Narrator: More than a dozen trucks
unload food waste here every day,
80 miles east of San Francisco.
The city was the first in the US
to require everyone to separate out their compostable trash.
Fruits, vegetables, tree branches,
and cardboard decompose here
until they're ready to be spread
across surrounding farmland.
Now the city composts and recycles more trash
than it sends to the landfill.
That means San Francisco is saving water,
space, and chemical fertilizers
and reducing destructive greenhouse gases.
So, how does composting work
when it's servicing a whole city?
And why aren't more places doing it?
We went straight to San Francisco's compost pile
to find out if this model
can actually reduce worldwide waste.
An employee-owned company called Recology
collects all of the trash, recycling, and compost
that San Francisco throws away.
Since 2015, every home and business
has used a separate bin for their food and yard waste.
It ends up here, at this industrial composting yard.
Jose Lizarraga: It doesn't look pretty now,
but here in a little bit, I'll show you the pretty part.
Narrator: The process is designed
to mimic what happens in nature.
Robert Reed: It's just like leaves falling on the ground
around a tree.
But instead, we're using banana peels and coffee grounds,
we're making a beautiful, nutrient-rich compost.
Narrator: The whole thing takes 60 days,
and it does require machinery like this.
Jose: This one here is a Lubo screen.
What it uses is big rubber stars.
And all the organics fall through,
and everything else bounces
over the top of the stars as they spin.
Narrator: The separator weeds out most of the plastic
that people accidentally put in the compost bin.
That goes to the recycler or the landfill.
An 8-foot-wide trommel spins everything
to sort it again by size,
this time into smaller pieces.
The larger things pass by over the top on a conveyor belt.
Workers like Abi Morales pick out chunks of wood,
metal, or anything that is too large
to break down in the compost process.
Abi: A lot of people look at this as trash.
And for the most part,
that's what it is, trash.
But at the same time,
the other day, I was just doing my job,
and in the trash, I found a treasure.
$20.
Narrator: Abi used to work at a restaurant.
When the pandemic hit and the industry was struggling,
he made a career change.
Abi: It's a dirty job. Someone has to do it.
And I'm the guy that does it,
and I do it with joy.
Narrator: The next step falls
to the site's tiniest workers,
microorganisms that chow down on the organic material.
That's why airflow is so important.
Jose: That allows the microorganisms to breathe.
They're just like you and I,
they need water and they need air.
See where my hand is?
Right over the top of this air pipe.
What this does is it forces air up through the compost.
Narrator: The microbes also need just the right temperature.
Jose: We'll reach temperatures from 160 to the 130s.
These microorganisms are real finicky.
If you have too hot of a system, they'll die off.
If it's too cold, they won't grow.
Narrator: Pipes run underneath the compost rows
and draw harmful gases
to piles of chopped-up almond trees called biofilters.
Jose: This stuff, believe it or not,
came from across the street from one of the farmers.
Narrator: Microbes in the biofilters destroy these gases
and prevent them from releasing into the atmosphere.
Jose: The biofilter will last about three years
before it loses its composition
and we have to replace it.
Narrator: They spray water onto the compost rows
to keep the material moist throughout the entire process.
Jose: You've seen all the ugly part.
Now you're going to see the pretty part.
Well, at least what we call pretty.
Narrator: Two months after the scraps first land here,
this machine screens the compost one last time
to remove any leftover pieces of plastic.
Jose: Here's what you see in the finished product.
Nice moisture content.
A lot of organics in there.
Narrator: Every ton of food and yard waste
transforms into a little under half a ton
of finished compost.
That's because a lot of the water weight evaporates
in the composting process.
Recology sells it to farms, vineyards, and ranches
across the Central Valley and Northern California
and uses the profits to help fund its operations.
We talk about farm to fork.
We're thinking about fork back to farm.
Rather than it going to waste,
we put it to good use.
Narrator: This is San Francisco's main
waste-transfer station for compost and trash.
This 18-foot-deep garbage pit
used to get filled to the brim every day.
But now?
Robert: It might be 3 feet deep or 4 feet deep,
and sometimes we can see the concrete bottom.
Narrator: Today, San Francisco keeps
most of what it throws away out of landfills.
That's a big change from 25 years ago,
when California was running out of space to bury its trash.
Since then, San Francisco has composted
2.5 million tons of garbage.
That's enough trash to fill more than 13 Salesforce Towers,
the tallest skyscraper in the city.
We weren't very good at making compost in the beginning,
but we cut our teeth on that.
Narrator: The city incentivizes homes and businesses
to comply with composting laws.
Alexa: If you're a restaurant
and the majority of what you're discarding is organic
and you're not composting,
your refuse rate, your bill with Recology
is going to be through the roof.
But if you compost, it's going to be lower.
We're forcing you to save money.
Narrator: But composting doesn't only save landfill space.
It's also a climate solution.
In a landfill, food breaks down
in a tightly packed environment without oxygen.
That kind of rotting produces methane,
a harmful greenhouse gas 80 times worse than carbon dioxide.
Composting keeps that from happening.
And when it's spread on farms,
compost helps store CO2 in the soil.
Robert: So when you compost your food scraps
in San Francisco, you're actually helping
turn a vineyard into a carbon sink.
Narrator: And there's more.
Robert: Compost is a natural sponge
that attracts and retains water.
Narrator: California growers are willing
to try anything to save water
after more than 20 years of extreme droughts.
So, if composting reduces food waste and helps farmers,
why aren't more places doing it?
There are over 700 composting programs across the US.
Like San Francisco,
the city of Seattle and the state of Vermont
have also mandated composting.
And 24 states have laws in place
banning yard waste from landfills.
But the practice is optional in most places,
if a municipal program exists at all.
In Washington, DC, you have to drop off your food waste
or pay a company to pick it up.
New York City canceled its composting program in 2020.
It's due to restart in fall 2021,
but it still won't cover the whole city.
Alexa: That residential composting program
that was discontinued was funded out of their general fund.
So obviously it's competing with COVID relief funds,
competing with COVID testing funds.
That's a hard argument to make politically, right?
Narrator: San Francisco funds its program like a utility,
so customers pay Recology directly each month.
Alexa: So that creates that protection around our program.
Narrator: But composting still isn't the best solution
for solving food waste, according to the EPA.
It ranks composting second to last.
Alexa: From a carbon perspective,
we want food to be eaten
by people first
or not produced at all.
Narrator: About a third of food produced globally
still gets thrown out.
But even in a perfect world —
You would still have some food scraps.
You'd still have some banana peels
and apple cores and coffee grounds.
And all those things came from a farm,
and they ought to be made into compost
so they can go back to a farm.
Narrator: Starting in 2022,
the entire state of California
will require compost collection and food-donation programs.
That means building many more of these facilities
across the state.
If the state meets its goals,
it would save 26 million tons of organic waste
from going to landfills
and reduce greenhouse gas emissions by about 1% every year.
Jose: It's just important. It's the right thing to do.
We can't just keep burying things,
and, you know, the problem doesn't go away there.
We have to find solutions.