Andrea Silverman

Assistant Professor of Environmental Public Health Sciences

Professional overview

The goal of Dr. Andrea Silverman’s work is to develop sustainable and appropriate wastewater treatment systems, in an effort to protect public health and the environment. Within the topics of water quality and wastewater treatment, she focuses on the detection and control of waterborne pathogens, the design of disinfection processes in natural wastewater treatment systems (e.g. treatment ponds and constructed wetlands), and the safe reuse of human waste.

Dr. Silverman has conducted research in Accra, Ghana on the use of untreated wastewater for vegetable irrigation. In Nairobi, Kenya, she worked with Sanergy, a social enterprise that composts human waste for reuse in agriculture, to ensure effective quality control and safety of the end product. Her ongoing research includes the study of how sunlight kills microorganisms in water (i.e., sunlight disinfection) and the use of this information to create numerical models that predict disinfection rates, which can then be used for the design of natural wastewater treatment systems.

As a professor, Dr. Silverman teaches courses at the Tandon School of Engineering and the School of Global Public Health that address environmental contaminants and appropriate interventions reduce their public health impact, including removal and transformation processes in natural and engineered systems. Courses taught include Introduction to Environmental Engineering, Environmental Health in a Global World, and the Detection and Control of Waterborne Pathogens.

Education

BS, Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA

MS, Environmental Engineering, University of California Berkeley, Berkeley, CA

PhD, Environmental Engineering, University of California Berkeley, Berkeley, CA

Honors and awards

Outstanding Graduate Student Instructor Award, UC Berkeley (2011)

Chang-Lin Tien Fellowship, UC Berkeley (2011)

Science and Engineering for Global Health Fellowship, The Center for Emerging and Neglected Diseases, UC Berkeley (2009)

Chancellor’s Fellowship, UC Berkeley (2007)

Areas of research and study

Environmental Interventions

Environmental Public Health Services

Sanitation systems

Sustainability

Waterborne pathogens

Publications

Publications

Assessment of Commonly Measured Wastewater Parameters to Estimate Sewershed Populations for Use in Wastewater-Based Epidemiology: Insights into Population Dynamics in New York City during the COVID-19 Pandemic

Effect of pH on endogenous sunlight inactivation rates of laboratory strain and wastewater sourced E. coli and enterococci

Interlaboratory performance and quantitative PCR data acceptance metrics for NIST SRM® 2917

Making waves: Uses of real-time, hyperlocal flood sensor data for emergency management, resiliency planning, and flood impact mitigation

Monitoring SARS-CoV-2 in wastewater during New York City's second wave of COVID-19: sewershed-level trends and relationships to publicly available clinical testing data

Escherichia coli and Enterococcus spp. Indigenous to Wastewater Have Slower Free Chlorine Disinfection Rates than Their Laboratory-Cultured Counterparts

SARS-CoV-2 wastewater surveillance for public health action

Scaling of SARS-CoV-2 RNA in settled solids from multiple wastewater treatment plants to compare incidence rates of laboratory-confirmed COVID-19 in their sewersheds

Sunlight Photolysis of Extracellular and Intracellular Antibiotic Resistance Genes tetA and sul2 in Photosensitizer-Free Water

Systematic Review and Meta-Analysis of the Persistence of Enveloped Viruses in Environmental Waters and Wastewater in the Absence of Disinfectants

Systematic review of the relative concentrations of noroviruses and fecal indicator bacteria in wastewater: considerations for use in quantitative microbial risk assessment

Global Sensitivity Analysis of Environmental, Water Quality, Photoreactivity, and Engineering Design Parameters in Sunlight Inactivation of Viruses

Photocatalytic hydrogels for removal of organic contaminants from aqueous solution in continuous flow reactors

Katzenberg, A., Raman, A., Schnabel, N. L., Quispe, A. L., Silverman, A. I., & Modestino, M. A. (n.d.).

Publication year

2020

Journal title

Reaction Chemistry and Engineering

Volume

5

Issue

2

Page(s)

