California Association of Sanitation Agencies
On May 13, 2010, US EPA published its final Tailoring Rule. This rule lays out Prevention of Significant Deterioration (PSD) and Title V Major Source permitting requirements for greenhouse gases (GHGs) under the Federal Clean Air Act. It is called the Tailoring Rule because it “tailors” the thresholds from the usual 100 or 250 tons/year thresholds used in the Clean Air Act for criteria pollutants to higher thresholds that are more implementable for GHGs.
Though the rule does not distinguish between anthropogenic emissions (e.g. GHGs from fossil fuel combustion) and biogenic emissions (e.g. GHGs from combustion of biomass fuels such as landfill or digester gas), on July 1, 2011, EPA issued a rule deferring the permitting requirements for biogenic sources of CO2 including wastewater treatment plants and combustion of biogas for a period of three years. During that three year period, EPA, with the help of a panel of experts serving on a Scientific Advisory Board, will continue to study the issue of how best to address biogenic emissions under the Clean Air Act.
This new rule is a very positive development for the wastewater community and is consistent with comments that CASA and the California Wastewater Climate Change Group (CWCCG) submitted in response to the original Tailoring Rule as well as to a Call for Information issued by EPA. As a result of the deferral rule, it is expected that no new wastewater plants will be pulled into the PSD or Title V programs as a result of their GHG emissions, at least for the next three years.