Srijan Aggarwal, Ph. D.

Assistant Professor of Civil and Environmental Engineering,  University of Alaska Fairbanks  
Bacterial Biofilms in Drinking Water Distribution Systems: Problems and Solution Approaches

Abstract

Biofilms are communities of microorganisms attached to a solid surface and enmeshed in a self-secreted slime comprising extracellular polymeric substances (EPS). Biofilms occur on nearly all wetted surfaces of the world including pipe walls throughout the drinking water distribution system (DWDS) accounting for the bulk (>95%) of bacteria in these systems. The presence of microbial biofilms in the DWDS is a potential source of problems such as pathogen protection (from residual disinfection), microbially-influenced-corrosion, taste and odor issues, and increased frictional resistance. Bacteria in the biofilms are highly resistant to common antibacterial treatments, the exact cause for which is not fully understood even though several physiological explanations have been offered to explain the recalcitrant nature of bacterial biofilms. Biofilm EPS matrix, which defines the structure and strength of the biofilm is an important determinant of several biofilm characteristics, including the biofilm mechanical properties. The mechanical properties are a key to understanding removal (or detachment) of biofilms from surfaces. In this seminar, results from our experimental work investigating biofilm weakening, detachment and biofilm mechanical properties are presented in the context of DWDS. Additionally, results from a long-term (30-month) bench-scale drinking water biofilm growth study are also presented – which aim to investigate the impact of DWDS parameters (e.g., chlorination, surface material) on proliferation of biofilms within the DWDS.

Bio

Dr. Srijan Aggarwal is an Assistant Professor in the Civil and Environmental Engineering department at the University of Alaska Fairbanks since 2013. Dr. Aggarwal completed his bachelors in Civil Engineering from IIT Delhi, India (2007) and his doctoral and postdoctoral work in environmental engineering from the University of Minnesota -Twin Cities. Dr. Aggarwal’s general research interests are in the area of developing sustainable water and wastewater treatment processes with a specific focus on biofilm formation and control in natural and engineered systems. His prior research has been specifically related to biofilm mechanics and biofilm processes in the context of drinking water/wastewater treatment systems. His research has been published in reputed journals like Environmental Science & Technology, Langmuir, Biotechnology and Bioengineering; and his thesis won the Best Doctoral Dissertation award at University of Minnesota. Additionally, ASCE recognized him as an outstanding reviewer for the Journal of Environmental Engineering in 2014 and he was recognized as an ExCEEd fellow by ASCE in 2016.