RESEARCH

OVERVIEW

Research in Dr. Aggarwal’s lab bridges environmental engineering, microbiology, and Arctic systems science, with a focus on safeguarding public and ecological health in extreme environments. His work integrates experimental and modeling approaches to address pressing challenges related to water quality, biofilm dynamics, and air quality particularly in cold regions. Dr. Aggarwal has led and contributed to several federally funded projects investigating microbial growth in drinking water systems, oil spill response in the Arctic, and particulate air pollution in rural and underserved communities. His team explores the behavior of biofilms in engineered systems, the fate and transport of pollutants, and the impacts of ultrafine particles and indoor air quality on community health. Recent research emphasizes real-time air quality monitoring, low-cost sensor deployment, and the development of strategies to mitigate air and water pollution in Alaska Native and rural communities, with a strong focus on environmental justice and infrastructure resilience. Dr. Aggarwal actively collaborates across disciplines and mentors undergraduate and graduate researchers, with the lab’s work featured in peer-reviewed journals, public outreach efforts, and broader Arctic science initiatives. A full list of publications is available on Google Scholar.

BIOFILMS IN DRINKING WATER PIPELINES

Image: Gomez-Smith and Aggarwal S. (2019). Encyclopedia of Water: Sci., Tech., & Society,1-17. 10.1002/9781119300762.wsts0193

Biofilms are routinely formed in water treatment systems (e.g., GAC filters, ultrafiltration membranes) and water distribution pipelines. In wastewater treatment biofilms are formed on trickiling filters, rotating biological contactors, and also membrane biofilm reactors. Biofilms can aid in biodegradation of contaminants as well as hinder performance (e.g. in ultrafiltration membranes) via biofouling. Traditionally, biofilm processes have not received significant attention in overall function and performance of water and wastewater systems. We are interested in investigating the role of biofilms in natural and engineered environmental systems.

MECHANICAL PROPERTIES OF BIOFILMS

Biofilms are communities of microorganisms attached to a solid surface in a self-secreted slime comprising extra-cellular polymeric substances (EPS). Biofilms are ubiquitously present on all moist surfaces of the world. To attain better biofilm control (attachment or removal from surfaces), it is important to understand the factors which control biofilm detachment -- which in turn, is dependent upon the mechanical properties of biofilms. We are interested in experimental and modeling approaches to measure biofilm mechanical properties and understand the role in biofilm process in natural and engineered systems.

Image: Micro-cantilever test platform for laboratory measurement of biofilm mechanical properties.

Relevant Publications:

Hasan and Aggarwal, 2025, Colloids and Surfaces B: Biointerfaces, 246, 114341
Kabir et al., 2024, ACS ES&T Water, 4 (5), 2088-2100
Aggarwal et al. 2010, Biotechnology & Bioengineering, 105(5), 924-934

WATER TREATMENT TECHNOLOGIES

There is a pressing need for preserving and expanding our water supplies by innovative approaches in water treatment, recycling, desalination. Recovery and recycling of used domestic, agricultural or industrial waste water for human and/or agricultural use presents challenges in terms of removal of organic contamination and several micro-pollutants to ensure food safety and public health. Thus it is required to develop innovative solutions for meeting the needs of next generation water supplies.

Image: Adsorptive Removal of Se(IV) by Citrus Peels. https://doi.org/10.1021/acsomega.0c01347

PARTICULATE MATTER IMPACTS ON AIR QUALITY

With increasing fraction of world population residing in fast-expanding urban areas of the world, ambient air quality issues are on a rise. Specifically, exposure to fine and ultrafine particulate matter (PM2.5 and PM0.1) have been correlated with adverse human health impacts. It is important to, therefore, understand the factors which impact the spatio-temporal variability of air quality parameters which can help mitigate human exposure.

Image: Modeling of ultrafine particulate matter (UFP) on Minnesota freeways. [Aggarwal et al., 2012, Environ. Sci. & Technol., 46(4): 2234-41]

ENVIRONMENTAL IMPACTS OF OIL SPILL RESPONSE

According to USGS estimates the Arctic contains vast oil and natural gas reserves, and thus witnesses considerable oil exploration especially on the North Slope of Alaska. In the wake of 2010 Deepwater Horizon incident, additional measures for emergency response and containment requirements are needed to address a possible oil release in the Arctic. Many oil spill response technologies which are applicable in warm regions need to be re-assessed and re-designed for the Arctic application. There is also increased interest in the environmental fate and transport of oil spill response chemicals and any associated environmental impacts they may cause in Alaskan -off shore waters and marine wildlife. Our specific research interests include a) environmental fate of oil spill response chemicals, and, b) air quality impacts of in-situ burning of spilled oil.

Image: Experiments for assessing environmental fate and air quality impacts of chemical herder-mediated in-situ burning at UAF fire facility.

[Bullock et al., Journal of Env. Management, 190, 266-273 ]

Image: Aerial application of herding agents to advance in-situ burning for oil spill response in the Arctic

[Aggarwal et al., Cold Region. Sci. Technol., 135, 97-104]

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