Waste-to-energy emissions: How low can they go?

New and existing waste-to-energy (WTE) facilities continue to demonstrate that they are environmentally friendly, have advanced emissions control, continuous emission monitoring systems (CEMs) and reporting systems, and continue to improve their practices to reduce the amount of emissions they emit.

Over the past decade, WTE facilities have adopted new technologies and practices for ensuring compliance with regulations, and in addition to reporting their emission to permitting agencies, they are also reporting it to the general public. New conversion technologies are challenging regulators, but they promise to produce lower emissions than mass-burn facilities.

A table, which can be accessed at www.REWmag.com/rew0214/emission-limits-table.aspx, shows the average emissions from three mass-burn WTE facilities across the country; permit limits for the new Palm Beach County, Fla., mass-burn facility (currently under construction); permit limits for the city of Los Angeles Green Conversion Systems (GCS) thermal recycling facility (which has been awarded a permit); and permit limits from Ineos Bio’s Vero Beach, Fla., gasification facility, as compared to the U.S. Environmental Protection Agency’s (EPA’s) proposed new Maximum Achievable Control Technology (MACT) standards (the maximum achievable emission reduction when modern emissions control technologies are applied). Although these permit limits provide limits on pollutant concentration, these facilities have a range of exhaust gas flow rates, and some gasification technologies estimate that they will produce as low as 35 percent of the gas flows of a mass-burn WTE facility.

Not only do these existing mass-burn facilities operate at close to current MACT levels, both of the new facilities are permitted at far below MACT levels in many categories, and actual operating performances can be expected to be even lower than permit limits. Facilities in the U.S. employ CEMs, and some (including Montgomery, Md., and Onondaga County, N.Y.) publish their continuous testing results on their websites.

It is necessary to have room under your permit to allow for emission spikes that will occur occasionally during periods of upset combustion (usually due to rain), startup and shutdowns. As permit limits continue to be lowered, they need to recognize that facilities will not always be operating under ideal conditions, especially when there are extended deliveries of wet waste.

New alternative conversion technology facilities under development will need to be permitted as they advance in development, and regulatory agencies will be faced with determining how these technologies are permitted. Ineos Bio in Vero Beach was granted air permits by the Florida Department of Environmental Protection. The Ineos facility is currently using only wood waste and its performance gasifying MSW has not yet been determined.

In California, regulators have been considering how to permit conversion technology emissions for more than five years now, as projects started in Santa Barbara, Los Angeles and other communities progress.

Currently, GBB has identified some dozen projects implementing conversion technologies that are at different levels of development in the U.S. Studies performed on behalf of these communities determined that “thermochemical conversion technologies are able to meet existing local, state, federal and international emissions regulations” and “worldwide analysis shows gasification and pyrolysis facilities currently in operation meet each of their respective air quality emission mandates required by the U.S. EPA, the European Union and Japan.” In addition, many contend that conversion technologies have lower air emissions compared with mass-burn WTE, including lower emissions of methane, carbon dioxide (CO₂), and other greenhouse gas emissions as well as lower emissions of criteria air pollutants such as nitrogen oxide (NOx) and sodium oxide (SOx). Mass-burn and refuse-derived fuel waste-to-energy facilities have been successful at reducing emissions, monitoring their operations and meeting environmental regulations. As Ineos Bio and others come online, we will find out if they can do better!

Research assistance provided by Elizabeth Rice and Ljupka Arsova, consultant IIs, GBB.

Harvey Gershman, hgershman@gbbinc.com, is president of Gershman, Brickner & Bratton Inc., solid waste management consultants.