The EPA has promulgated emission limits for sewage sludge incinerator (SSI) units at wastewater treatment facilities, including emission limits for both existing and new sewage sludge incinerator units (40 CFR Part 60 Subparts MMMM and LLLL, respectively). Emissions are limited under these rules for nine air pollutants: cadmium, carbon monoxide, hydrogen chloride, lead, mercury, nitrogen oxides (NOx), particulate matter (PM), dioxins & furans, and sulfur dioxide (SO2). Many existing sewage sludge incinerator units do not meet these new emission limits for mercury, and some units additionally require controls for one or more other contaminants besides mercury, such as dioxins & furans or SO2. New sewage sludge incinerator units are unlikely to be able to meet the new emission limits for mercury without mercury control equipment. APC provides equipment to meet the emissions limits for both the Subpart MMMM emission limits and the stricter Subpart LLLL limits.
APC has performed multiple successful emission control projects to control mercury and other emissions from sewage sludge incinerator units. EPA compliance test results for mercury emissions where APC’s MercPure Mercury Emission Control Systems have been installed have consistently been multiple orders of magnitude below the Subpart MMMM and LLLL limits for mercury. In addition to easily passing the mercury emission requirements, APC’s MercPure systems can also be designed to achieve compliance with particulate matter (PM), cadmium, lead, dioxins and furans, and SO2 emission limits as required.
A major challenge when treating sewage sludge incinerator exhaust gases is to properly treat and condition the gas stream, which typically contains a significant level of very fine particulate, including very fine mist droplets at some locations, and also has a high dew point. In addition, condensation generated during treatment of these gases can damage equipment and cause operational and performance problems if both the gas stream and the equipment are not conditioned properly first. APC is very familiar with these issues that are specific to sewage sludge incinerator emissions, and APC designs its MercPure Emission Control Systems to integrate all of the equipment needed to address these issues, including: mist eliminators, filtration equipment, adsorption equipment and media, gas heaters, blowers, instrumentation, valves/dampers, and controls. APC is adsorption-media independent and selects the best media available on the market for the application considering cost, performance and bed longevity. For additional detail on these systems, click on MercPure Mercury Emission Control Systems .
Because of APC’s robust sewage sludge incinerator system designs that include multiple stages of gas treatment, including APC’s exclusive Ultra-High-Efficiency Filter (UHF®), these systems not only control mercury emissions to far below the required emission standards, but can also simultaneously reduce emissions of particulate matter (PM), cadmium, lead, other metals, dioxins and furans, ensuring compliance with the new regulatory limits for these contaminants as well. APC’s systems are further designed to minimize maintenance and life-cycle costs.