A Trip to the Landfill

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Working face of landfill

The working face of a landfill is where the day's waste is unloaded. Compactors drive over the trash, reducing the volume of the trash. Photo: Jennifer Berry, Earth911.com

The following is an op-ed piece by Earth911.com Staff Writer Jennifer Berry and does not describe the views or opinions of Earth911.

If you open the book “1,000 Places to See Before You Die,” going to a landfill probably isn’t there. It certainly wouldn’t have made my own “bucket” list – after all, Thailand and the Great Barrier Reef are much more exotic.

But after visiting one example of what all landfills could be like, well…perhaps my opinion has changed.

As part of our trip a few months ago to see just where “away” is – as in when we throw our trash away – a landfill was our final destination, as it also should be for our waste.

Central Disposal, the landfill that we visited, is a 400-acre facility in Broward County, Fla. Taking in 3,000 to 4,000 tons of waste per day, the facility is one of Waste Management’s (WM) oldest landfills at 45 years in operation.

Unlike the dumps of old (think: giant, unregulated holes in the ground), which are no longer in existence because of revisions and updates to the codes that regulate them, Central is at the forefront of landfill tech, tying together landfill gas-to-energy, an on-site waste-to-energy plant, and a number of reuse and recycling operations at each level of the process.

This kind of technology isn’t necessarily new or revolutionary, but seeing it all in action, and in person, was a whole different story.

View from the outside

It would be dishonest to say I had no preconceived notion of what going to the landfill would be like. But, it would also be dishonest to not tell you that I was, a bit, excited. The whole process sounded so unpleasant that my geeky curiosity, not unlike examining a particularly odd insect, got the best of me.

As we drove up to the entrance, I waited to see it: the giant pile of trash that you know is lurking within the facility. But even though that’s what a landfill is – a receptacle for our waste – it didn’t look like that at all. From where we were, it was a giant, green hill.

Rising up to 225 feet above sea level, the closed-off areas of the landfill (cells that are full and cannot hold more trash) are covered with many stabilization and drainage layers that culminate in tall, green grass.

I got out of the truck and walked around the top of the hill, feeling a breeze that was blowing the smell of the working face, where the day’s waste is currently being dropped, away from me – probably making my experience more pleasant. They were getting ready to unload waste from the nearby sewage treatment plant, and I have to say I’m glad I missed that part. But, from where I was standing, it was a nice view of the surrounding area.

As we drive around the landfill, we spot a model plane soaring overhead. As the highest point in the area, the top of Central serves as an excellent point to launch these planes. In fact, a local group called the Pompano Hill Flyers regularly flies radio-controlled planes on this windy slope and is the only public group allowed into the landfill without supervision, having already received special training in safety on the site.

The landfill is a place of interest for local groups as well, from senior communities and schools to doctoral candidates and homeowners associations. Central regularly has a waiting list for tours, which I’m genuinely surprised to hear.

People come from all over to see just what happens here. And while the landscape was rather nice, to find the real story, you have to follow the trash.

Landfill gas-to-energy

Landfill gas to energy

More than 350 wells cover the surface of the finished cells in the landfill, drawing methane for conversion into electricity at the facility's on-site power plant. Photo: Jennifer Berry, Earth911.com

To start off, here’s the basic route that trash takes when it comes to Central: Trash is first taken to the on-site waste-to-energy plant where power for approximately 50,000 homes is generated. Then, what waste couldn’t be processed there is brought to the working face.

It is dumped out, spread around the area, compacted, and then covered at the end of the day. When we saw this area, which was towards the end of the day, it was really rather small in comparison to the rest of the facility.

This process of layering and compacting trash creates an environment that is particularly effective for creating energy.

In landfills, trash that can decompose (food and yard waste, for example) breaks down anaerobically, meaning without the presence of oxygen. This decomposition process produces methane, both a powerful greenhouse gas and energy source, making its capture important on a number of levels.

Through a carefully crafted system of more than 350 gas wells which use a vacuum system to draw the gas from the closed-off cells, nearly 11 megawatts of energy (enough to power 9,000 homes) are produced and sold back to the grid from their generators on-site.

Central is one of 110 landfill gas-to-energy (GTE) projects owned by WM that create enough power for more than 400,000 homes across the country, and energy generation from waste is a huge priority for the company. By 2015, WM hopes to have a GTE plant in every landfill that it supports.

“It’s about recovering the resource,” says Lynn Brown, WM’s vice president of corporate communications as I take hopelessly sloppy notes during the bumpy truck ride. “It’s going to make the methane either way, and we think it should be exploited for a higher, better use than just flaring it off.”

