Homeschool Science: Field Trip to a Single-Stream Recycling Material Recovery Facility

Because we haven't spent quite enough time studying trash yet!

I don't know if you've ever thought about it before, but how our communities handle municipal solid waste is really fascinating, and it makes a terrific study for science or civics. For Will, this field trip is part of her AP Environmental Science study, specifically Unit 8: Aquatic and Terrestrial Pollution. For Syd, this is part of her Honors Biology study, specifically CK-Biology Chapter 12: Communities and Populations.

This is Ray's Trash Service, a single-stream recycling service in Indianapolis:

That's not to say that they don't take any sorted material at all--here's where they receive baled recyclables from some businesses:

Did you know that you CAN recycle shrink wrap? You can't just put it in your recycling bin, though--Ray's accepts baled shrink wrap from certain businesses.

There were so many epic big machines here!

Here is where all of the rest of the recycling is unloaded--it's a big mountain of unsorted recyclables!

Doesn't it sort of make you want to walk around on top of it and look for interesting stuff? No? Where's your sense of adventure?!?

Here's one of the Ray's trucks preparing to back up into the warehouse and add to the mountain:

Oh, and here's my favorite part of the field trip!

I'm happy anytime I get to wear a hard hat!

The recycling comes to Ray's unsorted, but is then sorted in various ways by various means. Here's where humans stand at a conveyor belt and sort recyclables by hand:

We were there during their break, but mostly there are humans here:

Whatever they pull out at their station, they put down a giant tunnel to a collection area on the floor below:

After the humans comes an OCC Screen. It's got big rotating wheels that carry big pieces of cardboard across it, while everything else falls below:

  There are catwalks around the facility, and when you walk them you can follow the path of various conveyors sorting various recyclables:

This is a trommel. It's got holes of different sizes so that different things fall through into different bins:

The warehouse is HUGE!

Here, we're following the path of paper being sorted:

And now we're on past more conveyors--

--check out all of those plastic milk jugs!

--and on to see where sorted materials are baled and then sent out of the facility:

These are all aluminum cans:

This is a specific type of paper:

Here's cardboard being baled:

Whatever actual trash has made its way to the recycling facility gets sorted out and put into separate bins that then go to the incinerator that we saw a bit of during our field trip to the landfill:

The reality of this recycling facility was so much more interesting than I'd imagined it would be--and I was already thinking it would be interesting, because I knew we'd get to wear hard hats! It reminded me in many ways of the Dixie Cup factory that my Pappa worked in and that I'd get to visit every now and then when I was small--all those conveyor belts and all that machinery! Do kids still get to go on real factory tours these days?

Or did they, before the pandemic?

Homeschool Science: Field Trip to a Landfill!!!

Want to see some frustratingly low-quality photographs of a landfill, taken on a foggy, snowy day through the window of a 12-passenger van by a person sitting in the middle of the back row?

Of COURSE you do! It's a LANDFILL!!!

This particular landfill has been in operation since 1971, and was sold to its current owners when expansive legislative changes meant that the landfill would have to make a lot of improvements to its infrastructure that the original owners balked at. One of those improvements is the cut-off wall that extends underground more than 91 feet until it reaches shale. It's intended to isolate the landfill from the surrounding ground and the watershed, so that leachate--remember Syd's adventures with leachate?!?--can't escape and contaminate the community. The wall doesn't extend above-ground, but you can see occasional markers that show it is.

The incinerator is a different waste disposal company next door; you can see their smokestack in this photo:

Fun fact: incinerators, themselves, are not waste-free. The ash leftover from incineration is toxic and also must be disposed of in a sanitary landfill such as this one.

Second fun fact: yesterday, the kids and I took a field trip to a recycling facility in this same city. When they get materials that they can't recycle, they send them to this incinerator!

Third fun fact: there might be a field trip to that incinerator in the works...

You can also see in the photo above the mesh netting that surrounds the landfill. That keeps the wind from blowing trash away.

Because the landfill is saving space for future municipal solid waste storage, they have some land that they lease to other companies. Below is a working quarry within the landfill; it supplies, among other things, the gravel for the roads that go over and around the landfill:

And here's the working section of the landfill! There's a specific grade to the sides of the landfill that must be maintained, and that's what limits the landfill's height. Here, a truck has just finished dumping another load of municipal solid waste onto the top of this section:

 And now the compactor is spreading the waste and then rolling over it to compact it. The compactor is VERY heavy and huge:

There would be a lot more to see if it wasn't snowy and foggy and grey, alas, but still, this was enough of a taste to get the idea, and the kids have a little more context for their understanding of municipal solid waste and how it's handled in a community setting.

It was VERY different from the recycling facility that we toured this week!

