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. 

Rather than building more such infrastructure in the future, the researchers found that implementing nature-based mitigation efforts across watersheds could yield astronomical savings.

Integrating solutions like wetland construction or reforestation has the potential to save more than 4.2 million tons of carbon dioxide equivalent emissions each year, according to the study, published Monday in Nature’s “Communications Earth & Environment” publication.

“These findings draw a line in the sand that shows what the potential for adopting green approaches in this space is — both in terms of money saved and total emissions reduced,” first author Braden Limb, a PhD student at Colorado State University’s Department of Systems Engineering, said in a statement. 

The optimal rollout of such methods, the researchers found, would involve support via carbon financing — in which companies offset their emissions by voluntarily buying “credits” on an open market that represents emission reductions.

Carbon markets could be leveraged to alter some of the monetary incentives that farmers receive when it comes to water treatment and their environmental impact, the authors explained.

The availability of private capital, they found, could motivate utilities and regulators to take proactive measures — redirecting that capital toward water infrastructure and thereby move away from fossil-fuel reliant facilities. 

After conducting a cost-benefit analysis in which the authors looked at data from more than 22,000 current wastewater treatment facilities, they determined the use of carbon markets could generate $679 million in annual revenue to finance such a transition.

Co-author Jason Quinn, a Colorado State University mechanical engineering professor, acknowledged the study’s limitations — particularly noting the local aspect of water supplies and quality issues and the global nature of carbon.

This discrepancy, he and his colleagues explained, has reduced the value of water market trades in the past.

“But by bringing these market mechanisms together,” Quinn continued, “we can capitalize on a window of opportunity to accelerate the improvement of America’s rivers as we transition to a renewable energy and restored watershed future.”