As if you weren't worrying enough already, here's a little something that I ran across through monitoring activity on the American Society of Healthcare Engineers discussion boards: https://www.id-hub.com/2018/10/17/hospital-plumbing-reservoir-resistance-interview-amy-mathers/, "Hospital Plumbing as a Reservoir for Resistance". This is both a podcast and transcript of an interview with an infection control doctor and microbiology researcher who specializes in how microbes develop resistance to antimicrobials. I didn't want to add this to the current string on antimicrobials in the Green Gurus forum because it is a little deep in the plumbing weeds. Sooo, here's a geek-fest for you, fellow nerds.
It turns out that hospital plumbing systems may be the perfect place for the wee beasties to form colonies and swap out antimicrobial resistant DNA. The host environment is the "biofilms" that form in wastewater drain systems. The researcher refers to it as a "superbug party". And the wee beasties are capable of moving upstream at about an inch per day - so they are literally climbing back up out of the sewer into "our world" on this side of the p-traps and toilet bowls.
And here's where there is a possibility of collision with water efficiency in the green building world. As we move to lower flush volumes and lavatory flow rates, the velocity of the fluid moving down these drainlines is reduced. One way to reduce biofilm accumulation is to "erode" them with higher speed flows over them - either with greater slopes in the drain piping or in higher volumes of flow in the confined space of the pipe (greater velocity).
