What happens to nanomaterials that get into our wastewater?

About the Author: Jacob Metch is a PhD student in Civil and Environmental Engineering at Virginia Tech. Check out his profile on the VTSuN student page.

Well it’s SUMMER TIME!! OH YEAH!!  Time to pack up and head to beach to get some sun.

Don’t forget to pack some sun screen. If you’re anything like me, if you don’t wear it you’ll be burned and peeling which is seldom a good look.

I also have to pack my assortment of odor neutralizing clothing so I don’t scare everyone away on the beach.  Oh, and some snacks for the trip out there, Power Aide and Peanut M&Ms always do the trick.

It turns out that most of the products that I packed for my trip have some sort of nanomaterial in them!

Nanotechnology is on the rise
Nanotechnology is on the rise

Now if you don’t know what a nanomaterial is, go check out this previous post and come back here.

Because of their special properties over traditional materials, nanomaterials are being used more and more in consumer products.

A few examples of products that may contain nanomaterials
A few examples of products that may contain nanomaterials

Some examples of these products are clothes, cosmetics, candies, lotions, appliances, sun screens, and much, much more.  For a more detailed list, you could go check out the inventory of consumer products containing nanomaterials. You may be surprised to see many products you have at home contain nanomaterials.

Eventually, it all washes down into the wastewater...
Eventually, it all washes down into the wastewater…

As we all know, these products can be awesome.  However, when we wash our odor fighting clothes, or shower after slathering on our sun screen, or excrete drinks and candy, the nanomaterials in these products wash out and wind up down the drain.  These nanomaterials are then carried to the wastewater treatment plant.

Meanwhile, at the wastewater treatment plant...
Meanwhile, at the wastewater treatment plant…

Wastewater treatment plants are really cool places where hard working bacteria happily eat our nasty pollutants in the water.  What we’re left with is clean water that can be sent out to the environment to be used again some day.

Here come the nanoparticles!
Here come the nanoparticles!

But what happens when the number of nanomaterials in products keeps increasing, washing a larger amount of nanomaterials into our wastewater treatment plants?

Since a lot of these nanoparticles (such as silver and titania nanoparticles) show antimicrobial effects, their presence may affect how well these bacteria work at cleaning the water.

That is an important question that needs to be answered by researchers.

What now??
What now??

Researchers have been focusing on this question, but have come to different conclusions.

Scientists have noticed that silver nanoparticles affected the communities of microbes that live in wastewater differently than silver ions do (Yang et al. 2014).

However when another research group did a similar experiment adding silver ions and silver nanoparticles to wastewater, they noticed some negative effects to the microbes, then a quick rebound of the microbial communities! Therefore, they were optimistic about silver nanoparticles in wastewater (Alito et al. 2013).

It is clear we need more information about this topic before making up our minds on nanomaterial safety in wastewater.

So check out the inventory and think about what the products you own may be contributing to your local wastewater treatment plant.  And stay tuned to the VTSuN blog to learn more about this emerging technology and how it can help you pack for the beach.

References:

Alito, C. L. and C. K. Gunsch (2013). “Assessing the Effects of Silver Nanoparticles on Biological Nutrient Removal in Bench-Scale Activated Sludge Sequencing Batch Reactors.” Environmental Science & Technology 48(2): 970-976.

Yang, Y., J. Quensen, et al. (2014). “Pyrosequencing reveals higher impact of silver nanoparticles than Ag+ on the microbial community structure of activated sludge.” Water Research 48(0): 317-325.

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