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).