EPA announced in the October 14 Federal Register proposed rulemaking to cut emissions of mercury, particle pollution and other harmful pollutants from sewage sludge incinerators (SSIs). According to EPA, SSIs represent the sixth-largest source of mercury air emissions in the U.S. The proposed standards would apply to both multiple-hearth and fluidized bed incinerators. Units incinerating sewage sludge at other types of facilities such as commercial, industrial and institutional incinerators will be covered under different air pollution standards. Overall, the proposal is intended to cut mercury emissions from these units by more than 75 percent. EPA estimates that the proposal would yield health benefits ranging from $130M to $320M in 2015, with annualized costs estimated at approximately $105M for all currently operating units to comply with the proposal standards.
The proposed rule would set numeric emissions limits for both new and existing sewage sludge incinerators with separate standards for multiple hearth and fluidized bed incinerators. For existing multiple hearth incinerators, EPA is proposing a cadmium emissions limit of 0.095 milligrams per dry standard cubic meter (mg/dscm). The proposed limit for mercury would be 0.02 mg/dscm. For lead, the proposed emissions limit would be 0.30 mg/dscm. The proposed particulate matter standard would be 80 mg/dscm. For carbon monoxide, the proposed emissions limit would be 3,900 parts per million of dry volume (ppmvd). The proposed standards for hydrogen chloride would be 1.0 ppmvd. The emissions limit for nitrogen oxides would be 210 ppmvd. For sulfur dioxide, the proposed emissions limit would be 26 ppmvd. EPA proposed two emissions limits for dioxins and furans, one based on toxic equivalency and the other on a total mass basis. The proposed toxic equivalency standard would be 0.32 nanograms per dry standard cubic meter (ng/dscm) while the total mass standard would be 5.0 ng/dscm. Existing multiple hearth sewage sludge incinerators would have an opacity limit of 10 percent.
For existing fluidized bed incinerators, EPA is proposing a cadmium emissions standard of 0.0019 mg/dscm. For mercury the emissions standard would be 0.0033 mg/dscm. The proposed lead emissions limit would be 0.0098 mg/dscm. The proposed particulate matter emissions standard would be 12 mg/dscm. For carbon monoxide, the proposed performance standard would be 56 ppmvd. The emissions limit proposed for hydrogen chloride would be 0.49 ppmvd. EPA proposed an emissions limit of 63 ppmvd for nitrogen oxides and 22 ppmvd for sulfur dioxide. For dioxins and furans, EPA proposed an emissions limit of 0.056 ng/dscm based on toxic equivalency or 0.61 ng/dscm on a total mass basis. Existing fluidized bed incinerators would have a proposed opacity limit of 0 percent. EPA proposed identical emissions limits for new multiple hearth and fluidized bed sewage sludge incinerators.
The proposed rules would establish opacity limits and emission limits for nine pollutants emitted from the regulated SSI units: mercury, lead, cadmium, hydrogen chloride, particulate matter, carbon monoxide, dioxins/furans, nitrogen oxides, and sulfur dioxide. The proposed standards may require approximately 196 of 218 SSI units to install one or more air pollution control devices including: activated carbon injection, fabric filters, or high efficiency scrubbers. The proposal also requires provisions for testing, monitoring, recordkeeping, reporting and operator training. The Clean Air Act (CAA) requires EPA to develop and adopt new source performance standards (NSPS) and effluent guidelines (EG) for solid waste incineration units including SSI under Section 129 of the CAA. EPA has never regulated SSI units under section 129 of the CAA. EPA will take comment on the proposed rule until November 15. The rule will be finalized in 2011 and become effective in 2015. WEF plans to submit comments on the SSI proposed rulemaking.