How a Closed Landfill is Converting Our Trash Into Renewable Energy

How a Closed Landfill is Converting Our Trash Into Renewable Energy

SAN GABRIEL VALLEY, Calif.—Standing on a grassy hilltop of the Puente Hills Landfill is an old guard house. What was once the last line of defense against a Soviet Union air strikes, is now a relic of the Cold War-era Nike missile site. In the U.S., approximately 250 launch sites protected major metropolitan areas, 16 of them were located in Los Angeles County, according to the Los Angeles Almanac.

The defunct guard house watches over what once was America’s second-largest landfill.

Puente Hills landfill closed on October 31, 2013; however, it still employs LA County Sanitation District workers to maintain the 1,365 acres of land located in San Gabriel Valley. This includes the Materials Recovery Facility (MRF) that still actively sorts non-residential, commercial waste and recyclables.

Garbage Mountain, as it’s sometimes referred to, spans from the highest sealed trash deck (around 500 feet) down to the low-slung landscape that extends along the 60 freeway and the neighboring Hacienda Heights community.

Converting methane gas, a byproduct of the sunken trash, into alternative fuel is a big part of the landfill’s upkeep since its closure.

Jerrold Brandon is a senior sanitation engineer at Puente Hills and oversees the capture of methane gas from the underground gas wells. He’s worked in the waste-to-energy sector at the landfill’s on-site power plant for the past 31 years.

Brandon estimates the power plant has seven years of life left since they are no longer collecting trash or digging gas wells. The existing web of pipes and trenches capture the methane gas, which is turned into renewable energy and used to power the plant or sold to electric companies.

“The gas lines run back to the power plant and that’s what we use to turn the turbine, which creates the electricity,” said Brandon.

Leaky pipelines often plague the site. Controlling odor and emissions is top priority for Brandon and the sanitation crew to remain in compliance with California’s emission standards.

“We have to maintain it because it’s ours cradle to grave,” said Brandon.

Puente Hills Power Plant
Main power plant located on the Puente Hills landfill that's still active in producing electricity. Photographed by Jourdan Arnaud (Dec. 5, 2019)

NASA recently published a Methane Source Finder study after collecting data from California’s top methane source emitters since 2016. A research team from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. partnered with California Air Resources Board (CARB) and the California Energy Commission to survey 300,000 agriculture, energy and waste facilities using planes equipped with advanced imaging sensor technology to collect data.

According the survey, waste management accounts for 41% of the survey’s total methane point source emission sectors in California, driven by a small fraction of landfills. NASA’s team surveyed the Puente Hills landfill in 2016 and detected one methane point source from an energy infrastructure near the Materials Recovery Facility below the landfill.

Puente Hills landfill has largely been America’s model for modern waste management once the Sanitation District took over the private San Gabriel Valley dump site in 1970. From the outskirts, it’s hard to tell there is even a mountain of trash housed within the tree-lined perimeter. America’s disposable economy concealed from sight.

A hiking trail wraps around the western edge of the landfill and is open to the public. The Puente Hills Habitat Preservation Authority reintroduced native shrubbery to the canyons and runs a wildlife preserve to restore natural habitats.

Since its closure, the Parks and Recreation Department announced plans to convert the landfill into a community park over the next 30 years. Those plans have been stalled due to financing disputes between the Sanitation District and the Parks Department, according to Brandon.

For now, hikers roam the trails and pass by the restored guard house that overlooks the vast urban sprawl of Los Angeles and the surrounding counties. It stands as a symbol of the past and a renewed hope for the power to change and adapt as a society.

Puente Hills Hiking Trails
Hiker jogs the Puente Hills trail that surrounds the landfill. Photographed by Jourdan Arnaud (Dec. 5, 2019)
Back to Top