Caitlyn Butler
University of Massachusetts, MA·Engineering
Treated wastewater still carries nitrogen and phosphorus, and when those nutrients reach rivers, lakes and estuaries they feed algal blooms and degrade water quality. Conventional treatment steps such as activated sludge, aerated lagoons and membrane bioreactors often cannot meet increasingly strict discharge limits, and the advanced options that can, like chemical precipitation or enclosed photobioreactors, are expensive and energy-hungry.
- Fields
Engineering
Earth & Environmental Science
Microbiology & Immunology
- Topics
oxygenic photogranules
wastewater treatment
nutrient removal
- Grants
- 1 known grant, through Jul 2028
What they work on
- Demonstrate that oxygenic photogranules, dense clusters of algae, cyanobacteria and bacteria, stay intact and grow stably in nutrient-poor secondary effluent by measuring granule formation, size distribution, density, porosity and shear resistance.
- Assess microbial physiological responses to low-nutrient stress using extracellular polymeric substance profiling, enzyme activity assays, and RT-qPCR of genes for ammonia oxidation, denitrification and phosphorus uptake.
- Optimize sequencing batch reactor operation, including light intensity, mixing pattern, hydraulic retention time, solids retention time and shear stress, to maximize nitrogen and phosphorus removal rates.
- Deliver a scalable, low-energy post-secondary treatment process and a mechanistic account of how photogranules remove nutrients when nitrogen and phosphorus are limited.
More about the research
This project tests a low-energy alternative built on oxygenic photogranules (OPGs): dense, self-assembling clusters of cyanobacteria, algae and other bacteria that use sunlight to pull nutrients out of water. Because the granules are compact, they settle on their own, so no mechanical or chemical separation step is needed, and they can run in simple tanks with modest light and mixing.
Why it matters
Nutrient pollution from municipal wastewater drives eutrophication and harmful algal blooms in U.S. surface waters, yet the advanced treatment needed to meet strict discharge limits is costly for towns to build and run. A photogranule system that settles on its own and needs little energy, light or chemical addition could lower treatment costs for communities and household water bills while protecting sensitive watersheds.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Ian Bradley
University at Buffalo, NY·Engineering·Early-career
Identify the environmental and operating factors that improve total nitrogen and phosphorus removal in algae-based wastewater treatment, using lab-scale systems that grow algae on wastewater.
James Moberly
University of Idaho, ID·Engineering
Develop an encapsulated biological material in which phosphorus accumulating organisms, microbes that store large amounts of phosphorus, are immobilized within a polymer structure for use in wastewater treatment.
Sarah Preheim
Johns Hopkins University, MD·Earth & Environmental Science
Test how the abundance of denitrification genes, measured by quantitative PCR, relates to denitrification rates in controlled bioreactor experiments, and whether disturbance frequency changes that relationship.
The school
University of Massachusetts: 28 labs on PI Pages, $282M a year on research, 337 research doctorates a year.
Reach out
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