Imagine a city of almost 9 million people that shuts down its only landfill overnight. That is exactly what Mexico City did last month—and nothing has gone according to plan.

If there even was a plan, that is.

Since Mexico City Mayor Marcelo Ebrard ceremonially padlocked the gate to the giant Bordo Poniente dump on Dec. 19, city officials have struggled unsuccessfully to explain where all the city’s garbage will go—12,600 metric tons a day. They’ve sketched hopeful forecasts of how much waste will soon be recycled, turned into fuel for cement companies and converted into compost. And they’ve cited what they expect could be the shutdown’s most important benefit: a project to capture methane gas from the landfill and convert it into energy.

Such a project, to be sure, would promise an impressive combination of power generation and greenhouse-gas reduction. City officials say methane created by the Bordo Poniente’s decomposing waste accounts for about 20% of the city’s total greenhouse gas emissions. They estimate that burning it in a biogas plant would reduce those emissions by 2 million tons of CO2 equivalent annually. And during the first five years of the project, power from that plant could meet the electricity needs of 35,000 homes, according to the Clinton Climate Initiative, which is collaborating in the work. As Ebrard nears the end of his six-year term, shutdown of the landfill and construction of a biogas plant would help the city reach its broader goal of reducing carbon emissions in the period 2008-12 by 7 million tons, or about 18%, city environmental officials say.

But on the ground here, the transition away from the Bordo Poniente has not followed a coherent script. With backlogs hours long at the city waste collection centers and trash piling up on street corners, officials have resorted to dumping the trash back in the Bordo Poniente—a temporary measure, they say.

Eventually, they forecast, the waste will be deposited in landfills in outlying areas of the surrounding State of Mexico. Plans for this were held up in the first weeks of January by protests in neighborhoods near these alternate landfills. Following negotiations, officials in the State of Mexico have agreed to take the waste.

In the meantime, at the Bordo Poniente itself the scene has barely changed. Officials have promised that some 1,500 trashpickers, called pepenadores, will be allowed to continue working at the site as they have for decades, separating garbage to recover plastics, glass, paper, metal and any other recyclable materials. They make no salary, living off what they can collect and sell.

Recycling rate low

In the Bordo Poniente’s separation plant, waste trucked from the city’s 13 collection centers is piled onto three conveyer belts on a raised platform in a dimly lit shed. Under strip lighting, the pepenadores sort through the garbage as it rattles by, dropping recyclables into giant bags below. Gabriel Reyes, a supervisor at the plant, estimates that no more than 10% of the waste is collected for recycling.

The rest was dumped at the Bordo Poniente before it was closed, but will now be trucked to the new alternate landfills hours away. The city has committed to keeping the separation plant open, along with two other similar facilities. But the trashpickers are just the end of the line in a long chain of informal workers who make their living from trash, beginning with “volunteers” who ride atop neighborhood garbage trucks to sort through household waste. It is a vast subculture that is at odds with the idea of modern waste management.

Some experts question whether the Bordo Poniente, which holds 72 million tons of waste, should have been shut at all. “With investment, it could have lasted many more years,” says Gabriel Quadri, an environmental consultant and former director of Mexico’s National Ecology Institute. Garbage could have been placed on the older parts of the dump, where the waste has not been piled as high. “They never did this, and now it is chaos,” Quadri says.

Others point to the lack of planning and warn that shutting the landfill brings new risks. “It is very difficult to believe that they could close the Bordo Poniente without having any certainty where they could take the garbage,” says Gustavo Alanís, general director of the Mexican Center for Environmental Law (Cemda). The problem “was not viewed in its full dimension and other clandestine dumps could spring up.”

Still, he points out that Mexico City is not alone in its failure to deal with its garbage. “One-third of the waste in the country is not controlled,” he says. “You have to put it in context. The problem is national.”

Officials insist they are on the way to reducing the 12,600 metric tons a day that were dumped at the Bordo Poniente. Fernando Aboitiz, the Secretary of Works and Services for the Mexico City government, says the first step was to eliminate some 5,000 tons that were illegally brought in for disposal from other states.

Progress on composting

Plans last year to pay garbage collectors extra for organic waste revived a largely ignored waste-separation law in 2004. The waste goes to composting centers, including one at the Bordo Poniente, and has reduced the amount that has to be dumped by another 2,800 tons, Aboitiz says. (Mountains of compost outside Bordo Poniente’s plant raise the question of whether demand will meet supply, however.)

This month, the city also announced that it would set up sidewalk “islands” where residents could separate and leave their garbage in special receptacles.

Aboitiz says 200 of these collection centers would be installed by the end of February, increasing to 500 by July. By improving separation, the city will be able to recycle and compost even more of its waste.

With sales of waste to cement maker Cemex to use as an alternative fuel in its kilns, improved recycling and more composting, Aboitiz says that by as early as June, the city will need space to dump only 2,000 tons a day.

But Quadri is skeptical of the city’s numbers. The market for recycling is not well developed in Mexico, he says. Aside from paper and aluminum, less than 10% of plastics, tetrapak and glass is recycled. “There isn’t the infrastructure, the markets, the pricing or the regulation for this to work,” he says.