31 research outputs found

    Quantifying Spatiotemporal Impacts of the Interaction of Water Scarcity and Water Use by the Global Semiconductor Manufacturing Industry

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    The high-tech semiconductor manufacturing sector is integral to the international electronics industry and was valued at over $400 billion USD in 2017. Intensive water use by this industry is well-documented and this work provides a spatially explicitly assessment of water use impacts by nearly 100% of global semiconductor manufacturing capacity. Both direct manufacturing water use and water use from electricity were considered as part of a facility’s total withdrawal. Manufacturing water withdrawals were estimated by using technology-specific water and electricity use data, reported at the semiconductor chip or wafer level from the life cycle literature and industry estimates. Electricity water use intensity (WUI) factors were gleaned from the literature and regional electricity WUI factors were derived for China and the U.S. Geolocation of semiconductor manufacturing facilities allowed for summation of water withdrawals at various spatial extents (i.e. watershed, country, and globally). This data was combined with calculated regional or country-level electricity water use factors to estimate total water withdrawals by a facility. Geolocation of data also allowed for calculation of watershed specific scarcity-weighted withdrawals. Scarcity-weighted withdrawals were ascertained by multiplying facility water withdrawal data by the AWaRE water scarcity characterization factor available for each of 202 watersheds associated with semiconductor manufacturing facilities. These data were used to identify and map hotspots of industry water use, which is especially important for areas of industry growth such as China. This analysis is useful as a benchmark for global semiconductor industry water withdrawals and may assist OEMs in decisions about supply chain sourcing. This could also guide semiconductor manufacturers in prioritizing locations and time periods to implement water-saving technologies or employ less water intensive electricity sources. Additionally, the spatially explicit water use data for the semiconductor sector can be used to improve existing databases of national and regional sector-specific water use coefficients that are often applied in LCA input-output studies

    Lead in Residential Water Heaters: An Analysis of Lead Dissolution Kinetics in Non-Ideal Aquatic Environments

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    Lead dioxide, a lead corrosion product, is an important contributor to residential drinking water contamination. A neurotoxin and endocrine disruptor, lead poses serious human health concerns. Despite previous research on water distribution pipes, lead in water heating and softening systems is unexplored. Standard tank water heaters and water softeners have significantly different aquatic environments compared to distribution pipes, due to increased temperature and ion concentration levels. This research verifies the iodometric method for lead dioxide detection and quantifies total lead and dissolved lead(IV) ions over time in simulated water heater and softener environments. Initial experiments confirmed the iodometric method for lead(IV) and measured absorbance with UV-spectrometry. Another set of experiments quantified the dissolved lead(IV) cation in a filtered lead-water mixture by applying the iodometric method to batch reactors, and varying water source (DI, synthetic tap water), temperature (25, 55°C), and NaCl concentration (0.175, 0.584 g/L). Furthermore, each sample was analyzed by ICP-OES to determine the concentration of elemental lead present. The iodometric method resulted in an 80% recovery of dosed lead over one hour. Dissolved lead(IV) ion, conversely, had very little recovery after a week in each batch reactor. Overall, the iodometric method is an accurate and rapid tool for quantifying and comparing dissolution kinetics of total lead dioxide. In contrast, at the temperatures and ionic strength levels investigated, lead(IV) cations may exist in such low concentrations that iodometry may not be an accurate detection method. Future research should consider additional lead species for complete lead dissolution models of water heating and softening systems

    Characterization of Landfill Leachate for Enhanced Metal Recovery

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    Landfills contain a trove of valuable materials, such as critical, precious, and rare earth metals, that are integral to the United State’s economy and national security. The leachate that filters through landfills picks up these materials, which allows for the possibility of recovery. For this research, samples will be analyzed from landfills throughout the Midwestern United States to provide a baseline on water quality constituents, elements present, and microbial activity. Preliminary data for this study was acquired by analyzing samples of landfill leachate from a landfill in northern Indiana. pH readings indicate that the leachate is slightly basic. It also contains around 1-2% total solids. Inductively coupled plasma optical emission spectrometry (ICP-OES) was also used to identify elements present in the samples. Of the 66 elements considered in the analysis, 35 were detectable in quantifiable amounts. The most common elements present were sodium, potassium, magnesium, calcium, boron, and sulfur. Critical elements such as lithium and chromium were also found in the leachate. Future research will develop an integrated method applying microbial bioleaching, physico-chemical processes, and membrane filtration to recover critical elements from landfill leachate

    Characterization of Microbial Populations in Landfill Leachate

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    In the United States, municipal solid waste (MSW) landfills remain a potential mining source of recoverable materials, including but not limited to critical, precious, and rare earth metals found in electronic waste. This is possible due to collectible leachate that filters through MSW landfills, carrying metals, nutrients of value, and microbes—some of which may hold key metal bioleaching properties—within. The purpose of this study is to begin analyzing leachate from MSW landfills in the American Midwest to understand the composition of microbial communities within these landfills. Landfill leachate samples sourced in northern Indiana, representing the landfill process during unique times of operation, were used in this study. Culture-independent studies, utilizing both DNA extraction and PCR for communities of archaea, bacteria, and fungi, were performed on leachate samples. Current results indicate that in 6 of 11 samples, both bacterial and archaeal DNA were likely present, while 1 additional sample yielded only amplified archaeal DNA, and 1 more yielded only amplified bacterial DNA. This implies the presence of both archaea and bacteria which may hold metal bioleaching capabilities. Follow-up research will involve analyzing other Midwestern leachate samples, identifying landfill microbes with metal bioleaching properties, and developing a way to integrate these microbes with membrane filtration and other physico-chemical processes to improve recovery of important metals from leachate

    Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

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    https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd

    Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes

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    publisher: Elsevier articletitle: Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes journaltitle: Cell articlelink: https://doi.org/10.1016/j.cell.2018.05.046 content_type: article copyright: © 2018 Elsevier Inc

    Remediation of Aromatic Hydrocarbons in Low Permeability Soils: Updating the Remediation Decision Tree (Synthesis Study)

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    Because of the large number of technologies for in situ remediation, the very different types of contaminants to which these technologies are applicable, and the wide range of field conditions, it can be difficult to choose an optimal technology for a specific site. Sorting and prioritizing the various factors which contribute to the success of a particular clean-up can be daunting. Furthermore, non-technical factors, such as those in the legal, political, or financial realm, may also influence which technology is ultimately chosen. Most in situ treatment methods are effective in permeable soil. However, much of Indiana soil is low-permeability, so applicability of these methods is limited. One of the few currently viable options is massive (and expensive) excavation and disposal. The purpose of the study is to develop decision-support tools for use by INDOT staff involved with site remediation. The decision-support tools include remediation decision-trees for choosing technologies or combinations of technologies appropriate for specific types of sites, including sites with low-permeability soil. In order to develop decisiontrees, it is necessary to conduct a comprehensive analysis of remediation technologies, with a focus on investigations of aromatic hydrocarbons and low-permeability soils. An additional objective is to construct a database of remediated sites in the region. The types of sites will be screened so that they are as similar as possible to sites of interest to INDOT. In particular, information from sites that have been successfully remediated will be chosen. This project will expand the scientific basis for the development and application of innovative treatment for contaminated sites owned and operated by INDOT. Potential benefits include a more effective means of remediating benzene and other fuel hydrocarbons without having to excavate and dispose of contaminated soil. The use of a remediation decision tree may decrease the time needed to choose an effective technology
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