Homeschool Science: Make a Model Landfill, Fill it with Municipal Solid Waste, and Try Not to Poison Your Community

AP Environmental Science has SO MANY fabulous possibilities for labs and other hands-on activities. I am absolutely loving mentoring this study for Will, and hauling Syd along for the ride!

This particular hands-on activity comes from AP Environmental Science Unit 8: Aquatic and Terrestrial Pollution. For Syd, it also works for Honors Biology, using CK-12 Biology Chapter 12: Communities and Populations as a spine. Will read Living in the Environment Chapter 21: Solid and Hazardous Waste as her spine.

The main idea is that currently, there is no way to completely rid ourselves of solid waste, and therefore, it's important to find the most efficient, least environmentally impactful method to store municipal solid waste.

For that, you need a landfill! But what kind of landfill should you make? Ideally, your landfill should hold all of the municipal solid waste that your community produces, should have a barrier in place to keep all leachate from contaminating the ground or water, and should be capped to prevent scavengers and wind from spreading waste and rainfall from entering the landfill and therefore becoming contaminated, as well.

Here's a good diagram of a landfill.

Designing your dream landfill, building a model of it, and then testing that model is a fun STEM activity and hands-on science enrichment. I planned out a more casual version of this lesson, and the kids loved it!

The basic idea is that the kids each get a plastic bin, to which they add a 1"-2" sand layer and a 1"-2" soil layer. I provided the following supplies:

• Monopoly houses
• more sand and soil
• popsicle sticks (these are a trap!)
• homemade play dough (already portioned, and definitely not enough to solely use to make a landfill
• paper
• plastic grocery bags

I filled a pint Mason jar with cotton balls, then added green food coloring and water to the 2-cup line. This is our municipal solid waste!

The kids' challenge was the following:

1. Using the provided supplies, create a community that includes a landfill. The community should have at least a dozen houses.
2. The landfill should be impervious to rain and scavengers entering it, and impervious to solids and liquids leaving it. 
3. The landfill should hold at least one cup of municipal solid waste, which includes both solids and liquids.
4. The landfill should be able to survive a rainstorm and high winds without destruction or leakage.

Will had already read her AP Environmental Science chapter and watched most of the relevant videos in our AP Environmental Science playlist, so she had an advantage over Syd, who had only looked at the landfill anatomy diagram and read about solid waste storage more generally in her CK-12 Biology chapter. Regardless of background knowledge, though, this is still a fun engineering challenge, and I think you can see on the kids' faces how much fun they had with it!

Syd prepares the liner for her landfill.

Will falls into the trap by using popsicle sticks. They're a terrible choice for building a leak-free landfill!

At times, I felt more like a preschool teacher mediating children's work with sensory bins. After a long winter, the kids seemed to adore getting their hands dirty!

All those popsicle sticks! 

Syd's landfill is far larger than she needs for this challenge. I appreciate the room for growth, but it's going to suck trying to keep that whole landfill leak-free.

We add one cup of sopping wet cotton balls and green water.

Next, Will has to cover it and build a cap.

Popsicle sticks AGAIN!!!

Alas! The landfill has sprung a leak!

The engineer observes the problem and starts troubleshooting.

Meanwhile, in the next town over, the world's largest landfill receives its first cup of municipal solid waste.

Oh, dear! This community has just experienced a terrible rainstorm, and the cap on their landfill has taken a LOT of damage!

Syd adds the last dregs of municipal solid waste to her community's landfill.

Will the landfill hold?!?

It... will not. See that leakage? Syd has apparently foregone a liner entirely and instead relied just on the sand to hold the leachate.

This is a disaster! She's delighted.

If the landfill is this leaky already, what on earth is going to happen when it rains?

Wow. That's an environmental disaster, all right!

There seems to be a LOT of leakage. I wonder what the underlying ground looks like?

Oh, no! The soil of the entire community has been contaminated!

Chaos ensues, as the goddess of this little community seemingly decides to just give up and turn evil:

Will, her own landfill safely recapped with plastic, thought that Syd's crash-and-burn trainwreck of a landfill was HILARIOUS.

That plastic cap, though? Worked perfectly! Perhaps her community can take in the survivors from the other plastic bin.

Lessons were definitely learned about the importance of a leak-free landfill!

At the conclusion of this challenge, the kids washed the Monopoly houses and returned them to the game, threw away the play dough and plastic bags, and then dumped the rest of their landfill community--sand, soil, popsicle sticks, and cotton balls--into our compost. 

If you wanted to extend this activity, you could try to design and test landfills that deal with a variety of environmental challenges: a tornado or hurricane using a fan, a flood using more water, an earthquake using a shaker table, a population growth using more cups of municipal solid waste, etc. For us, though, this was a super fun way to always remember the importance of good design in a landfill, and what can happen when that design fails.

And the next day, we took a field trip to a REAL landfill!!!