Landfill Trucks Dump Diesel for Natural Gas : Technology: Puente Hills facility harnesses methane from refuse and turns it into clean-burning fuel. Operators hope to convert entire fleet.

In the not-so-distant future envisioned by Puente Hills Landfill operators, San Gabriel Valley dump trucks will be powered by the same stinky trash they pick up each day.

That is, instead of heading to a diesel pump when the tank gets low, the trucks would fill up with trash gas--albeit highly refined--while dumping at the landfill.

Experts say dump trucks equipped with engines that burn such gaseous Jfuel--compressed methane--will spew fewer pollutants into valley neighborhoods than the smoke-belching, diesel-fueled trucks used today.

The vision stems from what landfill officials say is the nation’s first facility to produce and dispense a high-grade fuel derived from landfill gas. The gas, which is a combination of methane and carbon dioxide, is processed to yield methane that is compressed and then stored for use in vehicles equipped with engines that run on compressed natural gas.

Natural gas, which is typically found near deposits of fossil fuels, is mostly methane, usually about 90%, but may contain some other hydrocarbons, such as propane or ethane. The processing facility at the landfill has produced natural gas containing up to 98% methane, a purity level that officials say is ideal for use in compressed-natural gas engines.

When burned, officials said, the processed landfill gas produces fewer emissions than diesel or gasoline.

The technology to produce it is “revolutionary because it takes what is normally considered waste and creates an alternative fuel,” said Henry Wedaa, chairman of the South Coast Air Quality Management District board of directors and mayor of Yorba Linda.

“We win twice--with reduced landfill gas emissions and reduction of emissions from fossil fuels,” he said.

For years the landfill’s operator, the Sanitation Districts of Los Angeles County, has extracted gases created by decomposing trash buried deep in the dump. Regulations require the dump to extract and burn landfill gases to control odors. The gas is piped to a power plant at the landfill that generates electricity for about 100,000 San Gabriel Valley homes.

Today a tiny portion of collected gas is being processed, compressed and stored for use in vehicles equipped with very costly engines that run on natural gas only.

The county has spent about $1 million to build the natural gas processing plant and a pump--fashioned after the type used at gas stations--that can quickly fill a vehicle’s natural-gas tanks.

Officials hope their new facility, a one-year demonstration project, will prove that it is feasible to convert landfill gases into a fuel for low-emission natural-gas engines used in large trucks, including trash haulers and earth-moving vehicles used at the landfill.

Over the next year officials will monitor the performance, maintenance costs and emissions of four vehicles equipped with engines that run exclusively on natural gas.

The Sanitation Districts has installed special natural-gas engines and tanks in a large water truck and a pickup used at the landfill. Also, the landfill is using a $190,000 grant from the South Coast Air Quality Management District to convert the engines of two dump trucks owned by private trash haulers to natural gas.

Landfill officials hope that as the landfill and numerous cities and government agencies switch to natural gas-powered vehicles, the hefty price of engines that burn the gas will fall. Today, a diesel engine for a dump truck costs about $16,000, compared to about $70,000 for an engine that runs on natural gas.

In any case, landfill officials say, they hope to eventually convert their own fleet of pickup trucks, water trucks and earth-moving machinery to natural gas. Experts say natural gas is about 30% less expensive to produce than gasoline and about 20% less expensive than diesel.

And Sanitation Districts engineers hope to demonstrate that landfill-derived fuel can reduce engine emissions--including nitrogen oxides and particulate matter--by at least 60% while maintaining normal vehicle performance.

How long such experimentation can continue, however, rests largely on when the landfill will close. Engineers say the landfill holds years worth of natural gas for both landfill vehicles and waste haulers.

But the dump’s operating permit expires Nov. 1 and several groups have sued the landfill over an environmental impact report that supports the county’s plan to expand the landfill.

The county’s planning agency, the Regional Planning Commission, has voted to extend the landfill’s operating permit by 10 years. But the landfill’s operators and the groups suing over the environmental report have appealed the matter to the County Board of Supervisors. Sanitation Districts officials want to keep the dump open for 20 years, but opponents, most of them mostly nearby residents, want it closed this year.

Nevertheless, many officials are touting the landfill’s new gas processing facility as a significant step in the fight against air pollution.

The facility “marks the beginning of an important program . . . breakthrough technology that will significantly improve the air quality in the entire L.A. Basin,” said 4th District County Supervisor Deane Dana, whose district includes Puente Hills.