https://thehill.com/policy/energy-environment/4597794-switching-to-greener-wastewater-treatment-could-save-billions-study/

Switching to greener wastewater treatment approaches could slash carbon emissions and save the country $15.6 billion, a new study has found.

Traditional point-source sewage treatment facilities — which eliminate pollutants like nitrogen and phosphorous before releasing water back into the system — consume 2 percent of all energy used in the U.S. and produce 35 million metric tons of carbon dioxide each year, the study authors noted.