MCLI Model Law – Methane from Wastewater Treatment Facilities (WWTF)

Methane (CH4) is a potent greenhouse gas that is the second biggest contributor to climate change after carbon dioxide (CO2). One ton of CH4 emissions has the same global warming potential (GWP) as approximately 27-30 tons of CO2, when measured on a 100-year time horizon (GWP-100), and as approximately 81-83 tons of CO2 when measured on a 20-year time horizon (GWP-20). The anaerobic digestion process at waste water treatment facilities (WWTF) typically results in a byproduct known as biogas, which contains both CH4 and CO2. Many WWTFs either vent or flare biogas, releasing greenhouse gases into the atmosphere and not utilizing a potential resource.

The Biogas Use, Reduction, and Repurposing Model Law for Wastewater Treatment Facilities requires WWTFs with a wastewater flow rate of 5 million gallons per day or more, referred to as Large WWTFs, to cut almost all methane emissions and harness biogas as an energy source. WWTFs can shift away from venting or flaring biogas and instead install or upgrade combined heat and power (CHP) systems to convert the biogas into electricity, fuel, and thermal energy. This can provide multiple benefits, including cost savings for the owner or operator of the WWTF, which is often a municipal entity, increased resilience for the facility, and reduced emissions. The legislation would also provide a tax credit for to help further incentivize the sale of biogas from Large WWTFs.