SMART-Plant_GHG and energy consumption: the overlooked challenges in wastewater treatment

Sustainable water management systems are in the heart of low-carbon and energy resilient economies. However, wastewater treatment plants (WWTPs) are vigorous energy consumers. For many European municipalities, they are the largest energy consumers with a share of 20% of the municipality’s electrical load. On top of that, wastewater treatment facilities also emit greenhouse gases (GHGs). The direct GHG emissions, mainly connected to the treatment process, include methane (CH4) and nitrous oxide (N2O). Indirect emissions occur due to the use of energy. With a global warming potential (GWP100) of 265 times higher than that of carbon dioxide (CO2), N2O is a potent GHG and the most significant contributor to ozone depletion. 1 WWTPs are responsible for 6% of the global anthropogenic N2O emissions. 2 In the sewer system conveying wastewater to the treatment plants anaerobic conditions prevail, resulting in the emission of CH4 (GWP100 CH4 = 28)