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Comment by a45a33s | Hacker News Reader

its unfortunate that we'll never know what this data looked like in 2019 or before

Seems like it’d be a pretty flat, unremarkable chart.

Perhaps, but there have been reports of varying veracity hinting that COVID-19 was already in Western sewage, blood and autopsy samples in 2019. Who knows if that was contamination, flawed equipment, geopolitical shenanigans or legitimate data though.

The reason why these are mostly believed to be false positive is that all current covid-19 lineages (sequences) can be traced back to a single clone that (based on mutation rate estimates) appeared somewhere in late 2019. There may have been other lineages before that, but we seem to have no RNA sequence of those lineages, so we cannot put them in relation to any existing strain. One has to wonder, where are those 'alternative' lineages now, if they existed in the first place? Sure, they may have gone extinct in the great lockdown. But then one has to ask why did those went extinct while so many other virusses didn't. An a simple (occams razor) explaination is: they never existed.

Hopefully, otherwise we have other problems

thats an assumption that we have no way of confirming

It's a very safe assumption.

We can look at excess deaths (https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm) and the speed and locations it spread around the world and be fairly certain that if the virus were here in significant quantities in 2019 we'd have seen signs of it.

If memory serves, there was a city in Italy I think where they were able to verify that Covid was present in the city some time before the first reported case because they keep samples of the sewer water for awhile, and that allowed them to retroactively test for it.

That makes me wonder… where does the Covid in the wastewater go? Do we successfully filter it out of the wastewater before recycling it back into the ecosystem? Where specifically does filtered wastewater go, and how confident are we in the filtering process?

I am not at all an authority on this but I think they use UV light to kill it during one of the treatment steps.

Only in a relatively few places.

But it's not really necessary most of the time.

It's often done more for political reasons than technical ones, because it's easier for the public to understand and trust UV disinfection than the other, much more complex processes that are typically used.

Cobb County GA is an example of a plant that has large scale UV treatment right before discharge into the Chattahoochee River. But it's effluent is cleaner than the water getting pumped into their water supply.

A significant goal of wastewater treatment is reducing or eliminating pathogenic load. For a methods overview, see: https://www.filtsep.com/water-and-wastewater/features/pathog...

This paper discusses treatment and emergent pathogens:

"The Role of Wastewater Treatment in Protecting Water Supplies Against Emerging Pathogens"

https://www.jstor.org/stable/23803199

I thought direct chlorination played a larger role, it seems it doesn't.

(Heavy chlorination of water does result in post-treatment chlorine compounds being present, these are themselves an environmental concern. The bulk of the chlorine evaporates or is reacted relatively quickly. Chlorine also negatively impacts "digestors" which process residual organic matter in wastewater.)

UV, oxygenation, sunlight, filtration, and dilution are all utilised as well.

Viruses tend not to survive long periods of environmental exposure outside a host in most circumstances, though I'm not knowledgeable on specifics or exceptions.

Not sure what the water treatment plant steps are downstream, but I can tell you I've been processing SARS-CoV-2 positive wastewater samples for ages and managed not to catch COVID. Most of the gene fragments tested for in these studies are just that, fragments. The virus itself degrades pretty quickly under environmental stress (UV, heat, evaporation, etc).

I wouldn't be too worried about catching COVID from the water.

Maybe they have old samples?

I'm entertained by the idea that somewhere out there, the CCP sent Chinese James Bond to swipe archived wastewater with covid infected ones to prove that it wasn't in Wuhan, but nobody has tested it yet.

Or in 1889-1890.

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