Butler and Abouhend Awarded 2025 Scotiabank Climate Action Research Fund Grant to Decarbonize Wastewater Treatment

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Ahmed Abouhend

Caitlyn Butler, professor of Civil and Environmental Engineering and Associate Dean for Research and Graduate Affairs in the Riccio College of Engineering, and her postdoctoral researcher Ahmed Abouhend have been selected as recipients of the 2025 Scotiabank Climate Action Research Fund. This global initiative supports research that accelerates the transition to a low-carbon economy, and the funded UMass Amherst project focuses on decarbonizing municipal wastewater treatment in North America, one of the most energy-intensive public services.

The project, which was awarded CAD $100,000, integrates two complementary processes developed at UMass Amherst:

• a chemical-free solids separation process that enhances primary treatment and reduces downstream energy demand, and
• oxygenic photogranules (OPGs), dense photosynthetic microbial aggregates that eliminate the need for mechanical aeration, fix atmospheric CO₂, and convert wastewater carbon into biomass.

This is the first effort to combine these two innovations into a unified treatment approach. Together, they create a dual carbon-reduction pathway, reducing energy use while enabling biological carbon sequestration.

“This combination of technologies has the potential to transform wastewater treatment from one of the largest municipal energy consumers into a net-positive, climate-adaptive process,” said Abouhend.

Caitlyn Butler

The Butler team will design, build, and validate the integrated treatment system in collaboration with the UMass Amherst Water & Energy Technology (WET) Center. The team will assess:

• energy savings achieved by replacing aeration with OPGs,
• improvements in solids and carbon removal using the chemical-free flocculation process,
• atmospheric CO₂ fixation,
• operational reliability under real wastewater conditions, and
• techno-economic feasibility for municipal adoption.

Validation results will provide valuable insights for utilities across the U.S. and Canada seeking low-cost, low-carbon treatment solutions that can be incorporated into existing infrastructure.

If adopted widely, such an integrated system could reduce wastewater treatment costs by up to 50%, cut greenhouse gas emissions, and help eliminate chemical dependence—offering a climate-positive pathway adaptable to both high-income and resource-constrained municipalities.

The team will share their results through peer-reviewed publications, technical guidance for utilities, and collaborations with municipal, regulatory, and industry partners.