Life & Death of a Banana Peel

By Lindsay Sterling

It’s nice to know that our garbage gets carted away and we don’t have to deal with it anymore. But did you ever wonder exactly what does happen to it? We follow a discarded banana peel from the moment it’s thrown away until it becomes…but let’s not get ahead of ourselves.

Where does your garbage go? You just threw a banana peel into a can under the sink. The peel sits there at least for a couple days. If you’re unlucky, your dog scatters your garbage on the floor to remind you what you’ve been through that week: take-out Chinese, your daughter’s dirty diapers, a burned-out light bulb, a clear plastic bread bag. You transfer the garbage to a larger can in the garage. In the colder months, your banana turns nearly black and freezes. In the warmer months, it decomposes quite quickly. With in a couple of days, it’s brown, squishy, and hosts a family of fruit flies. Then you take the trash out to the street corner. Voila. As far as you’re concerned, it disappears into thin air. But where does it go?

In the garbage truck on the way to south Portland, your life’s debris joins that of your neighbors. Banana peel, meet your neighbor’s potato chip bag, rotten chicken bones, and dirty doll. And here’s your neighbor’s clump of bathroom garbage. Banana peel, meet Bob’s toenail clippings and Mary Anne’s hair collected from the shower drain. From highway 95 near exit 46, we can see the incinerator’s two smokestacks off to the west barely poking above the pine trees. The garbage truck turns into its final destination, Regional Waste Systems on Blueberry Road, off Route 22 just west of 95 and the pink Unum-Provident building.

The truck drives up to a blocky, gray building and dumps the neighborhood’s garbage at the bottom of an eight-story cement pit. Another truck dumps on top of it. Neighborhood trash, meet the commercial debris from L.L. Bean, Starbucks, and The Gap. The banana peel has turned into brown paste by now, but no matter. The end of its sad, physical existence is near. Within minutes, our banana peel will be blasted into molecular smithereens.

Mark Arienti, the environmental manager of the incinerator, and I are in a Plexiglas room perched at the top of the garbage collection pit, eight stories high and as wide as an office building. Arienti calls the pit “the bunker.” The bottom of the bunker is covered in plastic bags of garbage. In the summer with all the tourists here, 3000 tons of trash can fill the bunker up to two thirds of its capacity. To stay on top of the garbage flow, the plant must run 24 hours a day, 365 days a year, burning about 550 tons of trash each day.

A crane operator is in the room with us, listening to Van Morrison while doing his job. In his 12-hour shift he will use two joysticks, one in each hand, to transport 250 tons of trash up from the bunker into a chute that feeds the incinerator. As he maneuvers his joysticks, we watch a giant metal claw in the bunker chomp down on bags of trash. The garbage, some dripping and falling out of the claw, swoops 70 feet into the air before dropping into the feed hopper. Now would be a good time to say good-bye to our banana peel.

We walk out of the crane operator’s cabin onto metal grates on the seventh floor. “So where’s the incinerator?” I ask. Arienti points to the gray metal walls on either side of me. There are actually two incinerators, each eight stories high, and we’re standing in between them. Though the air smells unquestionably like hot garbage, my gag reflex never kicks in. The smell is just there, a tolerable presence in this dimly lit, all-metal, windowless, industrial space. The near-eighty-degree temperature where we stand, he says, is a nice perk for workers mid-winter, but hard to tolerate during summers.

With Arienti’s okay, I reach out and touch the wall of the incinerator. It’s very warm, like the hood of a recently run car. Arienti tells me that the banana peel is burning inside at two thousand degrees Fahrenheit. “It’s well insulated,” he says with a smile. In the fire our banana peel is changing form utterly, breaking apart into many things, each with its own path to follow.

The most unexpected of its new forms is electricity. A banana in the incinerator may be powering your reading lamp. An old ham may run your hair dryer. An old couch may power, fittingly, your TV. How does your banana peel turn into electricity? Above the fire in the incinerator there’s a network of pipes filled with water. The heated water in the pipes turns to superheated steam, which gets released out of the pipes to push the blades of a turbine. The magnetic fields in the turbine generate electricity. The incinerator sells the electricity to the power company, which in turn sells it to you. In a single day, the incinerator generates enough electricity to power the town of Freeport, and then some.

Also on the seventh floor, Arienti shows me a set of gauges and a monitor screen. This is where the plant operators control nitrogen oxide emissions, a contributor to smog. They spray urea, a chemical related in structure to ammonia and human urine, at a gallon a minute into the fire, which reduces nitrogen oxide emissions by 35 to 40 percent. Other systems in the plant spray chemicals into the fire that make unwanted airborne elements stick to the ash. For example, to prevent harmful mercury–what collects in our waterways, builds up in fish, and is believed to cause developmental brain problems in children–from leaving through the smokestacks, they spray powder-activated carbon to solidify the mercury in the ash.

I ask Arienti, “What is leaving through the smokestacks, right here in Portland?” In winter, as I watch gray smoke billow out of the smokestacks and merge with the clouds, I wonder what kind of pollutants might my banana peel–not to mention less natural garbage like an old couch or a plastic toy–may be sending into the air. Arienti assures me that over 99 percent of the air coming out of the smokestacks is simply carbon dioxide and water.

To prove his point, he shows me the control room where he points out eight computers that are monitoring various plant functions and the air leaving the stacks. Trace amounts of greenhouse gases (nitrogen oxides, sulfur oxides, and carbon monoxide) do get into the air, but not nearly as much as they did five years ago. The plant operators monitor the amounts according to rules set by the federal Environmental Protection Agency (EPA) and Maine’s Department of Environmental Protection (DEP), and regulate them by adjusting the injected chemicals mentioned above and the amount of garbage being put into the fire.

Now the only part of our banana that’s left is the ash. It gets quenched in cold water, drained, and sent to an ash landfill. The ash’s contents sound like a list from the table of elements: aluminum, arsenic, barium, cadmium, calcium, chromium, lead, mercury, selenium, silver, zinc. Again, the EPA and DEP monitor the ash content with a Toxicity Characteristic Leaching Test to make sure that the ash is non-hazardous. The ash turns as hard as cement and becomes highly insoluble, so there is little risk of leakage. Still, the ash landfill is encapsulated in a 40-millimeter-thick plastic membrane, which is in turn surrounded by nearly impervious natural clay, so no harmful heavy metals should reach the water table. Just to be extra sure, the groundwater that touches the membrane of the ash landfill is regularly tested during the use of the landfill and for a minimum of 30 years after its closing to ensure that our water remains safe.

Now what has become of our banana peel? It has become carbon dioxide that the nearby pines are breathing. It has become water which fish eventually swim through. It has become ash, buried in the earth. And let’s not forget, the light shining on that bunch of bananas in your kitchen.