"Wastewater treatment plants may be responsible for emitting up to 23 percent more greenhouse gas than previously thought because of fossil fuels in detergent-laden water from residential showers, household washing machines and industrial sites, new research shows.
Treatment plants emit greenhouse gases such as methane and nitrous oxide when they purify drain water containing detergents and personal care products derived from petroleum. International tallies of greenhouse gas emissions are underestimating the plants’ effect on the climate, however, because they do not account for carbon dioxide emissions when that water is processed, according to a study published Wednesday in the journal Environmental Science and Technology.
Wastewater treatment plants are responsible for an estimated 3 percent of greenhouse gas emissions globally. Countries will need to consider many different ways to cut emissions in order to meet their obligations under the Paris Climate Agreement and prevent global warming from exceeding 2°C (3.6°F). The study suggests that wastewater treatment plants hold one key to those greenhouse gas reductions."