California Association of Sanitation Agencies

In an effort to get a handle on emissions of greenhouse gases (GHGs), both the US EPA and the California Air Resources Board have implemented programs that require mandatory reporting of GHGs for regulated facilities.

US EPA’s Greenhouse Gas Reporting Program requires specific industries to report. Municipal wastewater treatment is not among the industries subject to mandatory reporting under the current rule. Stationary combustion sources, including combined heat and power operations at wastewater treatment plants, do have to report if their emissions exceed 25,000 metric tons/year; however only fossil fuel-based emissions count toward this threshold – biogenic emissions, including combustion of digester and landfill gas, are excluded under EPA’s rule.

The California Air Resources Board’s GHG Mandatory Reporting Program captures a broader spectrum of industries than EPA’s. While there is no specific category for municipal wastewater treatment plant reporting, under California’s program, biogenic emissions do count toward the applicability thresholds. Therefore, several California wastewater facilities have been reporting emissions under the rule for the past several years, when the threshold for applicability was 25,000 tons/year. Cogeneration facilities were also required to report if they had a total nameplate generating capacity greater than 1 MW emitted at least 2,500 metric tons of CO2 per year from electricity.

Under revisions to the rule adopted in December 2010, the threshold has now been lowered to 10,000 tons/year, although the cogeneration category has been eliminated. This means that for 2011, wastewater facilities whose stationary combustion emissions are greater than 10,000 tons/year (regardless of the type of fuel combusted) must report their emissions to the Air Resources Board. These reports will be due in 2012.

RE: Comments on Revisions to Mandatory Greenhouse Gas Reporting Regulation

RE: Comments on ARB Mandatory Greenhouse Gas Emissions Reporting

RE: Amendments to the Regulation for Mandatory Reporting of Greenhouse Gas Emissions