Microorganisms Are Cleaning the Water You Drink

The organisms we highlight on this channel
are all aquatic, they must be submerged in water in order to thrive. Residing in ponds, swamps, rivers, and oceans,
but also places that we don’t think of as bodies of water…places that are simply wet. When you’re a microbe, the thin film of
water on a snail’s back, or clinging to moss on a tree, can be a deep well of that
good stuff. Of course, we humans are also dependent on
water, in a sense…our cells are aquatic. We carry our rivers inside of us. And to fill our internal aquatic environment,
we drink. We also bathe in water, we cook with it, clean
with it, flush with it, and we make things with it. And when we’re done with water, the result
of our use of it is something we call wastewater: a mix of sewage, storm runoff, and other water
that has, in some way, come in contact with us. And, you know, less idyllic than your local
pond, wastewater is nonetheless a promising habitat for many a microbe. That’s part of what makes wastewater dangerous,
both for us and the environment. Diseases born out of bacteria, viruses, and
parasites can thrive in wastewater, which may also be filled with pollutants like metals
or the ingredients of our own pharmaceuticals and toiletries. And should the wastewater come in contact
with different ecosystems, the combined decay of organic matter and excess of nutrients
can create a chain of events that depletes oxygen from the water and affects the balance
of life previously maintained there. Dealing with wastewater has inspired engineering
across civilizations, from Mesopotamian stormwater drains to Mohenjo-daro latrines to Roman sewer
systems. Those have all built up towards our modern
wastewater treatment systems that clean the water, a feat of engineering that is nonetheless
built on microbial ecosystems whose history is much, much more ancient than our own existence. Bodies of water have to deal with pollutants,
whether they be the product of local shifts in nature, death and decay, or just plain
old fashioned feces. To us, these bits of organic matter are contaminants,
but to microbes, it’s a veritable buffet, leading to a process called self-purification. Bacteria, coming from the water or the waste
itself, shape this self-purification, consuming organic and inorganic matter while producing
compounds that benefit their neighbors. As they eat, the bacteria grow and divide. But just because this water is full of waste
doesn’t mean that the bacteria within it is immune from the drama of the food chain
that dominates nature at all scales. The waste-consuming bacteria become plentiful,
creating an attraction for various protozoa that have a range of dining habits. Peritrich ciliates, like Vorticella and Epistylis,
use a ring of cilia around their mouths to create tiny vortexes in the water, allowing
them to draw in and consume their bacterial prey rapidly. You might also find amoebas dining on bacteria,
crawling and increasing in size and number. These protozoa themselves then become the
prey of multicellular organisms like rotifers, water bears, and nematodes, and the excretions
of those organisms provide waste that further feeds the bacteria whose excretions provide
waste that further feed the bacteria. The consuming done by unicellular and multicellular
organisms helps clear the water, creating an ecosystem that doesn’t just feed, it
cleans. We are then living in a world that has its
own built in wastewater treatment system, but not necessarily one constructed to handle
the large volumes of wastewater created by dense gatherings of people, whether in the
form of towns, cities, or industries. And so we’ve created sewage treatment plants
that are, at their core, these same ecosystems recapitulated in an industrial setting, with
reactors full of microbes consuming and being consumed as the particulates of waste are
eaten and broken down. The primary difference between how this works
in nature and how it works in reactors is that we can control the reactor, tuning the
temperature and oxygen levels to keep the microbes happy and cleaning. One of the common methods used in wastewater
treatment is called activated sludge, which is sludge, but alive with bacteria, fungi,
and protozoa. When mixed with wastewater, that sludge becomes
a version of the self-purifying ecosystem from nature. The microbes consume the waste or each other,
clumping together into particles called flocs that settle to the bottom as a new mass of
activated sludge, with clearer water floating above. The activated sludge can be removed and potentially
even reused, while the cleaner water goes through more cleaning to be ready for release
back into the environment There are so many ways that we have learned
from or taken inspiration from the world around us, whether it’s the colors, the sounds,
or the creatures who spark our imaginations. But wastewater treatment is probably one of
the most important. Indeed, wastewater treatment is the largest
industrial, reactor-based use of microbes, even beyond brewing or baking. One recent study analyzing about 1,200 samples
of activated sludge from 23 countries found that there about 1 billion types of bacteria
represented around the world, with only a fraction of a fraction of a fraction of a
percent representing species that we have even begun to study. While not a particularly glamorous job, our
modern towns and cities are built on sludge and microbes that, by just living their own
lives and eating what looks good to them, make our clean water possible. Thank you for coming on this journey with us as we explore the unseen world that surrounds us. And thank you as well to all of our patrons on Patreon. We are tremendously grateful that we can share our enthusiasm for microbes and also wastewater treatment with the world, and our patrons are the reasons why. if you want to see more from our Master of Microscopes James Check out Jam and Germs on Instagram And if you want to see more from us, there’s probably a subscribe button somewhere nearby.

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