While the solid waste and recycling industry is using thousands of new trucks that run on alternative fuels, most of the garbage and recycling trucks operating in the United States are still diesel powered. But truck manufacturers are making improvements there as well.
Ultra-low sulfur diesel (ULSD) fuel was adopted by the Environmental Protection Agency as a new standard for the sulfur content in on-road diesel fuel. The allowable sulfur content for ULSD (15 ppm) is much lower than the previous U.S. on-road standard for low sulfur diesel (500 ppm), which not only reduces emissions of sulfur compounds (a cause of acid rain), but also allows advanced air pollution control systems to be fitted that would otherwise be ruined by these compounds. These systems greatly reduce emissions of nitrogen oxides and particulate matter. EPA estimates that the implementation of the new fuel standards for diesel will reduce nitrogen oxide emissions by 2.6 million tons each year and particulate matter by 110,000 tons a year.
Some local governments are mandating additional changes to achieve even greater emission reductions. For example, diesel garbage trucks in Seattle and San Francisco are using a blend of ULSD and biodiesel, usually derived from vegetable oil. With such a blend, emissions of fine particulates and toxic air pollutants can be reduced by as much as 90 percent compared to traditional diesel fuels.
Manufacturers of garbage truck engines also continue to improve diesel engine technology. The adoption of some of these advancements has been mandated by EPA regulations. New diesel engines now produce less than 10 percent of the emissions of 2001 models. These emission reductions were achieved using various advanced technologies by different companies, including selective catalytic reduction, advanced exhaust gas recirculation, modified turbocharger rates, optimized combustion, and the careful calibration of electronic engine controls.