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Touring San Diego’s Miramar Landfill makes it clear that waste disposal is still evolving.
It was a gloomy morning at the Miramar Landfill, but the guides for our hour-plus tour had the sunny disposition of folks leading a tour of a lovely park or museum, not an enormous pile of trash. Those assembled for the tour (parents with kids, senior citizens, and assorted garbage nerds like me) piled onto a comfy bus to learn about the history and innovations in waste management in San Diego.
The tours are sponsored by I Love a Clean San Diego, the fearless litter-fighting organization that’s been helping people understand the impact of waste, trash, litter, and garbage for 70 years.
We’ve come a long way, as the tour guides cheerily discussed the disgusting waste disposal habits of yesteryear, which mostly consisted of burning or dumping whatever waste you had wherever you could get away with it. This led to dead animals polluting San Diego Bay and other unpleasantries. By the late 1800s, the City was trying to deal with its trash, but skullduggery abounded among the private firms they hired, and in 1919 San Diego passed “The People’s Ordinance” mandating City-run trash collection. By the 1950s, there were 30 or so dumps and a handful of incinerators around San Diego, and in 1959, the City opened the Miramar Landfill, in what at the time was a far-flung rural setting. Miramar is now centrally located, is the City’s only landfill, and is run by the Environmental Services Department.
As trash volumes increased throughout the 20th century, as a result of both increasing population and people generating more garbage per capita, trash became something of a crisis, both locally and nationally. In 1976, the feds passed the Resource Conservation and Recovery Act (RCRA), which set national standards for landfills.
Today, the Miramar Landfill is about 1,500 acres, roughly the size of the San Diego Zoo Safari Park, and though the wildlife in Miramar is abundant, it is less interesting (though it does boast lots of native plants and even endangered species). The overall impression driving around is of a very bland park with lots of big trucks, though you’ll have to take my word for it since photography is prohibited (the landfill being so close to the security-obsessed Marine Corps Air Station). Miramar handles the 5.6 pounds of trash per person per day San Diegans generate, and also offers composting, recycling, and a dedicated section for yard waste.
Today, the Miramar Landfill is about 1,500 acres, roughly the size of the San Diego Zoo Safari Park, and though the wildlife in Miramar is abundant, it is less interesting.
Trash from our black bins gets dumped onto a small active “cell” of the landfill, spread around and smushed down by bulldozers to about one foot thick, and then covered every evening with Enviro Cover, a thin plastic sheet that controls odor and deters scavengers. This creates what the guides described as a “lasagne” of garbage (waste lingo is generally euphemistic). Below, the many layers of rubbish extend roughly 15 stories down to a waterproof liner that catches the “leachate” (rainwater that flows through the garbage, creating “trash juice”) that is collected and treated on site, and then spread around to control dust. Also collected is the methane that results from anaerobic decomposition of organic material. Methane that would otherwise contribute to climate change is used to power about 90% of the landfill (though the cheery tour guides were shaky on the details of how exactly this worked).
Dirt used to be used to cover the trash daily, but that took up too much valuable space.
And space is valuable, as the City estimates that Miramar might only have 10 to 15 years of space left, one of the several reasons the City is working so hard to divert waste, with a goal of “zero waste” by 2040. The City estimates that over two-thirds of trash is now diverted. Viewing the process of the garbage being compacted to get covered, one sees a lot of cardboard and other recyclable materials that should be elsewhere; it’s obvious that people are not as careful as they should be in separating waste. Workers at the main gate and at the “tipping face” (where the trash is actually dumped) scan for prohibited items. But the tour guides put it bluntly: Once the garbage is buried, it will stay there more or less forever. Once a cell is filled, it is covered with earth and replanted with native flora.
A huge part of the diversion effort is the “Greenery,” which opened in 1986, and where yard waste is turned into compost, mulch, and wood chips for city parks; residents can also get these products for free. The Greenery is also where the organic waste from the green bins is composted. The green bins, distributed last year for household organic waste, are a product of state law (AB 1383) and have the dual purpose of reducing the volume of waste buried (extending the life of the landfill), and reducing the creation of methane. The waste is run through a grinder to ensure uniform chunks and then a magnet collects any metal waste. Everything else is arranged in long piles about 10 feet high (“windrows”) of compost that decay at about 150 degrees as landfill workers perfect the best recipes to speed up the process, like aerating the piles or adding water. The finished product is a rich, dark mulch, though depressingly flecked with plastic and other junk mistakenly added to the green bins, and which compost users have to pick out by hand. In the first full year of the green bins, the City collected over 150,000 tons of green waste, which became 70,000 tons of compost. This resulted in 145,000 fewer tons of regular, black-bin garbage, about a 17% reduction, indicating that the program is working as intended.
In the first full year of the green bins, the City collected over 150,000 tons of green waste, which became 70,000 tons of compost. This resulted in 145,000 fewer tons of regular, black-bin garbage, about a 17% reduction, indicating that the program is working as intended.
The recycling in your blue bins get sorted offsite, and mattresses, which are often dumped illegally, are collected here for recycling into products like carpet padding and insulation. Household hazardous waste like batteries, paint, and electronics are collected here, for proper offsite disposal, as are the “biosolids” that get piped in from the Point Loma and North City sewage treatment plants. The sludge is “dewatered” in a multistage process, and the dry nutrient-rich “cake” gets used as fertilizer.
The cheerful tone and colorful slang of the tours belie their serious aim: to get people to be more responsible about what they dispose of and where. While it’s obvious that the public needs to be a lot more careful about their rubbish, it is definitely encouraging to see how much work, ingenuity, and innovation goes into managing the Miramar Landfill.
I Love a Clean San Diego offers landfill tours periodically. And if you’re a garbage nerd, check out the book Wasteland.
