 |
Derick G. Brown Associate Professor Department of Civil & Environmental Engineering Fritz Engineering Laboratory Office Hours |
|
Information for Graduate Students & Research Group Members |
Graduate Student Expectations (Updated 15 July 2008)
Laboratory Protocol and Etiquette (Updated 15 July 2008)
Open Research Assistant Position in Environmental Biotechnology (Updated 16 July 2008)
|
Education and Professional Background |
Education:
Research and Work Experience:
Affiliated Programs at Lehigh:
Professional Society Memberships:
Patents:
|
Teaching |
Undergraduate Courses:
Graduate Courses:
Independent Special Topics/Research Courses:
Students can take special topics or research-based courses as technical electives. Special topics are developed based on interests and initiative by the students. These courses include CEE 281 and CEE 104 (undergraduate) and CEE 475 (graduate). For research courses, students either become involved in on-going research in my laboratory or the student and I develop a research project of mutual interest. The research courses include CEE 211 (undergraduate) and CEE 479 (graduate). I have also mentored students in bioengineering research courses (BioE 132/142/242).
|
Research |
Links of Interest on my research program:
Research Areas:
My main research interests are in the area of environmental biotechnology, especially on the interactions between microorganisms and surfaces. One component of my research in this area focuses on how surfaces can affect the metabolic activity and survival of microorganisms. My current research in this area is focusing on the mechanisms by which surfaces impact metabolic activity. To date, we have demonstrated that adhered bacteria have higher levels of adenosine triphosphate (ATP), the key energy carrier in cells, and we are linking this ATP increase to physiochemical interactions between the cell surface and the solid substrate. Goals with this work include (a) understanding the relationships between biological and physio-chemical processes in the formation of cellular energy, and (b) determining how we, as engineers, can utilize these interactions for purposes such as designing materials to enhance biological wastewater treatment, minimize pathogenic organism survival on man-made surfaces, and minimize biofouling of immersed surfaces. Understanding the effects of surfaces on metabolic activity and survival will also provide insight into natural environmental processes, including microbial interactions with mineral surfaces and long-term survival of microorganisms in oligotrophic environments, such as the deep subsurface. Click here for more information.
A second component of my research in the interactions of microorganisms and surfaces is the attachment and transport of microorganisms through porous media. Most disease outbreaks occur due to drinking of untreated groundwater, and my research in this area is to determine how long-distance travel of microorganisms occurs in the subsurface. One aspect of this research is on how surfactants found in common detergents can enhance microbial transport. We have recently shown that surfactants can significantly enhance the transport of bacteria through both saturated and unsaturated porous media, and this enhanced transport is a function of surfactant structure and concentration, and solution ionic strength. As surfactants are the largest man-made component of domestic wastewater, surfactant-enhanced transport can be a very important process for the transport of pathogenic organisms from on-site wastewater treatment systems, such as septic systems, to drinking water wells. We have also recently shown that a key parameter describing microbial transport through saturated porous media is a distributed parameter, and because of this, much longer transport distances are predicted than when considering this parameter to be a single value. My current research is focusing on these aspects of microbial transport, with on-going and planned experimental work focusing on the effect of length scale, ranging from centimeters up to ten meters. Click here for more information.
Another research area of mine is in biodegradation kinetics. My interests relate to biodegradation of hydrophobic organic compounds (HOC), such as polycyclic aromatic hydrocarbons, and multisubstrate biodegradation. In one recent study we developed a theory on how surfactant sorption on the bacterial cell surface affects the bioavailability of surfactant-solubilized HOCs, and we demonstrated how sorbed surfactant enhances the concentration of phenanthrene (a model HOC) on the bacterial cell surface. We are also examining how bacteriophage (viruses that infect bacteria) impact biodegradation kinetics, with the ultimate goal of providing a more realistic model of environmental and engineered systems. Click here for more information.
Finally, one other research area of mine is in multicomponent non-aqueous phase liquids, with a focus on coal tars. My interests are on (a) how we can model and perform risk assessments on these complex mixtures; (b) dissolution, mass transfer and sorption of the individual components in the subsurface; and (c) specific interfacial processes of these complex mixtures, such as the interfacial film that forms on coal tars. Click here for more information.
Recent Publications: (Complete List of Publications and Presentations)
Abramson, A. and Brown, D.G. 2007. "Influence of solution ionic strength on the collision efficiency distribution and predicted transport distance of a Sphingomonas sp. flowing through porous media." Water Research, 41(19):4435-4445.
Brown, D.G. 2007. "Relationship between micellar and hemi-micellar processes and the bioavailability of surfactant-solubilized hydrophobic organic compounds." Environ. Sci. Technol., 41(4):1194-1199.
X. Li, Brown, D.G., Zhang, W. 2007. "Zero-valent iron nanoparticles for stabilization of biosolids." Journal of Nanoparticle Research, 9(2):233-243.
Brown, D.G. 2007. "Adaptable method for estimation of parameters describing bacterial transport through porous media from column effluent data: Optimization based on data quality and quantity." Colloids and Surfaces A: Physiochemical and Engineering Aspects, 296(1-3):19-28.