The Impacts of the California Global Warming Solutions Act of 2006 (AB 32) on POTWs

In 2006 the California legislature established, and the Governor signed, the California Global Warming Solutions Act of 2006 (Assembly Bill 32, AB 32). AB 32 mandates that the California Air Resources Board (CARB) adopt rules and regulations to reduce greenhouse gas (GHG) emissions to 1990 levels by the year 2020. In order to meet this goal CARB must adopt regulations on mandatory emission reporting and verification and emissions reduction measures. CARB may further adopt regulation on market-based compliance mechanisms, such as a cap-and-trade program.Based on CARB's initial regulatory concepts, the largest emitters of GHG emissions will be required to report emissions first. While the publicly owned treatment work (POTW) sector is not identified as one of the largest GHG emissions sources, they may still need to meet the requirements of other identified sectors (i.e., Power/Utility and Large Stationary Combustion), such as their requirement are applicable to POTW operations. The California Wastewater Climate Change Group (CWCCG) anticipates that once CARB regulates the largest sources of emissions, they will create regulations for the next largest sources of emissions, which may include POTWs. In a proactive approach to emissions reporting, the CWCCG has begun to develop protocols to estimate methane (CH4) and nitrous oxide (N2O) emissions from wastewater treatment plant (WWTP) processes.While CARB is still in the process of developing regulations to meet the state's 2020 emissions goal, POTWs can take a proactive approach to meeting future GHG emissions regulations by first conducting a GHG inventory. POTWs should then look into developing and implementing GHG reduction strategies and should record their emissions reductions to seek credit in the future as regulations are developed.