New SWANA report shows WTE has cleaned up

The Solid Waste Association of North America’s (SWANA) Applied Research Foundation (ARF) has released a new report, Advanced Air Pollution Control at Waste-to-Energy Facilities.

This report reviews commercially proven, new and emerging nitrogen oxide (NO_X) and carbon dioxide (CO₂) control technologies that can potentially be deployed in existing WTE facilities.

As discussed in the report, WTE emissions have significantly declined over the last 30 years with seven of the nine regulated pollutants reduced by an average of 95% due to the investment of over US$1 billion in air pollution control systems.

Despite these accomplishments, WTE facilities are often targeted by environmental groups to further reduce their emissions since they are often among the largest point source of NO_X and CO₂ emissions in a community, even though the largest source by far of these emissions is generally the transportation sector.

The report offers case studies that present three different approaches that can be considered by WTE plant managers interested in evaluating NOX technology reduction options for their facilities. It looks at options for new and retrofitted systems, using Selective-Non-Catalytic-Reduction (SNCR) technology (including Advanced SNCR) and Selective-Catalytic-Reduction (SCR) technology. The major difference between these technologies is that one utilizes a catalyst to accelerate the reaction of ammonia with NOX to produce nitrogen and water vapor.

According to the report, most WTE facilities in the US have been equipped with the SNCR technology to comply with the regulatory requirements regarding NOX emissions. In the SNCR process, nitrogen oxides (NO + NO2) are removed by injecting a reducing agent (typically ammonia or urea) into the furnace. SNCR can achieve nitrogen oxides emissions reduction in the 60–80% range. ASNCR is an effective NOX reduction technology capably of achieving a 70%reduction.

It is SWANA’s hope that this report will serve as a valuable and timely reference document for WTE facility managers as they consider the benefits and costs of investing in additional NO_X control technologies and CO₂ capture systems to further reduce emissions from their facilities. The report also serves as a useful resource for state and local governmental officials evaluating WTE facilities.