Cool Thesis of the Week: Marie Perez
Marie Perez ’12 is rooting through garbage for her thesis—and finding money.
Portland has an interesting history of waste disposal, says Marie Perez ’12. The Alphabet District in Northwest is built on compacted trash over an old wetlands, and there was a time when people expected the city’s rivers to be “cleansing, self-healing entities.”
The past year has seen another development: In October 2011, Portland added a significant composting program, and cut trash pickup from every week to every two weeks. The relative benefits and detriments of this program for the city, collectors, and Portland residents are the subject of Marie’s spring-fall Economics thesis, which she is writing with professor Noelwah Netusil.
“It’s just kind of changing the composition of our waste flow,” says Marie, who is from Cypress, Texas. Along with an increase in composting of food scraps from vegetable peels to chicken bones, she says, the reduced trash pickup has encouraged residents to recycle more, to keep their garbage bins from getting too full. The “big deal” of the program is that recycling has increased by 25%, she says.
This has significant environmental impacts. Rotting trash in landfills emits methane – the same chemical emitted by cows – which has greenhouse gas effects. When food is composted, Marie says, methane is removed from it, and it doesn’t escape into the atmosphere.
However, some economic complexities also kick in. “Whether or not that’s good for the haulers depends on the price of recyclables,” she says. Private collectors buy the rights from the city to collect recycled materials, which they then sell by weight to private recycling centers. Since the price of recyclables changes, collection agencies don’t always profit from higher amounts of recycling.
One place collectors do encounter more certainty is in the garbage cans. With biweekly pickup, “there are fewer garbage cans that are under-full,” Marie says. This allows them to better plan their pickups, reducing their costs. However, the consistently reduced trash levels can actually mean more costs for Portland. The city pays landfills to take its trash, has a contract to send a minimum amount of trash. “We’re not sending enough garbage to them anymore,” says Marie. That means the city has to pay a fee to the landfills.
For Portland residents, Marie says, “only about 20% of residents saw a rate hike, but this
year it’s likely that a greater percentage of residents will see their rates increase, albeit minimally.”
But overall, she says, “it seems like it was really effective.” Though much of the rationale is environmental, she says, “I think it also makes sense” economically. And Metro, the regional governmental authority, reinvests a portion of their profits such as from this program in projects like landfill rehabilitation. “I’m not going to be able to say… this was the most efficient way of achieving these ends,” she says, but the ends are being achieved.
So is it worth it? “If you believe it’s worth it to capture this much methane… if you believe it’s worth it to rehabilitate wetlands,” Marie says, “then the answer is yes, definitely.”
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