In response to a federal court order, the Environmental Protection Agency (EPA) today issued final Clean Air Act standards for large and small boilers and incinerators that burn solid waste and sewage sludge. The EPA said, however, that it would reconsider the rules because “certain issues of central relevance” arose after the period of public comment.

The new standards cover more than 200,000 boilers and incinerators that emit mercury, cadmium, and particulates, but they cut the cost of implementation by about 50% (or about $1.8 billion) from a set of rules proposed in April 2010, the agency said.

Rules include those affecting major source facilities—about 13,800 U.S. boilers located at significant “sources of air pollutants.” For all new and existing natural gas- and refinery gas-fired units, the final rule establishes a work practice standard instead of numeric emission limits. Operators will be required to perform an annual tune-up for each unit. “Units combusting other gases can qualify for work practice standards by demonstrating that they burn ‘clean fuel,’ with contaminant levels similar to natural gas,” the EPA said.

For new and existing units with a heat input capacity of less than 10 million British thermal units per hour (MMBtu/hr), the final rule also establishes a work practice standard instead of numeric emission limits, though operators will be required to perform tune-ups every two years.

The final rule establishes numeric emission limits for all other existing and new boilers and process heaters located at major sources (including those that burn coal and biomass), however. Limits are established on emissions of mercury, dioxin, particulate matter, hydrogen chloride, and carbon monoxide. The rule also requires monitoring to ensure compliance with emission limits. The largest major source boilers must continuously monitor their particle emissions as a surrogate for metals such as lead and chromium.  All units larger than 10 MMBtu/hr must monitor oxygen as a measure of good combustion.

Finally, under the rule, existing major source facilities are required to conduct a one-time energy assessment to identify cost-effective energy conservation measures.

The EPA issued the proposed rules in April 2010 in response to a September 2009 court order—following a period when a federal court vacated industry-specific standards proposed during the Bush administration. Based on the prolific public input received following the April 2010 proposal, the EPA said it made “extensive revisions” to the rules. In December 2010, a federal court denied the agency’s request for additional time to review public comments, however, forcing the agency to issue final rules today—on the court-issued deadline.

The EPA said it slashed $1.5 billion for large sources of the cost of pollution control installation and maintenance—when compared to the proposed rules in April 2010—by addressing concerns and taking note of the more than 4,800 comments it received. However, it said, because the final standards significantly differ from the proposals, more public review is required.

EPA Administrator Lisa Jackson said in a “Notice of Reconsideration of Final Rules” submitted earlier this week in the Federal Register that a “reconsideration” was appropriate because certain “central” issues had not been addressed. “While we have taken final action on the rules … and believe that the final rules reflect reasonable approaches consistent with the requirements of the Clean Air act, some of the issues identified in the comments raise difficult technical issues that we believe may benefit from additional public involvement.”

Sources: POWERnews, EPA