[Lex Computer & Tech Group/LCTG] COVID levels in wastewater

Sun Jan 15 19:43:17 PST 2023

This is from memory, not any citation I saved: Years ago, perhaps 20-25 years ago, connections of storm drains into sanitary sewer lines caused inflow into the Deer Island plant to have too high a ratio of liquid to solid waste.  As a result, the MWRA forced towns to separate stormwater sewer systems from sanitary sewer systems.  This was done – not perfectly, judging fromTed’s testimony, but to a major extent.

As to “noise” in the graphs:  fluctuations in daily or weekly rainfall could look like noise, even though it’s not random noise.
    – Mike Alexander

On Sunday, January 15, 2023, 8:56 PM, palbin24 at yahoo.com wrote:

Ted,With all due respect my understanding is combined sewer and storm drains have not existed in many modern subdivisions (newer than 150 years).
The “overflow” happens in older system much closer to the output pipe (old drains in Boston to the Charles River)

Peter Albin

On Jan 15, 2023, at 5:13 PM, Ted Kochanski <tedpkphd at gmail.com> wrote:

Michael,
On my street in Lexington -- there is one and one only sewer main it connects to houses as well as to the drains on the edges of the streetSeparation of sewer lines doesn't happen in most places
Ted
On Sun, Jan 15, 2023 at 3:03 PM Michael Alexander <mna.ma at yahoo.com> wrote:

I’d assume that “waste water” is water in/from sanitary sewers – hence, not mixed with storm sewer water (no longer, at least).

    – Mike Alexander

On Sunday, January 15, 2023, 2:44 PM, Ted Kochanski <tedpkphd at gmail.com> wrote:

John,
There is a big problem with this data being compared over long periods of timeSome of the waste water includes surface run-off and some mostly doesn'thence, since the y axis is a concentration of virus in the water -- if the amount of "active water" from households is diluted by surface run-off because of recent rain or even more complicating melting snow mixed with recent rain -- how can you tell?
I suggest that the data suggests that last year there was a real spike and that recently there is just "noise" in the system
Ted

On Fri, Jan 13, 2023 at 8:17 PM <jjrudy1 at comcast.net> wrote:

Don’t worry about the y-axis, just the shape of the curve.  The article gave no indication as to what is “good”.  In the later graph look at the winter spikes.  The big problem was a year ago.

John Rudy

781-861-0402

781-718-8334  cell

13 Hawthorne Lane

Bedford MA

jjrudy1 at comcast.net

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