Kara L. Nelson - Students

Current PhD Students



Rabia Chaudhry 



My current research involves understanding the treatment of viruses in wastewater, specifically looking at pathogenic virus removal mechanisms in membrane bioreactor systems. My broader interests are in microbiological water quality and finding sustainable water reuse strategies within the developing and developed world context. Some previous research topics include wastewater reuse in aquaculture and safe storage of drinking water. 


John Erickson  



John researches piped drinking water systems that operate intermittently and the effect of intermittent supply on water quality and infrastructure condition. The research is intended to help water utilities prioritize infrastructure investments and operate their distribution systems more effectively.


Emily Kumpel


Emily Kumpel is a PhD candidate in Civil Systems program in Civil and Environmental Engineering. Her dissertation research focuses on understanding the effects of intermittent piped water supply on water quality available to households in urban India, and, in collaboration with students in Public Health and the Energy and Resources Group, measuring the impact of switching from intermittent to continuous water delivery. She is also involved in projects using information and communication technologies (ICTs) to improve piped water services and understanding factors leading to sustainability of small community water supplies.

Mi Nguyen 


Sunlight inactivation can potentially be used as a barrier to remove waterborne pathogens.  My research focuses on studying how sunlight damages two bacterial indicators, E. coli and Enterococcus faecalis, for the purpose of improving our understanding of sunlight inactivation mechanisms.  The interaction between dissolved organic matters with the membranes of the bacteria is currently being studied; this understanding will be applied to investigate how reactive oxygen species produced in sunlight inactivation causes damage to the bacteria, and to model the inactivation of the bacteria in a treatment wetland.  

Fermin Reygadas 


Fermin is a PhD student in the Energy and Resources Group.  His research and practice interests lie at the intersection of WASH (water, sanitation, and hygiene); public health; human centered design; contextualized innovation; sustainable development; and social entrepreneurship.  As part of his dissertation research, Fermin designed a household system (Mesita Azul) that uses ultraviolet light to disinfect water.  Fermin co-founded Fundacion Cantaro Azul a non-profit organization that designs and implements safe water, hygiene, and sanitation programs in underserved communities. Most recently, Fermin has led the development of Nuestra Agua, a collaborative project between UC Berkeley and Cantaro Azul that has designed safe water solutions for schools, health clinics, and communities. 

Andrea Silverman


Andrea's research interests include waterborne pathogens, natural mechanisms of disinfection, wastewater reuse, and low-cost wastewater/fecal sludge treatment to mitigate the microbial health risks associated with waste reuse. Andrea studies sunlight disinfection of viruses in the laboratory and, in the field, its application as a low-cost intervention to treat wastewater used in urban, irrigated agriculture in Ghana. 

Anne Thebo


Anne Thebo is a PhD student in environmental engineering whose research focuses on understanding the impacts of wastewater irrigation in developing countries. She is conducting a spatially based assessment of wastewater irrigation at the global scale and a case study in Hubli-Dharwad, India evaluating the relationship between irrigation practices, health, and upstream sanitation infrastructure. Her work seeks to both quantify the extent of irrigation with untreated wastewater and better understand the factors which either exacerbate or mitigate risks associated with this practice.

Andrew Torkelson


My research focuses on the filtration of waterborne pathogens from drinking water and stormwater.  In drinking water, I am researching new types of media that can readily remove bacteria and viruses in point-of-use (POU) filters in developing countries.  In stormwater, I am conducting research as part of the NSF funded engineering research center on urban water infrastructure, ReNUWIt.  My research is focused on improving media used in green infrastructure and low impact developments for removing pathogens from urban runoff.  I'm particularly interested in the fate of attached pathogens and the long-term potential of geomedia.

Current Postdoctoral Researchers


Jannis Wenk


Jannis received his BSc and MSc in Environmental Engineering from TU Berlin/Germany. During his PhD-studies at ETH Zurich and at Eawag/Switzerland he investigated the role of dissolved natural organic matter (DOM) in natural and technical systems. His areas of expertise are environmental photochemistry, reaction mechanisms in aquatic oxidation processes and transformation pathways of contaminants in the environment and in water treatment.  Jannis is a joint postdoc with David Sedlak’s  group. His current research is studying light-induced virus inactivation with various photosensitizers. This investigation aims to better understand pathogenic virus removal mechanisms in the environment and constructed water treatment wetlands. Furthermore, he is also involved in projects on the photochemical fate of antiviral compounds in treatment wetlands and on the applicability of advanced oxidation processes for contaminant removal in decentralized wastewater treatment facilities. 


Current Undergraduate Researchers

  • Katya Cherukumilli
  • Fikreselam Habebo
  • Malavika Neti

Former Lab Members

Temitope Ogunyoku, former postdoc.


Temitope Ogunyoku is currently at IBM Research-Africa in Nairobi, Kenya.


Postdoctoral researchers (current position): Jee Yeon Kim (2009-2010; Samsung Research Group); David Love (2007-2009; Johns Hopkins University); Allegra da Silva (2008-2009; CDM); Maria Raynal (2007-2008 ; Universidad National Autonoma de México); Tamar Kohn (2004-2006; école Polytéchnique Fédérale de Lausanne); Jose Antonio Barrios (2005; National Water Commission, México)

Ph.D. students: Sintana Vergara (May 2012; World Bank); Michael Fisher (July 2011; Microvi Technologies); Khalid Kadir (July 2010; lecturer, U.C. Berkeley); Ashley Murray (May 2009; Founder, Waste Enterprisers, Accra, Ghana); Gordon Williams (May 2009; Trussell Technologies); Sarah Silkie (August 2008); Brian Pecson (Fall 2006; Trussell Technologies); Tryg Lundquist (Fall 2006; Associate Professor, Cal State San Luis Obispo)

M.S. students: Deepak Subramanian, Alejandro Guido, Jeff Dahm, Forest Kaser, Micah Lang, Fermin Reygadas, Sarah Brownell, Hans Schwing, Amy Pickering, Alicia Chakrabati, IlJoo Yang, Matthew Tolcher 

B.S. students: Fikreselam Habebo, Katya Cherukumilli, Malavika Neti, Douglas Fabini, Joshua Song, Majid Khan, Brian Coox, Ofelia Romero, Rachel Peletz, April Wong, Sonia Lopez, Ali Kattan, Senem Surelli