized when it reaches wastewater facilities, plant operators can collect samples without the need of PPE.

At the Palo Alto site the collection begins around 3 p.m. The sample is later sealed and stored in a fridge.

In the meantime, a group of couriers are driving to wastewater plants throughout the state collecting samples.

One of the couriers is Saul Hernandez. He collects samples throughout Northern California for Dalmatiancourier.inc.

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All the samples end up at Verily.

"The first sample will come in looking something like this. A mixture of liquid and solid. What we do is spin it at a super high speed, many thousands of revolutions per minute, and what we get left is just the solid portion that we are going to use for testing," said Bradley White, lead scientist for the wastewater project at Verily.

Verily processes over 30 samples a day from across the country and 16 from California wastewater sites.

The process to detect how much COVID is in a community is meticulous. Surprisingly, it only requires one sample per plant and ".3 grams" of solid from that sample.

Luz Pena: "This data represents how many people? (Pointing to a sample)"

Bradley White: "It depends on the sewer-shed. Our largest sewer-shed in Los Angeles there are 4 million people contributing to that sewer-shed. We are able to gain this information about everyone in that sewer sheds from this small sample that we take."

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The next step is to detach the virus from everything else.

"Those ball bearings physically disrupt the virus from the sample. So they'll free it up. Then the virus will also be encapsulated and that liquid that we put in breaks those encapsulations and frees the virus so we can detect it in the next process," said White.

One of the final steps lights up the sample that has COVID.

"If there is virus in there the droplet will floures. From there, we can infer how many people in our community have SARS-CoV-2," said White.

The entire process in the lab takes about 10 hours, including sequencing for specific variants -- a fast operation that Verily's co-founder, Jessica Mega, says is key to give health departments enough time to respond before a surge.

"Wastewater gives us an early warning signal. We don't want to wait until people get sick. They then become symptomatic and then get tested. With wastewater you can get ahead of that. Understanding what is happening in the community, understanding which variants are more prevalent," said Jessica Mega MD, MPH, co-founder & Chief Medical & Scientific Officer at Verily.

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Years before wastewater samples were processed at this scale, Stanford Professor Alexandria Boehm had the vision.

A team of research students started collecting wastewater samples from campus in early 2020.

That's now expanded to creating the Sewer Coronavirus Alert Network, a project that analyzes and releases data for 11 water treatment plants in California.

"We developed the measurement techniques and the technology and we needed to scale it, so that we could provide real time information," said Prof. Boehm and added, "We talk to the public health department pretty much on a daily basis."

This is how this team detected omicron more than a week before clinical samples confirmed the highly-transmissible variant in the Bay Area. Now they are focused on the next one.

"There is no more BA.1, which is the original omicron variant, and it's basically all BA.2, but we have now started to see BA.4 coming up in wastewater. We are watching that closely. If the levels increase and if it outcompetes BA.2," said Prof. Boehm.

Scientists are also using wastewater surveillance to detect other viruses in hopes to prevent future community outbreaks.


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