377-386

10.1039/c9re00456d

Abstract

Abstract

Light-driven degradation of organic contaminants by photocatalytic nanoparticles has attracted significant attention for wastewater treatment applications. However, implementation of these approaches has been limited by challenges in reactor design, which often require post-treatment separation of nanoparticles or exhibit low reactivity owing to immobilization of particles at the surface of heterogeneous supports. In this work, we present a material design strategy that circumvents these challenges by encapsulating photocatalytic particles in three-dimensional polymer networks, leading to structurally-stable photocatalytic hydrogels that were used as the walls of a flow reactor. This design leverages the volumetric reactions of commonly-implemented slurry reactors but circumvents the need for downstream separation of photocatalytic particles. A two-step soft lithography technique was used to fabricate a patterned poly(hydroxyethyl methacrylate-co-acrylic acid) hydrogel composite with embedded titanium dioxide (TiO2) nanoparticles that were employed as a photocatalyst. In this configuration, contaminant molecules introduced via a flow channel were absorbed into the hydrogel, and subsequently diffused to the surface of the embedded photocatalyst particles where they were oxidized upon light irradiation. Using reactor configurations with low residence times (15 seconds) and moderate UV irradiation (0.28 mW cm-2 at 365 nm), we demonstrated removal of up to 33% of model contaminant methylene blue (MB) and 13% of the antibiotic norfloxacin, both of which were introduced at a concentration of 3 mg L-1. The influence of molecular design parameters, such as hydrogel ionic strength, crosslinking density, and photocatalyst loading on transport and reactor performance were investigated and shown to have a strong influence on the transport properties of the hydrogels, providing options for optimizing the material to enhance treatment efficiency.

Systematic Review and Meta-Analysis of the Persistence and Disinfection of Human Coronaviruses and Their Viral Surrogates in Water and Wastewater

Comparison of biological weighting functions used to model endogenous sunlight inactivation rates of MS2 coliphage

Simplified process to determine rate constants for sunlight-mediated removal of trace organic and microbial contaminants in unit process open-water treatment wetlands

Systematic review and meta-analysis of decay rates of waterborne mammalian viruses and coliphages in surface waters

Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches

Nelson, K. L., Boehm, A. B., Davies-Colley, R. J., Dodd, M. C., Kohn, T., Linden, K. G., Liu, Y., Maraccini, P. A., McNeill, K., Mitch, W. A., Nguyen, T. H., Parker, K. M., Rodriguez, R. A., Sassoubre, L. M., Silverman, A. I., Wigginton, K. R., & Zepp, R. G. (n.d.).

Publication year

2018

Journal title

Environmental Science: Processes and Impacts

Volume

20

Issue

8

Page(s)

1089-1122

10.1039/c8em00047f

Abstract

Abstract

Health-relevant microorganisms present in natural surface waters and engineered treatment systems that are exposed to sunlight can be inactivated by a complex set of interacting mechanisms. The net impact of sunlight depends on the solar spectral irradiance, the susceptibility of the specific microorganism to each mechanism, and the water quality; inactivation rates can vary by orders of magnitude depending on the organism and environmental conditions. Natural organic matter (NOM) has a large influence, as it can attenuate radiation and thus decrease inactivation by endogenous mechanisms. Simultaneously NOM sensitizes the formation of reactive intermediates that can damage microorganisms via exogenous mechanisms. To accurately predict inactivation and design engineered systems that enhance solar inactivation, it is necessary to model these processes, although some details are not yet sufficiently well understood. In this critical review, we summarize the photo-physics, -chemistry, and -biology that underpin sunlight-mediated inactivation, as well as the targets of damage and cellular responses to sunlight exposure. Viruses that are not susceptible to exogenous inactivation are only inactivated if UVB wavelengths (280-320 nm) are present, such as in very clear, open waters or in containers that are transparent to UVB. Bacteria are susceptible to slightly longer wavelengths. Some viruses and bacteria (especially Gram-positive) are susceptible to exogenous inactivation, which can be initiated by visible as well as UV wavelengths. We review approaches to model sunlight-mediated inactivation and illustrate how the environmental conditions can dramatically shift the inactivation rate of organisms. The implications of this mechanistic understanding of solar inactivation are discussed for a range of applications, including recreational water quality, natural treatment systems, solar disinfection of drinking water (SODIS), and enhanced inactivation via the use of sensitizers and photocatalysts. Finally, priorities for future research are identified that will further our understanding of the key role that sunlight disinfection plays in natural systems and the potential to enhance this process in engineered systems.

Modeling the endogenous sunlight inactivation rates of laboratory strain and Wastewater E. coli and enterococci using biological weighting functions

Sunlight inactivation of viruses in open-water unit process treatment wetlands: Modeling endogenous and exogenous inactivation rates

On-farm treatment of wastewater used for vegetable irrigation: Bacteria and virus removal in small ponds in Accra, Ghana

Quality of irrigation water used for urban vegetable production

Sunlight inactivation of ms2 coliphage in the absence of photosensitizers: Modeling the endogenous inactivation rate using a photoaction spectrum

Quantification of human norovirus GII, human adenovirus, and fecal indicator organisms in wastewater used for irrigation in Accra, Ghana

Sunlight inactivation of human viruses and bacteriophages in coastal waters containing natural photosensitizers