Trash is certainly being utilized in interesting ways in this particular region. In fact, between the other waste-to-energy facility in the area and what’s going on at Central, 90 percent of the trash produced in Brower County is producing energy.

“There’s also a focus around taking all of this material that passes through our hand and making the highest and best use of it. So, sometimes that’s recycling, in some cases, increasingly, we’re investing in ways to make energy out of it,” Brown adds.

The quality of the gas collected there is high. The textbook collection rate for a GTE facility is typically a 60-40 split between methane and CO2. At Central, the split is closer to 55-35 because of the range of materials accepted (for example, construction waste will not break down and produce methane, meaning no energy can be collected from this type of material), which still yields a significant amount of energy.

Brown tells me that energy can be collected for decades. But after approximately 20 years, cells become “dry tombs” where the materials within lessen their decomposition to such a rate that energy can no longer be harvested.

It’s not a bad deal for WM – after all, they’re capturing a harmful greenhouse gas and turning it into power that the area needs. Creating energy is also an important revenue stream, as maintaining and building a landfill is not cheap. For example, lining new cells before trash starts going in is a costly, but vital, endeavor for protecting the surrounding area. Central is double-lined with a series of plastic and fiber barriers to keep the substances within contained, running WM up to $500 million per acre to line.

Reduce, Reuse

Road in a landfill

The landfill uses old roofing tiles and other construction waste to build and stabilize its roadways. Photo: Jennifer Berry, Earth911.com

Another surprising aspect of this particular facility is that once trash reaches it, it isn’t always directly discarded. Reuse abounds at the landfill, aiding in the daily activities that are required to maintain the working areas of the site.

For example, trucks moving to the active face drive on crushed, discarded roofing tiles, which are used to stabilize roads.

Also, rather than simply throwing it out, Central utilizes the ash generated from its on-site waste-to-energy plant as part of its obligation to add 6 inches of daily cover at the end of the day to the working face. And, from that same ash, large pieces of metal (which won’t melt down in the astounding heat) is separated from the ash to be recycled.

Large yard waste, such as giant tree stumps and logs, are also removed from the waste stream to be reused in various civic projects.

According to Jeff Roccapriore, engineer for Central and who has been our trusty guide on this excursion, WM is even starting to separate out recyclables at their transfer stations before garbage trucks even get to Central. “If our customer doesn’t separate it themselves, we’ll do it for them if we can,” he says. This additional search for recycling is swiftly becoming an important directive, and two new picking lines have already been established this year to separate out recyclables.

Although Central’s overall model may not be true for all landfills, it is a picture of what could be at sites across the country as sustainable technologies reach more and more facilities.

More money = more trash

Central didn’t always accept this current rate of 3,000 to 4,000 tons of waste per day. It used to take in much, much more.

In 2007, the facility brought in close to 10,000 tons of garbage per day. Today, that figure has been reduced by 60 percent.

“When the economy is good, people spend more money; they buy more things,” says Brown, “and more garbage gets created.”

Although the results aren’t typical, this relationship of prosperity to waste generation is especially tangible at Central.

Roccapriore notes that a great deal of this waste was construction-based, due to the surrounding area’s rapid growth before the economic decline. But he does not expect a return to those figures, even accounting for an economic upswing. “Those tons won’t come back, but we are finding value in those individual components [that make up the materials we receive],” he says.

Across the country, this prosperity-to-trash relationship is apparent. At the end of the second quarter in 2010, total landfill disposal across the country (tons in millions) was at 23.8, while it was 20.3 in the month of March. These rates compare to  June 2009, when figures were at 23.9, meaning that trash volumes have risen back to what they were almost a year ago as volumes tend to lag behind the economy by one to two quarters.

It leaves an interesting question for our own responsibility in the waste generation question – when the economy picks back up again, will our landfills start getting more trash? Or will we still remember the reduce, reuse, recycle mantra that has become increasingly more important over the last few years and keep levels low? Only time will tell.

And while landfills aren’t exactly prime vacation destinations, I am glad I got to see one. The amount of waste we create everyday is staggering, to say the least, but I’m excited that we’re doing better about re-thinking the concept of “waste” and making the most of what we can. Perhaps one day we’ll have recycling streams for every bit of our “garbage,” but for now, this isn’t a bad start.

In September, the Earth911.com Editorial Staff visited three facilities operated by Waste Management: a recycling center, waste-to-energy plant and landfill. This story is the third in a series analyzing the technologies and capabilities in play that create an efficient system to maximize the recovery and utilization of waste.

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