On February 23, EPA promulgated pre-publication Federal Register new source performance standards and emission guidelines for sewage sludge incineration units (SSIs) located at wastewater treatment facilities designed to treat domestic sewage sludge. EPA also finalized rulemaking for the definition of solid waste. The SSI pre-publication final rule (496 pages) sets limits for nine pollutants under Section 129 of the Clean Air Act (CAA) – maximum achievable control technology (MACT) standards for: cadmium, carbon monoxide, hydrogen chloride, lead, mercury, nitrogen oxides, particulate matter, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, and sulfur dioxide. The SSI final rule is effective 60 days after the date of publication in the Federal Register. According to an EPA press release, while there are more than 200 SSIs across the country, the Agency expects that over 150 are already in compliance. EPA also stated that these standards will reduce emissions of harmful pollutants including mercury, lead, cadmium, and hydrogen chloride from the remaining 50 that may need to leverage existing technologies to meet the new standards. EPA SSI web page. A quick review indicates:
- There were no changes made regarding statutory arguments made by several entities during the proposed rulemakings - the rule remains under Section 129 of the Clean Air Act
- The standards are still divided into two subcategories, for multiple hearth and fluidized bed.
- The beyond the floor level of control for mercury has been dropped from the final rule.
- Some adjustments to the other emission limits have been made to make them more consistent with existing 503 regulations.
- EPA will not be voluntarily reconsidering the final rule. While EPA will reconsider the other rules being finalized (boiler rulemaking), EPA has decided that it does not need to reconsider the final SSI MACT Rule but has the authority under the CAA to do so. However, petitioners have 60 days following publication in the Federal Register to request reconsideration and reopen the rule for further comment.
EPA also identified which non-hazardous secondary materials are considered solid waste when burned in combustion units in the definition of solid waste rulemaking. This distinction determines which Clean Air Act standard is applied when the material is burned. The non-hazardous secondary materials that can be burned as non-waste fuel include scrap tires managed under established tire collection programs. This step simplifies the rules and provides additional clarity and direction for facilities. To determine that materials are non-hazardous secondary materials when burned under this rule, materials must not have been discarded and must be legitimately used as a fuel. EPA determined that biosolids were considered as material that is discarded in SSIs, and thus a solid waste, prompting the Section 129 CAA rulemaking.
The National Biosolids Partnership, in conjunction with WEF, plans to hold a no charge webcast on April 27 to discuss details of the SSI rulemaking and issues associated with implementation. More information on the webcast will be provided shortly.