168 research outputs found

    Characterization of Reverse Osmosis Membrane Foulants in Seawater Desalination

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    Integrating Algaculture into Small Wastewater Treatment Plants: Process Flow Options and Life Cycle Impacts

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    Algaculture has the potential to be a sustainable option for nutrient removal at wastewater treatment plants. The purpose of this study was to compare the environmental impacts of three likely algaculture integration strategies to a conventional nutrient removal strategy. Process modeling was used to determine life cycle inventory data and a comparative life cycle assessment was used to determine environmental impacts. Treatment scenarios included a base case treatment plant without nutrient removal, a plant with conventional nutrient removal, and three other cases with algal unit processes placed at the head of the plant, in a side stream, and at the end of the plant, respectively. Impact categories included eutrophication, global warming, ecotoxicity, and primary energy demand. Integrating algaculture prior to activated sludge proved to be most beneficial of the scenarios considered for all impact categories; however, this scenario would also require primary sedimentation and impacts of that unit process should be considered for implementation of such a system

    Navigating the Academic Job Search for Environmental Engineers: Guidance for Job Seekers and Mentors

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    Students and postdoctoral associates interested in tenure-track environmental engineering positions have limited resources to aid them. The Student Services Committee (SSC) of the Association of Environmental Engineering and Science Professors (AEESP) organized a workshop to fill some of the need. Newly hired faculty and experienced search committee and department chairs shared information on how to create competitive applications. Students and postdoctoral associates were also provided with individualized feedback on their faculty application packages. Survey data were collected for all participants, and these data are presented in this paper along with tips shared during the workshop and information collected from the literature. The objective of this paper is to share that information (1) to inform applicants (students and postdoctoral associates) about the academic job search process, and (2) to inform mentors about how to mentor applicants. Survey responses revealed that participants felt they learned valuable information about the job search process. They found the personalized feedback on application packages to be the most helpful activity; other mentors are encouraged to provide similar personalized feedback. A wiki website component included in the workshop was effective at engaging the participants and helped broaden the impact beyond the workshop attendees. Key lessons learned by comparing workshop results with literature were the importance of fit, the unique diversity of environmental engineering, mentoring and networking, Ph.D. planning sessions, being informed, and becoming a more skilled candidate. The recommendations presented in this paper can be used by students, postdoctoral associates, and their mentors to facilitate the candidate’s path toward academia

    The Structure-Function Relationship of PAMAM Dendrimers as Robust Oil Dispersants

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    PAMAM dendrimers have recently been investigated as efficient and biocompatible oil dispersants utilizing their encapsulation capacity; however, their high cationic charge density has been shown to be cytotoxic. It is therefore imperative to mitigate cationic charge-induced toxicity and understand the effects of such changes. Presented here is a synergistic experimental and computational approach to examine the effects of varying terminal surface charge on the capacity of dendrimers to disperse model liner, polycyclic aromatic, and hybrid hydrocarbons. Uncharged dendrimers collapse by forming intramolecular hydrogen bonds, which reduce the hosting capability. On the other hand, changing the surface charges from positive to negative greatly shifts the pKa of tertiary amines of the PAMAM dendrimer interior. As a result, the negatively charged dendrimers have a significant percentage of tertiary amines protonated, ∼30%. This unexpected change in the interior protonation state causes electrostatic interactions with the anionic terminal groups, leading to contraction and a marked decrease in hydrocarbon hosting capacity. The present work highlights the robust nature of dendrimer oil dispersion and also illuminates potentially unintended or unanticipated effects of varying dendrimer surface chemistry on their encapsulation or hosting efficacy, which is important for their environmental, industrial, and biomedical applications
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